boringssl/include/openssl/x509.h

// Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
// Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef OPENSSL_HEADER_X509_H
#define OPENSSL_HEADER_X509_H

#include <openssl/base.h>  // IWYU pragma: export

#include <time.h>

#include <openssl/asn1.h>
#include <openssl/bio.h>
#include <openssl/cipher.h>
#include <openssl/conf.h>
#include <openssl/dh.h>
#include <openssl/dsa.h>
#include <openssl/ec.h>
#include <openssl/ecdh.h>
#include <openssl/ecdsa.h>
#include <openssl/evp.h>
#include <openssl/obj.h>
#include <openssl/pkcs7.h>
#include <openssl/pool.h>
#include <openssl/rsa.h>
#include <openssl/sha2.h>
#include <openssl/stack.h>
#include <openssl/x509v3_errors.h>  // IWYU pragma: export

#if defined(__cplusplus)
extern "C" {
#endif


// Legacy X.509 library.
//
// This header is part of OpenSSL's X.509 implementation. It is retained for
// compatibility but should not be used by new code. The functions are difficult
// to use correctly, and have buggy or non-standard behaviors. They are thus
// particularly prone to behavior changes and API removals, as BoringSSL
// iterates on these issues.
//
// In the future, a replacement library will be available. Meanwhile, minimize
// dependencies on this header where possible.


// Certificates.
//
// An `X509` object represents an X.509 certificate, defined in RFC 5280.
//
// Although an `X509` is a mutable object, mutating an `X509` can give incorrect
// results. Callers typically obtain `X509`s by parsing some input with
// `d2i_X509`, etc. Such objects carry information such as the serialized
// TBSCertificate and decoded extensions, which will become inconsistent when
// mutated.
//
// Instead, mutation functions should only be used when issuing new
// certificates, as described in a later section.

DEFINE_STACK_OF(X509)

// X509 is an `ASN1_ITEM` whose ASN.1 type is X.509 Certificate (RFC 5280) and C
// type is `X509*`.
DECLARE_ASN1_ITEM(X509)

// X509_up_ref adds one to the reference count of `x509` and returns one.
OPENSSL_EXPORT int X509_up_ref(X509 *x509);

// X509_dup_ref increments the reference count of `x509` and returns `x509`.
// The caller must call `X509_free` on the result to release the reference.
//
// WARNING: Although the result is non-const for use with `X509_free`, it is
// still shared with other parts of the application for the same object. Avoid
// mutating shared `X509`s.
OPENSSL_EXPORT X509 *X509_dup_ref(const X509 *x509);

// X509_chain_up_ref returns a newly-allocated `STACK_OF(X509)` containing a
// shallow copy of `chain`, or NULL on error. That is, the return value has the
// same contents as `chain`, and each `X509`'s reference count is incremented by
// one.
OPENSSL_EXPORT STACK_OF(X509) *X509_chain_up_ref(STACK_OF(X509) *chain);

// X509_dup returns a newly-allocated copy of `x509`, or NULL on error. This
// function works by serializing the structure, so auxiliary properties (see
// `i2d_X509_AUX`) are not preserved. Additionally, if `x509` is incomplete,
// this function may fail.
OPENSSL_EXPORT X509 *X509_dup(const X509 *x509);

// X509_free decrements `x509`'s reference count and, if zero, releases memory
// associated with `x509`.
OPENSSL_EXPORT void X509_free(X509 *x509);

// d2i_X509 parses up to `len` bytes from `*inp` as a DER-encoded X.509
// Certificate (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509 *d2i_X509(X509 **out, const uint8_t **inp, long len);

// X509_parse_with_algorithms parses an X.509 structure from `buf` and returns a
// fresh X509 or NULL on error. There must not be any trailing data in `buf`.
// The returned structure (if any) increments `buf`'s reference count and
// retains a reference to it.
//
// Only the `num_algs` algorithms from `algs` will be considered when parsing
// the certificate's public key. If the certificate uses a different algorithm,
// it will still be parsed, but `X509_get0_pubkey` will return NULL.
OPENSSL_EXPORT X509 *X509_parse_with_algorithms(CRYPTO_BUFFER *buf,
                                                const EVP_PKEY_ALG *const *algs,
                                                size_t num_algs);

// X509_parse_from_buffer behaves like `X509_parse_with_algorithms` but uses a
// default algorithm list.
OPENSSL_EXPORT X509 *X509_parse_from_buffer(CRYPTO_BUFFER *buf);

// i2d_X509 marshals `x509` as a DER-encoded X.509 Certificate (RFC 5280), as
// described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509(const X509 *x509, uint8_t **outp);

// X509_VERSION_* are X.509 version numbers. Note the numerical values of all
// defined X.509 versions are one less than the named version.
#define X509_VERSION_1 0
#define X509_VERSION_2 1
#define X509_VERSION_3 2

// X509_get_version returns the numerical value of `x509`'s version, which will
// be one of the `X509_VERSION_*` constants.
OPENSSL_EXPORT long X509_get_version(const X509 *x509);

// X509_get0_serialNumber returns `x509`'s serial number.
OPENSSL_EXPORT const ASN1_INTEGER *X509_get0_serialNumber(const X509 *x509);

// X509_get0_notBefore returns `x509`'s notBefore time.
OPENSSL_EXPORT const ASN1_TIME *X509_get0_notBefore(const X509 *x509);

// X509_get0_notAfter returns `x509`'s notAfter time.
OPENSSL_EXPORT const ASN1_TIME *X509_get0_notAfter(const X509 *x509);

// X509_get_issuer_name returns `x509`'s issuer.
OPENSSL_EXPORT X509_NAME *X509_get_issuer_name(const X509 *x509);

// X509_get_subject_name returns `x509`'s subject.
OPENSSL_EXPORT X509_NAME *X509_get_subject_name(const X509 *x509);

// X509_get_X509_PUBKEY returns the public key of `x509`. Note this function is
// not const-correct for legacy reasons. Callers should not modify the returned
// object.
OPENSSL_EXPORT X509_PUBKEY *X509_get_X509_PUBKEY(const X509 *x509);

// X509_get0_pubkey returns `x509`'s public key as an `EVP_PKEY`, or NULL if the
// public key was unsupported or could not be decoded. The `EVP_PKEY` is cached
// in `x509`, so callers must not mutate the result.
OPENSSL_EXPORT EVP_PKEY *X509_get0_pubkey(const X509 *x509);

// X509_get_pubkey behaves like `X509_get0_pubkey` but increments the reference
// count on the `EVP_PKEY`. The caller must release the result with
// `EVP_PKEY_free` when done. The `EVP_PKEY` is cached in `x509`, so callers
// must not mutate the result.
OPENSSL_EXPORT EVP_PKEY *X509_get_pubkey(const X509 *x509);

// X509_get0_pubkey_bitstr returns the BIT STRING portion of `x509`'s public
// key. Note this does not contain the AlgorithmIdentifier portion.
//
// WARNING: This function returns a non-const pointer for OpenSSL compatibility,
// but the caller must not modify the resulting object. Doing so will break
// internal invariants in `x509`.
OPENSSL_EXPORT ASN1_BIT_STRING *X509_get0_pubkey_bitstr(const X509 *x509);

// X509_check_private_key returns one if `x509`'s public key matches `pkey` and
// zero otherwise.
OPENSSL_EXPORT int X509_check_private_key(const X509 *x509,
                                          const EVP_PKEY *pkey);

// X509_get0_uids sets `*out_issuer_uid` to a non-owning pointer to the
// issuerUID field of `x509`, or NULL if `x509` has no issuerUID. It similarly
// outputs `x509`'s subjectUID field to `*out_subject_uid`.
//
// Callers may pass NULL to either `out_issuer_uid` or `out_subject_uid` to
// ignore the corresponding field.
OPENSSL_EXPORT void X509_get0_uids(const X509 *x509,
                                   const ASN1_BIT_STRING **out_issuer_uid,
                                   const ASN1_BIT_STRING **out_subject_uid);

// The following bits are returned from `X509_get_extension_flags`.

// EXFLAG_BCONS indicates the certificate has a basic constraints extension.
#define EXFLAG_BCONS 0x1
// EXFLAG_KUSAGE indicates the certificate has a key usage extension.
#define EXFLAG_KUSAGE 0x2
// EXFLAG_XKUSAGE indicates the certificate has an extended key usage extension.
#define EXFLAG_XKUSAGE 0x4
// EXFLAG_CA indicates the certificate has a basic constraints extension with
// the CA bit set.
#define EXFLAG_CA 0x10
// EXFLAG_SI indicates the certificate is self-issued, i.e. its subject and
// issuer names match.
#define EXFLAG_SI 0x20
// EXFLAG_V1 indicates an X.509v1 certificate.
#define EXFLAG_V1 0x40
// EXFLAG_INVALID indicates an error processing some extension. The certificate
// should not be accepted. Note the lack of this bit does not imply all
// extensions are valid, only those used to compute extension flags.
#define EXFLAG_INVALID 0x80
// EXFLAG_SET is an internal bit that indicates extension flags were computed.
#define EXFLAG_SET 0x100
// EXFLAG_CRITICAL indicates an unsupported critical extension. The certificate
// should not be accepted.
#define EXFLAG_CRITICAL 0x200
// EXFLAG_SS indicates the certificate is likely self-signed. That is, if it is
// self-issued, its authority key identifier (if any) matches itself, and its
// key usage extension (if any) allows certificate signatures. The signature
// itself is not checked in computing this bit.
#define EXFLAG_SS 0x2000

// X509_get_extension_flags decodes a set of extensions from `x509` and returns
// a collection of `EXFLAG_*` bits which reflect `x509`. If there was an error
// in computing this bitmask, the result will include the `EXFLAG_INVALID` bit.
OPENSSL_EXPORT uint32_t X509_get_extension_flags(X509 *x509);

// X509_get_pathlen returns path length constraint from the basic constraints
// extension in `x509`. (See RFC 5280, section 4.2.1.9.) It returns -1 if the
// constraint is not present, or if some extension in `x509` was invalid.
//
// TODO(crbug.com/boringssl/381): Decoding an `X509` object will not check for
// invalid extensions. To detect the error case, call
// `X509_get_extension_flags` and check the `EXFLAG_INVALID` bit.
OPENSSL_EXPORT long X509_get_pathlen(X509 *x509);

// X509v3_KU_* are key usage bits returned from `X509_get_key_usage`.
#define X509v3_KU_DIGITAL_SIGNATURE 0x0080
#define X509v3_KU_NON_REPUDIATION 0x0040
#define X509v3_KU_KEY_ENCIPHERMENT 0x0020
#define X509v3_KU_DATA_ENCIPHERMENT 0x0010
#define X509v3_KU_KEY_AGREEMENT 0x0008
#define X509v3_KU_KEY_CERT_SIGN 0x0004
#define X509v3_KU_CRL_SIGN 0x0002
#define X509v3_KU_ENCIPHER_ONLY 0x0001
#define X509v3_KU_DECIPHER_ONLY 0x8000

// X509_get_key_usage returns a bitmask of key usages (see Section 4.2.1.3 of
// RFC 5280) which `x509` is valid for. This function only reports the first 16
// bits, in a little-endian byte order, but big-endian bit order. That is, bits
// 0 though 7 are reported at 1<<7 through 1<<0, and bits 8 through 15 are
// reported at 1<<15 through 1<<8.
//
// Instead of depending on this bit order, callers should compare against the
// `X509v3_KU_*` constants.
//
// If `x509` has no key usage extension, all key usages are valid and this
// function returns `UINT32_MAX`. If there was an error processing `x509`'s
// extensions, or if the first 16 bits in the key usage extension were all zero,
// this function returns zero.
OPENSSL_EXPORT uint32_t X509_get_key_usage(X509 *x509);

// XKU_* are extended key usage bits returned from
// `X509_get_extended_key_usage`.
#define XKU_SSL_SERVER 0x1
#define XKU_SSL_CLIENT 0x2
#define XKU_SMIME 0x4
#define XKU_CODE_SIGN 0x8
#define XKU_SGC 0x10
#define XKU_OCSP_SIGN 0x20
#define XKU_TIMESTAMP 0x40
#define XKU_DVCS 0x80
#define XKU_ANYEKU 0x100

// X509_get_extended_key_usage returns a bitmask of extended key usages (see
// Section 4.2.1.12 of RFC 5280) which `x509` is valid for. The result will be
// a combination of `XKU_*` constants. If checking an extended key usage not
// defined above, callers should extract the extended key usage extension
// separately, e.g. via `X509_get_ext_d2i`.
//
// If `x509` has no extended key usage extension, all extended key usages are
// valid and this function returns `UINT32_MAX`. If there was an error
// processing `x509`'s extensions, or if `x509`'s extended key usage extension
// contained no recognized usages, this function returns zero.
OPENSSL_EXPORT uint32_t X509_get_extended_key_usage(X509 *x509);

// X509_get0_subject_key_id returns `x509`'s subject key identifier, if present.
// (See RFC 5280, section 4.2.1.2.) It returns NULL if the extension is not
// present or if some extension in `x509` was invalid.
//
// TODO(crbug.com/boringssl/381): Decoding an `X509` object will not check for
// invalid extensions. To detect the error case, call
// `X509_get_extension_flags` and check the `EXFLAG_INVALID` bit.
OPENSSL_EXPORT const ASN1_OCTET_STRING *X509_get0_subject_key_id(X509 *x509);

// X509_get0_authority_key_id returns keyIdentifier of `x509`'s authority key
// identifier, if the extension and field are present. (See RFC 5280,
// section 4.2.1.1.) It returns NULL if the extension is not present, if it is
// present but lacks a keyIdentifier field, or if some extension in `x509` was
// invalid.
//
// TODO(crbug.com/boringssl/381): Decoding an `X509` object will not check for
// invalid extensions. To detect the error case, call
// `X509_get_extension_flags` and check the `EXFLAG_INVALID` bit.
OPENSSL_EXPORT const ASN1_OCTET_STRING *X509_get0_authority_key_id(X509 *x509);

DEFINE_STACK_OF(GENERAL_NAME)
typedef STACK_OF(GENERAL_NAME) GENERAL_NAMES;

// X509_get0_authority_issuer returns the authorityCertIssuer of `x509`'s
// authority key identifier, if the extension and field are present. (See
// RFC 5280, section 4.2.1.1.) It returns NULL if the extension is not present,
// if it is present but lacks an authorityCertIssuer field, or if some extension
// in `x509` was invalid.
//
// TODO(crbug.com/boringssl/381): Decoding an `X509` object will not check for
// invalid extensions. To detect the error case, call
// `X509_get_extension_flags` and check the `EXFLAG_INVALID` bit.
OPENSSL_EXPORT const GENERAL_NAMES *X509_get0_authority_issuer(X509 *x509);

// X509_get0_authority_serial returns the authorityCertSerialNumber of `x509`'s
// authority key identifier, if the extension and field are present. (See
// RFC 5280, section 4.2.1.1.) It returns NULL if the extension is not present,
// if it is present but lacks an authorityCertSerialNumber field, or if some
// extension in `x509` was invalid.
//
// TODO(crbug.com/boringssl/381): Decoding an `X509` object will not check for
// invalid extensions. To detect the error case, call
// `X509_get_extension_flags` and check the `EXFLAG_INVALID` bit.
OPENSSL_EXPORT const ASN1_INTEGER *X509_get0_authority_serial(X509 *x509);

// X509_get0_extensions returns `x509`'s extension list, or NULL if `x509` omits
// it.
OPENSSL_EXPORT const STACK_OF(X509_EXTENSION) *X509_get0_extensions(
    const X509 *x509);

// X509_get_ext_count returns the number of extensions in `x`.
OPENSSL_EXPORT int X509_get_ext_count(const X509 *x);

// X509_get_ext_by_NID behaves like `X509v3_get_ext_by_NID` but searches for
// extensions in `x`.
OPENSSL_EXPORT int X509_get_ext_by_NID(const X509 *x, int nid, int lastpos);

// X509_get_ext_by_OBJ behaves like `X509v3_get_ext_by_OBJ` but searches for
// extensions in `x`.
OPENSSL_EXPORT int X509_get_ext_by_OBJ(const X509 *x, const ASN1_OBJECT *obj,
                                       int lastpos);

// X509_get_ext_by_critical behaves like `X509v3_get_ext_by_critical` but
// searches for extensions in `x`.
OPENSSL_EXPORT int X509_get_ext_by_critical(const X509 *x, int crit,
                                            int lastpos);

// X509_get_ext returns the extension in `x` at index `loc`, or NULL if `loc` is
// out of bounds. This function returns a non-const pointer for OpenSSL
// compatibility, but callers should not mutate the result.
OPENSSL_EXPORT X509_EXTENSION *X509_get_ext(const X509 *x, int loc);

// X509_get_ext_d2i behaves like `X509V3_get_d2i` but looks for the extension in
// `x509`'s extension list.
//
// WARNING: This function is difficult to use correctly. See the documentation
// for `X509V3_get_d2i` for details.
OPENSSL_EXPORT void *X509_get_ext_d2i(const X509 *x509, int nid,
                                      int *out_critical, int *out_idx);

// X509_get0_tbs_sigalg returns the signature algorithm in `x509`'s
// TBSCertificate. For the outer signature algorithm, see `X509_get0_signature`.
//
// Certificates with mismatched signature algorithms will successfully parse,
// but they will be rejected when verifying.
OPENSSL_EXPORT const X509_ALGOR *X509_get0_tbs_sigalg(const X509 *x509);

// X509_get0_signature sets `*out_sig` and `*out_alg` to the signature and
// signature algorithm of `x509`, respectively. Either output pointer may be
// NULL to ignore the value.
//
// This function outputs the outer signature algorithm. For the one in the
// TBSCertificate, see `X509_get0_tbs_sigalg`. Certificates with mismatched
// signature algorithms will successfully parse, but they will be rejected when
// verifying.
OPENSSL_EXPORT void X509_get0_signature(const ASN1_BIT_STRING **out_sig,
                                        const X509_ALGOR **out_alg,
                                        const X509 *x509);

// X509_get_signature_nid returns the NID corresponding to `x509`'s signature
// algorithm, or `NID_undef` if the signature algorithm does not correspond to
// a known NID.
OPENSSL_EXPORT int X509_get_signature_nid(const X509 *x509);

// i2d_X509_tbs serializes the TBSCertificate portion of `x509`, as described in
// `i2d_SAMPLE`.
//
// This function preserves the original encoding of the TBSCertificate and may
// not reflect modifications made to `x509`. It may be used to manually verify
// the signature of an existing certificate. To generate certificates, use
// `i2d_re_X509_tbs` instead.
OPENSSL_EXPORT int i2d_X509_tbs(const X509 *x509, uint8_t **outp);

// X509_verify checks that `x509` has a valid signature by `pkey`. It returns
// one if the signature is valid and zero otherwise. Note this function only
// checks the signature itself and does not perform a full certificate
// validation.
OPENSSL_EXPORT int X509_verify(const X509 *x509, EVP_PKEY *pkey);

// X509_get1_email returns a newly-allocated list of NUL-terminated strings
// containing all email addresses in `x509`'s subject and all rfc822name names
// in `x509`'s subject alternative names. Email addresses which contain embedded
// NUL bytes are skipped. The results are returned in an arbitrary order.
//
// On error, or if there are no such email addresses, it returns NULL. When
// done, the caller must release the result with `X509_email_free`.
OPENSSL_EXPORT STACK_OF(OPENSSL_STRING) *X509_get1_email(const X509 *x509);

// X509_get1_ocsp returns a newly-allocated list of NUL-terminated strings
// containing all OCSP URIs in `x509`. That is, it collects all URI
// AccessDescriptions with an accessMethod of id-ad-ocsp in `x509`'s authority
// information access extension. URIs which contain embedded NUL bytes are
// skipped. The results are returned in an arbitrary order.
//
// On error, or if there are no such URIs, it returns NULL. When done, the
// caller must release the result with `X509_email_free`.
OPENSSL_EXPORT STACK_OF(OPENSSL_STRING) *X509_get1_ocsp(const X509 *x509);

// X509_email_free releases memory associated with `sk`, including `sk` itself.
// Each `OPENSSL_STRING` in `sk` must be a NUL-terminated string allocated with
// `OPENSSL_malloc`. If `sk` is NULL, no action is taken.
OPENSSL_EXPORT void X509_email_free(STACK_OF(OPENSSL_STRING) *sk);

// X509_cmp compares `a` and `b` and returns zero if they are equal, a negative
// number if `b` sorts after `a` and a negative number if `a` sorts after `b`.
// The sort order implemented by this function is arbitrary and does not
// reflect properties of the certificate such as expiry. Applications should not
// rely on the order itself.
//
// TODO(https://crbug.com/boringssl/355): This function works by comparing a
// cached hash of the encoded certificate. If `a` or `b` could not be
// serialized, the current behavior is to compare all unencodable certificates
// as equal. This function should only be used with `X509` objects that were
// parsed from bytes and never mutated.
OPENSSL_EXPORT int X509_cmp(const X509 *a, const X509 *b);


// Issuing certificates.
//
// An `X509` object may also represent an incomplete certificate. Callers may
// construct empty `X509` objects, fill in fields individually, and finally sign
// the result. The following functions may be used for this purpose.

// X509_new returns a newly-allocated, empty `X509` object, or NULL on error.
// This produces an incomplete certificate which may be filled in to issue a new
// certificate.
OPENSSL_EXPORT X509 *X509_new(void);

// X509_set_version sets `x509`'s version to `version`, which should be one of
// the `X509V_VERSION_*` constants. It returns one on success and zero on error.
//
// If unsure, use `X509_VERSION_3`.
OPENSSL_EXPORT int X509_set_version(X509 *x509, long version);

// X509_set_serialNumber sets `x509`'s serial number to `serial`. It returns one
// on success and zero on error.
OPENSSL_EXPORT int X509_set_serialNumber(X509 *x509,
                                         const ASN1_INTEGER *serial);

// X509_set1_notBefore sets `x509`'s notBefore time to `tm`. It returns one on
// success and zero on error.
OPENSSL_EXPORT int X509_set1_notBefore(X509 *x509, const ASN1_TIME *tm);

// X509_set1_notAfter sets `x509`'s notAfter time to `tm`. it returns one on
// success and zero on error.
OPENSSL_EXPORT int X509_set1_notAfter(X509 *x509, const ASN1_TIME *tm);

// X509_getm_notBefore returns a mutable pointer to `x509`'s notBefore time.
OPENSSL_EXPORT ASN1_TIME *X509_getm_notBefore(X509 *x509);

// X509_getm_notAfter returns a mutable pointer to `x509`'s notAfter time.
OPENSSL_EXPORT ASN1_TIME *X509_getm_notAfter(X509 *x);

// X509_set_issuer_name sets `x509`'s issuer to a copy of `name`. It returns one
// on success and zero on error.
OPENSSL_EXPORT int X509_set_issuer_name(X509 *x509, const X509_NAME *name);

// X509_set_subject_name sets `x509`'s subject to a copy of `name`. It returns
// one on success and zero on error.
OPENSSL_EXPORT int X509_set_subject_name(X509 *x509, const X509_NAME *name);

// X509_set_pubkey sets `x509`'s public key to `pkey`. It returns one on success
// and zero on error. This function does not take ownership of `pkey` and
// internally copies and updates reference counts as needed.
OPENSSL_EXPORT int X509_set_pubkey(X509 *x509, EVP_PKEY *pkey);

// X509_delete_ext removes the extension in `x` at index `loc` and returns the
// removed extension, or NULL if `loc` was out of bounds. If non-NULL, the
// caller must release the result with `X509_EXTENSION_free`.
OPENSSL_EXPORT X509_EXTENSION *X509_delete_ext(X509 *x, int loc);

// X509_add_ext adds a copy of `ex` to `x`. It returns one on success and zero
// on failure. The caller retains ownership of `ex` and can release it
// independently of `x`.
//
// The new extension is inserted at index `loc`, shifting extensions to the
// right. If `loc` is -1 or out of bounds, the new extension is appended to the
// list.
OPENSSL_EXPORT int X509_add_ext(X509 *x, const X509_EXTENSION *ex, int loc);

// X509_add1_ext_i2d behaves like `X509V3_add1_i2d` but adds the extension to
// `x`'s extension list.
//
// WARNING: This function may return zero or -1 on error. The caller must also
// ensure `value`'s type matches `nid`. See the documentation for
// `X509V3_add1_i2d` for details.
OPENSSL_EXPORT int X509_add1_ext_i2d(X509 *x, int nid, void *value, int crit,
                                     unsigned long flags);

// X509_sign signs `x509` with `pkey` and replaces the signature algorithm and
// signature fields. It returns the length of the signature on success and zero
// on error. This function uses digest algorithm `md`, or `pkey`'s default if
// NULL. Other signing parameters use `pkey`'s defaults. To customize them, use
// `X509_sign_ctx`.
OPENSSL_EXPORT int X509_sign(X509 *x509, EVP_PKEY *pkey, const EVP_MD *md);

// X509_sign_ctx signs `x509` with `ctx` and replaces the signature algorithm
// and signature fields. It returns the length of the signature on success and
// zero on error. The signature algorithm and parameters come from `ctx`, which
// must have been initialized with `EVP_DigestSignInit`. The caller should
// configure the corresponding `EVP_PKEY_CTX` before calling this function.
//
// On success or failure, this function mutates `ctx` and resets it to the empty
// state. Caller should not rely on its contents after the function returns.
OPENSSL_EXPORT int X509_sign_ctx(X509 *x509, EVP_MD_CTX *ctx);

// i2d_re_X509_tbs serializes the TBSCertificate portion of `x509`, as described
// in `i2d_SAMPLE`.
//
// This function re-encodes the TBSCertificate and may not reflect `x509`'s
// original encoding. It may be used to manually generate a signature for a new
// certificate. To verify certificates, use `i2d_X509_tbs` instead.
//
// Unlike `i2d_X509_tbs`, this function is not `const` and thus may not be to
// use concurrently with other functions that access `x509`. It mutates `x509`
// by dropping the cached encoding. This function is intended to be used during
// certificate construction, where `x509` is still single-threaded and being
// mutated.
OPENSSL_EXPORT int i2d_re_X509_tbs(X509 *x509, uint8_t **outp);

// X509_set1_signature_algo sets `x509`'s signature algorithm to `algo` and
// returns one on success or zero on error. It updates both the signature field
// of the TBSCertificate structure, and the signatureAlgorithm field of the
// Certificate.
OPENSSL_EXPORT int X509_set1_signature_algo(X509 *x509, const X509_ALGOR *algo);

// X509_set1_signature_value sets `x509`'s signature to a copy of the `sig_len`
// bytes pointed by `sig`. It returns one on success and zero on error.
//
// Due to a specification error, X.509 certificates store signatures in ASN.1
// BIT STRINGs, but signature algorithms return byte strings rather than bit
// strings. This function creates a BIT STRING containing a whole number of
// bytes, with the bit order matching the DER encoding. This matches the
// encoding used by all X.509 signature algorithms.
OPENSSL_EXPORT int X509_set1_signature_value(X509 *x509, const uint8_t *sig,
                                             size_t sig_len);


// Auxiliary certificate properties.
//
// `X509` objects optionally maintain auxiliary properties. These are not part
// of the certificates themselves, and thus are not covered by signatures or
// preserved by the standard serialization. They are used as inputs or outputs
// to other functions in this library.

// i2d_X509_AUX marshals `x509` as a DER-encoded X.509 Certificate (RFC 5280),
// followed optionally by a separate, OpenSSL-specific structure with auxiliary
// properties. It behaves as described in `i2d_SAMPLE`.
//
// Unlike similarly-named functions, this function does not output a single
// ASN.1 element. Directly embedding the output in a larger ASN.1 structure will
// not behave correctly.
OPENSSL_EXPORT int i2d_X509_AUX(const X509 *x509, uint8_t **outp);

// d2i_X509_AUX parses up to `length` bytes from `*inp` as a DER-encoded X.509
// Certificate (RFC 5280), followed optionally by a separate, OpenSSL-specific
// structure with auxiliary properties. It behaves as described in `d2i_SAMPLE`.
//
// WARNING: Passing untrusted input to this function allows an attacker to
// control auxiliary properties. This can allow unexpected influence over the
// application if the certificate is used in a context that reads auxiliary
// properties. This includes PKCS#12 serialization, trusted certificates in
// `X509_STORE`, and callers of `X509_alias_get0` or `X509_keyid_get0`.
//
// Unlike similarly-named functions, this function does not parse a single
// ASN.1 element. Trying to parse data directly embedded in a larger ASN.1
// structure will not behave correctly.
OPENSSL_EXPORT X509 *d2i_X509_AUX(X509 **x509, const uint8_t **inp,
                                  long length);

// X509_alias_set1 sets `x509`'s alias to `len` bytes from `name`. If `name` is
// NULL, the alias is cleared instead. Aliases are not part of the certificate
// itself and will not be serialized by `i2d_X509`. If `x509` is serialized in
// a PKCS#12 structure, the friendlyName attribute (RFC 2985) will contain this
// alias.
OPENSSL_EXPORT int X509_alias_set1(X509 *x509, const uint8_t *name,
                                   ossl_ssize_t len);

// X509_keyid_set1 sets `x509`'s key ID to `len` bytes from `id`. If `id` is
// NULL, the key ID is cleared instead. Key IDs are not part of the certificate
// itself and will not be serialized by `i2d_X509`.
OPENSSL_EXPORT int X509_keyid_set1(X509 *x509, const uint8_t *id,
                                   ossl_ssize_t len);

// X509_alias_get0 looks up `x509`'s alias. If found, it sets `*out_len` to the
// alias's length and returns a pointer to a buffer containing the contents. If
// not found, it outputs the empty string by returning NULL and setting
// `*out_len` to zero.
//
// If `x509` was parsed from a PKCS#12 structure (see
// `PKCS12_get_key_and_certs`), the alias will reflect the friendlyName
// attribute (RFC 2985).
//
// WARNING: In OpenSSL, this function did not set `*out_len` when the alias was
// missing. Callers that target both OpenSSL and BoringSSL should set the value
// to zero before calling this function.
OPENSSL_EXPORT const uint8_t *X509_alias_get0(const X509 *x509, int *out_len);

// X509_keyid_get0 looks up `x509`'s key ID. If found, it sets `*out_len` to the
// key ID's length and returns a pointer to a buffer containing the contents. If
// not found, it outputs the empty string by returning NULL and setting
// `*out_len` to zero.
//
// WARNING: In OpenSSL, this function did not set `*out_len` when the alias was
// missing. Callers that target both OpenSSL and BoringSSL should set the value
// to zero before calling this function.
OPENSSL_EXPORT const uint8_t *X509_keyid_get0(const X509 *x509, int *out_len);

// X509_add1_trust_object configures `x509` as a valid trust anchor for `obj`.
// It returns one on success and zero on error. `obj` should be a certificate
// usage OID associated with an `X509_TRUST_*` constant.
//
// See `X509_VERIFY_PARAM_set_trust` for details on how this value is evaluated.
// Note this only takes effect if `x509` was configured as a trusted certificate
// via `X509_STORE`.
OPENSSL_EXPORT int X509_add1_trust_object(X509 *x509, const ASN1_OBJECT *obj);

// X509_add1_reject_object configures `x509` as distrusted for `obj`. It returns
// one on success and zero on error. `obj` should be a certificate usage OID
// associated with an `X509_TRUST_*` constant.
//
// See `X509_VERIFY_PARAM_set_trust` for details on how this value is evaluated.
// Note this only takes effect if `x509` was configured as a trusted certificate
// via `X509_STORE`.
OPENSSL_EXPORT int X509_add1_reject_object(X509 *x509, const ASN1_OBJECT *obj);

// X509_trust_clear clears the list of OIDs for which `x509` is trusted. See
// also `X509_add1_trust_object`.
OPENSSL_EXPORT void X509_trust_clear(X509 *x509);

// X509_reject_clear clears the list of OIDs for which `x509` is distrusted. See
// also `X509_add1_reject_object`.
OPENSSL_EXPORT void X509_reject_clear(X509 *x509);


// Certificate revocation lists.
//
// An `X509_CRL` object represents an X.509 certificate revocation list (CRL),
// defined in RFC 5280. A CRL is a signed list of certificates, the
// revokedCertificates field, which are no longer considered valid. Each entry
// of this list is represented with an `X509_REVOKED` object, documented in the
// "CRL entries" section below.
//
// Although an `X509_CRL` is a mutable object, mutating an `X509_CRL` or its
// `X509_REVOKED`s can give incorrect results. Callers typically obtain
// `X509_CRL`s by parsing some input with `d2i_X509_CRL`, etc. Such objects
// carry information such as the serialized TBSCertList and decoded extensions,
// which will become inconsistent when mutated.
//
// Instead, mutation functions should only be used when issuing new CRLs, as
// described in a later section.

DEFINE_STACK_OF(X509_CRL)
DEFINE_STACK_OF(X509_REVOKED)

// X509_CRL_up_ref adds one to the reference count of `crl` and returns one.
OPENSSL_EXPORT int X509_CRL_up_ref(X509_CRL *crl);

// X509_CRL_dup returns a newly-allocated copy of `crl`, or NULL on error. This
// function works by serializing the structure, so if `crl` is incomplete, it
// may fail.
OPENSSL_EXPORT X509_CRL *X509_CRL_dup(const X509_CRL *crl);

// X509_CRL_free decrements `crl`'s reference count and, if zero, releases
// memory associated with `crl`.
OPENSSL_EXPORT void X509_CRL_free(X509_CRL *crl);

// d2i_X509_CRL parses up to `len` bytes from `*inp` as a DER-encoded X.509
// CertificateList (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_CRL *d2i_X509_CRL(X509_CRL **out, const uint8_t **inp,
                                      long len);

// i2d_X509_CRL marshals `crl` as a X.509 CertificateList (RFC 5280), as
// described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_CRL(const X509_CRL *crl, uint8_t **outp);

// X509_CRL_match compares `a` and `b` and returns zero if they are equal, a
// negative number if `b` sorts after `a` and a negative number if `a` sorts
// after `b`. The sort order implemented by this function is arbitrary and does
// not reflect properties of the CRL such as expiry. Applications should not
// rely on the order itself.
//
// TODO(https://crbug.com/boringssl/355): This function works by comparing a
// cached hash of the encoded CRL. This cached hash is computed when the CRL is
// parsed, but not when mutating or issuing CRLs. This function should only be
// used with `X509_CRL` objects that were parsed from bytes and never mutated.
OPENSSL_EXPORT int X509_CRL_match(const X509_CRL *a, const X509_CRL *b);

#define X509_CRL_VERSION_1 0
#define X509_CRL_VERSION_2 1

// X509_CRL_get_version returns the numerical value of `crl`'s version, which
// will be one of the `X509_CRL_VERSION_*` constants.
OPENSSL_EXPORT long X509_CRL_get_version(const X509_CRL *crl);

// X509_CRL_get0_lastUpdate returns `crl`'s thisUpdate time. The OpenSSL API
// refers to this field as lastUpdate.
OPENSSL_EXPORT const ASN1_TIME *X509_CRL_get0_lastUpdate(const X509_CRL *crl);

// X509_CRL_get0_nextUpdate returns `crl`'s nextUpdate time, or NULL if `crl`
// has none.
OPENSSL_EXPORT const ASN1_TIME *X509_CRL_get0_nextUpdate(const X509_CRL *crl);

// X509_CRL_get_issuer returns `crl`'s issuer name. Note this function is not
// const-correct for legacy reasons.
OPENSSL_EXPORT X509_NAME *X509_CRL_get_issuer(const X509_CRL *crl);

// X509_CRL_get0_by_serial finds the entry in `crl` whose serial number is
// `serial`. If found, it sets `*out` to the entry and returns one. If not
// found, it returns zero.
//
// On success, `*out` continues to be owned by `crl`. It is an error to free or
// otherwise modify `*out`.
//
// TODO(crbug.com/42290473): Ideally `crl` would be const. It is broadly
// thread-safe, but changes the order of entries in `crl`. It cannot be called
// concurrently with `i2d_X509_CRL`.
OPENSSL_EXPORT int X509_CRL_get0_by_serial(X509_CRL *crl, X509_REVOKED **out,
                                           const ASN1_INTEGER *serial);

// X509_CRL_get0_by_cert behaves like `X509_CRL_get0_by_serial`, except it looks
// for the entry that matches `x509`.
//
// TODO(crbug.com/42290473): Ideally `crl` would be const. It is broadly
// thread-safe, but changes the order of entries in `crl`. It cannot be called
// concurrently with `i2d_X509_CRL`.
OPENSSL_EXPORT int X509_CRL_get0_by_cert(X509_CRL *crl, X509_REVOKED **out,
                                         const X509 *x509);

// X509_CRL_get_REVOKED returns the list of revoked certificates in `crl`, or
// NULL if `crl` omits it.
//
// TODO(davidben): This function was originally a macro, without clear const
// semantics. It should take a const input and give const output, but the latter
// would break existing callers. For now, we match upstream.
OPENSSL_EXPORT STACK_OF(X509_REVOKED) *X509_CRL_get_REVOKED(X509_CRL *crl);

// X509_CRL_get0_extensions returns `crl`'s extension list, or NULL if `crl`
// omits it. A CRL can have extensions on individual entries, which is
// `X509_REVOKED_get0_extensions`, or on the overall CRL, which is this
// function.
OPENSSL_EXPORT const STACK_OF(X509_EXTENSION) *X509_CRL_get0_extensions(
    const X509_CRL *crl);

// X509_CRL_get_ext_count returns the number of extensions in `x`.
OPENSSL_EXPORT int X509_CRL_get_ext_count(const X509_CRL *x);

// X509_CRL_get_ext_by_NID behaves like `X509v3_get_ext_by_NID` but searches for
// extensions in `x`.
OPENSSL_EXPORT int X509_CRL_get_ext_by_NID(const X509_CRL *x, int nid,
                                           int lastpos);

// X509_CRL_get_ext_by_OBJ behaves like `X509v3_get_ext_by_OBJ` but searches for
// extensions in `x`.
OPENSSL_EXPORT int X509_CRL_get_ext_by_OBJ(const X509_CRL *x,
                                           const ASN1_OBJECT *obj, int lastpos);

// X509_CRL_get_ext_by_critical behaves like `X509v3_get_ext_by_critical` but
// searches for extensions in `x`.
OPENSSL_EXPORT int X509_CRL_get_ext_by_critical(const X509_CRL *x, int crit,
                                                int lastpos);

// X509_CRL_get_ext returns the extension in `x` at index `loc`, or NULL if
// `loc` is out of bounds. This function returns a non-const pointer for OpenSSL
// compatibility, but callers should not mutate the result.
OPENSSL_EXPORT X509_EXTENSION *X509_CRL_get_ext(const X509_CRL *x, int loc);

// X509_CRL_get_ext_d2i behaves like `X509V3_get_d2i` but looks for the
// extension in `crl`'s extension list.
//
// WARNING: This function is difficult to use correctly. See the documentation
// for `X509V3_get_d2i` for details.
OPENSSL_EXPORT void *X509_CRL_get_ext_d2i(const X509_CRL *crl, int nid,
                                          int *out_critical, int *out_idx);

// X509_CRL_get0_signature sets `*out_sig` and `*out_alg` to the signature and
// signature algorithm of `crl`, respectively. Either output pointer may be NULL
// to ignore the value.
//
// This function outputs the outer signature algorithm, not the one in the
// TBSCertList. CRLs with mismatched signature algorithms will successfully
// parse, but they will be rejected when verifying.
OPENSSL_EXPORT void X509_CRL_get0_signature(const X509_CRL *crl,
                                            const ASN1_BIT_STRING **out_sig,
                                            const X509_ALGOR **out_alg);

// X509_CRL_get_signature_nid returns the NID corresponding to `crl`'s signature
// algorithm, or `NID_undef` if the signature algorithm does not correspond to
// a known NID.
OPENSSL_EXPORT int X509_CRL_get_signature_nid(const X509_CRL *crl);

// i2d_X509_CRL_tbs serializes the TBSCertList portion of `crl`, as described in
// `i2d_SAMPLE`.
//
// This function preserves the original encoding of the TBSCertList and may not
// reflect modifications made to `crl`. It may be used to manually verify the
// signature of an existing CRL. To generate CRLs, use `i2d_re_X509_CRL_tbs`
// instead.
OPENSSL_EXPORT int i2d_X509_CRL_tbs(const X509_CRL *crl, unsigned char **outp);

// X509_CRL_verify checks that `crl` has a valid signature by `pkey`. It returns
// one if the signature is valid and zero otherwise.
OPENSSL_EXPORT int X509_CRL_verify(const X509_CRL *crl, EVP_PKEY *pkey);


// Issuing certificate revocation lists.
//
// An `X509_CRL` object may also represent an incomplete CRL. Callers may
// construct empty `X509_CRL` objects, fill in fields individually, and finally
// sign the result. The following functions may be used for this purpose.

// X509_CRL_new returns a newly-allocated, empty `X509_CRL` object, or NULL on
// error. This object may be filled in and then signed to construct a CRL.
OPENSSL_EXPORT X509_CRL *X509_CRL_new(void);

// X509_CRL_set_version sets `crl`'s version to `version`, which should be one
// of the `X509_CRL_VERSION_*` constants. It returns one on success and zero on
// error.
//
// If unsure, use `X509_CRL_VERSION_2`. Note that, unlike certificates, CRL
// versions are only defined up to v2. Callers should not use `X509_VERSION_3`.
OPENSSL_EXPORT int X509_CRL_set_version(X509_CRL *crl, long version);

// X509_CRL_set_issuer_name sets `crl`'s issuer to a copy of `name`. It returns
// one on success and zero on error.
OPENSSL_EXPORT int X509_CRL_set_issuer_name(X509_CRL *crl,
                                            const X509_NAME *name);

// X509_CRL_set1_lastUpdate sets `crl`'s thisUpdate time to `tm`. It returns one
// on success and zero on error. The OpenSSL API refers to this field as
// lastUpdate.
OPENSSL_EXPORT int X509_CRL_set1_lastUpdate(X509_CRL *crl, const ASN1_TIME *tm);

// X509_CRL_set1_nextUpdate sets `crl`'s nextUpdate time to `tm`. It returns one
// on success and zero on error.
OPENSSL_EXPORT int X509_CRL_set1_nextUpdate(X509_CRL *crl, const ASN1_TIME *tm);

// X509_CRL_add0_revoked adds `rev` to `crl`. On success, it takes ownership of
// `rev` and returns one. On error, it returns zero. If this function fails, the
// caller retains ownership of `rev` and must release it when done.
OPENSSL_EXPORT int X509_CRL_add0_revoked(X509_CRL *crl, X509_REVOKED *rev);

// X509_CRL_sort sorts the entries in `crl` by serial number. It returns one on
// success and zero on error.
OPENSSL_EXPORT int X509_CRL_sort(X509_CRL *crl);

// X509_CRL_delete_ext removes the extension in `x` at index `loc` and returns
// the removed extension, or NULL if `loc` was out of bounds. If non-NULL, the
// caller must release the result with `X509_EXTENSION_free`.
OPENSSL_EXPORT X509_EXTENSION *X509_CRL_delete_ext(X509_CRL *x, int loc);

// X509_CRL_add_ext adds a copy of `ex` to `x`. It returns one on success and
// zero on failure. The caller retains ownership of `ex` and can release it
// independently of `x`.
//
// The new extension is inserted at index `loc`, shifting extensions to the
// right. If `loc` is -1 or out of bounds, the new extension is appended to the
// list.
OPENSSL_EXPORT int X509_CRL_add_ext(X509_CRL *x, const X509_EXTENSION *ex,
                                    int loc);

// X509_CRL_add1_ext_i2d behaves like `X509V3_add1_i2d` but adds the extension
// to `x`'s extension list.
//
// WARNING: This function may return zero or -1 on error. The caller must also
// ensure `value`'s type matches `nid`. See the documentation for
// `X509V3_add1_i2d` for details.
OPENSSL_EXPORT int X509_CRL_add1_ext_i2d(X509_CRL *x, int nid, void *value,
                                         int crit, unsigned long flags);

// X509_CRL_sign signs `crl` with `pkey` and replaces the signature algorithm
// and signature fields. It returns the length of the signature on success and
// zero on error. This function uses digest algorithm `md`, or `pkey`'s default
// if NULL. Other signing parameters use `pkey`'s defaults. To customize them,
// use `X509_CRL_sign_ctx`.
OPENSSL_EXPORT int X509_CRL_sign(X509_CRL *crl, EVP_PKEY *pkey,
                                 const EVP_MD *md);

// X509_CRL_sign_ctx signs `crl` with `ctx` and replaces the signature algorithm
// and signature fields. It returns the length of the signature on success and
// zero on error. The signature algorithm and parameters come from `ctx`, which
// must have been initialized with `EVP_DigestSignInit`. The caller should
// configure the corresponding `EVP_PKEY_CTX` before calling this function.
//
// On success or failure, this function mutates `ctx` and resets it to the empty
// state. Caller should not rely on its contents after the function returns.
OPENSSL_EXPORT int X509_CRL_sign_ctx(X509_CRL *crl, EVP_MD_CTX *ctx);

// i2d_re_X509_CRL_tbs serializes the TBSCertList portion of `crl`, as described
// in `i2d_SAMPLE`.
//
// This function re-encodes the TBSCertList and may not reflect `crl`'s original
// encoding. It may be used to manually generate a signature for a new CRL. To
// verify CRLs, use `i2d_X509_CRL_tbs` instead.
OPENSSL_EXPORT int i2d_re_X509_CRL_tbs(X509_CRL *crl, unsigned char **outp);

// X509_CRL_set1_signature_algo sets `crl`'s signature algorithm to `algo` and
// returns one on success or zero on error. It updates both the signature field
// of the TBSCertList structure, and the signatureAlgorithm field of the CRL.
OPENSSL_EXPORT int X509_CRL_set1_signature_algo(X509_CRL *crl,
                                                const X509_ALGOR *algo);

// X509_CRL_set1_signature_value sets `crl`'s signature to a copy of the
// `sig_len` bytes pointed by `sig`. It returns one on success and zero on
// error.
//
// Due to a specification error, X.509 CRLs store signatures in ASN.1 BIT
// STRINGs, but signature algorithms return byte strings rather than bit
// strings. This function creates a BIT STRING containing a whole number of
// bytes, with the bit order matching the DER encoding. This matches the
// encoding used by all X.509 signature algorithms.
OPENSSL_EXPORT int X509_CRL_set1_signature_value(X509_CRL *crl,
                                                 const uint8_t *sig,
                                                 size_t sig_len);


// CRL entries.
//
// Each entry of a CRL is represented as an `X509_REVOKED` object, which
// describes a revoked certificate by serial number.
//
// When an `X509_REVOKED` is obtained from an `X509_CRL` object, it is an error
// to mutate the object. Doing so may break `X509_CRL`'s and cause the library
// to behave incorrectly.

// X509_REVOKED_new returns a newly-allocated, empty `X509_REVOKED` object, or
// NULL on allocation error.
OPENSSL_EXPORT X509_REVOKED *X509_REVOKED_new(void);

// X509_REVOKED_free releases memory associated with `rev`.
OPENSSL_EXPORT void X509_REVOKED_free(X509_REVOKED *rev);

// d2i_X509_REVOKED parses up to `len` bytes from `*inp` as a DER-encoded X.509
// CRL entry, as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_REVOKED *d2i_X509_REVOKED(X509_REVOKED **out,
                                              const uint8_t **inp, long len);

// i2d_X509_REVOKED marshals `alg` as a DER-encoded X.509 CRL entry, as
// described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_REVOKED(const X509_REVOKED *alg, uint8_t **outp);

// X509_REVOKED_dup returns a newly-allocated copy of `rev`, or NULL on error.
// This function works by serializing the structure, so if `rev` is incomplete,
// it may fail.
OPENSSL_EXPORT X509_REVOKED *X509_REVOKED_dup(const X509_REVOKED *rev);

// X509_REVOKED_get0_serialNumber returns the serial number of the certificate
// revoked by `revoked`.
OPENSSL_EXPORT const ASN1_INTEGER *X509_REVOKED_get0_serialNumber(
    const X509_REVOKED *revoked);

// X509_REVOKED_set_serialNumber sets `revoked`'s serial number to `serial`. It
// returns one on success or zero on error.
OPENSSL_EXPORT int X509_REVOKED_set_serialNumber(X509_REVOKED *revoked,
                                                 const ASN1_INTEGER *serial);

// X509_REVOKED_get0_revocationDate returns the revocation time of the
// certificate revoked by `revoked`.
OPENSSL_EXPORT const ASN1_TIME *X509_REVOKED_get0_revocationDate(
    const X509_REVOKED *revoked);

// X509_REVOKED_set_revocationDate sets `revoked`'s revocation time to `tm`. It
// returns one on success or zero on error.
OPENSSL_EXPORT int X509_REVOKED_set_revocationDate(X509_REVOKED *revoked,
                                                   const ASN1_TIME *tm);

// X509_REVOKED_get0_extensions returns `r`'s extensions list, or NULL if `r`
// omits it. A CRL can have extensions on individual entries, which is this
// function, or on the overall CRL, which is `X509_CRL_get0_extensions`.
OPENSSL_EXPORT const STACK_OF(X509_EXTENSION) *X509_REVOKED_get0_extensions(
    const X509_REVOKED *r);

// X509_REVOKED_get_ext_count returns the number of extensions in `x`.
OPENSSL_EXPORT int X509_REVOKED_get_ext_count(const X509_REVOKED *x);

// X509_REVOKED_get_ext_by_NID behaves like `X509v3_get_ext_by_NID` but searches
// for extensions in `x`.
OPENSSL_EXPORT int X509_REVOKED_get_ext_by_NID(const X509_REVOKED *x, int nid,
                                               int lastpos);

// X509_REVOKED_get_ext_by_OBJ behaves like `X509v3_get_ext_by_OBJ` but searches
// for extensions in `x`.
OPENSSL_EXPORT int X509_REVOKED_get_ext_by_OBJ(const X509_REVOKED *x,
                                               const ASN1_OBJECT *obj,
                                               int lastpos);

// X509_REVOKED_get_ext_by_critical behaves like `X509v3_get_ext_by_critical`
// but searches for extensions in `x`.
OPENSSL_EXPORT int X509_REVOKED_get_ext_by_critical(const X509_REVOKED *x,
                                                    int crit, int lastpos);

// X509_REVOKED_get_ext returns the extension in `x` at index `loc`, or NULL if
// `loc` is out of bounds. This function returns a non-const pointer for OpenSSL
// compatibility, but callers should not mutate the result.
OPENSSL_EXPORT X509_EXTENSION *X509_REVOKED_get_ext(const X509_REVOKED *x,
                                                    int loc);

// X509_REVOKED_delete_ext removes the extension in `x` at index `loc` and
// returns the removed extension, or NULL if `loc` was out of bounds. If
// non-NULL, the caller must release the result with `X509_EXTENSION_free`.
OPENSSL_EXPORT X509_EXTENSION *X509_REVOKED_delete_ext(X509_REVOKED *x,
                                                       int loc);

// X509_REVOKED_add_ext adds a copy of `ex` to `x`. It returns one on success
// and zero on failure. The caller retains ownership of `ex` and can release it
// independently of `x`.
//
// The new extension is inserted at index `loc`, shifting extensions to the
// right. If `loc` is -1 or out of bounds, the new extension is appended to the
// list.
OPENSSL_EXPORT int X509_REVOKED_add_ext(X509_REVOKED *x,
                                        const X509_EXTENSION *ex, int loc);

// X509_REVOKED_get_ext_d2i behaves like `X509V3_get_d2i` but looks for the
// extension in `revoked`'s extension list.
//
// WARNING: This function is difficult to use correctly. See the documentation
// for `X509V3_get_d2i` for details.
OPENSSL_EXPORT void *X509_REVOKED_get_ext_d2i(const X509_REVOKED *revoked,
                                              int nid, int *out_critical,
                                              int *out_idx);

// X509_REVOKED_add1_ext_i2d behaves like `X509V3_add1_i2d` but adds the
// extension to `x`'s extension list.
//
// WARNING: This function may return zero or -1 on error. The caller must also
// ensure `value`'s type matches `nid`. See the documentation for
// `X509V3_add1_i2d` for details.
OPENSSL_EXPORT int X509_REVOKED_add1_ext_i2d(X509_REVOKED *x, int nid,
                                             void *value, int crit,
                                             unsigned long flags);


// Certificate requests.
//
// An `X509_REQ` represents a PKCS #10 certificate request (RFC 2986). These are
// also referred to as certificate signing requests or CSRs. CSRs are a common
// format used to request a certificate from a CA.
//
// Although an `X509_REQ` is a mutable object, mutating an `X509_REQ` can give
// incorrect results. Callers typically obtain `X509_REQ`s by parsing some input
// with `d2i_X509_REQ`, etc. Such objects carry information such as the
// serialized CertificationRequestInfo, which will become inconsistent when
// mutated.
//
// Instead, mutation functions should only be used when issuing new CRLs, as
// described in a later section.

// X509_REQ_dup returns a newly-allocated copy of `req`, or NULL on error. This
// function works by serializing the structure, so if `req` is incomplete, it
// may fail.
OPENSSL_EXPORT X509_REQ *X509_REQ_dup(const X509_REQ *req);

// X509_REQ_free releases memory associated with `req`.
OPENSSL_EXPORT void X509_REQ_free(X509_REQ *req);

// d2i_X509_REQ parses up to `len` bytes from `*inp` as a DER-encoded
// CertificateRequest (RFC 2986), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_REQ *d2i_X509_REQ(X509_REQ **out, const uint8_t **inp,
                                      long len);

// i2d_X509_REQ marshals `req` as a CertificateRequest (RFC 2986), as described
// in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_REQ(const X509_REQ *req, uint8_t **outp);

// X509_REQ_VERSION_1 is the version constant for `X509_REQ` objects. No other
// versions are defined.
#define X509_REQ_VERSION_1 0

// X509_REQ_get_version returns the numerical value of `req`'s version. This
// will always be `X509_REQ_VERSION_1` for valid CSRs. For compatibility,
// `d2i_X509_REQ` also accepts some invalid version numbers, in which case this
// function may return other values.
OPENSSL_EXPORT long X509_REQ_get_version(const X509_REQ *req);

// X509_REQ_get_subject_name returns `req`'s subject name. Note this function is
// not const-correct for legacy reasons.
OPENSSL_EXPORT X509_NAME *X509_REQ_get_subject_name(const X509_REQ *req);

// X509_REQ_get0_pubkey returns `req`'s public key as an `EVP_PKEY`, or NULL if
// the public key was unsupported or could not be decoded. The `EVP_PKEY` is
// cached in `req`, so callers must not mutate the result.
OPENSSL_EXPORT EVP_PKEY *X509_REQ_get0_pubkey(const X509_REQ *req);

// X509_REQ_get_pubkey behaves like `X509_REQ_get0_pubkey` but increments the
// reference count on the `EVP_PKEY`. The caller must release the result with
// `EVP_PKEY_free` when done. The `EVP_PKEY` is cached in `req`, so callers must
// not mutate the result.
OPENSSL_EXPORT EVP_PKEY *X509_REQ_get_pubkey(const X509_REQ *req);

// X509_REQ_check_private_key returns one if `req`'s public key matches `pkey`
// and zero otherwise.
OPENSSL_EXPORT int X509_REQ_check_private_key(const X509_REQ *req,
                                              const EVP_PKEY *pkey);

// X509_REQ_get_attr_count returns the number of attributes in `req`.
OPENSSL_EXPORT int X509_REQ_get_attr_count(const X509_REQ *req);

// X509_REQ_get_attr returns the attribute at index `loc` in `req`, or NULL if
// out of bounds.
OPENSSL_EXPORT X509_ATTRIBUTE *X509_REQ_get_attr(const X509_REQ *req, int loc);

// X509_REQ_get_attr_by_NID returns the index of the attribute in `req` of type
// `nid`, or a negative number if not found. If found, callers can use
// `X509_REQ_get_attr` to look up the attribute by index.
//
// If `lastpos` is non-negative, it begins searching at `lastpos` + 1. Callers
// can thus loop over all matching attributes by first passing -1 and then
// passing the previously-returned value until no match is returned.
OPENSSL_EXPORT int X509_REQ_get_attr_by_NID(const X509_REQ *req, int nid,
                                            int lastpos);

// X509_REQ_get_attr_by_OBJ behaves like `X509_REQ_get_attr_by_NID` but looks
// for attributes of type `obj`.
OPENSSL_EXPORT int X509_REQ_get_attr_by_OBJ(const X509_REQ *req,
                                            const ASN1_OBJECT *obj,
                                            int lastpos);

// X509_REQ_extension_nid returns one if `nid` is a supported CSR attribute type
// for carrying extensions and zero otherwise. The supported types are
// `NID_ext_req` (pkcs-9-at-extensionRequest from RFC 2985) and `NID_ms_ext_req`
// (a Microsoft szOID_CERT_EXTENSIONS variant).
OPENSSL_EXPORT int X509_REQ_extension_nid(int nid);

// X509_REQ_get_extensions decodes the most preferred list of requested
// extensions in `req` and returns a newly-allocated `STACK_OF(X509_EXTENSION)`
// containing the result. It returns NULL on error, or if `req` did not request
// extensions.
//
// CSRs do not store extensions directly. Instead there are attribute types
// which are defined to hold extensions. See `X509_REQ_extension_nid`. This
// function supports both pkcs-9-at-extensionRequest from RFC 2985 and the
// Microsoft szOID_CERT_EXTENSIONS variant. If both are present,
// pkcs-9-at-extensionRequest is preferred.
OPENSSL_EXPORT STACK_OF(X509_EXTENSION) *X509_REQ_get_extensions(
    const X509_REQ *req);

// X509_REQ_get0_signature sets `*out_sig` and `*out_alg` to the signature and
// signature algorithm of `req`, respectively. Either output pointer may be NULL
// to ignore the value.
OPENSSL_EXPORT void X509_REQ_get0_signature(const X509_REQ *req,
                                            const ASN1_BIT_STRING **out_sig,
                                            const X509_ALGOR **out_alg);

// X509_REQ_get_signature_nid returns the NID corresponding to `req`'s signature
// algorithm, or `NID_undef` if the signature algorithm does not correspond to
// a known NID.
OPENSSL_EXPORT int X509_REQ_get_signature_nid(const X509_REQ *req);

// X509_REQ_verify checks that `req` has a valid signature by `pkey`. It returns
// one if the signature is valid and zero otherwise.
OPENSSL_EXPORT int X509_REQ_verify(const X509_REQ *req, EVP_PKEY *pkey);

// X509_REQ_get1_email returns a newly-allocated list of NUL-terminated strings
// containing all email addresses in `req`'s subject and all rfc822name names
// in `req`'s subject alternative names. The subject alternative names extension
// is extracted from the result of `X509_REQ_get_extensions`. Email addresses
// which contain embedded NUL bytes are skipped. The results are returned in an
// arbitrary order.
//
// On error, or if there are no such email addresses, it returns NULL. When
// done, the caller must release the result with `X509_email_free`.
OPENSSL_EXPORT STACK_OF(OPENSSL_STRING) *X509_REQ_get1_email(
    const X509_REQ *req);


// Issuing certificate requests.
//
// An `X509_REQ` object may also represent an incomplete CSR. Callers may
// construct empty `X509_REQ` objects, fill in fields individually, and finally
// sign the result. The following functions may be used for this purpose.

// X509_REQ_new returns a newly-allocated, empty `X509_REQ` object, or NULL on
// error. This object may be filled in and then signed to construct a CSR.
OPENSSL_EXPORT X509_REQ *X509_REQ_new(void);

// X509_REQ_set_version sets `req`'s version to `version`, which should be
// `X509_REQ_VERSION_1`. It returns one on success and zero on error.
//
// The only defined CSR version is `X509_REQ_VERSION_1`, so there is no need to
// call this function.
OPENSSL_EXPORT int X509_REQ_set_version(X509_REQ *req, long version);

// X509_REQ_set_subject_name sets `req`'s subject to a copy of `name`. It
// returns one on success and zero on error.
OPENSSL_EXPORT int X509_REQ_set_subject_name(X509_REQ *req, X509_NAME *name);

// X509_REQ_set_pubkey sets `req`'s public key to `pkey`. It returns one on
// success and zero on error. This function does not take ownership of `pkey`
// and internally copies and updates reference counts as needed.
OPENSSL_EXPORT int X509_REQ_set_pubkey(X509_REQ *req, EVP_PKEY *pkey);

// X509_REQ_delete_attr removes the attribute at index `loc` in `req`. It
// returns the removed attribute to the caller, or NULL if `loc` was out of
// bounds. If non-NULL, the caller must release the result with
// `X509_ATTRIBUTE_free` when done. It is also safe, but not necessary, to call
// `X509_ATTRIBUTE_free` if the result is NULL.
OPENSSL_EXPORT X509_ATTRIBUTE *X509_REQ_delete_attr(X509_REQ *req, int loc);

// X509_REQ_add1_attr appends a copy of `attr` to `req`'s list of attributes. It
// returns one on success and zero on error.
OPENSSL_EXPORT int X509_REQ_add1_attr(X509_REQ *req,
                                      const X509_ATTRIBUTE *attr);

// X509_REQ_add1_attr_by_OBJ appends a new attribute to `req` with type `obj`.
// It returns one on success and zero on error. The value is determined by
// `X509_ATTRIBUTE_set1_data`.
//
// WARNING: The interpretation of `attrtype`, `data`, and `len` is complex and
// error-prone. See `X509_ATTRIBUTE_set1_data` for details.
OPENSSL_EXPORT int X509_REQ_add1_attr_by_OBJ(X509_REQ *req,
                                             const ASN1_OBJECT *obj,
                                             int attrtype,
                                             const unsigned char *data,
                                             int len);

// X509_REQ_add1_attr_by_NID behaves like `X509_REQ_add1_attr_by_OBJ` except the
// attribute type is determined by `nid`.
OPENSSL_EXPORT int X509_REQ_add1_attr_by_NID(X509_REQ *req, int nid,
                                             int attrtype,
                                             const unsigned char *data,
                                             int len);

// X509_REQ_add1_attr_by_txt behaves like `X509_REQ_add1_attr_by_OBJ` except the
// attribute type is determined by calling `OBJ_txt2obj` with `attrname`.
OPENSSL_EXPORT int X509_REQ_add1_attr_by_txt(X509_REQ *req,
                                             const char *attrname, int attrtype,
                                             const unsigned char *data,
                                             int len);

// X509_REQ_add_extensions_nid adds an attribute to `req` of type `nid`, to
// request the certificate extensions in `exts`. It returns one on success and
// zero on error. `nid` should be `NID_ext_req` or `NID_ms_ext_req`.
OPENSSL_EXPORT int X509_REQ_add_extensions_nid(
    X509_REQ *req, const STACK_OF(X509_EXTENSION) *exts, int nid);

// X509_REQ_add_extensions behaves like `X509_REQ_add_extensions_nid`, using the
// standard `NID_ext_req` for the attribute type.
OPENSSL_EXPORT int X509_REQ_add_extensions(
    X509_REQ *req, const STACK_OF(X509_EXTENSION) *exts);

// X509_REQ_sign signs `req` with `pkey` and replaces the signature algorithm
// and signature fields. It returns the length of the signature on success and
// zero on error. This function uses digest algorithm `md`, or `pkey`'s default
// if NULL. Other signing parameters use `pkey`'s defaults. To customize them,
// use `X509_REQ_sign_ctx`.
OPENSSL_EXPORT int X509_REQ_sign(X509_REQ *req, EVP_PKEY *pkey,
                                 const EVP_MD *md);

// X509_REQ_sign_ctx signs `req` with `ctx` and replaces the signature algorithm
// and signature fields. It returns the length of the signature on success and
// zero on error. The signature algorithm and parameters come from `ctx`, which
// must have been initialized with `EVP_DigestSignInit`. The caller should
// configure the corresponding `EVP_PKEY_CTX` before calling this function.
//
// On success or failure, this function mutates `ctx` and resets it to the empty
// state. Caller should not rely on its contents after the function returns.
OPENSSL_EXPORT int X509_REQ_sign_ctx(X509_REQ *req, EVP_MD_CTX *ctx);

// i2d_re_X509_REQ_tbs serializes the CertificationRequestInfo (see RFC 2986)
// portion of `req`, as described in `i2d_SAMPLE`.
//
// This function re-encodes the CertificationRequestInfo and may not reflect
// `req`'s original encoding. It may be used to manually generate a signature
// for a new certificate request.
OPENSSL_EXPORT int i2d_re_X509_REQ_tbs(X509_REQ *req, uint8_t **outp);

// X509_REQ_set1_signature_algo sets `req`'s signature algorithm to `algo` and
// returns one on success or zero on error.
OPENSSL_EXPORT int X509_REQ_set1_signature_algo(X509_REQ *req,
                                                const X509_ALGOR *algo);

// X509_REQ_set1_signature_value sets `req`'s signature to a copy of the
// `sig_len` bytes pointed by `sig`. It returns one on success and zero on
// error.
//
// Due to a specification error, PKCS#10 certificate requests store signatures
// in ASN.1 BIT STRINGs, but signature algorithms return byte strings rather
// than bit strings. This function creates a BIT STRING containing a whole
// number of bytes, with the bit order matching the DER encoding. This matches
// the encoding used by all X.509 signature algorithms.
OPENSSL_EXPORT int X509_REQ_set1_signature_value(X509_REQ *req,
                                                 const uint8_t *sig,
                                                 size_t sig_len);


// Names.
//
// An `X509_NAME` represents an X.509 Name structure (RFC 5280). X.509 names are
// a complex, hierarchical structure over a collection of attributes. Each name
// is sequence of relative distinguished names (RDNs), decreasing in
// specificity. For example, the first RDN may specify the country, while the
// next RDN may specify a locality. Each RDN is, itself, a set of attributes.
// Having more than one attribute in an RDN is uncommon, but possible. Within an
// RDN, attributes have the same level in specificity. Attribute types are
// OBJECT IDENTIFIERs. This determines the ASN.1 type of the value, which is
// commonly a string but may be other types.
//
// The `X509_NAME` representation flattens this two-level structure into a
// single list of attributes. Each attribute is stored in an `X509_NAME_ENTRY`,
// with also maintains the index of the RDN it is part of, accessible via
// `X509_NAME_ENTRY_set`. This can be used to recover the two-level structure.
//
// X.509 names are largely vestigial. Historically, DNS names were parsed out of
// the subject's common name attribute, but this is deprecated and has since
// moved to the subject alternative name extension. In modern usage, X.509 names
// are primarily opaque identifiers to link a certificate with its issuer.

DEFINE_STACK_OF(X509_NAME_ENTRY)
DEFINE_STACK_OF(X509_NAME)

// X509_NAME is an `ASN1_ITEM` whose ASN.1 type is X.509 Name (RFC 5280) and C
// type is `X509_NAME*`.
DECLARE_ASN1_ITEM(X509_NAME)

// X509_NAME_new returns a new, empty `X509_NAME`, or NULL on error.
OPENSSL_EXPORT X509_NAME *X509_NAME_new(void);

// X509_NAME_free releases memory associated with `name`.
OPENSSL_EXPORT void X509_NAME_free(X509_NAME *name);

// d2i_X509_NAME parses up to `len` bytes from `*inp` as a DER-encoded X.509
// Name (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_NAME *d2i_X509_NAME(X509_NAME **out, const uint8_t **inp,
                                        long len);

// i2d_X509_NAME marshals `in` as a DER-encoded X.509 Name (RFC 5280), as
// described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_NAME(const X509_NAME *in, uint8_t **outp);

// X509_NAME_dup returns a newly-allocated copy of `name`, or NULL on error.
OPENSSL_EXPORT X509_NAME *X509_NAME_dup(const X509_NAME *name);

// X509_NAME_cmp compares `a` and `b`'s canonicalized forms. It returns zero if
// they are equal, one if `a` sorts after `b`, -1 if `b` sorts after `a`, and -2
// on error.
//
// TODO(https://crbug.com/boringssl/355): The -2 return is very inconvenient to
// pass to a sorting function. Can we make this infallible? In the meantime,
// prefer to use this function only for equality checks rather than comparisons.
// Although even the library itself passes this to a sorting function.
OPENSSL_EXPORT int X509_NAME_cmp(const X509_NAME *a, const X509_NAME *b);

// X509_NAME_get0_der marshals `name` as a DER-encoded X.509 Name (RFC 5280). On
// success, it returns one and sets `*out_der` and `*out_der_len` to a buffer
// containing the result. Otherwise, it returns zero. `*out_der` is owned by
// `name` and must not be freed by the caller. It is invalidated after `name` is
// mutated or freed.
OPENSSL_EXPORT int X509_NAME_get0_der(const X509_NAME *name,
                                      const uint8_t **out_der,
                                      size_t *out_der_len);

// X509_NAME_set makes a copy of `name`. On success, it frees `*xn`, sets `*xn`
// to the copy, and returns one. Otherwise, it returns zero.
OPENSSL_EXPORT int X509_NAME_set(X509_NAME **xn, const X509_NAME *name);

// X509_NAME_entry_count returns the number of entries in `name`.
OPENSSL_EXPORT int X509_NAME_entry_count(const X509_NAME *name);

// X509_NAME_get_index_by_NID returns the zero-based index of the first
// attribute in `name` with type `nid`, or -1 if there is none. `nid` should be
// one of the `NID_*` constants. If `lastpos` is non-negative, it begins
// searching at `lastpos+1`. To search all attributes, pass in -1, not zero.
//
// Indices from this function refer to `X509_NAME`'s flattened representation.
OPENSSL_EXPORT int X509_NAME_get_index_by_NID(const X509_NAME *name, int nid,
                                              int lastpos);

// X509_NAME_get_index_by_OBJ behaves like `X509_NAME_get_index_by_NID` but
// looks for attributes with type `obj`.
OPENSSL_EXPORT int X509_NAME_get_index_by_OBJ(const X509_NAME *name,
                                              const ASN1_OBJECT *obj,
                                              int lastpos);

// X509_NAME_get_entry returns the attribute in `name` at index `loc`, or NULL
// if `loc` is out of range. `loc` is interpreted using `X509_NAME`'s flattened
// representation. This function returns a non-const pointer for OpenSSL
// compatibility, but callers should not mutate the result. Doing so will break
// internal invariants in the library.
OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_get_entry(const X509_NAME *name,
                                                    int loc);

// X509_NAME_delete_entry removes and returns the attribute in `name` at index
// `loc`, or NULL if `loc` is out of range. `loc` is interpreted using
// `X509_NAME`'s flattened representation. If the attribute is found, the caller
// is responsible for releasing the result with `X509_NAME_ENTRY_free`.
//
// This function will internally update RDN indices (see `X509_NAME_ENTRY_set`)
// so they continue to be consecutive.
OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_delete_entry(X509_NAME *name,
                                                       int loc);

// X509_NAME_add_entry adds a copy of `entry` to `name` and returns one on
// success or zero on error. If `loc` is -1, the entry is appended to `name`.
// Otherwise, it is inserted at index `loc`. If `set` is -1, the entry is added
// to the previous entry's RDN. If it is 0, the entry becomes a singleton RDN.
// If 1, it is added to next entry's RDN.
//
// This function will internally update RDN indices (see `X509_NAME_ENTRY_set`)
// so they continue to be consecutive.
OPENSSL_EXPORT int X509_NAME_add_entry(X509_NAME *name,
                                       const X509_NAME_ENTRY *entry, int loc,
                                       int set);

// X509_NAME_add_entry_by_OBJ adds a new entry to `name` and returns one on
// success or zero on error. The entry's attribute type is `obj`. The entry's
// attribute value is determined by `type`, `bytes`, and `len`, as in
// `X509_NAME_ENTRY_set_data`. The entry's position is determined by `loc` and
// `set` as in `X509_NAME_add_entry`.
OPENSSL_EXPORT int X509_NAME_add_entry_by_OBJ(X509_NAME *name,
                                              const ASN1_OBJECT *obj, int type,
                                              const uint8_t *bytes,
                                              ossl_ssize_t len, int loc,
                                              int set);

// X509_NAME_add_entry_by_NID behaves like `X509_NAME_add_entry_by_OBJ` but sets
// the entry's attribute type to `nid`, which should be one of the `NID_*`
// constants.
OPENSSL_EXPORT int X509_NAME_add_entry_by_NID(X509_NAME *name, int nid,
                                              int type, const uint8_t *bytes,
                                              ossl_ssize_t len, int loc,
                                              int set);

// X509_NAME_add_entry_by_txt behaves like `X509_NAME_add_entry_by_OBJ` but sets
// the entry's attribute type to `field`, which is passed to `OBJ_txt2obj`.
OPENSSL_EXPORT int X509_NAME_add_entry_by_txt(X509_NAME *name,
                                              const char *field, int type,
                                              const uint8_t *bytes,
                                              ossl_ssize_t len, int loc,
                                              int set);

// X509_NAME_ENTRY_new returns a new, empty `X509_NAME_ENTRY`, or NULL on error.
OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_ENTRY_new(void);

// X509_NAME_ENTRY_free releases memory associated with `entry`.
OPENSSL_EXPORT void X509_NAME_ENTRY_free(X509_NAME_ENTRY *entry);

// X509_NAME_ENTRY_dup returns a newly-allocated copy of `entry`, or NULL on
// error.
OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_ENTRY_dup(
    const X509_NAME_ENTRY *entry);

// X509_NAME_ENTRY_get_object returns `entry`'s attribute type. This function
// returns a non-const pointer for OpenSSL compatibility, but callers should not
// mutate the result. Doing so will break internal invariants in the library.
OPENSSL_EXPORT ASN1_OBJECT *X509_NAME_ENTRY_get_object(
    const X509_NAME_ENTRY *entry);

// X509_NAME_ENTRY_set_object sets `entry`'s attribute type to `obj`. It returns
// one on success and zero on error.
OPENSSL_EXPORT int X509_NAME_ENTRY_set_object(X509_NAME_ENTRY *entry,
                                              const ASN1_OBJECT *obj);

// X509_NAME_ENTRY_get_data returns `entry`'s attribute value, represented as an
// `ASN1_STRING`. This value may have any ASN.1 type, so callers must check the
// type before interpreting the contents. This function returns a non-const
// pointer for OpenSSL compatibility, but callers should not mutate the result.
// Doing so will break internal invariants in the library.
//
// See `ASN1_STRING` for how values are represented in this library. Where a
// specific `ASN1_STRING` representation exists, that representation is used.
// Otherwise, the `V_ASN1_OTHER` representation is used. Note that NULL, OBJECT
// IDENTIFIER, and BOOLEAN attribute values are represented as `V_ASN1_OTHER`,
// because their usual representation in this library is not
// `ASN1_STRING`-compatible.
OPENSSL_EXPORT ASN1_STRING *X509_NAME_ENTRY_get_data(
    const X509_NAME_ENTRY *entry);

// X509_NAME_ENTRY_set_data sets `entry`'s value to `len` bytes from `bytes`. It
// returns one on success and zero on error. If `len` is -1, `bytes` must be a
// NUL-terminated C string and the length is determined by `strlen`. `bytes` is
// converted to an ASN.1 type as follows:
//
// If `type` is a `MBSTRING_*` constant, the value is an ASN.1 string. The
// string is determined by decoding `bytes` in the encoding specified by `type`,
// and then re-encoding it in a form appropriate for `entry`'s attribute type.
// See `ASN1_STRING_set_by_NID` for details.
//
// Otherwise, the value is an `ASN1_STRING` with type `type` and value `bytes`.
// See `ASN1_STRING` for how to format ASN.1 types as an `ASN1_STRING`. If
// `type` is `V_ASN1_UNDEF` the previous `ASN1_STRING` type is reused.
OPENSSL_EXPORT int X509_NAME_ENTRY_set_data(X509_NAME_ENTRY *entry, int type,
                                            const uint8_t *bytes,
                                            ossl_ssize_t len);

// X509_NAME_ENTRY_set returns the zero-based index of the RDN which contains
// `entry`. Consecutive entries with the same index are part of the same RDN.
OPENSSL_EXPORT int X509_NAME_ENTRY_set(const X509_NAME_ENTRY *entry);

// X509_NAME_ENTRY_create_by_OBJ creates a new `X509_NAME_ENTRY` with attribute
// type `obj`. The attribute value is determined from `type`, `bytes`, and `len`
// as in `X509_NAME_ENTRY_set_data`. It returns the `X509_NAME_ENTRY` on success
// and NULL on error.
//
// If `out` is non-NULL and `*out` is NULL, it additionally sets `*out` to the
// result on success. If both `out` and `*out` are non-NULL, it updates the
// object at `*out` instead of allocating a new one.
OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_ENTRY_create_by_OBJ(
    X509_NAME_ENTRY **out, const ASN1_OBJECT *obj, int type,
    const uint8_t *bytes, ossl_ssize_t len);

// X509_NAME_ENTRY_create_by_NID behaves like `X509_NAME_ENTRY_create_by_OBJ`
// except the attribute type is `nid`, which should be one of the `NID_*`
// constants.
OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_ENTRY_create_by_NID(
    X509_NAME_ENTRY **out, int nid, int type, const uint8_t *bytes,
    ossl_ssize_t len);

// X509_NAME_ENTRY_create_by_txt behaves like `X509_NAME_ENTRY_create_by_OBJ`
// except the attribute type is `field`, which is passed to `OBJ_txt2obj`.
OPENSSL_EXPORT X509_NAME_ENTRY *X509_NAME_ENTRY_create_by_txt(
    X509_NAME_ENTRY **out, const char *field, int type, const uint8_t *bytes,
    ossl_ssize_t len);


// Public keys.
//
// X.509 encodes public keys as SubjectPublicKeyInfo (RFC 5280), sometimes
// referred to as SPKI. These are represented in this library by `X509_PUBKEY`.

// X509_PUBKEY_new returns a newly-allocated, empty `X509_PUBKEY` object, or
// NULL on error.
OPENSSL_EXPORT X509_PUBKEY *X509_PUBKEY_new(void);

// X509_PUBKEY_free releases memory associated with `key`.
OPENSSL_EXPORT void X509_PUBKEY_free(X509_PUBKEY *key);

// d2i_X509_PUBKEY parses up to `len` bytes from `*inp` as a DER-encoded
// SubjectPublicKeyInfo, as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_PUBKEY *d2i_X509_PUBKEY(X509_PUBKEY **out,
                                            const uint8_t **inp, long len);

// i2d_X509_PUBKEY marshals `key` as a DER-encoded SubjectPublicKeyInfo, as
// described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_PUBKEY(const X509_PUBKEY *key, uint8_t **outp);

// X509_PUBKEY_set serializes `pkey` into a newly-allocated `X509_PUBKEY`
// structure. On success, it frees `*x` if non-NULL, then sets `*x` to the new
// object, and returns one. Otherwise, it returns zero.
OPENSSL_EXPORT int X509_PUBKEY_set(X509_PUBKEY **x, EVP_PKEY *pkey);

// X509_PUBKEY_get0 returns `key` as an `EVP_PKEY`, or NULL if `key` either
// could not be parsed or is an unrecognized algorithm. The `EVP_PKEY` is cached
// in `key`, so callers must not mutate the result.
OPENSSL_EXPORT EVP_PKEY *X509_PUBKEY_get0(const X509_PUBKEY *key);

// X509_PUBKEY_get behaves like `X509_PUBKEY_get0` but increments the reference
// count on the `EVP_PKEY`. The caller must release the result with
// `EVP_PKEY_free` when done. The `EVP_PKEY` is cached in `key`, so callers must
// not mutate the result.
OPENSSL_EXPORT EVP_PKEY *X509_PUBKEY_get(const X509_PUBKEY *key);

// X509_PUBKEY_set0_param sets `pub` to a key with AlgorithmIdentifier
// determined by `obj`, `param_type`, and `param_value`, and an encoded
// public key of `key`. On success, it gives `pub` ownership of all the other
// parameters and returns one. Otherwise, it returns zero. `key` must have been
// allocated by `OPENSSL_malloc`. `obj` and, if applicable, `param_value` must
// not be freed after a successful call, and must have been allocated in a
// manner compatible with `ASN1_OBJECT_free` or `ASN1_STRING_free`.
//
// `obj`, `param_type`, and `param_value` are interpreted as in
// `X509_ALGOR_set0`. See `X509_ALGOR_set0` for details.
OPENSSL_EXPORT int X509_PUBKEY_set0_param(X509_PUBKEY *pub, ASN1_OBJECT *obj,
                                          int param_type, void *param_value,
                                          uint8_t *key, int key_len);

// X509_PUBKEY_get0_param outputs fields of `pub` and returns one. If `out_obj`
// is not NULL, it sets `*out_obj` to AlgorithmIdentifier's OID. If `out_key`
// is not NULL, it sets `*out_key` and `*out_key_len` to the encoded public key.
// If `out_alg` is not NULL, it sets `*out_alg` to the AlgorithmIdentifier.
//
// All pointers outputted by this function are internal to `pub` and must not be
// freed by the caller. Additionally, although some outputs are non-const,
// callers must not mutate the resulting objects.
//
// Note: X.509 SubjectPublicKeyInfo structures store the encoded public key as a
// BIT STRING. `*out_key` and `*out_key_len` will silently pad the key with zero
// bits if `pub` did not contain a whole number of bytes. Use
// `X509_PUBKEY_get0_public_key` to preserve this information.
OPENSSL_EXPORT int X509_PUBKEY_get0_param(ASN1_OBJECT **out_obj,
                                          const uint8_t **out_key,
                                          int *out_key_len,
                                          X509_ALGOR **out_alg,
                                          X509_PUBKEY *pub);

// X509_PUBKEY_get0_public_key returns `pub`'s encoded public key.
OPENSSL_EXPORT const ASN1_BIT_STRING *X509_PUBKEY_get0_public_key(
    const X509_PUBKEY *pub);


// Extensions.
//
// X.509 certificates and CRLs may contain a list of extensions (RFC 5280).
// Extensions have a type, specified by an object identifier (`ASN1_OBJECT`) and
// a byte string value, which should a DER-encoded structure whose type is
// determined by the extension type. This library represents extensions with the
// `X509_EXTENSION` type.

// X509_EXTENSION is an `ASN1_ITEM` whose ASN.1 type is X.509 Extension (RFC
// 5280) and C type is `X509_EXTENSION*`.
DECLARE_ASN1_ITEM(X509_EXTENSION)

// X509_EXTENSION_new returns a newly-allocated, empty `X509_EXTENSION` object
// or NULL on error.
OPENSSL_EXPORT X509_EXTENSION *X509_EXTENSION_new(void);

// X509_EXTENSION_free releases memory associated with `ex`.
OPENSSL_EXPORT void X509_EXTENSION_free(X509_EXTENSION *ex);

// d2i_X509_EXTENSION parses up to `len` bytes from `*inp` as a DER-encoded
// X.509 Extension (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_EXTENSION *d2i_X509_EXTENSION(X509_EXTENSION **out,
                                                  const uint8_t **inp,
                                                  long len);

// i2d_X509_EXTENSION marshals `ex` as a DER-encoded X.509 Extension (RFC
// 5280), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_EXTENSION(const X509_EXTENSION *ex, uint8_t **outp);

// X509_EXTENSION_dup returns a newly-allocated copy of `ex`, or NULL on error.
// This function works by serializing the structure, so if `ex` is incomplete,
// it may fail.
OPENSSL_EXPORT X509_EXTENSION *X509_EXTENSION_dup(const X509_EXTENSION *ex);

// X509_EXTENSION_create_by_NID creates a new `X509_EXTENSION` with type `nid`,
// value `data`, and critical bit `crit`. It returns an `X509_EXTENSION` on
// success, and NULL on error. `nid` should be a `NID_*` constant.
//
// If `ex` and `*ex` are both non-NULL, `*ex` is used to hold the result,
// otherwise a new object is allocated. If `ex` is non-NULL and `*ex` is NULL,
// the function sets `*ex` to point to the newly allocated result, in addition
// to returning the result.
OPENSSL_EXPORT X509_EXTENSION *X509_EXTENSION_create_by_NID(
    X509_EXTENSION **ex, int nid, int crit, const ASN1_OCTET_STRING *data);

// X509_EXTENSION_create_by_OBJ behaves like `X509_EXTENSION_create_by_NID`, but
// the extension type is determined by an `ASN1_OBJECT`.
OPENSSL_EXPORT X509_EXTENSION *X509_EXTENSION_create_by_OBJ(
    X509_EXTENSION **ex, const ASN1_OBJECT *obj, int crit,
    const ASN1_OCTET_STRING *data);

// X509_EXTENSION_get_object returns `ex`'s extension type. This function
// returns a non-const pointer for OpenSSL compatibility, but callers should not
// mutate the result.
OPENSSL_EXPORT ASN1_OBJECT *X509_EXTENSION_get_object(const X509_EXTENSION *ex);

// X509_EXTENSION_get_data returns `ne`'s extension value. This function returns
// a non-const pointer for OpenSSL compatibility, but callers should not mutate
// the result.
OPENSSL_EXPORT ASN1_OCTET_STRING *X509_EXTENSION_get_data(
    const X509_EXTENSION *ne);

// X509_EXTENSION_get_critical returns one if `ex` is critical and zero
// otherwise.
OPENSSL_EXPORT int X509_EXTENSION_get_critical(const X509_EXTENSION *ex);

// X509_EXTENSION_set_object sets `ex`'s extension type to `obj`. It returns one
// on success and zero on error.
OPENSSL_EXPORT int X509_EXTENSION_set_object(X509_EXTENSION *ex,
                                             const ASN1_OBJECT *obj);

// X509_EXTENSION_set_critical sets `ex` to critical if `crit` is non-zero and
// to non-critical if `crit` is zero.
OPENSSL_EXPORT int X509_EXTENSION_set_critical(X509_EXTENSION *ex, int crit);

// X509_EXTENSION_set_data sets `ex`'s extension value to a copy of `data`. It
// returns one on success and zero on error.
OPENSSL_EXPORT int X509_EXTENSION_set_data(X509_EXTENSION *ex,
                                           const ASN1_OCTET_STRING *data);


// Extension lists.
//
// The following functions manipulate lists of extensions. Most of them have
// corresponding functions on the containing `X509`, `X509_CRL`, or
// `X509_REVOKED`.

DEFINE_STACK_OF(X509_EXTENSION)
typedef STACK_OF(X509_EXTENSION) X509_EXTENSIONS;

// d2i_X509_EXTENSIONS parses up to `len` bytes from `*inp` as a DER-encoded
// SEQUENCE OF Extension (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_EXTENSIONS *d2i_X509_EXTENSIONS(X509_EXTENSIONS **out,
                                                    const uint8_t **inp,
                                                    long len);

// i2d_X509_EXTENSIONS marshals `alg` as a DER-encoded SEQUENCE OF Extension
// (RFC 5280), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_EXTENSIONS(const X509_EXTENSIONS *alg,
                                       uint8_t **outp);

// X509v3_get_ext_count returns the number of extensions in `x`.
OPENSSL_EXPORT int X509v3_get_ext_count(const STACK_OF(X509_EXTENSION) *x);

// X509v3_get_ext_by_NID returns the index of the first extension in `x` with
// type `nid`, or a negative number if not found. If found, callers can use
// `X509v3_get_ext` to look up the extension by index.
//
// If `lastpos` is non-negative, it begins searching at `lastpos` + 1. Callers
// can thus loop over all matching extensions by first passing -1 and then
// passing the previously-returned value until no match is returned.
OPENSSL_EXPORT int X509v3_get_ext_by_NID(const STACK_OF(X509_EXTENSION) *x,
                                         int nid, int lastpos);

// X509v3_get_ext_by_OBJ behaves like `X509v3_get_ext_by_NID` but looks for
// extensions matching `obj`.
OPENSSL_EXPORT int X509v3_get_ext_by_OBJ(const STACK_OF(X509_EXTENSION) *x,
                                         const ASN1_OBJECT *obj, int lastpos);

// X509v3_get_ext_by_critical returns the index of the first extension in `x`
// whose critical bit matches `crit`, or a negative number if no such extension
// was found.
//
// If `lastpos` is non-negative, it begins searching at `lastpos` + 1. Callers
// can thus loop over all matching extensions by first passing -1 and then
// passing the previously-returned value until no match is returned.
OPENSSL_EXPORT int X509v3_get_ext_by_critical(const STACK_OF(X509_EXTENSION) *x,
                                              int crit, int lastpos);

// X509v3_get_ext returns the extension in `x` at index `loc`, or NULL if `loc`
// is out of bounds. This function returns a non-const pointer for OpenSSL
// compatibility, but callers should not mutate the result.
OPENSSL_EXPORT X509_EXTENSION *X509v3_get_ext(const STACK_OF(X509_EXTENSION) *x,
                                              int loc);

// X509v3_delete_ext removes the extension in `x` at index `loc` and returns the
// removed extension, or NULL if `loc` was out of bounds. If an extension was
// returned, the caller must release it with `X509_EXTENSION_free`.
OPENSSL_EXPORT X509_EXTENSION *X509v3_delete_ext(STACK_OF(X509_EXTENSION) *x,
                                                 int loc);

// X509v3_add_ext adds a copy of `ex` to the extension list in `*x`. If `*x` is
// NULL, it allocates a new `STACK_OF(X509_EXTENSION)` to hold the copy and sets
// `*x` to the new list. It returns `*x` on success and NULL on error. The
// caller retains ownership of `ex` and can release it independently of `*x`.
//
// The new extension is inserted at index `loc`, shifting extensions to the
// right. If `loc` is -1 or out of bounds, the new extension is appended to the
// list.
OPENSSL_EXPORT STACK_OF(X509_EXTENSION) *X509v3_add_ext(
    STACK_OF(X509_EXTENSION) **x, const X509_EXTENSION *ex, int loc);


// Built-in extensions.
//
// Several functions in the library encode and decode extension values into a
// C structure to that extension. The following extensions are supported:
//
// - `NID_authority_key_identifier` with type `AUTHORITY_KEYID`
// - `NID_basic_constraints` with type `BASIC_CONSTRAINTS`
// - `NID_certificate_issuer` with type `GENERAL_NAMES`
// - `NID_certificate_policies` with type `CERTIFICATEPOLICIES`
// - `NID_crl_distribution_points` with type `CRL_DIST_POINTS`
// - `NID_crl_number` with type `ASN1_INTEGER`
// - `NID_crl_reason` with type `ASN1_ENUMERATED`
// - `NID_delta_crl` with type `ASN1_INTEGER`
// - `NID_ext_key_usage` with type `EXTENDED_KEY_USAGE`
// - `NID_freshest_crl` with type `ISSUING_DIST_POINT`
// - `NID_id_pkix_OCSP_noCheck` with type `ASN1_NULL`
// - `NID_info_access` with type `AUTHORITY_INFO_ACCESS`
// - `NID_inhibit_any_policy` with type `ASN1_INTEGER`
// - `NID_invalidity_date` with type `ASN1_GENERALIZEDTIME`
// - `NID_issuer_alt_name` with type `GENERAL_NAMES`
// - `NID_issuing_distribution_point` with type `ISSUING_DIST_POINT`
// - `NID_key_usage` with type `ASN1_BIT_STRING`
// - `NID_name_constraints` with type `NAME_CONSTRAINTS`
// - `NID_netscape_base_url` with type `ASN1_IA5STRING`
// - `NID_netscape_ca_policy_url` with type `ASN1_IA5STRING`
// - `NID_netscape_ca_revocation_url` with type `ASN1_IA5STRING`
// - `NID_netscape_cert_type` with type `ASN1_BIT_STRING`
// - `NID_netscape_comment` with type `ASN1_IA5STRING`
// - `NID_netscape_renewal_url` with type `ASN1_IA5STRING`
// - `NID_netscape_revocation_url` with type `ASN1_IA5STRING`
// - `NID_netscape_ssl_server_name` with type `ASN1_IA5STRING`
// - `NID_policy_constraints` with type `POLICY_CONSTRAINTS`
// - `NID_policy_mappings` with type `POLICY_MAPPINGS`
// - `NID_sinfo_access` with type `AUTHORITY_INFO_ACCESS`
// - `NID_subject_alt_name` with type `GENERAL_NAMES`
// - `NID_subject_key_identifier` with type `ASN1_OCTET_STRING`
//
// If an extension does not appear in this list, e.g. for a custom extension,
// callers can instead use functions such as `X509_get_ext_by_OBJ`,
// `X509_EXTENSION_get_data`, and `X509_EXTENSION_create_by_OBJ` to inspect or
// create extensions directly. Although the `X509V3_EXT_METHOD` mechanism allows
// registering custom extensions, doing so is deprecated and may result in
// threading or memory errors.

// X509V3_EXT_d2i decodes `ext` and returns a pointer to a newly-allocated
// structure, with type dependent on the type of the extension. It returns NULL
// if `ext` is an unsupported extension or if there was a syntax error in the
// extension. The caller should cast the return value to the expected type and
// free the structure when done.
//
// WARNING: Casting the return value to the wrong type is a potentially
// exploitable memory error, so callers must not use this function before
// checking `ext` is of a known type. See the list at the top of this section
// for the correct types.
OPENSSL_EXPORT void *X509V3_EXT_d2i(const X509_EXTENSION *ext);

// X509V3_get_d2i finds and decodes the extension in `extensions` of type `nid`.
// If found, it decodes it and returns a newly-allocated structure, with type
// dependent on `nid`. If the extension is not found or on error, it returns
// NULL. The caller may distinguish these cases using the `out_critical` value.
//
// If `out_critical` is not NULL, this function sets `*out_critical` to one if
// the extension is found and critical, zero if it is found and not critical, -1
// if it is not found, and -2 if there is an invalid duplicate extension. Note
// this function may set `*out_critical` to one or zero and still return NULL if
// the extension is found but has a syntax error.
//
// If `out_idx` is not NULL, this function looks for the first occurrence of the
// extension after `*out_idx`. It then sets `*out_idx` to the index of the
// extension, or -1 if not found. If `out_idx` is non-NULL, duplicate extensions
// are not treated as an error. Callers, however, should not rely on this
// behavior as it may be removed in the future. Duplicate extensions are
// forbidden in RFC 5280.
//
// WARNING: This function is difficult to use correctly. Callers should pass a
// non-NULL `out_critical` and check both the return value and `*out_critical`
// to handle errors. If the return value is NULL and `*out_critical` is not -1,
// there was an error. Otherwise, the function succeeded and but may return NULL
// for a missing extension. Callers should pass NULL to `out_idx` so that
// duplicate extensions are handled correctly.
//
// Additionally, casting the return value to the wrong type is a potentially
// exploitable memory error, so callers must ensure the cast and `nid` match.
// See the list at the top of this section for the correct types.
OPENSSL_EXPORT void *X509V3_get_d2i(const STACK_OF(X509_EXTENSION) *extensions,
                                    int nid, int *out_critical, int *out_idx);

// X509V3_EXT_free casts `ext_data` into the type that corresponds to `nid` and
// releases memory associated with it. It returns one on success and zero if
// `nid` is not a known extension.
//
// WARNING: Casting `ext_data` to the wrong type is a potentially exploitable
// memory error, so callers must ensure `ext_data`'s type matches `nid`. See the
// list at the top of this section for the correct types.
//
// TODO(davidben): OpenSSL upstream no longer exposes this function. Remove it?
OPENSSL_EXPORT int X509V3_EXT_free(int nid, void *ext_data);

// X509V3_EXT_i2d casts `ext_struc` into the type that corresponds to
// `ext_nid`, serializes it, and returns a newly-allocated `X509_EXTENSION`
// object containing the serialization, or NULL on error. The `X509_EXTENSION`
// has OID `ext_nid` and is critical if `crit` is one.
//
// WARNING: Casting `ext_struc` to the wrong type is a potentially exploitable
// memory error, so callers must ensure `ext_struct`'s type matches `ext_nid`.
// See the list at the top of this section for the correct types.
OPENSSL_EXPORT X509_EXTENSION *X509V3_EXT_i2d(int ext_nid, int crit,
                                              void *ext_struc);

// The following constants control the behavior of `X509V3_add1_i2d` and related
// functions.

// X509V3_ADD_OP_MASK can be ANDed with the flags to determine how duplicate
// extensions are processed.
#define X509V3_ADD_OP_MASK 0xfL

// X509V3_ADD_DEFAULT causes the function to fail if the extension was already
// present.
#define X509V3_ADD_DEFAULT 0L

// X509V3_ADD_APPEND causes the function to unconditionally appended the new
// extension to the extensions list, even if there is a duplicate.
#define X509V3_ADD_APPEND 1L

// X509V3_ADD_REPLACE causes the function to replace the existing extension, or
// append if it is not present.
#define X509V3_ADD_REPLACE 2L

// X509V3_ADD_REPLACE_EXISTING causes the function to replace the existing
// extension and fail if it is not present.
#define X509V3_ADD_REPLACE_EXISTING 3L

// X509V3_ADD_KEEP_EXISTING causes the function to succeed without replacing the
// extension if already present.
#define X509V3_ADD_KEEP_EXISTING 4L

// X509V3_ADD_DELETE causes the function to remove the matching extension. No
// new extension is added. If there is no matching extension, the function
// fails. The `value` parameter is ignored in this mode.
#define X509V3_ADD_DELETE 5L

// X509V3_ADD_SILENT may be ORed into one of the values above to indicate the
// function should not add to the error queue on duplicate or missing extension.
// The function will continue to return zero in those cases, and it will
// continue to return -1 and add to the error queue on other errors.
#define X509V3_ADD_SILENT 0x10

// X509V3_add1_i2d casts `value` to the type that corresponds to `nid`,
// serializes it, and appends it to the extension list in `*x`. If `*x` is NULL,
// it will set `*x` to a newly-allocated `STACK_OF(X509_EXTENSION)` as needed.
// The `crit` parameter determines whether the new extension is critical.
// `flags` may be some combination of the `X509V3_ADD_*` constants to control
// the function's behavior on duplicate extension.
//
// This function returns one on success, zero if the operation failed due to a
// missing or duplicate extension, and -1 on other errors.
//
// WARNING: Casting `value` to the wrong type is a potentially exploitable
// memory error, so callers must ensure `value`'s type matches `nid`. See the
// list at the top of this section for the correct types.
OPENSSL_EXPORT int X509V3_add1_i2d(STACK_OF(X509_EXTENSION) **x, int nid,
                                   void *value, int crit, unsigned long flags);


// Basic constraints.
//
// The basic constraints extension (RFC 5280, section 4.2.1.9) determines
// whether a certificate is a CA certificate and, if so, optionally constrains
// the maximum depth of the certificate chain.

// A BASIC_CONSTRAINTS_st, aka `BASIC_CONSTRAINTS` represents an
// BasicConstraints structure (RFC 5280).
struct BASIC_CONSTRAINTS_st {
  ASN1_BOOLEAN ca;
  ASN1_INTEGER *pathlen;
} /* BASIC_CONSTRAINTS */;

// BASIC_CONSTRAINTS is an `ASN1_ITEM` whose ASN.1 type is BasicConstraints (RFC
// 5280) and C type is `BASIC_CONSTRAINTS*`.
DECLARE_ASN1_ITEM(BASIC_CONSTRAINTS)

// BASIC_CONSTRAINTS_new returns a newly-allocated, empty `BASIC_CONSTRAINTS`
// object, or NULL on error.
OPENSSL_EXPORT BASIC_CONSTRAINTS *BASIC_CONSTRAINTS_new(void);

// BASIC_CONSTRAINTS_free releases memory associated with `bcons`.
OPENSSL_EXPORT void BASIC_CONSTRAINTS_free(BASIC_CONSTRAINTS *bcons);

// d2i_BASIC_CONSTRAINTS parses up to `len` bytes from `*inp` as a DER-encoded
// BasicConstraints (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT BASIC_CONSTRAINTS *d2i_BASIC_CONSTRAINTS(BASIC_CONSTRAINTS **out,
                                                        const uint8_t **inp,
                                                        long len);

// i2d_BASIC_CONSTRAINTS marshals `bcons` as a DER-encoded BasicConstraints (RFC
// 5280), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_BASIC_CONSTRAINTS(const BASIC_CONSTRAINTS *bcons,
                                         uint8_t **outp);


// Extended key usage.
//
// The extended key usage extension (RFC 5280, section 4.2.1.12) indicates the
// purposes of the certificate's public key. Such constraints are important to
// avoid cross-protocol attacks.

typedef STACK_OF(ASN1_OBJECT) EXTENDED_KEY_USAGE;

// EXTENDED_KEY_USAGE is an `ASN1_ITEM` whose ASN.1 type is ExtKeyUsageSyntax
// (RFC 5280) and C type is `STACK_OF(ASN1_OBJECT)*`, or `EXTENDED_KEY_USAGE*`.
DECLARE_ASN1_ITEM(EXTENDED_KEY_USAGE)

// EXTENDED_KEY_USAGE_new returns a newly-allocated, empty `EXTENDED_KEY_USAGE`
// object, or NULL on error.
OPENSSL_EXPORT EXTENDED_KEY_USAGE *EXTENDED_KEY_USAGE_new(void);

// EXTENDED_KEY_USAGE_free releases memory associated with `eku`.
OPENSSL_EXPORT void EXTENDED_KEY_USAGE_free(EXTENDED_KEY_USAGE *eku);

// d2i_EXTENDED_KEY_USAGE parses up to `len` bytes from `*inp` as a DER-encoded
// ExtKeyUsageSyntax (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT EXTENDED_KEY_USAGE *d2i_EXTENDED_KEY_USAGE(
    EXTENDED_KEY_USAGE **out, const uint8_t **inp, long len);

// i2d_EXTENDED_KEY_USAGE marshals `eku` as a DER-encoded ExtKeyUsageSyntax (RFC
// 5280), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_EXTENDED_KEY_USAGE(const EXTENDED_KEY_USAGE *eku,
                                          uint8_t **outp);


// General names.
//
// A `GENERAL_NAME` represents an X.509 GeneralName structure, defined in RFC
// 5280, Section 4.2.1.6. General names are distinct from names (`X509_NAME`). A
// general name is a CHOICE type which may contain one of several name types,
// most commonly a DNS name or an IP address. General names most commonly appear
// in the subject alternative name (SAN) extension, though they are also used in
// other extensions.
//
// Many extensions contain a SEQUENCE OF GeneralName, or GeneralNames, so
// `STACK_OF(GENERAL_NAME)` is defined and aliased to `GENERAL_NAMES`.

typedef struct otherName_st {
  ASN1_OBJECT *type_id;
  ASN1_TYPE *value;
} OTHERNAME;

typedef struct EDIPartyName_st {
  ASN1_STRING *nameAssigner;
  ASN1_STRING *partyName;
} EDIPARTYNAME;

// GEN_* are constants for the `type` field of `GENERAL_NAME`, defined below.
#define GEN_OTHERNAME 0
#define GEN_EMAIL 1
#define GEN_DNS 2
#define GEN_X400 3
#define GEN_DIRNAME 4
#define GEN_EDIPARTY 5
#define GEN_URI 6
#define GEN_IPADD 7
#define GEN_RID 8

// A GENERAL_NAME_st, aka `GENERAL_NAME`, represents an X.509 GeneralName. The
// `type` field determines which member of `d` is active. A `GENERAL_NAME` may
// also be empty, in which case `type` is -1 and `d` is NULL. Empty
// `GENERAL_NAME`s are invalid and will never be returned from the parser, but
// may be created temporarily, e.g. by `GENERAL_NAME_new`.
//
// WARNING: `type` and `d` must be kept consistent. An inconsistency will result
// in a potentially exploitable memory error.
struct GENERAL_NAME_st {
  int type;
  union {
    char *ptr;
    OTHERNAME *otherName;
    ASN1_IA5STRING *rfc822Name;
    ASN1_IA5STRING *dNSName;
    ASN1_STRING *x400Address;
    X509_NAME *directoryName;
    EDIPARTYNAME *ediPartyName;
    ASN1_IA5STRING *uniformResourceIdentifier;
    ASN1_OCTET_STRING *iPAddress;
    ASN1_OBJECT *registeredID;

    // Old names
    ASN1_OCTET_STRING *ip;  // iPAddress
    X509_NAME *dirn;        // dirn
    ASN1_IA5STRING *ia5;    // rfc822Name, dNSName, uniformResourceIdentifier
    ASN1_OBJECT *rid;       // registeredID
  } d;
} /* GENERAL_NAME */;

// GENERAL_NAME_new returns a new, empty `GENERAL_NAME`, or NULL on error.
OPENSSL_EXPORT GENERAL_NAME *GENERAL_NAME_new(void);

// GENERAL_NAME_free releases memory associated with `gen`.
OPENSSL_EXPORT void GENERAL_NAME_free(GENERAL_NAME *gen);

// d2i_GENERAL_NAME parses up to `len` bytes from `*inp` as a DER-encoded X.509
// GeneralName (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT GENERAL_NAME *d2i_GENERAL_NAME(GENERAL_NAME **out,
                                              const uint8_t **inp, long len);

// i2d_GENERAL_NAME marshals `in` as a DER-encoded X.509 GeneralName (RFC 5280),
// as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_GENERAL_NAME(const GENERAL_NAME *in, uint8_t **outp);

// GENERAL_NAME_dup returns a newly-allocated copy of `gen`, or NULL on error.
// This function works by serializing the structure, so it will fail if `gen` is
// empty.
OPENSSL_EXPORT GENERAL_NAME *GENERAL_NAME_dup(const GENERAL_NAME *gen);

// GENERAL_NAMES_new returns a new, empty `GENERAL_NAMES`, or NULL on error.
OPENSSL_EXPORT GENERAL_NAMES *GENERAL_NAMES_new(void);

// GENERAL_NAMES_free releases memory associated with `gens`.
OPENSSL_EXPORT void GENERAL_NAMES_free(GENERAL_NAMES *gens);

// d2i_GENERAL_NAMES parses up to `len` bytes from `*inp` as a DER-encoded
// SEQUENCE OF GeneralName, as described in `d2i_SAMPLE`.
OPENSSL_EXPORT GENERAL_NAMES *d2i_GENERAL_NAMES(GENERAL_NAMES **out,
                                                const uint8_t **inp, long len);

// i2d_GENERAL_NAMES marshals `in` as a DER-encoded SEQUENCE OF GeneralName, as
// described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_GENERAL_NAMES(const GENERAL_NAMES *in, uint8_t **outp);

// OTHERNAME_new returns a new, empty `OTHERNAME`, or NULL on error.
OPENSSL_EXPORT OTHERNAME *OTHERNAME_new(void);

// OTHERNAME_free releases memory associated with `name`.
OPENSSL_EXPORT void OTHERNAME_free(OTHERNAME *name);

// EDIPARTYNAME_new returns a new, empty `EDIPARTYNAME`, or NULL on error.
// EDIPartyName is rarely used in practice, so callers are unlikely to need this
// function.
OPENSSL_EXPORT EDIPARTYNAME *EDIPARTYNAME_new(void);

// EDIPARTYNAME_free releases memory associated with `name`. EDIPartyName is
// rarely used in practice, so callers are unlikely to need this function.
OPENSSL_EXPORT void EDIPARTYNAME_free(EDIPARTYNAME *name);

// GENERAL_NAME_set0_value set `gen`'s type and value to `type` and `value`.
// `type` must be a `GEN_*` constant and `value` must be an object of the
// corresponding type. `gen` takes ownership of `value`, so `value` must have
// been an allocated object.
//
// WARNING: `gen` must be empty (typically as returned from `GENERAL_NAME_new`)
// before calling this function. If `gen` already contained a value, the
// previous contents will be leaked.
OPENSSL_EXPORT void GENERAL_NAME_set0_value(GENERAL_NAME *gen, int type,
                                            void *value);

// GENERAL_NAME_get0_value returns the in-memory representation of `gen`'s
// contents and, `out_type` is not NULL, sets `*out_type` to the type of `gen`,
// which will be a `GEN_*` constant. If `gen` is incomplete, the return value
// will be NULL and the type will be -1.
//
// WARNING: Casting the result of this function to the wrong type is a
// potentially exploitable memory error. Callers must check `gen`'s type, either
// via `*out_type` or checking `gen->type` directly, before inspecting the
// result.
//
// WARNING: This function is not const-correct. The return value should be
// const. Callers should not mutate the returned object.
OPENSSL_EXPORT void *GENERAL_NAME_get0_value(const GENERAL_NAME *gen,
                                             int *out_type);

// GENERAL_NAME_set0_othername sets `gen` to be an OtherName with type `oid` and
// value `value`. On success, it returns one and takes ownership of `oid` and
// `value`, which must be created in a way compatible with `ASN1_OBJECT_free`
// and `ASN1_TYPE_free`, respectively. On allocation failure, it returns zero.
// In the failure case, the caller retains ownership of `oid` and `value` and
// must release them when done.
//
// WARNING: `gen` must be empty (typically as returned from `GENERAL_NAME_new`)
// before calling this function. If `gen` already contained a value, the
// previously contents will be leaked.
OPENSSL_EXPORT int GENERAL_NAME_set0_othername(GENERAL_NAME *gen,
                                               ASN1_OBJECT *oid,
                                               ASN1_TYPE *value);

// GENERAL_NAME_get0_otherName, if `gen` is an OtherName, sets `*out_oid` and
// `*out_value` to the OtherName's type-id and value, respectively, and returns
// one. If `gen` is not an OtherName, it returns zero and leaves `*out_oid` and
// `*out_value` unmodified. Either of `out_oid` or `out_value` may be NULL to
// ignore the value.
//
// WARNING: This function is not const-correct. `out_oid` and `out_value` are
// not const, but callers should not mutate the resulting objects.
OPENSSL_EXPORT int GENERAL_NAME_get0_otherName(const GENERAL_NAME *gen,
                                               ASN1_OBJECT **out_oid,
                                               ASN1_TYPE **out_value);


// Authority key identifier.
//
// The authority key identifier extension (RFC 5280, section 4.2.1.1) allows a
// certificate to more precisely identify its issuer. This is helpful when
// multiple certificates share a name. Only the keyIdentifier (`keyid` in
// `AUTHORITY_KEYID`) field is used in practice.

// A AUTHORITY_KEYID_st, aka `AUTHORITY_KEYID`, represents an
// AuthorityKeyIdentifier structure (RFC 5280).
struct AUTHORITY_KEYID_st {
  ASN1_OCTET_STRING *keyid;
  GENERAL_NAMES *issuer;
  ASN1_INTEGER *serial;
} /* AUTHORITY_KEYID */;

// AUTHORITY_KEYID is an `ASN1_ITEM` whose ASN.1 type is AuthorityKeyIdentifier
// (RFC 5280) and C type is `AUTHORITY_KEYID*`.
DECLARE_ASN1_ITEM(AUTHORITY_KEYID)

// AUTHORITY_KEYID_new returns a newly-allocated, empty `AUTHORITY_KEYID`
// object, or NULL on error.
OPENSSL_EXPORT AUTHORITY_KEYID *AUTHORITY_KEYID_new(void);

// AUTHORITY_KEYID_free releases memory associated with `akid`.
OPENSSL_EXPORT void AUTHORITY_KEYID_free(AUTHORITY_KEYID *akid);

// d2i_AUTHORITY_KEYID parses up to `len` bytes from `*inp` as a DER-encoded
// AuthorityKeyIdentifier (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT AUTHORITY_KEYID *d2i_AUTHORITY_KEYID(AUTHORITY_KEYID **out,
                                                    const uint8_t **inp,
                                                    long len);

// i2d_AUTHORITY_KEYID marshals `akid` as a DER-encoded AuthorityKeyIdentifier
// (RFC 5280), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_AUTHORITY_KEYID(const AUTHORITY_KEYID *akid,
                                       uint8_t **outp);


// Name constraints.
//
// The name constraints extension (RFC 5280, section 4.2.1.10) constrains which
// names may be asserted by certificates issued by some CA. For example, a
// general CA may issue an intermediate certificate to the owner of example.com,
// but constrained to ".example.com".

// A GENERAL_SUBTREE represents a GeneralSubtree structure (RFC 5280).
typedef struct GENERAL_SUBTREE_st {
  GENERAL_NAME *base;
  ASN1_INTEGER *minimum;
  ASN1_INTEGER *maximum;
} GENERAL_SUBTREE;

DEFINE_STACK_OF(GENERAL_SUBTREE)

// GENERAL_SUBTREE_new returns a newly-allocated, empty `GENERAL_SUBTREE`
// object, or NULL on error.
OPENSSL_EXPORT GENERAL_SUBTREE *GENERAL_SUBTREE_new(void);

// GENERAL_SUBTREE_free releases memory associated with `subtree`.
OPENSSL_EXPORT void GENERAL_SUBTREE_free(GENERAL_SUBTREE *subtree);

// A NAME_CONSTRAINTS_st, aka `NAME_CONSTRAINTS`, represents a NameConstraints
// structure (RFC 5280).
struct NAME_CONSTRAINTS_st {
  STACK_OF(GENERAL_SUBTREE) *permittedSubtrees;
  STACK_OF(GENERAL_SUBTREE) *excludedSubtrees;
} /* NAME_CONSTRAINTS */;

// NAME_CONSTRAINTS is an `ASN1_ITEM` whose ASN.1 type is NameConstraints (RFC
// 5280) and C type is `NAME_CONSTRAINTS*`.
DECLARE_ASN1_ITEM(NAME_CONSTRAINTS)

// NAME_CONSTRAINTS_new returns a newly-allocated, empty `NAME_CONSTRAINTS`
// object, or NULL on error.
OPENSSL_EXPORT NAME_CONSTRAINTS *NAME_CONSTRAINTS_new(void);

// NAME_CONSTRAINTS_free releases memory associated with `ncons`.
OPENSSL_EXPORT void NAME_CONSTRAINTS_free(NAME_CONSTRAINTS *ncons);


// Authority information access.
//
// The authority information access extension (RFC 5280, 4.2.2.1) describes
// where to obtain information about the issuer of a certificate. It is most
// commonly used with accessMethod values of id-ad-caIssuers and id-ad-ocsp, to
// indicate where to fetch the issuer certificate (if not provided in-band) and
// the issuer's OCSP responder, respectively.

// An ACCESS_DESCRIPTION represents an AccessDescription structure (RFC 5280).
typedef struct ACCESS_DESCRIPTION_st {
  ASN1_OBJECT *method;
  GENERAL_NAME *location;
} ACCESS_DESCRIPTION;

DEFINE_STACK_OF(ACCESS_DESCRIPTION)

// ACCESS_DESCRIPTION_new returns a newly-allocated, empty `ACCESS_DESCRIPTION`
// object, or NULL on error.
OPENSSL_EXPORT ACCESS_DESCRIPTION *ACCESS_DESCRIPTION_new(void);

// ACCESS_DESCRIPTION_free releases memory associated with `desc`.
OPENSSL_EXPORT void ACCESS_DESCRIPTION_free(ACCESS_DESCRIPTION *desc);

typedef STACK_OF(ACCESS_DESCRIPTION) AUTHORITY_INFO_ACCESS;

// AUTHORITY_INFO_ACCESS is an `ASN1_ITEM` whose ASN.1 type is
// AuthorityInfoAccessSyntax (RFC 5280) and C type is
// `STACK_OF(ACCESS_DESCRIPTION)*`, or `AUTHORITY_INFO_ACCESS*`.
DECLARE_ASN1_ITEM(AUTHORITY_INFO_ACCESS)

// AUTHORITY_INFO_ACCESS_new returns a newly-allocated, empty
// `AUTHORITY_INFO_ACCESS` object, or NULL on error.
OPENSSL_EXPORT AUTHORITY_INFO_ACCESS *AUTHORITY_INFO_ACCESS_new(void);

// AUTHORITY_INFO_ACCESS_free releases memory associated with `aia`.
OPENSSL_EXPORT void AUTHORITY_INFO_ACCESS_free(AUTHORITY_INFO_ACCESS *aia);

// d2i_AUTHORITY_INFO_ACCESS parses up to `len` bytes from `*inp` as a
// DER-encoded AuthorityInfoAccessSyntax (RFC 5280), as described in
// `d2i_SAMPLE`.
OPENSSL_EXPORT AUTHORITY_INFO_ACCESS *d2i_AUTHORITY_INFO_ACCESS(
    AUTHORITY_INFO_ACCESS **out, const uint8_t **inp, long len);

// i2d_AUTHORITY_INFO_ACCESS marshals `aia` as a DER-encoded
// AuthorityInfoAccessSyntax (RFC 5280), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_AUTHORITY_INFO_ACCESS(const AUTHORITY_INFO_ACCESS *aia,
                                             uint8_t **outp);


// CRL distribution points.
//
// The CRL distribution points extension (RFC 5280, 4.2.1.13) indicates where to
// fetch a certificate issuer's CRL. The corresponding issuing distribution
// point CRL extension (RFC 5280, section 5.2.5) matches against this extension.

// A DIST_POINT_NAME represents a DistributionPointName structure (RFC 5280).
// The `name` field contains the CHOICE value and is determined by `type`. If
// `type` is zero, `name` must be a `fullname`. If `type` is one, `name` must be
// a `relativename`.
//
// WARNING: `type` and `name` must be kept consistent. An inconsistency will
// result in a potentially exploitable memory error.
typedef struct DIST_POINT_NAME_st {
  int type;
  union {
    GENERAL_NAMES *fullname;
    STACK_OF(X509_NAME_ENTRY) *relativename;
  } name;
  // If relativename then this contains the full distribution point name
  X509_NAME *dpname;
} DIST_POINT_NAME;

// DIST_POINT_NAME_new returns a newly-allocated, empty `DIST_POINT_NAME`
// object, or NULL on error.
OPENSSL_EXPORT DIST_POINT_NAME *DIST_POINT_NAME_new(void);

// DIST_POINT_NAME_free releases memory associated with `name`.
OPENSSL_EXPORT void DIST_POINT_NAME_free(DIST_POINT_NAME *name);

// A DIST_POINT_st, aka `DIST_POINT`, represents a DistributionPoint structure
// (RFC 5280).
struct DIST_POINT_st {
  DIST_POINT_NAME *distpoint;
  ASN1_BIT_STRING *reasons;
  GENERAL_NAMES *CRLissuer;
} /* DIST_POINT */;

DEFINE_STACK_OF(DIST_POINT)

// DIST_POINT_new returns a newly-allocated, empty `DIST_POINT` object, or NULL
// on error.
OPENSSL_EXPORT DIST_POINT *DIST_POINT_new(void);

// DIST_POINT_free releases memory associated with `dp`.
OPENSSL_EXPORT void DIST_POINT_free(DIST_POINT *dp);

typedef STACK_OF(DIST_POINT) CRL_DIST_POINTS;

// CRL_DIST_POINTS is an `ASN1_ITEM` whose ASN.1 type is CRLDistributionPoints
// (RFC 5280) and C type is `CRL_DIST_POINTS*`.
DECLARE_ASN1_ITEM(CRL_DIST_POINTS)

// CRL_DIST_POINTS_new returns a newly-allocated, empty `CRL_DIST_POINTS`
// object, or NULL on error.
OPENSSL_EXPORT CRL_DIST_POINTS *CRL_DIST_POINTS_new(void);

// CRL_DIST_POINTS_free releases memory associated with `crldp`.
OPENSSL_EXPORT void CRL_DIST_POINTS_free(CRL_DIST_POINTS *crldp);

// d2i_CRL_DIST_POINTS parses up to `len` bytes from `*inp` as a DER-encoded
// CRLDistributionPoints (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT CRL_DIST_POINTS *d2i_CRL_DIST_POINTS(CRL_DIST_POINTS **out,
                                                    const uint8_t **inp,
                                                    long len);

// i2d_CRL_DIST_POINTS marshals `crldp` as a DER-encoded CRLDistributionPoints
// (RFC 5280), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_CRL_DIST_POINTS(const CRL_DIST_POINTS *crldp,
                                       uint8_t **outp);

// A ISSUING_DIST_POINT_st, aka `ISSUING_DIST_POINT`, represents a
// IssuingDistributionPoint structure (RFC 5280).
struct ISSUING_DIST_POINT_st {
  DIST_POINT_NAME *distpoint;
  ASN1_BOOLEAN onlyuser;
  ASN1_BOOLEAN onlyCA;
  ASN1_BIT_STRING *onlysomereasons;
  ASN1_BOOLEAN indirectCRL;
  ASN1_BOOLEAN onlyattr;
} /* ISSUING_DIST_POINT */;

// ISSUING_DIST_POINT is an `ASN1_ITEM` whose ASN.1 type is
// IssuingDistributionPoint (RFC 5280) and C type is `ISSUING_DIST_POINT*`.
DECLARE_ASN1_ITEM(ISSUING_DIST_POINT)

// ISSUING_DIST_POINT_new returns a newly-allocated, empty `ISSUING_DIST_POINT`
// object, or NULL on error.
OPENSSL_EXPORT ISSUING_DIST_POINT *ISSUING_DIST_POINT_new(void);

// ISSUING_DIST_POINT_free releases memory associated with `idp`.
OPENSSL_EXPORT void ISSUING_DIST_POINT_free(ISSUING_DIST_POINT *idp);

// d2i_ISSUING_DIST_POINT parses up to `len` bytes from `*inp` as a DER-encoded
// IssuingDistributionPoint (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT ISSUING_DIST_POINT *d2i_ISSUING_DIST_POINT(
    ISSUING_DIST_POINT **out, const uint8_t **inp, long len);

// i2d_ISSUING_DIST_POINT marshals `idp` as a DER-encoded
// IssuingDistributionPoint (RFC 5280), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_ISSUING_DIST_POINT(const ISSUING_DIST_POINT *idp,
                                          uint8_t **outp);


// Certificate policies.
//
// The certificate policies extension (RFC 5280, section 4.2.1.4), along with a
// suite of related extensions determines the "policies" that apply to a
// certificate path. Evaluating these policies is extremely complex and has led
// to denial-of-service vulnerabilities in several X.509 implementations. See
// RFC 9618.
//
// Do not use this mechanism.

// A NOTICEREF represents a NoticeReference structure (RFC 5280).
typedef struct NOTICEREF_st {
  ASN1_STRING *organization;
  STACK_OF(ASN1_INTEGER) *noticenos;
} NOTICEREF;

// NOTICEREF_new returns a newly-allocated, empty `NOTICEREF` object, or NULL
// on error.
OPENSSL_EXPORT NOTICEREF *NOTICEREF_new(void);

// NOTICEREF_free releases memory associated with `ref`.
OPENSSL_EXPORT void NOTICEREF_free(NOTICEREF *ref);

// A USERNOTICE represents a UserNotice structure (RFC 5280).
typedef struct USERNOTICE_st {
  NOTICEREF *noticeref;
  ASN1_STRING *exptext;
} USERNOTICE;

// USERNOTICE_new returns a newly-allocated, empty `USERNOTICE` object, or NULL
// on error.
OPENSSL_EXPORT USERNOTICE *USERNOTICE_new(void);

// USERNOTICE_free releases memory associated with `notice`.
OPENSSL_EXPORT void USERNOTICE_free(USERNOTICE *notice);

// A POLICYQUALINFO represents a PolicyQualifierInfo structure (RFC 5280). `d`
// contains the qualifier field of the PolicyQualifierInfo. Its type is
// determined by `pqualid`. If `pqualid` is `NID_id_qt_cps`, `d` must be
// `cpsuri`. If `pqualid` is `NID_id_qt_unotice`, `d` must be `usernotice`.
// Otherwise, `d` must be `other`.
//
// WARNING: `pqualid` and `d` must be kept consistent. An inconsistency will
// result in a potentially exploitable memory error.
typedef struct POLICYQUALINFO_st {
  ASN1_OBJECT *pqualid;
  union {
    ASN1_IA5STRING *cpsuri;
    USERNOTICE *usernotice;
    ASN1_TYPE *other;
  } d;
} POLICYQUALINFO;

DEFINE_STACK_OF(POLICYQUALINFO)

// POLICYQUALINFO_new returns a newly-allocated, empty `POLICYQUALINFO` object,
// or NULL on error.
OPENSSL_EXPORT POLICYQUALINFO *POLICYQUALINFO_new(void);

// POLICYQUALINFO_free releases memory associated with `info`.
OPENSSL_EXPORT void POLICYQUALINFO_free(POLICYQUALINFO *info);

// A POLICYINFO represents a PolicyInformation structure (RFC 5280).
typedef struct POLICYINFO_st {
  ASN1_OBJECT *policyid;
  STACK_OF(POLICYQUALINFO) *qualifiers;
} POLICYINFO;

DEFINE_STACK_OF(POLICYINFO)

// POLICYINFO_new returns a newly-allocated, empty `POLICYINFO` object, or NULL
// on error.
OPENSSL_EXPORT POLICYINFO *POLICYINFO_new(void);

// POLICYINFO_free releases memory associated with `info`.
OPENSSL_EXPORT void POLICYINFO_free(POLICYINFO *info);

typedef STACK_OF(POLICYINFO) CERTIFICATEPOLICIES;

// CERTIFICATEPOLICIES is an `ASN1_ITEM` whose ASN.1 type is CertificatePolicies
// (RFC 5280) and C type is `STACK_OF(POLICYINFO)*`, or `CERTIFICATEPOLICIES*`.
DECLARE_ASN1_ITEM(CERTIFICATEPOLICIES)

// CERTIFICATEPOLICIES_new returns a newly-allocated, empty
// `CERTIFICATEPOLICIES` object, or NULL on error.
OPENSSL_EXPORT CERTIFICATEPOLICIES *CERTIFICATEPOLICIES_new(void);

// CERTIFICATEPOLICIES_free releases memory associated with `policies`.
OPENSSL_EXPORT void CERTIFICATEPOLICIES_free(CERTIFICATEPOLICIES *policies);

// d2i_CERTIFICATEPOLICIES parses up to `len` bytes from `*inp` as a DER-encoded
// CertificatePolicies (RFC 5280), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT CERTIFICATEPOLICIES *d2i_CERTIFICATEPOLICIES(
    CERTIFICATEPOLICIES **out, const uint8_t **inp, long len);

// i2d_CERTIFICATEPOLICIES marshals `policies` as a DER-encoded
// CertificatePolicies (RFC 5280), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_CERTIFICATEPOLICIES(const CERTIFICATEPOLICIES *policies,
                                           uint8_t **outp);

// A POLICY_MAPPING represents an individual element of a PolicyMappings
// structure (RFC 5280).
typedef struct POLICY_MAPPING_st {
  ASN1_OBJECT *issuerDomainPolicy;
  ASN1_OBJECT *subjectDomainPolicy;
} POLICY_MAPPING;

DEFINE_STACK_OF(POLICY_MAPPING)

// POLICY_MAPPING_new returns a newly-allocated, empty `POLICY_MAPPING` object,
// or NULL on error.
OPENSSL_EXPORT POLICY_MAPPING *POLICY_MAPPING_new(void);

// POLICY_MAPPING_free releases memory associated with `mapping`.
OPENSSL_EXPORT void POLICY_MAPPING_free(POLICY_MAPPING *mapping);

typedef STACK_OF(POLICY_MAPPING) POLICY_MAPPINGS;

// POLICY_MAPPINGS is an `ASN1_ITEM` whose ASN.1 type is PolicyMappings (RFC
// 5280) and C type is `STACK_OF(POLICY_MAPPING)*`, or `POLICY_MAPPINGS*`.
DECLARE_ASN1_ITEM(POLICY_MAPPINGS)

// A POLICY_CONSTRAINTS represents a PolicyConstraints structure (RFC 5280).
typedef struct POLICY_CONSTRAINTS_st {
  ASN1_INTEGER *requireExplicitPolicy;
  ASN1_INTEGER *inhibitPolicyMapping;
} POLICY_CONSTRAINTS;

// POLICY_CONSTRAINTS is an `ASN1_ITEM` whose ASN.1 type is PolicyConstraints
// (RFC 5280) and C type is `POLICY_CONSTRAINTS*`.
DECLARE_ASN1_ITEM(POLICY_CONSTRAINTS)

// POLICY_CONSTRAINTS_new returns a newly-allocated, empty `POLICY_CONSTRAINTS`
// object, or NULL on error.
OPENSSL_EXPORT POLICY_CONSTRAINTS *POLICY_CONSTRAINTS_new(void);

// POLICY_CONSTRAINTS_free releases memory associated with `pcons`.
OPENSSL_EXPORT void POLICY_CONSTRAINTS_free(POLICY_CONSTRAINTS *pcons);


// Algorithm identifiers.
//
// An `X509_ALGOR` represents an AlgorithmIdentifier structure, used in X.509
// to represent signature algorithms and public key algorithms.

DEFINE_STACK_OF(X509_ALGOR)

// X509_ALGOR is an `ASN1_ITEM` whose ASN.1 type is AlgorithmIdentifier and C
// type is `X509_ALGOR*`.
DECLARE_ASN1_ITEM(X509_ALGOR)

// X509_ALGOR_new returns a newly-allocated, empty `X509_ALGOR` object, or NULL
// on error.
OPENSSL_EXPORT X509_ALGOR *X509_ALGOR_new(void);

// X509_ALGOR_dup returns a newly-allocated copy of `alg`, or NULL on error.
// This function works by serializing the structure, so if `alg` is incomplete,
// it may fail.
OPENSSL_EXPORT X509_ALGOR *X509_ALGOR_dup(const X509_ALGOR *alg);

// X509_ALGOR_copy sets `dst` to a copy of the contents of `src`. It returns one
// on success and zero on error.
OPENSSL_EXPORT int X509_ALGOR_copy(X509_ALGOR *dst, const X509_ALGOR *src);

// X509_ALGOR_free releases memory associated with `alg`.
OPENSSL_EXPORT void X509_ALGOR_free(X509_ALGOR *alg);

// d2i_X509_ALGOR parses up to `len` bytes from `*inp` as a DER-encoded
// AlgorithmIdentifier, as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_ALGOR *d2i_X509_ALGOR(X509_ALGOR **out, const uint8_t **inp,
                                          long len);

// i2d_X509_ALGOR marshals `alg` as a DER-encoded AlgorithmIdentifier, as
// described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_ALGOR(const X509_ALGOR *alg, uint8_t **outp);

// X509_ALGOR_set0 sets `alg` to an AlgorithmIdentifier with algorithm `obj` and
// parameter determined by `param_type` and `param_value`. It returns one on
// success and zero on error. This function takes ownership of `obj` and
// `param_value` on success.
//
// If `param_type` is `V_ASN1_UNDEF`, the parameter is omitted. If `param_type`
// is zero, the parameter is left unchanged. Otherwise, `param_type` and
// `param_value` are interpreted as in `ASN1_TYPE_set`.
//
// Note omitting the parameter (`V_ASN1_UNDEF`) and encoding an explicit NULL
// value (`V_ASN1_NULL`) are different. Some algorithms require one and some the
// other. Consult the relevant specification before calling this function. The
// correct parameter for an RSASSA-PKCS1-v1_5 signature is `V_ASN1_NULL`. The
// correct one for an ECDSA or Ed25519 signature is `V_ASN1_UNDEF`.
OPENSSL_EXPORT int X509_ALGOR_set0(X509_ALGOR *alg, ASN1_OBJECT *obj,
                                   int param_type, void *param_value);

// X509_ALGOR_get0 sets `*out_obj` to the `alg`'s algorithm. If `alg`'s
// parameter is omitted, it sets `*out_param_type` and `*out_param_value` to
// `V_ASN1_UNDEF` and NULL. Otherwise, it sets `*out_param_type` and
// `*out_param_value` to the parameter, using the same representation as
// `ASN1_TYPE_set0`. See `ASN1_TYPE_set0` and `ASN1_TYPE` for details.
//
// Callers that require the parameter in serialized form should, after checking
// for `V_ASN1_UNDEF`, use `ASN1_TYPE_set1` and `d2i_ASN1_TYPE`, rather than
// inspecting `*out_param_value`.
//
// Each of `out_obj`, `out_param_type`, and `out_param_value` may be NULL to
// ignore the output. If `out_param_type` is NULL, `out_param_value` is ignored.
//
// WARNING: If `*out_param_type` is set to `V_ASN1_UNDEF`, OpenSSL and older
// revisions of BoringSSL leave `*out_param_value` unset rather than setting it
// to NULL. Callers that support both OpenSSL and BoringSSL should not assume
// `*out_param_value` is uniformly initialized.
OPENSSL_EXPORT void X509_ALGOR_get0(const ASN1_OBJECT **out_obj,
                                    int *out_param_type,
                                    const void **out_param_value,
                                    const X509_ALGOR *alg);

// X509_ALGOR_set_md sets `alg` to the hash function `md`. Note this
// AlgorithmIdentifier represents the hash function itself, not a signature
// algorithm that uses `md`. It returns one on success and zero on error.
//
// Due to historical specification mistakes (see Section 2.1 of RFC 4055), the
// parameters field is sometimes omitted and sometimes a NULL value. When used
// in RSASSA-PSS and RSAES-OAEP, it should be a NULL value. In other contexts,
// the parameters should be omitted. This function assumes the caller is
// constructing a RSASSA-PSS or RSAES-OAEP AlgorithmIdentifier and includes a
// NULL parameter. This differs from OpenSSL's behavior.
//
// TODO(davidben): Rename this function, or perhaps just add a bespoke API for
// constructing PSS and move on.
OPENSSL_EXPORT int X509_ALGOR_set_md(X509_ALGOR *alg, const EVP_MD *md);

// X509_ALGOR_cmp returns zero if `a` and `b` are equal, and some non-zero value
// otherwise. Note this function can only be used for equality checks, not an
// ordering.
OPENSSL_EXPORT int X509_ALGOR_cmp(const X509_ALGOR *a, const X509_ALGOR *b);


// Attributes.
//
// Unlike certificates and CRLs, CSRs use a separate Attribute structure (RFC
// 2985, RFC 2986) for extensibility. This is represented by the library as
// `X509_ATTRIBUTE`.

DEFINE_STACK_OF(X509_ATTRIBUTE)

// X509_ATTRIBUTE_new returns a newly-allocated, empty `X509_ATTRIBUTE` object,
// or NULL on error. `X509_ATTRIBUTE_set1_*` may be used to finish initializing
// it.
OPENSSL_EXPORT X509_ATTRIBUTE *X509_ATTRIBUTE_new(void);

// X509_ATTRIBUTE_dup returns a newly-allocated copy of `attr`, or NULL on
// error. This function works by serializing the structure, so if `attr` is
// incomplete, it may fail.
OPENSSL_EXPORT X509_ATTRIBUTE *X509_ATTRIBUTE_dup(const X509_ATTRIBUTE *attr);

// X509_ATTRIBUTE_free releases memory associated with `attr`.
OPENSSL_EXPORT void X509_ATTRIBUTE_free(X509_ATTRIBUTE *attr);

// d2i_X509_ATTRIBUTE parses up to `len` bytes from `*inp` as a DER-encoded
// Attribute (RFC 2986), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_ATTRIBUTE *d2i_X509_ATTRIBUTE(X509_ATTRIBUTE **out,
                                                  const uint8_t **inp,
                                                  long len);

// i2d_X509_ATTRIBUTE marshals `alg` as a DER-encoded Attribute (RFC 2986), as
// described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_ATTRIBUTE(const X509_ATTRIBUTE *alg,
                                      uint8_t **outp);

// X509_ATTRIBUTE_create returns a newly-allocated `X509_ATTRIBUTE`, or NULL on
// error. The attribute has type `nid` and contains a single value determined by
// `attrtype` and `value`, which are interpreted as in `ASN1_TYPE_set`. Note
// this function takes ownership of `value`.
OPENSSL_EXPORT X509_ATTRIBUTE *X509_ATTRIBUTE_create(int nid, int attrtype,
                                                     void *value);

// X509_ATTRIBUTE_create_by_NID returns a newly-allocated `X509_ATTRIBUTE` of
// type `nid`, or NULL on error. The value is determined as in
// `X509_ATTRIBUTE_set1_data`.
//
// If `attr` is non-NULL, the resulting `X509_ATTRIBUTE` is also written to
// `*attr`. If `*attr` was non-NULL when the function was called, `*attr` is
// reused instead of creating a new object.
//
// WARNING: The interpretation of `attrtype`, `data`, and `len` is complex and
// error-prone. See `X509_ATTRIBUTE_set1_data` for details.
//
// WARNING: The object reuse form is deprecated and may be removed in the
// future. It also currently incorrectly appends to the reused object's value
// set rather than overwriting it.
OPENSSL_EXPORT X509_ATTRIBUTE *X509_ATTRIBUTE_create_by_NID(
    X509_ATTRIBUTE **attr, int nid, int attrtype, const void *data, int len);

// X509_ATTRIBUTE_create_by_OBJ behaves like `X509_ATTRIBUTE_create_by_NID`
// except the attribute's type is determined by `obj`.
OPENSSL_EXPORT X509_ATTRIBUTE *X509_ATTRIBUTE_create_by_OBJ(
    X509_ATTRIBUTE **attr, const ASN1_OBJECT *obj, int attrtype,
    const void *data, int len);

// X509_ATTRIBUTE_create_by_txt behaves like `X509_ATTRIBUTE_create_by_NID`
// except the attribute's type is determined by calling `OBJ_txt2obj` with
// `attrname`.
OPENSSL_EXPORT X509_ATTRIBUTE *X509_ATTRIBUTE_create_by_txt(
    X509_ATTRIBUTE **attr, const char *attrname, int type,
    const unsigned char *bytes, int len);

// X509_ATTRIBUTE_set1_object sets `attr`'s type to `obj`. It returns one on
// success and zero on error.
OPENSSL_EXPORT int X509_ATTRIBUTE_set1_object(X509_ATTRIBUTE *attr,
                                              const ASN1_OBJECT *obj);

// X509_ATTRIBUTE_set1_data appends a value to `attr`'s value set and returns
// one on success or zero on error. The value is determined as follows:
//
// If `attrtype` is zero, this function returns one and does nothing. This form
// may be used when calling `X509_ATTRIBUTE_create_by_*` to create an attribute
// with an empty value set. Such attributes are invalid, but OpenSSL supports
// creating them.
//
// Otherwise, if `attrtype` is a `MBSTRING_*` constant, the value is an ASN.1
// string. The string is determined by decoding `len` bytes from `data` in the
// encoding specified by `attrtype`, and then re-encoding it in a form
// appropriate for `attr`'s type. If `len` is -1, `strlen(data)` is used
// instead. See `ASN1_STRING_set_by_NID` for details.
//
// Otherwise, if `len` is not -1, the value is an ASN.1 string. `attrtype` is an
// `ASN1_STRING` type value and the `len` bytes from `data` are copied as the
// type-specific representation of `ASN1_STRING`. See `ASN1_STRING` for details.
//
// Otherwise, if `len` is -1, the value is constructed by passing `attrtype` and
// `data` to `ASN1_TYPE_set1`. That is, `attrtype` is an `ASN1_TYPE` type value,
// and `data` is cast to the corresponding pointer type.
//
// WARNING: Despite the name, this function appends to `attr`'s value set,
// rather than overwriting it. To overwrite the value set, create a new
// `X509_ATTRIBUTE` with `X509_ATTRIBUTE_new`.
//
// WARNING: If using the `MBSTRING_*` form, pass a length rather than relying on
// `strlen`. In particular, `strlen` will not behave correctly if the input is
// `MBSTRING_BMP` or `MBSTRING_UNIV`.
//
// WARNING: This function currently misinterprets `V_ASN1_OTHER` as an
// `MBSTRING_*` constant. This matches OpenSSL but means it is impossible to
// construct a value with a non-universal tag.
OPENSSL_EXPORT int X509_ATTRIBUTE_set1_data(X509_ATTRIBUTE *attr, int attrtype,
                                            const void *data, int len);

// X509_ATTRIBUTE_get0_data returns the `idx`th value of `attr` in a
// type-specific representation to `attrtype`, or NULL if out of bounds or the
// type does not match. `attrtype` is one of the type values in `ASN1_TYPE`. On
// match, the return value uses the same representation as `ASN1_TYPE_set0`. See
// `ASN1_TYPE` for details.
OPENSSL_EXPORT void *X509_ATTRIBUTE_get0_data(X509_ATTRIBUTE *attr, int idx,
                                              int attrtype, void *unused);

// X509_ATTRIBUTE_count returns the number of values in `attr`.
OPENSSL_EXPORT int X509_ATTRIBUTE_count(const X509_ATTRIBUTE *attr);

// X509_ATTRIBUTE_get0_object returns the type of `attr`.
OPENSSL_EXPORT ASN1_OBJECT *X509_ATTRIBUTE_get0_object(X509_ATTRIBUTE *attr);

// X509_ATTRIBUTE_get0_type returns the `idx`th value in `attr`, or NULL if out
// of bounds. Note this function returns one of `attr`'s values, not the type.
OPENSSL_EXPORT ASN1_TYPE *X509_ATTRIBUTE_get0_type(X509_ATTRIBUTE *attr,
                                                   int idx);


// Certificate stores.
//
// An `X509_STORE` contains trusted certificates, CRLs, and verification
// parameters that are shared between multiple certificate verifications.
//
// Certificates in an `X509_STORE` are referred to as "trusted certificates",
// but an individual certificate verification may not necessarily treat every
// trusted certificate as a trust anchor. See `X509_VERIFY_PARAM_set_trust` for
// details.
//
// WARNING: Although a trusted certificate which fails the
// `X509_VERIFY_PARAM_set_trust` check is functionally an untrusted
// intermediate certificate, callers should not rely on this to configure
// untrusted intermediates in an `X509_STORE`. The trust check is complex, so
// this risks inadvertently treating it as a trust anchor. Instead, configure
// untrusted intermediates with the `chain` parameter of `X509_STORE_CTX_init`.
//
// Certificates in `X509_STORE` may be specified in several ways:
// - Added by `X509_STORE_add_cert`.
// - Returned by an `X509_LOOKUP` added by `X509_STORE_add_lookup`.
//
// `X509_STORE`s are reference-counted and may be shared by certificate
// verifications running concurrently on multiple threads. However, an
// `X509_STORE`'s verification parameters may not be modified concurrently with
// certificate verification or other operations. Unless otherwise documented,
// functions which take const pointer may be used concurrently, while
// functions which take a non-const pointer may not. Callers that wish to modify
// verification parameters in a shared `X509_STORE` should instead modify
// `X509_STORE_CTX`s individually.
//
// Objects in an `X509_STORE` are represented as an `X509_OBJECT`. Some
// functions in this library return values with this type.

// X509_STORE_new returns a newly-allocated `X509_STORE`, or NULL on error.
OPENSSL_EXPORT X509_STORE *X509_STORE_new(void);

// X509_STORE_up_ref adds one to the reference count of `store` and returns one.
// Although `store` is not const, this function's use of `store` is thread-safe.
OPENSSL_EXPORT int X509_STORE_up_ref(X509_STORE *store);

// X509_STORE_free releases memory associated with `store`.
OPENSSL_EXPORT void X509_STORE_free(X509_STORE *store);

// X509_STORE_add_cert adds `x509` to `store` as a trusted certificate. It
// returns one on success and zero on error. This function internally increments
// `x509`'s reference count, so the caller retains ownership of `x509`.
//
// Certificates configured by this function are still subject to the checks
// described in `X509_VERIFY_PARAM_set_trust`.
//
// Although `store` is not const, this function's use of `store` is thread-safe.
// However, if this function is called concurrently with `X509_verify_cert`, it
// is a race condition whether `x509` is available for issuer lookups.
// Moreover, the result may differ for each issuer lookup performed by a single
// `X509_verify_cert` call.
OPENSSL_EXPORT int X509_STORE_add_cert(X509_STORE *store, X509 *x509);

// X509_STORE_add_crl adds `crl` to `store`. It returns one on success and zero
// on error. This function internally increments `crl`'s reference count, so the
// caller retains ownership of `crl`. CRLs added in this way are candidates for
// CRL lookup when `X509_V_FLAG_CRL_CHECK` is set.
//
// Although `store` is not const, this function's use of `store` is thread-safe.
// However, if this function is called concurrently with `X509_verify_cert`, it
// is a race condition whether `crl` is available for CRL checks. Moreover, the
// result may differ for each CRL check performed by a single
// `X509_verify_cert` call.
//
// Note there are no supported APIs to remove CRLs from `store` once inserted.
// To vary the set of CRLs over time, callers should either create a new
// `X509_STORE` or configure CRLs on a per-verification basis with
// `X509_STORE_CTX_set0_crls`.
OPENSSL_EXPORT int X509_STORE_add_crl(X509_STORE *store, X509_CRL *crl);

// X509_STORE_get0_param returns `store`'s verification parameters. This object
// is mutable and may be modified by the caller. For an individual certificate
// verification operation, `X509_STORE_CTX_init` initializes the
// `X509_STORE_CTX`'s parameters with these parameters.
//
// WARNING: `X509_STORE_CTX_init` applies some default parameters (as in
// `X509_VERIFY_PARAM_inherit`) after copying `store`'s parameters. This means
// it is impossible to leave some parameters unset at `store`. They must be
// explicitly unset after creating the `X509_STORE_CTX`.
//
// As of writing these late defaults are a depth limit (see
// `X509_VERIFY_PARAM_set_depth`) and the `X509_V_FLAG_TRUSTED_FIRST` flag. This
// warning does not apply if the parameters were set in `store`.
//
// TODO(crbug.com/boringssl/441): This behavior is very surprising. Can we
// remove this notion of late defaults? The unsettable value at `X509_STORE` is
// -1, which rejects everything but explicitly-trusted self-signed certificates.
// `X509_V_FLAG_TRUSTED_FIRST` is mostly a workaround for poor path-building.
OPENSSL_EXPORT X509_VERIFY_PARAM *X509_STORE_get0_param(X509_STORE *store);

// X509_STORE_set1_param copies verification parameters from `param` as in
// `X509_VERIFY_PARAM_set1`. It returns one on success and zero on error.
OPENSSL_EXPORT int X509_STORE_set1_param(X509_STORE *store,
                                         const X509_VERIFY_PARAM *param);

// X509_STORE_set_flags enables all values in `flags` in `store`'s verification
// flags. `flags` should be a combination of `X509_V_FLAG_*` constants.
//
// WARNING: These flags will be combined with default flags when copied to an
// `X509_STORE_CTX`. This means it is impossible to unset those defaults from
// the `X509_STORE`. See discussion in `X509_STORE_get0_param`.
OPENSSL_EXPORT int X509_STORE_set_flags(X509_STORE *store, unsigned long flags);

// X509_STORE_set_depth configures `store` to, by default, limit certificate
// chains to `depth` intermediate certificates. This count excludes both the
// target certificate and the trust anchor (root certificate).
OPENSSL_EXPORT int X509_STORE_set_depth(X509_STORE *store, int depth);

// X509_STORE_set_purpose configures the purpose check for `store`. See
// `X509_VERIFY_PARAM_set_purpose` for details.
OPENSSL_EXPORT int X509_STORE_set_purpose(X509_STORE *store, int purpose);

// X509_STORE_set_trust configures the trust check for `store`. See
// `X509_VERIFY_PARAM_set_trust` for details.
OPENSSL_EXPORT int X509_STORE_set_trust(X509_STORE *store, int trust);

// The following constants indicate the type of an `X509_OBJECT`.
#define X509_LU_NONE 0
#define X509_LU_X509 1
#define X509_LU_CRL 2
#define X509_LU_PKEY 3

DEFINE_STACK_OF(X509_OBJECT)

// X509_OBJECT_new returns a newly-allocated, empty `X509_OBJECT` or NULL on
// error.
OPENSSL_EXPORT X509_OBJECT *X509_OBJECT_new(void);

// X509_OBJECT_free releases memory associated with `obj`.
OPENSSL_EXPORT void X509_OBJECT_free(X509_OBJECT *obj);

// X509_OBJECT_get_type returns the type of `obj`, which will be one of the
// `X509_LU_*` constants.
OPENSSL_EXPORT int X509_OBJECT_get_type(const X509_OBJECT *obj);

// X509_OBJECT_get0_X509 returns `obj` as a certificate, or NULL if `obj` is not
// a certificate.
OPENSSL_EXPORT X509 *X509_OBJECT_get0_X509(const X509_OBJECT *obj);

// X509_STORE_get1_objects returns a newly-allocated stack containing the
// contents of `store`, or NULL on error. The caller must release the result
// with `sk_X509_OBJECT_pop_free` and `X509_OBJECT_free` when done.
//
// The result will include all certificates and CRLs added via
// `X509_STORE_add_cert` and `X509_STORE_add_crl`, as well as any cached objects
// added by `X509_LOOKUP_add_dir`. The last of these may change over time, as
// different objects are loaded from the filesystem. Callers should not depend
// on this caching behavior. The objects are returned in no particular order.
OPENSSL_EXPORT STACK_OF(X509_OBJECT) *X509_STORE_get1_objects(
    X509_STORE *store);


// Certificate verification.
//
// An `X509_STORE_CTX` object represents a single certificate verification
// operation. To verify a certificate chain, callers construct an
// `X509_STORE_CTX`, initialize it with `X509_STORE_CTX_init`, configure extra
// parameters with `X509_STORE_CTX_get0_param`, and call `X509_verify_cert`.

// X509_STORE_CTX_new returns a newly-allocated, empty `X509_STORE_CTX`, or NULL
// on error.
OPENSSL_EXPORT X509_STORE_CTX *X509_STORE_CTX_new(void);

// X509_STORE_CTX_free releases memory associated with `ctx`.
OPENSSL_EXPORT void X509_STORE_CTX_free(X509_STORE_CTX *ctx);

// X509_STORE_CTX_init initializes `ctx` to verify `x509`, using trusted
// certificates and parameters in `store`. It returns one on success and zero on
// error. `chain` is a list of untrusted intermediate certificates to use in
// verification.
//
// `ctx` stores pointers to `store`, `x509`, and `chain`. Each of these objects
// must outlive `ctx` and may not be mutated for the duration of the certificate
// verification.
OPENSSL_EXPORT int X509_STORE_CTX_init(X509_STORE_CTX *ctx, X509_STORE *store,
                                       X509 *x509, STACK_OF(X509) *chain);

// X509_verify_cert performs certificate verification with `ctx`, which must
// have been initialized with `X509_STORE_CTX_init`. It returns one on success
// and zero on error. On success, `X509_STORE_CTX_get0_chain` or
// `X509_STORE_CTX_get1_chain` may be used to return the verified certificate
// chain. On error, `X509_STORE_CTX_get_error` may be used to return additional
// error information.
//
// WARNING: Most failure conditions from this function do not use the error
// queue. Use `X509_STORE_CTX_get_error` to determine the cause of the error.
OPENSSL_EXPORT int X509_verify_cert(X509_STORE_CTX *ctx);

// X509_STORE_CTX_get0_chain, after a successful `X509_verify_cert` call,
// returns the verified certificate chain. The chain begins with the leaf and
// ends with trust anchor.
//
// At other points, such as after a failed verification or during the deprecated
// verification callback, it returns the partial chain built so far. Callers
// should avoid relying on this as this exposes unstable library implementation
// details.
OPENSSL_EXPORT STACK_OF(X509) *X509_STORE_CTX_get0_chain(
    const X509_STORE_CTX *ctx);

// X509_STORE_CTX_get1_chain behaves like `X509_STORE_CTX_get0_chain` but
// returns a newly-allocated `STACK_OF(X509)` containing the completed chain,
// with each certificate's reference count incremented. Callers must free the
// result with `sk_X509_pop_free` and `X509_free` when done.
OPENSSL_EXPORT STACK_OF(X509) *X509_STORE_CTX_get1_chain(
    const X509_STORE_CTX *ctx);

// The following values are possible outputs of `X509_STORE_CTX_get_error`.
#define X509_V_OK 0
#define X509_V_ERR_UNSPECIFIED 1
#define X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT 2
#define X509_V_ERR_UNABLE_TO_GET_CRL 3
#define X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE 4
#define X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE 5
#define X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY 6
#define X509_V_ERR_CERT_SIGNATURE_FAILURE 7
#define X509_V_ERR_CRL_SIGNATURE_FAILURE 8
#define X509_V_ERR_CERT_NOT_YET_VALID 9
#define X509_V_ERR_CERT_HAS_EXPIRED 10
#define X509_V_ERR_CRL_NOT_YET_VALID 11
#define X509_V_ERR_CRL_HAS_EXPIRED 12
#define X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD 13
#define X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD 14
#define X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD 15
#define X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD 16
#define X509_V_ERR_OUT_OF_MEM 17
#define X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT 18
#define X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN 19
#define X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY 20
#define X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE 21
#define X509_V_ERR_CERT_CHAIN_TOO_LONG 22
#define X509_V_ERR_CERT_REVOKED 23
#define X509_V_ERR_INVALID_CA 24
#define X509_V_ERR_PATH_LENGTH_EXCEEDED 25
#define X509_V_ERR_INVALID_PURPOSE 26
#define X509_V_ERR_CERT_UNTRUSTED 27
#define X509_V_ERR_CERT_REJECTED 28
#define X509_V_ERR_SUBJECT_ISSUER_MISMATCH 29
#define X509_V_ERR_AKID_SKID_MISMATCH 30
#define X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH 31
#define X509_V_ERR_KEYUSAGE_NO_CERTSIGN 32
#define X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER 33
#define X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION 34
#define X509_V_ERR_KEYUSAGE_NO_CRL_SIGN 35
#define X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION 36
#define X509_V_ERR_INVALID_NON_CA 37
#define X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED 38
#define X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE 39
#define X509_V_ERR_PROXY_CERTIFICATES_NOT_ALLOWED 40
#define X509_V_ERR_INVALID_EXTENSION 41
#define X509_V_ERR_INVALID_POLICY_EXTENSION 42
#define X509_V_ERR_NO_EXPLICIT_POLICY 43
#define X509_V_ERR_DIFFERENT_CRL_SCOPE 44
#define X509_V_ERR_UNSUPPORTED_EXTENSION_FEATURE 45
#define X509_V_ERR_UNNESTED_RESOURCE 46
#define X509_V_ERR_PERMITTED_VIOLATION 47
#define X509_V_ERR_EXCLUDED_VIOLATION 48
#define X509_V_ERR_SUBTREE_MINMAX 49
#define X509_V_ERR_APPLICATION_VERIFICATION 50
#define X509_V_ERR_UNSUPPORTED_CONSTRAINT_TYPE 51
#define X509_V_ERR_UNSUPPORTED_CONSTRAINT_SYNTAX 52
#define X509_V_ERR_UNSUPPORTED_NAME_SYNTAX 53
#define X509_V_ERR_CRL_PATH_VALIDATION_ERROR 54
#define X509_V_ERR_HOSTNAME_MISMATCH 62
#define X509_V_ERR_EMAIL_MISMATCH 63
#define X509_V_ERR_IP_ADDRESS_MISMATCH 64
#define X509_V_ERR_INVALID_CALL 65
#define X509_V_ERR_STORE_LOOKUP 66
#define X509_V_ERR_NAME_CONSTRAINTS_WITHOUT_SANS 67

// X509_STORE_CTX_get_error, after `X509_verify_cert` returns, returns
// `X509_V_OK` if verification succeeded or an `X509_V_ERR_*` describing why
// verification failed. This will be consistent with `X509_verify_cert`'s return
// value, unless the caller used the deprecated verification callback (see
// `X509_STORE_CTX_set_verify_cb`) in a way that breaks `ctx`'s invariants.
//
// If called during the deprecated verification callback when `ok` is zero, it
// returns the current error under consideration.
OPENSSL_EXPORT int X509_STORE_CTX_get_error(const X509_STORE_CTX *ctx);

// X509_STORE_CTX_set_error sets `ctx`'s error to `err`, which should be
// `X509_V_OK` or an `X509_V_ERR_*` constant. It is not expected to be called in
// typical `X509_STORE_CTX` usage, but may be used in callback APIs where
// applications synthesize `X509_STORE_CTX` error conditions. See also
// `X509_STORE_CTX_set_verify_cb` and `SSL_CTX_set_cert_verify_callback`.
OPENSSL_EXPORT void X509_STORE_CTX_set_error(X509_STORE_CTX *ctx, int err);

// X509_verify_cert_error_string returns `err` as a human-readable string, where
// `err` should be one of the `X509_V_*` values. If `err` is unknown, it returns
// a default description.
OPENSSL_EXPORT const char *X509_verify_cert_error_string(long err);

// X509_STORE_CTX_get_error_depth returns the depth at which the error returned
// by `X509_STORE_CTX_get_error` occurred. This is zero-indexed integer into the
// certificate chain. Zero indicates the target certificate, one its issuer, and
// so on.
OPENSSL_EXPORT int X509_STORE_CTX_get_error_depth(const X509_STORE_CTX *ctx);

// X509_STORE_CTX_get_current_cert returns the certificate which caused the
// error returned by `X509_STORE_CTX_get_error`.
OPENSSL_EXPORT X509 *X509_STORE_CTX_get_current_cert(const X509_STORE_CTX *ctx);

// X509_STORE_CTX_get0_current_crl returns the CRL which caused the error
// returned by `X509_STORE_CTX_get_error`.
OPENSSL_EXPORT X509_CRL *X509_STORE_CTX_get0_current_crl(
    const X509_STORE_CTX *ctx);

// X509_STORE_CTX_get0_store returns the `X509_STORE` that `ctx` uses.
OPENSSL_EXPORT X509_STORE *X509_STORE_CTX_get0_store(const X509_STORE_CTX *ctx);

// X509_STORE_CTX_get0_cert returns the leaf certificate that `ctx` is
// verifying.
OPENSSL_EXPORT X509 *X509_STORE_CTX_get0_cert(const X509_STORE_CTX *ctx);

// X509_STORE_CTX_get0_untrusted returns the stack of untrusted intermediates
// used by `ctx` for certificate verification.
OPENSSL_EXPORT STACK_OF(X509) *X509_STORE_CTX_get0_untrusted(
    const X509_STORE_CTX *ctx);

// X509_STORE_CTX_set0_trusted_stack configures `ctx` to trust the certificates
// in `sk`. `sk` must remain valid for the duration of `ctx`. Calling this
// function causes `ctx` to ignore any certificates configured in the
// `X509_STORE`. Certificates in `sk` are still subject to the check described
// in `X509_VERIFY_PARAM_set_trust`.
//
// WARNING: This function differs from most `set0` functions in that it does not
// take ownership of its input. The caller is required to ensure the lifetimes
// are consistent.
OPENSSL_EXPORT void X509_STORE_CTX_set0_trusted_stack(X509_STORE_CTX *ctx,
                                                      STACK_OF(X509) *sk);

// X509_STORE_CTX_set0_crls configures `ctx` to consider the CRLs in `sk` as
// candidates for CRL lookup. `sk` must remain valid for the duration of `ctx`.
// These CRLs are considered in addition to CRLs found in `X509_STORE`.
//
// WARNING: This function differs from most `set0` functions in that it does not
// take ownership of its input. The caller is required to ensure the lifetimes
// are consistent.
OPENSSL_EXPORT void X509_STORE_CTX_set0_crls(X509_STORE_CTX *ctx,
                                             STACK_OF(X509_CRL) *sk);

// X509_STORE_CTX_set_default looks up the set of parameters named `name` and
// applies those default verification parameters for `ctx`. As in
// `X509_VERIFY_PARAM_inherit`, only unset parameters are changed. This function
// returns one on success and zero on error.
//
// The supported values of `name` are:
// - "default" is an internal value which configures some late defaults. See the
//   discussion in `X509_STORE_get0_param`.
// - "pkcs7" configures default trust and purpose checks for PKCS#7 signatures.
// - "smime_sign" configures trust and purpose checks for S/MIME signatures.
// - "ssl_client" configures trust and purpose checks for TLS clients.
// - "ssl_server" configures trust and purpose checks for TLS servers.
//
// TODO(crbug.com/boringssl/441): Make "default" a no-op.
OPENSSL_EXPORT int X509_STORE_CTX_set_default(X509_STORE_CTX *ctx,
                                              const char *name);

// X509_STORE_CTX_get0_param returns `ctx`'s verification parameters. This
// object is mutable and may be modified by the caller.
OPENSSL_EXPORT X509_VERIFY_PARAM *X509_STORE_CTX_get0_param(
    X509_STORE_CTX *ctx);

// X509_STORE_CTX_set0_param returns `ctx`'s verification parameters to `param`
// and takes ownership of `param`. After this function returns, the caller
// should not free `param`.
//
// WARNING: This function discards any values which were previously applied in
// `ctx`, including the "default" parameters applied late in
// `X509_STORE_CTX_init`. These late defaults are not applied to parameters
// created standalone by `X509_VERIFY_PARAM_new`.
//
// TODO(crbug.com/boringssl/441): This behavior is very surprising. Should we
// re-apply the late defaults in `param`, or somehow avoid this notion of late
// defaults altogether?
OPENSSL_EXPORT void X509_STORE_CTX_set0_param(X509_STORE_CTX *ctx,
                                              X509_VERIFY_PARAM *param);

// X509_STORE_CTX_set_flags enables all values in `flags` in `ctx`'s
// verification flags. `flags` should be a combination of `X509_V_FLAG_*`
// constants.
OPENSSL_EXPORT void X509_STORE_CTX_set_flags(X509_STORE_CTX *ctx,
                                             unsigned long flags);

// X509_STORE_CTX_set_time configures certificate verification to use `t`
// instead of the current time. `flags` is ignored and should be zero.
OPENSSL_EXPORT void X509_STORE_CTX_set_time(X509_STORE_CTX *ctx,
                                            unsigned long flags, time_t t);

// X509_STORE_CTX_set_time_posix configures certificate verification to use `t`
// instead of the current time. `t` is interpreted as a POSIX timestamp in
// seconds. `flags` is ignored and should be zero.
OPENSSL_EXPORT void X509_STORE_CTX_set_time_posix(X509_STORE_CTX *ctx,
                                                  unsigned long flags,
                                                  int64_t t);

// X509_STORE_CTX_set_depth configures `ctx` to, by default, limit certificate
// chains to `depth` intermediate certificates. This count excludes both the
// target certificate and the trust anchor (root certificate).
OPENSSL_EXPORT void X509_STORE_CTX_set_depth(X509_STORE_CTX *ctx, int depth);

// X509_STORE_CTX_set_purpose simultaneously configures `ctx`'s purpose and
// trust checks, if unset. It returns one on success and zero if `purpose` is
// not a valid purpose value. `purpose` should be an `X509_PURPOSE_*` constant.
// If so, it configures `ctx` with a purpose check of `purpose` and a trust
// check of `purpose`'s corresponding trust value. If either the purpose or
// trust check had already been specified for `ctx`, that corresponding
// modification is silently dropped.
//
// See `X509_VERIFY_PARAM_set_purpose` and `X509_VERIFY_PARAM_set_trust` for
// details on the purpose and trust checks, respectively.
//
// If `purpose` is `X509_PURPOSE_ANY`, this function returns an error because it
// has no corresponding `X509_TRUST_*` value. It is not possible to set
// `X509_PURPOSE_ANY` with this function, only `X509_VERIFY_PARAM_set_purpose`.
//
// WARNING: Unlike similarly named functions in this header, this function
// silently does not behave the same as `X509_VERIFY_PARAM_set_purpose`. Callers
// may use `X509_VERIFY_PARAM_set_purpose` with `X509_STORE_CTX_get0_param` to
// avoid this difference.
OPENSSL_EXPORT int X509_STORE_CTX_set_purpose(X509_STORE_CTX *ctx, int purpose);

// X509_STORE_CTX_set_trust configures `ctx`'s trust check, if unset. It returns
// one on success and zero if `trust` is not a valid trust value. `trust` should
// be an `X509_TRUST_*` constant. If so, it configures `ctx` with a trust check
// of `trust`. If the trust check had already been specified for `ctx`, it
// silently does nothing.
//
// See `X509_VERIFY_PARAM_set_trust` for details on the purpose and trust check.
//
// WARNING: Unlike similarly named functions in this header, this function
// does not behave the same as `X509_VERIFY_PARAM_set_trust`. Callers may use
// `X509_VERIFY_PARAM_set_trust` with `X509_STORE_CTX_get0_param` to avoid this
// difference.
OPENSSL_EXPORT int X509_STORE_CTX_set_trust(X509_STORE_CTX *ctx, int trust);


// Verification parameters.
//
// An `X509_VERIFY_PARAM` contains a set of parameters for certificate
// verification.

// X509_VERIFY_PARAM_new returns a newly-allocated `X509_VERIFY_PARAM`, or NULL
// on error.
OPENSSL_EXPORT X509_VERIFY_PARAM *X509_VERIFY_PARAM_new(void);

// X509_VERIFY_PARAM_free releases memory associated with `param`.
OPENSSL_EXPORT void X509_VERIFY_PARAM_free(X509_VERIFY_PARAM *param);

// X509_VERIFY_PARAM_inherit applies `from` as the default values for `to`. That
// is, for each parameter that is unset in `to`, it copies the value in `from`.
// This function returns one on success and zero on error.
OPENSSL_EXPORT int X509_VERIFY_PARAM_inherit(X509_VERIFY_PARAM *to,
                                             const X509_VERIFY_PARAM *from);

// X509_VERIFY_PARAM_set1 copies parameters from `from` to `to`. If a parameter
// is unset in `from`, the existing value in `to` is preserved. This function
// returns one on success and zero on error.
OPENSSL_EXPORT int X509_VERIFY_PARAM_set1(X509_VERIFY_PARAM *to,
                                          const X509_VERIFY_PARAM *from);

// X509_V_FLAG_* are flags for `X509_VERIFY_PARAM_set_flags` and
// `X509_VERIFY_PARAM_clear_flags`.

// X509_V_FLAG_CB_ISSUER_CHECK causes the deprecated verify callback (see
// `X509_STORE_CTX_set_verify_cb`) to be called for errors while matching
// subject and issuer certificates.
#define X509_V_FLAG_CB_ISSUER_CHECK 0x1
// X509_V_FLAG_USE_CHECK_TIME is an internal flag used to track whether
// `X509_STORE_CTX_set_time` has been used. If cleared, the system time is
// restored.
#define X509_V_FLAG_USE_CHECK_TIME 0x2
// X509_V_FLAG_CRL_CHECK enables CRL lookup and checking for the leaf.
#define X509_V_FLAG_CRL_CHECK 0x4
// X509_V_FLAG_CRL_CHECK_ALL enables CRL lookup and checking for the entire
// certificate chain. `X509_V_FLAG_CRL_CHECK` must be set for this flag to take
// effect.
#define X509_V_FLAG_CRL_CHECK_ALL 0x8
// X509_V_FLAG_IGNORE_CRITICAL ignores unhandled critical extensions. Do not use
// this option. Critical extensions ensure the verifier does not bypass
// unrecognized security restrictions in certificates.
#define X509_V_FLAG_IGNORE_CRITICAL 0x10
// X509_V_FLAG_X509_STRICT does nothing. Its functionality has been enabled by
// default.
#define X509_V_FLAG_X509_STRICT 0x00
// X509_V_FLAG_ALLOW_PROXY_CERTS does nothing. Proxy certificate support has
// been removed.
#define X509_V_FLAG_ALLOW_PROXY_CERTS 0x40
// X509_V_FLAG_POLICY_CHECK does nothing. Policy checking is always enabled.
#define X509_V_FLAG_POLICY_CHECK 0x80
// X509_V_FLAG_EXPLICIT_POLICY requires some policy OID to be asserted by the
// final certificate chain. See initial-explicit-policy from RFC 5280,
// section 6.1.1.
#define X509_V_FLAG_EXPLICIT_POLICY 0x100
// X509_V_FLAG_INHIBIT_ANY inhibits the anyPolicy OID. See
// initial-any-policy-inhibit from RFC 5280, section 6.1.1.
#define X509_V_FLAG_INHIBIT_ANY 0x200
// X509_V_FLAG_INHIBIT_MAP inhibits policy mapping. See
// initial-policy-mapping-inhibit from RFC 5280, section 6.1.1.
#define X509_V_FLAG_INHIBIT_MAP 0x400
// X509_V_FLAG_NOTIFY_POLICY does nothing. Its functionality has been removed.
#define X509_V_FLAG_NOTIFY_POLICY 0x800
// X509_V_FLAG_EXTENDED_CRL_SUPPORT causes all verifications to fail. Extended
// CRL features have been removed.
#define X509_V_FLAG_EXTENDED_CRL_SUPPORT 0x1000
// X509_V_FLAG_USE_DELTAS causes all verifications to fail. Delta CRL support
// has been removed.
#define X509_V_FLAG_USE_DELTAS 0x2000
// X509_V_FLAG_CHECK_SS_SIGNATURE checks the redundant signature on self-signed
// trust anchors. This check provides no security benefit and only wastes CPU.
#define X509_V_FLAG_CHECK_SS_SIGNATURE 0x4000
// X509_V_FLAG_TRUSTED_FIRST, during path-building, checks for a match in the
// trust store before considering an untrusted intermediate. This flag is
// enabled by default.
#define X509_V_FLAG_TRUSTED_FIRST 0x8000
// X509_V_FLAG_PARTIAL_CHAIN treats all trusted certificates as trust anchors,
// independent of the `X509_VERIFY_PARAM_set_trust` setting.
#define X509_V_FLAG_PARTIAL_CHAIN 0x80000
// X509_V_FLAG_NO_ALT_CHAINS disables building alternative chains if the initial
// one was rejected.
#define X509_V_FLAG_NO_ALT_CHAINS 0x100000
// X509_V_FLAG_NO_CHECK_TIME disables all time checks in certificate
// verification.
#define X509_V_FLAG_NO_CHECK_TIME 0x200000

// X509_VERIFY_PARAM_set_flags enables all values in `flags` in `param`'s
// verification flags and returns one. `flags` should be a combination of
// `X509_V_FLAG_*` constants.
OPENSSL_EXPORT int X509_VERIFY_PARAM_set_flags(X509_VERIFY_PARAM *param,
                                               unsigned long flags);

// X509_VERIFY_PARAM_clear_flags disables all values in `flags` in `param`'s
// verification flags and returns one. `flags` should be a combination of
// `X509_V_FLAG_*` constants.
OPENSSL_EXPORT int X509_VERIFY_PARAM_clear_flags(X509_VERIFY_PARAM *param,
                                                 unsigned long flags);

// X509_VERIFY_PARAM_get_flags returns `param`'s verification flags.
OPENSSL_EXPORT unsigned long X509_VERIFY_PARAM_get_flags(
    const X509_VERIFY_PARAM *param);

// X509_VERIFY_PARAM_set_depth configures `param` to limit certificate chains to
// `depth` intermediate certificates. This count excludes both the target
// certificate and the trust anchor (root certificate).
OPENSSL_EXPORT void X509_VERIFY_PARAM_set_depth(X509_VERIFY_PARAM *param,
                                                int depth);

// X509_VERIFY_PARAM_get_depth returns the maximum depth configured in `param`.
// See `X509_VERIFY_PARAM_set_depth`.
OPENSSL_EXPORT int X509_VERIFY_PARAM_get_depth(const X509_VERIFY_PARAM *param);

// X509_VERIFY_PARAM_set_time configures certificate verification to use `t`
// instead of the current time.
OPENSSL_EXPORT void X509_VERIFY_PARAM_set_time(X509_VERIFY_PARAM *param,
                                               time_t t);

// X509_VERIFY_PARAM_set_time_posix configures certificate verification to use
// `t` instead of the current time. `t` is interpreted as a POSIX timestamp in
// seconds.
OPENSSL_EXPORT void X509_VERIFY_PARAM_set_time_posix(X509_VERIFY_PARAM *param,
                                                     int64_t t);

// X509_VERIFY_PARAM_add0_policy adds `policy` to the user-initial-policy-set
// (see Section 6.1.1 of RFC 5280). On success, it takes ownership of
// `policy` and returns one. Otherwise, it returns zero and the caller retains
// ownership of `policy`.
OPENSSL_EXPORT int X509_VERIFY_PARAM_add0_policy(X509_VERIFY_PARAM *param,
                                                 ASN1_OBJECT *policy);

// X509_VERIFY_PARAM_set1_policies sets the user-initial-policy-set (see
// Section 6.1.1 of RFC 5280) to a copy of `policies`. It returns one on success
// and zero on error.
OPENSSL_EXPORT int X509_VERIFY_PARAM_set1_policies(
    X509_VERIFY_PARAM *param, const STACK_OF(ASN1_OBJECT) *policies);

// X509_VERIFY_PARAM_set1_host configures `param` to check for the DNS name
// specified by `name`. It returns one on success and zero on error.
//
// By default, both subject alternative names and the subject's common name
// attribute are checked. The latter has long been deprecated, so callers should
// call `X509_VERIFY_PARAM_set_hostflags` with
// `X509_CHECK_FLAG_NEVER_CHECK_SUBJECT` to use the standard behavior.
// https://crbug.com/boringssl/464 tracks fixing the default.
OPENSSL_EXPORT int X509_VERIFY_PARAM_set1_host(X509_VERIFY_PARAM *param,
                                               const char *name,
                                               size_t name_len);

// X509_VERIFY_PARAM_add1_host adds `name` to the list of names checked by
// `param`. If any configured DNS name matches the certificate, verification
// succeeds. It returns one on success and zero on error.
//
// By default, both subject alternative names and the subject's common name
// attribute are checked. The latter has long been deprecated, so callers should
// call `X509_VERIFY_PARAM_set_hostflags` with
// `X509_CHECK_FLAG_NEVER_CHECK_SUBJECT` to use the standard behavior.
// https://crbug.com/boringssl/464 tracks fixing the default.
OPENSSL_EXPORT int X509_VERIFY_PARAM_add1_host(X509_VERIFY_PARAM *param,
                                               const char *name,
                                               size_t name_len);

// X509_CHECK_FLAG_NO_WILDCARDS disables wildcard matching for DNS names.
#define X509_CHECK_FLAG_NO_WILDCARDS 0x2

// X509_CHECK_FLAG_NEVER_CHECK_SUBJECT disables the subject fallback, normally
// enabled when subjectAltNames is missing.
#define X509_CHECK_FLAG_NEVER_CHECK_SUBJECT 0x20

// X509_VERIFY_PARAM_set_hostflags sets the name-checking flags on `param` to
// `flags`. `flags` should be a combination of `X509_CHECK_FLAG_*` constants.
OPENSSL_EXPORT void X509_VERIFY_PARAM_set_hostflags(X509_VERIFY_PARAM *param,
                                                    unsigned int flags);

// X509_VERIFY_PARAM_set1_email configures `param` to check for the email
// address specified by `email`. It returns one on success and zero on error.
//
// By default, both subject alternative names and the subject's email address
// attribute are checked. The `X509_CHECK_FLAG_NEVER_CHECK_SUBJECT` flag may be
// used to change this behavior.
OPENSSL_EXPORT int X509_VERIFY_PARAM_set1_email(X509_VERIFY_PARAM *param,
                                                const char *email,
                                                size_t email_len);

// X509_VERIFY_PARAM_set1_ip configures `param` to check for the IP address
// specified by `ip`. It returns one on success and zero on error. The IP
// address is specified in its binary representation. `ip_len` must be 4 for an
// IPv4 address and 16 for an IPv6 address.
OPENSSL_EXPORT int X509_VERIFY_PARAM_set1_ip(X509_VERIFY_PARAM *param,
                                             const uint8_t *ip, size_t ip_len);

// X509_VERIFY_PARAM_set1_ip_asc decodes `ipasc` as the ASCII representation of
// an IPv4 or IPv6 address, and configures `param` to check for it. It returns
// one on success and zero on error.
OPENSSL_EXPORT int X509_VERIFY_PARAM_set1_ip_asc(X509_VERIFY_PARAM *param,
                                                 const char *ipasc);

// X509_PURPOSE_SSL_CLIENT validates TLS client certificates. It checks for the
// id-kp-clientAuth EKU and one of digitalSignature or keyAgreement key usages.
// The TLS library is expected to check for the key usage specific to the
// negotiated TLS parameters.
#define X509_PURPOSE_SSL_CLIENT 1
// X509_PURPOSE_SSL_SERVER validates TLS server certificates. It checks for the
// id-kp-clientAuth EKU and one of digitalSignature, keyAgreement, or
// keyEncipherment key usages. The TLS library is expected to check for the key
// usage specific to the negotiated TLS parameters.
#define X509_PURPOSE_SSL_SERVER 2
// X509_PURPOSE_NS_SSL_SERVER is a legacy mode. It behaves like
// `X509_PURPOSE_SSL_SERVER`, but only accepts the keyEncipherment key usage,
// used by SSL 2.0 and RSA key exchange. Do not use this.
#define X509_PURPOSE_NS_SSL_SERVER 3
// X509_PURPOSE_SMIME_SIGN validates S/MIME signing certificates. It checks for
// the id-kp-emailProtection EKU and one of digitalSignature or nonRepudiation
// key usages.
#define X509_PURPOSE_SMIME_SIGN 4
// X509_PURPOSE_SMIME_ENCRYPT validates S/MIME encryption certificates. It
// checks for the id-kp-emailProtection EKU and keyEncipherment key usage.
#define X509_PURPOSE_SMIME_ENCRYPT 5
// X509_PURPOSE_CRL_SIGN validates indirect CRL signers. It checks for the
// cRLSign key usage. BoringSSL does not support indirect CRLs and does not use
// this mode.
#define X509_PURPOSE_CRL_SIGN 6
// X509_PURPOSE_ANY performs no EKU or key usage checks. Such checks are the
// responsibility of the caller.
#define X509_PURPOSE_ANY 7
// X509_PURPOSE_OCSP_HELPER performs no EKU or key usage checks. It was
// historically used in OpenSSL's OCSP implementation, which left those checks
// to the OCSP implementation itself.
#define X509_PURPOSE_OCSP_HELPER 8
// X509_PURPOSE_TIMESTAMP_SIGN validates Time Stamping Authority (RFC 3161)
// certificates. It checks for the id-kp-timeStamping EKU and one of
// digitalSignature or nonRepudiation key usages. It additionally checks that
// the EKU extension is critical and that no other EKUs or key usages are
// asserted.
#define X509_PURPOSE_TIMESTAMP_SIGN 9

// X509_VERIFY_PARAM_set_purpose configures `param` to validate certificates for
// a specified purpose. It returns one on success and zero if `purpose` is not a
// valid purpose type. `purpose` should be one of the `X509_PURPOSE_*` values.
//
// This option controls checking the extended key usage (EKU) and key usage
// extensions. These extensions specify how a certificate's public key may be
// used and are important to avoid cross-protocol attacks, particularly in PKIs
// that may issue certificates for multiple protocols, or for protocols that use
// keys in multiple ways. If not configured, these security checks are the
// caller's responsibility.
//
// This library applies the EKU checks to all untrusted intermediates. Although
// not defined in RFC 5280, this matches widely-deployed practice. It also does
// not accept anyExtendedKeyUsage.
//
// Many purpose values have a corresponding trust value, which is not configured
// by this function.  See `X509_VERIFY_PARAM_set_trust` for details. Callers
// that wish to configure both should either call both functions, or use
// `X509_STORE_CTX_set_purpose`.
//
// It is currently not possible to configure custom EKU OIDs or key usage bits.
// Contact the BoringSSL maintainers if your application needs to do so. OpenSSL
// had an `X509_PURPOSE_add` API, but it was not thread-safe and relied on
// global mutable state, so we removed it.
//
// TODO(davidben): This function additionally configures checking the legacy
// Netscape certificate type extension. Remove this.
OPENSSL_EXPORT int X509_VERIFY_PARAM_set_purpose(X509_VERIFY_PARAM *param,
                                                 int purpose);

// X509_TRUST_COMPAT evaluates trust using only the self-signed fallback. Trust
// and distrust OIDs are ignored.
#define X509_TRUST_COMPAT 1
// X509_TRUST_SSL_CLIENT evaluates trust with the `NID_client_auth` OID, for
// validating TLS client certificates.
#define X509_TRUST_SSL_CLIENT 2
// X509_TRUST_SSL_SERVER evaluates trust with the `NID_server_auth` OID, for
// validating TLS server certificates.
#define X509_TRUST_SSL_SERVER 3
// X509_TRUST_EMAIL evaluates trust with the `NID_email_protect` OID, for
// validating S/MIME email certificates.
#define X509_TRUST_EMAIL 4
// X509_TRUST_OBJECT_SIGN evaluates trust with the `NID_code_sign` OID, for
// validating code signing certificates.
#define X509_TRUST_OBJECT_SIGN 5
// X509_TRUST_TSA evaluates trust with the `NID_time_stamp` OID, for validating
// Time Stamping Authority (RFC 3161) certificates.
#define X509_TRUST_TSA 8

// X509_VERIFY_PARAM_set_trust configures which certificates from `X509_STORE`
// are trust anchors. It returns one on success and zero if `trust` is not a
// valid trust value. `trust` should be one of the `X509_TRUST_*` constants.
// This function allows applications to vary trust anchors when the same set of
// trusted certificates is used in multiple contexts.
//
// Two properties determine whether a certificate is a trust anchor:
//
// - Whether it is trusted or distrusted for some OID, via auxiliary information
//   configured by `X509_add1_trust_object` or `X509_add1_reject_object`.
//
// - Whether it is "self-signed". That is, whether `X509_get_extension_flags`
//   includes `EXFLAG_SS`. The signature itself is not checked.
//
// When this function is called, `trust` determines the OID to check in the
// first case. If the certificate is not explicitly trusted or distrusted for
// any OID, it is trusted if self-signed instead.
//
// If unset, the default behavior is to check for the `NID_anyExtendedKeyUsage`
// OID. If the certificate is not explicitly trusted or distrusted for this OID,
// it is trusted if self-signed instead. Note this slightly differs from the
// above.
//
// If the `X509_V_FLAG_PARTIAL_CHAIN` is set, every certificate from
// `X509_STORE` is a trust anchor, unless it was explicitly distrusted for the
// OID.
//
// It is currently not possible to configure custom trust OIDs. Contact the
// BoringSSL maintainers if your application needs to do so. OpenSSL had an
// `X509_TRUST_add` API, but it was not thread-safe and relied on global mutable
// state, so we removed it.
OPENSSL_EXPORT int X509_VERIFY_PARAM_set_trust(X509_VERIFY_PARAM *param,
                                               int trust);


// Filesystem-based certificate stores.
//
// An `X509_STORE` may be configured to get its contents from the filesystem.
// This is done by adding `X509_LOOKUP` structures to the `X509_STORE` with
// `X509_STORE_add_lookup` and then configuring the `X509_LOOKUP` with paths.
//
// Most cases can use `X509_STORE_load_locations`, which configures the same
// thing but is simpler to use.

// X509_STORE_load_locations configures `store` to load data from filepaths
// `file` and `dir`. It returns one on success and zero on error. Either of
// `file` or `dir` may be NULL, but at least one must be non-NULL.
//
// If `file` is non-NULL, it loads CRLs and trusted certificates in PEM format
// from the file at `file`, and them to `store`, as in `X509_load_cert_crl_file`
// with `X509_FILETYPE_PEM`.
//
// If `dir` is non-NULL, it configures `store` to load CRLs and trusted
// certificates from the directory at `dir` in PEM format, as in
// `X509_LOOKUP_add_dir` with `X509_FILETYPE_PEM`.
OPENSSL_EXPORT int X509_STORE_load_locations(X509_STORE *store,
                                             const char *file, const char *dir);

// X509_STORE_add_lookup returns an `X509_LOOKUP` associated with `store` with
// type `method`, or NULL on error. The result is owned by `store`, so callers
// are not expected to free it. This may be used with `X509_LOOKUP_add_dir` or
// `X509_LOOKUP_load_file`, depending on `method`, to configure `store`.
//
// A single `X509_LOOKUP` may be configured with multiple paths, and an
// `X509_STORE` only contains one `X509_LOOKUP` of each type, so there is no
// need to call this function multiple times for a single type. Calling it
// multiple times will return the previous `X509_LOOKUP` of that type.
OPENSSL_EXPORT X509_LOOKUP *X509_STORE_add_lookup(
    X509_STORE *store, const X509_LOOKUP_METHOD *method);

// X509_LOOKUP_hash_dir creates `X509_LOOKUP`s that may be used with
// `X509_LOOKUP_add_dir`.
OPENSSL_EXPORT const X509_LOOKUP_METHOD *X509_LOOKUP_hash_dir(void);

// X509_LOOKUP_file creates `X509_LOOKUP`s that may be used with
// `X509_LOOKUP_load_file`.
//
// Although this is modeled as an `X509_LOOKUP`, this function is redundant. It
// has the same effect as loading a certificate or CRL from the filesystem, in
// the caller's desired format, and then adding it with `X509_STORE_add_cert`
// and `X509_STORE_add_crl`.
OPENSSL_EXPORT const X509_LOOKUP_METHOD *X509_LOOKUP_file(void);

// The following constants are used to specify the format of files in an
// `X509_LOOKUP`.
#define X509_FILETYPE_PEM 1
#define X509_FILETYPE_ASN1 2
#define X509_FILETYPE_DEFAULT 3

// X509_LOOKUP_load_file calls `X509_load_cert_crl_file`. `lookup` must have
// been constructed with `X509_LOOKUP_file`.
//
// If `type` is `X509_FILETYPE_DEFAULT`, it ignores `file` and instead uses some
// default system path with `X509_FILETYPE_PEM`. See also
// `X509_STORE_set_default_paths`.
OPENSSL_EXPORT int X509_LOOKUP_load_file(X509_LOOKUP *lookup, const char *file,
                                         int type);

// X509_LOOKUP_add_dir configures `lookup` to load CRLs and trusted certificates
// from the directories in `path`. It returns one on success and zero on error.
// `lookup` must have been constructed with `X509_LOOKUP_hash_dir`.
//
// WARNING: `path` is interpreted as a colon-separated (semicolon-separated on
// Windows) list of paths. It is not possible to configure a path containing the
// separator character. https://crbug.com/boringssl/691 tracks removing this
// behavior.
//
// `type` should be one of the `X509_FILETYPE_*` constants and determines the
// format of the files. If `type` is `X509_FILETYPE_DEFAULT`, `path` is ignored
// and some default system path is used with `X509_FILETYPE_PEM`. See also
// `X509_STORE_set_default_paths`.
//
// Trusted certificates should be named HASH.N and CRLs should be
// named HASH.rN. HASH is `X509_NAME_hash` of the certificate subject and CRL
// issuer, respectively, in hexadecimal. N is in decimal and counts hash
// collisions consecutively, starting from zero. For example, "002c0b4f.0" and
// "002c0b4f.r0".
//
// WARNING: Objects from `path` are loaded on demand, but cached in memory on
// the `X509_STORE`. If a CA is removed from the directory, existing
// `X509_STORE`s will continue to trust it. Cache entries are not evicted for
// the lifetime of the `X509_STORE`.
//
// WARNING: This mechanism is also not well-suited for CRL updates.
// `X509_STORE`s rely on this cache and never load the same CRL file twice. CRL
// updates must use a new file, with an incremented suffix, to be reflected in
// existing `X509_STORE`s. However, this means each CRL update will use
// additional storage and memory. Instead, configure inputs that vary per
// verification, such as CRLs, on each `X509_STORE_CTX` separately, using
// functions like `X509_STORE_CTX_set0_crl`.
OPENSSL_EXPORT int X509_LOOKUP_add_dir(X509_LOOKUP *lookup, const char *path,
                                       int type);

// X509_L_* are commands for `X509_LOOKUP_ctrl`.
#define X509_L_FILE_LOAD 1
#define X509_L_ADD_DIR 2

// X509_LOOKUP_ctrl implements commands on `lookup`. `cmd` specifies the
// command. The other arguments specify the operation in a command-specific way.
// Use `X509_LOOKUP_load_file` or `X509_LOOKUP_add_dir` instead.
OPENSSL_EXPORT int X509_LOOKUP_ctrl(X509_LOOKUP *lookup, int cmd,
                                    const char *argc, long argl, char **ret);

// X509_load_cert_file loads trusted certificates from `file` and adds them to
// `lookup`'s `X509_STORE`. It returns one on success and zero on error.
//
// If `type` is `X509_FILETYPE_ASN1`, it loads a single DER-encoded certificate.
// If `type` is `X509_FILETYPE_PEM`, it loads a sequence of PEM-encoded
// certificates. `type` may not be `X509_FILETYPE_DEFAULT`.
OPENSSL_EXPORT int X509_load_cert_file(X509_LOOKUP *lookup, const char *file,
                                       int type);

// X509_load_crl_file loads CRLs from `file` and add them it to `lookup`'s
// `X509_STORE`. It returns one on success and zero on error.
//
// If `type` is `X509_FILETYPE_ASN1`, it loads a single DER-encoded CRL. If
// `type` is `X509_FILETYPE_PEM`, it loads a sequence of PEM-encoded CRLs.
// `type` may not be `X509_FILETYPE_DEFAULT`.
OPENSSL_EXPORT int X509_load_crl_file(X509_LOOKUP *lookup, const char *file,
                                      int type);

// X509_load_cert_crl_file loads CRLs and trusted certificates from `file` and
// adds them to `lookup`'s `X509_STORE`. It returns one on success and zero on
// error.
//
// If `type` is `X509_FILETYPE_ASN1`, it loads a single DER-encoded certificate.
// This function cannot be used to load a DER-encoded CRL. If `type` is
// `X509_FILETYPE_PEM`, it loads a sequence of PEM-encoded certificates and
// CRLs. `type` may not be `X509_FILETYPE_DEFAULT`.
OPENSSL_EXPORT int X509_load_cert_crl_file(X509_LOOKUP *lookup,
                                           const char *file, int type);

// X509_NAME_hash returns a hash of `name`, or zero on error. This is the new
// hash used by `X509_LOOKUP_add_dir`.
//
// This hash is specific to the `X509_LOOKUP_add_dir` filesystem format and is
// not suitable for general-purpose X.509 name processing. It is very short, so
// there will be hash collisions. It also depends on an OpenSSL-specific
// canonicalization process.
OPENSSL_EXPORT uint32_t X509_NAME_hash(const X509_NAME *name);

// X509_NAME_hash_old returns a hash of `name`, or zero on error. This is the
// legacy hash used by `X509_LOOKUP_add_dir`, which is still supported for
// compatibility.
//
// This hash is specific to the `X509_LOOKUP_add_dir` filesystem format and is
// not suitable for general-purpose X.509 name processing. It is very short, so
// there will be hash collisions.
OPENSSL_EXPORT uint32_t X509_NAME_hash_old(const X509_NAME *name);

// X509_STORE_set_default_paths configures `store` to read from some "default"
// filesystem paths. It returns one on success and zero on error. The filesystem
// paths are determined by a combination of hardcoded paths and the SSL_CERT_DIR
// and SSL_CERT_FILE environment variables.
//
// Using this function is not recommended. In OpenSSL, these defaults are
// determined by OpenSSL's install prefix. There is no corresponding concept for
// BoringSSL. Future versions of BoringSSL may change or remove this
// functionality.
OPENSSL_EXPORT int X509_STORE_set_default_paths(X509_STORE *store);

// The following functions return filesystem paths used to determine the above
// "default" paths, when the corresponding environment variables are not set.
//
// Using these functions is not recommended. In OpenSSL, these defaults are
// determined by OpenSSL's install prefix. There is no corresponding concept for
// BoringSSL. Future versions of BoringSSL may change or remove this
// functionality.
OPENSSL_EXPORT const char *X509_get_default_cert_area(void);
OPENSSL_EXPORT const char *X509_get_default_cert_dir(void);
OPENSSL_EXPORT const char *X509_get_default_cert_file(void);
OPENSSL_EXPORT const char *X509_get_default_private_dir(void);

// X509_get_default_cert_dir_env returns "SSL_CERT_DIR", an environment variable
// used to determine the above "default" paths.
OPENSSL_EXPORT const char *X509_get_default_cert_dir_env(void);

// X509_get_default_cert_file_env returns "SSL_CERT_FILE", an environment
// variable used to determine the above "default" paths.
OPENSSL_EXPORT const char *X509_get_default_cert_file_env(void);


// SignedPublicKeyAndChallenge structures.
//
// The SignedPublicKeyAndChallenge (SPKAC) is a legacy structure to request
// certificates, primarily in the legacy <keygen> HTML tag. An SPKAC structure
// is represented by a `NETSCAPE_SPKI` structure.
//
// The structure is described in
// https://developer.mozilla.org/en-US/docs/Web/HTML/Element/keygen

// A Netscape_spki_st, or `NETSCAPE_SPKI`, represents a
// SignedPublicKeyAndChallenge structure. Although this structure contains a
// `spkac` field of type `NETSCAPE_SPKAC`, these are misnamed. The SPKAC is the
// entire structure, not the signed portion.
struct Netscape_spki_st {
  NETSCAPE_SPKAC *spkac;
  X509_ALGOR *sig_algor;
  ASN1_BIT_STRING *signature;
} /* NETSCAPE_SPKI */;

// NETSCAPE_SPKI_new returns a newly-allocated, empty `NETSCAPE_SPKI` object, or
// NULL on error.
OPENSSL_EXPORT NETSCAPE_SPKI *NETSCAPE_SPKI_new(void);

// NETSCAPE_SPKI_free releases memory associated with `spki`.
OPENSSL_EXPORT void NETSCAPE_SPKI_free(NETSCAPE_SPKI *spki);

// d2i_NETSCAPE_SPKI parses up to `len` bytes from `*inp` as a DER-encoded
// SignedPublicKeyAndChallenge structure, as described in `d2i_SAMPLE`.
OPENSSL_EXPORT NETSCAPE_SPKI *d2i_NETSCAPE_SPKI(NETSCAPE_SPKI **out,
                                                const uint8_t **inp, long len);

// i2d_NETSCAPE_SPKI marshals `spki` as a DER-encoded
// SignedPublicKeyAndChallenge structure, as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_NETSCAPE_SPKI(const NETSCAPE_SPKI *spki, uint8_t **outp);

// NETSCAPE_SPKI_verify checks that `spki` has a valid signature by `pkey`. It
// returns one if the signature is valid and zero otherwise.
OPENSSL_EXPORT int NETSCAPE_SPKI_verify(NETSCAPE_SPKI *spki, EVP_PKEY *pkey);

// NETSCAPE_SPKI_b64_decode decodes `len` bytes from `str` as a base64-encoded
// SignedPublicKeyAndChallenge structure. It returns a newly-allocated
// `NETSCAPE_SPKI` structure with the result, or NULL on error. If `len` is 0 or
// negative, the length is calculated with `strlen` and `str` must be a
// NUL-terminated C string.
OPENSSL_EXPORT NETSCAPE_SPKI *NETSCAPE_SPKI_b64_decode(const char *str,
                                                       ossl_ssize_t len);

// NETSCAPE_SPKI_b64_encode encodes `spki` as a base64-encoded
// SignedPublicKeyAndChallenge structure. It returns a newly-allocated
// NUL-terminated C string with the result, or NULL on error. The caller must
// release the memory with `OPENSSL_free` when done.
OPENSSL_EXPORT char *NETSCAPE_SPKI_b64_encode(NETSCAPE_SPKI *spki);

// NETSCAPE_SPKI_get_pubkey decodes and returns the public key in `spki` as an
// `EVP_PKEY`, or NULL on error. The caller takes ownership of the resulting
// pointer and must call `EVP_PKEY_free` when done.
OPENSSL_EXPORT EVP_PKEY *NETSCAPE_SPKI_get_pubkey(const NETSCAPE_SPKI *spki);

// NETSCAPE_SPKI_set_pubkey sets `spki`'s public key to `pkey`. It returns one
// on success or zero on error. This function does not take ownership of `pkey`,
// so the caller may continue to manage its lifetime independently of `spki`.
OPENSSL_EXPORT int NETSCAPE_SPKI_set_pubkey(NETSCAPE_SPKI *spki,
                                            EVP_PKEY *pkey);

// NETSCAPE_SPKI_sign signs `spki` with `pkey` and replaces the signature
// algorithm and signature fields. It returns the length of the signature on
// success and zero on error. This function uses digest algorithm `md`, or
// `pkey`'s default if NULL. Other signing parameters use `pkey`'s defaults.
OPENSSL_EXPORT int NETSCAPE_SPKI_sign(NETSCAPE_SPKI *spki, EVP_PKEY *pkey,
                                      const EVP_MD *md);

// A Netscape_spkac_st, or `NETSCAPE_SPKAC`, represents a PublicKeyAndChallenge
// structure. This type is misnamed. The full SPKAC includes the signature,
// which is represented with the `NETSCAPE_SPKI` type.
struct Netscape_spkac_st {
  X509_PUBKEY *pubkey;
  ASN1_IA5STRING *challenge;
} /* NETSCAPE_SPKAC */;

// NETSCAPE_SPKAC_new returns a newly-allocated, empty `NETSCAPE_SPKAC` object,
// or NULL on error.
OPENSSL_EXPORT NETSCAPE_SPKAC *NETSCAPE_SPKAC_new(void);

// NETSCAPE_SPKAC_free releases memory associated with `spkac`.
OPENSSL_EXPORT void NETSCAPE_SPKAC_free(NETSCAPE_SPKAC *spkac);

// d2i_NETSCAPE_SPKAC parses up to `len` bytes from `*inp` as a DER-encoded
// PublicKeyAndChallenge structure, as described in `d2i_SAMPLE`.
OPENSSL_EXPORT NETSCAPE_SPKAC *d2i_NETSCAPE_SPKAC(NETSCAPE_SPKAC **out,
                                                  const uint8_t **inp,
                                                  long len);

// i2d_NETSCAPE_SPKAC marshals `spkac` as a DER-encoded PublicKeyAndChallenge
// structure, as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_NETSCAPE_SPKAC(const NETSCAPE_SPKAC *spkac,
                                      uint8_t **outp);


// RSASSA-PSS Parameters.
//
// In X.509, RSASSA-PSS signatures and keys use a complex parameter structure,
// defined in RFC 4055. The following functions are provided for compatibility
// with some OpenSSL APIs relating to this. Use of RSASSA-PSS in X.509 is
// discouraged. The parameters structure is very complex, and it takes more
// bytes to merely encode parameters than an entire P-256 ECDSA signature.

// An rsa_pss_params_st, aka `RSA_PSS_PARAMS`, represents a parsed
// RSASSA-PSS-params structure, as defined in (RFC 4055).
struct rsa_pss_params_st {
  X509_ALGOR *hashAlgorithm;
  X509_ALGOR *maskGenAlgorithm;
  ASN1_INTEGER *saltLength;
  ASN1_INTEGER *trailerField;
  // OpenSSL caches the MGF hash on `RSA_PSS_PARAMS` in some cases. None of the
  // cases apply to BoringSSL, so this is always NULL, but Node expects the
  // field to be present.
  X509_ALGOR *maskHash;
} /* RSA_PSS_PARAMS */;

// RSA_PSS_PARAMS is an `ASN1_ITEM` whose ASN.1 type is RSASSA-PSS-params (RFC
// 4055) and C type is `RSA_PSS_PARAMS*`.
DECLARE_ASN1_ITEM(RSA_PSS_PARAMS)

// RSA_PSS_PARAMS_new returns a new, empty `RSA_PSS_PARAMS`, or NULL on error.
OPENSSL_EXPORT RSA_PSS_PARAMS *RSA_PSS_PARAMS_new(void);

// RSA_PSS_PARAMS_free releases memory associated with `params`.
OPENSSL_EXPORT void RSA_PSS_PARAMS_free(RSA_PSS_PARAMS *params);

// d2i_RSA_PSS_PARAMS parses up to `len` bytes from `*inp` as a DER-encoded
// RSASSA-PSS-params (RFC 4055), as described in `d2i_SAMPLE`.
OPENSSL_EXPORT RSA_PSS_PARAMS *d2i_RSA_PSS_PARAMS(RSA_PSS_PARAMS **out,
                                                  const uint8_t **inp,
                                                  long len);

// i2d_RSA_PSS_PARAMS marshals `in` as a DER-encoded RSASSA-PSS-params (RFC
// 4055), as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_RSA_PSS_PARAMS(const RSA_PSS_PARAMS *in, uint8_t **outp);


// PKCS#8 private keys.
//
// The `PKCS8_PRIV_KEY_INFO` type represents a PKCS#8 PrivateKeyInfo (RFC 5208)
// structure. This is analogous to SubjectPublicKeyInfo and uses the same
// AlgorithmIdentifiers, but carries private keys and is not part of X.509
// itself.
//
// TODO(davidben): Do these functions really belong in this header?

// PKCS8_PRIV_KEY_INFO_new returns a newly-allocated, empty
// `PKCS8_PRIV_KEY_INFO` object, or NULL on error.
OPENSSL_EXPORT PKCS8_PRIV_KEY_INFO *PKCS8_PRIV_KEY_INFO_new(void);

// PKCS8_PRIV_KEY_INFO_free releases memory associated with `key`.
OPENSSL_EXPORT void PKCS8_PRIV_KEY_INFO_free(PKCS8_PRIV_KEY_INFO *key);

// d2i_PKCS8_PRIV_KEY_INFO parses up to `len` bytes from `*inp` as a DER-encoded
// PrivateKeyInfo, as described in `d2i_SAMPLE`.
OPENSSL_EXPORT PKCS8_PRIV_KEY_INFO *d2i_PKCS8_PRIV_KEY_INFO(
    PKCS8_PRIV_KEY_INFO **out, const uint8_t **inp, long len);

// i2d_PKCS8_PRIV_KEY_INFO marshals `key` as a DER-encoded PrivateKeyInfo, as
// described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_PKCS8_PRIV_KEY_INFO(const PKCS8_PRIV_KEY_INFO *key,
                                           uint8_t **outp);

// EVP_PKCS82PKEY returns `p8` as a newly-allocated `EVP_PKEY`, or NULL if the
// key was unsupported or could not be decoded. The caller must release the
// result with `EVP_PKEY_free` when done.
//
// Use `EVP_parse_private_key` instead.
OPENSSL_EXPORT EVP_PKEY *EVP_PKCS82PKEY(const PKCS8_PRIV_KEY_INFO *p8);

// EVP_PKEY2PKCS8 encodes `pkey` as a PKCS#8 PrivateKeyInfo (RFC 5208),
// represented as a newly-allocated `PKCS8_PRIV_KEY_INFO`, or NULL on error. The
// caller must release the result with `PKCS8_PRIV_KEY_INFO_free` when done.
//
// Use `EVP_marshal_private_key` instead.
OPENSSL_EXPORT PKCS8_PRIV_KEY_INFO *EVP_PKEY2PKCS8(const EVP_PKEY *pkey);


// Algorithm and octet string pairs.
//
// The `X509_SIG` type represents an ASN.1 SEQUENCE type of an
// AlgorithmIdentifier and an OCTET STRING. Although named `X509_SIG`, there is
// no type in X.509 which matches this format. The two common types which do are
// DigestInfo (RFC 2315 and RFC 8017), and EncryptedPrivateKeyInfo (RFC 5208).

// X509_SIG_new returns a newly-allocated, empty `X509_SIG` object, or NULL on
// error.
OPENSSL_EXPORT X509_SIG *X509_SIG_new(void);

// X509_SIG_free releases memory associated with `key`.
OPENSSL_EXPORT void X509_SIG_free(X509_SIG *key);

// d2i_X509_SIG parses up to `len` bytes from `*inp` as a DER-encoded algorithm
// and octet string pair, as described in `d2i_SAMPLE`.
OPENSSL_EXPORT X509_SIG *d2i_X509_SIG(X509_SIG **out, const uint8_t **inp,
                                      long len);

// i2d_X509_SIG marshals `sig` as a DER-encoded algorithm
// and octet string pair, as described in `i2d_SAMPLE`.
OPENSSL_EXPORT int i2d_X509_SIG(const X509_SIG *sig, uint8_t **outp);

// X509_SIG_get0 sets `*out_alg` and `*out_digest` to non-owning pointers to
// `sig`'s algorithm and digest fields, respectively. Either `out_alg` and
// `out_digest` may be NULL to skip those fields.
OPENSSL_EXPORT void X509_SIG_get0(const X509_SIG *sig,
                                  const X509_ALGOR **out_alg,
                                  const ASN1_OCTET_STRING **out_digest);

// X509_SIG_getm behaves like `X509_SIG_get0` but returns mutable pointers.
OPENSSL_EXPORT void X509_SIG_getm(X509_SIG *sig, X509_ALGOR **out_alg,
                                  ASN1_OCTET_STRING **out_digest);


// Printing functions.
//
// The following functions output human-readable representations of
// X.509-related structures. They should only be used for debugging or logging
// and not parsed programmatically. In many cases, the outputs are ambiguous, so
// attempting to parse them can lead to string injection vulnerabilities.

// The following flags control `X509_print_ex` and `X509_REQ_print_ex`. These
// flags co-exist with `X509V3_EXT_*`, so avoid collisions when adding new ones.

// X509_FLAG_COMPAT disables all flags. It additionally causes names to be
// printed with a 16-byte indent.
#define X509_FLAG_COMPAT 0

// X509_FLAG_NO_HEADER skips a header identifying the type of object printed.
#define X509_FLAG_NO_HEADER 1L

// X509_FLAG_NO_VERSION skips printing the X.509 version number.
#define X509_FLAG_NO_VERSION (1L << 1)

// X509_FLAG_NO_SERIAL skips printing the serial number. It is ignored in
// `X509_REQ_print_fp`.
#define X509_FLAG_NO_SERIAL (1L << 2)

// X509_FLAG_NO_SIGNAME skips printing the signature algorithm in the
// TBSCertificate. It is ignored in `X509_REQ_print_fp`.
#define X509_FLAG_NO_SIGNAME (1L << 3)

// X509_FLAG_NO_ISSUER skips printing the issuer.
#define X509_FLAG_NO_ISSUER (1L << 4)

// X509_FLAG_NO_VALIDITY skips printing the notBefore and notAfter times. It is
// ignored in `X509_REQ_print_fp`.
#define X509_FLAG_NO_VALIDITY (1L << 5)

// X509_FLAG_NO_SUBJECT skips printing the subject.
#define X509_FLAG_NO_SUBJECT (1L << 6)

// X509_FLAG_NO_PUBKEY skips printing the public key.
#define X509_FLAG_NO_PUBKEY (1L << 7)

// X509_FLAG_NO_EXTENSIONS skips printing the extension list. It is ignored in
// `X509_REQ_print_fp`. CSRs instead have attributes, which is controlled by
// `X509_FLAG_NO_ATTRIBUTES`.
#define X509_FLAG_NO_EXTENSIONS (1L << 8)

// X509_FLAG_NO_SIGDUMP skips printing the signature and outer signature
// algorithm.
#define X509_FLAG_NO_SIGDUMP (1L << 9)

// X509_FLAG_NO_AUX skips printing auxiliary properties. (See `d2i_X509_AUX` and
// related functions.)
#define X509_FLAG_NO_AUX (1L << 10)

// X509_FLAG_NO_ATTRIBUTES skips printing CSR attributes. It does nothing for
// certificates and CRLs.
#define X509_FLAG_NO_ATTRIBUTES (1L << 11)

// X509_FLAG_NO_IDS skips printing the issuerUniqueID and subjectUniqueID in a
// certificate. It is ignored in `X509_REQ_print_fp`.
#define X509_FLAG_NO_IDS (1L << 12)

// The following flags control `X509_print_ex`, `X509_REQ_print_ex`,
// `X509V3_EXT_print`, and `X509V3_extensions_print`. These flags coexist with
// `X509_FLAG_*`, so avoid collisions when adding new ones.

// X509V3_EXT_UNKNOWN_MASK is a mask that determines how unknown extensions are
// processed.
#define X509V3_EXT_UNKNOWN_MASK (0xfL << 16)

// X509V3_EXT_DEFAULT causes unknown extensions or syntax errors to return
// failure.
#define X509V3_EXT_DEFAULT 0

// X509V3_EXT_ERROR_UNKNOWN causes unknown extensions or syntax errors to print
// as "<Not Supported>" or "<Parse Error>", respectively.
#define X509V3_EXT_ERROR_UNKNOWN (1L << 16)

// X509V3_EXT_PARSE_UNKNOWN is deprecated and behaves like
// `X509V3_EXT_DUMP_UNKNOWN`.
#define X509V3_EXT_PARSE_UNKNOWN (2L << 16)

// X509V3_EXT_DUMP_UNKNOWN causes unknown extensions to be displayed as a
// hexdump.
#define X509V3_EXT_DUMP_UNKNOWN (3L << 16)

// X509_print_ex writes a human-readable representation of `x` to `bp`. It
// returns one on success and zero on error. `nmflags` is the flags parameter
// for `X509_NAME_print_ex` when printing the subject and issuer. `cflag` should
// be some combination of the `X509_FLAG_*` and `X509V3_EXT_*` constants.
OPENSSL_EXPORT int X509_print_ex(BIO *bp, const X509 *x, unsigned long nmflag,
                                 unsigned long cflag);

// X509_print_ex_fp behaves like `X509_print_ex` but writes to `fp`.
OPENSSL_EXPORT int X509_print_ex_fp(FILE *fp, const X509 *x,
                                    unsigned long nmflag, unsigned long cflag);

// X509_print calls `X509_print_ex` with `XN_FLAG_COMPAT` and `X509_FLAG_COMPAT`
// flags.
OPENSSL_EXPORT int X509_print(BIO *bp, const X509 *x);

// X509_print_fp behaves like `X509_print` but writes to `fp`.
OPENSSL_EXPORT int X509_print_fp(FILE *fp, const X509 *x);

// X509_CRL_print writes a human-readable representation of `x` to `bp`. It
// returns one on success and zero on error.
OPENSSL_EXPORT int X509_CRL_print(BIO *bp, const X509_CRL *x);

// X509_CRL_print_fp behaves like `X509_CRL_print` but writes to `fp`.
OPENSSL_EXPORT int X509_CRL_print_fp(FILE *fp, const X509_CRL *x);

// X509_REQ_print_ex writes a human-readable representation of `x` to `bp`. It
// returns one on success and zero on error. `nmflags` is the flags parameter
// for `X509_NAME_print_ex`, when printing the subject. `cflag` should be some
// combination of the `X509_FLAG_*` and `X509V3_EXT_*` constants.
OPENSSL_EXPORT int X509_REQ_print_ex(BIO *bp, const X509_REQ *x,
                                     unsigned long nmflag, unsigned long cflag);

// X509_REQ_print calls `X509_REQ_print_ex` with `XN_FLAG_COMPAT` and
// `X509_FLAG_COMPAT` flags.
OPENSSL_EXPORT int X509_REQ_print(BIO *bp, const X509_REQ *req);

// X509_REQ_print_fp behaves like `X509_REQ_print` but writes to `fp`.
OPENSSL_EXPORT int X509_REQ_print_fp(FILE *fp, const X509_REQ *req);

// The following flags are control `X509_NAME_print_ex`. They must not collide
// with `ASN1_STRFLGS_*`.
//
// TODO(davidben): This is far, far too many options and most of them are
// useless. Trim this down.

// XN_FLAG_COMPAT prints with `X509_NAME_print`'s format and return value
// convention.
#define XN_FLAG_COMPAT 0ul

// XN_FLAG_SEP_MASK determines the separators to use between attributes.
#define XN_FLAG_SEP_MASK (0xful << 16)

// XN_FLAG_SEP_COMMA_PLUS separates RDNs with "," and attributes within an RDN
// with "+", as in RFC 2253.
#define XN_FLAG_SEP_COMMA_PLUS (1ul << 16)

// XN_FLAG_SEP_CPLUS_SPC behaves like `XN_FLAG_SEP_COMMA_PLUS` but adds spaces
// between the separators.
#define XN_FLAG_SEP_CPLUS_SPC (2ul << 16)

// XN_FLAG_SEP_SPLUS_SPC separates RDNs with "; " and attributes within an RDN
// with " + ".
#define XN_FLAG_SEP_SPLUS_SPC (3ul << 16)

// XN_FLAG_SEP_MULTILINE prints each attribute on one line.
#define XN_FLAG_SEP_MULTILINE (4ul << 16)

// XN_FLAG_DN_REV prints RDNs in reverse, from least significant to most
// significant, as RFC 2253.
#define XN_FLAG_DN_REV (1ul << 20)

// XN_FLAG_FN_MASK determines how attribute types are displayed.
#define XN_FLAG_FN_MASK (0x3ul << 21)

// XN_FLAG_FN_SN uses the attribute type's short name, when available.
#define XN_FLAG_FN_SN 0ul

// XN_FLAG_SPC_EQ wraps the "=" operator with spaces when printing attributes.
#define XN_FLAG_SPC_EQ (1ul << 23)

// XN_FLAG_DUMP_UNKNOWN_FIELDS causes unknown attribute types to be printed in
// hex, as in RFC 2253.
#define XN_FLAG_DUMP_UNKNOWN_FIELDS (1ul << 24)

// XN_FLAG_RFC2253 prints like RFC 2253.
#define XN_FLAG_RFC2253                                             \
  (ASN1_STRFLGS_RFC2253 | XN_FLAG_SEP_COMMA_PLUS | XN_FLAG_DN_REV | \
   XN_FLAG_FN_SN | XN_FLAG_DUMP_UNKNOWN_FIELDS)

// XN_FLAG_ONELINE prints a one-line representation of the name.
#define XN_FLAG_ONELINE                                                    \
  (ASN1_STRFLGS_RFC2253 | ASN1_STRFLGS_ESC_QUOTE | XN_FLAG_SEP_CPLUS_SPC | \
   XN_FLAG_SPC_EQ | XN_FLAG_FN_SN)

// X509_NAME_print_ex writes a human-readable representation of `nm` to `out`.
// Each line of output is indented by `indent` spaces. It returns the number of
// bytes written on success, and -1 on error. If `out` is NULL, it returns the
// number of bytes it would have written but does not write anything. `flags`
// should be some combination of `XN_FLAG_*` and `ASN1_STRFLGS_*` values and
// determines the output. If unsure, use `XN_FLAG_RFC2253`.
//
// If `flags` is `XN_FLAG_COMPAT`, or zero, this function calls
// `X509_NAME_print` instead. In that case, it returns one on success, rather
// than the output length.
OPENSSL_EXPORT int X509_NAME_print_ex(BIO *out, const X509_NAME *nm, int indent,
                                      unsigned long flags);

// X509_NAME_print prints a human-readable representation of `name` to `bp`. It
// returns one on success and zero on error. `obase` is ignored.
//
// This function outputs a legacy format that does not correctly handle string
// encodings and other cases. Prefer `X509_NAME_print_ex` if printing a name for
// debugging purposes.
OPENSSL_EXPORT int X509_NAME_print(BIO *bp, const X509_NAME *name, int obase);

// X509_NAME_oneline writes a human-readable representation to `name` to a
// buffer as a NUL-terminated C string.
//
// If `buf` is NULL, returns a newly-allocated buffer containing the result on
// success, or NULL on error. The buffer must be released with `OPENSSL_free`
// when done.
//
// If `buf` is non-NULL, at most `size` bytes of output are written to `buf`
// instead. `size` includes the trailing NUL. The function then returns `buf` on
// success or NULL on error. If the output does not fit in `size` bytes, the
// output is silently truncated at an attribute boundary.
//
// This function outputs a legacy format that does not correctly handle string
// encodings and other cases. Prefer `X509_NAME_print_ex` if printing a name for
// debugging purposes.
OPENSSL_EXPORT char *X509_NAME_oneline(const X509_NAME *name, char *buf,
                                       int size);

// X509_NAME_print_ex_fp behaves like `X509_NAME_print_ex` but writes to `fp`.
OPENSSL_EXPORT int X509_NAME_print_ex_fp(FILE *fp, const X509_NAME *nm,
                                         int indent, unsigned long flags);

// X509_signature_dump writes a human-readable representation of `sig` to `bio`,
// indented with `indent` spaces. It returns one on success and zero on error.
OPENSSL_EXPORT int X509_signature_dump(BIO *bio, const ASN1_STRING *sig,
                                       int indent);

// X509_signature_print writes a human-readable representation of `alg` and
// `sig` to `bio`. It returns one on success and zero on error.
OPENSSL_EXPORT int X509_signature_print(BIO *bio, const X509_ALGOR *alg,
                                        const ASN1_STRING *sig);

// X509V3_EXT_print prints a human-readable representation of `ext` to out. It
// returns one on success and zero on error. The output is indented by `indent`
// spaces. `flag` is one of the `X509V3_EXT_*` constants and controls printing
// of unknown extensions and syntax errors.
//
// WARNING: Although some applications programmatically parse the output of this
// function to process X.509 extensions, this is not safe. In many cases, the
// outputs are ambiguous to attempting to parse them can lead to string
// injection vulnerabilities. These functions should only be used for debugging
// or logging.
OPENSSL_EXPORT int X509V3_EXT_print(BIO *out, const X509_EXTENSION *ext,
                                    unsigned long flag, int indent);

// X509V3_EXT_print_fp behaves like `X509V3_EXT_print` but writes to a `FILE`
// instead of a `BIO`.
OPENSSL_EXPORT int X509V3_EXT_print_fp(FILE *out, const X509_EXTENSION *ext,
                                       int flag, int indent);

// X509V3_extensions_print prints `title`, followed by a human-readable
// representation of `exts` to `out`. It returns one on success and zero on
// error. The output is indented by `indent` spaces. `flag` is one of the
// `X509V3_EXT_*` constants and controls printing of unknown extensions and
// syntax errors.
OPENSSL_EXPORT int X509V3_extensions_print(BIO *out, const char *title,
                                           const STACK_OF(X509_EXTENSION) *exts,
                                           unsigned long flag, int indent);

// GENERAL_NAME_print prints a human-readable representation of `gen` to `out`.
// It returns one on success and zero on error.
//
// TODO(davidben): Actually, it just returns one and doesn't check for I/O or
// allocation errors. But it should return zero on error.
OPENSSL_EXPORT int GENERAL_NAME_print(BIO *out, const GENERAL_NAME *gen);


// Convenience functions.

// X509_pubkey_digest hashes the contents of the BIT STRING in `x509`'s
// subjectPublicKeyInfo field with `md` and writes the result to `out`.
// `EVP_MD_CTX_size` bytes are written, which is at most `EVP_MAX_MD_SIZE`. If
// `out_len` is not NULL, `*out_len` is set to the number of bytes written. This
// function returns one on success and zero on error.
//
// This hash omits the BIT STRING tag, length, and number of unused bits. It
// also omits the AlgorithmIdentifier which describes the key type. It
// corresponds to the OCSP KeyHash definition and is not suitable for other
// purposes.
OPENSSL_EXPORT int X509_pubkey_digest(const X509 *x509, const EVP_MD *md,
                                      uint8_t *out, unsigned *out_len);

// X509_digest hashes `x509`'s DER encoding with `md` and writes the result to
// `out`. `EVP_MD_CTX_size` bytes are written, which is at most
// `EVP_MAX_MD_SIZE`. If `out_len` is not NULL, `*out_len` is set to the number
// of bytes written. This function returns one on success and zero on error.
// Note this digest covers the entire certificate, not just the signed portion.
OPENSSL_EXPORT int X509_digest(const X509 *x509, const EVP_MD *md, uint8_t *out,
                               unsigned *out_len);

// X509_CRL_digest hashes `crl`'s DER encoding with `md` and writes the result
// to `out`. `EVP_MD_CTX_size` bytes are written, which is at most
// `EVP_MAX_MD_SIZE`. If `out_len` is not NULL, `*out_len` is set to the number
// of bytes written. This function returns one on success and zero on error.
// Note this digest covers the entire CRL, not just the signed portion.
OPENSSL_EXPORT int X509_CRL_digest(const X509_CRL *crl, const EVP_MD *md,
                                   uint8_t *out, unsigned *out_len);

// X509_REQ_digest hashes `req`'s DER encoding with `md` and writes the result
// to `out`. `EVP_MD_CTX_size` bytes are written, which is at most
// `EVP_MAX_MD_SIZE`. If `out_len` is not NULL, `*out_len` is set to the number
// of bytes written. This function returns one on success and zero on error.
// Note this digest covers the entire certificate request, not just the signed
// portion.
OPENSSL_EXPORT int X509_REQ_digest(const X509_REQ *req, const EVP_MD *md,
                                   uint8_t *out, unsigned *out_len);

// X509_NAME_digest hashes `name`'s DER encoding with `md` and writes the result
// to `out`. `EVP_MD_CTX_size` bytes are written, which is at most
// `EVP_MAX_MD_SIZE`. If `out_len` is not NULL, `*out_len` is set to the number
// of bytes written. This function returns one on success and zero on error.
OPENSSL_EXPORT int X509_NAME_digest(const X509_NAME *name, const EVP_MD *md,
                                    uint8_t *out, unsigned *out_len);

// The following functions behave like the corresponding unsuffixed `d2i_*`
// functions, but read the result from `bp` instead. Callers using these
// functions with memory `BIO`s to parse structures already in memory should use
// `d2i_*` instead.
OPENSSL_EXPORT X509 *d2i_X509_bio(BIO *bp, X509 **x509);
OPENSSL_EXPORT X509_CRL *d2i_X509_CRL_bio(BIO *bp, X509_CRL **crl);
OPENSSL_EXPORT X509_REQ *d2i_X509_REQ_bio(BIO *bp, X509_REQ **req);
OPENSSL_EXPORT RSA *d2i_RSAPrivateKey_bio(BIO *bp, RSA **rsa);
OPENSSL_EXPORT RSA *d2i_RSAPublicKey_bio(BIO *bp, RSA **rsa);
OPENSSL_EXPORT RSA *d2i_RSA_PUBKEY_bio(BIO *bp, RSA **rsa);
OPENSSL_EXPORT DSA *d2i_DSA_PUBKEY_bio(BIO *bp, DSA **dsa);
OPENSSL_EXPORT DSA *d2i_DSAPrivateKey_bio(BIO *bp, DSA **dsa);
OPENSSL_EXPORT EC_KEY *d2i_EC_PUBKEY_bio(BIO *bp, EC_KEY **eckey);
OPENSSL_EXPORT EC_KEY *d2i_ECPrivateKey_bio(BIO *bp, EC_KEY **eckey);
OPENSSL_EXPORT X509_SIG *d2i_PKCS8_bio(BIO *bp, X509_SIG **p8);
OPENSSL_EXPORT PKCS8_PRIV_KEY_INFO *d2i_PKCS8_PRIV_KEY_INFO_bio(
    BIO *bp, PKCS8_PRIV_KEY_INFO **p8inf);
OPENSSL_EXPORT EVP_PKEY *d2i_PUBKEY_bio(BIO *bp, EVP_PKEY **a);
OPENSSL_EXPORT DH *d2i_DHparams_bio(BIO *bp, DH **dh);

// d2i_PrivateKey_bio behaves like `d2i_AutoPrivateKey`, but reads from `bp`
// instead.
OPENSSL_EXPORT EVP_PKEY *d2i_PrivateKey_bio(BIO *bp, EVP_PKEY **a);

// The following functions behave like the corresponding unsuffixed `i2d_*`
// functions, but write the result to `bp`. They return one on success and zero
// on error. Callers using them with memory `BIO`s to encode structures to
// memory should use `i2d_*` directly instead.
OPENSSL_EXPORT int i2d_X509_bio(BIO *bp, const X509 *x509);
OPENSSL_EXPORT int i2d_X509_CRL_bio(BIO *bp, const X509_CRL *crl);
OPENSSL_EXPORT int i2d_X509_REQ_bio(BIO *bp, const X509_REQ *req);
OPENSSL_EXPORT int i2d_RSAPrivateKey_bio(BIO *bp, const RSA *rsa);
OPENSSL_EXPORT int i2d_RSAPublicKey_bio(BIO *bp, const RSA *rsa);
OPENSSL_EXPORT int i2d_RSA_PUBKEY_bio(BIO *bp, const RSA *rsa);
OPENSSL_EXPORT int i2d_DSA_PUBKEY_bio(BIO *bp, const DSA *dsa);
OPENSSL_EXPORT int i2d_DSAPrivateKey_bio(BIO *bp, const DSA *dsa);
OPENSSL_EXPORT int i2d_EC_PUBKEY_bio(BIO *bp, const EC_KEY *eckey);
OPENSSL_EXPORT int i2d_ECPrivateKey_bio(BIO *bp, const EC_KEY *eckey);
OPENSSL_EXPORT int i2d_PKCS8_bio(BIO *bp, const X509_SIG *p8);
OPENSSL_EXPORT int i2d_PKCS8_PRIV_KEY_INFO_bio(
    BIO *bp, const PKCS8_PRIV_KEY_INFO *p8inf);
OPENSSL_EXPORT int i2d_PrivateKey_bio(BIO *bp, const EVP_PKEY *pkey);
OPENSSL_EXPORT int i2d_PUBKEY_bio(BIO *bp, const EVP_PKEY *pkey);
OPENSSL_EXPORT int i2d_DHparams_bio(BIO *bp, const DH *dh);

// i2d_PKCS8PrivateKeyInfo_bio encodes `key` as a PKCS#8 PrivateKeyInfo
// structure (see `EVP_marshal_private_key`) and writes the result to `bp`. It
// returns one on success and zero on error.
OPENSSL_EXPORT int i2d_PKCS8PrivateKeyInfo_bio(BIO *bp, const EVP_PKEY *key);

// The following functions behave like the corresponding `d2i_*_bio` functions,
// but read from `fp` instead.
OPENSSL_EXPORT X509 *d2i_X509_fp(FILE *fp, X509 **x509);
OPENSSL_EXPORT X509_CRL *d2i_X509_CRL_fp(FILE *fp, X509_CRL **crl);
OPENSSL_EXPORT X509_REQ *d2i_X509_REQ_fp(FILE *fp, X509_REQ **req);
OPENSSL_EXPORT RSA *d2i_RSAPrivateKey_fp(FILE *fp, RSA **rsa);
OPENSSL_EXPORT RSA *d2i_RSAPublicKey_fp(FILE *fp, RSA **rsa);
OPENSSL_EXPORT RSA *d2i_RSA_PUBKEY_fp(FILE *fp, RSA **rsa);
OPENSSL_EXPORT DSA *d2i_DSA_PUBKEY_fp(FILE *fp, DSA **dsa);
OPENSSL_EXPORT DSA *d2i_DSAPrivateKey_fp(FILE *fp, DSA **dsa);
OPENSSL_EXPORT EC_KEY *d2i_EC_PUBKEY_fp(FILE *fp, EC_KEY **eckey);
OPENSSL_EXPORT EC_KEY *d2i_ECPrivateKey_fp(FILE *fp, EC_KEY **eckey);
OPENSSL_EXPORT X509_SIG *d2i_PKCS8_fp(FILE *fp, X509_SIG **p8);
OPENSSL_EXPORT PKCS8_PRIV_KEY_INFO *d2i_PKCS8_PRIV_KEY_INFO_fp(
    FILE *fp, PKCS8_PRIV_KEY_INFO **p8inf);
OPENSSL_EXPORT EVP_PKEY *d2i_PrivateKey_fp(FILE *fp, EVP_PKEY **a);
OPENSSL_EXPORT EVP_PKEY *d2i_PUBKEY_fp(FILE *fp, EVP_PKEY **a);

// The following functions behave like the corresponding `i2d_*_bio` functions,
// but write to `fp` instead.
OPENSSL_EXPORT int i2d_X509_fp(FILE *fp, const X509 *x509);
OPENSSL_EXPORT int i2d_X509_CRL_fp(FILE *fp, const X509_CRL *crl);
OPENSSL_EXPORT int i2d_X509_REQ_fp(FILE *fp, const X509_REQ *req);
OPENSSL_EXPORT int i2d_RSAPrivateKey_fp(FILE *fp, const RSA *rsa);
OPENSSL_EXPORT int i2d_RSAPublicKey_fp(FILE *fp, const RSA *rsa);
OPENSSL_EXPORT int i2d_RSA_PUBKEY_fp(FILE *fp, const RSA *rsa);
OPENSSL_EXPORT int i2d_DSA_PUBKEY_fp(FILE *fp, const DSA *dsa);
OPENSSL_EXPORT int i2d_DSAPrivateKey_fp(FILE *fp, const DSA *dsa);
OPENSSL_EXPORT int i2d_EC_PUBKEY_fp(FILE *fp, const EC_KEY *eckey);
OPENSSL_EXPORT int i2d_ECPrivateKey_fp(FILE *fp, const EC_KEY *eckey);
OPENSSL_EXPORT int i2d_PKCS8_fp(FILE *fp, const X509_SIG *p8);
OPENSSL_EXPORT int i2d_PKCS8_PRIV_KEY_INFO_fp(FILE *fp,
                                              const PKCS8_PRIV_KEY_INFO *p8inf);
OPENSSL_EXPORT int i2d_PKCS8PrivateKeyInfo_fp(FILE *fp, const EVP_PKEY *key);
OPENSSL_EXPORT int i2d_PrivateKey_fp(FILE *fp, const EVP_PKEY *pkey);
OPENSSL_EXPORT int i2d_PUBKEY_fp(FILE *fp, const EVP_PKEY *pkey);

// X509_find_by_issuer_and_serial returns the first `X509` in `sk` whose issuer
// and serial are `name` and `serial`, respectively. If no match is found, it
// returns NULL.
OPENSSL_EXPORT X509 *X509_find_by_issuer_and_serial(const STACK_OF(X509) *sk,
                                                    const X509_NAME *name,
                                                    const ASN1_INTEGER *serial);

// X509_find_by_subject returns the first `X509` in `sk` whose subject is
// `name`. If no match is found, it returns NULL.
OPENSSL_EXPORT X509 *X509_find_by_subject(const STACK_OF(X509) *sk,
                                          const X509_NAME *name);

// X509_cmp_time compares `s` against `*t`. On success, it returns a negative
// number if `s` <= `*t` and a positive number if `s` > `*t`. On error, it
// returns zero. If `t` is NULL, it uses the current time instead of `*t`.
//
// WARNING: Unlike most comparison functions, this function returns zero on
// error, not equality.
OPENSSL_EXPORT int X509_cmp_time(const ASN1_TIME *s, const time_t *t);

// X509_cmp_time_posix compares `s` against `t`. On success, it returns a
// negative number if `s` <= `t` and a positive number if `s` > `t`. On error,
// it returns zero.
//
// WARNING: Unlike most comparison functions, this function returns zero on
// error, not equality.
OPENSSL_EXPORT int X509_cmp_time_posix(const ASN1_TIME *s, int64_t t);

// X509_cmp_current_time behaves like `X509_cmp_time` but compares `s` against
// the current time.
OPENSSL_EXPORT int X509_cmp_current_time(const ASN1_TIME *s);

// X509_time_adj calls `X509_time_adj_ex` with `offset_day` equal to zero.
OPENSSL_EXPORT ASN1_TIME *X509_time_adj(ASN1_TIME *s, long offset_sec,
                                        const time_t *t);

// X509_time_adj_ex behaves like `ASN1_TIME_adj`, but adds an offset to `*t`. If
// `t` is NULL, it uses the current time instead of `*t`.
OPENSSL_EXPORT ASN1_TIME *X509_time_adj_ex(ASN1_TIME *s, int offset_day,
                                           long offset_sec, const time_t *t);

// X509_gmtime_adj behaves like `X509_time_adj_ex` but adds `offset_sec` to the
// current time.
OPENSSL_EXPORT ASN1_TIME *X509_gmtime_adj(ASN1_TIME *s, long offset_sec);

// X509_issuer_name_cmp behaves like `X509_NAME_cmp`, but compares `a` and `b`'s
// issuer names.
OPENSSL_EXPORT int X509_issuer_name_cmp(const X509 *a, const X509 *b);

// X509_subject_name_cmp behaves like `X509_NAME_cmp`, but compares `a` and
// `b`'s subject names.
OPENSSL_EXPORT int X509_subject_name_cmp(const X509 *a, const X509 *b);

// X509_CRL_cmp behaves like `X509_NAME_cmp`, but compares `a` and `b`'s
// issuer names.
//
// WARNING: This function is misnamed. It does not compare other parts of the
// CRL, only the issuer fields using `X509_NAME_cmp`.
OPENSSL_EXPORT int X509_CRL_cmp(const X509_CRL *a, const X509_CRL *b);

// X509_issuer_name_hash returns the hash of `x509`'s issuer name with
// `X509_NAME_hash`.
//
// This hash is specific to the `X509_LOOKUP_add_dir` filesystem format and is
// not suitable for general-purpose X.509 name processing. It is very short, so
// there will be hash collisions. It also depends on an OpenSSL-specific
// canonicalization process.
OPENSSL_EXPORT uint32_t X509_issuer_name_hash(const X509 *x509);

// X509_subject_name_hash returns the hash of `x509`'s subject name with
// `X509_NAME_hash`.
//
// This hash is specific to the `X509_LOOKUP_add_dir` filesystem format and is
// not suitable for general-purpose X.509 name processing. It is very short, so
// there will be hash collisions. It also depends on an OpenSSL-specific
// canonicalization process.
OPENSSL_EXPORT uint32_t X509_subject_name_hash(const X509 *x509);

// X509_issuer_name_hash_old returns the hash of `x509`'s issuer name with
// `X509_NAME_hash_old`.
//
// This hash is specific to the `X509_LOOKUP_add_dir` filesystem format and is
// not suitable for general-purpose X.509 name processing. It is very short, so
// there will be hash collisions.
OPENSSL_EXPORT uint32_t X509_issuer_name_hash_old(const X509 *x509);

// X509_subject_name_hash_old returns the hash of `x509`'s usjbect name with
// `X509_NAME_hash_old`.
//
// This hash is specific to the `X509_LOOKUP_add_dir` filesystem format and is
// not suitable for general-purpose X.509 name processing. It is very short, so
// there will be hash collisions.
OPENSSL_EXPORT uint32_t X509_subject_name_hash_old(const X509 *x509);


// ex_data functions.
//
// See `ex_data.h` for details.

OPENSSL_EXPORT int X509_get_ex_new_index(long argl, void *argp,
                                         CRYPTO_EX_unused *unused,
                                         CRYPTO_EX_dup *dup_unused,
                                         CRYPTO_EX_free *free_func);
OPENSSL_EXPORT int X509_set_ex_data(X509 *r, int idx, void *arg);
OPENSSL_EXPORT void *X509_get_ex_data(X509 *r, int idx);

OPENSSL_EXPORT int X509_STORE_CTX_get_ex_new_index(long argl, void *argp,
                                                   CRYPTO_EX_unused *unused,
                                                   CRYPTO_EX_dup *dup_unused,
                                                   CRYPTO_EX_free *free_func);
OPENSSL_EXPORT int X509_STORE_CTX_set_ex_data(X509_STORE_CTX *ctx, int idx,
                                              void *data);
OPENSSL_EXPORT void *X509_STORE_CTX_get_ex_data(X509_STORE_CTX *ctx, int idx);

#define X509_STORE_CTX_set_app_data(ctx, data) \
  X509_STORE_CTX_set_ex_data(ctx, 0, data)
#define X509_STORE_CTX_get_app_data(ctx) X509_STORE_CTX_get_ex_data(ctx, 0)


// Hashing and signing ASN.1 structures.

// ASN1_digest serializes `data` with `i2d` and then hashes the result with
// `type`. On success, it returns one, writes the digest to `md`, and sets
// `*len` to the digest length if non-NULL. On error, it returns zero.
//
// `EVP_MD_CTX_size` bytes are written, which is at most `EVP_MAX_MD_SIZE`. The
// buffer must have sufficient space for this output.
OPENSSL_EXPORT int ASN1_digest(i2d_of_void *i2d, const EVP_MD *type, char *data,
                               unsigned char *md, unsigned int *len);

// ASN1_item_digest serializes `data` with `it` and then hashes the result with
// `type`. On success, it returns one, writes the digest to `md`, and sets
// `*len` to the digest length if non-NULL. On error, it returns zero.
//
// `EVP_MD_CTX_size` bytes are written, which is at most `EVP_MAX_MD_SIZE`. The
// buffer must have sufficient space for this output.
//
// WARNING: `data` must be a pointer with the same type as `it`'s corresponding
// C type. Using the wrong type is a potentially exploitable memory error.
OPENSSL_EXPORT int ASN1_item_digest(const ASN1_ITEM *it, const EVP_MD *type,
                                    void *data, unsigned char *md,
                                    unsigned int *len);

// ASN1_item_verify serializes `data` with `it` and then verifies `signature` is
// a valid signature for the result with `algor1` and `pkey`. It returns one on
// success and zero on error. The signature and algorithm are interpreted as in
// X.509.
//
// WARNING: `data` must be a pointer with the same type as `it`'s corresponding
// C type. Using the wrong type is a potentially exploitable memory error.
OPENSSL_EXPORT int ASN1_item_verify(const ASN1_ITEM *it,
                                    const X509_ALGOR *algor1,
                                    const ASN1_BIT_STRING *signature,
                                    void *data, EVP_PKEY *pkey);

// ASN1_item_sign serializes `data` with `it` and then signs the result with
// the private key `pkey`. It returns the length of the signature on success and
// zero on error. On success, it writes the signature to `signature` and the
// signature algorithm to each of `algor1` and `algor2`. Either of `algor1` or
// `algor2` may be NULL to ignore them. This function uses digest algorithm
// `md`, or `pkey`'s default if NULL. Other signing parameters use `pkey`'s
// defaults. To customize them, use `ASN1_item_sign_ctx`.
//
// `algor1` and `algor2` may point into part of `asn` and will be updated before
// `asn` is serialized.
//
// WARNING: `data` must be a pointer with the same type as `it`'s corresponding
// C type. Using the wrong type is a potentially exploitable memory error.
OPENSSL_EXPORT int ASN1_item_sign(const ASN1_ITEM *it, X509_ALGOR *algor1,
                                  X509_ALGOR *algor2,
                                  ASN1_BIT_STRING *signature, void *data,
                                  EVP_PKEY *pkey, const EVP_MD *type);

// ASN1_item_sign_ctx behaves like `ASN1_item_sign` except the signature is
// signed with `ctx`, `ctx`, which must have been initialized with
// `EVP_DigestSignInit`. The caller should configure the corresponding
// `EVP_PKEY_CTX` with any additional parameters before calling this function.
//
// On success or failure, this function mutates `ctx` and resets it to the empty
// state. Caller should not rely on its contents after the function returns.
//
// `algor1` and `algor2` may point into part of `asn` and will be updated before
// `asn` is serialized.
//
// WARNING: `data` must be a pointer with the same type as `it`'s corresponding
// C type. Using the wrong type is a potentially exploitable memory error.
OPENSSL_EXPORT int ASN1_item_sign_ctx(const ASN1_ITEM *it, X509_ALGOR *algor1,
                                      X509_ALGOR *algor2,
                                      ASN1_BIT_STRING *signature, void *asn,
                                      EVP_MD_CTX *ctx);


// Verification internals.
//
// The following functions expose portions of certificate validation. They are
// exported for compatibility with existing callers, or to support some obscure
// use cases. Most callers, however, will not need these functions and should
// instead use `X509_STORE_CTX` APIs.

// X509_supported_extension returns one if `ex` is a critical X.509 certificate
// extension, supported by `X509_verify_cert`, and zero otherwise.
//
// Note this function only reports certificate extensions (as opposed to CRL or
// CRL extensions), and only extensions that are expected to be marked critical.
// Additionally, `X509_verify_cert` checks for unsupported critical extensions
// internally, so most callers will not need to call this function separately.
OPENSSL_EXPORT int X509_supported_extension(const X509_EXTENSION *ex);

// X509_check_ca returns one if `x509` may be considered a CA certificate,
// according to basic constraints and key usage extensions. Otherwise, it
// returns zero. If `x509` is an X509v1 certificate, and thus has no extensions,
// it is considered eligible.
//
// This function returning one does not indicate that `x509` is trusted, only
// that it is eligible to be a CA.
OPENSSL_EXPORT int X509_check_ca(const X509 *x509);

// X509_check_issued checks if `issuer` and `subject`'s name, authority key
// identifier, and key usage fields allow `issuer` to have issued `subject`. It
// returns `X509_V_OK` on success and an `X509_V_ERR_*` value otherwise.
//
// This function does not check the signature on `subject`. Rather, it is
// intended to prune the set of possible issuer certificates during
// path-building.
OPENSSL_EXPORT int X509_check_issued(const X509 *issuer, const X509 *subject);

// NAME_CONSTRAINTS_check checks if `x509` satisfies name constraints in `nc`.
// It returns `X509_V_OK` on success and some `X509_V_ERR_*` constant on error.
OPENSSL_EXPORT int NAME_CONSTRAINTS_check(const X509 *x509,
                                          const NAME_CONSTRAINTS *nc);

// X509_check_host checks if `x509` matches the DNS name `chk`. It returns one
// on match, zero on mismatch, or a negative number on error. `flags` should be
// some combination of `X509_CHECK_FLAG_*` and modifies the behavior. On match,
// if `out_peername` is non-NULL, it additionally sets `*out_peername` to a
// newly-allocated, NUL-terminated string containing the DNS name or wildcard in
// the certificate which matched. The caller must then free `*out_peername` with
// `OPENSSL_free` when done.
//
// By default, both subject alternative names and the subject's common name
// attribute are checked. The latter has long been deprecated, so callers should
// include `X509_CHECK_FLAG_NEVER_CHECK_SUBJECT` in `flags` to use the standard
// behavior. https://crbug.com/boringssl/464 tracks fixing the default.
//
// This function does not check if `x509` is a trusted certificate, only if,
// were it trusted, it would match `chk`.
//
// WARNING: This function differs from the usual calling convention and may
// return either 0 or a negative number on error.
//
// TODO(davidben): Make the error case also return zero.
OPENSSL_EXPORT int X509_check_host(const X509 *x509, const char *chk,
                                   size_t chklen, unsigned int flags,
                                   char **out_peername);

// X509_check_email checks if `x509` matches the email address `chk`. It returns
// one on match, zero on mismatch, or a negative number on error. `flags` should
// be some combination of `X509_CHECK_FLAG_*` and modifies the behavior.
//
// By default, both subject alternative names and the subject's email address
// attribute are checked. The `X509_CHECK_FLAG_NEVER_CHECK_SUBJECT` flag may be
// used to change this behavior.
//
// This function does not check if `x509` is a trusted certificate, only if,
// were it trusted, it would match `chk`.
//
// WARNING: This function differs from the usual calling convention and may
// return either 0 or a negative number on error.
//
// TODO(davidben): Make the error case also return zero.
OPENSSL_EXPORT int X509_check_email(const X509 *x509, const char *chk,
                                    size_t chklen, unsigned int flags);

// X509_check_ip checks if `x509` matches the IP address `chk`. The IP address
// is represented in byte form and should be 4 bytes for an IPv4 address and 16
// bytes for an IPv6 address. It returns one on match, zero on mismatch, or a
// negative number on error. `flags` should be some combination of
// `X509_CHECK_FLAG_*` and modifies the behavior.
//
// This function does not check if `x509` is a trusted certificate, only if,
// were it trusted, it would match `chk`.
//
// WARNING: This function differs from the usual calling convention and may
// return either 0 or a negative number on error.
//
// TODO(davidben): Make the error case also return zero.
OPENSSL_EXPORT int X509_check_ip(const X509 *x509, const uint8_t *chk,
                                 size_t chklen, unsigned int flags);

// X509_check_ip_asc behaves like `X509_check_ip` except the IP address is
// specified in textual form in `ipasc`.
//
// WARNING: This function differs from the usual calling convention and may
// return either 0 or a negative number on error.
//
// TODO(davidben): Make the error case also return zero.
OPENSSL_EXPORT int X509_check_ip_asc(const X509 *x509, const char *ipasc,
                                     unsigned int flags);

// X509_STORE_CTX_get1_issuer looks up a candidate trusted issuer for `x509` out
// of `ctx`'s `X509_STORE`, based on the criteria in `X509_check_issued`. If one
// was found, it returns one and sets `*out_issuer` to the issuer. The caller
// must release `*out_issuer` with `X509_free` when done. If none was found, it
// returns zero and leaves `*out_issuer` unchanged.
//
// This function only searches for trusted issuers. It does not consider
// untrusted intermediates passed in to `X509_STORE_CTX_init`.
OPENSSL_EXPORT int X509_STORE_CTX_get1_issuer(X509 **out_issuer,
                                              X509_STORE_CTX *ctx,
                                              const X509 *x509);

// X509_check_purpose performs checks if `x509`'s basic constraints, key usage,
// and extended key usage extensions for the specified purpose. `purpose` should
// be one of `X509_PURPOSE_*` constants. See `X509_VERIFY_PARAM_set_purpose` for
// details. It returns one if `x509`'s extensions are consistent with `purpose`
// and zero otherwise. If `ca` is non-zero, `x509` is checked as a CA
// certificate. Otherwise, it is checked as an end-entity certificate.
//
// If `purpose` is -1, this function performs no purpose checks, but it parses
// some extensions in `x509` and may return zero on syntax error. Historically,
// callers primarily used this function to trigger this parsing, but this is no
// longer necessary. Functions acting on `X509` will internally parse as needed.
OPENSSL_EXPORT int X509_check_purpose(X509 *x509, int purpose, int ca);

#define X509_TRUST_TRUSTED 1
#define X509_TRUST_REJECTED 2
#define X509_TRUST_UNTRUSTED 3

// X509_check_trust checks if `x509` is a valid trust anchor for trust type
// `id`. See `X509_VERIFY_PARAM_set_trust` for details. It returns
// `X509_TRUST_TRUSTED` if `x509` is a trust anchor, `X509_TRUST_REJECTED` if it
// was distrusted, and `X509_TRUST_UNTRUSTED` otherwise. `id` should be one of
// the `X509_TRUST_*` constants, or zero to indicate the default behavior.
// `flags` should be zero and is ignored.
OPENSSL_EXPORT int X509_check_trust(X509 *x509, int id, int flags);

// X509_STORE_CTX_get1_certs returns a newly-allocated stack containing all
// trusted certificates in `ctx`'s `X509_STORE` whose subject matches `name`, or
// NULL on error. The caller must release the result with `sk_X509_pop_free` and
// `X509_free` when done.
OPENSSL_EXPORT STACK_OF(X509) *X509_STORE_CTX_get1_certs(X509_STORE_CTX *ctx,
                                                         const X509_NAME *name);

// X509_STORE_CTX_get1_crls returns a newly-allocated stack containing all
// CRLs in `ctx`'s `X509_STORE` whose subject matches `name`, or NULL on error.
// The caller must release the result with `sk_X509_CRL_pop_free` and
// `X509_CRL_free` when done.
OPENSSL_EXPORT STACK_OF(X509_CRL) *X509_STORE_CTX_get1_crls(
    X509_STORE_CTX *ctx, const X509_NAME *name);

// X509_STORE_CTX_get_by_subject looks up an object of type `type` in `ctx`'s
// `X509_STORE` that matches `name`. `type` should be one of the `X509_LU_*`
// constants to indicate the type of object. If a match was found, it stores the
// result in `ret` and returns one. Otherwise, it returns zero. If multiple
// objects match, this function outputs an arbitrary one.
//
// WARNING: `ret` must be in the empty state, as returned by `X509_OBJECT_new`.
// Otherwise, the object currently in `ret` will be leaked when overwritten.
// https://crbug.com/boringssl/685 tracks fixing this.
//
// WARNING: Multiple trusted certificates or CRLs may share a name. In this
// case, this function returns an arbitrary match. Use
// `X509_STORE_CTX_get1_certs` or `X509_STORE_CTX_get1_crls` instead.
OPENSSL_EXPORT int X509_STORE_CTX_get_by_subject(X509_STORE_CTX *ctx, int type,
                                                 const X509_NAME *name,
                                                 X509_OBJECT *ret);


// X.509 information.
//
// `X509_INFO` is the return type for `PEM_X509_INFO_read_bio`, defined in
// <openssl/pem.h>. It is used to store a certificate, CRL, or private key. This
// type is defined in this header for OpenSSL compatibility.

struct private_key_st {
  EVP_PKEY *dec_pkey;
} /* X509_PKEY */;

struct X509_info_st {
  X509 *x509;
  X509_CRL *crl;
  X509_PKEY *x_pkey;

  EVP_CIPHER_INFO enc_cipher;
  int enc_len;
  char *enc_data;
} /* X509_INFO */;

DEFINE_STACK_OF(X509_INFO)

// X509_INFO_free releases memory associated with `info`.
OPENSSL_EXPORT void X509_INFO_free(X509_INFO *info);


// Deprecated custom extension registration.
//
// The following functions allow callers to register custom extensions for use
// with `X509V3_EXT_d2i` and related functions. This mechanism is deprecated and
// will be removed in the future. As discussed in `X509V3_EXT_add`, it is not
// possible to safely register a custom extension without risking race
// conditions and memory errors when linked with other users of BoringSSL.
//
// Moreover, it is not necessary to register a custom extension to process
// extensions unknown to BoringSSL. Registration does not impact certificate
// verification. Caller should instead use functions such as
// `ASN1_OBJECT_create`, `X509_get_ext_by_OBJ`, `X509_EXTENSION_get_data`, and
// `X509_EXTENSION_create_by_OBJ` to inspect or create extensions directly.

// The following function pointer types are used in `X509V3_EXT_METHOD`.
typedef void *(*X509V3_EXT_NEW)(void);
typedef void (*X509V3_EXT_FREE)(void *ext);
typedef void *(*X509V3_EXT_D2I)(void *ext, const uint8_t **inp, long len);
typedef int (*X509V3_EXT_I2D)(void *ext, uint8_t **outp);
typedef STACK_OF(CONF_VALUE) *(*X509V3_EXT_I2V)(const X509V3_EXT_METHOD *method,
                                                void *ext,
                                                STACK_OF(CONF_VALUE) *extlist);
typedef void *(*X509V3_EXT_V2I)(const X509V3_EXT_METHOD *method,
                                const X509V3_CTX *ctx,
                                const STACK_OF(CONF_VALUE) *values);
typedef char *(*X509V3_EXT_I2S)(const X509V3_EXT_METHOD *method, void *ext);
typedef void *(*X509V3_EXT_S2I)(const X509V3_EXT_METHOD *method,
                                const X509V3_CTX *ctx, const char *str);
typedef int (*X509V3_EXT_I2R)(const X509V3_EXT_METHOD *method, void *ext,
                              BIO *out, int indent);
typedef void *(*X509V3_EXT_R2I)(const X509V3_EXT_METHOD *method,
                                const X509V3_CTX *ctx, const char *str);

// A v3_ext_method, aka `X509V3_EXT_METHOD`, is a deprecated type which defines
// a custom extension.
struct v3_ext_method {
  // ext_nid is the NID of the extension.
  int ext_nid;

  // ext_flags is a combination of `X509V3_EXT_*` constants.
  int ext_flags;

  // it determines how values of this extension are allocated, released, parsed,
  // and marshalled. This must be non-NULL.
  ASN1_ITEM_EXP *it;

  // The following functions are ignored in favor of `it`. They are retained in
  // the struct only for source compatibility with existing struct definitions.
  X509V3_EXT_NEW ext_new;
  X509V3_EXT_FREE ext_free;
  X509V3_EXT_D2I d2i;
  X509V3_EXT_I2D i2d;

  // The following functions are used for string extensions.
  X509V3_EXT_I2S i2s;
  X509V3_EXT_S2I s2i;

  // The following functions are used for multi-valued extensions.
  X509V3_EXT_I2V i2v;
  X509V3_EXT_V2I v2i;

  // The following functions are used for "raw" extensions, which implement
  // custom printing behavior.
  X509V3_EXT_I2R i2r;
  X509V3_EXT_R2I r2i;

  void *usr_data;  // Any extension specific data
} /* X509V3_EXT_METHOD */;

// X509V3_EXT_MULTILINE causes the result of an `X509V3_EXT_METHOD`'s `i2v`
// function to be printed on separate lines, rather than separated by commas.
#define X509V3_EXT_MULTILINE 0x4

// X509V3_EXT_get returns the `X509V3_EXT_METHOD` corresponding to `ext`'s
// extension type, or NULL if none was registered.
OPENSSL_EXPORT const X509V3_EXT_METHOD *X509V3_EXT_get(
    const X509_EXTENSION *ext);

// X509V3_EXT_get_nid returns the `X509V3_EXT_METHOD` corresponding to `nid`, or
// NULL if none was registered.
OPENSSL_EXPORT const X509V3_EXT_METHOD *X509V3_EXT_get_nid(int nid);

// X509V3_EXT_add registers `ext` as a custom extension for the extension type
// `ext->ext_nid`. `ext` must be valid for the remainder of the address space's
// lifetime. It returns one on success and zero on error.
//
// WARNING: This function modifies global state. If other code in the same
// address space also registers an extension with type `ext->ext_nid`, the two
// registrations will conflict. Which registration takes effect is undefined. If
// the two registrations use incompatible in-memory representations, code
// expecting the other registration will then cast a type to the wrong type,
// resulting in a potentially exploitable memory error. This conflict can also
// occur if BoringSSL later adds support for `ext->ext_nid`, with a different
// in-memory representation than the one expected by `ext`.
//
// This function, additionally, is not thread-safe and cannot be called
// concurrently with any other BoringSSL function.
//
// As a result, it is impossible to safely use this function. Registering a
// custom extension has no impact on certificate verification so, instead,
// callers should simply handle the custom extension with the byte-based
// `X509_EXTENSION` APIs directly. Registering `ext` with the library has little
// practical value.
OPENSSL_EXPORT OPENSSL_DEPRECATED int X509V3_EXT_add(X509V3_EXT_METHOD *ext);

// X509V3_EXT_add_alias registers a custom extension with NID `nid_to`. The
// corresponding ASN.1 type is copied from `nid_from`. It returns one on success
// and zero on error.
//
// WARNING: Do not use this function. See `X509V3_EXT_add`.
OPENSSL_EXPORT OPENSSL_DEPRECATED int X509V3_EXT_add_alias(int nid_to,
                                                           int nid_from);


// Deprecated config-based extension creation.
//
// The following functions allow specifying X.509 extensions using OpenSSL's
// config file syntax, from the OpenSSL command-line tool. They are retained,
// for now, for compatibility with legacy software but may be removed in the
// future. Construct the extensions using the typed C APIs instead.
//
// Callers should especially avoid these functions if passing in non-constant
// values. They use ad-hoc, string-based formats which are prone to injection
// vulnerabilities. For a CA, this means using them risks misissuance.
//
// These functions are not safe to use with untrusted inputs. The string formats
// may implicitly reference context information and, in OpenSSL (though not
// BoringSSL), one even allows reading arbitrary files. Many formats can also
// produce far larger outputs than their inputs, so untrusted inputs may lead to
// denial-of-service attacks. Finally, the parsers see much less testing and
// review than most of the library and may have bugs including memory leaks or
// crashes.

// v3_ext_ctx, aka `X509V3_CTX`, contains additional context information for
// constructing extensions. Some string formats reference additional values in
// these objects. It must be initialized with `X509V3_set_ctx` or
// `X509V3_set_ctx_test` before use.
struct v3_ext_ctx {
  int flags;
  const X509 *issuer_cert;
  const X509 *subject_cert;
  const X509_REQ *subject_req;
  const X509_CRL *crl;
  const CONF *db;
};

#define X509V3_CTX_TEST 0x1

// X509V3_set_ctx initializes `ctx` with the specified objects. Some string
// formats will reference fields in these objects. Each object may be NULL to
// omit it, in which case those formats cannot be used. `flags` should be zero,
// unless called via `X509V3_set_ctx_test`.
//
// `issuer`, `subject`, `req`, and `crl`, if non-NULL, must outlive `ctx`.
OPENSSL_EXPORT void X509V3_set_ctx(X509V3_CTX *ctx, const X509 *issuer,
                                   const X509 *subject, const X509_REQ *req,
                                   const X509_CRL *crl, int flags);

// X509V3_set_ctx_test calls `X509V3_set_ctx` without any reference objects and
// mocks out some features that use them. The resulting extensions may be
// incomplete and should be discarded. This can be used to partially validate
// syntax.
//
// TODO(davidben): Can we remove this?
#define X509V3_set_ctx_test(ctx) \
  X509V3_set_ctx(ctx, NULL, NULL, NULL, NULL, X509V3_CTX_TEST)

// X509V3_set_nconf sets `ctx` to use `conf` as the config database. `ctx` must
// have previously been initialized by `X509V3_set_ctx` or
// `X509V3_set_ctx_test`. Some string formats will reference sections in `conf`.
// `conf` may be NULL, in which case these formats cannot be used. If non-NULL,
// `conf` must outlive `ctx`.
OPENSSL_EXPORT void X509V3_set_nconf(X509V3_CTX *ctx, const CONF *conf);

// X509V3_set_ctx_nodb calls `X509V3_set_nconf` with no config database.
#define X509V3_set_ctx_nodb(ctx) X509V3_set_nconf(ctx, NULL)

// X509V3_EXT_nconf constructs an extension of type specified by `name`, and
// value specified by `value`. It returns a newly-allocated `X509_EXTENSION`
// object on success, or NULL on error. `conf` and `ctx` specify additional
// information referenced by some formats. Either `conf` or `ctx` may be NULL,
// in which case features which use it will be disabled.
//
// If non-NULL, `ctx` must be initialized with `X509V3_set_ctx` or
// `X509V3_set_ctx_test`.
//
// Both `conf` and `ctx` provide a `CONF` object. When `ctx` is non-NULL, most
// features use the `ctx` copy, configured with `X509V3_set_ctx`, but some use
// `conf`. Callers should ensure the two match to avoid surprisingly behavior.
OPENSSL_EXPORT X509_EXTENSION *X509V3_EXT_nconf(const CONF *conf,
                                                const X509V3_CTX *ctx,
                                                const char *name,
                                                const char *value);

// X509V3_EXT_nconf_nid behaves like `X509V3_EXT_nconf`, except the extension
// type is specified as a NID.
OPENSSL_EXPORT X509_EXTENSION *X509V3_EXT_nconf_nid(const CONF *conf,
                                                    const X509V3_CTX *ctx,
                                                    int ext_nid,
                                                    const char *value);

// X509V3_EXT_conf_nid calls `X509V3_EXT_nconf_nid`. `conf` must be NULL.
OPENSSL_EXPORT X509_EXTENSION *X509V3_EXT_conf_nid(CRYPTO_MUST_BE_NULL *conf,
                                                   const X509V3_CTX *ctx,
                                                   int ext_nid,
                                                   const char *value);

// X509V3_EXT_add_nconf_sk looks up the section named `section` in `conf`. For
// each `CONF_VALUE` in the section, it constructs an extension as in
// `X509V3_EXT_nconf`, taking `name` and `value` from the `CONF_VALUE`. Each new
// extension is appended to `*sk`. If `*sk` is non-NULL, and at least one
// extension is added, it sets `*sk` to a newly-allocated
// `STACK_OF(X509_EXTENSION)`. It returns one on success and zero on error.
OPENSSL_EXPORT int X509V3_EXT_add_nconf_sk(const CONF *conf,
                                           const X509V3_CTX *ctx,
                                           const char *section,
                                           STACK_OF(X509_EXTENSION) **sk);

// X509V3_EXT_add_nconf adds extensions to `cert` as in
// `X509V3_EXT_add_nconf_sk`. It returns one on success and zero on error.
OPENSSL_EXPORT int X509V3_EXT_add_nconf(const CONF *conf, const X509V3_CTX *ctx,
                                        const char *section, X509 *cert);

// X509V3_EXT_REQ_add_nconf adds extensions to `req` as in
// `X509V3_EXT_add_nconf_sk`. It returns one on success and zero on error.
OPENSSL_EXPORT int X509V3_EXT_REQ_add_nconf(const CONF *conf,
                                            const X509V3_CTX *ctx,
                                            const char *section, X509_REQ *req);

// X509V3_EXT_CRL_add_nconf adds extensions to `crl` as in
// `X509V3_EXT_add_nconf_sk`. It returns one on success and zero on error.
OPENSSL_EXPORT int X509V3_EXT_CRL_add_nconf(const CONF *conf,
                                            const X509V3_CTX *ctx,
                                            const char *section, X509_CRL *crl);

// i2s_ASN1_OCTET_STRING returns a human-readable representation of `oct` as a
// newly-allocated, NUL-terminated string, or NULL on error. `method` is
// ignored. The caller must release the result with `OPENSSL_free` when done.
OPENSSL_EXPORT char *i2s_ASN1_OCTET_STRING(const X509V3_EXT_METHOD *method,
                                           const ASN1_OCTET_STRING *oct);

// s2i_ASN1_OCTET_STRING decodes `str` as a hexadecimal byte string, with
// optional colon separators between bytes. It returns a newly-allocated
// `ASN1_OCTET_STRING` with the result on success, or NULL on error. `method`
// and `ctx` are ignored.
OPENSSL_EXPORT ASN1_OCTET_STRING *s2i_ASN1_OCTET_STRING(
    const X509V3_EXT_METHOD *method, const X509V3_CTX *ctx, const char *str);

// i2s_ASN1_INTEGER returns a human-readable representation of `aint` as a
// newly-allocated, NUL-terminated string, or NULL on error. `method` is
// ignored. The caller must release the result with `OPENSSL_free` when done.
OPENSSL_EXPORT char *i2s_ASN1_INTEGER(const X509V3_EXT_METHOD *method,
                                      const ASN1_INTEGER *aint);

// s2i_ASN1_INTEGER decodes `value` as the ASCII representation of an integer,
// and returns a newly-allocated `ASN1_INTEGER` containing the result, or NULL
// on error. `method` is ignored. If `value` begins with "0x" or "0X", the input
// is decoded in hexadecimal, otherwise decimal.
OPENSSL_EXPORT ASN1_INTEGER *s2i_ASN1_INTEGER(const X509V3_EXT_METHOD *method,
                                              const char *value);

// i2s_ASN1_ENUMERATED returns a human-readable representation of `aint` as a
// newly-allocated, NUL-terminated string, or NULL on error. `method` is
// ignored. The caller must release the result with `OPENSSL_free` when done.
OPENSSL_EXPORT char *i2s_ASN1_ENUMERATED(const X509V3_EXT_METHOD *method,
                                         const ASN1_ENUMERATED *aint);

// X509V3_conf_free releases memory associated with `CONF_VALUE`.
OPENSSL_EXPORT void X509V3_conf_free(CONF_VALUE *val);

// i2v_GENERAL_NAME serializes `gen` as a `CONF_VALUE`. If `ret` is non-NULL, it
// appends the value to `ret` and returns `ret` on success or NULL on error. If
// it returns NULL, the caller is still responsible for freeing `ret`. If `ret`
// is NULL, it returns a newly-allocated `STACK_OF(CONF_VALUE)` containing the
// result. `method` is ignored. When done, the caller should release the result
// with `sk_CONF_VALUE_pop_free` and `X509V3_conf_free`.
//
// Do not use this function. This is an internal implementation detail of the
// human-readable print functions. If extracting a SAN list from a certificate,
// look at `gen` directly.
OPENSSL_EXPORT STACK_OF(CONF_VALUE) *i2v_GENERAL_NAME(
    const X509V3_EXT_METHOD *method, const GENERAL_NAME *gen,
    STACK_OF(CONF_VALUE) *ret);

// i2v_GENERAL_NAMES serializes `gen` as a list of `CONF_VALUE`s. If `ret` is
// non-NULL, it appends the values to `ret` and returns `ret` on success or NULL
// on error. If it returns NULL, the caller is still responsible for freeing
// `ret`. If `ret` is NULL, it returns a newly-allocated `STACK_OF(CONF_VALUE)`
// containing the results. `method` is ignored.
//
// Do not use this function. This is an internal implementation detail of the
// human-readable print functions. If extracting a SAN list from a certificate,
// look at `gen` directly.
OPENSSL_EXPORT STACK_OF(CONF_VALUE) *i2v_GENERAL_NAMES(
    const X509V3_EXT_METHOD *method, const GENERAL_NAMES *gen,
    STACK_OF(CONF_VALUE) *extlist);

// a2i_IPADDRESS decodes `ipasc` as the textual representation of an IPv4 or
// IPv6 address. On success, it returns a newly-allocated `ASN1_OCTET_STRING`
// containing the decoded IP address. IPv4 addresses are represented as 4-byte
// strings and IPv6 addresses as 16-byte strings. On failure, it returns NULL.
OPENSSL_EXPORT ASN1_OCTET_STRING *a2i_IPADDRESS(const char *ipasc);

// a2i_IPADDRESS_NC decodes `ipasc` as the textual representation of an IPv4 or
// IPv6 address range. On success, it returns a newly-allocated
// `ASN1_OCTET_STRING` containing the decoded IP address, followed by the
// decoded mask. IPv4 ranges are represented as 8-byte strings and IPv6 ranges
// as 32-byte strings. On failure, it returns NULL.
//
// The text format decoded by this function is not the standard CIDR notation.
// Instead, the mask after the "/" is represented as another IP address. For
// example, "192.168.0.0/16" would be written "192.168.0.0/255.255.0.0".
OPENSSL_EXPORT ASN1_OCTET_STRING *a2i_IPADDRESS_NC(const char *ipasc);


// Deprecated functions.

// X509_get_notBefore returns `x509`'s notBefore time. Note this function is not
// const-correct for legacy reasons. Use `X509_get0_notBefore` or
// `X509_getm_notBefore` instead.
OPENSSL_EXPORT ASN1_TIME *X509_get_notBefore(const X509 *x509);

// X509_get_notAfter returns `x509`'s notAfter time. Note this function is not
// const-correct for legacy reasons. Use `X509_get0_notAfter` or
// `X509_getm_notAfter` instead.
OPENSSL_EXPORT ASN1_TIME *X509_get_notAfter(const X509 *x509);

// X509_set_notBefore calls `X509_set1_notBefore`. Use `X509_set1_notBefore`
// instead.
OPENSSL_EXPORT int X509_set_notBefore(X509 *x509, const ASN1_TIME *tm);

// X509_set_notAfter calls `X509_set1_notAfter`. Use `X509_set1_notAfter`
// instead.
OPENSSL_EXPORT int X509_set_notAfter(X509 *x509, const ASN1_TIME *tm);

// X509_CRL_get_lastUpdate returns a mutable pointer to `crl`'s thisUpdate time.
// The OpenSSL API refers to this field as lastUpdate.
//
// Use `X509_CRL_get0_lastUpdate` or `X509_CRL_set1_lastUpdate` instead.
OPENSSL_EXPORT ASN1_TIME *X509_CRL_get_lastUpdate(X509_CRL *crl);

// X509_CRL_get_nextUpdate returns a mutable pointer to `crl`'s nextUpdate time,
// or NULL if `crl` has none. Use `X509_CRL_get0_nextUpdate` or
// `X509_CRL_set1_nextUpdate` instead.
OPENSSL_EXPORT ASN1_TIME *X509_CRL_get_nextUpdate(X509_CRL *crl);

// X509_extract_key is a legacy alias to `X509_get_pubkey`. Use
// `X509_get_pubkey` instead.
#define X509_extract_key(x) X509_get_pubkey(x)

// X509_REQ_extract_key is a legacy alias for `X509_REQ_get_pubkey`.
#define X509_REQ_extract_key(a) X509_REQ_get_pubkey(a)

// X509_name_cmp is a legacy alias for `X509_NAME_cmp`.
#define X509_name_cmp(a, b) X509_NAME_cmp((a), (b))

// The following symbols are deprecated aliases to `X509_CRL_set1_*`.
#define X509_CRL_set_lastUpdate X509_CRL_set1_lastUpdate
#define X509_CRL_set_nextUpdate X509_CRL_set1_nextUpdate

// X509_get_serialNumber returns a mutable pointer to `x509`'s serial number.
// Prefer `X509_get0_serialNumber`.
OPENSSL_EXPORT ASN1_INTEGER *X509_get_serialNumber(X509 *x509);

// X509_NAME_get_text_by_OBJ finds the first attribute with type `obj` in
// `name`. If found, it writes the value's UTF-8 representation to `buf`.
// followed by a NUL byte, and returns the number of bytes in the output,
// excluding the NUL byte. This is unlike OpenSSL which returns the raw
// ASN1_STRING data. The UTF-8 encoding of the `ASN1_STRING` may not contain a 0
// codepoint.
//
// This function writes at most `len` bytes, including the NUL byte.  If `buf`
// is NULL, it writes nothing and returns the number of bytes in the
// output, excluding the NUL byte that would be required for the full UTF-8
// output.
//
// This function may return -1 if an error occurs for any reason, including the
// value not being a recognized string type, `len` being of insufficient size to
// hold the full UTF-8 encoding and NUL byte, memory allocation failures, an
// object with type `obj` not existing in `name`, or if the UTF-8 encoding of
// the string contains a zero byte.
OPENSSL_EXPORT int X509_NAME_get_text_by_OBJ(const X509_NAME *name,
                                             const ASN1_OBJECT *obj, char *buf,
                                             int len);

// X509_NAME_get_text_by_NID behaves like `X509_NAME_get_text_by_OBJ` except it
// finds an attribute of type `nid`, which should be one of the `NID_*`
// constants.
OPENSSL_EXPORT int X509_NAME_get_text_by_NID(const X509_NAME *name, int nid,
                                             char *buf, int len);

// X509_STORE_CTX_get0_parent_ctx returns NULL.
OPENSSL_EXPORT X509_STORE_CTX *X509_STORE_CTX_get0_parent_ctx(
    const X509_STORE_CTX *ctx);

// X509_OBJECT_free_contents sets `obj` to the empty object, freeing any values
// that were previously there.
//
// TODO(davidben): Unexport this function after rust-openssl is fixed to no
// longer call it.
OPENSSL_EXPORT void X509_OBJECT_free_contents(X509_OBJECT *obj);

// X509_LOOKUP_free releases memory associated with `ctx`. This function should
// never be used outside the library. No function in the public API hands
// ownership of an `X509_LOOKUP` to the caller.
//
// TODO(davidben): Unexport this function after rust-openssl is fixed to no
// longer call it.
OPENSSL_EXPORT void X509_LOOKUP_free(X509_LOOKUP *ctx);

// X509_STORE_CTX_cleanup resets `ctx` to the empty state.
//
// This function is a remnant of when `X509_STORE_CTX` was stack-allocated and
// should not be used. If releasing `ctx`, call `X509_STORE_CTX_free`. If
// reusing `ctx` for a new verification, release the old one and create a new
// one.
OPENSSL_EXPORT void X509_STORE_CTX_cleanup(X509_STORE_CTX *ctx);

// X509V3_add_standard_extensions returns one.
OPENSSL_EXPORT int X509V3_add_standard_extensions(void);

// The following symbols are legacy aliases for `X509_STORE_CTX` functions.
#define X509_STORE_get_by_subject X509_STORE_CTX_get_by_subject
#define X509_STORE_get1_certs X509_STORE_CTX_get1_certs
#define X509_STORE_get1_crls X509_STORE_CTX_get1_crls

// X509_STORE_CTX_get_chain is a legacy alias for `X509_STORE_CTX_get0_chain`.
OPENSSL_EXPORT STACK_OF(X509) *X509_STORE_CTX_get_chain(
    const X509_STORE_CTX *ctx);

// X509_STORE_CTX_trusted_stack is a deprecated alias for
// `X509_STORE_CTX_set0_trusted_stack`.
OPENSSL_EXPORT void X509_STORE_CTX_trusted_stack(X509_STORE_CTX *ctx,
                                                 STACK_OF(X509) *sk);

typedef int (*X509_STORE_CTX_verify_cb)(int, X509_STORE_CTX *);

// X509_STORE_CTX_set_verify_cb configures a callback function for `ctx` that is
// called multiple times during `X509_verify_cert`. The callback returns zero to
// fail verification and one to proceed. Typically, it will return `ok`, which
// preserves the default behavior. Returning one when `ok` is zero will proceed
// past some error. The callback may inspect `ctx` and the error queue to
// attempt to determine the current stage of certificate verification, but this
// is often unreliable. When synthesizing an error, callbacks should use
// `X509_STORE_CTX_set_error` to set a corresponding error.
//
// WARNING: Do not use this function. It is extremely fragile and unpredictable.
// This callback exposes implementation details of certificate verification,
// which change as the library evolves. Attempting to use it for security checks
// can introduce vulnerabilities if making incorrect assumptions about when the
// callback is called. Some errors, when suppressed, may implicitly suppress
// other errors due to internal implementation details. Additionally, overriding
// `ok` may leave `ctx` in an inconsistent state and break invariants.
//
// Instead, customize certificate verification by configuring options on the
// `X509_STORE_CTX` before verification, or applying additional checks after
// `X509_verify_cert` completes successfully.
OPENSSL_EXPORT void X509_STORE_CTX_set_verify_cb(
    X509_STORE_CTX *ctx, int (*verify_cb)(int ok, X509_STORE_CTX *ctx));

// X509_STORE_set_verify_cb acts like `X509_STORE_CTX_set_verify_cb` but sets
// the verify callback for any `X509_STORE_CTX` created from this `X509_STORE`
//
// Do not use this function. See `X509_STORE_CTX_set_verify_cb` for details.
OPENSSL_EXPORT void X509_STORE_set_verify_cb(
    X509_STORE *store, X509_STORE_CTX_verify_cb verify_cb);

// X509_STORE_set_verify_cb_func is a deprecated alias for
// `X509_STORE_set_verify_cb`.
#define X509_STORE_set_verify_cb_func(store, func) \
  X509_STORE_set_verify_cb((store), (func))

// X509_STORE_CTX_set_chain configures `ctx` to use `sk` for untrusted
// intermediate certificates to use in verification. This function is redundant
// with the `chain` parameter of `X509_STORE_CTX_init`. Use the parameter
// instead.
//
// WARNING: Despite the similar name, this function is unrelated to
// `X509_STORE_CTX_get0_chain`.
//
// WARNING: This function saves a pointer to `sk` without copying or
// incrementing reference counts. `sk` must outlive `ctx` and may not be mutated
// for the duration of the certificate verification.
OPENSSL_EXPORT void X509_STORE_CTX_set_chain(X509_STORE_CTX *ctx,
                                             STACK_OF(X509) *sk);

// The following flags do nothing. The corresponding non-standard options have
// been removed.
#define X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT 0
#define X509_CHECK_FLAG_MULTI_LABEL_WILDCARDS 0
#define X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS 0

// X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS does nothing, but is necessary in
// OpenSSL to enable standard wildcard matching. In BoringSSL, this behavior is
// always enabled.
#define X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS 0

// X509_STORE_get0_objects returns a non-owning pointer of `store`'s internal
// object list. Although this function is not const, callers must not modify
// the result of this function.
//
// WARNING: This function is not thread-safe. If `store` is shared across
// multiple threads, callers cannot safely inspect the result of this function,
// because another thread may have concurrently added to it. In particular,
// `X509_LOOKUP_add_dir` treats this list as a cache and may add to it in the
// course of certificate verification. This API additionally prevents fixing
// some quadratic worst-case behavior in `X509_STORE` and may be removed in the
// future. Use `X509_STORE_get1_objects` instead.
OPENSSL_EXPORT STACK_OF(X509_OBJECT) *X509_STORE_get0_objects(
    X509_STORE *store);

// X509_PURPOSE_get_by_sname returns the `X509_PURPOSE_*` constant corresponding
// a short name `sname`, or -1 if `sname` was not recognized.
//
// Use `X509_PURPOSE_*` constants directly instead. The short names used by this
// function look like "sslserver" or "smimeencrypt", so they do not make
// especially good APIs.
//
// This function differs from OpenSSL, which returns an "index" to be passed to
// `X509_PURPOSE_get0`, followed by `X509_PURPOSE_get_id`, to finally obtain an
// `X509_PURPOSE_*` value suitable for use with `X509_VERIFY_PARAM_set_purpose`.
OPENSSL_EXPORT int X509_PURPOSE_get_by_sname(const char *sname);

// X509_PURPOSE_get0 returns the `X509_PURPOSE` object corresponding to `id`,
// which should be one of the `X509_PURPOSE_*` constants, or NULL if none
// exists.
//
// This function differs from OpenSSL, which takes an "index", returned from
// `X509_PURPOSE_get_by_sname`. In BoringSSL, indices and `X509_PURPOSE_*` IDs
// are the same.
OPENSSL_EXPORT const X509_PURPOSE *X509_PURPOSE_get0(int id);

// X509_PURPOSE_get_id returns `purpose`'s ID. This will be one of the
// `X509_PURPOSE_*` constants.
OPENSSL_EXPORT int X509_PURPOSE_get_id(const X509_PURPOSE *purpose);

// The following constants are values for the legacy Netscape certificate type
// X.509 extension, a precursor to extended key usage. These values correspond
// to the DER encoding of the first byte of the BIT STRING. That is, 0x80 is
// bit zero and 0x01 is bit seven.
//
// TODO(davidben): These constants are only used by OpenVPN, which deprecated
// the feature in 2017. The documentation says it was removed, but they did not
// actually remove it. See if OpenVPN will accept a patch to finish this.
#define NS_SSL_CLIENT 0x80
#define NS_SSL_SERVER 0x40
#define NS_SMIME 0x20
#define NS_OBJSIGN 0x10
#define NS_SSL_CA 0x04
#define NS_SMIME_CA 0x02
#define NS_OBJSIGN_CA 0x01
#define NS_ANY_CA (NS_SSL_CA | NS_SMIME_CA | NS_OBJSIGN_CA)


// Private structures.

struct X509_algor_st {
  ASN1_OBJECT *algorithm;
  ASN1_TYPE *parameter;
} /* X509_ALGOR */;


#if defined(__cplusplus)
}  // extern C
#endif

#if !defined(BORINGSSL_NO_CXX)
extern "C++" {

BSSL_NAMESPACE_BEGIN

BORINGSSL_MAKE_DELETER(ACCESS_DESCRIPTION, ACCESS_DESCRIPTION_free)
BORINGSSL_MAKE_DELETER(AUTHORITY_KEYID, AUTHORITY_KEYID_free)
BORINGSSL_MAKE_DELETER(BASIC_CONSTRAINTS, BASIC_CONSTRAINTS_free)
// TODO(davidben): Move this to conf.h and rename to CONF_VALUE_free.
BORINGSSL_MAKE_DELETER(CONF_VALUE, X509V3_conf_free)
BORINGSSL_MAKE_DELETER(DIST_POINT, DIST_POINT_free)
BORINGSSL_MAKE_DELETER(GENERAL_NAME, GENERAL_NAME_free)
BORINGSSL_MAKE_DELETER(GENERAL_SUBTREE, GENERAL_SUBTREE_free)
BORINGSSL_MAKE_DELETER(NAME_CONSTRAINTS, NAME_CONSTRAINTS_free)
BORINGSSL_MAKE_DELETER(NETSCAPE_SPKI, NETSCAPE_SPKI_free)
BORINGSSL_MAKE_DELETER(NOTICEREF, NOTICEREF_free)
BORINGSSL_MAKE_DELETER(POLICY_CONSTRAINTS, POLICY_CONSTRAINTS_free)
BORINGSSL_MAKE_DELETER(POLICY_MAPPING, POLICY_MAPPING_free)
BORINGSSL_MAKE_DELETER(POLICYINFO, POLICYINFO_free)
BORINGSSL_MAKE_DELETER(POLICYQUALINFO, POLICYQUALINFO_free)
BORINGSSL_MAKE_DELETER(RSA_PSS_PARAMS, RSA_PSS_PARAMS_free)
BORINGSSL_MAKE_DELETER(USERNOTICE, USERNOTICE_free)
BORINGSSL_MAKE_DELETER(X509, X509_free)
BORINGSSL_MAKE_UP_REF(X509, X509_up_ref)
BORINGSSL_MAKE_DELETER(X509_ALGOR, X509_ALGOR_free)
BORINGSSL_MAKE_DELETER(X509_ATTRIBUTE, X509_ATTRIBUTE_free)
BORINGSSL_MAKE_DELETER(X509_CRL, X509_CRL_free)
BORINGSSL_MAKE_UP_REF(X509_CRL, X509_CRL_up_ref)
BORINGSSL_MAKE_DELETER(X509_EXTENSION, X509_EXTENSION_free)
BORINGSSL_MAKE_DELETER(X509_INFO, X509_INFO_free)
BORINGSSL_MAKE_DELETER(X509_LOOKUP, X509_LOOKUP_free)
BORINGSSL_MAKE_DELETER(X509_NAME, X509_NAME_free)
BORINGSSL_MAKE_DELETER(X509_NAME_ENTRY, X509_NAME_ENTRY_free)
BORINGSSL_MAKE_DELETER(X509_OBJECT, X509_OBJECT_free)
BORINGSSL_MAKE_DELETER(X509_PUBKEY, X509_PUBKEY_free)
BORINGSSL_MAKE_DELETER(X509_REQ, X509_REQ_free)
BORINGSSL_MAKE_DELETER(X509_REVOKED, X509_REVOKED_free)
BORINGSSL_MAKE_DELETER(X509_SIG, X509_SIG_free)
BORINGSSL_MAKE_DELETER(X509_STORE, X509_STORE_free)
BORINGSSL_MAKE_UP_REF(X509_STORE, X509_STORE_up_ref)
BORINGSSL_MAKE_DELETER(X509_STORE_CTX, X509_STORE_CTX_free)
BORINGSSL_MAKE_DELETER(X509_VERIFY_PARAM, X509_VERIFY_PARAM_free)

BSSL_NAMESPACE_END

}       // extern C++
#endif  // !BORINGSSL_NO_CXX

#define X509_R_AKID_MISMATCH 100
#define X509_R_BAD_PKCS7_VERSION 101
#define X509_R_BAD_X509_FILETYPE 102
#define X509_R_BASE64_DECODE_ERROR 103
#define X509_R_CANT_CHECK_DH_KEY 104
#define X509_R_CERT_ALREADY_IN_HASH_TABLE 105
#define X509_R_CRL_ALREADY_DELTA 106
#define X509_R_CRL_VERIFY_FAILURE 107
#define X509_R_IDP_MISMATCH 108
#define X509_R_INVALID_BIT_STRING_BITS_LEFT 109
#define X509_R_INVALID_DIRECTORY 110
#define X509_R_INVALID_FIELD_NAME 111
#define X509_R_INVALID_PSS_PARAMETERS 112
#define X509_R_INVALID_TRUST 113
#define X509_R_ISSUER_MISMATCH 114
#define X509_R_KEY_TYPE_MISMATCH 115
#define X509_R_KEY_VALUES_MISMATCH 116
#define X509_R_LOADING_CERT_DIR 117
#define X509_R_LOADING_DEFAULTS 118
#define X509_R_NEWER_CRL_NOT_NEWER 119
#define X509_R_NOT_PKCS7_SIGNED_DATA 120
#define X509_R_NO_CERTIFICATES_INCLUDED 121
#define X509_R_NO_CERT_SET_FOR_US_TO_VERIFY 122
#define X509_R_NO_CRLS_INCLUDED 123
#define X509_R_NO_CRL_NUMBER 124
#define X509_R_PUBLIC_KEY_DECODE_ERROR 125
#define X509_R_PUBLIC_KEY_ENCODE_ERROR 126
#define X509_R_SHOULD_RETRY 127
#define X509_R_UNKNOWN_KEY_TYPE 128
#define X509_R_UNKNOWN_NID 129
#define X509_R_UNKNOWN_PURPOSE_ID 130
#define X509_R_UNKNOWN_TRUST_ID 131
#define X509_R_UNSUPPORTED_ALGORITHM 132
#define X509_R_WRONG_LOOKUP_TYPE 133
#define X509_R_WRONG_TYPE 134
#define X509_R_NAME_TOO_LONG 135
#define X509_R_INVALID_PARAMETER 136
#define X509_R_SIGNATURE_ALGORITHM_MISMATCH 137
#define X509_R_DELTA_CRL_WITHOUT_CRL_NUMBER 138
#define X509_R_INVALID_FIELD_FOR_VERSION 139
#define X509_R_INVALID_VERSION 140
#define X509_R_NO_CERTIFICATE_FOUND 141
#define X509_R_NO_CERTIFICATE_OR_CRL_FOUND 142
#define X509_R_NO_CRL_FOUND 143
#define X509_R_INVALID_POLICY_EXTENSION 144

#endif  // OPENSSL_HEADER_X509_H