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cosmopolitan/third_party/mbedtls/x509write_crt.c
Jōshin e16a7d8f3b
flip et / noet in modelines 
`et` means `expandtab`.

```sh
rg 'vi: .* :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\)  :vi/vi: \1 xoet\2:vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2  :vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/'
```
2023-12-07 22:17:11 -05:00

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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:4;tab-width:4;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright The Mbed TLS Contributors │
│ │
│ 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 │
│ │
│ http://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. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "third_party/mbedtls/asn1write.h"
#include "third_party/mbedtls/common.h"
#include "third_party/mbedtls/error.h"
#include "third_party/mbedtls/oid.h"
#include "third_party/mbedtls/pem.h"
#include "third_party/mbedtls/platform.h"
#include "third_party/mbedtls/sha1.h"
#include "third_party/mbedtls/x509_crt.h"
asm(".ident\t\"\\n\\n\
Mbed TLS (Apache 2.0)\\n\
Copyright ARM Limited\\n\
Copyright Mbed TLS Contributors\"");
asm(".include \"libc/disclaimer.inc\"");
/*
* X.509 certificate writing
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* 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
*
* http://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.
*/
/*
* References:
* - certificates: RFC 5280, updated by RFC 6818
* - CSRs: PKCS#10 v1.7 aka RFC 2986
* - attributes: PKCS#9 v2.0 aka RFC 2985
*/
#if defined(MBEDTLS_X509_CRT_WRITE_C)
/**
* \brief Initialize a CRT writing context
*
* \param ctx CRT context to initialize
*/
void mbedtls_x509write_crt_init( mbedtls_x509write_cert *ctx )
{
mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x509write_cert ) );
mbedtls_mpi_init( &ctx->serial );
ctx->version = MBEDTLS_X509_CRT_VERSION_3;
}
/**
* \brief Free the contents of a CRT write context
*
* \param ctx CRT context to free
*/
void mbedtls_x509write_crt_free( mbedtls_x509write_cert *ctx )
{
mbedtls_mpi_free( &ctx->serial );
mbedtls_asn1_free_named_data_list( &ctx->subject );
mbedtls_asn1_free_named_data_list( &ctx->issuer );
mbedtls_asn1_free_named_data_list( &ctx->extensions );
mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x509write_cert ) );
}
/**
* \brief Set the verion for a Certificate
* Default: MBEDTLS_X509_CRT_VERSION_3
*
* \param ctx CRT context to use
* \param version version to set (MBEDTLS_X509_CRT_VERSION_1, MBEDTLS_X509_CRT_VERSION_2 or
* MBEDTLS_X509_CRT_VERSION_3)
*/
void mbedtls_x509write_crt_set_version( mbedtls_x509write_cert *ctx,
int version )
{
ctx->version = version;
}
/**
* \brief Set the MD algorithm to use for the signature
* (e.g. MBEDTLS_MD_SHA1)
*
* \param ctx CRT context to use
* \param md_alg MD algorithm to use
*/
void mbedtls_x509write_crt_set_md_alg( mbedtls_x509write_cert *ctx,
mbedtls_md_type_t md_alg )
{
ctx->md_alg = md_alg;
}
/**
* \brief Set the subject public key for the certificate
*
* \param ctx CRT context to use
* \param key public key to include
*/
void mbedtls_x509write_crt_set_subject_key( mbedtls_x509write_cert *ctx,
mbedtls_pk_context *key )
{
ctx->subject_key = key;
}
/**
* \brief Set the issuer key used for signing the certificate
*
* \param ctx CRT context to use
* \param key private key to sign with
*/
void mbedtls_x509write_crt_set_issuer_key( mbedtls_x509write_cert *ctx,
mbedtls_pk_context *key )
{
ctx->issuer_key = key;
}
/**
* \brief Set the subject name for a Certificate
* Subject names should contain a comma-separated list
* of OID types and values:
* e.g. "C=UK,O=ARM,CN=mbed TLS Server 1"
*
* \param ctx CRT context to use
* \param subject_name subject name to set
*
* \return 0 if subject name was parsed successfully, or
* a specific error code
*/
int mbedtls_x509write_crt_set_subject_name( mbedtls_x509write_cert *ctx,
const char *subject_name )
{
return mbedtls_x509_string_to_names( &ctx->subject, subject_name );
}
/**
* \brief Set the issuer name for a Certificate
* Issuer names should contain a comma-separated list
* of OID types and values:
* e.g. "C=UK,O=ARM,CN=mbed TLS CA"
*
* \param ctx CRT context to use
* \param issuer_name issuer name to set
*
* \return 0 if issuer name was parsed successfully, or
* a specific error code
*/
int mbedtls_x509write_crt_set_issuer_name( mbedtls_x509write_cert *ctx,
const char *issuer_name )
{
return mbedtls_x509_string_to_names( &ctx->issuer, issuer_name );
}
/**
* \brief Set the serial number for a Certificate.
*
* \param ctx CRT context to use
* \param serial serial number to set
*
* \return 0 if successful
*/
int mbedtls_x509write_crt_set_serial( mbedtls_x509write_cert *ctx,
const mbedtls_mpi *serial )
{
int ret = MBEDTLS_ERR_THIS_CORRUPTION;
if( ( ret = mbedtls_mpi_copy( &ctx->serial, serial ) ) != 0 )
return( ret );
return( 0 );
}
/**
* \brief Set the validity period for a Certificate
* Timestamps should be in string format for UTC timezone
* i.e. "YYYYMMDDhhmmss"
* e.g. "20131231235959" for December 31st 2013
* at 23:59:59
*
* \param ctx CRT context to use
* \param not_before not_before timestamp
* \param not_after not_after timestamp
*
* \return 0 if timestamp was parsed successfully, or
* a specific error code
*/
int mbedtls_x509write_crt_set_validity( mbedtls_x509write_cert *ctx,
const char *not_before,
const char *not_after )
{
if( strlen( not_before ) != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1 ||
strlen( not_after ) != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1 )
{
return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
}
strncpy( ctx->not_before, not_before, MBEDTLS_X509_RFC5280_UTC_TIME_LEN );
strncpy( ctx->not_after , not_after , MBEDTLS_X509_RFC5280_UTC_TIME_LEN );
ctx->not_before[MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1] = 'Z';
ctx->not_after[MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1] = 'Z';
return( 0 );
}
/**
* \brief Generic function to add to or replace an extension in the
* CRT
*
* \param ctx CRT context to use
* \param oid OID of the extension
* \param oid_len length of the OID
* \param critical if the extension is critical (per the RFC's definition)
* \param val value of the extension OCTET STRING
* \param val_len length of the value data
*
* \return 0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
*/
int mbedtls_x509write_crt_set_extension( mbedtls_x509write_cert *ctx,
const char *oid, size_t oid_len,
int critical, const unsigned char *val,
size_t val_len )
{
return( mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len,
critical, val, val_len ) );
}
/**
* \brief Set the basicConstraints extension for a CRT
*
* \param ctx CRT context to use
* \param is_ca is this a CA certificate
* \param max_pathlen maximum length of certificate chains below this
* certificate (only for CA certificates, -1 is
* inlimited)
*
* \return 0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
*/
int mbedtls_x509write_crt_set_basic_constraints( mbedtls_x509write_cert *ctx,
int is_ca, int max_pathlen )
{
int ret = MBEDTLS_ERR_THIS_CORRUPTION;
unsigned char buf[9];
unsigned char *c = buf + sizeof(buf);
size_t len = 0;
mbedtls_platform_zeroize( buf, sizeof(buf) );
if( is_ca && max_pathlen > 127 )
return( MBEDTLS_ERR_X509_BAD_INPUT_DATA );
if( is_ca )
{
if( max_pathlen >= 0 )
{
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf,
max_pathlen ) );
}
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_bool( &c, buf, 1 ) );
}
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf,
MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_ASN1_SEQUENCE ) );
return(
mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_BASIC_CONSTRAINTS,
MBEDTLS_OID_SIZE( MBEDTLS_OID_BASIC_CONSTRAINTS ),
is_ca, buf + sizeof(buf) - len, len ) );
}
#if defined(MBEDTLS_SHA1_C)
/**
* \brief Set the subjectKeyIdentifier extension for a CRT
* Requires that mbedtls_x509write_crt_set_subject_key() has been
* called before
*
* \param ctx CRT context to use
*
* \return 0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
*/
int mbedtls_x509write_crt_set_subject_key_identifier( mbedtls_x509write_cert *ctx )
{
int ret = MBEDTLS_ERR_THIS_CORRUPTION;
unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20]; /* tag, length + 2xMPI */
unsigned char *c = buf + sizeof(buf);
size_t len = 0;
mbedtls_platform_zeroize( buf, sizeof(buf) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_pk_write_pubkey( &c, buf, ctx->subject_key ) );
ret = mbedtls_sha1_ret( buf + sizeof( buf ) - len, len,
buf + sizeof( buf ) - 20 );
if( ret != 0 )
return( ret );
c = buf + sizeof( buf ) - 20;
len = 20;
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_OCTET_STRING ) );
return mbedtls_x509write_crt_set_extension( ctx,
MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER,
MBEDTLS_OID_SIZE( MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER ),
0, buf + sizeof(buf) - len, len );
}
/**
* \brief Set the authorityKeyIdentifier extension for a CRT
* Requires that mbedtls_x509write_crt_set_issuer_key() has been
* called before
*
* \param ctx CRT context to use
*
* \return 0 if successful, or a MBEDTLS_ERR_X509_ALLOC_FAILED
*/
int mbedtls_x509write_crt_set_authority_key_identifier( mbedtls_x509write_cert *ctx )
{
int ret = MBEDTLS_ERR_THIS_CORRUPTION;
unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20]; /* tag, length + 2xMPI */
unsigned char *c = buf + sizeof( buf );
size_t len = 0;
mbedtls_platform_zeroize( buf, sizeof(buf) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_pk_write_pubkey( &c, buf, ctx->issuer_key ) );
ret = mbedtls_sha1_ret( buf + sizeof( buf ) - len, len,
buf + sizeof( buf ) - 20 );
if( ret != 0 )
return( ret );
c = buf + sizeof( buf ) - 20;
len = 20;
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC | 0 ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag( &c, buf,
MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_ASN1_SEQUENCE ) );
return mbedtls_x509write_crt_set_extension(
ctx, MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER,
MBEDTLS_OID_SIZE( MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER ),
0, buf + sizeof( buf ) - len, len );
}
#endif /* MBEDTLS_SHA1_C */
/**
* \brief Set the Key Usage Extension flags
* (e.g. MBEDTLS_X509_KU_DIGITAL_SIGNATURE | MBEDTLS_X509_KU_KEY_CERT_SIGN)
*
* \param ctx CRT context to use
* \param key_usage key usage flags to set
*
* \return 0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
*/
int mbedtls_x509write_crt_set_key_usage( mbedtls_x509write_cert *ctx,
unsigned int key_usage )
{
unsigned char buf[5], ku[2];
unsigned char *c;
int ret = MBEDTLS_ERR_THIS_CORRUPTION;
const unsigned int allowed_bits = MBEDTLS_X509_KU_DIGITAL_SIGNATURE |
MBEDTLS_X509_KU_NON_REPUDIATION |
MBEDTLS_X509_KU_KEY_ENCIPHERMENT |
MBEDTLS_X509_KU_DATA_ENCIPHERMENT |
MBEDTLS_X509_KU_KEY_AGREEMENT |
MBEDTLS_X509_KU_KEY_CERT_SIGN |
MBEDTLS_X509_KU_CRL_SIGN |
MBEDTLS_X509_KU_ENCIPHER_ONLY |
MBEDTLS_X509_KU_DECIPHER_ONLY;
/* Check that nothing other than the allowed flags is set */
if( ( key_usage & ~allowed_bits ) != 0 )
return( MBEDTLS_ERR_X509_FEATURE_UNAVAILABLE );
c = buf + 5;
ku[0] = (unsigned char)( key_usage );
ku[1] = (unsigned char)( key_usage >> 8 );
ret = mbedtls_asn1_write_named_bitstring( &c, buf, ku, 9 );
if( ret < 0 )
return( ret );
else if( ret < 3 || ret > 5 )
return( MBEDTLS_ERR_X509_INVALID_FORMAT );
ret = mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_KEY_USAGE,
MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ),
1, c, (size_t)ret );
if( ret != 0 )
return( ret );
return( 0 );
}
/**
* \brief Set the Netscape Cert Type flags
* (e.g. MBEDTLS_X509_NS_CERT_TYPE_SSL_CLIENT | MBEDTLS_X509_NS_CERT_TYPE_EMAIL)
*
* \param ctx CRT context to use
* \param ns_cert_type Netscape Cert Type flags to set
*
* \return 0 if successful, or MBEDTLS_ERR_X509_ALLOC_FAILED
*/
int mbedtls_x509write_crt_set_ns_cert_type( mbedtls_x509write_cert *ctx,
unsigned char ns_cert_type )
{
unsigned char buf[4];
unsigned char *c;
int ret = MBEDTLS_ERR_THIS_CORRUPTION;
c = buf + 4;
ret = mbedtls_asn1_write_named_bitstring( &c, buf, &ns_cert_type, 8 );
if( ret < 3 || ret > 4 )
return( ret );
ret = mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE,
MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ),
0, c, (size_t)ret );
if( ret != 0 )
return( ret );
return( 0 );
}
/**
* Writes Extended Key Usage section to certificate.
*
* @see mbedtls_x509write_crt_set_ns_cert_type()
* @see RFC5280 §4.2.1.12
*/
int mbedtls_x509write_crt_set_ext_key_usage(mbedtls_x509write_cert *ctx,
int ns_cert_type) {
int ret;
size_t len;
unsigned char buf[256];
unsigned char *c;
if (!ns_cert_type) return 0;
if (ns_cert_type & ~(MBEDTLS_X509_NS_CERT_TYPE_SSL_CLIENT |
MBEDTLS_X509_NS_CERT_TYPE_SSL_SERVER |
MBEDTLS_X509_NS_CERT_TYPE_EMAIL)) {
return MBEDTLS_ERR_X509_BAD_INPUT_DATA;
}
len = 0;
c = buf + sizeof(buf);
mbedtls_platform_zeroize(buf, sizeof(buf));
if (ns_cert_type & MBEDTLS_X509_NS_CERT_TYPE_SSL_CLIENT) {
MBEDTLS_ASN1_CHK_ADD(
len, mbedtls_asn1_write_oid(&c, buf, MBEDTLS_OID_CLIENT_AUTH,
MBEDTLS_OID_SIZE(MBEDTLS_OID_CLIENT_AUTH)));
}
if (ns_cert_type & MBEDTLS_X509_NS_CERT_TYPE_SSL_SERVER) {
MBEDTLS_ASN1_CHK_ADD(
len, mbedtls_asn1_write_oid(&c, buf, MBEDTLS_OID_SERVER_AUTH,
MBEDTLS_OID_SIZE(MBEDTLS_OID_SERVER_AUTH)));
}
if (ns_cert_type & MBEDTLS_X509_NS_CERT_TYPE_EMAIL) {
MBEDTLS_ASN1_CHK_ADD(
len,
mbedtls_asn1_write_oid(&c, buf, MBEDTLS_OID_EMAIL_PROTECTION,
MBEDTLS_OID_SIZE(MBEDTLS_OID_EMAIL_PROTECTION)));
}
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, buf, len));
MBEDTLS_ASN1_CHK_ADD(
len, mbedtls_asn1_write_tag(
&c, buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));
return mbedtls_x509write_crt_set_extension(
ctx, MBEDTLS_OID_EXTENDED_KEY_USAGE,
MBEDTLS_OID_SIZE(MBEDTLS_OID_EXTENDED_KEY_USAGE), false,
buf + sizeof(buf) - len, len);
}
static int x509_write_time( unsigned char **p, unsigned char *start,
const char *t, size_t size )
{
int ret = MBEDTLS_ERR_THIS_CORRUPTION;
size_t len = 0;
/*
* write MBEDTLS_ASN1_UTC_TIME if year < 2050 (2 bytes shorter)
*/
if( t[0] == '2' && t[1] == '0' && t[2] < '5' )
{
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
(const unsigned char *) t + 2,
size - 2 ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
MBEDTLS_ASN1_UTC_TIME ) );
}
else
{
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
(const unsigned char *) t,
size ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
MBEDTLS_ASN1_GENERALIZED_TIME ) );
}
return( (int) len );
}
/**
* \brief Write a built up certificate to a X509 DER structure
* Note: data is written at the end of the buffer! Use the
* return value to determine where you should start
* using the buffer
*
* \param ctx certificate to write away
* \param buf buffer to write to
* \param size size of the buffer
* \param f_rng RNG function (for signature, see note)
* \param p_rng RNG parameter
*
* \return length of data written if successful, or a specific
* error code
*
* \note f_rng may be NULL if RSA is used for signature and the
* signature is made offline (otherwise f_rng is desirable
* for countermeasures against timing attacks).
* ECDSA signatures always require a non-NULL f_rng.
*/
int mbedtls_x509write_crt_der( mbedtls_x509write_cert *ctx,
unsigned char *buf, size_t size,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret = MBEDTLS_ERR_THIS_CORRUPTION;
const char *sig_oid;
size_t sig_oid_len = 0;
unsigned char *c, *c2;
unsigned char hash[64];
unsigned char sig[MBEDTLS_PK_SIGNATURE_MAX_SIZE];
size_t sub_len = 0, pub_len = 0, sig_and_oid_len = 0, sig_len;
size_t len = 0;
mbedtls_pk_type_t pk_alg;
/*
* Prepare data to be signed at the end of the target buffer
*/
c = buf + size;
/* Signature algorithm needed in TBS, and later for actual signature */
/* There's no direct way of extracting a signature algorithm
* (represented as an element of mbedtls_pk_type_t) from a PK instance. */
if( mbedtls_pk_can_do( ctx->issuer_key, MBEDTLS_PK_RSA ) )
pk_alg = MBEDTLS_PK_RSA;
else if( mbedtls_pk_can_do( ctx->issuer_key, MBEDTLS_PK_ECDSA ) )
pk_alg = MBEDTLS_PK_ECDSA;
else
return( MBEDTLS_ERR_X509_INVALID_ALG );
if( ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,
&sig_oid, &sig_oid_len ) ) != 0 )
{
return( ret );
}
/*
* Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension
*/
/* Only for v3 */
if( ctx->version == MBEDTLS_X509_CRT_VERSION_3 )
{
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_x509_write_extensions( &c,
buf, ctx->extensions ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag( &c, buf,
MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_ASN1_SEQUENCE ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag( &c, buf,
MBEDTLS_ASN1_CONTEXT_SPECIFIC |
MBEDTLS_ASN1_CONSTRUCTED | 3 ) );
}
/*
* SubjectPublicKeyInfo
*/
MBEDTLS_ASN1_CHK_ADD( pub_len,
mbedtls_pk_write_pubkey_der( ctx->subject_key,
buf, c - buf ) );
c -= pub_len;
len += pub_len;
/*
* Subject ::= Name
*/
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_x509_write_names( &c, buf,
ctx->subject ) );
/*
* Validity ::= SEQUENCE {
* notBefore Time,
* notAfter Time }
*/
sub_len = 0;
MBEDTLS_ASN1_CHK_ADD( sub_len,
x509_write_time( &c, buf, ctx->not_after,
MBEDTLS_X509_RFC5280_UTC_TIME_LEN ) );
MBEDTLS_ASN1_CHK_ADD( sub_len,
x509_write_time( &c, buf, ctx->not_before,
MBEDTLS_X509_RFC5280_UTC_TIME_LEN ) );
len += sub_len;
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, sub_len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag( &c, buf,
MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_ASN1_SEQUENCE ) );
/*
* Issuer ::= Name
*/
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, buf,
ctx->issuer ) );
/*
* Signature ::= AlgorithmIdentifier
*/
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_algorithm_identifier( &c, buf,
sig_oid, strlen( sig_oid ), 0 ) );
/*
* Serial ::= INTEGER
*/
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf,
&ctx->serial ) );
/*
* Version ::= INTEGER { v1(0), v2(1), v3(2) }
*/
/* Can be omitted for v1 */
if( ctx->version != MBEDTLS_X509_CRT_VERSION_1 )
{
sub_len = 0;
MBEDTLS_ASN1_CHK_ADD( sub_len,
mbedtls_asn1_write_int( &c, buf, ctx->version ) );
len += sub_len;
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_len( &c, buf, sub_len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag( &c, buf,
MBEDTLS_ASN1_CONTEXT_SPECIFIC |
MBEDTLS_ASN1_CONSTRUCTED | 0 ) );
}
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len,
mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_ASN1_SEQUENCE ) );
/*
* Make signature
*/
/* Compute hash of CRT. */
if( ( ret = mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c,
len, hash ) ) != 0 )
{
return( ret );
}
if( ( ret = mbedtls_pk_sign( ctx->issuer_key, ctx->md_alg,
hash, 0, sig, &sig_len,
f_rng, p_rng ) ) != 0 )
{
return( ret );
}
/* Move CRT to the front of the buffer to have space
* for the signature. */
memmove( buf, c, len );
c = buf + len;
/* Add signature at the end of the buffer,
* making sure that it doesn't underflow
* into the CRT buffer. */
c2 = buf + size;
MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, c,
sig_oid, sig_oid_len, sig, sig_len ) );
/*
* Memory layout after this step:
*
* buf c=buf+len c2 buf+size
* [CRT0,...,CRTn, UNUSED, ..., UNUSED, SIG0, ..., SIGm]
*/
/* Move raw CRT to just before the signature. */
c = c2 - len;
memmove( c, buf, len );
len += sig_and_oid_len;
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf,
MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_ASN1_SEQUENCE ) );
return( (int) len );
}
#define PEM_BEGIN_CRT "-----BEGIN CERTIFICATE-----\n"
#define PEM_END_CRT "-----END CERTIFICATE-----\n"
/**
* \brief Write a built up certificate to a X509 PEM string
*
* \param ctx certificate to write away
* \param buf buffer to write to
* \param size size of the buffer
* \param f_rng RNG function (for signature, see note)
* \param p_rng RNG parameter
*
* \return 0 if successful, or a specific error code
*
* \note f_rng may be NULL if RSA is used for signature and the
* signature is made offline (otherwise f_rng is desirable
* for countermeasures against timing attacks).
* ECDSA signatures always require a non-NULL f_rng.
*/
int mbedtls_x509write_crt_pem( mbedtls_x509write_cert *crt,
unsigned char *buf, size_t size,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng )
{
int ret = MBEDTLS_ERR_THIS_CORRUPTION;
size_t olen;
if( ( ret = mbedtls_x509write_crt_der( crt, buf, size,
f_rng, p_rng ) ) < 0 )
{
return( ret );
}
if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CRT, PEM_END_CRT,
buf + size - ret, ret,
buf, size, &olen ) ) != 0 )
{
return( ret );
}
return( 0 );
}
#endif /* MBEDTLS_X509_CRT_WRITE_C */
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