| /* |
| * 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 |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_X509_CRT_WRITE_C) |
| |
| #include "mbedtls/x509_crt.h" |
| #include "mbedtls/asn1write.h" |
| #include "mbedtls/error.h" |
| #include "mbedtls/oid.h" |
| #include "mbedtls/platform_util.h" |
| #include "mbedtls/sha1.h" |
| |
| #include <string.h> |
| |
| #if defined(MBEDTLS_PEM_WRITE_C) |
| #include "mbedtls/pem.h" |
| #endif /* MBEDTLS_PEM_WRITE_C */ |
| |
| void mbedtls_x509write_crt_init( mbedtls_x509write_cert *ctx ) |
| { |
| memset( ctx, 0, sizeof( mbedtls_x509write_cert ) ); |
| |
| mbedtls_mpi_init( &ctx->serial ); |
| ctx->version = MBEDTLS_X509_CRT_VERSION_3; |
| } |
| |
| 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 ) ); |
| } |
| |
| void mbedtls_x509write_crt_set_version( mbedtls_x509write_cert *ctx, |
| int version ) |
| { |
| ctx->version = version; |
| } |
| |
| void mbedtls_x509write_crt_set_md_alg( mbedtls_x509write_cert *ctx, |
| mbedtls_md_type_t md_alg ) |
| { |
| ctx->md_alg = md_alg; |
| } |
| |
| void mbedtls_x509write_crt_set_subject_key( mbedtls_x509write_cert *ctx, |
| mbedtls_pk_context *key ) |
| { |
| ctx->subject_key = key; |
| } |
| |
| void mbedtls_x509write_crt_set_issuer_key( mbedtls_x509write_cert *ctx, |
| mbedtls_pk_context *key ) |
| { |
| ctx->issuer_key = key; |
| } |
| |
| 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 ); |
| } |
| |
| 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 ); |
| } |
| |
| int mbedtls_x509write_crt_set_serial( mbedtls_x509write_cert *ctx, |
| const mbedtls_mpi *serial ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| if( ( ret = mbedtls_mpi_copy( &ctx->serial, serial ) ) != 0 ) |
| return( ret ); |
| |
| return( 0 ); |
| } |
| |
| 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 ); |
| } |
| |
| 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 ) ); |
| } |
| |
| int mbedtls_x509write_crt_set_basic_constraints( mbedtls_x509write_cert *ctx, |
| int is_ca, int max_pathlen ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char buf[9]; |
| unsigned char *c = buf + sizeof(buf); |
| size_t len = 0; |
| |
| memset( buf, 0, 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) |
| int mbedtls_x509write_crt_set_subject_key_identifier( mbedtls_x509write_cert *ctx ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20]; /* tag, length + 2xMPI */ |
| unsigned char *c = buf + sizeof(buf); |
| size_t len = 0; |
| |
| memset( buf, 0, 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 ); |
| } |
| |
| int mbedtls_x509write_crt_set_authority_key_identifier( mbedtls_x509write_cert *ctx ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20]; /* tag, length + 2xMPI */ |
| unsigned char *c = buf + sizeof( buf ); |
| size_t len = 0; |
| |
| memset( buf, 0, 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 */ |
| |
| int mbedtls_x509write_crt_set_key_usage( mbedtls_x509write_cert *ctx, |
| unsigned int key_usage ) |
| { |
| unsigned char buf[5] = {0}, ku[2] = {0}; |
| unsigned char *c; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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 ); |
| } |
| |
| int mbedtls_x509write_crt_set_ns_cert_type( mbedtls_x509write_cert *ctx, |
| unsigned char ns_cert_type ) |
| { |
| unsigned char buf[4] = {0}; |
| unsigned char *c; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| 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 ); |
| } |
| |
| static int x509_write_time( unsigned char **p, unsigned char *start, |
| const char *t, size_t size ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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 ); |
| } |
| |
| 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_ERROR_CORRUPTION_DETECTED; |
| 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" |
| |
| #if defined(MBEDTLS_PEM_WRITE_C) |
| 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_ERROR_CORRUPTION_DETECTED; |
| 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_PEM_WRITE_C */ |
| |
| #endif /* MBEDTLS_X509_CRT_WRITE_C */ |
