diff options
Diffstat (limited to 'library/x509write_csr.c')
| -rw-r--r-- | library/x509write_csr.c | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/library/x509write_csr.c b/library/x509write_csr.c new file mode 100644 index 000000000..976f6e6df --- /dev/null +++ b/library/x509write_csr.c @@ -0,0 +1,337 @@ +/* + * X.509 Certificate Signing Request 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: + * - CSRs: PKCS#10 v1.7 aka RFC 2986 + * - attributes: PKCS#9 v2.0 aka RFC 2985 + */ + +#include "common.h" + +#if defined(MBEDTLS_X509_CSR_WRITE_C) + +#include "mbedtls/x509_csr.h" +#include "mbedtls/asn1write.h" +#include "mbedtls/error.h" +#include "mbedtls/oid.h" +#include "mbedtls/platform_util.h" + +#if defined(MBEDTLS_USE_PSA_CRYPTO) +#include "psa/crypto.h" +#include "mbedtls/psa_util.h" +#endif /* MBEDTLS_USE_PSA_CRYPTO */ +#include "hash_info.h" + +#include <string.h> +#include <stdlib.h> + +#if defined(MBEDTLS_PEM_WRITE_C) +#include "mbedtls/pem.h" +#endif + +#include "mbedtls/platform.h" + +void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx ) +{ + memset( ctx, 0, sizeof( mbedtls_x509write_csr ) ); +} + +void mbedtls_x509write_csr_free( mbedtls_x509write_csr *ctx ) +{ + mbedtls_asn1_free_named_data_list( &ctx->subject ); + mbedtls_asn1_free_named_data_list( &ctx->extensions ); + + mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x509write_csr ) ); +} + +void mbedtls_x509write_csr_set_md_alg( mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg ) +{ + ctx->md_alg = md_alg; +} + +void mbedtls_x509write_csr_set_key( mbedtls_x509write_csr *ctx, mbedtls_pk_context *key ) +{ + ctx->key = key; +} + +int mbedtls_x509write_csr_set_subject_name( mbedtls_x509write_csr *ctx, + const char *subject_name ) +{ + return mbedtls_x509_string_to_names( &ctx->subject, subject_name ); +} + +int mbedtls_x509write_csr_set_extension( mbedtls_x509write_csr *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_csr_set_key_usage( mbedtls_x509write_csr *ctx, unsigned char key_usage ) +{ + 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, &key_usage, 8 ); + if( ret < 3 || ret > 4 ) + return( ret ); + + ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_KEY_USAGE, + MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ), + 0, c, (size_t)ret ); + if( ret != 0 ) + return( ret ); + + return( 0 ); +} + +int mbedtls_x509write_csr_set_ns_cert_type( mbedtls_x509write_csr *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_csr_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 x509write_csr_der_internal( mbedtls_x509write_csr *ctx, + unsigned char *buf, + size_t size, + unsigned char *sig, size_t sig_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[MBEDTLS_HASH_MAX_SIZE]; + size_t pub_len = 0, sig_and_oid_len = 0, sig_len; + size_t len = 0; + mbedtls_pk_type_t pk_alg; +#if defined(MBEDTLS_USE_PSA_CRYPTO) + size_t hash_len; + psa_algorithm_t hash_alg = mbedtls_hash_info_psa_from_md( ctx->md_alg ); +#endif /* MBEDTLS_USE_PSA_CRYPTO */ + + /* Write the CSR backwards starting from the end of buf */ + c = buf + size; + + MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, buf, + ctx->extensions ) ); + + if( 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 ) ); + + 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_SET ) ); + + MBEDTLS_ASN1_CHK_ADD( len, + mbedtls_asn1_write_oid( + &c, buf, MBEDTLS_OID_PKCS9_CSR_EXT_REQ, + MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS9_CSR_EXT_REQ ) ) ); + + 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_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC ) ); + + MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->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 ) ); + + /* + * Version ::= INTEGER { v1(0), v2(1), v3(2) } + */ + MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, 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 ) ); + + /* + * Sign the written CSR data into the sig buffer + * Note: hash errors can happen only after an internal error + */ +#if defined(MBEDTLS_USE_PSA_CRYPTO) + if( psa_hash_compute( hash_alg, + c, + len, + hash, + sizeof( hash ), + &hash_len ) != PSA_SUCCESS ) + { + return( MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED ); + } +#else /* MBEDTLS_USE_PSA_CRYPTO */ + ret = mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash ); + if( ret != 0 ) + return( ret ); +#endif + if( ( ret = mbedtls_pk_sign( ctx->key, ctx->md_alg, hash, 0, + sig, sig_size, &sig_len, + f_rng, p_rng ) ) != 0 ) + { + return( ret ); + } + + if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_RSA ) ) + pk_alg = MBEDTLS_PK_RSA; + else if( mbedtls_pk_can_do( ctx->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 ); + } + + /* + * Move the written CSR data to the start of buf to create space for + * writing the signature into buf. + */ + memmove( buf, c, len ); + + /* + * Write sig and its OID into buf backwards from the end of buf. + * Note: mbedtls_x509_write_sig will check for c2 - ( buf + len ) < sig_len + * and return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL if needed. + */ + c2 = buf + size; + MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, + mbedtls_x509_write_sig( &c2, buf + len, sig_oid, sig_oid_len, + sig, sig_len ) ); + + /* + * Compact the space between the CSR data and signature by moving the + * CSR data to the start of the signature. + */ + c2 -= len; + memmove( c2, buf, len ); + + /* ASN encode the total size and tag the CSR data with it. */ + len += sig_and_oid_len; + MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) ); + MBEDTLS_ASN1_CHK_ADD( len, + mbedtls_asn1_write_tag( + &c2, buf, + MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ); + + /* Zero the unused bytes at the start of buf */ + memset( buf, 0, c2 - buf); + + return( (int) len ); +} + +int mbedtls_x509write_csr_der( mbedtls_x509write_csr *ctx, unsigned char *buf, + size_t size, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng ) +{ + int ret; + unsigned char *sig; + + if( ( sig = mbedtls_calloc( 1, MBEDTLS_PK_SIGNATURE_MAX_SIZE ) ) == NULL ) + { + return( MBEDTLS_ERR_X509_ALLOC_FAILED ); + } + + ret = x509write_csr_der_internal( ctx, buf, size, + sig, MBEDTLS_PK_SIGNATURE_MAX_SIZE, + f_rng, p_rng ); + + mbedtls_free( sig ); + + return( ret ); +} + +#define PEM_BEGIN_CSR "-----BEGIN CERTIFICATE REQUEST-----\n" +#define PEM_END_CSR "-----END CERTIFICATE REQUEST-----\n" + +#if defined(MBEDTLS_PEM_WRITE_C) +int mbedtls_x509write_csr_pem( mbedtls_x509write_csr *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; + size_t olen = 0; + + if( ( ret = mbedtls_x509write_csr_der( ctx, buf, size, + f_rng, p_rng ) ) < 0 ) + { + return( ret ); + } + + if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR, + buf + size - ret, + ret, buf, size, &olen ) ) != 0 ) + { + return( ret ); + } + + return( 0 ); +} +#endif /* MBEDTLS_PEM_WRITE_C */ + +#endif /* MBEDTLS_X509_CSR_WRITE_C */ |