1 // SPDX-License-Identifier: Apache-2.0 2 /* 3 * X.509 Certificate Signing Request writing 4 * 5 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 6 * 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may 8 * not use this file except in compliance with the License. 9 * You may obtain a copy of the License at 10 * 11 * http://www.apache.org/licenses/LICENSE-2.0 12 * 13 * Unless required by applicable law or agreed to in writing, software 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 * See the License for the specific language governing permissions and 17 * limitations under the License. 18 * 19 * This file is part of mbed TLS (https://tls.mbed.org) 20 */ 21 /* 22 * References: 23 * - CSRs: PKCS#10 v1.7 aka RFC 2986 24 * - attributes: PKCS#9 v2.0 aka RFC 2985 25 */ 26 27 #if !defined(MBEDTLS_CONFIG_FILE) 28 #include "mbedtls/config.h" 29 #else 30 #include MBEDTLS_CONFIG_FILE 31 #endif 32 33 #if defined(MBEDTLS_X509_CSR_WRITE_C) 34 35 #include "mbedtls/x509_csr.h" 36 #include "mbedtls/oid.h" 37 #include "mbedtls/asn1write.h" 38 #include "mbedtls/platform_util.h" 39 40 #include <string.h> 41 #include <stdlib.h> 42 43 #if defined(MBEDTLS_PEM_WRITE_C) 44 #include "mbedtls/pem.h" 45 #endif 46 47 void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx ) 48 { 49 memset( ctx, 0, sizeof( mbedtls_x509write_csr ) ); 50 } 51 52 void mbedtls_x509write_csr_free( mbedtls_x509write_csr *ctx ) 53 { 54 mbedtls_asn1_free_named_data_list( &ctx->subject ); 55 mbedtls_asn1_free_named_data_list( &ctx->extensions ); 56 57 mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x509write_csr ) ); 58 } 59 60 void mbedtls_x509write_csr_set_md_alg( mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg ) 61 { 62 ctx->md_alg = md_alg; 63 } 64 65 void mbedtls_x509write_csr_set_key( mbedtls_x509write_csr *ctx, mbedtls_pk_context *key ) 66 { 67 ctx->key = key; 68 } 69 70 int mbedtls_x509write_csr_set_subject_name( mbedtls_x509write_csr *ctx, 71 const char *subject_name ) 72 { 73 return mbedtls_x509_string_to_names( &ctx->subject, subject_name ); 74 } 75 76 int mbedtls_x509write_csr_set_extension( mbedtls_x509write_csr *ctx, 77 const char *oid, size_t oid_len, 78 const unsigned char *val, size_t val_len ) 79 { 80 return mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len, 81 0, val, val_len ); 82 } 83 84 int mbedtls_x509write_csr_set_key_usage( mbedtls_x509write_csr *ctx, unsigned char key_usage ) 85 { 86 unsigned char buf[4]; 87 unsigned char *c; 88 int ret; 89 90 c = buf + 4; 91 92 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &key_usage, 7 ) ) != 4 ) 93 return( ret ); 94 95 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_KEY_USAGE, 96 MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ), 97 buf, 4 ); 98 if( ret != 0 ) 99 return( ret ); 100 101 return( 0 ); 102 } 103 104 int mbedtls_x509write_csr_set_ns_cert_type( mbedtls_x509write_csr *ctx, 105 unsigned char ns_cert_type ) 106 { 107 unsigned char buf[4]; 108 unsigned char *c; 109 int ret; 110 111 c = buf + 4; 112 113 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &ns_cert_type, 8 ) ) != 4 ) 114 return( ret ); 115 116 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE, 117 MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ), 118 buf, 4 ); 119 if( ret != 0 ) 120 return( ret ); 121 122 return( 0 ); 123 } 124 125 int mbedtls_x509write_csr_der( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size, 126 int (*f_rng)(void *, unsigned char *, size_t), 127 void *p_rng ) 128 { 129 int ret; 130 const char *sig_oid; 131 size_t sig_oid_len = 0; 132 unsigned char *c, *c2; 133 unsigned char hash[64]; 134 unsigned char sig[MBEDTLS_MPI_MAX_SIZE]; 135 unsigned char tmp_buf[2048]; 136 size_t pub_len = 0, sig_and_oid_len = 0, sig_len; 137 size_t len = 0; 138 mbedtls_pk_type_t pk_alg; 139 140 /* 141 * Prepare data to be signed in tmp_buf 142 */ 143 c = tmp_buf + sizeof( tmp_buf ); 144 145 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) ); 146 147 if( len ) 148 { 149 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 150 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 151 MBEDTLS_ASN1_SEQUENCE ) ); 152 153 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 154 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 155 MBEDTLS_ASN1_SET ) ); 156 157 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( &c, tmp_buf, MBEDTLS_OID_PKCS9_CSR_EXT_REQ, 158 MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS9_CSR_EXT_REQ ) ) ); 159 160 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 161 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 162 MBEDTLS_ASN1_SEQUENCE ) ); 163 } 164 165 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 166 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 167 MBEDTLS_ASN1_CONTEXT_SPECIFIC ) ); 168 169 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->key, 170 tmp_buf, c - tmp_buf ) ); 171 c -= pub_len; 172 len += pub_len; 173 174 /* 175 * Subject ::= Name 176 */ 177 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->subject ) ); 178 179 /* 180 * Version ::= INTEGER { v1(0), v2(1), v3(2) } 181 */ 182 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, tmp_buf, 0 ) ); 183 184 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 185 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 186 MBEDTLS_ASN1_SEQUENCE ) ); 187 188 /* 189 * Prepare signature 190 */ 191 mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash ); 192 193 if( ( ret = mbedtls_pk_sign( ctx->key, ctx->md_alg, hash, 0, sig, &sig_len, 194 f_rng, p_rng ) ) != 0 ) 195 { 196 return( ret ); 197 } 198 199 if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_RSA ) ) 200 pk_alg = MBEDTLS_PK_RSA; 201 else if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_ECDSA ) ) 202 pk_alg = MBEDTLS_PK_ECDSA; 203 else 204 return( MBEDTLS_ERR_X509_INVALID_ALG ); 205 206 if( ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg, 207 &sig_oid, &sig_oid_len ) ) != 0 ) 208 { 209 return( ret ); 210 } 211 212 /* 213 * Write data to output buffer 214 */ 215 c2 = buf + size; 216 MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, buf, 217 sig_oid, sig_oid_len, sig, sig_len ) ); 218 219 if( len > (size_t)( c2 - buf ) ) 220 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 221 222 c2 -= len; 223 memcpy( c2, c, len ); 224 225 len += sig_and_oid_len; 226 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) ); 227 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c2, buf, MBEDTLS_ASN1_CONSTRUCTED | 228 MBEDTLS_ASN1_SEQUENCE ) ); 229 230 return( (int) len ); 231 } 232 233 #define PEM_BEGIN_CSR "-----BEGIN CERTIFICATE REQUEST-----\n" 234 #define PEM_END_CSR "-----END CERTIFICATE REQUEST-----\n" 235 236 #if defined(MBEDTLS_PEM_WRITE_C) 237 int mbedtls_x509write_csr_pem( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size, 238 int (*f_rng)(void *, unsigned char *, size_t), 239 void *p_rng ) 240 { 241 int ret; 242 unsigned char output_buf[4096]; 243 size_t olen = 0; 244 245 if( ( ret = mbedtls_x509write_csr_der( ctx, output_buf, sizeof(output_buf), 246 f_rng, p_rng ) ) < 0 ) 247 { 248 return( ret ); 249 } 250 251 if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR, 252 output_buf + sizeof(output_buf) - ret, 253 ret, buf, size, &olen ) ) != 0 ) 254 { 255 return( ret ); 256 } 257 258 return( 0 ); 259 } 260 #endif /* MBEDTLS_PEM_WRITE_C */ 261 262 #endif /* MBEDTLS_X509_CSR_WRITE_C */ 263