1 /* 2 * X.509 Certificate Signing Request writing 3 * 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 5 * SPDX-License-Identifier: Apache-2.0 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 39 #include <string.h> 40 #include <stdlib.h> 41 42 #if defined(MBEDTLS_PEM_WRITE_C) 43 #include "mbedtls/pem.h" 44 #endif 45 46 /* Implementation that should never be optimized out by the compiler */ 47 static void mbedtls_zeroize( void *v, size_t n ) { 48 volatile unsigned char *p = v; while( n-- ) *p++ = 0; 49 } 50 51 void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx ) 52 { 53 memset( ctx, 0, sizeof(mbedtls_x509write_csr) ); 54 } 55 56 void mbedtls_x509write_csr_free( mbedtls_x509write_csr *ctx ) 57 { 58 mbedtls_asn1_free_named_data_list( &ctx->subject ); 59 mbedtls_asn1_free_named_data_list( &ctx->extensions ); 60 61 mbedtls_zeroize( ctx, sizeof(mbedtls_x509write_csr) ); 62 } 63 64 void mbedtls_x509write_csr_set_md_alg( mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg ) 65 { 66 ctx->md_alg = md_alg; 67 } 68 69 void mbedtls_x509write_csr_set_key( mbedtls_x509write_csr *ctx, mbedtls_pk_context *key ) 70 { 71 ctx->key = key; 72 } 73 74 int mbedtls_x509write_csr_set_subject_name( mbedtls_x509write_csr *ctx, 75 const char *subject_name ) 76 { 77 return mbedtls_x509_string_to_names( &ctx->subject, subject_name ); 78 } 79 80 int mbedtls_x509write_csr_set_extension( mbedtls_x509write_csr *ctx, 81 const char *oid, size_t oid_len, 82 const unsigned char *val, size_t val_len ) 83 { 84 return mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len, 85 0, val, val_len ); 86 } 87 88 int mbedtls_x509write_csr_set_key_usage( mbedtls_x509write_csr *ctx, unsigned char key_usage ) 89 { 90 unsigned char buf[4]; 91 unsigned char *c; 92 int ret; 93 94 c = buf + 4; 95 96 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &key_usage, 7 ) ) != 4 ) 97 return( ret ); 98 99 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_KEY_USAGE, 100 MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ), 101 buf, 4 ); 102 if( ret != 0 ) 103 return( ret ); 104 105 return( 0 ); 106 } 107 108 int mbedtls_x509write_csr_set_ns_cert_type( mbedtls_x509write_csr *ctx, 109 unsigned char ns_cert_type ) 110 { 111 unsigned char buf[4]; 112 unsigned char *c; 113 int ret; 114 115 c = buf + 4; 116 117 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &ns_cert_type, 8 ) ) != 4 ) 118 return( ret ); 119 120 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE, 121 MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ), 122 buf, 4 ); 123 if( ret != 0 ) 124 return( ret ); 125 126 return( 0 ); 127 } 128 129 int mbedtls_x509write_csr_der( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size, 130 int (*f_rng)(void *, unsigned char *, size_t), 131 void *p_rng ) 132 { 133 int ret; 134 const char *sig_oid; 135 size_t sig_oid_len = 0; 136 unsigned char *c, *c2; 137 unsigned char hash[64]; 138 unsigned char sig[MBEDTLS_MPI_MAX_SIZE]; 139 unsigned char tmp_buf[2048]; 140 size_t pub_len = 0, sig_and_oid_len = 0, sig_len; 141 size_t len = 0; 142 mbedtls_pk_type_t pk_alg; 143 144 /* 145 * Prepare data to be signed in tmp_buf 146 */ 147 c = tmp_buf + sizeof( tmp_buf ); 148 149 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) ); 150 151 if( len ) 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_SEQUENCE ) ); 156 157 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 158 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 159 MBEDTLS_ASN1_SET ) ); 160 161 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( &c, tmp_buf, MBEDTLS_OID_PKCS9_CSR_EXT_REQ, 162 MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS9_CSR_EXT_REQ ) ) ); 163 164 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 165 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 166 MBEDTLS_ASN1_SEQUENCE ) ); 167 } 168 169 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 170 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 171 MBEDTLS_ASN1_CONTEXT_SPECIFIC ) ); 172 173 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->key, 174 tmp_buf, c - tmp_buf ) ); 175 c -= pub_len; 176 len += pub_len; 177 178 /* 179 * Subject ::= Name 180 */ 181 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->subject ) ); 182 183 /* 184 * Version ::= INTEGER { v1(0), v2(1), v3(2) } 185 */ 186 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, tmp_buf, 0 ) ); 187 188 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 189 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 190 MBEDTLS_ASN1_SEQUENCE ) ); 191 192 /* 193 * Prepare signature 194 */ 195 mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash ); 196 197 pk_alg = mbedtls_pk_get_type( ctx->key ); 198 if( pk_alg == MBEDTLS_PK_ECKEY ) 199 pk_alg = MBEDTLS_PK_ECDSA; 200 201 if( ( ret = mbedtls_pk_sign( ctx->key, ctx->md_alg, hash, 0, sig, &sig_len, 202 f_rng, p_rng ) ) != 0 || 203 ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg, 204 &sig_oid, &sig_oid_len ) ) != 0 ) 205 { 206 return( ret ); 207 } 208 209 /* 210 * Write data to output buffer 211 */ 212 c2 = buf + size; 213 MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, buf, 214 sig_oid, sig_oid_len, sig, sig_len ) ); 215 216 if( len > (size_t)( c2 - buf ) ) 217 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 218 219 c2 -= len; 220 memcpy( c2, c, len ); 221 222 len += sig_and_oid_len; 223 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) ); 224 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c2, buf, MBEDTLS_ASN1_CONSTRUCTED | 225 MBEDTLS_ASN1_SEQUENCE ) ); 226 227 return( (int) len ); 228 } 229 230 #define PEM_BEGIN_CSR "-----BEGIN CERTIFICATE REQUEST-----\n" 231 #define PEM_END_CSR "-----END CERTIFICATE REQUEST-----\n" 232 233 #if defined(MBEDTLS_PEM_WRITE_C) 234 int mbedtls_x509write_csr_pem( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size, 235 int (*f_rng)(void *, unsigned char *, size_t), 236 void *p_rng ) 237 { 238 int ret; 239 unsigned char output_buf[4096]; 240 size_t olen = 0; 241 242 if( ( ret = mbedtls_x509write_csr_der( ctx, output_buf, sizeof(output_buf), 243 f_rng, p_rng ) ) < 0 ) 244 { 245 return( ret ); 246 } 247 248 if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR, 249 output_buf + sizeof(output_buf) - ret, 250 ret, buf, size, &olen ) ) != 0 ) 251 { 252 return( ret ); 253 } 254 255 return( 0 ); 256 } 257 #endif /* MBEDTLS_PEM_WRITE_C */ 258 259 #endif /* MBEDTLS_X509_CSR_WRITE_C */ 260