1 /* 2 * X.509 Certificate Signing Request writing 3 * 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 5 * SPDX-License-Identifier: GPL-2.0 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License along 18 * with this program; if not, write to the Free Software Foundation, Inc., 19 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * This file is part of mbed TLS (https://tls.mbed.org) 22 */ 23 /* 24 * References: 25 * - CSRs: PKCS#10 v1.7 aka RFC 2986 26 * - attributes: PKCS#9 v2.0 aka RFC 2985 27 */ 28 29 #if !defined(MBEDTLS_CONFIG_FILE) 30 #include "mbedtls/config.h" 31 #else 32 #include MBEDTLS_CONFIG_FILE 33 #endif 34 35 #if defined(MBEDTLS_X509_CSR_WRITE_C) 36 37 #include "mbedtls/x509_csr.h" 38 #include "mbedtls/oid.h" 39 #include "mbedtls/asn1write.h" 40 41 #include <string.h> 42 #include <stdlib.h> 43 44 #if defined(MBEDTLS_PEM_WRITE_C) 45 #include "mbedtls/pem.h" 46 #endif 47 48 /* Implementation that should never be optimized out by the compiler */ 49 static void mbedtls_zeroize( void *v, size_t n ) { 50 volatile unsigned char *p = v; while( n-- ) *p++ = 0; 51 } 52 53 void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx ) 54 { 55 memset( ctx, 0, sizeof( mbedtls_x509write_csr ) ); 56 } 57 58 void mbedtls_x509write_csr_free( mbedtls_x509write_csr *ctx ) 59 { 60 mbedtls_asn1_free_named_data_list( &ctx->subject ); 61 mbedtls_asn1_free_named_data_list( &ctx->extensions ); 62 63 mbedtls_zeroize( ctx, sizeof( mbedtls_x509write_csr ) ); 64 } 65 66 void mbedtls_x509write_csr_set_md_alg( mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg ) 67 { 68 ctx->md_alg = md_alg; 69 } 70 71 void mbedtls_x509write_csr_set_key( mbedtls_x509write_csr *ctx, mbedtls_pk_context *key ) 72 { 73 ctx->key = key; 74 } 75 76 int mbedtls_x509write_csr_set_subject_name( mbedtls_x509write_csr *ctx, 77 const char *subject_name ) 78 { 79 return mbedtls_x509_string_to_names( &ctx->subject, subject_name ); 80 } 81 82 int mbedtls_x509write_csr_set_extension( mbedtls_x509write_csr *ctx, 83 const char *oid, size_t oid_len, 84 const unsigned char *val, size_t val_len ) 85 { 86 return mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len, 87 0, val, val_len ); 88 } 89 90 int mbedtls_x509write_csr_set_key_usage( mbedtls_x509write_csr *ctx, unsigned char key_usage ) 91 { 92 unsigned char buf[4]; 93 unsigned char *c; 94 int ret; 95 96 c = buf + 4; 97 98 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &key_usage, 7 ) ) != 4 ) 99 return( ret ); 100 101 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_KEY_USAGE, 102 MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ), 103 buf, 4 ); 104 if( ret != 0 ) 105 return( ret ); 106 107 return( 0 ); 108 } 109 110 int mbedtls_x509write_csr_set_ns_cert_type( mbedtls_x509write_csr *ctx, 111 unsigned char ns_cert_type ) 112 { 113 unsigned char buf[4]; 114 unsigned char *c; 115 int ret; 116 117 c = buf + 4; 118 119 if( ( ret = mbedtls_asn1_write_bitstring( &c, buf, &ns_cert_type, 8 ) ) != 4 ) 120 return( ret ); 121 122 ret = mbedtls_x509write_csr_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE, 123 MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ), 124 buf, 4 ); 125 if( ret != 0 ) 126 return( ret ); 127 128 return( 0 ); 129 } 130 131 int mbedtls_x509write_csr_der( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size, 132 int (*f_rng)(void *, unsigned char *, size_t), 133 void *p_rng ) 134 { 135 int ret; 136 const char *sig_oid; 137 size_t sig_oid_len = 0; 138 unsigned char *c, *c2; 139 unsigned char hash[64]; 140 unsigned char sig[MBEDTLS_MPI_MAX_SIZE]; 141 unsigned char tmp_buf[2048]; 142 size_t pub_len = 0, sig_and_oid_len = 0, sig_len; 143 size_t len = 0; 144 mbedtls_pk_type_t pk_alg; 145 146 /* 147 * Prepare data to be signed in tmp_buf 148 */ 149 c = tmp_buf + sizeof( tmp_buf ); 150 151 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) ); 152 153 if( len ) 154 { 155 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 156 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 157 MBEDTLS_ASN1_SEQUENCE ) ); 158 159 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 160 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 161 MBEDTLS_ASN1_SET ) ); 162 163 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( &c, tmp_buf, MBEDTLS_OID_PKCS9_CSR_EXT_REQ, 164 MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS9_CSR_EXT_REQ ) ) ); 165 166 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 167 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 168 MBEDTLS_ASN1_SEQUENCE ) ); 169 } 170 171 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 172 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 173 MBEDTLS_ASN1_CONTEXT_SPECIFIC ) ); 174 175 MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->key, 176 tmp_buf, c - tmp_buf ) ); 177 c -= pub_len; 178 len += pub_len; 179 180 /* 181 * Subject ::= Name 182 */ 183 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->subject ) ); 184 185 /* 186 * Version ::= INTEGER { v1(0), v2(1), v3(2) } 187 */ 188 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, tmp_buf, 0 ) ); 189 190 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) ); 191 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | 192 MBEDTLS_ASN1_SEQUENCE ) ); 193 194 /* 195 * Prepare signature 196 */ 197 mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash ); 198 199 if( ( ret = mbedtls_pk_sign( ctx->key, ctx->md_alg, hash, 0, sig, &sig_len, 200 f_rng, p_rng ) ) != 0 ) 201 { 202 return( ret ); 203 } 204 205 if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_RSA ) ) 206 pk_alg = MBEDTLS_PK_RSA; 207 else if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_ECDSA ) ) 208 pk_alg = MBEDTLS_PK_ECDSA; 209 else 210 return( MBEDTLS_ERR_X509_INVALID_ALG ); 211 212 if( ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg, 213 &sig_oid, &sig_oid_len ) ) != 0 ) 214 { 215 return( ret ); 216 } 217 218 /* 219 * Write data to output buffer 220 */ 221 c2 = buf + size; 222 MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, buf, 223 sig_oid, sig_oid_len, sig, sig_len ) ); 224 225 if( len > (size_t)( c2 - buf ) ) 226 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 227 228 c2 -= len; 229 memcpy( c2, c, len ); 230 231 len += sig_and_oid_len; 232 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) ); 233 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c2, buf, MBEDTLS_ASN1_CONSTRUCTED | 234 MBEDTLS_ASN1_SEQUENCE ) ); 235 236 return( (int) len ); 237 } 238 239 #define PEM_BEGIN_CSR "-----BEGIN CERTIFICATE REQUEST-----\n" 240 #define PEM_END_CSR "-----END CERTIFICATE REQUEST-----\n" 241 242 #if defined(MBEDTLS_PEM_WRITE_C) 243 int mbedtls_x509write_csr_pem( mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size, 244 int (*f_rng)(void *, unsigned char *, size_t), 245 void *p_rng ) 246 { 247 int ret; 248 unsigned char output_buf[4096]; 249 size_t olen = 0; 250 251 if( ( ret = mbedtls_x509write_csr_der( ctx, output_buf, sizeof(output_buf), 252 f_rng, p_rng ) ) < 0 ) 253 { 254 return( ret ); 255 } 256 257 if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR, 258 output_buf + sizeof(output_buf) - ret, 259 ret, buf, size, &olen ) ) != 0 ) 260 { 261 return( ret ); 262 } 263 264 return( 0 ); 265 } 266 #endif /* MBEDTLS_PEM_WRITE_C */ 267 268 #endif /* MBEDTLS_X509_CSR_WRITE_C */ 269