1 /* 2 * X.509 Certificate Signing Request (CSR) parsing 3 * 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 6 * 7 * This file is provided under the Apache License 2.0, or the 8 * GNU General Public License v2.0 or later. 9 * 10 * ********** 11 * Apache License 2.0: 12 * 13 * Licensed under the Apache License, Version 2.0 (the "License"); you may 14 * not use this file except in compliance with the License. 15 * You may obtain a copy of the License at 16 * 17 * http://www.apache.org/licenses/LICENSE-2.0 18 * 19 * Unless required by applicable law or agreed to in writing, software 20 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 21 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 22 * See the License for the specific language governing permissions and 23 * limitations under the License. 24 * 25 * ********** 26 * 27 * ********** 28 * GNU General Public License v2.0 or later: 29 * 30 * This program is free software; you can redistribute it and/or modify 31 * it under the terms of the GNU General Public License as published by 32 * the Free Software Foundation; either version 2 of the License, or 33 * (at your option) any later version. 34 * 35 * This program is distributed in the hope that it will be useful, 36 * but WITHOUT ANY WARRANTY; without even the implied warranty of 37 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 38 * GNU General Public License for more details. 39 * 40 * You should have received a copy of the GNU General Public License along 41 * with this program; if not, write to the Free Software Foundation, Inc., 42 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 43 * 44 * ********** 45 * 46 * This file is part of mbed TLS (https://tls.mbed.org) 47 */ 48 /* 49 * The ITU-T X.509 standard defines a certificate format for PKI. 50 * 51 * http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs) 52 * http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs) 53 * http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10) 54 * 55 * http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf 56 * http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf 57 */ 58 59 #if !defined(MBEDTLS_CONFIG_FILE) 60 #include "mbedtls/config.h" 61 #else 62 #include MBEDTLS_CONFIG_FILE 63 #endif 64 65 #if defined(MBEDTLS_X509_CSR_PARSE_C) 66 67 #include "mbedtls/x509_csr.h" 68 #include "mbedtls/oid.h" 69 70 #include <string.h> 71 72 #if defined(MBEDTLS_PEM_PARSE_C) 73 #include "mbedtls/pem.h" 74 #endif 75 76 #if defined(MBEDTLS_PLATFORM_C) 77 #include "mbedtls/platform.h" 78 #else 79 #include <stdlib.h> 80 #include <stdio.h> 81 #define mbedtls_free free 82 #define mbedtls_calloc calloc 83 #define mbedtls_snprintf snprintf 84 #endif 85 86 #if defined(MBEDTLS_FS_IO) || defined(EFIX64) || defined(EFI32) 87 #include <stdio.h> 88 #endif 89 90 /* Implementation that should never be optimized out by the compiler */ 91 static void mbedtls_zeroize( void *v, size_t n ) { 92 volatile unsigned char *p = v; while( n-- ) *p++ = 0; 93 } 94 95 /* 96 * Version ::= INTEGER { v1(0) } 97 */ 98 static int x509_csr_get_version( unsigned char **p, 99 const unsigned char *end, 100 int *ver ) 101 { 102 int ret; 103 104 if( ( ret = mbedtls_asn1_get_int( p, end, ver ) ) != 0 ) 105 { 106 if( ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG ) 107 { 108 *ver = 0; 109 return( 0 ); 110 } 111 112 return( MBEDTLS_ERR_X509_INVALID_VERSION + ret ); 113 } 114 115 return( 0 ); 116 } 117 118 /* 119 * Parse a CSR in DER format 120 */ 121 int mbedtls_x509_csr_parse_der( mbedtls_x509_csr *csr, 122 const unsigned char *buf, size_t buflen ) 123 { 124 int ret; 125 size_t len; 126 unsigned char *p, *end; 127 mbedtls_x509_buf sig_params; 128 129 memset( &sig_params, 0, sizeof( mbedtls_x509_buf ) ); 130 131 /* 132 * Check for valid input 133 */ 134 if( csr == NULL || buf == NULL || buflen == 0 ) 135 return( MBEDTLS_ERR_X509_BAD_INPUT_DATA ); 136 137 mbedtls_x509_csr_init( csr ); 138 139 /* 140 * first copy the raw DER data 141 */ 142 p = mbedtls_calloc( 1, len = buflen ); 143 144 if( p == NULL ) 145 return( MBEDTLS_ERR_X509_ALLOC_FAILED ); 146 147 memcpy( p, buf, buflen ); 148 149 csr->raw.p = p; 150 csr->raw.len = len; 151 end = p + len; 152 153 /* 154 * CertificationRequest ::= SEQUENCE { 155 * certificationRequestInfo CertificationRequestInfo, 156 * signatureAlgorithm AlgorithmIdentifier, 157 * signature BIT STRING 158 * } 159 */ 160 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, 161 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) 162 { 163 mbedtls_x509_csr_free( csr ); 164 return( MBEDTLS_ERR_X509_INVALID_FORMAT ); 165 } 166 167 if( len != (size_t) ( end - p ) ) 168 { 169 mbedtls_x509_csr_free( csr ); 170 return( MBEDTLS_ERR_X509_INVALID_FORMAT + 171 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); 172 } 173 174 /* 175 * CertificationRequestInfo ::= SEQUENCE { 176 */ 177 csr->cri.p = p; 178 179 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, 180 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) 181 { 182 mbedtls_x509_csr_free( csr ); 183 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret ); 184 } 185 186 end = p + len; 187 csr->cri.len = end - csr->cri.p; 188 189 /* 190 * Version ::= INTEGER { v1(0) } 191 */ 192 if( ( ret = x509_csr_get_version( &p, end, &csr->version ) ) != 0 ) 193 { 194 mbedtls_x509_csr_free( csr ); 195 return( ret ); 196 } 197 198 if( csr->version != 0 ) 199 { 200 mbedtls_x509_csr_free( csr ); 201 return( MBEDTLS_ERR_X509_UNKNOWN_VERSION ); 202 } 203 204 csr->version++; 205 206 /* 207 * subject Name 208 */ 209 csr->subject_raw.p = p; 210 211 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, 212 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) 213 { 214 mbedtls_x509_csr_free( csr ); 215 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret ); 216 } 217 218 if( ( ret = mbedtls_x509_get_name( &p, p + len, &csr->subject ) ) != 0 ) 219 { 220 mbedtls_x509_csr_free( csr ); 221 return( ret ); 222 } 223 224 csr->subject_raw.len = p - csr->subject_raw.p; 225 226 /* 227 * subjectPKInfo SubjectPublicKeyInfo 228 */ 229 if( ( ret = mbedtls_pk_parse_subpubkey( &p, end, &csr->pk ) ) != 0 ) 230 { 231 mbedtls_x509_csr_free( csr ); 232 return( ret ); 233 } 234 235 /* 236 * attributes [0] Attributes 237 * 238 * The list of possible attributes is open-ended, though RFC 2985 239 * (PKCS#9) defines a few in section 5.4. We currently don't support any, 240 * so we just ignore them. This is a safe thing to do as the worst thing 241 * that could happen is that we issue a certificate that does not match 242 * the requester's expectations - this cannot cause a violation of our 243 * signature policies. 244 */ 245 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, 246 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC ) ) != 0 ) 247 { 248 mbedtls_x509_csr_free( csr ); 249 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret ); 250 } 251 252 p += len; 253 254 end = csr->raw.p + csr->raw.len; 255 256 /* 257 * signatureAlgorithm AlgorithmIdentifier, 258 * signature BIT STRING 259 */ 260 if( ( ret = mbedtls_x509_get_alg( &p, end, &csr->sig_oid, &sig_params ) ) != 0 ) 261 { 262 mbedtls_x509_csr_free( csr ); 263 return( ret ); 264 } 265 266 if( ( ret = mbedtls_x509_get_sig_alg( &csr->sig_oid, &sig_params, 267 &csr->sig_md, &csr->sig_pk, 268 &csr->sig_opts ) ) != 0 ) 269 { 270 mbedtls_x509_csr_free( csr ); 271 return( MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG ); 272 } 273 274 if( ( ret = mbedtls_x509_get_sig( &p, end, &csr->sig ) ) != 0 ) 275 { 276 mbedtls_x509_csr_free( csr ); 277 return( ret ); 278 } 279 280 if( p != end ) 281 { 282 mbedtls_x509_csr_free( csr ); 283 return( MBEDTLS_ERR_X509_INVALID_FORMAT + 284 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); 285 } 286 287 return( 0 ); 288 } 289 290 /* 291 * Parse a CSR, allowing for PEM or raw DER encoding 292 */ 293 int mbedtls_x509_csr_parse( mbedtls_x509_csr *csr, const unsigned char *buf, size_t buflen ) 294 { 295 #if defined(MBEDTLS_PEM_PARSE_C) 296 int ret; 297 size_t use_len; 298 mbedtls_pem_context pem; 299 #endif 300 301 /* 302 * Check for valid input 303 */ 304 if( csr == NULL || buf == NULL || buflen == 0 ) 305 return( MBEDTLS_ERR_X509_BAD_INPUT_DATA ); 306 307 #if defined(MBEDTLS_PEM_PARSE_C) 308 /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */ 309 if( buf[buflen - 1] == '\0' ) 310 { 311 mbedtls_pem_init( &pem ); 312 ret = mbedtls_pem_read_buffer( &pem, 313 "-----BEGIN CERTIFICATE REQUEST-----", 314 "-----END CERTIFICATE REQUEST-----", 315 buf, NULL, 0, &use_len ); 316 if( ret == MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) 317 { 318 ret = mbedtls_pem_read_buffer( &pem, 319 "-----BEGIN NEW CERTIFICATE REQUEST-----", 320 "-----END NEW CERTIFICATE REQUEST-----", 321 buf, NULL, 0, &use_len ); 322 } 323 324 if( ret == 0 ) 325 { 326 /* 327 * Was PEM encoded, parse the result 328 */ 329 ret = mbedtls_x509_csr_parse_der( csr, pem.buf, pem.buflen ); 330 } 331 332 mbedtls_pem_free( &pem ); 333 if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) 334 return( ret ); 335 } 336 #endif /* MBEDTLS_PEM_PARSE_C */ 337 return( mbedtls_x509_csr_parse_der( csr, buf, buflen ) ); 338 } 339 340 #if defined(MBEDTLS_FS_IO) 341 /* 342 * Load a CSR into the structure 343 */ 344 int mbedtls_x509_csr_parse_file( mbedtls_x509_csr *csr, const char *path ) 345 { 346 int ret; 347 size_t n; 348 unsigned char *buf; 349 350 if( ( ret = mbedtls_pk_load_file( path, &buf, &n ) ) != 0 ) 351 return( ret ); 352 353 ret = mbedtls_x509_csr_parse( csr, buf, n ); 354 355 mbedtls_zeroize( buf, n ); 356 mbedtls_free( buf ); 357 358 return( ret ); 359 } 360 #endif /* MBEDTLS_FS_IO */ 361 362 #define BEFORE_COLON 14 363 #define BC "14" 364 /* 365 * Return an informational string about the CSR. 366 */ 367 int mbedtls_x509_csr_info( char *buf, size_t size, const char *prefix, 368 const mbedtls_x509_csr *csr ) 369 { 370 int ret; 371 size_t n; 372 char *p; 373 char key_size_str[BEFORE_COLON]; 374 375 p = buf; 376 n = size; 377 378 ret = mbedtls_snprintf( p, n, "%sCSR version : %d", 379 prefix, csr->version ); 380 MBEDTLS_X509_SAFE_SNPRINTF; 381 382 ret = mbedtls_snprintf( p, n, "\n%ssubject name : ", prefix ); 383 MBEDTLS_X509_SAFE_SNPRINTF; 384 ret = mbedtls_x509_dn_gets( p, n, &csr->subject ); 385 MBEDTLS_X509_SAFE_SNPRINTF; 386 387 ret = mbedtls_snprintf( p, n, "\n%ssigned using : ", prefix ); 388 MBEDTLS_X509_SAFE_SNPRINTF; 389 390 ret = mbedtls_x509_sig_alg_gets( p, n, &csr->sig_oid, csr->sig_pk, csr->sig_md, 391 csr->sig_opts ); 392 MBEDTLS_X509_SAFE_SNPRINTF; 393 394 if( ( ret = mbedtls_x509_key_size_helper( key_size_str, BEFORE_COLON, 395 mbedtls_pk_get_name( &csr->pk ) ) ) != 0 ) 396 { 397 return( ret ); 398 } 399 400 ret = mbedtls_snprintf( p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str, 401 (int) mbedtls_pk_get_bitlen( &csr->pk ) ); 402 MBEDTLS_X509_SAFE_SNPRINTF; 403 404 return( (int) ( size - n ) ); 405 } 406 407 /* 408 * Initialize a CSR 409 */ 410 void mbedtls_x509_csr_init( mbedtls_x509_csr *csr ) 411 { 412 memset( csr, 0, sizeof(mbedtls_x509_csr) ); 413 } 414 415 /* 416 * Unallocate all CSR data 417 */ 418 void mbedtls_x509_csr_free( mbedtls_x509_csr *csr ) 419 { 420 mbedtls_x509_name *name_cur; 421 mbedtls_x509_name *name_prv; 422 423 if( csr == NULL ) 424 return; 425 426 mbedtls_pk_free( &csr->pk ); 427 428 #if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT) 429 mbedtls_free( csr->sig_opts ); 430 #endif 431 432 name_cur = csr->subject.next; 433 while( name_cur != NULL ) 434 { 435 name_prv = name_cur; 436 name_cur = name_cur->next; 437 mbedtls_zeroize( name_prv, sizeof( mbedtls_x509_name ) ); 438 mbedtls_free( name_prv ); 439 } 440 441 if( csr->raw.p != NULL ) 442 { 443 mbedtls_zeroize( csr->raw.p, csr->raw.len ); 444 mbedtls_free( csr->raw.p ); 445 } 446 447 mbedtls_zeroize( csr, sizeof( mbedtls_x509_csr ) ); 448 } 449 450 #endif /* MBEDTLS_X509_CSR_PARSE_C */ 451