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