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/oid.h" 42 43 #include <string.h> 44 45 #if defined(MBEDTLS_PEM_PARSE_C) 46 #include "mbedtls/pem.h" 47 #endif 48 49 #if defined(MBEDTLS_PLATFORM_C) 50 #include "mbedtls/platform.h" 51 #else 52 #include <stdlib.h> 53 #include <stdio.h> 54 #define mbedtls_free free 55 #define mbedtls_calloc calloc 56 #define mbedtls_snprintf snprintf 57 #endif 58 59 #if defined(MBEDTLS_FS_IO) || defined(EFIX64) || defined(EFI32) 60 #include <stdio.h> 61 #endif 62 63 /* Implementation that should never be optimized out by the compiler */ 64 static void mbedtls_zeroize( void *v, size_t n ) { 65 volatile unsigned char *p = v; while( n-- ) *p++ = 0; 66 } 67 68 /* 69 * Version ::= INTEGER { v1(0) } 70 */ 71 static int x509_csr_get_version( unsigned char **p, 72 const unsigned char *end, 73 int *ver ) 74 { 75 int ret; 76 77 if( ( ret = mbedtls_asn1_get_int( p, end, ver ) ) != 0 ) 78 { 79 if( ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG ) 80 { 81 *ver = 0; 82 return( 0 ); 83 } 84 85 return( MBEDTLS_ERR_X509_INVALID_VERSION + ret ); 86 } 87 88 return( 0 ); 89 } 90 91 /* 92 * Parse a CSR in DER format 93 */ 94 int mbedtls_x509_csr_parse_der( mbedtls_x509_csr *csr, 95 const unsigned char *buf, size_t buflen ) 96 { 97 int ret; 98 size_t len; 99 unsigned char *p, *end; 100 mbedtls_x509_buf sig_params; 101 102 memset( &sig_params, 0, sizeof( mbedtls_x509_buf ) ); 103 104 /* 105 * Check for valid input 106 */ 107 if( csr == NULL || buf == NULL || buflen == 0 ) 108 return( MBEDTLS_ERR_X509_BAD_INPUT_DATA ); 109 110 mbedtls_x509_csr_init( csr ); 111 112 /* 113 * first copy the raw DER data 114 */ 115 p = mbedtls_calloc( 1, len = buflen ); 116 117 if( p == NULL ) 118 return( MBEDTLS_ERR_X509_ALLOC_FAILED ); 119 120 memcpy( p, buf, buflen ); 121 122 csr->raw.p = p; 123 csr->raw.len = len; 124 end = p + len; 125 126 /* 127 * CertificationRequest ::= SEQUENCE { 128 * certificationRequestInfo CertificationRequestInfo, 129 * signatureAlgorithm AlgorithmIdentifier, 130 * signature BIT STRING 131 * } 132 */ 133 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, 134 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) 135 { 136 mbedtls_x509_csr_free( csr ); 137 return( MBEDTLS_ERR_X509_INVALID_FORMAT ); 138 } 139 140 if( len != (size_t) ( end - p ) ) 141 { 142 mbedtls_x509_csr_free( csr ); 143 return( MBEDTLS_ERR_X509_INVALID_FORMAT + 144 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); 145 } 146 147 /* 148 * CertificationRequestInfo ::= SEQUENCE { 149 */ 150 csr->cri.p = p; 151 152 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, 153 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) 154 { 155 mbedtls_x509_csr_free( csr ); 156 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret ); 157 } 158 159 end = p + len; 160 csr->cri.len = end - csr->cri.p; 161 162 /* 163 * Version ::= INTEGER { v1(0) } 164 */ 165 if( ( ret = x509_csr_get_version( &p, end, &csr->version ) ) != 0 ) 166 { 167 mbedtls_x509_csr_free( csr ); 168 return( ret ); 169 } 170 171 if( csr->version != 0 ) 172 { 173 mbedtls_x509_csr_free( csr ); 174 return( MBEDTLS_ERR_X509_UNKNOWN_VERSION ); 175 } 176 177 csr->version++; 178 179 /* 180 * subject Name 181 */ 182 csr->subject_raw.p = p; 183 184 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, 185 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) 186 { 187 mbedtls_x509_csr_free( csr ); 188 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret ); 189 } 190 191 if( ( ret = mbedtls_x509_get_name( &p, p + len, &csr->subject ) ) != 0 ) 192 { 193 mbedtls_x509_csr_free( csr ); 194 return( ret ); 195 } 196 197 csr->subject_raw.len = p - csr->subject_raw.p; 198 199 /* 200 * subjectPKInfo SubjectPublicKeyInfo 201 */ 202 if( ( ret = mbedtls_pk_parse_subpubkey( &p, end, &csr->pk ) ) != 0 ) 203 { 204 mbedtls_x509_csr_free( csr ); 205 return( ret ); 206 } 207 208 /* 209 * attributes [0] Attributes 210 * 211 * The list of possible attributes is open-ended, though RFC 2985 212 * (PKCS#9) defines a few in section 5.4. We currently don't support any, 213 * so we just ignore them. This is a safe thing to do as the worst thing 214 * that could happen is that we issue a certificate that does not match 215 * the requester's expectations - this cannot cause a violation of our 216 * signature policies. 217 */ 218 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, 219 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC ) ) != 0 ) 220 { 221 mbedtls_x509_csr_free( csr ); 222 return( MBEDTLS_ERR_X509_INVALID_FORMAT + ret ); 223 } 224 225 p += len; 226 227 end = csr->raw.p + csr->raw.len; 228 229 /* 230 * signatureAlgorithm AlgorithmIdentifier, 231 * signature BIT STRING 232 */ 233 if( ( ret = mbedtls_x509_get_alg( &p, end, &csr->sig_oid, &sig_params ) ) != 0 ) 234 { 235 mbedtls_x509_csr_free( csr ); 236 return( ret ); 237 } 238 239 if( ( ret = mbedtls_x509_get_sig_alg( &csr->sig_oid, &sig_params, 240 &csr->sig_md, &csr->sig_pk, 241 &csr->sig_opts ) ) != 0 ) 242 { 243 mbedtls_x509_csr_free( csr ); 244 return( MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG ); 245 } 246 247 if( ( ret = mbedtls_x509_get_sig( &p, end, &csr->sig ) ) != 0 ) 248 { 249 mbedtls_x509_csr_free( csr ); 250 return( ret ); 251 } 252 253 if( p != end ) 254 { 255 mbedtls_x509_csr_free( csr ); 256 return( MBEDTLS_ERR_X509_INVALID_FORMAT + 257 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); 258 } 259 260 return( 0 ); 261 } 262 263 /* 264 * Parse a CSR, allowing for PEM or raw DER encoding 265 */ 266 int mbedtls_x509_csr_parse( mbedtls_x509_csr *csr, const unsigned char *buf, size_t buflen ) 267 { 268 #if defined(MBEDTLS_PEM_PARSE_C) 269 int ret; 270 size_t use_len; 271 mbedtls_pem_context pem; 272 #endif 273 274 /* 275 * Check for valid input 276 */ 277 if( csr == NULL || buf == NULL || buflen == 0 ) 278 return( MBEDTLS_ERR_X509_BAD_INPUT_DATA ); 279 280 #if defined(MBEDTLS_PEM_PARSE_C) 281 mbedtls_pem_init( &pem ); 282 283 /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */ 284 if( buf[buflen - 1] != '\0' ) 285 ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT; 286 else 287 ret = mbedtls_pem_read_buffer( &pem, 288 "-----BEGIN CERTIFICATE REQUEST-----", 289 "-----END CERTIFICATE REQUEST-----", 290 buf, NULL, 0, &use_len ); 291 292 if( ret == 0 ) 293 { 294 /* 295 * Was PEM encoded, parse the result 296 */ 297 if( ( ret = mbedtls_x509_csr_parse_der( csr, pem.buf, pem.buflen ) ) != 0 ) 298 return( ret ); 299 300 mbedtls_pem_free( &pem ); 301 return( 0 ); 302 } 303 else if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) 304 { 305 mbedtls_pem_free( &pem ); 306 return( ret ); 307 } 308 else 309 #endif /* MBEDTLS_PEM_PARSE_C */ 310 return( mbedtls_x509_csr_parse_der( csr, buf, buflen ) ); 311 } 312 313 #if defined(MBEDTLS_FS_IO) 314 /* 315 * Load a CSR into the structure 316 */ 317 int mbedtls_x509_csr_parse_file( mbedtls_x509_csr *csr, const char *path ) 318 { 319 int ret; 320 size_t n; 321 unsigned char *buf; 322 323 if( ( ret = mbedtls_pk_load_file( path, &buf, &n ) ) != 0 ) 324 return( ret ); 325 326 ret = mbedtls_x509_csr_parse( csr, buf, n ); 327 328 mbedtls_zeroize( buf, n ); 329 mbedtls_free( buf ); 330 331 return( ret ); 332 } 333 #endif /* MBEDTLS_FS_IO */ 334 335 #define BEFORE_COLON 14 336 #define BC "14" 337 /* 338 * Return an informational string about the CSR. 339 */ 340 int mbedtls_x509_csr_info( char *buf, size_t size, const char *prefix, 341 const mbedtls_x509_csr *csr ) 342 { 343 int ret; 344 size_t n; 345 char *p; 346 char key_size_str[BEFORE_COLON]; 347 348 p = buf; 349 n = size; 350 351 ret = mbedtls_snprintf( p, n, "%sCSR version : %d", 352 prefix, csr->version ); 353 MBEDTLS_X509_SAFE_SNPRINTF; 354 355 ret = mbedtls_snprintf( p, n, "\n%ssubject name : ", prefix ); 356 MBEDTLS_X509_SAFE_SNPRINTF; 357 ret = mbedtls_x509_dn_gets( p, n, &csr->subject ); 358 MBEDTLS_X509_SAFE_SNPRINTF; 359 360 ret = mbedtls_snprintf( p, n, "\n%ssigned using : ", prefix ); 361 MBEDTLS_X509_SAFE_SNPRINTF; 362 363 ret = mbedtls_x509_sig_alg_gets( p, n, &csr->sig_oid, csr->sig_pk, csr->sig_md, 364 csr->sig_opts ); 365 MBEDTLS_X509_SAFE_SNPRINTF; 366 367 if( ( ret = mbedtls_x509_key_size_helper( key_size_str, BEFORE_COLON, 368 mbedtls_pk_get_name( &csr->pk ) ) ) != 0 ) 369 { 370 return( ret ); 371 } 372 373 ret = mbedtls_snprintf( p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str, 374 (int) mbedtls_pk_get_bitlen( &csr->pk ) ); 375 MBEDTLS_X509_SAFE_SNPRINTF; 376 377 return( (int) ( size - n ) ); 378 } 379 380 /* 381 * Initialize a CSR 382 */ 383 void mbedtls_x509_csr_init( mbedtls_x509_csr *csr ) 384 { 385 memset( csr, 0, sizeof(mbedtls_x509_csr) ); 386 } 387 388 /* 389 * Unallocate all CSR data 390 */ 391 void mbedtls_x509_csr_free( mbedtls_x509_csr *csr ) 392 { 393 mbedtls_x509_name *name_cur; 394 mbedtls_x509_name *name_prv; 395 396 if( csr == NULL ) 397 return; 398 399 mbedtls_pk_free( &csr->pk ); 400 401 #if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT) 402 mbedtls_free( csr->sig_opts ); 403 #endif 404 405 name_cur = csr->subject.next; 406 while( name_cur != NULL ) 407 { 408 name_prv = name_cur; 409 name_cur = name_cur->next; 410 mbedtls_zeroize( name_prv, sizeof( mbedtls_x509_name ) ); 411 mbedtls_free( name_prv ); 412 } 413 414 if( csr->raw.p != NULL ) 415 { 416 mbedtls_zeroize( csr->raw.p, csr->raw.len ); 417 mbedtls_free( csr->raw.p ); 418 } 419 420 mbedtls_zeroize( csr, sizeof( mbedtls_x509_csr ) ); 421 } 422 423 #endif /* MBEDTLS_X509_CSR_PARSE_C */ 424