Paul Bakker | 7c6b2c3 | 2013-09-16 13:49:26 +0200 | [diff] [blame] | 1 | /* |
| 2 | * X.509 Certificate Signing Request (CSR) parsing |
| 3 | * |
| 4 | * Copyright (C) 2006-2013, Brainspark B.V. |
| 5 | * |
| 6 | * This file is part of PolarSSL (http://www.polarssl.org) |
| 7 | * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org> |
| 8 | * |
| 9 | * All rights reserved. |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or modify |
| 12 | * it under the terms of the GNU General Public License as published by |
| 13 | * the Free Software Foundation; either version 2 of the License, or |
| 14 | * (at your option) any later version. |
| 15 | * |
| 16 | * This program is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | * GNU General Public License for more details. |
| 20 | * |
| 21 | * You should have received a copy of the GNU General Public License along |
| 22 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 23 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 24 | */ |
| 25 | /* |
| 26 | * The ITU-T X.509 standard defines a certificate format for PKI. |
| 27 | * |
| 28 | * http://www.ietf.org/rfc/rfc3279.txt |
| 29 | * http://www.ietf.org/rfc/rfc3280.txt |
| 30 | * |
| 31 | * ftp://ftp.rsasecurity.com/pub/pkcs/ascii/pkcs-1v2.asc |
| 32 | * |
| 33 | * http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf |
| 34 | * http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf |
| 35 | */ |
| 36 | |
| 37 | #include "polarssl/config.h" |
| 38 | |
| 39 | #if defined(POLARSSL_X509_CSR_PARSE_C) |
| 40 | |
| 41 | #include "polarssl/x509_csr.h" |
| 42 | #include "polarssl/oid.h" |
| 43 | #if defined(POLARSSL_PEM_PARSE_C) |
| 44 | #include "polarssl/pem.h" |
| 45 | #endif |
| 46 | #if defined(POLARSSL_ASN1_WRITE_C) |
| 47 | #include "polarssl/asn1write.h" |
| 48 | #endif |
| 49 | |
| 50 | #if defined(POLARSSL_MEMORY_C) |
| 51 | #include "polarssl/memory.h" |
| 52 | #else |
| 53 | #define polarssl_malloc malloc |
| 54 | #define polarssl_free free |
| 55 | #endif |
| 56 | |
| 57 | #include <string.h> |
| 58 | #include <stdlib.h> |
| 59 | |
| 60 | #if defined(POLARSSL_FS_IO) |
| 61 | #include <stdio.h> |
| 62 | #endif |
| 63 | |
| 64 | /* |
| 65 | * Version ::= INTEGER { v1(0) } |
| 66 | */ |
| 67 | static int x509_csr_get_version( unsigned char **p, |
| 68 | const unsigned char *end, |
| 69 | int *ver ) |
| 70 | { |
| 71 | int ret; |
| 72 | |
| 73 | if( ( ret = asn1_get_int( p, end, ver ) ) != 0 ) |
| 74 | { |
| 75 | if( ret == POLARSSL_ERR_ASN1_UNEXPECTED_TAG ) |
| 76 | { |
| 77 | *ver = 0; |
| 78 | return( 0 ); |
| 79 | } |
| 80 | |
| 81 | return( POLARSSL_ERR_X509_CERT_INVALID_VERSION + ret ); |
| 82 | } |
| 83 | |
| 84 | return( 0 ); |
| 85 | } |
| 86 | |
| 87 | /* |
| 88 | * Parse a CSR |
| 89 | */ |
| 90 | int x509parse_csr( x509_csr *csr, const unsigned char *buf, size_t buflen ) |
| 91 | { |
| 92 | int ret; |
| 93 | size_t len; |
| 94 | unsigned char *p, *end; |
| 95 | #if defined(POLARSSL_PEM_PARSE_C) |
| 96 | size_t use_len; |
| 97 | pem_context pem; |
| 98 | #endif |
| 99 | |
| 100 | /* |
| 101 | * Check for valid input |
| 102 | */ |
| 103 | if( csr == NULL || buf == NULL ) |
| 104 | return( POLARSSL_ERR_X509_INVALID_INPUT ); |
| 105 | |
| 106 | memset( csr, 0, sizeof( x509_csr ) ); |
| 107 | |
| 108 | #if defined(POLARSSL_PEM_PARSE_C) |
| 109 | pem_init( &pem ); |
| 110 | ret = pem_read_buffer( &pem, |
| 111 | "-----BEGIN CERTIFICATE REQUEST-----", |
| 112 | "-----END CERTIFICATE REQUEST-----", |
| 113 | buf, NULL, 0, &use_len ); |
| 114 | |
| 115 | if( ret == 0 ) |
| 116 | { |
| 117 | /* |
| 118 | * Was PEM encoded |
| 119 | */ |
| 120 | buflen -= use_len; |
| 121 | buf += use_len; |
| 122 | |
| 123 | /* |
| 124 | * Steal PEM buffer |
| 125 | */ |
| 126 | p = pem.buf; |
| 127 | pem.buf = NULL; |
| 128 | len = pem.buflen; |
| 129 | pem_free( &pem ); |
| 130 | } |
| 131 | else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) |
| 132 | { |
| 133 | pem_free( &pem ); |
| 134 | return( ret ); |
| 135 | } |
| 136 | else |
| 137 | #endif |
| 138 | { |
| 139 | /* |
| 140 | * nope, copy the raw DER data |
| 141 | */ |
| 142 | p = (unsigned char *) polarssl_malloc( len = buflen ); |
| 143 | |
| 144 | if( p == NULL ) |
| 145 | return( POLARSSL_ERR_X509_MALLOC_FAILED ); |
| 146 | |
| 147 | memcpy( p, buf, buflen ); |
| 148 | |
| 149 | buflen = 0; |
| 150 | } |
| 151 | |
| 152 | csr->raw.p = p; |
| 153 | csr->raw.len = len; |
| 154 | end = p + len; |
| 155 | |
| 156 | /* |
| 157 | * CertificationRequest ::= SEQUENCE { |
| 158 | * certificationRequestInfo CertificationRequestInfo, |
| 159 | * signatureAlgorithm AlgorithmIdentifier, |
| 160 | * signature BIT STRING |
| 161 | * } |
| 162 | */ |
| 163 | if( ( ret = asn1_get_tag( &p, end, &len, |
| 164 | ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) |
| 165 | { |
| 166 | x509_csr_free( csr ); |
| 167 | return( POLARSSL_ERR_X509_CERT_INVALID_FORMAT ); |
| 168 | } |
| 169 | |
| 170 | if( len != (size_t) ( end - p ) ) |
| 171 | { |
| 172 | x509_csr_free( csr ); |
| 173 | return( POLARSSL_ERR_X509_CERT_INVALID_FORMAT + |
| 174 | POLARSSL_ERR_ASN1_LENGTH_MISMATCH ); |
| 175 | } |
| 176 | |
| 177 | /* |
| 178 | * CertificationRequestInfo ::= SEQUENCE { |
| 179 | */ |
| 180 | csr->cri.p = p; |
| 181 | |
| 182 | if( ( ret = asn1_get_tag( &p, end, &len, |
| 183 | ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) |
| 184 | { |
| 185 | x509_csr_free( csr ); |
| 186 | return( POLARSSL_ERR_X509_CERT_INVALID_FORMAT + ret ); |
| 187 | } |
| 188 | |
| 189 | end = p + len; |
| 190 | csr->cri.len = end - csr->cri.p; |
| 191 | |
| 192 | /* |
| 193 | * Version ::= INTEGER { v1(0) } |
| 194 | */ |
| 195 | if( ( ret = x509_csr_get_version( &p, end, &csr->version ) ) != 0 ) |
| 196 | { |
| 197 | x509_csr_free( csr ); |
| 198 | return( ret ); |
| 199 | } |
| 200 | |
| 201 | csr->version++; |
| 202 | |
| 203 | if( csr->version != 1 ) |
| 204 | { |
| 205 | x509_csr_free( csr ); |
| 206 | return( POLARSSL_ERR_X509_CERT_UNKNOWN_VERSION ); |
| 207 | } |
| 208 | |
| 209 | /* |
| 210 | * subject Name |
| 211 | */ |
| 212 | csr->subject_raw.p = p; |
| 213 | |
| 214 | if( ( ret = asn1_get_tag( &p, end, &len, |
| 215 | ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 ) |
| 216 | { |
| 217 | x509_csr_free( csr ); |
| 218 | return( POLARSSL_ERR_X509_CERT_INVALID_FORMAT + ret ); |
| 219 | } |
| 220 | |
| 221 | if( ( ret = x509_get_name( &p, p + len, &csr->subject ) ) != 0 ) |
| 222 | { |
| 223 | x509_csr_free( csr ); |
| 224 | return( ret ); |
| 225 | } |
| 226 | |
| 227 | csr->subject_raw.len = p - csr->subject_raw.p; |
| 228 | |
| 229 | /* |
| 230 | * subjectPKInfo SubjectPublicKeyInfo |
| 231 | */ |
| 232 | if( ( ret = pk_parse_get_pubkey( &p, end, &csr->pk ) ) != 0 ) |
| 233 | { |
| 234 | x509_csr_free( csr ); |
| 235 | return( ret ); |
| 236 | } |
| 237 | |
| 238 | /* |
| 239 | * attributes [0] Attributes |
| 240 | */ |
| 241 | if( ( ret = asn1_get_tag( &p, end, &len, |
| 242 | ASN1_CONSTRUCTED | ASN1_CONTEXT_SPECIFIC ) ) != 0 ) |
| 243 | { |
| 244 | x509_csr_free( csr ); |
| 245 | return( POLARSSL_ERR_X509_CERT_INVALID_FORMAT + ret ); |
| 246 | } |
| 247 | // TODO Parse Attributes / extension requests |
| 248 | |
| 249 | p += len; |
| 250 | |
| 251 | end = csr->raw.p + csr->raw.len; |
| 252 | |
| 253 | /* |
| 254 | * signatureAlgorithm AlgorithmIdentifier, |
| 255 | * signature BIT STRING |
| 256 | */ |
| 257 | if( ( ret = x509_get_alg_null( &p, end, &csr->sig_oid ) ) != 0 ) |
| 258 | { |
| 259 | x509_csr_free( csr ); |
| 260 | return( ret ); |
| 261 | } |
| 262 | |
| 263 | if( ( ret = x509_get_sig_alg( &csr->sig_oid, &csr->sig_md, |
| 264 | &csr->sig_pk ) ) != 0 ) |
| 265 | { |
| 266 | x509_csr_free( csr ); |
| 267 | return( POLARSSL_ERR_X509_CERT_UNKNOWN_SIG_ALG ); |
| 268 | } |
| 269 | |
| 270 | if( ( ret = x509_get_sig( &p, end, &csr->sig ) ) != 0 ) |
| 271 | { |
| 272 | x509_csr_free( csr ); |
| 273 | return( ret ); |
| 274 | } |
| 275 | |
| 276 | if( p != end ) |
| 277 | { |
| 278 | x509_csr_free( csr ); |
| 279 | return( POLARSSL_ERR_X509_CERT_INVALID_FORMAT + |
| 280 | POLARSSL_ERR_ASN1_LENGTH_MISMATCH ); |
| 281 | } |
| 282 | |
| 283 | return( 0 ); |
| 284 | } |
| 285 | |
| 286 | #if defined(POLARSSL_FS_IO) |
| 287 | /* |
| 288 | * Load a CSR into the structure |
| 289 | */ |
| 290 | int x509parse_csrfile( x509_csr *csr, const char *path ) |
| 291 | { |
| 292 | int ret; |
| 293 | size_t n; |
| 294 | unsigned char *buf; |
| 295 | |
| 296 | if ( ( ret = x509_load_file( path, &buf, &n ) ) != 0 ) |
| 297 | return( ret ); |
| 298 | |
| 299 | ret = x509parse_csr( csr, buf, n ); |
| 300 | |
| 301 | memset( buf, 0, n + 1 ); |
| 302 | polarssl_free( buf ); |
| 303 | |
| 304 | return( ret ); |
| 305 | } |
| 306 | #endif /* POLARSSL_FS_IO */ |
| 307 | |
| 308 | #if defined _MSC_VER && !defined snprintf |
| 309 | #include <stdarg.h> |
| 310 | |
| 311 | #if !defined vsnprintf |
| 312 | #define vsnprintf _vsnprintf |
| 313 | #endif // vsnprintf |
| 314 | |
| 315 | /* |
| 316 | * Windows _snprintf and _vsnprintf are not compatible to linux versions. |
| 317 | * Result value is not size of buffer needed, but -1 if no fit is possible. |
| 318 | * |
| 319 | * This fuction tries to 'fix' this by at least suggesting enlarging the |
| 320 | * size by 20. |
| 321 | */ |
| 322 | static int compat_snprintf(char *str, size_t size, const char *format, ...) |
| 323 | { |
| 324 | va_list ap; |
| 325 | int res = -1; |
| 326 | |
| 327 | va_start( ap, format ); |
| 328 | |
| 329 | res = vsnprintf( str, size, format, ap ); |
| 330 | |
| 331 | va_end( ap ); |
| 332 | |
| 333 | // No quick fix possible |
| 334 | if ( res < 0 ) |
| 335 | return( (int) size + 20 ); |
| 336 | |
| 337 | return res; |
| 338 | } |
| 339 | |
| 340 | #define snprintf compat_snprintf |
| 341 | #endif |
| 342 | |
| 343 | #define POLARSSL_ERR_DEBUG_BUF_TOO_SMALL -2 |
| 344 | |
| 345 | #define SAFE_SNPRINTF() \ |
| 346 | { \ |
| 347 | if( ret == -1 ) \ |
| 348 | return( -1 ); \ |
| 349 | \ |
| 350 | if ( (unsigned int) ret > n ) { \ |
| 351 | p[n - 1] = '\0'; \ |
| 352 | return POLARSSL_ERR_DEBUG_BUF_TOO_SMALL;\ |
| 353 | } \ |
| 354 | \ |
| 355 | n -= (unsigned int) ret; \ |
| 356 | p += (unsigned int) ret; \ |
| 357 | } |
| 358 | |
| 359 | #define BEFORE_COLON 14 |
| 360 | #define BC "14" |
| 361 | /* |
| 362 | * Return an informational string about the CSR. |
| 363 | */ |
| 364 | int x509parse_csr_info( char *buf, size_t size, const char *prefix, |
| 365 | const x509_csr *csr ) |
| 366 | { |
| 367 | int ret; |
| 368 | size_t n; |
| 369 | char *p; |
| 370 | const char *desc; |
| 371 | char key_size_str[BEFORE_COLON]; |
| 372 | |
| 373 | p = buf; |
| 374 | n = size; |
| 375 | |
| 376 | ret = snprintf( p, n, "%sCSR version : %d", |
| 377 | prefix, csr->version ); |
| 378 | SAFE_SNPRINTF(); |
| 379 | |
| 380 | ret = snprintf( p, n, "\n%ssubject name : ", prefix ); |
| 381 | SAFE_SNPRINTF(); |
| 382 | ret = x509parse_dn_gets( p, n, &csr->subject ); |
| 383 | SAFE_SNPRINTF(); |
| 384 | |
| 385 | ret = snprintf( p, n, "\n%ssigned using : ", prefix ); |
| 386 | SAFE_SNPRINTF(); |
| 387 | |
| 388 | ret = oid_get_sig_alg_desc( &csr->sig_oid, &desc ); |
| 389 | if( ret != 0 ) |
| 390 | ret = snprintf( p, n, "???" ); |
| 391 | else |
| 392 | ret = snprintf( p, n, "%s", desc ); |
| 393 | SAFE_SNPRINTF(); |
| 394 | |
| 395 | if( ( ret = x509_key_size_helper( key_size_str, BEFORE_COLON, |
| 396 | pk_get_name( &csr->pk ) ) ) != 0 ) |
| 397 | { |
| 398 | return( ret ); |
| 399 | } |
| 400 | |
| 401 | ret = snprintf( p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str, |
| 402 | (int) pk_get_size( &csr->pk ) ); |
| 403 | SAFE_SNPRINTF(); |
| 404 | |
| 405 | return( (int) ( size - n ) ); |
| 406 | } |
| 407 | |
| 408 | /* |
| 409 | * Unallocate all CSR data |
| 410 | */ |
| 411 | void x509_csr_free( x509_csr *csr ) |
| 412 | { |
| 413 | x509_name *name_cur; |
| 414 | x509_name *name_prv; |
| 415 | |
| 416 | if( csr == NULL ) |
| 417 | return; |
| 418 | |
| 419 | pk_free( &csr->pk ); |
| 420 | |
| 421 | name_cur = csr->subject.next; |
| 422 | while( name_cur != NULL ) |
| 423 | { |
| 424 | name_prv = name_cur; |
| 425 | name_cur = name_cur->next; |
| 426 | memset( name_prv, 0, sizeof( x509_name ) ); |
| 427 | polarssl_free( name_prv ); |
| 428 | } |
| 429 | |
| 430 | if( csr->raw.p != NULL ) |
| 431 | { |
| 432 | memset( csr->raw.p, 0, csr->raw.len ); |
| 433 | polarssl_free( csr->raw.p ); |
| 434 | } |
| 435 | |
| 436 | memset( csr, 0, sizeof( x509_csr ) ); |
| 437 | } |
| 438 | |
| 439 | #endif /* POLARSSL_X509_CSR_PARSE_C */ |