| 1 | /* |
| 2 | * Generic ASN.1 parsing |
| 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 | #if !defined(MBEDTLS_CONFIG_FILE) |
| 25 | #include "mbedtls/config.h" |
| 26 | #else |
| 27 | #include MBEDTLS_CONFIG_FILE |
| 28 | #endif |
| 29 | |
| 30 | #if defined(MBEDTLS_ASN1_PARSE_C) |
| 31 | |
| 32 | #include "mbedtls/asn1.h" |
| 33 | #include "mbedtls/platform_util.h" |
| 34 | |
| 35 | #include <string.h> |
| 36 | |
| 37 | #if defined(MBEDTLS_BIGNUM_C) |
| 38 | #include "mbedtls/bignum.h" |
| 39 | #endif |
| 40 | |
| 41 | #if defined(MBEDTLS_PLATFORM_C) |
| 42 | #include "mbedtls/platform.h" |
| 43 | #else |
| 44 | #include <stdlib.h> |
| 45 | #define mbedtls_calloc calloc |
| 46 | #define mbedtls_free free |
| 47 | #endif |
| 48 | |
| 49 | /* |
| 50 | * ASN.1 DER decoding routines |
| 51 | */ |
| 52 | int mbedtls_asn1_get_len( unsigned char **p, |
| 53 | const unsigned char *end, |
| 54 | size_t *len ) |
| 55 | { |
| 56 | if( ( end - *p ) < 1 ) |
| 57 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); |
| 58 | |
| 59 | if( ( **p & 0x80 ) == 0 ) |
| 60 | *len = *(*p)++; |
| 61 | else |
| 62 | { |
| 63 | switch( **p & 0x7F ) |
| 64 | { |
| 65 | case 1: |
| 66 | if( ( end - *p ) < 2 ) |
| 67 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); |
| 68 | |
| 69 | *len = (*p)[1]; |
| 70 | (*p) += 2; |
| 71 | break; |
| 72 | |
| 73 | case 2: |
| 74 | if( ( end - *p ) < 3 ) |
| 75 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); |
| 76 | |
| 77 | *len = ( (size_t)(*p)[1] << 8 ) | (*p)[2]; |
| 78 | (*p) += 3; |
| 79 | break; |
| 80 | |
| 81 | case 3: |
| 82 | if( ( end - *p ) < 4 ) |
| 83 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); |
| 84 | |
| 85 | *len = ( (size_t)(*p)[1] << 16 ) | |
| 86 | ( (size_t)(*p)[2] << 8 ) | (*p)[3]; |
| 87 | (*p) += 4; |
| 88 | break; |
| 89 | |
| 90 | case 4: |
| 91 | if( ( end - *p ) < 5 ) |
| 92 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); |
| 93 | |
| 94 | *len = ( (size_t)(*p)[1] << 24 ) | ( (size_t)(*p)[2] << 16 ) | |
| 95 | ( (size_t)(*p)[3] << 8 ) | (*p)[4]; |
| 96 | (*p) += 5; |
| 97 | break; |
| 98 | |
| 99 | default: |
| 100 | return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | if( *len > (size_t) ( end - *p ) ) |
| 105 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); |
| 106 | |
| 107 | return( 0 ); |
| 108 | } |
| 109 | |
| 110 | int mbedtls_asn1_get_tag( unsigned char **p, |
| 111 | const unsigned char *end, |
| 112 | size_t *len, int tag ) |
| 113 | { |
| 114 | if( ( end - *p ) < 1 ) |
| 115 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); |
| 116 | |
| 117 | if( **p != tag ) |
| 118 | return( MBEDTLS_ERR_ASN1_UNEXPECTED_TAG ); |
| 119 | |
| 120 | (*p)++; |
| 121 | |
| 122 | return( mbedtls_asn1_get_len( p, end, len ) ); |
| 123 | } |
| 124 | |
| 125 | int mbedtls_asn1_get_bool( unsigned char **p, |
| 126 | const unsigned char *end, |
| 127 | int *val ) |
| 128 | { |
| 129 | int ret; |
| 130 | size_t len; |
| 131 | |
| 132 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_BOOLEAN ) ) != 0 ) |
| 133 | return( ret ); |
| 134 | |
| 135 | if( len != 1 ) |
| 136 | return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); |
| 137 | |
| 138 | *val = ( **p != 0 ) ? 1 : 0; |
| 139 | (*p)++; |
| 140 | |
| 141 | return( 0 ); |
| 142 | } |
| 143 | |
| 144 | int mbedtls_asn1_get_int( unsigned char **p, |
| 145 | const unsigned char *end, |
| 146 | int *val ) |
| 147 | { |
| 148 | int ret; |
| 149 | size_t len; |
| 150 | |
| 151 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 ) |
| 152 | return( ret ); |
| 153 | |
| 154 | if( len == 0 || len > sizeof( int ) || ( **p & 0x80 ) != 0 ) |
| 155 | return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); |
| 156 | |
| 157 | *val = 0; |
| 158 | |
| 159 | while( len-- > 0 ) |
| 160 | { |
| 161 | *val = ( *val << 8 ) | **p; |
| 162 | (*p)++; |
| 163 | } |
| 164 | |
| 165 | return( 0 ); |
| 166 | } |
| 167 | |
| 168 | #if defined(MBEDTLS_BIGNUM_C) |
| 169 | int mbedtls_asn1_get_mpi( unsigned char **p, |
| 170 | const unsigned char *end, |
| 171 | mbedtls_mpi *X ) |
| 172 | { |
| 173 | int ret; |
| 174 | size_t len; |
| 175 | |
| 176 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_INTEGER ) ) != 0 ) |
| 177 | return( ret ); |
| 178 | |
| 179 | ret = mbedtls_mpi_read_binary( X, *p, len ); |
| 180 | |
| 181 | *p += len; |
| 182 | |
| 183 | return( ret ); |
| 184 | } |
| 185 | #endif /* MBEDTLS_BIGNUM_C */ |
| 186 | |
| 187 | int mbedtls_asn1_get_bitstring( unsigned char **p, const unsigned char *end, |
| 188 | mbedtls_asn1_bitstring *bs) |
| 189 | { |
| 190 | int ret; |
| 191 | |
| 192 | /* Certificate type is a single byte bitstring */ |
| 193 | if( ( ret = mbedtls_asn1_get_tag( p, end, &bs->len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 ) |
| 194 | return( ret ); |
| 195 | |
| 196 | /* Check length, subtract one for actual bit string length */ |
| 197 | if( bs->len < 1 ) |
| 198 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); |
| 199 | bs->len -= 1; |
| 200 | |
| 201 | /* Get number of unused bits, ensure unused bits <= 7 */ |
| 202 | bs->unused_bits = **p; |
| 203 | if( bs->unused_bits > 7 ) |
| 204 | return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); |
| 205 | (*p)++; |
| 206 | |
| 207 | /* Get actual bitstring */ |
| 208 | bs->p = *p; |
| 209 | *p += bs->len; |
| 210 | |
| 211 | if( *p != end ) |
| 212 | return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); |
| 213 | |
| 214 | return( 0 ); |
| 215 | } |
| 216 | |
| 217 | /* |
| 218 | * Get a bit string without unused bits |
| 219 | */ |
| 220 | int mbedtls_asn1_get_bitstring_null( unsigned char **p, const unsigned char *end, |
| 221 | size_t *len ) |
| 222 | { |
| 223 | int ret; |
| 224 | |
| 225 | if( ( ret = mbedtls_asn1_get_tag( p, end, len, MBEDTLS_ASN1_BIT_STRING ) ) != 0 ) |
| 226 | return( ret ); |
| 227 | |
| 228 | if( (*len)-- < 2 || *(*p)++ != 0 ) |
| 229 | return( MBEDTLS_ERR_ASN1_INVALID_DATA ); |
| 230 | |
| 231 | return( 0 ); |
| 232 | } |
| 233 | |
| 234 | |
| 235 | |
| 236 | /* |
| 237 | * Parses and splits an ASN.1 "SEQUENCE OF <tag>" |
| 238 | */ |
| 239 | int mbedtls_asn1_get_sequence_of( unsigned char **p, |
| 240 | const unsigned char *end, |
| 241 | mbedtls_asn1_sequence *cur, |
| 242 | int tag) |
| 243 | { |
| 244 | int ret; |
| 245 | size_t len; |
| 246 | mbedtls_asn1_buf *buf; |
| 247 | |
| 248 | /* Get main sequence tag */ |
| 249 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len, |
| 250 | MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) |
| 251 | return( ret ); |
| 252 | |
| 253 | if( *p + len != end ) |
| 254 | return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); |
| 255 | |
| 256 | while( *p < end ) |
| 257 | { |
| 258 | buf = &(cur->buf); |
| 259 | buf->tag = **p; |
| 260 | |
| 261 | if( ( ret = mbedtls_asn1_get_tag( p, end, &buf->len, tag ) ) != 0 ) |
| 262 | return( ret ); |
| 263 | |
| 264 | buf->p = *p; |
| 265 | *p += buf->len; |
| 266 | |
| 267 | /* Allocate and assign next pointer */ |
| 268 | if( *p < end ) |
| 269 | { |
| 270 | cur->next = (mbedtls_asn1_sequence*)mbedtls_calloc( 1, |
| 271 | sizeof( mbedtls_asn1_sequence ) ); |
| 272 | |
| 273 | if( cur->next == NULL ) |
| 274 | return( MBEDTLS_ERR_ASN1_ALLOC_FAILED ); |
| 275 | |
| 276 | cur = cur->next; |
| 277 | } |
| 278 | } |
| 279 | |
| 280 | /* Set final sequence entry's next pointer to NULL */ |
| 281 | cur->next = NULL; |
| 282 | |
| 283 | if( *p != end ) |
| 284 | return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); |
| 285 | |
| 286 | return( 0 ); |
| 287 | } |
| 288 | |
| 289 | int mbedtls_asn1_get_alg( unsigned char **p, |
| 290 | const unsigned char *end, |
| 291 | mbedtls_asn1_buf *alg, mbedtls_asn1_buf *params ) |
| 292 | { |
| 293 | int ret; |
| 294 | size_t len; |
| 295 | |
| 296 | if( ( ret = mbedtls_asn1_get_tag( p, end, &len, |
| 297 | MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) |
| 298 | return( ret ); |
| 299 | |
| 300 | if( ( end - *p ) < 1 ) |
| 301 | return( MBEDTLS_ERR_ASN1_OUT_OF_DATA ); |
| 302 | |
| 303 | alg->tag = **p; |
| 304 | end = *p + len; |
| 305 | |
| 306 | if( ( ret = mbedtls_asn1_get_tag( p, end, &alg->len, MBEDTLS_ASN1_OID ) ) != 0 ) |
| 307 | return( ret ); |
| 308 | |
| 309 | alg->p = *p; |
| 310 | *p += alg->len; |
| 311 | |
| 312 | if( *p == end ) |
| 313 | { |
| 314 | mbedtls_platform_zeroize( params, sizeof(mbedtls_asn1_buf) ); |
| 315 | return( 0 ); |
| 316 | } |
| 317 | |
| 318 | params->tag = **p; |
| 319 | (*p)++; |
| 320 | |
| 321 | if( ( ret = mbedtls_asn1_get_len( p, end, ¶ms->len ) ) != 0 ) |
| 322 | return( ret ); |
| 323 | |
| 324 | params->p = *p; |
| 325 | *p += params->len; |
| 326 | |
| 327 | if( *p != end ) |
| 328 | return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); |
| 329 | |
| 330 | return( 0 ); |
| 331 | } |
| 332 | |
| 333 | int mbedtls_asn1_get_alg_null( unsigned char **p, |
| 334 | const unsigned char *end, |
| 335 | mbedtls_asn1_buf *alg ) |
| 336 | { |
| 337 | int ret; |
| 338 | mbedtls_asn1_buf params; |
| 339 | |
| 340 | memset( ¶ms, 0, sizeof(mbedtls_asn1_buf) ); |
| 341 | |
| 342 | if( ( ret = mbedtls_asn1_get_alg( p, end, alg, ¶ms ) ) != 0 ) |
| 343 | return( ret ); |
| 344 | |
| 345 | if( ( params.tag != MBEDTLS_ASN1_NULL && params.tag != 0 ) || params.len != 0 ) |
| 346 | return( MBEDTLS_ERR_ASN1_INVALID_DATA ); |
| 347 | |
| 348 | return( 0 ); |
| 349 | } |
| 350 | |
| 351 | void mbedtls_asn1_free_named_data( mbedtls_asn1_named_data *cur ) |
| 352 | { |
| 353 | if( cur == NULL ) |
| 354 | return; |
| 355 | |
| 356 | mbedtls_free( cur->oid.p ); |
| 357 | mbedtls_free( cur->val.p ); |
| 358 | |
| 359 | mbedtls_platform_zeroize( cur, sizeof( mbedtls_asn1_named_data ) ); |
| 360 | } |
| 361 | |
| 362 | void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head ) |
| 363 | { |
| 364 | mbedtls_asn1_named_data *cur; |
| 365 | |
| 366 | while( ( cur = *head ) != NULL ) |
| 367 | { |
| 368 | *head = cur->next; |
| 369 | mbedtls_asn1_free_named_data( cur ); |
| 370 | mbedtls_free( cur ); |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data *list, |
| 375 | const char *oid, size_t len ) |
| 376 | { |
| 377 | while( list != NULL ) |
| 378 | { |
| 379 | if( list->oid.len == len && |
| 380 | memcmp( list->oid.p, oid, len ) == 0 ) |
| 381 | { |
| 382 | break; |
| 383 | } |
| 384 | |
| 385 | list = list->next; |
| 386 | } |
| 387 | |
| 388 | return( list ); |
| 389 | } |
| 390 | |
| 391 | #endif /* MBEDTLS_ASN1_PARSE_C */ |