1 /* 2 * ASN.1 buffer writing functionality 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 #if !defined(MBEDTLS_CONFIG_FILE) 50 #include "mbedtls/config.h" 51 #else 52 #include MBEDTLS_CONFIG_FILE 53 #endif 54 55 #if defined(MBEDTLS_ASN1_WRITE_C) 56 57 #include "mbedtls/asn1write.h" 58 59 #include <string.h> 60 61 #if defined(MBEDTLS_PLATFORM_C) 62 #include "mbedtls/platform.h" 63 #else 64 #include <stdlib.h> 65 #define mbedtls_calloc calloc 66 #define mbedtls_free free 67 #endif 68 69 int mbedtls_asn1_write_len( unsigned char **p, unsigned char *start, size_t len ) 70 { 71 if( len < 0x80 ) 72 { 73 if( *p - start < 1 ) 74 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 75 76 *--(*p) = (unsigned char) len; 77 return( 1 ); 78 } 79 80 if( len <= 0xFF ) 81 { 82 if( *p - start < 2 ) 83 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 84 85 *--(*p) = (unsigned char) len; 86 *--(*p) = 0x81; 87 return( 2 ); 88 } 89 90 if( len <= 0xFFFF ) 91 { 92 if( *p - start < 3 ) 93 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 94 95 *--(*p) = ( len ) & 0xFF; 96 *--(*p) = ( len >> 8 ) & 0xFF; 97 *--(*p) = 0x82; 98 return( 3 ); 99 } 100 101 if( len <= 0xFFFFFF ) 102 { 103 if( *p - start < 4 ) 104 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 105 106 *--(*p) = ( len ) & 0xFF; 107 *--(*p) = ( len >> 8 ) & 0xFF; 108 *--(*p) = ( len >> 16 ) & 0xFF; 109 *--(*p) = 0x83; 110 return( 4 ); 111 } 112 113 #if SIZE_MAX > 0xFFFFFFFF 114 if( len <= 0xFFFFFFFF ) 115 #endif 116 { 117 if( *p - start < 5 ) 118 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 119 120 *--(*p) = ( len ) & 0xFF; 121 *--(*p) = ( len >> 8 ) & 0xFF; 122 *--(*p) = ( len >> 16 ) & 0xFF; 123 *--(*p) = ( len >> 24 ) & 0xFF; 124 *--(*p) = 0x84; 125 return( 5 ); 126 } 127 128 #if SIZE_MAX > 0xFFFFFFFF 129 return( MBEDTLS_ERR_ASN1_INVALID_LENGTH ); 130 #endif 131 } 132 133 int mbedtls_asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag ) 134 { 135 if( *p - start < 1 ) 136 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 137 138 *--(*p) = tag; 139 140 return( 1 ); 141 } 142 143 int mbedtls_asn1_write_raw_buffer( unsigned char **p, unsigned char *start, 144 const unsigned char *buf, size_t size ) 145 { 146 size_t len = 0; 147 148 if( *p < start || (size_t)( *p - start ) < size ) 149 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 150 151 len = size; 152 (*p) -= len; 153 memcpy( *p, buf, len ); 154 155 return( (int) len ); 156 } 157 158 #if defined(MBEDTLS_BIGNUM_C) 159 int mbedtls_asn1_write_mpi( unsigned char **p, unsigned char *start, const mbedtls_mpi *X ) 160 { 161 int ret; 162 size_t len = 0; 163 164 // Write the MPI 165 // 166 len = mbedtls_mpi_size( X ); 167 168 if( *p < start || (size_t)( *p - start ) < len ) 169 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 170 171 (*p) -= len; 172 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( X, *p, len ) ); 173 174 // DER format assumes 2s complement for numbers, so the leftmost bit 175 // should be 0 for positive numbers and 1 for negative numbers. 176 // 177 if( X->s ==1 && **p & 0x80 ) 178 { 179 if( *p - start < 1 ) 180 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 181 182 *--(*p) = 0x00; 183 len += 1; 184 } 185 186 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 187 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) ); 188 189 ret = (int) len; 190 191 cleanup: 192 return( ret ); 193 } 194 #endif /* MBEDTLS_BIGNUM_C */ 195 196 int mbedtls_asn1_write_null( unsigned char **p, unsigned char *start ) 197 { 198 int ret; 199 size_t len = 0; 200 201 // Write NULL 202 // 203 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, 0) ); 204 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_NULL ) ); 205 206 return( (int) len ); 207 } 208 209 int mbedtls_asn1_write_oid( unsigned char **p, unsigned char *start, 210 const char *oid, size_t oid_len ) 211 { 212 int ret; 213 size_t len = 0; 214 215 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, 216 (const unsigned char *) oid, oid_len ) ); 217 MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_len( p, start, len ) ); 218 MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OID ) ); 219 220 return( (int) len ); 221 } 222 223 int mbedtls_asn1_write_algorithm_identifier( unsigned char **p, unsigned char *start, 224 const char *oid, size_t oid_len, 225 size_t par_len ) 226 { 227 int ret; 228 size_t len = 0; 229 230 if( par_len == 0 ) 231 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_null( p, start ) ); 232 else 233 len += par_len; 234 235 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid, oid_len ) ); 236 237 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 238 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, 239 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ); 240 241 return( (int) len ); 242 } 243 244 int mbedtls_asn1_write_bool( unsigned char **p, unsigned char *start, int boolean ) 245 { 246 int ret; 247 size_t len = 0; 248 249 if( *p - start < 1 ) 250 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 251 252 *--(*p) = (boolean) ? 255 : 0; 253 len++; 254 255 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 256 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BOOLEAN ) ); 257 258 return( (int) len ); 259 } 260 261 int mbedtls_asn1_write_int( unsigned char **p, unsigned char *start, int val ) 262 { 263 int ret; 264 size_t len = 0; 265 266 // DER format assumes 2s complement for numbers, so the leftmost bit 267 // should be 0 for positive numbers and 1 for negative numbers. 268 // 269 if( *p - start < 1 ) 270 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 271 272 len += 1; 273 *--(*p) = val; 274 275 if( val > 0 && **p & 0x80 ) 276 { 277 if( *p - start < 1 ) 278 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 279 280 *--(*p) = 0x00; 281 len += 1; 282 } 283 284 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 285 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) ); 286 287 return( (int) len ); 288 } 289 290 int mbedtls_asn1_write_printable_string( unsigned char **p, unsigned char *start, 291 const char *text, size_t text_len ) 292 { 293 int ret; 294 size_t len = 0; 295 296 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, 297 (const unsigned char *) text, text_len ) ); 298 299 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 300 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_PRINTABLE_STRING ) ); 301 302 return( (int) len ); 303 } 304 305 int mbedtls_asn1_write_ia5_string( unsigned char **p, unsigned char *start, 306 const char *text, size_t text_len ) 307 { 308 int ret; 309 size_t len = 0; 310 311 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, 312 (const unsigned char *) text, text_len ) ); 313 314 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 315 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_IA5_STRING ) ); 316 317 return( (int) len ); 318 } 319 320 int mbedtls_asn1_write_bitstring( unsigned char **p, unsigned char *start, 321 const unsigned char *buf, size_t bits ) 322 { 323 int ret; 324 size_t len = 0; 325 size_t unused_bits, byte_len; 326 327 byte_len = ( bits + 7 ) / 8; 328 unused_bits = ( byte_len * 8 ) - bits; 329 330 if( *p < start || (size_t)( *p - start ) < byte_len + 1 ) 331 return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL ); 332 333 len = byte_len + 1; 334 335 /* Write the bitstring. Ensure the unused bits are zeroed */ 336 if( byte_len > 0 ) 337 { 338 byte_len--; 339 *--( *p ) = buf[byte_len] & ~( ( 0x1 << unused_bits ) - 1 ); 340 ( *p ) -= byte_len; 341 memcpy( *p, buf, byte_len ); 342 } 343 344 /* Write unused bits */ 345 *--( *p ) = (unsigned char)unused_bits; 346 347 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 348 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BIT_STRING ) ); 349 350 return( (int) len ); 351 } 352 353 int mbedtls_asn1_write_octet_string( unsigned char **p, unsigned char *start, 354 const unsigned char *buf, size_t size ) 355 { 356 int ret; 357 size_t len = 0; 358 359 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, buf, size ) ); 360 361 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) ); 362 MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OCTET_STRING ) ); 363 364 return( (int) len ); 365 } 366 367 368 /* This is a copy of the ASN.1 parsing function mbedtls_asn1_find_named_data(), 369 * which is replicated to avoid a dependency ASN1_WRITE_C on ASN1_PARSE_C. */ 370 static mbedtls_asn1_named_data *asn1_find_named_data( 371 mbedtls_asn1_named_data *list, 372 const char *oid, size_t len ) 373 { 374 while( list != NULL ) 375 { 376 if( list->oid.len == len && 377 memcmp( list->oid.p, oid, len ) == 0 ) 378 { 379 break; 380 } 381 382 list = list->next; 383 } 384 385 return( list ); 386 } 387 388 mbedtls_asn1_named_data *mbedtls_asn1_store_named_data( 389 mbedtls_asn1_named_data **head, 390 const char *oid, size_t oid_len, 391 const unsigned char *val, 392 size_t val_len ) 393 { 394 mbedtls_asn1_named_data *cur; 395 396 if( ( cur = asn1_find_named_data( *head, oid, oid_len ) ) == NULL ) 397 { 398 // Add new entry if not present yet based on OID 399 // 400 cur = (mbedtls_asn1_named_data*)mbedtls_calloc( 1, 401 sizeof(mbedtls_asn1_named_data) ); 402 if( cur == NULL ) 403 return( NULL ); 404 405 cur->oid.len = oid_len; 406 cur->oid.p = mbedtls_calloc( 1, oid_len ); 407 if( cur->oid.p == NULL ) 408 { 409 mbedtls_free( cur ); 410 return( NULL ); 411 } 412 413 memcpy( cur->oid.p, oid, oid_len ); 414 415 cur->val.len = val_len; 416 cur->val.p = mbedtls_calloc( 1, val_len ); 417 if( cur->val.p == NULL ) 418 { 419 mbedtls_free( cur->oid.p ); 420 mbedtls_free( cur ); 421 return( NULL ); 422 } 423 424 cur->next = *head; 425 *head = cur; 426 } 427 else if( cur->val.len < val_len ) 428 { 429 /* 430 * Enlarge existing value buffer if needed 431 * Preserve old data until the allocation succeeded, to leave list in 432 * a consistent state in case allocation fails. 433 */ 434 void *p = mbedtls_calloc( 1, val_len ); 435 if( p == NULL ) 436 return( NULL ); 437 438 mbedtls_free( cur->val.p ); 439 cur->val.p = p; 440 cur->val.len = val_len; 441 } 442 443 if( val != NULL ) 444 memcpy( cur->val.p, val, val_len ); 445 446 return( cur ); 447 } 448 #endif /* MBEDTLS_ASN1_WRITE_C */ 449