1 // SPDX-License-Identifier: Apache-2.0 2 /** 3 * \file cipher.c 4 * 5 * \brief Generic cipher wrapper for mbed TLS 6 * 7 * \author Adriaan de Jong <dejong@fox-it.com> 8 * 9 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 10 * 11 * Licensed under the Apache License, Version 2.0 (the "License"); you may 12 * not use this file except in compliance with the License. 13 * You may obtain a copy of the License at 14 * 15 * http://www.apache.org/licenses/LICENSE-2.0 16 * 17 * Unless required by applicable law or agreed to in writing, software 18 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 19 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 20 * See the License for the specific language governing permissions and 21 * limitations under the License. 22 * 23 * This file is part of mbed TLS (https://tls.mbed.org) 24 */ 25 26 #if !defined(MBEDTLS_CONFIG_FILE) 27 #include "mbedtls/config.h" 28 #else 29 #include MBEDTLS_CONFIG_FILE 30 #endif 31 32 #if defined(MBEDTLS_CIPHER_C) 33 34 #include "mbedtls/cipher.h" 35 #include "mbedtls/cipher_internal.h" 36 #include "mbedtls/platform_util.h" 37 38 #include <stdlib.h> 39 #include <string.h> 40 41 #if defined(MBEDTLS_CHACHAPOLY_C) 42 #include "mbedtls/chachapoly.h" 43 #endif 44 45 #if defined(MBEDTLS_GCM_C) 46 #include "mbedtls/gcm.h" 47 #endif 48 49 #if defined(MBEDTLS_CCM_C) 50 #include "mbedtls/ccm.h" 51 #endif 52 53 #if defined(MBEDTLS_CHACHA20_C) 54 #include "mbedtls/chacha20.h" 55 #endif 56 57 #if defined(MBEDTLS_CMAC_C) 58 #include "mbedtls/cmac.h" 59 #endif 60 61 #if defined(MBEDTLS_PLATFORM_C) 62 #include "mbedtls/platform.h" 63 #else 64 #define mbedtls_calloc calloc 65 #define mbedtls_free free 66 #endif 67 68 #define CIPHER_VALIDATE_RET( cond ) \ 69 MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ) 70 #define CIPHER_VALIDATE( cond ) \ 71 MBEDTLS_INTERNAL_VALIDATE( cond ) 72 73 #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C) 74 /* Compare the contents of two buffers in constant time. 75 * Returns 0 if the contents are bitwise identical, otherwise returns 76 * a non-zero value. 77 * This is currently only used by GCM and ChaCha20+Poly1305. 78 */ 79 static int mbedtls_constant_time_memcmp( const void *v1, const void *v2, size_t len ) 80 { 81 const unsigned char *p1 = (const unsigned char*) v1; 82 const unsigned char *p2 = (const unsigned char*) v2; 83 size_t i; 84 unsigned char diff; 85 86 for( diff = 0, i = 0; i < len; i++ ) 87 diff |= p1[i] ^ p2[i]; 88 89 return( (int)diff ); 90 } 91 #endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */ 92 93 static int supported_init = 0; 94 95 const int *mbedtls_cipher_list( void ) 96 { 97 const mbedtls_cipher_definition_t *def; 98 int *type; 99 100 if( ! supported_init ) 101 { 102 def = mbedtls_cipher_definitions; 103 type = mbedtls_cipher_supported; 104 105 while( def->type != 0 ) 106 *type++ = (*def++).type; 107 108 *type = 0; 109 110 supported_init = 1; 111 } 112 113 return( mbedtls_cipher_supported ); 114 } 115 116 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_type( const mbedtls_cipher_type_t cipher_type ) 117 { 118 const mbedtls_cipher_definition_t *def; 119 120 for( def = mbedtls_cipher_definitions; def->info != NULL; def++ ) 121 if( def->type == cipher_type ) 122 return( def->info ); 123 124 return( NULL ); 125 } 126 127 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_string( const char *cipher_name ) 128 { 129 const mbedtls_cipher_definition_t *def; 130 131 if( NULL == cipher_name ) 132 return( NULL ); 133 134 for( def = mbedtls_cipher_definitions; def->info != NULL; def++ ) 135 if( ! strcmp( def->info->name, cipher_name ) ) 136 return( def->info ); 137 138 return( NULL ); 139 } 140 141 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_values( const mbedtls_cipher_id_t cipher_id, 142 int key_bitlen, 143 const mbedtls_cipher_mode_t mode ) 144 { 145 const mbedtls_cipher_definition_t *def; 146 147 for( def = mbedtls_cipher_definitions; def->info != NULL; def++ ) 148 if( def->info->base->cipher == cipher_id && 149 def->info->key_bitlen == (unsigned) key_bitlen && 150 def->info->mode == mode ) 151 return( def->info ); 152 153 return( NULL ); 154 } 155 156 void mbedtls_cipher_init( mbedtls_cipher_context_t *ctx ) 157 { 158 CIPHER_VALIDATE( ctx != NULL ); 159 memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) ); 160 } 161 162 void mbedtls_cipher_free( mbedtls_cipher_context_t *ctx ) 163 { 164 if( ctx == NULL ) 165 return; 166 167 #if defined(MBEDTLS_CMAC_C) 168 if( ctx->cmac_ctx ) 169 { 170 mbedtls_platform_zeroize( ctx->cmac_ctx, 171 sizeof( mbedtls_cmac_context_t ) ); 172 mbedtls_free( ctx->cmac_ctx ); 173 } 174 #endif 175 176 if( ctx->cipher_ctx ) 177 ctx->cipher_info->base->ctx_free_func( ctx->cipher_ctx ); 178 179 mbedtls_platform_zeroize( ctx, sizeof(mbedtls_cipher_context_t) ); 180 } 181 182 int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx, const mbedtls_cipher_info_t *cipher_info ) 183 { 184 CIPHER_VALIDATE_RET( ctx != NULL ); 185 if( cipher_info == NULL ) 186 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 187 188 memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) ); 189 190 if( NULL == ( ctx->cipher_ctx = cipher_info->base->ctx_alloc_func() ) ) 191 return( MBEDTLS_ERR_CIPHER_ALLOC_FAILED ); 192 193 ctx->cipher_info = cipher_info; 194 195 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) 196 /* 197 * Ignore possible errors caused by a cipher mode that doesn't use padding 198 */ 199 #if defined(MBEDTLS_CIPHER_PADDING_PKCS7) 200 (void) mbedtls_cipher_set_padding_mode( ctx, MBEDTLS_PADDING_PKCS7 ); 201 #else 202 (void) mbedtls_cipher_set_padding_mode( ctx, MBEDTLS_PADDING_NONE ); 203 #endif 204 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */ 205 206 return( 0 ); 207 } 208 209 int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx, 210 const unsigned char *key, 211 int key_bitlen, 212 const mbedtls_operation_t operation ) 213 { 214 CIPHER_VALIDATE_RET( ctx != NULL ); 215 CIPHER_VALIDATE_RET( key != NULL ); 216 CIPHER_VALIDATE_RET( operation == MBEDTLS_ENCRYPT || 217 operation == MBEDTLS_DECRYPT ); 218 if( ctx->cipher_info == NULL ) 219 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 220 221 if( ( ctx->cipher_info->flags & MBEDTLS_CIPHER_VARIABLE_KEY_LEN ) == 0 && 222 (int) ctx->cipher_info->key_bitlen != key_bitlen ) 223 { 224 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 225 } 226 227 ctx->key_bitlen = key_bitlen; 228 ctx->operation = operation; 229 230 /* 231 * For OFB, CFB and CTR mode always use the encryption key schedule 232 */ 233 if( MBEDTLS_ENCRYPT == operation || 234 MBEDTLS_MODE_CFB == ctx->cipher_info->mode || 235 MBEDTLS_MODE_OFB == ctx->cipher_info->mode || 236 MBEDTLS_MODE_CTR == ctx->cipher_info->mode ) 237 { 238 return( ctx->cipher_info->base->setkey_enc_func( ctx->cipher_ctx, key, 239 ctx->key_bitlen ) ); 240 } 241 242 if( MBEDTLS_DECRYPT == operation ) 243 return( ctx->cipher_info->base->setkey_dec_func( ctx->cipher_ctx, key, 244 ctx->key_bitlen ) ); 245 246 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 247 } 248 249 int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx, 250 const unsigned char *iv, 251 size_t iv_len ) 252 { 253 size_t actual_iv_size; 254 255 CIPHER_VALIDATE_RET( ctx != NULL ); 256 CIPHER_VALIDATE_RET( iv_len == 0 || iv != NULL ); 257 if( ctx->cipher_info == NULL ) 258 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 259 260 /* avoid buffer overflow in ctx->iv */ 261 if( iv_len > MBEDTLS_MAX_IV_LENGTH ) 262 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 263 264 if( ( ctx->cipher_info->flags & MBEDTLS_CIPHER_VARIABLE_IV_LEN ) != 0 ) 265 actual_iv_size = iv_len; 266 else 267 { 268 actual_iv_size = ctx->cipher_info->iv_size; 269 270 /* avoid reading past the end of input buffer */ 271 if( actual_iv_size > iv_len ) 272 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 273 } 274 275 #if defined(MBEDTLS_CHACHA20_C) 276 if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20 ) 277 { 278 if ( 0 != mbedtls_chacha20_starts( (mbedtls_chacha20_context*)ctx->cipher_ctx, 279 iv, 280 0U ) ) /* Initial counter value */ 281 { 282 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 283 } 284 } 285 #endif 286 287 if ( actual_iv_size != 0 ) 288 { 289 memcpy( ctx->iv, iv, actual_iv_size ); 290 ctx->iv_size = actual_iv_size; 291 } 292 293 return( 0 ); 294 } 295 296 int mbedtls_cipher_reset( mbedtls_cipher_context_t *ctx ) 297 { 298 CIPHER_VALIDATE_RET( ctx != NULL ); 299 if( ctx->cipher_info == NULL ) 300 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 301 302 ctx->unprocessed_len = 0; 303 304 return( 0 ); 305 } 306 307 #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C) 308 int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx, 309 const unsigned char *ad, size_t ad_len ) 310 { 311 CIPHER_VALIDATE_RET( ctx != NULL ); 312 CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL ); 313 if( ctx->cipher_info == NULL ) 314 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 315 316 #if defined(MBEDTLS_GCM_C) 317 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 318 { 319 return( mbedtls_gcm_starts( (mbedtls_gcm_context *) ctx->cipher_ctx, ctx->operation, 320 ctx->iv, ctx->iv_size, ad, ad_len ) ); 321 } 322 #endif 323 324 #if defined(MBEDTLS_CHACHAPOLY_C) 325 if (MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 326 { 327 int result; 328 mbedtls_chachapoly_mode_t mode; 329 330 mode = ( ctx->operation == MBEDTLS_ENCRYPT ) 331 ? MBEDTLS_CHACHAPOLY_ENCRYPT 332 : MBEDTLS_CHACHAPOLY_DECRYPT; 333 334 result = mbedtls_chachapoly_starts( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 335 ctx->iv, 336 mode ); 337 if ( result != 0 ) 338 return( result ); 339 340 return( mbedtls_chachapoly_update_aad( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 341 ad, ad_len ) ); 342 } 343 #endif 344 345 return( 0 ); 346 } 347 #endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */ 348 349 int mbedtls_cipher_update( mbedtls_cipher_context_t *ctx, const unsigned char *input, 350 size_t ilen, unsigned char *output, size_t *olen ) 351 { 352 int ret; 353 size_t block_size; 354 355 CIPHER_VALIDATE_RET( ctx != NULL ); 356 CIPHER_VALIDATE_RET( ilen == 0 || input != NULL ); 357 CIPHER_VALIDATE_RET( output != NULL ); 358 CIPHER_VALIDATE_RET( olen != NULL ); 359 if( ctx->cipher_info == NULL ) 360 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 361 362 *olen = 0; 363 block_size = mbedtls_cipher_get_block_size( ctx ); 364 365 if( ctx->cipher_info->mode == MBEDTLS_MODE_ECB ) 366 { 367 if( ilen != block_size ) 368 return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); 369 370 *olen = ilen; 371 372 if( 0 != ( ret = ctx->cipher_info->base->ecb_func( ctx->cipher_ctx, 373 ctx->operation, input, output ) ) ) 374 { 375 return( ret ); 376 } 377 378 return( 0 ); 379 } 380 381 #if defined(MBEDTLS_GCM_C) 382 if( ctx->cipher_info->mode == MBEDTLS_MODE_GCM ) 383 { 384 *olen = ilen; 385 return( mbedtls_gcm_update( (mbedtls_gcm_context *) ctx->cipher_ctx, ilen, input, 386 output ) ); 387 } 388 #endif 389 390 #if defined(MBEDTLS_CHACHAPOLY_C) 391 if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20_POLY1305 ) 392 { 393 *olen = ilen; 394 return( mbedtls_chachapoly_update( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 395 ilen, input, output ) ); 396 } 397 #endif 398 399 if ( 0 == block_size ) 400 { 401 return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT ); 402 } 403 404 if( input == output && 405 ( ctx->unprocessed_len != 0 || ilen % block_size ) ) 406 { 407 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 408 } 409 410 #if defined(MBEDTLS_CIPHER_MODE_CBC) 411 if( ctx->cipher_info->mode == MBEDTLS_MODE_CBC ) 412 { 413 size_t copy_len = 0; 414 415 /* 416 * If there is not enough data for a full block, cache it. 417 */ 418 if( ( ctx->operation == MBEDTLS_DECRYPT && NULL != ctx->add_padding && 419 ilen <= block_size - ctx->unprocessed_len ) || 420 ( ctx->operation == MBEDTLS_DECRYPT && NULL == ctx->add_padding && 421 ilen < block_size - ctx->unprocessed_len ) || 422 ( ctx->operation == MBEDTLS_ENCRYPT && 423 ilen < block_size - ctx->unprocessed_len ) ) 424 { 425 memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input, 426 ilen ); 427 428 ctx->unprocessed_len += ilen; 429 return( 0 ); 430 } 431 432 /* 433 * Process cached data first 434 */ 435 if( 0 != ctx->unprocessed_len ) 436 { 437 copy_len = block_size - ctx->unprocessed_len; 438 439 memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input, 440 copy_len ); 441 442 if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx, 443 ctx->operation, block_size, ctx->iv, 444 ctx->unprocessed_data, output ) ) ) 445 { 446 return( ret ); 447 } 448 449 *olen += block_size; 450 output += block_size; 451 ctx->unprocessed_len = 0; 452 453 input += copy_len; 454 ilen -= copy_len; 455 } 456 457 /* 458 * Cache final, incomplete block 459 */ 460 if( 0 != ilen ) 461 { 462 if( 0 == block_size ) 463 { 464 return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT ); 465 } 466 467 /* Encryption: only cache partial blocks 468 * Decryption w/ padding: always keep at least one whole block 469 * Decryption w/o padding: only cache partial blocks 470 */ 471 copy_len = ilen % block_size; 472 if( copy_len == 0 && 473 ctx->operation == MBEDTLS_DECRYPT && 474 NULL != ctx->add_padding) 475 { 476 copy_len = block_size; 477 } 478 479 memcpy( ctx->unprocessed_data, &( input[ilen - copy_len] ), 480 copy_len ); 481 482 ctx->unprocessed_len += copy_len; 483 ilen -= copy_len; 484 } 485 486 /* 487 * Process remaining full blocks 488 */ 489 if( ilen ) 490 { 491 if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx, 492 ctx->operation, ilen, ctx->iv, input, output ) ) ) 493 { 494 return( ret ); 495 } 496 497 *olen += ilen; 498 } 499 500 return( 0 ); 501 } 502 #endif /* MBEDTLS_CIPHER_MODE_CBC */ 503 504 #if defined(MBEDTLS_CIPHER_MODE_CFB) 505 if( ctx->cipher_info->mode == MBEDTLS_MODE_CFB ) 506 { 507 if( 0 != ( ret = ctx->cipher_info->base->cfb_func( ctx->cipher_ctx, 508 ctx->operation, ilen, &ctx->unprocessed_len, ctx->iv, 509 input, output ) ) ) 510 { 511 return( ret ); 512 } 513 514 *olen = ilen; 515 516 return( 0 ); 517 } 518 #endif /* MBEDTLS_CIPHER_MODE_CFB */ 519 520 #if defined(MBEDTLS_CIPHER_MODE_OFB) 521 if( ctx->cipher_info->mode == MBEDTLS_MODE_OFB ) 522 { 523 if( 0 != ( ret = ctx->cipher_info->base->ofb_func( ctx->cipher_ctx, 524 ilen, &ctx->unprocessed_len, ctx->iv, input, output ) ) ) 525 { 526 return( ret ); 527 } 528 529 *olen = ilen; 530 531 return( 0 ); 532 } 533 #endif /* MBEDTLS_CIPHER_MODE_OFB */ 534 535 #if defined(MBEDTLS_CIPHER_MODE_CTR) 536 if( ctx->cipher_info->mode == MBEDTLS_MODE_CTR ) 537 { 538 if( 0 != ( ret = ctx->cipher_info->base->ctr_func( ctx->cipher_ctx, 539 ilen, &ctx->unprocessed_len, ctx->iv, 540 ctx->unprocessed_data, input, output ) ) ) 541 { 542 return( ret ); 543 } 544 545 *olen = ilen; 546 547 return( 0 ); 548 } 549 #endif /* MBEDTLS_CIPHER_MODE_CTR */ 550 551 #if defined(MBEDTLS_CIPHER_MODE_XTS) 552 if( ctx->cipher_info->mode == MBEDTLS_MODE_XTS ) 553 { 554 if( ctx->unprocessed_len > 0 ) { 555 /* We can only process an entire data unit at a time. */ 556 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 557 } 558 559 ret = ctx->cipher_info->base->xts_func( ctx->cipher_ctx, 560 ctx->operation, ilen, ctx->iv, input, output ); 561 if( ret != 0 ) 562 { 563 return( ret ); 564 } 565 566 *olen = ilen; 567 568 return( 0 ); 569 } 570 #endif /* MBEDTLS_CIPHER_MODE_XTS */ 571 572 #if defined(MBEDTLS_CIPHER_MODE_STREAM) 573 if( ctx->cipher_info->mode == MBEDTLS_MODE_STREAM ) 574 { 575 if( 0 != ( ret = ctx->cipher_info->base->stream_func( ctx->cipher_ctx, 576 ilen, input, output ) ) ) 577 { 578 return( ret ); 579 } 580 581 *olen = ilen; 582 583 return( 0 ); 584 } 585 #endif /* MBEDTLS_CIPHER_MODE_STREAM */ 586 587 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 588 } 589 590 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) 591 #if defined(MBEDTLS_CIPHER_PADDING_PKCS7) 592 /* 593 * PKCS7 (and PKCS5) padding: fill with ll bytes, with ll = padding_len 594 */ 595 static void add_pkcs_padding( unsigned char *output, size_t output_len, 596 size_t data_len ) 597 { 598 size_t padding_len = output_len - data_len; 599 unsigned char i; 600 601 for( i = 0; i < padding_len; i++ ) 602 output[data_len + i] = (unsigned char) padding_len; 603 } 604 605 static int get_pkcs_padding( unsigned char *input, size_t input_len, 606 size_t *data_len ) 607 { 608 size_t i, pad_idx; 609 unsigned char padding_len, bad = 0; 610 611 if( NULL == input || NULL == data_len ) 612 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 613 614 padding_len = input[input_len - 1]; 615 *data_len = input_len - padding_len; 616 617 /* Avoid logical || since it results in a branch */ 618 bad |= padding_len > input_len; 619 bad |= padding_len == 0; 620 621 /* The number of bytes checked must be independent of padding_len, 622 * so pick input_len, which is usually 8 or 16 (one block) */ 623 pad_idx = input_len - padding_len; 624 for( i = 0; i < input_len; i++ ) 625 bad |= ( input[i] ^ padding_len ) * ( i >= pad_idx ); 626 627 return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) ); 628 } 629 #endif /* MBEDTLS_CIPHER_PADDING_PKCS7 */ 630 631 #if defined(MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS) 632 /* 633 * One and zeros padding: fill with 80 00 ... 00 634 */ 635 static void add_one_and_zeros_padding( unsigned char *output, 636 size_t output_len, size_t data_len ) 637 { 638 size_t padding_len = output_len - data_len; 639 unsigned char i = 0; 640 641 output[data_len] = 0x80; 642 for( i = 1; i < padding_len; i++ ) 643 output[data_len + i] = 0x00; 644 } 645 646 static int get_one_and_zeros_padding( unsigned char *input, size_t input_len, 647 size_t *data_len ) 648 { 649 size_t i; 650 unsigned char done = 0, prev_done, bad; 651 652 if( NULL == input || NULL == data_len ) 653 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 654 655 bad = 0x80; 656 *data_len = 0; 657 for( i = input_len; i > 0; i-- ) 658 { 659 prev_done = done; 660 done |= ( input[i - 1] != 0 ); 661 *data_len |= ( i - 1 ) * ( done != prev_done ); 662 bad ^= input[i - 1] * ( done != prev_done ); 663 } 664 665 return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) ); 666 667 } 668 #endif /* MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS */ 669 670 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN) 671 /* 672 * Zeros and len padding: fill with 00 ... 00 ll, where ll is padding length 673 */ 674 static void add_zeros_and_len_padding( unsigned char *output, 675 size_t output_len, size_t data_len ) 676 { 677 size_t padding_len = output_len - data_len; 678 unsigned char i = 0; 679 680 for( i = 1; i < padding_len; i++ ) 681 output[data_len + i - 1] = 0x00; 682 output[output_len - 1] = (unsigned char) padding_len; 683 } 684 685 static int get_zeros_and_len_padding( unsigned char *input, size_t input_len, 686 size_t *data_len ) 687 { 688 size_t i, pad_idx; 689 unsigned char padding_len, bad = 0; 690 691 if( NULL == input || NULL == data_len ) 692 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 693 694 padding_len = input[input_len - 1]; 695 *data_len = input_len - padding_len; 696 697 /* Avoid logical || since it results in a branch */ 698 bad |= padding_len > input_len; 699 bad |= padding_len == 0; 700 701 /* The number of bytes checked must be independent of padding_len */ 702 pad_idx = input_len - padding_len; 703 for( i = 0; i < input_len - 1; i++ ) 704 bad |= input[i] * ( i >= pad_idx ); 705 706 return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) ); 707 } 708 #endif /* MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN */ 709 710 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS) 711 /* 712 * Zero padding: fill with 00 ... 00 713 */ 714 static void add_zeros_padding( unsigned char *output, 715 size_t output_len, size_t data_len ) 716 { 717 size_t i; 718 719 for( i = data_len; i < output_len; i++ ) 720 output[i] = 0x00; 721 } 722 723 static int get_zeros_padding( unsigned char *input, size_t input_len, 724 size_t *data_len ) 725 { 726 size_t i; 727 unsigned char done = 0, prev_done; 728 729 if( NULL == input || NULL == data_len ) 730 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 731 732 *data_len = 0; 733 for( i = input_len; i > 0; i-- ) 734 { 735 prev_done = done; 736 done |= ( input[i-1] != 0 ); 737 *data_len |= i * ( done != prev_done ); 738 } 739 740 return( 0 ); 741 } 742 #endif /* MBEDTLS_CIPHER_PADDING_ZEROS */ 743 744 /* 745 * No padding: don't pad :) 746 * 747 * There is no add_padding function (check for NULL in mbedtls_cipher_finish) 748 * but a trivial get_padding function 749 */ 750 static int get_no_padding( unsigned char *input, size_t input_len, 751 size_t *data_len ) 752 { 753 if( NULL == input || NULL == data_len ) 754 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 755 756 *data_len = input_len; 757 758 return( 0 ); 759 } 760 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */ 761 762 int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx, 763 unsigned char *output, size_t *olen ) 764 { 765 CIPHER_VALIDATE_RET( ctx != NULL ); 766 CIPHER_VALIDATE_RET( output != NULL ); 767 CIPHER_VALIDATE_RET( olen != NULL ); 768 if( ctx->cipher_info == NULL ) 769 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 770 771 *olen = 0; 772 773 if( MBEDTLS_MODE_CFB == ctx->cipher_info->mode || 774 MBEDTLS_MODE_OFB == ctx->cipher_info->mode || 775 MBEDTLS_MODE_CTR == ctx->cipher_info->mode || 776 MBEDTLS_MODE_GCM == ctx->cipher_info->mode || 777 MBEDTLS_MODE_XTS == ctx->cipher_info->mode || 778 MBEDTLS_MODE_STREAM == ctx->cipher_info->mode ) 779 { 780 return( 0 ); 781 } 782 783 if ( ( MBEDTLS_CIPHER_CHACHA20 == ctx->cipher_info->type ) || 784 ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) ) 785 { 786 return( 0 ); 787 } 788 789 if( MBEDTLS_MODE_ECB == ctx->cipher_info->mode ) 790 { 791 if( ctx->unprocessed_len != 0 ) 792 return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); 793 794 return( 0 ); 795 } 796 797 #if defined(MBEDTLS_CIPHER_MODE_CBC) 798 if( MBEDTLS_MODE_CBC == ctx->cipher_info->mode ) 799 { 800 int ret = 0; 801 802 if( MBEDTLS_ENCRYPT == ctx->operation ) 803 { 804 /* check for 'no padding' mode */ 805 if( NULL == ctx->add_padding ) 806 { 807 if( 0 != ctx->unprocessed_len ) 808 return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); 809 810 return( 0 ); 811 } 812 813 ctx->add_padding( ctx->unprocessed_data, mbedtls_cipher_get_iv_size( ctx ), 814 ctx->unprocessed_len ); 815 } 816 else if( mbedtls_cipher_get_block_size( ctx ) != ctx->unprocessed_len ) 817 { 818 /* 819 * For decrypt operations, expect a full block, 820 * or an empty block if no padding 821 */ 822 if( NULL == ctx->add_padding && 0 == ctx->unprocessed_len ) 823 return( 0 ); 824 825 return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); 826 } 827 828 /* cipher block */ 829 if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx, 830 ctx->operation, mbedtls_cipher_get_block_size( ctx ), ctx->iv, 831 ctx->unprocessed_data, output ) ) ) 832 { 833 return( ret ); 834 } 835 836 /* Set output size for decryption */ 837 if( MBEDTLS_DECRYPT == ctx->operation ) 838 return( ctx->get_padding( output, mbedtls_cipher_get_block_size( ctx ), 839 olen ) ); 840 841 /* Set output size for encryption */ 842 *olen = mbedtls_cipher_get_block_size( ctx ); 843 return( 0 ); 844 } 845 #else 846 ((void) output); 847 #endif /* MBEDTLS_CIPHER_MODE_CBC */ 848 849 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 850 } 851 852 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) 853 int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx, 854 mbedtls_cipher_padding_t mode ) 855 { 856 CIPHER_VALIDATE_RET( ctx != NULL ); 857 858 if( NULL == ctx->cipher_info || MBEDTLS_MODE_CBC != ctx->cipher_info->mode ) 859 { 860 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 861 } 862 863 switch( mode ) 864 { 865 #if defined(MBEDTLS_CIPHER_PADDING_PKCS7) 866 case MBEDTLS_PADDING_PKCS7: 867 ctx->add_padding = add_pkcs_padding; 868 ctx->get_padding = get_pkcs_padding; 869 break; 870 #endif 871 #if defined(MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS) 872 case MBEDTLS_PADDING_ONE_AND_ZEROS: 873 ctx->add_padding = add_one_and_zeros_padding; 874 ctx->get_padding = get_one_and_zeros_padding; 875 break; 876 #endif 877 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN) 878 case MBEDTLS_PADDING_ZEROS_AND_LEN: 879 ctx->add_padding = add_zeros_and_len_padding; 880 ctx->get_padding = get_zeros_and_len_padding; 881 break; 882 #endif 883 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS) 884 case MBEDTLS_PADDING_ZEROS: 885 ctx->add_padding = add_zeros_padding; 886 ctx->get_padding = get_zeros_padding; 887 break; 888 #endif 889 case MBEDTLS_PADDING_NONE: 890 ctx->add_padding = NULL; 891 ctx->get_padding = get_no_padding; 892 break; 893 894 default: 895 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 896 } 897 898 return( 0 ); 899 } 900 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */ 901 902 #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C) 903 int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx, 904 unsigned char *tag, size_t tag_len ) 905 { 906 CIPHER_VALIDATE_RET( ctx != NULL ); 907 CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL ); 908 if( ctx->cipher_info == NULL ) 909 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 910 911 if( MBEDTLS_ENCRYPT != ctx->operation ) 912 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 913 914 #if defined(MBEDTLS_GCM_C) 915 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 916 return( mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx, 917 tag, tag_len ) ); 918 #endif 919 920 #if defined(MBEDTLS_CHACHAPOLY_C) 921 if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 922 { 923 /* Don't allow truncated MAC for Poly1305 */ 924 if ( tag_len != 16U ) 925 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 926 927 return( mbedtls_chachapoly_finish( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 928 tag ) ); 929 } 930 #endif 931 932 return( 0 ); 933 } 934 935 int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx, 936 const unsigned char *tag, size_t tag_len ) 937 { 938 unsigned char check_tag[16]; 939 int ret; 940 941 CIPHER_VALIDATE_RET( ctx != NULL ); 942 CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL ); 943 if( ctx->cipher_info == NULL ) 944 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 945 946 if( MBEDTLS_DECRYPT != ctx->operation ) 947 { 948 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 949 } 950 951 #if defined(MBEDTLS_GCM_C) 952 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 953 { 954 if( tag_len > sizeof( check_tag ) ) 955 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 956 957 if( 0 != ( ret = mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx, 958 check_tag, tag_len ) ) ) 959 { 960 return( ret ); 961 } 962 963 /* Check the tag in "constant-time" */ 964 if( mbedtls_constant_time_memcmp( tag, check_tag, tag_len ) != 0 ) 965 return( MBEDTLS_ERR_CIPHER_AUTH_FAILED ); 966 967 return( 0 ); 968 } 969 #endif /* MBEDTLS_GCM_C */ 970 971 #if defined(MBEDTLS_CHACHAPOLY_C) 972 if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 973 { 974 /* Don't allow truncated MAC for Poly1305 */ 975 if ( tag_len != sizeof( check_tag ) ) 976 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 977 978 ret = mbedtls_chachapoly_finish( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 979 check_tag ); 980 if ( ret != 0 ) 981 { 982 return( ret ); 983 } 984 985 /* Check the tag in "constant-time" */ 986 if( mbedtls_constant_time_memcmp( tag, check_tag, tag_len ) != 0 ) 987 return( MBEDTLS_ERR_CIPHER_AUTH_FAILED ); 988 989 return( 0 ); 990 } 991 #endif /* MBEDTLS_CHACHAPOLY_C */ 992 993 return( 0 ); 994 } 995 #endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */ 996 997 /* 998 * Packet-oriented wrapper for non-AEAD modes 999 */ 1000 int mbedtls_cipher_crypt( mbedtls_cipher_context_t *ctx, 1001 const unsigned char *iv, size_t iv_len, 1002 const unsigned char *input, size_t ilen, 1003 unsigned char *output, size_t *olen ) 1004 { 1005 int ret; 1006 size_t finish_olen; 1007 1008 CIPHER_VALIDATE_RET( ctx != NULL ); 1009 CIPHER_VALIDATE_RET( iv_len == 0 || iv != NULL ); 1010 CIPHER_VALIDATE_RET( ilen == 0 || input != NULL ); 1011 CIPHER_VALIDATE_RET( output != NULL ); 1012 CIPHER_VALIDATE_RET( olen != NULL ); 1013 1014 if( ( ret = mbedtls_cipher_set_iv( ctx, iv, iv_len ) ) != 0 ) 1015 return( ret ); 1016 1017 if( ( ret = mbedtls_cipher_reset( ctx ) ) != 0 ) 1018 return( ret ); 1019 1020 if( ( ret = mbedtls_cipher_update( ctx, input, ilen, output, olen ) ) != 0 ) 1021 return( ret ); 1022 1023 if( ( ret = mbedtls_cipher_finish( ctx, output + *olen, &finish_olen ) ) != 0 ) 1024 return( ret ); 1025 1026 *olen += finish_olen; 1027 1028 return( 0 ); 1029 } 1030 1031 #if defined(MBEDTLS_CIPHER_MODE_AEAD) 1032 /* 1033 * Packet-oriented encryption for AEAD modes 1034 */ 1035 int mbedtls_cipher_auth_encrypt( mbedtls_cipher_context_t *ctx, 1036 const unsigned char *iv, size_t iv_len, 1037 const unsigned char *ad, size_t ad_len, 1038 const unsigned char *input, size_t ilen, 1039 unsigned char *output, size_t *olen, 1040 unsigned char *tag, size_t tag_len ) 1041 { 1042 CIPHER_VALIDATE_RET( ctx != NULL ); 1043 CIPHER_VALIDATE_RET( iv != NULL ); 1044 CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL ); 1045 CIPHER_VALIDATE_RET( ilen == 0 || input != NULL ); 1046 CIPHER_VALIDATE_RET( output != NULL ); 1047 CIPHER_VALIDATE_RET( olen != NULL ); 1048 CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL ); 1049 1050 #if defined(MBEDTLS_GCM_C) 1051 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 1052 { 1053 *olen = ilen; 1054 return( mbedtls_gcm_crypt_and_tag( ctx->cipher_ctx, MBEDTLS_GCM_ENCRYPT, ilen, 1055 iv, iv_len, ad, ad_len, input, output, 1056 tag_len, tag ) ); 1057 } 1058 #endif /* MBEDTLS_GCM_C */ 1059 #if defined(MBEDTLS_CCM_C) 1060 if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode ) 1061 { 1062 *olen = ilen; 1063 return( mbedtls_ccm_encrypt_and_tag( ctx->cipher_ctx, ilen, 1064 iv, iv_len, ad, ad_len, input, output, 1065 tag, tag_len ) ); 1066 } 1067 #endif /* MBEDTLS_CCM_C */ 1068 #if defined(MBEDTLS_CHACHAPOLY_C) 1069 if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 1070 { 1071 /* ChachaPoly has fixed length nonce and MAC (tag) */ 1072 if ( ( iv_len != ctx->cipher_info->iv_size ) || 1073 ( tag_len != 16U ) ) 1074 { 1075 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 1076 } 1077 1078 *olen = ilen; 1079 return( mbedtls_chachapoly_encrypt_and_tag( ctx->cipher_ctx, 1080 ilen, iv, ad, ad_len, input, output, tag ) ); 1081 } 1082 #endif /* MBEDTLS_CHACHAPOLY_C */ 1083 1084 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 1085 } 1086 1087 /* 1088 * Packet-oriented decryption for AEAD modes 1089 */ 1090 int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx, 1091 const unsigned char *iv, size_t iv_len, 1092 const unsigned char *ad, size_t ad_len, 1093 const unsigned char *input, size_t ilen, 1094 unsigned char *output, size_t *olen, 1095 const unsigned char *tag, size_t tag_len ) 1096 { 1097 CIPHER_VALIDATE_RET( ctx != NULL ); 1098 CIPHER_VALIDATE_RET( iv != NULL ); 1099 CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL ); 1100 CIPHER_VALIDATE_RET( ilen == 0 || input != NULL ); 1101 CIPHER_VALIDATE_RET( output != NULL ); 1102 CIPHER_VALIDATE_RET( olen != NULL ); 1103 CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL ); 1104 1105 #if defined(MBEDTLS_GCM_C) 1106 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 1107 { 1108 int ret; 1109 1110 *olen = ilen; 1111 ret = mbedtls_gcm_auth_decrypt( ctx->cipher_ctx, ilen, 1112 iv, iv_len, ad, ad_len, 1113 tag, tag_len, input, output ); 1114 1115 if( ret == MBEDTLS_ERR_GCM_AUTH_FAILED ) 1116 ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED; 1117 1118 return( ret ); 1119 } 1120 #endif /* MBEDTLS_GCM_C */ 1121 #if defined(MBEDTLS_CCM_C) 1122 if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode ) 1123 { 1124 int ret; 1125 1126 *olen = ilen; 1127 ret = mbedtls_ccm_auth_decrypt( ctx->cipher_ctx, ilen, 1128 iv, iv_len, ad, ad_len, 1129 input, output, tag, tag_len ); 1130 1131 if( ret == MBEDTLS_ERR_CCM_AUTH_FAILED ) 1132 ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED; 1133 1134 return( ret ); 1135 } 1136 #endif /* MBEDTLS_CCM_C */ 1137 #if defined(MBEDTLS_CHACHAPOLY_C) 1138 if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 1139 { 1140 int ret; 1141 1142 /* ChachaPoly has fixed length nonce and MAC (tag) */ 1143 if ( ( iv_len != ctx->cipher_info->iv_size ) || 1144 ( tag_len != 16U ) ) 1145 { 1146 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 1147 } 1148 1149 *olen = ilen; 1150 ret = mbedtls_chachapoly_auth_decrypt( ctx->cipher_ctx, ilen, 1151 iv, ad, ad_len, tag, input, output ); 1152 1153 if( ret == MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED ) 1154 ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED; 1155 1156 return( ret ); 1157 } 1158 #endif /* MBEDTLS_CHACHAPOLY_C */ 1159 1160 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 1161 } 1162 #endif /* MBEDTLS_CIPHER_MODE_AEAD */ 1163 1164 #endif /* MBEDTLS_CIPHER_C */ 1165