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_clone( mbedtls_cipher_context_t *dst, 183 const mbedtls_cipher_context_t *src ) 184 { 185 if( dst == NULL || dst->cipher_info == NULL || 186 src == NULL || src->cipher_info == NULL) 187 { 188 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 189 } 190 191 dst->cipher_info = src->cipher_info; 192 dst->key_bitlen = src->key_bitlen; 193 dst->operation = src->operation; 194 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) 195 dst->add_padding = src->add_padding; 196 dst->get_padding = src->get_padding; 197 #endif 198 memcpy( dst->unprocessed_data, src->unprocessed_data, MBEDTLS_MAX_BLOCK_LENGTH ); 199 dst->unprocessed_len = src->unprocessed_len; 200 memcpy( dst->iv, src->iv, MBEDTLS_MAX_IV_LENGTH ); 201 dst->iv_size = src->iv_size; 202 if( dst->cipher_info->base->ctx_clone_func ) 203 dst->cipher_info->base->ctx_clone_func( dst->cipher_ctx, src->cipher_ctx ); 204 205 #if defined(MBEDTLS_CMAC_C) 206 if( dst->cmac_ctx != NULL && src->cmac_ctx != NULL ) 207 memcpy( dst->cmac_ctx, src->cmac_ctx, sizeof( mbedtls_cmac_context_t ) ); 208 #endif 209 return( 0 ); 210 } 211 212 int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx, const mbedtls_cipher_info_t *cipher_info ) 213 { 214 CIPHER_VALIDATE_RET( ctx != NULL ); 215 if( cipher_info == NULL ) 216 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 217 218 memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) ); 219 220 if( NULL == ( ctx->cipher_ctx = cipher_info->base->ctx_alloc_func() ) ) 221 return( MBEDTLS_ERR_CIPHER_ALLOC_FAILED ); 222 223 ctx->cipher_info = cipher_info; 224 225 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) 226 /* 227 * Ignore possible errors caused by a cipher mode that doesn't use padding 228 */ 229 #if defined(MBEDTLS_CIPHER_PADDING_PKCS7) 230 (void) mbedtls_cipher_set_padding_mode( ctx, MBEDTLS_PADDING_PKCS7 ); 231 #else 232 (void) mbedtls_cipher_set_padding_mode( ctx, MBEDTLS_PADDING_NONE ); 233 #endif 234 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */ 235 236 return( 0 ); 237 } 238 239 int mbedtls_cipher_setup_info( mbedtls_cipher_context_t *ctx, const mbedtls_cipher_info_t *cipher_info ) 240 { 241 if( NULL == cipher_info || NULL == ctx ) 242 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 243 244 ctx->cipher_info = cipher_info; 245 return( 0 ); 246 } 247 248 int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx, 249 const unsigned char *key, 250 int key_bitlen, 251 const mbedtls_operation_t operation ) 252 { 253 CIPHER_VALIDATE_RET( ctx != NULL ); 254 CIPHER_VALIDATE_RET( key != NULL ); 255 CIPHER_VALIDATE_RET( operation == MBEDTLS_ENCRYPT || 256 operation == MBEDTLS_DECRYPT ); 257 if( ctx->cipher_info == NULL ) 258 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 259 260 if( ( ctx->cipher_info->flags & MBEDTLS_CIPHER_VARIABLE_KEY_LEN ) == 0 && 261 (int) ctx->cipher_info->key_bitlen != key_bitlen ) 262 { 263 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 264 } 265 266 ctx->key_bitlen = key_bitlen; 267 ctx->operation = operation; 268 269 /* 270 * For OFB, CFB and CTR mode always use the encryption key schedule 271 */ 272 if( MBEDTLS_ENCRYPT == operation || 273 MBEDTLS_MODE_CFB == ctx->cipher_info->mode || 274 MBEDTLS_MODE_OFB == ctx->cipher_info->mode || 275 MBEDTLS_MODE_CTR == ctx->cipher_info->mode ) 276 { 277 return( ctx->cipher_info->base->setkey_enc_func( ctx->cipher_ctx, key, 278 ctx->key_bitlen ) ); 279 } 280 281 if( MBEDTLS_DECRYPT == operation ) 282 return( ctx->cipher_info->base->setkey_dec_func( ctx->cipher_ctx, key, 283 ctx->key_bitlen ) ); 284 285 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 286 } 287 288 int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx, 289 const unsigned char *iv, 290 size_t iv_len ) 291 { 292 size_t actual_iv_size; 293 294 CIPHER_VALIDATE_RET( ctx != NULL ); 295 CIPHER_VALIDATE_RET( iv_len == 0 || iv != NULL ); 296 if( ctx->cipher_info == NULL ) 297 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 298 299 /* avoid buffer overflow in ctx->iv */ 300 if( iv_len > MBEDTLS_MAX_IV_LENGTH ) 301 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 302 303 if( ( ctx->cipher_info->flags & MBEDTLS_CIPHER_VARIABLE_IV_LEN ) != 0 ) 304 actual_iv_size = iv_len; 305 else 306 { 307 actual_iv_size = ctx->cipher_info->iv_size; 308 309 /* avoid reading past the end of input buffer */ 310 if( actual_iv_size > iv_len ) 311 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 312 } 313 314 #if defined(MBEDTLS_CHACHA20_C) 315 if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20 ) 316 { 317 if ( 0 != mbedtls_chacha20_starts( (mbedtls_chacha20_context*)ctx->cipher_ctx, 318 iv, 319 0U ) ) /* Initial counter value */ 320 { 321 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 322 } 323 } 324 #endif 325 326 if ( actual_iv_size != 0 ) 327 { 328 memcpy( ctx->iv, iv, actual_iv_size ); 329 ctx->iv_size = actual_iv_size; 330 } 331 332 return( 0 ); 333 } 334 335 int mbedtls_cipher_reset( mbedtls_cipher_context_t *ctx ) 336 { 337 CIPHER_VALIDATE_RET( ctx != NULL ); 338 if( ctx->cipher_info == NULL ) 339 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 340 341 ctx->unprocessed_len = 0; 342 343 return( 0 ); 344 } 345 346 #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C) 347 int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx, 348 const unsigned char *ad, size_t ad_len ) 349 { 350 CIPHER_VALIDATE_RET( ctx != NULL ); 351 CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL ); 352 if( ctx->cipher_info == NULL ) 353 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 354 355 #if defined(MBEDTLS_GCM_C) 356 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 357 { 358 return( mbedtls_gcm_starts( (mbedtls_gcm_context *) ctx->cipher_ctx, ctx->operation, 359 ctx->iv, ctx->iv_size, ad, ad_len ) ); 360 } 361 #endif 362 363 #if defined(MBEDTLS_CHACHAPOLY_C) 364 if (MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 365 { 366 int result; 367 mbedtls_chachapoly_mode_t mode; 368 369 mode = ( ctx->operation == MBEDTLS_ENCRYPT ) 370 ? MBEDTLS_CHACHAPOLY_ENCRYPT 371 : MBEDTLS_CHACHAPOLY_DECRYPT; 372 373 result = mbedtls_chachapoly_starts( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 374 ctx->iv, 375 mode ); 376 if ( result != 0 ) 377 return( result ); 378 379 return( mbedtls_chachapoly_update_aad( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 380 ad, ad_len ) ); 381 } 382 #endif 383 384 return( 0 ); 385 } 386 #endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */ 387 388 int mbedtls_cipher_update( mbedtls_cipher_context_t *ctx, const unsigned char *input, 389 size_t ilen, unsigned char *output, size_t *olen ) 390 { 391 int ret; 392 size_t block_size; 393 394 CIPHER_VALIDATE_RET( ctx != NULL ); 395 CIPHER_VALIDATE_RET( ilen == 0 || input != NULL ); 396 CIPHER_VALIDATE_RET( output != NULL ); 397 CIPHER_VALIDATE_RET( olen != NULL ); 398 if( ctx->cipher_info == NULL ) 399 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 400 401 *olen = 0; 402 block_size = mbedtls_cipher_get_block_size( ctx ); 403 404 if( ctx->cipher_info->mode == MBEDTLS_MODE_ECB ) 405 { 406 if( ilen != block_size ) 407 return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); 408 409 *olen = ilen; 410 411 if( 0 != ( ret = ctx->cipher_info->base->ecb_func( ctx->cipher_ctx, 412 ctx->operation, input, output ) ) ) 413 { 414 return( ret ); 415 } 416 417 return( 0 ); 418 } 419 420 #if defined(MBEDTLS_GCM_C) 421 if( ctx->cipher_info->mode == MBEDTLS_MODE_GCM ) 422 { 423 *olen = ilen; 424 return( mbedtls_gcm_update( (mbedtls_gcm_context *) ctx->cipher_ctx, ilen, input, 425 output ) ); 426 } 427 #endif 428 429 #if defined(MBEDTLS_CHACHAPOLY_C) 430 if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20_POLY1305 ) 431 { 432 *olen = ilen; 433 return( mbedtls_chachapoly_update( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 434 ilen, input, output ) ); 435 } 436 #endif 437 438 if ( 0 == block_size ) 439 { 440 return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT ); 441 } 442 443 if( input == output && 444 ( ctx->unprocessed_len != 0 || ilen % block_size ) ) 445 { 446 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 447 } 448 449 #if defined(MBEDTLS_CIPHER_MODE_CBC) 450 if( ctx->cipher_info->mode == MBEDTLS_MODE_CBC ) 451 { 452 size_t copy_len = 0; 453 454 /* 455 * If there is not enough data for a full block, cache it. 456 */ 457 if( ( ctx->operation == MBEDTLS_DECRYPT && NULL != ctx->add_padding && 458 ilen <= block_size - ctx->unprocessed_len ) || 459 ( ctx->operation == MBEDTLS_DECRYPT && NULL == ctx->add_padding && 460 ilen < block_size - ctx->unprocessed_len ) || 461 ( ctx->operation == MBEDTLS_ENCRYPT && 462 ilen < block_size - ctx->unprocessed_len ) ) 463 { 464 memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input, 465 ilen ); 466 467 ctx->unprocessed_len += ilen; 468 return( 0 ); 469 } 470 471 /* 472 * Process cached data first 473 */ 474 if( 0 != ctx->unprocessed_len ) 475 { 476 copy_len = block_size - ctx->unprocessed_len; 477 478 memcpy( &( ctx->unprocessed_data[ctx->unprocessed_len] ), input, 479 copy_len ); 480 481 if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx, 482 ctx->operation, block_size, ctx->iv, 483 ctx->unprocessed_data, output ) ) ) 484 { 485 return( ret ); 486 } 487 488 *olen += block_size; 489 output += block_size; 490 ctx->unprocessed_len = 0; 491 492 input += copy_len; 493 ilen -= copy_len; 494 } 495 496 /* 497 * Cache final, incomplete block 498 */ 499 if( 0 != ilen ) 500 { 501 if( 0 == block_size ) 502 { 503 return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT ); 504 } 505 506 /* Encryption: only cache partial blocks 507 * Decryption w/ padding: always keep at least one whole block 508 * Decryption w/o padding: only cache partial blocks 509 */ 510 copy_len = ilen % block_size; 511 if( copy_len == 0 && 512 ctx->operation == MBEDTLS_DECRYPT && 513 NULL != ctx->add_padding) 514 { 515 copy_len = block_size; 516 } 517 518 memcpy( ctx->unprocessed_data, &( input[ilen - copy_len] ), 519 copy_len ); 520 521 ctx->unprocessed_len += copy_len; 522 ilen -= copy_len; 523 } 524 525 /* 526 * Process remaining full blocks 527 */ 528 if( ilen ) 529 { 530 if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx, 531 ctx->operation, ilen, ctx->iv, input, output ) ) ) 532 { 533 return( ret ); 534 } 535 536 *olen += ilen; 537 } 538 539 return( 0 ); 540 } 541 #endif /* MBEDTLS_CIPHER_MODE_CBC */ 542 543 #if defined(MBEDTLS_CIPHER_MODE_CFB) 544 if( ctx->cipher_info->mode == MBEDTLS_MODE_CFB ) 545 { 546 if( 0 != ( ret = ctx->cipher_info->base->cfb_func( ctx->cipher_ctx, 547 ctx->operation, ilen, &ctx->unprocessed_len, ctx->iv, 548 input, output ) ) ) 549 { 550 return( ret ); 551 } 552 553 *olen = ilen; 554 555 return( 0 ); 556 } 557 #endif /* MBEDTLS_CIPHER_MODE_CFB */ 558 559 #if defined(MBEDTLS_CIPHER_MODE_OFB) 560 if( ctx->cipher_info->mode == MBEDTLS_MODE_OFB ) 561 { 562 if( 0 != ( ret = ctx->cipher_info->base->ofb_func( ctx->cipher_ctx, 563 ilen, &ctx->unprocessed_len, ctx->iv, input, output ) ) ) 564 { 565 return( ret ); 566 } 567 568 *olen = ilen; 569 570 return( 0 ); 571 } 572 #endif /* MBEDTLS_CIPHER_MODE_OFB */ 573 574 #if defined(MBEDTLS_CIPHER_MODE_CTR) 575 if( ctx->cipher_info->mode == MBEDTLS_MODE_CTR ) 576 { 577 if( 0 != ( ret = ctx->cipher_info->base->ctr_func( ctx->cipher_ctx, 578 ilen, &ctx->unprocessed_len, ctx->iv, 579 ctx->unprocessed_data, input, output ) ) ) 580 { 581 return( ret ); 582 } 583 584 *olen = ilen; 585 586 return( 0 ); 587 } 588 #endif /* MBEDTLS_CIPHER_MODE_CTR */ 589 590 #if defined(MBEDTLS_CIPHER_MODE_XTS) 591 if( ctx->cipher_info->mode == MBEDTLS_MODE_XTS ) 592 { 593 if( ctx->unprocessed_len > 0 ) { 594 /* We can only process an entire data unit at a time. */ 595 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 596 } 597 598 ret = ctx->cipher_info->base->xts_func( ctx->cipher_ctx, 599 ctx->operation, ilen, ctx->iv, input, output ); 600 if( ret != 0 ) 601 { 602 return( ret ); 603 } 604 605 *olen = ilen; 606 607 return( 0 ); 608 } 609 #endif /* MBEDTLS_CIPHER_MODE_XTS */ 610 611 #if defined(MBEDTLS_CIPHER_MODE_STREAM) 612 if( ctx->cipher_info->mode == MBEDTLS_MODE_STREAM ) 613 { 614 if( 0 != ( ret = ctx->cipher_info->base->stream_func( ctx->cipher_ctx, 615 ilen, input, output ) ) ) 616 { 617 return( ret ); 618 } 619 620 *olen = ilen; 621 622 return( 0 ); 623 } 624 #endif /* MBEDTLS_CIPHER_MODE_STREAM */ 625 626 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 627 } 628 629 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) 630 #if defined(MBEDTLS_CIPHER_PADDING_PKCS7) 631 /* 632 * PKCS7 (and PKCS5) padding: fill with ll bytes, with ll = padding_len 633 */ 634 static void add_pkcs_padding( unsigned char *output, size_t output_len, 635 size_t data_len ) 636 { 637 size_t padding_len = output_len - data_len; 638 unsigned char i; 639 640 for( i = 0; i < padding_len; i++ ) 641 output[data_len + i] = (unsigned char) padding_len; 642 } 643 644 static int get_pkcs_padding( unsigned char *input, size_t input_len, 645 size_t *data_len ) 646 { 647 size_t i, pad_idx; 648 unsigned char padding_len, bad = 0; 649 650 if( NULL == input || NULL == data_len ) 651 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 652 653 padding_len = input[input_len - 1]; 654 *data_len = input_len - padding_len; 655 656 /* Avoid logical || since it results in a branch */ 657 bad |= padding_len > input_len; 658 bad |= padding_len == 0; 659 660 /* The number of bytes checked must be independent of padding_len, 661 * so pick input_len, which is usually 8 or 16 (one block) */ 662 pad_idx = input_len - padding_len; 663 for( i = 0; i < input_len; i++ ) 664 bad |= ( input[i] ^ padding_len ) * ( i >= pad_idx ); 665 666 return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) ); 667 } 668 #endif /* MBEDTLS_CIPHER_PADDING_PKCS7 */ 669 670 #if defined(MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS) 671 /* 672 * One and zeros padding: fill with 80 00 ... 00 673 */ 674 static void add_one_and_zeros_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 output[data_len] = 0x80; 681 for( i = 1; i < padding_len; i++ ) 682 output[data_len + i] = 0x00; 683 } 684 685 static int get_one_and_zeros_padding( unsigned char *input, size_t input_len, 686 size_t *data_len ) 687 { 688 size_t i; 689 unsigned char done = 0, prev_done, bad; 690 691 if( NULL == input || NULL == data_len ) 692 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 693 694 bad = 0x80; 695 *data_len = 0; 696 for( i = input_len; i > 0; i-- ) 697 { 698 prev_done = done; 699 done |= ( input[i - 1] != 0 ); 700 *data_len |= ( i - 1 ) * ( done != prev_done ); 701 bad ^= input[i - 1] * ( done != prev_done ); 702 } 703 704 return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) ); 705 706 } 707 #endif /* MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS */ 708 709 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN) 710 /* 711 * Zeros and len padding: fill with 00 ... 00 ll, where ll is padding length 712 */ 713 static void add_zeros_and_len_padding( unsigned char *output, 714 size_t output_len, size_t data_len ) 715 { 716 size_t padding_len = output_len - data_len; 717 unsigned char i = 0; 718 719 for( i = 1; i < padding_len; i++ ) 720 output[data_len + i - 1] = 0x00; 721 output[output_len - 1] = (unsigned char) padding_len; 722 } 723 724 static int get_zeros_and_len_padding( unsigned char *input, size_t input_len, 725 size_t *data_len ) 726 { 727 size_t i, pad_idx; 728 unsigned char padding_len, bad = 0; 729 730 if( NULL == input || NULL == data_len ) 731 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 732 733 padding_len = input[input_len - 1]; 734 *data_len = input_len - padding_len; 735 736 /* Avoid logical || since it results in a branch */ 737 bad |= padding_len > input_len; 738 bad |= padding_len == 0; 739 740 /* The number of bytes checked must be independent of padding_len */ 741 pad_idx = input_len - padding_len; 742 for( i = 0; i < input_len - 1; i++ ) 743 bad |= input[i] * ( i >= pad_idx ); 744 745 return( MBEDTLS_ERR_CIPHER_INVALID_PADDING * ( bad != 0 ) ); 746 } 747 #endif /* MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN */ 748 749 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS) 750 /* 751 * Zero padding: fill with 00 ... 00 752 */ 753 static void add_zeros_padding( unsigned char *output, 754 size_t output_len, size_t data_len ) 755 { 756 size_t i; 757 758 for( i = data_len; i < output_len; i++ ) 759 output[i] = 0x00; 760 } 761 762 static int get_zeros_padding( unsigned char *input, size_t input_len, 763 size_t *data_len ) 764 { 765 size_t i; 766 unsigned char done = 0, prev_done; 767 768 if( NULL == input || NULL == data_len ) 769 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 770 771 *data_len = 0; 772 for( i = input_len; i > 0; i-- ) 773 { 774 prev_done = done; 775 done |= ( input[i-1] != 0 ); 776 *data_len |= i * ( done != prev_done ); 777 } 778 779 return( 0 ); 780 } 781 #endif /* MBEDTLS_CIPHER_PADDING_ZEROS */ 782 783 /* 784 * No padding: don't pad :) 785 * 786 * There is no add_padding function (check for NULL in mbedtls_cipher_finish) 787 * but a trivial get_padding function 788 */ 789 static int get_no_padding( unsigned char *input, size_t input_len, 790 size_t *data_len ) 791 { 792 if( NULL == input || NULL == data_len ) 793 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 794 795 *data_len = input_len; 796 797 return( 0 ); 798 } 799 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */ 800 801 int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx, 802 unsigned char *output, size_t *olen ) 803 { 804 CIPHER_VALIDATE_RET( ctx != NULL ); 805 CIPHER_VALIDATE_RET( output != NULL ); 806 CIPHER_VALIDATE_RET( olen != NULL ); 807 if( ctx->cipher_info == NULL ) 808 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 809 810 *olen = 0; 811 812 if( MBEDTLS_MODE_CFB == ctx->cipher_info->mode || 813 MBEDTLS_MODE_OFB == ctx->cipher_info->mode || 814 MBEDTLS_MODE_CTR == ctx->cipher_info->mode || 815 MBEDTLS_MODE_GCM == ctx->cipher_info->mode || 816 MBEDTLS_MODE_XTS == ctx->cipher_info->mode || 817 MBEDTLS_MODE_STREAM == ctx->cipher_info->mode ) 818 { 819 return( 0 ); 820 } 821 822 if ( ( MBEDTLS_CIPHER_CHACHA20 == ctx->cipher_info->type ) || 823 ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) ) 824 { 825 return( 0 ); 826 } 827 828 if( MBEDTLS_MODE_ECB == ctx->cipher_info->mode ) 829 { 830 if( ctx->unprocessed_len != 0 ) 831 return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); 832 833 return( 0 ); 834 } 835 836 #if defined(MBEDTLS_CIPHER_MODE_CBC) 837 if( MBEDTLS_MODE_CBC == ctx->cipher_info->mode ) 838 { 839 int ret = 0; 840 841 if( MBEDTLS_ENCRYPT == ctx->operation ) 842 { 843 /* check for 'no padding' mode */ 844 if( NULL == ctx->add_padding ) 845 { 846 if( 0 != ctx->unprocessed_len ) 847 return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); 848 849 return( 0 ); 850 } 851 852 ctx->add_padding( ctx->unprocessed_data, mbedtls_cipher_get_iv_size( ctx ), 853 ctx->unprocessed_len ); 854 } 855 else if( mbedtls_cipher_get_block_size( ctx ) != ctx->unprocessed_len ) 856 { 857 /* 858 * For decrypt operations, expect a full block, 859 * or an empty block if no padding 860 */ 861 if( NULL == ctx->add_padding && 0 == ctx->unprocessed_len ) 862 return( 0 ); 863 864 return( MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED ); 865 } 866 867 /* cipher block */ 868 if( 0 != ( ret = ctx->cipher_info->base->cbc_func( ctx->cipher_ctx, 869 ctx->operation, mbedtls_cipher_get_block_size( ctx ), ctx->iv, 870 ctx->unprocessed_data, output ) ) ) 871 { 872 return( ret ); 873 } 874 875 /* Set output size for decryption */ 876 if( MBEDTLS_DECRYPT == ctx->operation ) 877 return( ctx->get_padding( output, mbedtls_cipher_get_block_size( ctx ), 878 olen ) ); 879 880 /* Set output size for encryption */ 881 *olen = mbedtls_cipher_get_block_size( ctx ); 882 return( 0 ); 883 } 884 #else 885 ((void) output); 886 #endif /* MBEDTLS_CIPHER_MODE_CBC */ 887 888 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 889 } 890 891 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING) 892 int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx, 893 mbedtls_cipher_padding_t mode ) 894 { 895 CIPHER_VALIDATE_RET( ctx != NULL ); 896 897 if( NULL == ctx->cipher_info || MBEDTLS_MODE_CBC != ctx->cipher_info->mode ) 898 { 899 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 900 } 901 902 switch( mode ) 903 { 904 #if defined(MBEDTLS_CIPHER_PADDING_PKCS7) 905 case MBEDTLS_PADDING_PKCS7: 906 ctx->add_padding = add_pkcs_padding; 907 ctx->get_padding = get_pkcs_padding; 908 break; 909 #endif 910 #if defined(MBEDTLS_CIPHER_PADDING_ONE_AND_ZEROS) 911 case MBEDTLS_PADDING_ONE_AND_ZEROS: 912 ctx->add_padding = add_one_and_zeros_padding; 913 ctx->get_padding = get_one_and_zeros_padding; 914 break; 915 #endif 916 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS_AND_LEN) 917 case MBEDTLS_PADDING_ZEROS_AND_LEN: 918 ctx->add_padding = add_zeros_and_len_padding; 919 ctx->get_padding = get_zeros_and_len_padding; 920 break; 921 #endif 922 #if defined(MBEDTLS_CIPHER_PADDING_ZEROS) 923 case MBEDTLS_PADDING_ZEROS: 924 ctx->add_padding = add_zeros_padding; 925 ctx->get_padding = get_zeros_padding; 926 break; 927 #endif 928 case MBEDTLS_PADDING_NONE: 929 ctx->add_padding = NULL; 930 ctx->get_padding = get_no_padding; 931 break; 932 933 default: 934 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 935 } 936 937 return( 0 ); 938 } 939 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */ 940 941 #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C) 942 int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx, 943 unsigned char *tag, size_t tag_len ) 944 { 945 CIPHER_VALIDATE_RET( ctx != NULL ); 946 CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL ); 947 if( ctx->cipher_info == NULL ) 948 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 949 950 if( MBEDTLS_ENCRYPT != ctx->operation ) 951 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 952 953 #if defined(MBEDTLS_GCM_C) 954 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 955 return( mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx, 956 tag, tag_len ) ); 957 #endif 958 959 #if defined(MBEDTLS_CHACHAPOLY_C) 960 if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 961 { 962 /* Don't allow truncated MAC for Poly1305 */ 963 if ( tag_len != 16U ) 964 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 965 966 return( mbedtls_chachapoly_finish( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 967 tag ) ); 968 } 969 #endif 970 971 return( 0 ); 972 } 973 974 int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx, 975 const unsigned char *tag, size_t tag_len ) 976 { 977 unsigned char check_tag[16]; 978 int ret; 979 980 CIPHER_VALIDATE_RET( ctx != NULL ); 981 CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL ); 982 if( ctx->cipher_info == NULL ) 983 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 984 985 if( MBEDTLS_DECRYPT != ctx->operation ) 986 { 987 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 988 } 989 990 #if defined(MBEDTLS_GCM_C) 991 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 992 { 993 if( tag_len > sizeof( check_tag ) ) 994 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 995 996 if( 0 != ( ret = mbedtls_gcm_finish( (mbedtls_gcm_context *) ctx->cipher_ctx, 997 check_tag, tag_len ) ) ) 998 { 999 return( ret ); 1000 } 1001 1002 /* Check the tag in "constant-time" */ 1003 if( mbedtls_constant_time_memcmp( tag, check_tag, tag_len ) != 0 ) 1004 return( MBEDTLS_ERR_CIPHER_AUTH_FAILED ); 1005 1006 return( 0 ); 1007 } 1008 #endif /* MBEDTLS_GCM_C */ 1009 1010 #if defined(MBEDTLS_CHACHAPOLY_C) 1011 if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 1012 { 1013 /* Don't allow truncated MAC for Poly1305 */ 1014 if ( tag_len != sizeof( check_tag ) ) 1015 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 1016 1017 ret = mbedtls_chachapoly_finish( (mbedtls_chachapoly_context*) ctx->cipher_ctx, 1018 check_tag ); 1019 if ( ret != 0 ) 1020 { 1021 return( ret ); 1022 } 1023 1024 /* Check the tag in "constant-time" */ 1025 if( mbedtls_constant_time_memcmp( tag, check_tag, tag_len ) != 0 ) 1026 return( MBEDTLS_ERR_CIPHER_AUTH_FAILED ); 1027 1028 return( 0 ); 1029 } 1030 #endif /* MBEDTLS_CHACHAPOLY_C */ 1031 1032 return( 0 ); 1033 } 1034 #endif /* MBEDTLS_GCM_C || MBEDTLS_CHACHAPOLY_C */ 1035 1036 /* 1037 * Packet-oriented wrapper for non-AEAD modes 1038 */ 1039 int mbedtls_cipher_crypt( mbedtls_cipher_context_t *ctx, 1040 const unsigned char *iv, size_t iv_len, 1041 const unsigned char *input, size_t ilen, 1042 unsigned char *output, size_t *olen ) 1043 { 1044 int ret; 1045 size_t finish_olen; 1046 1047 CIPHER_VALIDATE_RET( ctx != NULL ); 1048 CIPHER_VALIDATE_RET( iv_len == 0 || iv != NULL ); 1049 CIPHER_VALIDATE_RET( ilen == 0 || input != NULL ); 1050 CIPHER_VALIDATE_RET( output != NULL ); 1051 CIPHER_VALIDATE_RET( olen != NULL ); 1052 1053 if( ( ret = mbedtls_cipher_set_iv( ctx, iv, iv_len ) ) != 0 ) 1054 return( ret ); 1055 1056 if( ( ret = mbedtls_cipher_reset( ctx ) ) != 0 ) 1057 return( ret ); 1058 1059 if( ( ret = mbedtls_cipher_update( ctx, input, ilen, output, olen ) ) != 0 ) 1060 return( ret ); 1061 1062 if( ( ret = mbedtls_cipher_finish( ctx, output + *olen, &finish_olen ) ) != 0 ) 1063 return( ret ); 1064 1065 *olen += finish_olen; 1066 1067 return( 0 ); 1068 } 1069 1070 #if defined(MBEDTLS_CIPHER_MODE_AEAD) 1071 /* 1072 * Packet-oriented encryption for AEAD modes 1073 */ 1074 int mbedtls_cipher_auth_encrypt( mbedtls_cipher_context_t *ctx, 1075 const unsigned char *iv, size_t iv_len, 1076 const unsigned char *ad, size_t ad_len, 1077 const unsigned char *input, size_t ilen, 1078 unsigned char *output, size_t *olen, 1079 unsigned char *tag, size_t tag_len ) 1080 { 1081 CIPHER_VALIDATE_RET( ctx != NULL ); 1082 CIPHER_VALIDATE_RET( iv != NULL ); 1083 CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL ); 1084 CIPHER_VALIDATE_RET( ilen == 0 || input != NULL ); 1085 CIPHER_VALIDATE_RET( output != NULL ); 1086 CIPHER_VALIDATE_RET( olen != NULL ); 1087 CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL ); 1088 1089 #if defined(MBEDTLS_GCM_C) 1090 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 1091 { 1092 *olen = ilen; 1093 return( mbedtls_gcm_crypt_and_tag( ctx->cipher_ctx, MBEDTLS_GCM_ENCRYPT, ilen, 1094 iv, iv_len, ad, ad_len, input, output, 1095 tag_len, tag ) ); 1096 } 1097 #endif /* MBEDTLS_GCM_C */ 1098 #if defined(MBEDTLS_CCM_C) 1099 if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode ) 1100 { 1101 *olen = ilen; 1102 return( mbedtls_ccm_encrypt_and_tag( ctx->cipher_ctx, ilen, 1103 iv, iv_len, ad, ad_len, input, output, 1104 tag, tag_len ) ); 1105 } 1106 #endif /* MBEDTLS_CCM_C */ 1107 #if defined(MBEDTLS_CHACHAPOLY_C) 1108 if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 1109 { 1110 /* ChachaPoly has fixed length nonce and MAC (tag) */ 1111 if ( ( iv_len != ctx->cipher_info->iv_size ) || 1112 ( tag_len != 16U ) ) 1113 { 1114 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 1115 } 1116 1117 *olen = ilen; 1118 return( mbedtls_chachapoly_encrypt_and_tag( ctx->cipher_ctx, 1119 ilen, iv, ad, ad_len, input, output, tag ) ); 1120 } 1121 #endif /* MBEDTLS_CHACHAPOLY_C */ 1122 1123 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 1124 } 1125 1126 /* 1127 * Packet-oriented decryption for AEAD modes 1128 */ 1129 int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx, 1130 const unsigned char *iv, size_t iv_len, 1131 const unsigned char *ad, size_t ad_len, 1132 const unsigned char *input, size_t ilen, 1133 unsigned char *output, size_t *olen, 1134 const unsigned char *tag, size_t tag_len ) 1135 { 1136 CIPHER_VALIDATE_RET( ctx != NULL ); 1137 CIPHER_VALIDATE_RET( iv != NULL ); 1138 CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL ); 1139 CIPHER_VALIDATE_RET( ilen == 0 || input != NULL ); 1140 CIPHER_VALIDATE_RET( output != NULL ); 1141 CIPHER_VALIDATE_RET( olen != NULL ); 1142 CIPHER_VALIDATE_RET( tag_len == 0 || tag != NULL ); 1143 1144 #if defined(MBEDTLS_GCM_C) 1145 if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode ) 1146 { 1147 int ret; 1148 1149 *olen = ilen; 1150 ret = mbedtls_gcm_auth_decrypt( ctx->cipher_ctx, ilen, 1151 iv, iv_len, ad, ad_len, 1152 tag, tag_len, input, output ); 1153 1154 if( ret == MBEDTLS_ERR_GCM_AUTH_FAILED ) 1155 ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED; 1156 1157 return( ret ); 1158 } 1159 #endif /* MBEDTLS_GCM_C */ 1160 #if defined(MBEDTLS_CCM_C) 1161 if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode ) 1162 { 1163 int ret; 1164 1165 *olen = ilen; 1166 ret = mbedtls_ccm_auth_decrypt( ctx->cipher_ctx, ilen, 1167 iv, iv_len, ad, ad_len, 1168 input, output, tag, tag_len ); 1169 1170 if( ret == MBEDTLS_ERR_CCM_AUTH_FAILED ) 1171 ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED; 1172 1173 return( ret ); 1174 } 1175 #endif /* MBEDTLS_CCM_C */ 1176 #if defined(MBEDTLS_CHACHAPOLY_C) 1177 if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type ) 1178 { 1179 int ret; 1180 1181 /* ChachaPoly has fixed length nonce and MAC (tag) */ 1182 if ( ( iv_len != ctx->cipher_info->iv_size ) || 1183 ( tag_len != 16U ) ) 1184 { 1185 return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA ); 1186 } 1187 1188 *olen = ilen; 1189 ret = mbedtls_chachapoly_auth_decrypt( ctx->cipher_ctx, ilen, 1190 iv, ad, ad_len, tag, input, output ); 1191 1192 if( ret == MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED ) 1193 ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED; 1194 1195 return( ret ); 1196 } 1197 #endif /* MBEDTLS_CHACHAPOLY_C */ 1198 1199 return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE ); 1200 } 1201 #endif /* MBEDTLS_CIPHER_MODE_AEAD */ 1202 1203 #endif /* MBEDTLS_CIPHER_C */ 1204