| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /* | ||
| 2 | * AES-CTR cipher | ||
| 3 | * Copyright (c) 2015 Eran Kornblau <erankor at gmail dot com> | ||
| 4 | * | ||
| 5 | * This file is part of FFmpeg. | ||
| 6 | * | ||
| 7 | * FFmpeg is free software; you can redistribute it and/or | ||
| 8 | * modify it under the terms of the GNU Lesser General Public | ||
| 9 | * License as published by the Free Software Foundation; either | ||
| 10 | * version 2.1 of the License, or (at your option) any later version. | ||
| 11 | * | ||
| 12 | * FFmpeg 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 GNU | ||
| 15 | * Lesser General Public License for more details. | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU Lesser General Public | ||
| 18 | * License along with FFmpeg; if not, write to the Free Software | ||
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
| 20 | */ | ||
| 21 | |||
| 22 | #include <string.h> | ||
| 23 | |||
| 24 | #include "aes_ctr.h" | ||
| 25 | #include "aes.h" | ||
| 26 | #include "aes_internal.h" | ||
| 27 | #include "intreadwrite.h" | ||
| 28 | #include "macros.h" | ||
| 29 | #include "mem.h" | ||
| 30 | #include "random_seed.h" | ||
| 31 | |||
| 32 | #define AES_BLOCK_SIZE (16) | ||
| 33 | |||
| 34 | typedef struct AVAESCTR { | ||
| 35 | DECLARE_ALIGNED(8, uint8_t, counter)[AES_BLOCK_SIZE]; | ||
| 36 | DECLARE_ALIGNED(8, uint8_t, encrypted_counter)[AES_BLOCK_SIZE]; | ||
| 37 | AVAES aes; | ||
| 38 | } AVAESCTR; | ||
| 39 | |||
| 40 | 7 | struct AVAESCTR *av_aes_ctr_alloc(void) | |
| 41 | { | ||
| 42 | 7 | return av_mallocz(sizeof(struct AVAESCTR)); | |
| 43 | } | ||
| 44 | |||
| 45 | 2 | void av_aes_ctr_set_iv(struct AVAESCTR *a, const uint8_t* iv) | |
| 46 | { | ||
| 47 | 2 | memcpy(a->counter, iv, AES_CTR_IV_SIZE); | |
| 48 | 2 | memset(a->counter + AES_CTR_IV_SIZE, 0, sizeof(a->counter) - AES_CTR_IV_SIZE); | |
| 49 | 2 | } | |
| 50 | |||
| 51 | 148 | void av_aes_ctr_set_full_iv(struct AVAESCTR *a, const uint8_t* iv) | |
| 52 | { | ||
| 53 | 148 | memcpy(a->counter, iv, sizeof(a->counter)); | |
| 54 | 148 | } | |
| 55 | |||
| 56 | 2 | const uint8_t* av_aes_ctr_get_iv(struct AVAESCTR *a) | |
| 57 | { | ||
| 58 | 2 | return a->counter; | |
| 59 | } | ||
| 60 | |||
| 61 | 1 | void av_aes_ctr_set_random_iv(struct AVAESCTR *a) | |
| 62 | { | ||
| 63 | uint32_t iv[2]; | ||
| 64 | |||
| 65 | 1 | iv[0] = av_get_random_seed(); | |
| 66 | 1 | iv[1] = av_get_random_seed(); | |
| 67 | |||
| 68 | 1 | av_aes_ctr_set_iv(a, (uint8_t*)iv); | |
| 69 | 1 | } | |
| 70 | |||
| 71 | 7 | int av_aes_ctr_init(struct AVAESCTR *a, const uint8_t *key) | |
| 72 | { | ||
| 73 | 7 | av_aes_init(&a->aes, key, 128, 0); | |
| 74 | |||
| 75 | 7 | memset(a->counter, 0, sizeof(a->counter)); | |
| 76 | |||
| 77 | 7 | return 0; | |
| 78 | } | ||
| 79 | |||
| 80 | 913 | void av_aes_ctr_free(struct AVAESCTR *a) | |
| 81 | { | ||
| 82 | 913 | av_free(a); | |
| 83 | 913 | } | |
| 84 | |||
| 85 | 5189 | static inline void av_aes_ctr_increment_be64(uint8_t* counter) | |
| 86 | { | ||
| 87 | 5189 | uint64_t c = AV_RB64A(counter) + 1; | |
| 88 | 5189 | AV_WB64A(counter, c); | |
| 89 | 5189 | } | |
| 90 | |||
| 91 | ✗ | void av_aes_ctr_increment_iv(struct AVAESCTR *a) | |
| 92 | { | ||
| 93 | ✗ | av_aes_ctr_increment_be64(a->counter); | |
| 94 | ✗ | memset(a->counter + AES_CTR_IV_SIZE, 0, sizeof(a->counter) - AES_CTR_IV_SIZE); | |
| 95 | ✗ | } | |
| 96 | |||
| 97 | 150 | void av_aes_ctr_crypt(struct AVAESCTR *a, uint8_t *dst, const uint8_t *src, int count) | |
| 98 | { | ||
| 99 |
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5219 | while (count >= AES_BLOCK_SIZE) { |
| 100 | 5069 | av_aes_crypt(&a->aes, a->encrypted_counter, a->counter, 1, NULL, 0); | |
| 101 | 5069 | av_aes_ctr_increment_be64(a->counter + 8); | |
| 102 | #if HAVE_FAST_64BIT | ||
| 103 |
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15207 | for (int len = 0; len < AES_BLOCK_SIZE; len += 8) |
| 104 | 10138 | AV_WN64(&dst[len], AV_RN64(&src[len]) ^ AV_RN64A(&a->encrypted_counter[len])); | |
| 105 | #else | ||
| 106 | for (int len = 0; len < AES_BLOCK_SIZE; len += 4) | ||
| 107 | AV_WN32(&dst[len], AV_RN32(&src[len]) ^ AV_RN32A(&a->encrypted_counter[len])); | ||
| 108 | #endif | ||
| 109 | 5069 | dst += AES_BLOCK_SIZE; | |
| 110 | 5069 | src += AES_BLOCK_SIZE; | |
| 111 | 5069 | count -= AES_BLOCK_SIZE; | |
| 112 | } | ||
| 113 | |||
| 114 |
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150 | if (count > 0) { |
| 115 | 120 | av_aes_crypt(&a->aes, a->encrypted_counter, a->counter, 1, NULL, 0); | |
| 116 | 120 | av_aes_ctr_increment_be64(a->counter + 8); | |
| 117 |
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1101 | for (int len = 0; len < count; len++) |
| 118 | 981 | dst[len] = src[len] ^ a->encrypted_counter[len]; | |
| 119 | } | ||
| 120 | 150 | } | |
| 121 |