FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavutil/aes_ctr.c
Date: 2026-04-24 19:58:39
Exec Total Coverage
Lines: 53 58 91.4%
Functions: 9 10 90.0%
Branches: 13 14 92.9%
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 int block_offset;
38 AVAES aes;
39 } AVAESCTR;
40
41 10 struct AVAESCTR *av_aes_ctr_alloc(void)
42 {
43 10 return av_mallocz(sizeof(struct AVAESCTR));
44 }
45
46 2 void av_aes_ctr_set_iv(struct AVAESCTR *a, const uint8_t* iv)
47 {
48 2 memcpy(a->counter, iv, AES_CTR_IV_SIZE);
49 2 memset(a->counter + AES_CTR_IV_SIZE, 0, sizeof(a->counter) - AES_CTR_IV_SIZE);
50 2 a->block_offset = 0;
51 2 }
52
53 294 void av_aes_ctr_set_full_iv(struct AVAESCTR *a, const uint8_t* iv)
54 {
55 294 memcpy(a->counter, iv, sizeof(a->counter));
56 294 a->block_offset = 0;
57 294 }
58
59 2 const uint8_t* av_aes_ctr_get_iv(struct AVAESCTR *a)
60 {
61 2 return a->counter;
62 }
63
64 1 void av_aes_ctr_set_random_iv(struct AVAESCTR *a)
65 {
66 uint32_t iv[2];
67
68 1 iv[0] = av_get_random_seed();
69 1 iv[1] = av_get_random_seed();
70
71 1 av_aes_ctr_set_iv(a, (uint8_t*)iv);
72 1 }
73
74 10 int av_aes_ctr_init(struct AVAESCTR *a, const uint8_t *key)
75 {
76 10 av_aes_init(&a->aes, key, 128, 0);
77
78 10 memset(a->counter, 0, sizeof(a->counter));
79 10 a->block_offset = 0;
80
81 10 return 0;
82 }
83
84 980 void av_aes_ctr_free(struct AVAESCTR *a)
85 {
86 980 av_free(a);
87 980 }
88
89 10374 static inline void av_aes_ctr_increment_be64(uint8_t* counter)
90 {
91 10374 uint64_t c = AV_RB64A(counter) + 1;
92 10374 AV_WB64A(counter, c);
93 10374 }
94
95 ✗ void av_aes_ctr_increment_iv(struct AVAESCTR *a)
96 {
97 ✗ av_aes_ctr_increment_be64(a->counter);
98 ✗ memset(a->counter + AES_CTR_IV_SIZE, 0, sizeof(a->counter) - AES_CTR_IV_SIZE);
99 ✗ a->block_offset = 0;
100 ✗ }
101
102 312 void av_aes_ctr_crypt(struct AVAESCTR *a, uint8_t *dst, const uint8_t *src, int count)
103 {
104
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 312 if (a->block_offset && count > 0) {
105 16 int left = FFMIN(count, AES_BLOCK_SIZE - a->block_offset);
106
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 89 for (int len = 0; len < left; len++)
107 73 dst[len] = src[len] ^ a->encrypted_counter[a->block_offset++];
108 16 a->block_offset &= AES_BLOCK_SIZE - 1;
109 16 dst += left;
110 16 src += left;
111 16 count -= left;
112 }
113
114
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 10444 while (count >= AES_BLOCK_SIZE) {
115 10132 av_aes_crypt(&a->aes, a->encrypted_counter, a->counter, 1, NULL, 0);
116 10132 av_aes_ctr_increment_be64(a->counter + 8);
117 #if HAVE_FAST_64BIT
118
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 30396 for (int len = 0; len < AES_BLOCK_SIZE; len += 8)
119 20264 AV_WN64(&dst[len], AV_RN64(&src[len]) ^ AV_RN64A(&a->encrypted_counter[len]));
120 #else
121 for (int len = 0; len < AES_BLOCK_SIZE; len += 4)
122 AV_WN32(&dst[len], AV_RN32(&src[len]) ^ AV_RN32A(&a->encrypted_counter[len]));
123 #endif
124 10132 dst += AES_BLOCK_SIZE;
125 10132 src += AES_BLOCK_SIZE;
126 10132 count -= AES_BLOCK_SIZE;
127 }
128
129
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 312 if (count > 0) {
130 242 av_aes_crypt(&a->aes, a->encrypted_counter, a->counter, 1, NULL, 0);
131 242 av_aes_ctr_increment_be64(a->counter + 8);
132
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 2227 for (int len = 0; len < count; len++)
133 1985 dst[len] = src[len] ^ a->encrypted_counter[a->block_offset++];
134 }
135 312 }
136