FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavutil/aes.c
Date: 2024-02-16 17:37:06
Exec Total Coverage
Lines: 130 137 94.9%
Functions: 13 13 100.0%
Branches: 41 54 75.9%

Line Branch Exec Source
1 /*
2 * copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * some optimization ideas from aes128.c by Reimar Doeffinger
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include <string.h>
24
25 #include "config.h"
26 #include "aes.h"
27 #include "aes_internal.h"
28 #include "error.h"
29 #include "intreadwrite.h"
30 #include "macros.h"
31 #include "mem.h"
32
33 const int av_aes_size= sizeof(AVAES);
34
35 16 struct AVAES *av_aes_alloc(void)
36 {
37 16 return av_mallocz(sizeof(struct AVAES));
38 }
39
40 static const uint8_t rcon[10] = {
41 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
42 };
43
44 static uint8_t sbox[256];
45 static uint8_t inv_sbox[256];
46 #if CONFIG_SMALL
47 static uint32_t enc_multbl[1][256];
48 static uint32_t dec_multbl[1][256];
49 #else
50 static uint32_t enc_multbl[4][256];
51 static uint32_t dec_multbl[4][256];
52 #endif
53
54 #if HAVE_BIGENDIAN
55 # define ROT(x, s) (((x) >> (s)) | ((x) << (32-(s))))
56 #else
57 # define ROT(x, s) (((x) << (s)) | ((x) >> (32-(s))))
58 #endif
59
60 47934 static inline void addkey(av_aes_block *dst, const av_aes_block *src,
61 const av_aes_block *round_key)
62 {
63 47934 dst->u64[0] = src->u64[0] ^ round_key->u64[0];
64 47934 dst->u64[1] = src->u64[1] ^ round_key->u64[1];
65 47934 }
66
67 5326 static inline void addkey_s(av_aes_block *dst, const uint8_t *src,
68 const av_aes_block *round_key)
69 {
70 5326 dst->u64[0] = AV_RN64(src) ^ round_key->u64[0];
71 5326 dst->u64[1] = AV_RN64(src + 8) ^ round_key->u64[1];
72 5326 }
73
74 5326 static inline void addkey_d(uint8_t *dst, const av_aes_block *src,
75 const av_aes_block *round_key)
76 {
77 5326 AV_WN64(dst, src->u64[0] ^ round_key->u64[0]);
78 5326 AV_WN64(dst + 8, src->u64[1] ^ round_key->u64[1]);
79 5326 }
80
81 5344 static void subshift(av_aes_block s0[2], int s, const uint8_t *box)
82 {
83 5344 unsigned char *s1_dst = (unsigned char*)s0[0].u8 + 3 - s;
84 5344 const unsigned char *s1_src = s1_dst + sizeof(*s0);
85 5344 unsigned char *s3_dst = (unsigned char*)s0[0].u8 + s + 1;
86 5344 const unsigned char *s3_src = s3_dst + sizeof(*s0);
87
88 5344 s0[0].u8[ 0] = box[s0[1].u8[ 0]];
89 5344 s0[0].u8[ 4] = box[s0[1].u8[ 4]];
90 5344 s0[0].u8[ 8] = box[s0[1].u8[ 8]];
91 5344 s0[0].u8[12] = box[s0[1].u8[12]];
92 5344 s1_dst[ 0] = box[s1_src[ 4]];
93 5344 s1_dst[ 4] = box[s1_src[ 8]];
94 5344 s1_dst[ 8] = box[s1_src[12]];
95 5344 s1_dst[12] = box[s1_src[ 0]];
96 5344 s0[0].u8[ 2] = box[s0[1].u8[10]];
97 5344 s0[0].u8[10] = box[s0[1].u8[ 2]];
98 5344 s0[0].u8[ 6] = box[s0[1].u8[14]];
99 5344 s0[0].u8[14] = box[s0[1].u8[ 6]];
100 5344 s3_dst[ 0] = box[s3_src[12]];
101 5344 s3_dst[12] = box[s3_src[ 8]];
102 5344 s3_dst[ 8] = box[s3_src[ 4]];
103 5344 s3_dst[ 4] = box[s3_src[ 0]];
104 5344 }
105
106 191808 static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d)
107 {
108 #if CONFIG_SMALL
109 return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
110 #else
111 191808 return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
112 #endif
113 }
114
115 47952 static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3)
116 {
117 47952 uint8_t (*src)[4] = state[1].u8x4;
118 47952 state[0].u32[0] = mix_core(multbl, src[0][0], src[s1 ][1], src[2][2], src[s3 ][3]);
119 47952 state[0].u32[1] = mix_core(multbl, src[1][0], src[s3 - 1][1], src[3][2], src[s1 - 1][3]);
120 47952 state[0].u32[2] = mix_core(multbl, src[2][0], src[s3 ][1], src[0][2], src[s1 ][3]);
121 47952 state[0].u32[3] = mix_core(multbl, src[3][0], src[s1 - 1][1], src[1][2], src[s3 - 1][3]);
122 47952 }
123
124 5326 static inline void aes_crypt(AVAES *a, int s, const uint8_t *sbox,
125 uint32_t multbl[][256])
126 {
127 int r;
128
129
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53260 for (r = a->rounds - 1; r > 0; r--) {
130 47934 mix(a->state, multbl, 3 - s, 1 + s);
131 47934 addkey(&a->state[1], &a->state[0], &a->round_key[r]);
132 }
133
134 5326 subshift(&a->state[0], s, sbox);
135 5326 }
136
137 5324 static void aes_encrypt(AVAES *a, uint8_t *dst, const uint8_t *src,
138 int count, uint8_t *iv, int rounds)
139 {
140
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10648 while (count--) {
141 5324 addkey_s(&a->state[1], src, &a->round_key[rounds]);
142
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5324 if (iv)
143 addkey_s(&a->state[1], iv, &a->state[1]);
144 5324 aes_crypt(a, 2, sbox, enc_multbl);
145 5324 addkey_d(dst, &a->state[0], &a->round_key[0]);
146
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5324 if (iv)
147 memcpy(iv, dst, 16);
148 5324 src += 16;
149 5324 dst += 16;
150 }
151 5324 }
152
153 2 static void aes_decrypt(AVAES *a, uint8_t *dst, const uint8_t *src,
154 int count, uint8_t *iv, int rounds)
155 {
156
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4 while (count--) {
157 2 addkey_s(&a->state[1], src, &a->round_key[rounds]);
158 2 aes_crypt(a, 0, inv_sbox, dec_multbl);
159
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2 if (iv) {
160 addkey_s(&a->state[0], iv, &a->state[0]);
161 memcpy(iv, src, 16);
162 }
163 2 addkey_d(dst, &a->state[0], &a->round_key[0]);
164 2 src += 16;
165 2 dst += 16;
166 }
167 2 }
168
169 5326 void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src,
170 int count, uint8_t *iv, int decrypt)
171 {
172 5326 a->crypt(a, dst, src, count, iv, a->rounds);
173 5326 }
174
175 12 static void init_multbl2(uint32_t tbl[][256], const int c[4],
176 const uint8_t *log8, const uint8_t *alog8,
177 const uint8_t *sbox)
178 {
179 int i;
180
181
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3084 for (i = 0; i < 256; i++) {
182 3072 int x = sbox[i];
183
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3072 if (x) {
184 int k, l, m, n;
185 3060 x = log8[x];
186 3060 k = alog8[x + log8[c[0]]];
187 3060 l = alog8[x + log8[c[1]]];
188 3060 m = alog8[x + log8[c[2]]];
189 3060 n = alog8[x + log8[c[3]]];
190 3060 tbl[0][i] = AV_NE(MKBETAG(k, l, m, n), MKTAG(k, l, m, n));
191 #if !CONFIG_SMALL
192 3060 tbl[1][i] = ROT(tbl[0][i], 8);
193 3060 tbl[2][i] = ROT(tbl[0][i], 16);
194 3060 tbl[3][i] = ROT(tbl[0][i], 24);
195 #endif
196 }
197 }
198 12 }
199
200 // this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
201 40 int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
202 {
203 40 int i, j, t, rconpointer = 0;
204 uint8_t tk[8][4];
205 40 int KC = key_bits >> 5;
206 40 int rounds = KC + 6;
207 uint8_t log8[256];
208 uint8_t alog8[512];
209
210
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40 a->crypt = decrypt ? aes_decrypt : aes_encrypt;
211
212
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40 if (!enc_multbl[FF_ARRAY_ELEMS(enc_multbl) - 1][FF_ARRAY_ELEMS(enc_multbl[0]) - 1]) {
213 6 j = 1;
214
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1536 for (i = 0; i < 255; i++) {
215 1530 alog8[i] = alog8[i + 255] = j;
216 1530 log8[j] = i;
217 1530 j ^= j + j;
218
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1530 if (j > 255)
219 768 j ^= 0x11B;
220 }
221
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1542 for (i = 0; i < 256; i++) {
222
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1536 j = i ? alog8[255 - log8[i]] : 0;
223 1536 j ^= (j << 1) ^ (j << 2) ^ (j << 3) ^ (j << 4);
224 1536 j = (j ^ (j >> 8) ^ 99) & 255;
225 1536 inv_sbox[j] = i;
226 1536 sbox[i] = j;
227 }
228 6 init_multbl2(dec_multbl, (const int[4]) { 0xe, 0x9, 0xd, 0xb },
229 log8, alog8, inv_sbox);
230 6 init_multbl2(enc_multbl, (const int[4]) { 0x2, 0x1, 0x1, 0x3 },
231 log8, alog8, sbox);
232 }
233
234
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40 if (key_bits != 128 && key_bits != 192 && key_bits != 256)
235 return AVERROR(EINVAL);
236
237 40 a->rounds = rounds;
238
239 40 memcpy(tk, key, KC * 4);
240 40 memcpy(a->round_key[0].u8, key, KC * 4);
241
242
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440 for (t = KC * 4; t < (rounds + 1) * 16; t += KC * 4) {
243
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2000 for (i = 0; i < 4; i++)
244 1600 tk[0][i] ^= sbox[tk[KC - 1][(i + 1) & 3]];
245 400 tk[0][0] ^= rcon[rconpointer++];
246
247
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1600 for (j = 1; j < KC; j++) {
248
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1200 if (KC != 8 || j != KC >> 1)
249
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6000 for (i = 0; i < 4; i++)
250 4800 tk[j][i] ^= tk[j - 1][i];
251 else
252 for (i = 0; i < 4; i++)
253 tk[j][i] ^= sbox[tk[j - 1][i]];
254 }
255
256 400 memcpy((unsigned char*)a->round_key + t, tk, KC * 4);
257 }
258
259
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40 if (decrypt) {
260
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20 for (i = 1; i < rounds; i++) {
261 av_aes_block tmp[3];
262 18 tmp[2] = a->round_key[i];
263 18 subshift(&tmp[1], 0, sbox);
264 18 mix(tmp, dec_multbl, 1, 3);
265 18 a->round_key[i] = tmp[0];
266 }
267 } else {
268
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228 for (i = 0; i < (rounds + 1) >> 1; i++)
269 190 FFSWAP(av_aes_block, a->round_key[i], a->round_key[rounds - i]);
270 }
271
272 40 return 0;
273 }
274
275