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FFmpeg/libavutil/aes.c
Reimar Döffinger d086c1203c Add coverage exclusions for test code. 
For some of the code e.g. doing timing measurements there is no
real point in running regression testing on it, thus it should
not be counted against coverage.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
2011-12-05 20:05:44 +01:00

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/*
* copyright (c) 2007 Michael Niedermayer <michaelni@gmx.at>
*
* some optimization ideas from aes128.c by Reimar Doeffinger
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "common.h"
#include "aes.h"
#include "intreadwrite.h"
typedef union {
uint64_t u64[2];
uint32_t u32[4];
uint8_t u8x4[4][4];
uint8_t u8[16];
} av_aes_block;
typedef struct AVAES {
// Note: round_key[16] is accessed in the init code, but this only
// overwrites state, which does not matter (see also r7471).
av_aes_block round_key[15];
av_aes_block state[2];
int rounds;
} AVAES;
const int av_aes_size= sizeof(AVAES);
static const uint8_t rcon[10] = {
0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
};
static uint8_t sbox[256];
static uint8_t inv_sbox[256];
#if CONFIG_SMALL
static uint32_t enc_multbl[1][256];
static uint32_t dec_multbl[1][256];
#else
static uint32_t enc_multbl[4][256];
static uint32_t dec_multbl[4][256];
#endif
#if HAVE_BIGENDIAN
# define ROT(x, s) ((x >> s) | (x << (32-s)))
#else
# define ROT(x, s) ((x << s) | (x >> (32-s)))
#endif
static inline void addkey(av_aes_block *dst, const av_aes_block *src,
const av_aes_block *round_key)
{
dst->u64[0] = src->u64[0] ^ round_key->u64[0];
dst->u64[1] = src->u64[1] ^ round_key->u64[1];
}
static inline void addkey_s(av_aes_block *dst, const uint8_t *src,
const av_aes_block *round_key)
{
dst->u64[0] = AV_RN64(src) ^ round_key->u64[0];
dst->u64[1] = AV_RN64(src + 8) ^ round_key->u64[1];
}
static inline void addkey_d(uint8_t *dst, const av_aes_block *src,
const av_aes_block *round_key)
{
AV_WN64(dst, src->u64[0] ^ round_key->u64[0]);
AV_WN64(dst + 8, src->u64[1] ^ round_key->u64[1]);
}
static void subshift(av_aes_block s0[2], int s, const uint8_t *box)
{
av_aes_block *s1 = (av_aes_block *) (s0[0].u8 - s);
av_aes_block *s3 = (av_aes_block *) (s0[0].u8 + s);
s0[0].u8[ 0] = box[s0[1].u8[ 0]];
s0[0].u8[ 4] = box[s0[1].u8[ 4]];
s0[0].u8[ 8] = box[s0[1].u8[ 8]];
s0[0].u8[12] = box[s0[1].u8[12]];
s1[0].u8[ 3] = box[s1[1].u8[ 7]];
s1[0].u8[ 7] = box[s1[1].u8[11]];
s1[0].u8[11] = box[s1[1].u8[15]];
s1[0].u8[15] = box[s1[1].u8[ 3]];
s0[0].u8[ 2] = box[s0[1].u8[10]];
s0[0].u8[10] = box[s0[1].u8[ 2]];
s0[0].u8[ 6] = box[s0[1].u8[14]];
s0[0].u8[14] = box[s0[1].u8[ 6]];
s3[0].u8[ 1] = box[s3[1].u8[13]];
s3[0].u8[13] = box[s3[1].u8[ 9]];
s3[0].u8[ 9] = box[s3[1].u8[ 5]];
s3[0].u8[ 5] = box[s3[1].u8[ 1]];
}
static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d){
#if CONFIG_SMALL
return multbl[0][a] ^ ROT(multbl[0][b], 8) ^ ROT(multbl[0][c], 16) ^ ROT(multbl[0][d], 24);
#else
return multbl[0][a] ^ multbl[1][b] ^ multbl[2][c] ^ multbl[3][d];
#endif
}
static inline void mix(av_aes_block state[2], uint32_t multbl[][256], int s1, int s3){
uint8_t (*src)[4] = state[1].u8x4;
state[0].u32[0] = mix_core(multbl, src[0][0], src[s1 ][1], src[2][2], src[s3 ][3]);
state[0].u32[1] = mix_core(multbl, src[1][0], src[s3-1][1], src[3][2], src[s1-1][3]);
state[0].u32[2] = mix_core(multbl, src[2][0], src[s3 ][1], src[0][2], src[s1 ][3]);
state[0].u32[3] = mix_core(multbl, src[3][0], src[s1-1][1], src[1][2], src[s3-1][3]);
}
static inline void crypt(AVAES *a, int s, const uint8_t *sbox,
uint32_t multbl[][256])
{
int r;
for (r = a->rounds - 1; r > 0; r--) {
mix(a->state, multbl, 3 - s, 1 + s);
addkey(&a->state[1], &a->state[0], &a->round_key[r]);
}
subshift(&a->state[0], s, sbox);
}
void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src,
int count, uint8_t *iv, int decrypt)
{
while (count--) {
addkey_s(&a->state[1], src, &a->round_key[a->rounds]);
if (decrypt) {
crypt(a, 0, inv_sbox, dec_multbl);
if (iv) {
addkey_s(&a->state[0], iv, &a->state[0]);
memcpy(iv, src, 16);
}
addkey_d(dst, &a->state[0], &a->round_key[0]);
} else {
if (iv)
addkey_s(&a->state[1], iv, &a->state[1]);
crypt(a, 2, sbox, enc_multbl);
addkey_d(dst, &a->state[0], &a->round_key[0]);
if (iv)
memcpy(iv, dst, 16);
}
src += 16;
dst += 16;
}
}
static void init_multbl2(uint32_t tbl[][256], const int c[4],
const uint8_t *log8, const uint8_t *alog8,
const uint8_t *sbox)
{
int i;
for (i = 0; i < 256; i++) {
int x = sbox[i];
if (x) {
int k, l, m, n;
x = log8[x];
k = alog8[x + log8[c[0]]];
l = alog8[x + log8[c[1]]];
m = alog8[x + log8[c[2]]];
n = alog8[x + log8[c[3]]];
tbl[0][i] = AV_NE(MKBETAG(k,l,m,n), MKTAG(k,l,m,n));
#if !CONFIG_SMALL
tbl[1][i] = ROT(tbl[0][i], 8);
tbl[2][i] = ROT(tbl[0][i], 16);
tbl[3][i] = ROT(tbl[0][i], 24);
#endif
}
}
}
// this is based on the reference AES code by Paulo Barreto and Vincent Rijmen
int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
{
int i, j, t, rconpointer = 0;
uint8_t tk[8][4];
int KC = key_bits >> 5;
int rounds = KC + 6;
uint8_t log8[256];
uint8_t alog8[512];
if (!enc_multbl[FF_ARRAY_ELEMS(enc_multbl)-1][FF_ARRAY_ELEMS(enc_multbl[0])-1]) {
j = 1;
for (i = 0; i < 255; i++) {
alog8[i] = alog8[i + 255] = j;
log8[j] = i;
j ^= j + j;
if (j > 255)
j ^= 0x11B;
}
for (i = 0; i < 256; i++) {
j = i ? alog8[255 - log8[i]] : 0;
j ^= (j << 1) ^ (j << 2) ^ (j << 3) ^ (j << 4);
j = (j ^ (j >> 8) ^ 99) & 255;
inv_sbox[j] = i;
sbox[i] = j;
}
init_multbl2(dec_multbl, (const int[4]) { 0xe, 0x9, 0xd, 0xb },
log8, alog8, inv_sbox);
init_multbl2(enc_multbl, (const int[4]) { 0x2, 0x1, 0x1, 0x3 },
log8, alog8, sbox);
}
if (key_bits != 128 && key_bits != 192 && key_bits != 256)
return -1;
a->rounds = rounds;
memcpy(tk, key, KC * 4);
memcpy(a->round_key[0].u8, key, KC * 4);
for (t = KC * 4; t < (rounds + 1) * 16; t += KC * 4) {
for (i = 0; i < 4; i++)
tk[0][i] ^= sbox[tk[KC - 1][(i + 1) & 3]];
tk[0][0] ^= rcon[rconpointer++];
for (j = 1; j < KC; j++) {
if (KC != 8 || j != KC >> 1)
for (i = 0; i < 4; i++)
tk[j][i] ^= tk[j - 1][i];
else
for (i = 0; i < 4; i++)
tk[j][i] ^= sbox[tk[j - 1][i]];
}
memcpy(a->round_key[0].u8 + t, tk, KC * 4);
}
if (decrypt) {
for (i = 1; i < rounds; i++) {
av_aes_block tmp[3];
tmp[2] = a->round_key[i];
subshift(&tmp[1], 0, sbox);
mix(tmp, dec_multbl, 1, 3);
a->round_key[i] = tmp[0];
}
} else {
for (i = 0; i < (rounds + 1) >> 1; i++) {
FFSWAP(av_aes_block, a->round_key[i], a->round_key[rounds-i]);
}
}
return 0;
}
#ifdef TEST
// LCOV_EXCL_START
#include <string.h>
#include "lfg.h"
#include "log.h"
int main(int argc, char **argv)
{
int i, j;
AVAES b;
uint8_t rkey[2][16] = {
{ 0 },
{ 0x10, 0xa5, 0x88, 0x69, 0xd7, 0x4b, 0xe5, 0xa3,
0x74, 0xcf, 0x86, 0x7c, 0xfb, 0x47, 0x38, 0x59 }
};
uint8_t pt[16], rpt[2][16]= {
{ 0x6a, 0x84, 0x86, 0x7c, 0xd7, 0x7e, 0x12, 0xad,
0x07, 0xea, 0x1b, 0xe8, 0x95, 0xc5, 0x3f, 0xa3 },
{ 0 }
};
uint8_t rct[2][16]= {
{ 0x73, 0x22, 0x81, 0xc0, 0xa0, 0xaa, 0xb8, 0xf7,
0xa5, 0x4a, 0x0c, 0x67, 0xa0, 0xc4, 0x5e, 0xcf },
{ 0x6d, 0x25, 0x1e, 0x69, 0x44, 0xb0, 0x51, 0xe0,
0x4e, 0xaa, 0x6f, 0xb4, 0xdb, 0xf7, 0x84, 0x65 }
};
uint8_t temp[16];
int err = 0;
av_log_set_level(AV_LOG_DEBUG);
for (i = 0; i < 2; i++) {
av_aes_init(&b, rkey[i], 128, 1);
av_aes_crypt(&b, temp, rct[i], 1, NULL, 1);
for (j = 0; j < 16; j++) {
if (rpt[i][j] != temp[j]) {
av_log(NULL, AV_LOG_ERROR, "%d %02X %02X\n",
j, rpt[i][j], temp[j]);
err = 1;
}
}
}
if (argc > 1 && !strcmp(argv[1], "-t")) {
AVAES ae, ad;
AVLFG prng;
av_aes_init(&ae, "PI=3.141592654..", 128, 0);
av_aes_init(&ad, "PI=3.141592654..", 128, 1);
av_lfg_init(&prng, 1);
for (i = 0; i < 10000; i++) {
for (j = 0; j < 16; j++) {
pt[j] = av_lfg_get(&prng);
}
{
START_TIMER;
av_aes_crypt(&ae, temp, pt, 1, NULL, 0);
if (!(i & (i - 1)))
av_log(NULL, AV_LOG_ERROR, "%02X %02X %02X %02X\n",
temp[0], temp[5], temp[10], temp[15]);
av_aes_crypt(&ad, temp, temp, 1, NULL, 1);
STOP_TIMER("aes");
}
for (j = 0; j < 16; j++) {
if (pt[j] != temp[j]) {
av_log(NULL, AV_LOG_ERROR, "%d %d %02X %02X\n",
i, j, pt[j], temp[j]);
}
}
}
}
return err;
}
// LCOV_EXCL_STOP
#endif
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