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aes: fix invalid array indexing in init code 

This makes the code work with clang/x86_32 and removes several warnings.

Signed-off-by: Mans Rullgard <mans@mansr.com>
This commit is contained in:
Mans Rullgard 2011-07-02 22:10:25 +01:00
parent 21accb3bb2
commit 5d20f19be2
1 changed files with 21 additions and 13 deletions
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34
libavutil/aes.c
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@ -54,6 +54,8 @@ static uint32_t enc_multbl[4][256];
static uint32_t dec_multbl[4][256];
#endif
#define ROT(x, s) ((x << s) | (x >> (32-s)))
static inline void addkey(av_aes_block *dst, const av_aes_block *src,
const av_aes_block *round_key)
{
@ -86,7 +88,6 @@ static void subshift(av_aes_block s0[2], int s, const uint8_t *box)
static inline int mix_core(uint32_t multbl[][256], int a, int b, int c, int d){
#if CONFIG_SMALL
#define ROT(x,s) ((x<<s)|(x>>(32-s)))
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];
@ -143,22 +144,29 @@ void av_aes_crypt(AVAES *a, uint8_t *dst_, const uint8_t *src_,
}
}
static void init_multbl2(uint8_t tbl[1024], const int c[4],
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, j;
int i;
for (i = 0; i < 1024; i++) {
int x = sbox[i >> 2];
if (x)
tbl[i] = alog8[log8[x] + log8[c[i & 3]]];
}
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
for (j = 256; j < 1024; j++)
for (i = 0; i < 4; i++)
tbl[4*j + i] = tbl[4*j + ((i - 1) & 3) - 1024];
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
@ -187,9 +195,9 @@ int av_aes_init(AVAES *a, const uint8_t *key, int key_bits, int decrypt)
inv_sbox[j] = i;
sbox[i] = j;
}
init_multbl2(dec_multbl[0], (const int[4]) { 0xe, 0x9, 0xd, 0xb },
init_multbl2(dec_multbl, (const int[4]) { 0xe, 0x9, 0xd, 0xb },
log8, alog8, inv_sbox);
init_multbl2(enc_multbl[0], (const int[4]) { 0x2, 0x1, 0x1, 0x3 },
init_multbl2(enc_multbl, (const int[4]) { 0x2, 0x1, 0x1, 0x3 },
log8, alog8, sbox);
}