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Don't read past the AD buffer, even through an SIMD register

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This commit is contained in:
Frank Denis 2015-10-11 01:00:33 +02:00
parent 0b20d292df
commit 970058bb38
1 changed files with 9 additions and 13 deletions
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22
src/libsodium/crypto_aead/aes256gcm/aesni/aead_aes256gcm_aesni.c
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@ -203,21 +203,17 @@ static inline void
addmul(unsigned char *c, const unsigned char *a, unsigned int xlen, const unsigned char *b)
{
const __m128i rev = _mm_set_epi8(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);
const __m128i ff = _mm_set1_epi32(-1);
__m128i A = _mm_loadu_si128((const __m128i *) a);
__m128i A;
A = _mm_shuffle_epi8(A, rev);
if (xlen < 16) { /* less than 16 useful bytes - insert zeroes where needed */
uint64_t mask = -1ull ^ (1ull << (((16 - xlen) % 8) * 8)) - 1ull;
__m128i vm;
if (xlen > 8) {
vm = _mm_insert_epi64(ff, mask, 0);
} else {
vm = _mm_insert_epi64(_mm_setzero_si128(), mask, 1);
}
A = _mm_and_si128(vm, A);
if (xlen >= 16) {
A = _mm_loadu_si128((const __m128i *) a);
} else {
unsigned char padded[16];
memset(padded, 0, 16);
memcpy(padded, a, xlen);
A = _mm_loadu_si128((const __m128i *) padded);
}
A = _mm_shuffle_epi8(A, rev);
__m128i B = _mm_loadu_si128((const __m128i *) b);
__m128i C = _mm_loadu_si128((const __m128i *) c);
A = _mm_xor_si128(A, C);