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| author | Michael Niedermayer <michaelni@gmx.at> | 2012-09-30 17:46:37 +0200 |
|---|---|---|
| committer | Martin Storsjö <martin@martin.st> | 2012-10-03 19:19:49 +0300 |
| commit | b4345004319eee35e697520ca305eb95db0669e9 (patch) | |
| tree | 8d0934fe7557a9204e0391cd5ba5b58665c4049f /libavutil/xtea.c | |
| parent | ca074cc3134cb81c086f54b441f0bbde4d4249e7 (diff) | |
| download | ffmpeg-b4345004319eee35e697520ca305eb95db0669e9.tar.gz | |
xtea: Fix CBC decryption when src==dst
Signed-off-by: Martin Storsjö <martin@martin.st>
Diffstat (limited to 'libavutil/xtea.c')
| -rw-r--r-- | libavutil/xtea.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/libavutil/xtea.c b/libavutil/xtea.c index 11ae2664bb..cf63670dbe 100644 --- a/libavutil/xtea.c +++ b/libavutil/xtea.c @@ -36,7 +36,7 @@ void av_xtea_init(AVXTEA *ctx, const uint8_t key[16]) } static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, - int decrypt) + int decrypt, uint8_t *iv) { uint32_t v0, v1; int i; @@ -52,6 +52,11 @@ static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, sum -= delta; v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]); } + if (iv) { + v0 ^= AV_RB32(iv); + v1 ^= AV_RB32(iv + 4); + memcpy(iv, src, 8); + } } else { uint32_t sum = 0, delta = 0x9E3779B9; @@ -73,13 +78,7 @@ void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count, if (decrypt) { while (count--) { - xtea_crypt_ecb(ctx, dst, src, decrypt); - - if (iv) { - for (i = 0; i < 8; i++) - dst[i] = dst[i] ^ iv[i]; - memcpy(iv, src, 8); - } + xtea_crypt_ecb(ctx, dst, src, decrypt, iv); src += 8; dst += 8; @@ -89,10 +88,10 @@ void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count, if (iv) { for (i = 0; i < 8; i++) dst[i] = src[i] ^ iv[i]; - xtea_crypt_ecb(ctx, dst, dst, decrypt); + xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL); memcpy(iv, dst, 8); } else { - xtea_crypt_ecb(ctx, dst, src, decrypt); + xtea_crypt_ecb(ctx, dst, src, decrypt, NULL); } src += 8; dst += 8; |