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avcodec/vc1_block: Fix invalid shifts in vc1_decode_i_blocks() 

Fixes: left shift of negative value -9
Fixes: 15299/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MSS2_fuzzer-5660922678345728
Fixes: 15557/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1IMAGE_fuzzer-5673351911047168

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-06-22 14:21:43 +02:00
parent b153ba1c2e
commit c9415e815a
1 changed files with 2 additions and 2 deletions
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4
libavcodec/vc1_block.c
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@ -2602,13 +2602,13 @@ static void vc1_decode_i_blocks(VC1Context *v)
if (v->rangeredfrm)
for (k = 0; k < 6; k++)
for (j = 0; j < 64; j++)
v->block[v->cur_blk_idx][block_map[k]][j] <<= 1;
v->block[v->cur_blk_idx][block_map[k]][j] *= 2;
vc1_put_blocks_clamped(v, 1);
} else {
if (v->rangeredfrm)
for (k = 0; k < 6; k++)
for (j = 0; j < 64; j++)
v->block[v->cur_blk_idx][block_map[k]][j] = (v->block[v->cur_blk_idx][block_map[k]][j] - 64) << 1;
v->block[v->cur_blk_idx][block_map[k]][j] = (v->block[v->cur_blk_idx][block_map[k]][j] - 64) * 2;
vc1_put_blocks_clamped(v, 0);
}