From 317c63d3f42d1ae9e5c4146408026ca6b9c26fa3 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 2 Oct 2019 19:53:44 +0200 Subject: [PATCH] avcodec/vc1_block: Fix invalid left shift in vc1_decode_p_mb() Fixes: left shift of negative value -6 Fixes: 17810/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1_fuzzer-5638541240958976 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Reviewed-by: Paul B Mahol Signed-off-by: Michael Niedermayer (cherry picked from commit 2f588ccfb70cba54a7ea8e740110953da604c0e6) Signed-off-by: Michael Niedermayer --- libavcodec/vc1_block.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c index fe7dbf8b1d..f1c9f41f30 100644 --- a/libavcodec/vc1_block.c +++ b/libavcodec/vc1_block.c @@ -1481,7 +1481,7 @@ static int vc1_decode_p_mb(VC1Context *v) v->vc1dsp.vc1_inv_trans_8x8(v->block[v->cur_blk_idx][block_map[i]]); if (v->rangeredfrm) for (j = 0; j < 64; j++) - v->block[v->cur_blk_idx][block_map[i]][j] <<= 1; + v->block[v->cur_blk_idx][block_map[i]][j] *= 2; block_cbp |= 0xF << (i << 2); block_intra |= 1 << i; } else if (is_coded[i]) {