From 570826b6323592fb1b78b1f790165b8cc4e2648b Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 12 Mar 2017 03:04:04 +0100 Subject: [PATCH] avcodec/mpeg12dec: Fix runtime error: left shift of negative value -1 Fixes: 764/clusterfuzz-testcase-6273034652483584 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit a720b854b0d3f0fae2b1eac644dd39e5821cacb1) Signed-off-by: Michael Niedermayer --- libavcodec/mpeg12dec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c index 62aaec1424..07efd6afa9 100644 --- a/libavcodec/mpeg12dec.c +++ b/libavcodec/mpeg12dec.c @@ -1046,7 +1046,7 @@ static int mpeg_decode_mb(MpegEncContext *s, int16_t block[12][64]) cbp = get_vlc2(&s->gb, ff_mb_pat_vlc.table, MB_PAT_VLC_BITS, 1); if (mb_block_count > 6) { - cbp <<= mb_block_count - 6; + cbp *= 1 << mb_block_count - 6; cbp |= get_bits(&s->gb, mb_block_count - 6); s->bdsp.clear_blocks(s->block[6]); }