From c40df2166c7925fc81e1ef22563c2e32124cf1d6 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 5 Dec 2019 22:35:03 +0100 Subject: [PATCH] avcodec/mpeg12dec: Fix invalid shift in mpeg2_fast_decode_block_intra() Fixes: left shift of negative value -695 Fixes: 19232/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG1VIDEO_fuzzer-5702856963522560 Fixes: 19555/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG1VIDEO_fuzzer-5741218147598336 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg 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 17f9495a1d..3927200e74 100644 --- a/libavcodec/mpeg12dec.c +++ b/libavcodec/mpeg12dec.c @@ -586,7 +586,7 @@ static inline int mpeg2_fast_decode_block_intra(MpegEncContext *s, dc = s->last_dc[component]; dc += diff; s->last_dc[component] = dc; - block[0] = dc << (3 - s->intra_dc_precision); + block[0] = dc * (1 << (3 - s->intra_dc_precision)); i = 0; if (s->intra_vlc_format) rl = &ff_rl_mpeg2;