From 6dfda35dd29d2e2a86554d2c05d957a09ab79b0c Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 10 Jul 2019 23:27:19 +0200 Subject: [PATCH] avcodec/vc1_pred: Fix invalid shift in scaleforsame() Fixes: left shift of negative value -1 Fixes: 15531/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1IMAGE_fuzzer-5759556258365440 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/vc1_pred.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/vc1_pred.c b/libavcodec/vc1_pred.c index 9e29b44a1f..16565063ea 100644 --- a/libavcodec/vc1_pred.c +++ b/libavcodec/vc1_pred.c @@ -178,7 +178,7 @@ static av_always_inline int scaleforsame(VC1Context *v, int i, int n /* MV */, brfd = FFMIN(v->brfd, 3); scalesame = ff_vc1_b_field_mvpred_scales[0][brfd]; - n = (n * scalesame >> 8) << hpel; + n = (n * scalesame >> 8) * (1 << hpel); return n; }