From c01055a1ffe11390adf23ffa30516408cfcc5c3d Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 31 Aug 2019 22:12:38 +0200 Subject: [PATCH] avcodec/vc1_pred: Fix refdist in scaleforopp() Fixes: out of array access Fixes: 16601/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1IMAGE_fuzzer-5656105392275456 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 413e0f2516eef678011cffd1ec6f0d92aa8bb96a) Signed-off-by: Michael Niedermayer --- libavcodec/vc1_pred.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/libavcodec/vc1_pred.c b/libavcodec/vc1_pred.c index d45e719509..8763707ef8 100644 --- a/libavcodec/vc1_pred.c +++ b/libavcodec/vc1_pred.c @@ -197,9 +197,10 @@ static av_always_inline int scaleforopp(VC1Context *v, int n /* MV */, return n; } if (v->s.pict_type != AV_PICTURE_TYPE_B) - refdist = FFMIN(v->refdist, 3); + refdist = v->refdist; else refdist = dir ? v->brfd : v->frfd; + refdist = FFMIN(refdist, 3); scaleopp = ff_vc1_field_mvpred_scales[dir ^ v->second_field][0][refdist]; n = (n * scaleopp >> 8) * (1 << hpel);