1. ffmpeg
  2. Commit d3b45f137882e16809295405ac2076a4872dc814
Browse code

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 <michael@niedermayer.cc>
(cherry picked from commit 413e0f2516eef678011cffd1ec6f0d92aa8bb96a)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

Michael Niedermayer authored on 2019/09/01 05:12:38
Showing 1 changed files
libavcodec/vc1_pred.c
History View file @ d3b45f1
... ... 
@@ -197,9 +197,10 @@ static av_always_inline int scaleforopp(VC1Context *v, int n /* MV */,
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         return n;
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     }
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     if (v->s.pict_type != AV_PICTURE_TYPE_B)
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-        refdist = FFMIN(v->refdist, 3);
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+        refdist = v->refdist;
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     else
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         refdist = dir ? v->brfd : v->frfd;
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+    refdist = FFMIN(refdist, 3);
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     scaleopp = ff_vc1_field_mvpred_scales[dir ^ v->second_field][0][refdist];
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     n = (n * scaleopp >> 8) * (1 << hpel);