avcodec/vc1_pred: Fix invalid shifts in scaleforopp()

Fixes: left shift of negative value -2
Fixes: 16964/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1IMAGE_fuzzer-5757853565976576

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 ced9a1cd0a)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-09-10 18:57:25 +02:00
parent 2e527ed7b1
commit 838b359225

View File

@ -191,9 +191,9 @@ static av_always_inline int scaleforopp(VC1Context *v, int n /* MV */,
n >>= hpel;
if (v->s.pict_type == AV_PICTURE_TYPE_B && !v->second_field && dir == 1) {
if (dim)
n = scaleforopp_y(v, n, dir) << hpel;
n = scaleforopp_y(v, n, dir) * (1 << hpel);
else
n = scaleforopp_x(v, n) << hpel;
n = scaleforopp_x(v, n) * (1 << hpel);
return n;
}
if (v->s.pict_type != AV_PICTURE_TYPE_B)