avcodec/vc1_block: Fix invalid left shift in vc1_decode_p_mb()
authorMichael Niedermayer <michael@niedermayer.cc>
Wed, 2 Oct 2019 17:53:44 +0000 (19:53 +0200)
committerMichael Niedermayer <michael@niedermayer.cc>
Thu, 3 Oct 2019 17:37:28 +0000 (19:37 +0200)
Fixes: left shift of negative value -6
Fixes: 17810/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1_fuzzer-5638541240958976

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
libavcodec/vc1_block.c

index fe7dbf8..f1c9f41 100644 (file)
@@ -1481,7 +1481,7 @@ static int vc1_decode_p_mb(VC1Context *v)
                     v->vc1dsp.vc1_inv_trans_8x8(v->block[v->cur_blk_idx][block_map[i]]);
                     if (v->rangeredfrm)
                         for (j = 0; j < 64; j++)
-                            v->block[v->cur_blk_idx][block_map[i]][j] <<= 1;
+                            v->block[v->cur_blk_idx][block_map[i]][j] *= 2;
                     block_cbp   |= 0xF << (i << 2);
                     block_intra |= 1 << i;
                 } else if (is_coded[i]) {