avcodec/mpeg12dec: Fix runtime error: left shift of negative value -13
authorMichael Niedermayer <michael@niedermayer.cc>
Fri, 3 Mar 2017 03:39:05 +0000 (04:39 +0100)
committerMichael Niedermayer <michael@niedermayer.cc>
Sat, 4 Mar 2017 16:48:04 +0000 (17:48 +0100)
Fixes: 709/clusterfuzz-testcase-4789836449841152

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
libavcodec/mpeg12dec.c

index d44ddb2..27db14c 100644 (file)
@@ -497,7 +497,7 @@ static inline int mpeg2_decode_block_intra(MpegEncContext *s,
     dc  = s->last_dc[component];
     dc += diff;
     s->last_dc[component] = dc;
-    block[0] = dc << (3 - s->intra_dc_precision);
+    block[0] = dc * (1 << (3 - s->intra_dc_precision));
     ff_tlog(s->avctx, "dc=%d\n", block[0]);
     mismatch = block[0] ^ 1;
     i = 0;