| Message ID | 20200618122026.24534-3-michael@niedermayer.cc |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel,1/4] avcodec/mv30: Fix integer overflows in idct2_1d() | expand |
| Context | Check | Description |
|---|---|---|
| andriy/default | pending | |
| andriy/make | success | Make finished |
| andriy/make_fate | success | Make fate finished |
Michael Niedermayer: > Fixes: assertion failure > Fixes: left shift of 1 by 31 places cannot be represented in type 'int' > Fixes: 23264/clusterfuzz-testcase-minimized-ffmpeg_BSF_AV1_METADATA_fuzzer-6308429248593920 > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> > --- > libavcodec/cbs_av1.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/libavcodec/cbs_av1.c b/libavcodec/cbs_av1.c > index 29b316e011..4092c9dd06 100644 > --- a/libavcodec/cbs_av1.c > +++ b/libavcodec/cbs_av1.c > @@ -125,6 +125,8 @@ static int cbs_av1_write_uvlc(CodedBitstreamContext *ctx, PutBitContext *pbc, > put_bits(pbc, 1, 1); > } else { > zeroes = av_log2(value + 1); > + if (zeroes > 30) > + return AVERROR(EINVAL); > v = value - (1 << zeroes) + 1; > put_bits(pbc, zeroes + 1, 1); > put_bits(pbc, zeroes, v); > This will reject valid input. Instead one should just use unsigned; I've just sent a patch for this [1]. - Andreas [1]: https://ffmpeg.org/pipermail/ffmpeg-devel/2020-June/264725.html PS: Maybe one should an av_assert1(range_max < UINT32_MAX) to this function to ensure that value + 1 does not wraparound? (range_max equals UINT32_MAX - 1 for the only caller of this function (corresponding to the only occurence of this syntax element in the spec), so this is currently certainly true.)
diff --git a/libavcodec/cbs_av1.c b/libavcodec/cbs_av1.c index 29b316e011..4092c9dd06 100644 --- a/libavcodec/cbs_av1.c +++ b/libavcodec/cbs_av1.c @@ -125,6 +125,8 @@ static int cbs_av1_write_uvlc(CodedBitstreamContext *ctx, PutBitContext *pbc, put_bits(pbc, 1, 1); } else { zeroes = av_log2(value + 1); + if (zeroes > 30) + return AVERROR(EINVAL); v = value - (1 << zeroes) + 1; put_bits(pbc, zeroes + 1, 1); put_bits(pbc, zeroes, v);
Fixes: assertion failure Fixes: left shift of 1 by 31 places cannot be represented in type 'int' Fixes: 23264/clusterfuzz-testcase-minimized-ffmpeg_BSF_AV1_METADATA_fuzzer-6308429248593920 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavcodec/cbs_av1.c | 2 ++ 1 file changed, 2 insertions(+)