[FFmpeg-devel] [PATCH 3/4] avcodec/dxv: Check op_offset in both directions

[Paul B Mahol]

On 7/19/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
> On Thu, Jun 27, 2019 at 09:32:44AM +0200, Paul B Mahol wrote:
>> On 6/27/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
>> > Fixes: signed integer overflow: 61 + 2147483647 cannot be represented
>> > in
>> > type 'int'
>> > Fixes:
>> > 15311/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DXV_fuzzer-5742552826773504
>> >
>> > Found-by: continuous fuzzing process
>> > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
>> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
>> > ---
>> >  libavcodec/dxv.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/libavcodec/dxv.c b/libavcodec/dxv.c
>> > index 5fd1844094..3506775560 100644
>> > --- a/libavcodec/dxv.c
>> > +++ b/libavcodec/dxv.c
>> > @@ -745,7 +745,7 @@ static int dxv_decompress_cocg(DXVContext *ctx,
>> > GetByteContext *gb,
>> >      int skip0, skip1, oi0 = 0, oi1 = 0;
>> >      int ret, state0 = 0, state1 = 0;
>> >
>> > -    if (op_offset < 12)
>> > +    if (op_offset < 12 || op_offset - 12 >
>> > bytestream2_get_bytes_left(gb))
>> >          return AVERROR_INVALIDDATA;
>> >
>> >      dst = tex_data;
>> > --
>> > 2.22.0
>> >
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>> >
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>>
>> Make sure this does not break any files.
>
> Do you have any specific files i should test ?
>
> I of course cannot test every file on earth ...

I'm on vacation, so when I get back I will give you some files.

>
> Thanks
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> If you fake or manipulate statistics in a paper in physics you will never
> get a job again.
> If you fake or manipulate statistics in a paper in medicin you will get
> a job for life at the pharma industry.
>