Re: [FFmpeg-devel] [PATCH 4/4] avcodec/speedhq: Check width

[Michael Niedermayer <michael@niedermayer.cc>]

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On Sun, Aug 21, 2022 at 12:54:57PM +0200, Paul B Mahol wrote:
> On Fri, Aug 19, 2022 at 12:36 AM Michael Niedermayer <michael@niedermayer.cc>
> wrote:
> 
> > Fixes: out of array access
> > Fixes:
> > 50014/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SPEEDHQ_fuzzer-4748914632294400
> >
> > Alternatively the buffer size can be increased
> >
> > Found-by: continuous fuzzing process
> > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by
> > <https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by>:
> > Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >  libavcodec/speedhq.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/libavcodec/speedhq.c b/libavcodec/speedhq.c
> > index c43de4f199..ffee5f973b 100644
> > --- a/libavcodec/speedhq.c
> > +++ b/libavcodec/speedhq.c
> > @@ -499,7 +499,7 @@ static int speedhq_decode_frame(AVCodecContext *avctx,
> > AVFrame *frame,
> >      uint32_t second_field_offset;
> >      int ret;
> >
> > -    if (buf_size < 4 || avctx->width < 8)
> > +    if (buf_size < 4 || avctx->width < 8 || avctx->width % 8 != 0)
> >          return AVERROR_INVALIDDATA;
> >
> 
> Is this right thing to do?

We can increase the buffer size or change how the %8 != 0 case is handled
WIthout a non fuzzed file with such dimensions, I do not know what the
correct handling of such a file is.
What do you prefer to be done ?

Thanks

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If the United States is serious about tackling the national security threats 
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