[FFmpeg-devel] [PATCH 2/3] avcodec/iff: Check length before memcpy() in decode_deep_rle32()

[Michael Niedermayer]

On Wed, Apr 22, 2020 at 08:10:44PM +1000, Peter Ross wrote:
> On Tue, Apr 21, 2020 at 12:03:40AM +0200, Michael Niedermayer wrote:
> > Fixes: out of array read
> > Fixes: 20796/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5111364702175232.fuzz
> > 
> > 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/iff.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/libavcodec/iff.c b/libavcodec/iff.c
> > index 2e65e266d0..23d19d8a25 100644
> > --- a/libavcodec/iff.c
> > +++ b/libavcodec/iff.c
> > @@ -722,6 +722,8 @@ static void decode_deep_rle32(uint8_t *dst, const uint8_t *src, int src_size, in
> >              int size = opcode + 1;
> >              for (i = 0; i < size; i++) {
> >                  int length = FFMIN(size - i, width);
> > +                if (src_end - src < length)
> > +                    return;
> >                  memcpy(dst + y*linesize + x * 4, src, length * 4);
> >                  src += length * 4;
> >                  x += length;
> 
> hi michael.
> 
> i think the guard should be:
> 
> if (src_end - src < length * 4)
>     return;

oops, will fix and apply

thx


[...]

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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

In fact, the RIAA has been known to suggest that students drop out
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