[FFmpeg-devel] [PATCH] avcodec/faxcompr: Check for end of bitstream in decode_group3_1d_line() and decode_group3_2d_line()

[Michael Niedermayer]

On Thu, Apr 29, 2021 at 05:25:40PM +0200, Andreas Rheinhardt wrote:
> Michael Niedermayer:
> > Fixes: infinite loop
> > Fixes: 33674/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-4816457818046464
> > 
> > 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/faxcompr.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/libavcodec/faxcompr.c b/libavcodec/faxcompr.c
> > index 7bf11d80ca..1fc4aca0b3 100644
> > --- a/libavcodec/faxcompr.c
> > +++ b/libavcodec/faxcompr.c
> > @@ -209,6 +209,8 @@ static int decode_group3_1d_line(AVCodecContext *avctx, GetBitContext *gb,
> >      unsigned int run = 0;
> >      unsigned int t;
> >      for (;;) {
> > +        if (get_bits_left(gb) <= 0)
> > +            return AVERROR_INVALIDDATA;
> >          t    = get_vlc2(gb, ccitt_vlc[mode].table, 9, 2);
> >          run += t;
> >          if (t < 64) {
> > @@ -254,6 +256,8 @@ static int decode_group3_2d_line(AVCodecContext *avctx, GetBitContext *gb,
> >      unsigned int offs = 0, run = 0;
> >  
> >      while (offs < width) {
> > +        if (get_bits_left(gb) <= 0)
> > +            return AVERROR_INVALIDDATA;
> 
> This will give the typical statement-before-declaration warning.

will commit without the warning

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire
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