[FFmpeg-devel] [PATCH 3/5] avcodec/get_bits: Use FF_PTR_ADD() in init_get_bits()

[Michael Niedermayer]

On Thu, Jul 03, 2025 at 08:26:23AM +0100, Kieran Kunhya via ffmpeg-devel wrote:
> Date: Thu, 3 Jul 2025 08:26:23 +0100
> From: Kieran Kunhya <kieran618 at googlemail.com>
> To: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH 3/5] avcodec/get_bits: Use FF_PTR_ADD() in init_get_bits()
> 
> On Thu, 3 Jul 2025, 03:02 Michael Niedermayer, <michael at niedermayer.cc>
> wrote:
> 
> > Fixes: NULL + 0
> > Fixes:
> > 421817631/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APV_fuzzer-4957386534354944
> >
> > 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 at niedermayer.cc>
> > ---
> >  libavcodec/get_bits.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/libavcodec/get_bits.h b/libavcodec/get_bits.h
> > index 19542965697..bf6929aa65d 100644
> > --- a/libavcodec/get_bits.h
> > +++ b/libavcodec/get_bits.h
> > @@ -511,7 +511,7 @@ static inline int init_get_bits(GetBitContext *s,
> > const uint8_t *buffer,
> >      s->buffer             = buffer;
> >      s->size_in_bits       = bit_size;
> >      s->size_in_bits_plus8 = bit_size + 8;
> > -    s->buffer_end         = buffer + buffer_size;
> > +    s->buffer_end         = buffer_size ? buffer + buffer_size : buffer;
> >      s->index              = 0;
> >
> >      return ret;
> > --
> > 2.49.0
> >
> 
> Doesn't match commit message

yes, i didnt like either variant FF_PTR_ADD() needs #include internal.h
which thenb gets included in most of the codebase

ill post a better patch that avoids the bad arguments before init_get_bits*
is called

thx


[...]

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