[FFmpeg-devel] [PATCH 5/5] avcodec/hevc/ps: use unsigned shift

[Michael Niedermayer]

On Fri, Aug 16, 2024 at 08:27:07PM -0300, James Almer wrote:
> On 8/16/2024 8:15 PM, Michael Niedermayer wrote:
> > Fixes: left shift of 1 by 31 places cannot be represented in type 'int'
> > Fixes: 70726/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-6149928703819776
> > 
> > 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/hevc/ps.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/libavcodec/hevc/ps.c b/libavcodec/hevc/ps.c
> > index 80ac35a7dbf..cd5ece72b0a 100644
> > --- a/libavcodec/hevc/ps.c
> > +++ b/libavcodec/hevc/ps.c
> > @@ -1101,7 +1101,7 @@ int ff_hevc_parse_sps(HEVCSPS *sps, GetBitContext *gb, unsigned int *sps_id,
> >           sps->used_by_curr_pic_lt = 0;
> >           for (i = 0; i < sps->num_long_term_ref_pics_sps; i++) {
> >               sps->lt_ref_pic_poc_lsb_sps[i]       = get_bits(gb, sps->log2_max_poc_lsb);
> > -            sps->used_by_curr_pic_lt            |= get_bits1(gb) * (1 << i);
> > +            sps->used_by_curr_pic_lt            |= get_bits1(gb) * (1U << i);
> 
> Why not just get_bits1(gb) << i? get_bits1() returns an unsigned int (Either
> 0 or 1), so no chances for a left shift of negative number.

ok, will apply with that

thx

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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