[FFmpeg-devel] [PATCH 1/2] avcodec/wavpack: Check rate_x and sample rate for overflow

[Michael Niedermayer]

On Sun, May 03, 2020 at 04:13:47PM -0700, David Bryant wrote:
> On 5/2/20 2:08 PM, Michael Niedermayer wrote:
> > Fixes: shift exponent 32 is too large for 32-bit type 'int'
> > Fixes: 21647/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WAVPACK_fuzzer-5686168323883008
> >
> > 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/wavpack.c | 13 ++++++++++---
> >  1 file changed, 10 insertions(+), 3 deletions(-)
> >
> > diff --git a/libavcodec/wavpack.c b/libavcodec/wavpack.c
> > index 58ab561a15..ead57063c8 100644
> > --- a/libavcodec/wavpack.c
> > +++ b/libavcodec/wavpack.c
> > @@ -1359,7 +1359,10 @@ static int wavpack_decode_block(AVCodecContext *avctx, int block_no,
> >                  bytestream2_skip(&gb, ssize);
> >                  continue;
> >              }
> > -            rate_x = 1 << bytestream2_get_byte(&gb);
> > +            rate_x = bytestream2_get_byte(&gb);
> > +            if (rate_x > 30)
> > +                return AVERROR_INVALIDDATA;
> > +            rate_x = 1 << rate_x;
> >              dsd_mode = bytestream2_get_byte(&gb);
> >              if (dsd_mode && dsd_mode != 1 && dsd_mode != 3) {
> >                  av_log(avctx, AV_LOG_ERROR, "Invalid DSD encoding mode: %d\n",
> > @@ -1498,9 +1501,13 @@ static int wavpack_decode_block(AVCodecContext *avctx, int block_no,
> >                  av_log(avctx, AV_LOG_ERROR, "Custom sample rate missing.\n");
> >                  return AVERROR_INVALIDDATA;
> >              }
> > -            new_samplerate = sample_rate * rate_x;
> > +            new_samplerate = sample_rate;
> >          } else
> > -            new_samplerate = wv_rates[sr] * rate_x;
> > +            new_samplerate = wv_rates[sr];
> > +
> > +        if (new_samplerate * (uint64_t)rate_x > INT_MAX)
> > +            return AVERROR_INVALIDDATA;
> > +        new_samplerate *= rate_x;
> >  
> >          if (multiblock) {
> >              if (chan)
> 
> Looks correct to me. Thanks.

will apply

thx

[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Freedom in capitalist society always remains about the same as it was in
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