[FFmpeg-devel] [PATCH 4/4] avcodec/vqcdec: Check for end of input in decode_vectors()
Michael Niedermayer
michael at niedermayer.cc
Sat Nov 19 22:04:45 EET 2022
On Sat, Nov 19, 2022 at 10:03:08AM +1100, Peter Ross wrote:
> On Fri, Nov 18, 2022 at 10:09:18PM +0100, Michael Niedermayer wrote:
> > Fixes: Timeout
> > Fixes: 52695/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VQC_fuzzer-4882310386548736
> >
> > 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/vqcdec.c | 14 ++++++++++----
> > 1 file changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/libavcodec/vqcdec.c b/libavcodec/vqcdec.c
> > index 5d1a03158c..18cd99462e 100644
> > --- a/libavcodec/vqcdec.c
> > +++ b/libavcodec/vqcdec.c
> > @@ -137,7 +137,7 @@ static void seed_codebooks(VqcContext * s, const int * seed)
> > }
> > }
> >
> > -static void decode_vectors(VqcContext * s, const uint8_t * buf, int size, int width, int height)
> > +static int decode_vectors(VqcContext * s, const uint8_t * buf, int size, int width, int height)
> > {
> > GetBitContext gb;
> > uint8_t * vectors = s->vectors;
> > @@ -155,9 +155,11 @@ static void decode_vectors(VqcContext * s, const uint8_t * buf, int size, int wi
> > *dst++ = get_bits(&gb, 8);
> >
> > while (show_bits(&gb, 2) != 2) {
> > -
> > if (dst >= vectors_end - 1)
> > - return;
> > + return 0;
> > +
> > + if (get_bits_left(&gb) < 4)
> > + return AVERROR_INVALIDDATA;
> >
> > if (!show_bits(&gb, 4)) {
> > *dst++ = 0;
> > @@ -182,6 +184,8 @@ static void decode_vectors(VqcContext * s, const uint8_t * buf, int size, int wi
> > skip_bits(&gb, 2);
> > vectors += 32;
> > }
> > +
> > + return 0;
> > }
> >
> > static void load_coeffs(VqcContext * s, const uint8_t * v, int width, int coeff_width)
> > @@ -392,7 +396,9 @@ static int vqc_decode_frame(AVCodecContext *avctx, AVFrame * rframe,
> > avpriv_request_sample(avctx, "gamma=0x%x, contrast=0x%x\n", gamma, contrast);
> >
> > seed_codebooks(s, seed);
> > - decode_vectors(s, buf + 7, avpkt->size - 7, avctx->width, avctx->height);
> > + ret = decode_vectors(s, buf + 7, avpkt->size - 7, avctx->width, avctx->height);
> > + if (ret < 0)
> > + return ret;
> > decode_frame(s, avctx->width, avctx->height);
>
> please apply
will apply
thx
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Avoid a single point of failure, be that a person or equipment.
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