[FFmpeg-devel] [PATCH 1/2] avcodec/hdrdec: Check for end of input in decompress()

[Michael Niedermayer]

On Mon, Dec 26, 2022 at 03:08:38PM +0100, Paul B Mahol wrote:
> On 12/25/22, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > Fixes: Timeout
> > Fixes:
> > 54386/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HDR_fuzzer-5053598268784640
> >
> > 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/hdrdec.c | 14 +++++++++++---
> >  1 file changed, 11 insertions(+), 3 deletions(-)
> >
> > diff --git a/libavcodec/hdrdec.c b/libavcodec/hdrdec.c
> > index 21d3e7f693..998227744b 100644
> > --- a/libavcodec/hdrdec.c
> > +++ b/libavcodec/hdrdec.c
> > @@ -58,6 +58,8 @@ static int decompress(uint8_t *scanline, int w,
> > GetByteContext *gb, const uint8_
> >      int rshift = 0;
> >
> >      while (w > 0) {
> > +        if (bytestream2_get_bytes_left(gb) < 4)
> > +            return AVERROR_INVALIDDATA;
> >          scanline[0] = bytestream2_get_byte(gb);
> >          scanline[1] = bytestream2_get_byte(gb);
> >          scanline[2] = bytestream2_get_byte(gb);
> > @@ -143,13 +145,17 @@ static int hdr_decode_frame(AVCodecContext *avctx,
> > AVFrame *p,
> >          int i;
> >
> >          if (width < MINELEN || width > MAXELEN) {
> > -            decompress(scanline, width, &gb, scanline);
> > +            ret = decompress(scanline, width, &gb, scanline);
> > +            if (ret < 0)
> > +                return ret;
> >              goto convert;
> >          }
> >
> >          i = bytestream2_peek_byte(&gb);
> >          if (i != 2) {
> > -            decompress(scanline, width, &gb, scanline);
> > +            ret = decompress(scanline, width, &gb, scanline);
> > +            if (ret < 0)
> > +                return ret;
> >              goto convert;
> >          }
> >          bytestream2_skip(&gb, 1);
> > @@ -161,7 +167,9 @@ static int hdr_decode_frame(AVCodecContext *avctx,
> > AVFrame *p,
> >          if (scanline[1] != 2 || scanline[2] & 128) {
> >              scanline[0] = 2;
> >              scanline[3] = i;
> > -            decompress(scanline + 4, width - 1, &gb, scanline);
> > +            ret = decompress(scanline + 4, width - 1, &gb, scanline);
> > +            if (ret < 0)
> > +                return ret;
> >              goto convert;
> >          }
> >
> > --
> > 2.17.1
> >
> 
> LGTM

will apply

thx

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

Good people do not need laws to tell them to act responsibly, while bad
people will find a way around the laws. -- Plato
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