On Fri, Oct 09, 2020 at 06:52:18PM +0200, Michael Niedermayer wrote: > On Thu, Oct 08, 2020 at 09:48:41PM +0200, Andreas Rheinhardt wrote: > > Michael Niedermayer: > > > Fixes: shift exponent -1 is negative > > > Fixes: > > > 26107/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PGX_fuzzer-5378790047612928 > > > > > > Found-by: continuous fuzzing process > > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > > --- > > > libavcodec/pgxdec.c | 6 +++--- > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/libavcodec/pgxdec.c b/libavcodec/pgxdec.c > > > index 150f8bbf66..5c735894ab 100644 > > > --- a/libavcodec/pgxdec.c > > > +++ b/libavcodec/pgxdec.c > > > @@ -133,14 +133,14 @@ static int pgx_decode_frame(AVCodecContext *avctx, > > > void *data, > > > if ((ret = ff_set_dimensions(avctx, width, height)) < 0) > > > return ret; > > > > > > - if (depth <= 8) { > > > + if (depth > 0 && depth <= 8) { > > > avctx->pix_fmt = AV_PIX_FMT_GRAY8; > > > bpp = 8; > > > - } else if (depth <= 16) { > > > + } else if (depth > 0 && depth <= 16) { > > > avctx->pix_fmt = AV_PIX_FMT_GRAY16; > > > bpp = 16; > > > } else { > > > - av_log(avctx, AV_LOG_ERROR, "Maximum depth of 16 bits > > > supported.\n"); > > > + av_log(avctx, AV_LOG_ERROR, "depth %d is invalid or > > > unsupported.\n", depth); > > > return AVERROR_PATCHWELCOME; > > > } > > > if (bytestream2_get_bytes_left(&g) < width * height * (bpp >> 3)) > > > > > I presume the parsed depth to be zero in your testcase. Said number > > comes from pgx_get_number() which is only used to parse values for which > > a value of zero makes no sense. Wouldn't it make more sense to error out > > there if the number is zero? > > I was considering that too when i wrote the patch > the reason why i picked this is thats where depth is checked already. > Checking for depth == 0 in one function and depth > 16 in another feels > like its not the clearest way to implement that ...
ok if i apply this ? or you still want it changed ? [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The bravest are surely those who have the clearest vision of what is before them, glory and danger alike, and yet notwithstanding go out to meet it. -- Thucydides
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