LGTM On Fri, Aug 9, 2019 at 1:25 AM Michael Niedermayer <mich...@niedermayer.cc> wrote:
> This may break some valid tiff files, it appears the specification does > not require > the offsets to be increasing. They increase in the 2 test files i have > though except > the last offset which is 0 (an end marker) and for which a special case is > added to > avoid asking for a sample for that end marker. > > See: [FFmpeg-devel] [PATCH 2/2] avcodec/tiff: Detect infinite retry loop > for an alternative implementation > > Fixes: Timeout (Infinite -> Finite) > Fixes: > 15706/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-5114674904825856 > > This variant was requested by paul on IRC > Found-by: continuous fuzzing process > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > Signed-off-by > <https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by>: > Michael Niedermayer <mich...@niedermayer.cc> > --- > libavcodec/tiff.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c > index c520d7df83..1f1a1a3698 100644 > --- a/libavcodec/tiff.c > +++ b/libavcodec/tiff.c > @@ -1399,7 +1399,7 @@ static int decode_frame(AVCodecContext *avctx, > TiffContext *const s = avctx->priv_data; > AVFrame *const p = data; > ThreadFrame frame = { .f = data }; > - unsigned off; > + unsigned off, last_off; > int le, ret, plane, planes; > int i, j, entries, stride; > unsigned soff, ssize; > @@ -1454,6 +1454,7 @@ again: > /** whether we should process this multi-page IFD's next page */ > retry_for_page = s->get_page && s->cur_page + 1 < s->get_page; // > get_page is 1-indexed > > + last_off = off; > if (retry_for_page) { > // set offset to the next IFD > off = ff_tget_long(&s->gb, le); > @@ -1463,6 +1464,14 @@ again: > } > > if (retry_for_subifd || retry_for_page) { > + if (!off) { > + av_log(avctx, AV_LOG_ERROR, "Requested entry not found\n"); > + return AVERROR_INVALIDDATA; > + } > + if (off <= last_off) { > + avpriv_request_sample(s->avctx, "non increasing IFD > offset\n"); > + return AVERROR_INVALIDDATA; > + } > if (off >= UINT_MAX - 14 || avpkt->size < off + 14) { > av_log(avctx, AV_LOG_ERROR, "IFD offset is greater than image > size\n"); > return AVERROR_INVALIDDATA; > -- > 2.22.0 > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
