| Message ID | 20190808232350.16076-1-michael@niedermayer.cc |
|---|---|
| State | Accepted |
| Commit | 1fedba3c350a9eb22a1748c9056206d63d4d2dd9 |
| Headers | show |
LGTM On Fri, Aug 9, 2019 at 1:25 AM Michael Niedermayer <michael@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 <michael@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-request@ffmpeg.org with subject "unsubscribe".
On Sun, Aug 11, 2019 at 11:32:36AM +0200, Paul B Mahol wrote:
> LGTM
will apply
thx
[...]
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;
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: Michael Niedermayer <michael@niedermayer.cc> --- libavcodec/tiff.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)