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| author | Michael Niedermayer <michael@niedermayer.cc> | 2019-08-09 01:23:46 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2019-08-11 19:13:21 +0200 |
| commit | 1fedba3c350a9eb22a1748c9056206d63d4d2dd9 (patch) | |
| tree | 72c32d015e41ccf7bcad6280e1fc1246dfe07bda /libavcodec/tiff.c | |
| parent | 9cd1e939cf26e7a53f28cbbda22d27535981b9db (diff) | |
| download | ffmpeg-1fedba3c350a9eb22a1748c9056206d63d4d2dd9.tar.gz | |
avcodec/tiff: Enforce increasing offsets
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
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Diffstat (limited to 'libavcodec/tiff.c')
| -rw-r--r-- | libavcodec/tiff.c | 11 |
1 files changed, 10 insertions, 1 deletions
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; |