[FFmpeg-cvslog] avcodec/faxcompr: Check available bits in decode_uncompressed()

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Wed Jun  9 21:25:58 2021 +0200| [29d3e924a666c5837bd3cce48631da66e5ddbc50] | committer: Michael Niedermayer

avcodec/faxcompr: Check available bits in decode_uncompressed()

Fixes: Timeout
Fixes: 34950/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-5686764151898112
Fixes: 34966/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-4587409334468608

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit ff56c139e07a4de2803b974b6595f6b71fbf53bd)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=29d3e924a666c5837bd3cce48631da66e5ddbc50
---

 libavcodec/faxcompr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/faxcompr.c b/libavcodec/faxcompr.c
index 45e0c482d7..44c1f6f6b9 100644
--- a/libavcodec/faxcompr.c
+++ b/libavcodec/faxcompr.c
@@ -144,6 +144,8 @@ static int decode_uncompressed(AVCodecContext *avctx, GetBitContext *gb,
                 return AVERROR_INVALIDDATA;
             }
             cwi = 10 - av_log2(cwi);
+            if (get_bits_left(gb) < cwi + 1)
+                return AVERROR_INVALIDDATA;
             skip_bits(gb, cwi + 1);
             if (cwi > 5) {
                 newmode = get_bits1(gb);