[FFmpeg-devel] [PATCH 3/3] avcodec/faxcompr: Check available bits in decode_uncompressed()

Michael Niedermayer michael at niedermayer.cc
Thu Jun 10 16:58:11 EEST 2021


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

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 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);
-- 
2.17.1



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