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| author | Michael Niedermayer <michael@niedermayer.cc> | 2018-06-14 22:16:52 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2018-07-15 19:42:25 +0200 |
| commit | 8d21ab4d128ddae03fe6b21542c29dee240151db (patch) | |
| tree | bee04bb73a693a7f4597dae7247356c151a94339 | |
| parent | 7334985ffae8067b84884b5bd345db06fe2cc220 (diff) | |
| download | ffmpeg-8d21ab4d128ddae03fe6b21542c29dee240151db.tar.gz | |
avcodec/lagarith: Check that the range coded data stream is consistent when the probabilities indicate no data could have been coded.
Fixes: Timeout
Fixes: 8638/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_LAGARITH_fuzzer-5132046098759680
Fixes: 8943/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_LAGARITH_fuzzer-4883030219948032
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
| -rw-r--r-- | libavcodec/lagarith.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/libavcodec/lagarith.c b/libavcodec/lagarith.c index 0f4aa89486..ba2da2eeb2 100644 --- a/libavcodec/lagarith.c +++ b/libavcodec/lagarith.c @@ -141,6 +141,7 @@ static int lag_read_prob_header(lag_rac *rac, GetBitContext *gb) unsigned prob, cumulative_target; unsigned cumul_prob = 0; unsigned scaled_cumul_prob = 0; + int nnz = 0; rac->prob[0] = 0; rac->prob[257] = UINT_MAX; @@ -164,6 +165,8 @@ static int lag_read_prob_header(lag_rac *rac, GetBitContext *gb) prob = 256 - i; for (j = 0; j < prob; j++) rac->prob[++i] = 0; + }else { + nnz++; } } @@ -172,6 +175,10 @@ static int lag_read_prob_header(lag_rac *rac, GetBitContext *gb) return -1; } + if (nnz == 1 && (show_bits_long(gb, 32) & 0xFFFFFF)) { + return AVERROR_INVALIDDATA; + } + /* Scale probabilities so cumulative probability is an even power of 2. */ scale_factor = av_log2(cumul_prob); |