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| author | Michael Niedermayer <michael@niedermayer.cc> | 2019-07-27 23:24:25 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2019-08-23 22:24:07 +0200 |
| commit | 4d4734bdc881de3af0ebe5935890a81423c80fdf (patch) | |
| tree | e6be2b2b119e571a8a9ca65eaed479761b55eb86 /libavcodec/lcldec.c | |
| parent | 965e766e4892cfc45c97cca88895248a7735e7d0 (diff) | |
| download | ffmpeg-4d4734bdc881de3af0ebe5935890a81423c80fdf.tar.gz | |
avcodec/lcldec: Check mthread_inlen instead of cliping
Clipping was added in 2009 to avoid crashes.
The clipped case would produce a 2nd slice with 0 input
thus also producing 0 output.
Subsequent checks will cause decoder failure unless both
slices have the same output length. thus the only way this
would not already fail is if the output from both slices
was 0 bytes.
Fixes: Timeout (134sec -> 241ms)
Fixes: 15599/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MSZH_fuzzer-5658127116009472
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Diffstat (limited to 'libavcodec/lcldec.c')
| -rw-r--r-- | libavcodec/lcldec.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/libavcodec/lcldec.c b/libavcodec/lcldec.c index 104defa5f5..046cdc4f8e 100644 --- a/libavcodec/lcldec.c +++ b/libavcodec/lcldec.c @@ -190,11 +190,10 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac ; } else if (c->flags & FLAG_MULTITHREAD) { mthread_inlen = AV_RL32(buf); - if (len < 8) { + if (len < 8 || len - 8 < mthread_inlen) { av_log(avctx, AV_LOG_ERROR, "len %d is too small\n", len); return AVERROR_INVALIDDATA; } - mthread_inlen = FFMIN(mthread_inlen, len - 8); mthread_outlen = AV_RL32(buf + 4); mthread_outlen = FFMIN(mthread_outlen, c->decomp_size); mszh_dlen = mszh_decomp(buf + 8, mthread_inlen, c->decomp_buf, c->decomp_size); |