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| author | Michael Niedermayer <michael@niedermayer.cc> | 2019-10-19 21:27:41 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2019-11-24 22:58:59 +0100 |
| commit | 6014bcf1b74e903f535461ade4aa5fb44dbf5d8b (patch) | |
| tree | d6bdac953fea7fe50f2d5883f91984f2195aa3f1 /libavutil/lfg.h | |
| parent | 327a968817a366c24d1513526258a3dbbcf888a7 (diff) | |
| download | ffmpeg-6014bcf1b74e903f535461ade4aa5fb44dbf5d8b.tar.gz | |
avutil/lfg: Correct index increment type to avoid undefined behavior
Fixes: signed integer overflow: 2147483647 + 1 cannot be represented in type 'int'
Fixes: 18333/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_COMFORTNOISE_fuzzer-5668481831272448
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 'libavutil/lfg.h')
| -rw-r--r-- | libavutil/lfg.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/libavutil/lfg.h b/libavutil/lfg.h index ab38a8a0df..2b669205d1 100644 --- a/libavutil/lfg.h +++ b/libavutil/lfg.h @@ -51,8 +51,9 @@ int av_lfg_init_from_data(AVLFG *c, const uint8_t *data, unsigned int length); * it may be good enough and faster for your specific use case. */ static inline unsigned int av_lfg_get(AVLFG *c){ - c->state[c->index & 63] = c->state[(c->index-24) & 63] + c->state[(c->index-55) & 63]; - return c->state[c->index++ & 63]; + unsigned a = c->state[c->index & 63] = c->state[(c->index-24) & 63] + c->state[(c->index-55) & 63]; + c->index += 1U; + return a; } /** @@ -63,7 +64,9 @@ static inline unsigned int av_lfg_get(AVLFG *c){ static inline unsigned int av_mlfg_get(AVLFG *c){ unsigned int a= c->state[(c->index-55) & 63]; unsigned int b= c->state[(c->index-24) & 63]; - return c->state[c->index++ & 63] = 2*a*b+a+b; + a = c->state[c->index & 63] = 2*a*b+a+b; + c->index += 1U; + return a; } /** |