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| author | Michael Niedermayer <michael@niedermayer.cc> | 2019-10-19 21:27:41 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2019-12-31 19:51:56 +0100 |
| commit | f0bd54aaa78c9b965c9d135757adfc033bbf54be (patch) | |
| tree | f04b8a2f303c1dcab2e7b07d5db48fb7c299f603 | |
| parent | 3a6ef1926349c2b810c353956135a481309fa6f7 (diff) | |
| download | ffmpeg-f0bd54aaa78c9b965c9d135757adfc033bbf54be.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>
(cherry picked from commit 6014bcf1b74e903f535461ade4aa5fb44dbf5d8b)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
| -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; } /** |