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| author | Xi Wang <xi.wang@gmail.com> | 2013-03-15 06:59:22 -0400 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2014-06-23 18:17:42 +0200 |
| commit | 9ade5b804ea1ff98971972769c43497a597b0e77 (patch) | |
| tree | 2c7ef08ba925a7dcb520250e481398fa89583853 | |
| parent | 753f0738cae926be97c8b853f2bb5b325ceaa612 (diff) | |
| download | ffmpeg-9ade5b804ea1ff98971972769c43497a597b0e77.tar.gz | |
lzo: fix overflow checking in copy_backptr()
The check `src > dst' in the form `&c->out[-back] > c->out' invokes
pointer overflow, which is undefined behavior in C.
Remove the check. Also replace `&c->out[-back] < c->out_start' with
a safe form `c->out - c->out_start < back' to avoid overflow.
CC: libav-stable@libav.org
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
(cherry picked from commit ca6c3f2c53be70aa3c38e8f1292809db89ea1ba6)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
| -rw-r--r-- | libavutil/lzo.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/libavutil/lzo.c b/libavutil/lzo.c index c723257212..221a66b9ab 100644 --- a/libavutil/lzo.c +++ b/libavutil/lzo.c @@ -110,9 +110,8 @@ static inline void copy(LZOContext *c, int cnt) */ static inline void copy_backptr(LZOContext *c, int back, int cnt) { - register const uint8_t *src = &c->out[-back]; register uint8_t *dst = c->out; - if (src < c->out_start || src > dst) { + if (dst - c->out_start < back) { c->error |= AV_LZO_INVALID_BACKPTR; return; } |