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Avoid uninitialized data in lcldec when ofs is 0 in MSZH. 

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
(cherry picked from commit 42a1f1d7a8)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Reimar Döffinger 2011-12-30 10:42:55 +01:00 committed by Michael Niedermayer
parent 4ae111cf71
commit b8cc9e206b
2 changed files with 7 additions and 4 deletions
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8
libavcodec/lcldec.c
View File

@ -96,7 +96,13 @@ static unsigned int mszh_decomp(const unsigned char * srcptr, int srclen, unsign
ofs = FFMIN(ofs, destptr - destptr_bak); ofs = FFMIN(ofs, destptr - destptr_bak);
cnt *= 4; cnt *= 4;
cnt = FFMIN(cnt, destptr_end - destptr); cnt = FFMIN(cnt, destptr_end - destptr);
av_memcpy_backptr(destptr, ofs, cnt); if (ofs) {
av_memcpy_backptr(destptr, ofs, cnt);
} else {
// Not known what the correct behaviour is, but
// this at least avoids uninitialized data.
memset(destptr, 0, cnt);
}
destptr += cnt; destptr += cnt;
} }
maskbit >>= 1; maskbit >>= 1;

3
libavutil/lzo.h
View File

@ -67,9 +67,6 @@ int av_lzo1x_decode(void *out, int *outlen, const void *in, int *inlen);
* *
* cnt > back is valid, this will copy the bytes we just copied, * cnt > back is valid, this will copy the bytes we just copied,
* thus creating a repeating pattern with a period length of back. * thus creating a repeating pattern with a period length of back.
* Note that lcldec currently can set back == 0 - which is wrong and
* makes no sense, but the code should at least avoid crashing or hanging
* for this case.
*/ */
void av_memcpy_backptr(uint8_t *dst, int back, int cnt); void av_memcpy_backptr(uint8_t *dst, int back, int cnt);