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Subject[PATCH] SquashFS, zlib: Don't use uninitialized variable in zlib_uncompress
In fs/squashfs/zlib_wrapper.c::zlib_uncompress() we have this code:

int zlib_err, zlib_init = 0;
...
do {
if (stream->avail_in == 0 && k < b) {
... [no code that assigns to 'zlib_err'] ...
if (avail == 0) {
offset = 0;
put_bh(bh[k++]);
continue;
}
...
} while (zlib_err == Z_OK);

If we hit that 'continue' statement the first time through, then the
'while' condition will be testing an uninitialized 'zlib_err' - not what
we want.

This patch should take care of the problem by making sure that 'zlib_err'
is initialized to 'Z_OK' at the start of the function.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
---
zlib_wrapper.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Compile tested only.

diff --git a/fs/squashfs/zlib_wrapper.c b/fs/squashfs/zlib_wrapper.c
index 818a5e0..5970993 100644
--- a/fs/squashfs/zlib_wrapper.c
+++ b/fs/squashfs/zlib_wrapper.c
@@ -65,7 +65,7 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
struct buffer_head **bh, int b, int offset, int length, int srclength,
int pages)
{
- int zlib_err, zlib_init = 0;
+ int zlib_err = Z_OK, zlib_init = 0;
int k = 0, page = 0;
z_stream *stream = msblk->stream;

--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please.



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