[49/49] xfs: fix acl count validation in xfs_acl_from_disk()

From: Greg KH
Date: Tue Jan 10 2012 - 18:06:49 EST


3.2-stable review patch. If anyone has any objections, please let me know.

------------------

From: Xi Wang <xi.wang@xxxxxxxxx>

commit 093019cf1b18dd31b2c3b77acce4e000e2cbc9ce upstream.

Commit fa8b18ed didn't prevent the integer overflow and possible
memory corruption. "count" can go negative and bypass the check.

Signed-off-by: Xi Wang <xi.wang@xxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Ben Myers <bpm@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
fs/xfs/xfs_acl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -39,7 +39,7 @@ xfs_acl_from_disk(struct xfs_acl *aclp)
struct posix_acl_entry *acl_e;
struct posix_acl *acl;
struct xfs_acl_entry *ace;
- int count, i;
+ unsigned int count, i;

count = be32_to_cpu(aclp->acl_cnt);
if (count > XFS_ACL_MAX_ENTRIES)


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