xfs: fix acl count validation in xfs_acl_from_disk()

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@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
[PG: in 2.6.34, xfs still had "linux-2.6" as a path component.]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/fs/xfs/linux-2.6/xfs_acl.c b/fs/xfs/linux-2.6/xfs_acl.c
index e82cce7b9ccfec3955ffacf81764838839dad16c..d509dfdd8cee420ce773ff8b68db26498bdfeff3 100644 (file)
--- a/fs/xfs/linux-2.6/xfs_acl.c
+++ b/fs/xfs/linux-2.6/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)