[maverick, maverick/ti-omap4, natty, natty/ti-omap4 CVE 2/2] xfs: fix acl count validation in xfs_acl_from_disk()

[Andy Whitcroft]

From: Xi Wang <xi.wang at gmail.com>

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 at gmail.com>
Reviewed-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Ben Myers <bpm at sgi.com>

(cherry-picked from commit 093019cf1b18dd31b2c3b77acce4e000e2cbc9ce)
CVE-2012-0038
BugLink: http://bugs.launchpad.net/bugs/917706
Signed-off-by: Andy Whitcroft <apw at canonical.com>
---
 fs/xfs/linux-2.6/xfs_acl.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_acl.c b/fs/xfs/linux-2.6/xfs_acl.c
index 46556ee..3423aba 100644
--- 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)
-- 
1.7.5.4