[v2.6.34-stable 18/77] xfs: fix acl count validation in xfs_acl_from_disk()

[Paul Gortmaker]

From: Xi Wang <xi.wang@xxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

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>
[PG: in 2.6.34, xfs still had "linux-2.6" as a path component.]
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 fs/xfs/linux-2.6/xfs_acl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/linux-2.6/xfs_acl.c b/fs/xfs/linux-2.6/xfs_acl.c
index e82cce7..d509dfd 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)
-- 
1.7.12.1

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