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

Paul Gortmaker
2013-01-08T23:36:43Z

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

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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.
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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>
---
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