[69/80] xfs: validate acl count

[Greg KH <gregkh@xxxxxxx>]

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

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

From: Christoph Hellwig <hch@xxxxxxxxxxxxx>

commit fa8b18edd752a8b4e9d1ee2cd615b82c93cf8bba upstream.

This prevents in-memory corruption and possible panics if the on-disk
ACL is badly corrupted.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Ben Myers <bpm@xxxxxxx>
Acked-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 fs/xfs/linux-2.6/xfs_acl.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/xfs/linux-2.6/xfs_acl.c
+++ b/fs/xfs/linux-2.6/xfs_acl.c
@@ -42,6 +42,8 @@ xfs_acl_from_disk(struct xfs_acl *aclp)
        int count, i;
 
        count = be32_to_cpu(aclp->acl_cnt);
+       if (count > XFS_ACL_MAX_ENTRIES)
+               return ERR_PTR(-EFSCORRUPTED);
 
        acl = posix_acl_alloc(count, GFP_KERNEL);
        if (!acl)