xfs: validate acl count

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

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

diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index b6c4b3795c4a000ce27ac3799b5c39ae6c8044e9..76e4266d2e7e4a8fc3bfc609016e4de467b7e5cf 100644 (file)
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/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)