[PATCH 12/13] ovl: switch to __inode_permission()

Miklos Szeredi
2012-08-15T15:48:01Z

From: Andy Whitcroft <apw@canonical.com>

When checking permissions on an overlayfs inode we do not take into
account either device cgroup restrictions nor security permissions.
This allows a user to mount an overlayfs layer over a restricted device
directory and by pass those permissions to open otherwise restricted
files.

Switch over to __inode_permissions.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
fs/overlayfs/inode.c | 12 +-----------
1 files changed, 1 insertions(+), 11 deletions(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index e854720..f3a534f 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -100,19 +100,9 @@ int ovl_permission(struct inode *inode, int mask)
if (is_upper && !IS_RDONLY(inode) && IS_RDONLY(realinode) &&
(S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
goto out_dput;
-
- /*
- * Nobody gets write access to an immutable file.
- */
- err = -EACCES;
- if (IS_IMMUTABLE(realinode))
- goto out_dput;
}

- if (realinode->i_op->permission)
- err = realinode->i_op->permission(realinode, mask);
- else
- err = generic_permission(realinode, mask);
+ err = __inode_permission(realinode, mask);
out_dput:
dput(alias);
return err;
--
1.7.7