[129/289] eCryptfs: Clear LOOKUP_OPEN flag when creating lower file

Greg KH
2010-12-08T01:36:16Z

From: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

commit 2e21b3f124eceb6ab5a07c8a061adce14ac94e14 upstream.

eCryptfs was passing the LOOKUP_OPEN flag through to the lower file
system, even though ecryptfs_create() doesn't support the flag. A valid
filp for the lower filesystem could be returned in the nameidata if the
lower file system's create() function supported LOOKUP_OPEN, possibly
resulting in unencrypted writes to the lower file.

However, this is only a potential problem in filesystems (FUSE, NFS,
CIFS, CEPH, 9p) that eCryptfs isn't known to support today.

https://bugs.launchpad.net/ecryptfs/+bug/641703

Reported-by: Kevin Buhr
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/ecryptfs/inode.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -70,15 +70,19 @@ ecryptfs_create_underlying_file(struct i
struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
struct dentry *dentry_save;
struct vfsmount *vfsmount_save;
+ unsigned int flags_save;
int rc;

dentry_save = nd->path.dentry;
vfsmount_save = nd->path.mnt;
+ flags_save = nd->flags;
nd->path.dentry = lower_dentry;
nd->path.mnt = lower_mnt;
+ nd->flags &= ~LOOKUP_OPEN;
rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
nd->path.dentry = dentry_save;
nd->path.mnt = vfsmount_save;
+ nd->flags = flags_save;
return rc;
}