ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()

We get lower layer dentries, find their parents, do lock_rename() and
proceed to vfs_rename().  However, we do not check that dentries still
have the same parents and are not unlinked.  Need to check that...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 8 insertions, 3 deletions

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 49121e5a8de2..5c36ceecb5c1 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -593,11 +593,16 @@ ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
         lower_new_dir_dentry = dget_parent(lower_new_dentry);
         target_inode = d_inode(new_dentry);
         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+        rc = -EINVAL;
+        if (lower_old_dentry->d_parent != lower_old_dir_dentry)
+                goto out_lock;
+        if (lower_new_dentry->d_parent != lower_new_dir_dentry)
+                goto out_lock;
+        if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
+                goto out_lock;
         /* source should not be ancestor of target */
-        if (trap == lower_old_dentry) {
-                rc = -EINVAL;
+        if (trap == lower_old_dentry)
                 goto out_lock;
-        }
         /* target should not be ancestor of source */
         if (trap == lower_new_dentry) {
                 rc = -ENOTEMPTY;