|author||Miklos Szeredi <email@example.com>||2016-05-11 01:16:37 +0200|
|committer||Al Viro <firstname.lastname@example.org>||2016-05-10 23:55:43 -0400|
vfs: rename: check backing inode being equal
If a file is renamed to a hardlink of itself POSIX specifies that rename(2) should do nothing and return success. This condition is checked in vfs_rename(). However it won't detect hard links on overlayfs where these are given separate inodes on the overlayfs layer. Overlayfs itself detects this condition and returns success without doing anything, but then vfs_rename() will proceed as if this was a successful rename (detach_mounts(), d_move()). The correct thing to do is to detect this condition before even calling into overlayfs. This patch does this by calling vfs_select_inode() to get the underlying inodes. Signed-off-by: Miklos Szeredi <email@example.com> Cc: <firstname.lastname@example.org> # v4.2+
1 files changed, 5 insertions, 1 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 1d9ca2d5dff6..3ef87d673bbe 100644
@@ -4213,7 +4213,11 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
bool new_is_dir = false;
unsigned max_links = new_dir->i_sb->s_max_links;
- if (source == target)
+ * Check source == target.
+ * On overlayfs need to look at underlying inodes.
+ if (vfs_select_inode(old_dentry, 0) == vfs_select_inode(new_dentry, 0))
error = may_delete(old_dir, old_dentry, is_dir);