Unverified Commit 0f16ff0f authored Jan 21, 2021 by Christian Brauner

ecryptfs: do not mount on top of idmapped mounts

Prevent ecryptfs from being mounted on top of idmapped mounts.
Stacking filesystems need to be prevented from being mounted on top of
idmapped mounts until they have have been converted to handle this.

Link: https://lore.kernel.org/r/20210121131959.646623-28-christian.brauner@ubuntu.com

Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

parent a2d2329e

fs/ecryptfs/main.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -531,6 +531,12 @@ static struct dentry ecryptfs_mount(struct file_system_type fs_type, int flags
		goto out_free;
		}

		if (mnt_user_ns(path.mnt) != &init_user_ns) {
		rc = -EINVAL;
		printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
		goto out_free;
		}

		if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
		rc = -EPERM;
		printk(KERN_ERR "Mount of device (uid: %d) not owned by "