diff mbox series

[v6,28/40] overlayfs: do not mount on top of idmapped mounts

Message ID 20210121131959.646623-29-christian.brauner@ubuntu.com (mailing list archive)
State New
Headers show
Series idmapped mounts | expand

Commit Message

Christian Brauner Jan. 21, 2021, 1:19 p.m. UTC
Prevent overlayfs 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/20210112220124.837960-40-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
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
/* v2 */
patch introduced

/* v3 */
- Amir Goldstein <amir73il@gmail.com>:
  - Move check for idmapped lower layers into ovl_mount_dir_noesc().
- David Howells <dhowells@redhat.com>:
  - Adapt check after removing mnt_idmapped() helper.

/* v4 */
unchanged

/* v5 */
unchanged
base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837

/* v6 */
unchanged
base-commit: 19c329f6808995b142b3966301f217c831e7cf31
---
 fs/overlayfs/super.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

James Morris Jan. 22, 2021, 4:38 a.m. UTC | #1
On Thu, 21 Jan 2021, Christian Brauner wrote:

> Prevent overlayfs 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/20210112220124.837960-40-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
> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>


Reviewed-by: James Morris <jamorris@linux.microsoft.com>
diff mbox series

Patch

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index c04612b19054..b702c576e783 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -858,6 +858,10 @@  static int ovl_mount_dir_noesc(const char *name, struct path *path)
 		pr_err("filesystem on '%s' not supported\n", name);
 		goto out_put;
 	}
+	if (mnt_user_ns(path->mnt) != &init_user_ns) {
+		pr_err("idmapped layers are currently not supported\n");
+		goto out_put;
+	}
 	if (!d_is_dir(path->dentry)) {
 		pr_err("'%s' not a directory\n", name);
 		goto out_put;