2021-01-21 15:04:13

by Christian Brauner

Subject: [PATCH v6 27/40] 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/[email protected]
Cc: Christoph Hellwig <[email protected]>
Cc: David Howells <[email protected]>
Cc: Al Viro <[email protected]>
Cc: [email protected]
Signed-off-by: Christian Brauner <[email protected]>
---
/* v2 */
patch introduced

/* v3 */
- David Howells <[email protected]>:
- Adapt check after removing mnt_idmapped() helper.

/* v4 */
unchanged

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

/* v6 */
unchanged
base-commit: 19c329f6808995b142b3966301f217c831e7cf31
---
fs/ecryptfs/main.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index e63259fdef28..cdf40a54a35d 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -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 "
--
2.30.0

2021-01-22 05:14:00

by James Morris

Subject: Re: [PATCH v6 27/40] ecryptfs: do not mount on top of idmapped mounts

On Thu, 21 Jan 2021, Christian Brauner wrote:

> 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/[email protected]
> Cc: Christoph Hellwig <[email protected]>
> Cc: David Howells <[email protected]>
> Cc: Al Viro <[email protected]>
> Cc: [email protected]
> Signed-off-by: Christian Brauner <[email protected]>


Reviewed-by: James Morris <[email protected]>


--
James Morris
<[email protected]>