2021-01-21 14:54:07

by Christian Brauner

Subject: [PATCH v6 21/40] ioctl: handle idmapped mounts

Enable generic ioctls to handle idmapped mounts by passing down the
mount's user namespace. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

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]
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
---
/* v2 */
patch introduced

/* v3 */
unchanged

/* v4 */
- Serge Hallyn <[email protected]>:
- Use "mnt_userns" to refer to a vfsmount's userns everywhere to make
terminology consistent.

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

- Christoph Hellwig <[email protected]>:
- Use new file_mnt_user_ns() helper.

/* v6 */
base-commit: 19c329f6808995b142b3966301f217c831e7cf31

- Christoph Hellwig <[email protected]>:
- Make use of file_permission() helper.
---
fs/remap_range.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/remap_range.c b/fs/remap_range.c
index 29a4a4dbfe12..e4a5fdd7ad7b 100644
--- a/fs/remap_range.c
+++ b/fs/remap_range.c
@@ -432,13 +432,16 @@ EXPORT_SYMBOL(vfs_clone_file_range);
/* Check whether we are allowed to dedupe the destination file */
static bool allow_file_dedupe(struct file *file)
{
+ struct user_namespace *mnt_userns = file_mnt_user_ns(file);
+ struct inode *inode = file_inode(file);
+
if (capable(CAP_SYS_ADMIN))
return true;
if (file->f_mode & FMODE_WRITE)
return true;
- if (uid_eq(current_fsuid(), file_inode(file)->i_uid))
+ if (uid_eq(current_fsuid(), i_uid_into_mnt(mnt_userns, inode)))
return true;
- if (!inode_permission(&init_user_ns, file_inode(file), MAY_WRITE))
+ if (!inode_permission(mnt_userns, inode, MAY_WRITE))
return true;
return false;
}
--
2.30.0

2021-01-22 05:12:14

by James Morris

Subject: Re: [PATCH v6 21/40] ioctl: handle idmapped mounts

On Thu, 21 Jan 2021, Christian Brauner wrote:

> Enable generic ioctls to handle idmapped mounts by passing down the
> mount's user namespace. If the initial user namespace is passed nothing
> changes so non-idmapped mounts will see identical behavior as before.
>
> 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]
> Reviewed-by: Christoph Hellwig <[email protected]>
> Signed-off-by: Christian Brauner <[email protected]>


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

--
James Morris
<[email protected]>