diff mbox series

[v5,29/42] ioctl: handle idmapped mounts

Message ID 20210112220124.837960-30-christian.brauner@ubuntu.com
State Superseded
Headers show
Series idmapped mounts | expand

Commit Message

Christian Brauner Jan. 12, 2021, 10:01 p.m. UTC 
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.

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 */
unchanged

/* v4 */
- Serge Hallyn <serge@hallyn.com>:
  - Use "mnt_userns" to refer to a vfsmount's userns everywhere to make
    terminology consistent.

/* v5 */
base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837

- Christoph Hellwig <hch@lst.de>:
  - Use new file_userns_helper().
---
 fs/remap_range.c   | 7 +++++--
 fs/verity/enable.c | 2 +-
 2 files changed, 6 insertions(+), 3 deletions(-)

Comments

Christoph Hellwig Jan. 19, 2021, 9:44 a.m. UTC | #1 
On Tue, Jan 12, 2021 at 11:01:11PM +0100, 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.

Looks good, although file_permission would help here as well..

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/fs/remap_range.c b/fs/remap_range.c
index 29a4a4dbfe12..dc68394ec9a1 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_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;
 }
diff --git a/fs/verity/enable.c b/fs/verity/enable.c
index 6809cf8a99b7..9a221e368fa6 100644
--- a/fs/verity/enable.c
+++ b/fs/verity/enable.c
@@ -369,7 +369,7 @@  int fsverity_ioctl_enable(struct file *filp, const void __user *uarg)
 	 * has verity enabled, and to stabilize the data being hashed.
 	 */
 
-	err = inode_permission(&init_user_ns, inode, MAY_WRITE);
+	err = inode_permission(file_user_ns(filp), inode, MAY_WRITE);
 	if (err)
 		return err;