fs: port privilege checking helpers to mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/capability.h b/include/linux/capability.h
index 0a8ba82ef1af..03c2a613ad40 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -249,9 +249,9 @@ static inline bool ns_capable_setid(struct user_namespace *ns, int cap)
 }
 #endif /* CONFIG_MULTIUSER */
 bool privileged_wrt_inode_uidgid(struct user_namespace *ns,
-				 struct user_namespace *mnt_userns,
+				 struct mnt_idmap *idmap,
 				 const struct inode *inode);
-bool capable_wrt_inode_uidgid(struct user_namespace *mnt_userns,
+bool capable_wrt_inode_uidgid(struct mnt_idmap *idmap,
 			      const struct inode *inode, int cap);
 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
 extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);