Unverified Commit 234a3113 authored by Christian Brauner's avatar Christian Brauner Committed by Christian Brauner (Microsoft)
Browse files

fs: add two type safe mapping helpers 

Introduce i_{g,u}id_into_vfs{g,u}id(). They return vfs{g,u}id_t. This
makes it way harder to confused idmapped mount {g,u}ids with filesystem
{g,u}ids.

The two helpers will eventually replace the old non type safe
i_{g,u}id_into_mnt() helpers once we finished converting all places. Add
a comment noting that they will be removed in the future.

All new helpers are nops on non-idmapped mounts.

Link: https://lore.kernel.org/r/20220621141454.2914719-3-brauner@kernel.org


Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: default avatarSeth Forshee <sforshee@digitalocean.com>
Signed-off-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
parent 1e5267cd

include/linux/fs.h

+36 −2
Original line number Diff line number Diff line
@@ -1600,13 +1600,30 @@ static inline void i_gid_write(struct inode *inode, gid_t gid) 
 * @mnt_userns: user namespace of the mount the inode was found from

 * @inode: inode to map

 *

 * Note, this will eventually be removed completely in favor of the type-safe

 * i_uid_into_vfsuid().

 *

 * Return: the inode's i_uid mapped down according to @mnt_userns.

 * If the inode's i_uid has no mapping INVALID_UID is returned.

 */

static inline kuid_t i_uid_into_mnt(struct user_namespace *mnt_userns,

				    const struct inode *inode)

{

	return mapped_kuid_fs(mnt_userns, i_user_ns(inode), inode->i_uid);

	return AS_KUIDT(make_vfsuid(mnt_userns, i_user_ns(inode), inode->i_uid));

}



/**

 * i_uid_into_vfsuid - map an inode's i_uid down into a mnt_userns

 * @mnt_userns: user namespace of the mount the inode was found from

 * @inode: inode to map

 *

 * Return: whe inode's i_uid mapped down according to @mnt_userns.

 * If the inode's i_uid has no mapping INVALID_VFSUID is returned.

 */

static inline vfsuid_t i_uid_into_vfsuid(struct user_namespace *mnt_userns,

					 const struct inode *inode)

{

	return make_vfsuid(mnt_userns, i_user_ns(inode), inode->i_uid);

}



/**
@@ -1614,13 +1631,30 @@ static inline kuid_t i_uid_into_mnt(struct user_namespace *mnt_userns, 
 * @mnt_userns: user namespace of the mount the inode was found from

 * @inode: inode to map

 *

 * Note, this will eventually be removed completely in favor of the type-safe

 * i_gid_into_vfsgid().

 *

 * Return: the inode's i_gid mapped down according to @mnt_userns.

 * If the inode's i_gid has no mapping INVALID_GID is returned.

 */

static inline kgid_t i_gid_into_mnt(struct user_namespace *mnt_userns,

				    const struct inode *inode)

{

	return mapped_kgid_fs(mnt_userns, i_user_ns(inode), inode->i_gid);

	return AS_KGIDT(make_vfsgid(mnt_userns, i_user_ns(inode), inode->i_gid));

}



/**

 * i_gid_into_vfsgid - map an inode's i_gid down into a mnt_userns

 * @mnt_userns: user namespace of the mount the inode was found from

 * @inode: inode to map

 *

 * Return: the inode's i_gid mapped down according to @mnt_userns.

 * If the inode's i_gid has no mapping INVALID_VFSGID is returned.

 */

static inline vfsgid_t i_gid_into_vfsgid(struct user_namespace *mnt_userns,

					 const struct inode *inode)

{

	return make_vfsgid(mnt_userns, i_user_ns(inode), inode->i_gid);

}



/**