linux/include/linux/mnt_idmapping.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_MNT_IDMAPPING_H
#define _LINUX_MNT_IDMAPPING_H

#include <linux/types.h>
#include <linux/uidgid.h>

struct mnt_idmap;
struct user_namespace;

extern struct mnt_idmap nop_mnt_idmap;
extern struct mnt_idmap invalid_mnt_idmap;
extern struct user_namespace init_user_ns;

vfsuid_t;

vfsgid_t;

static_assert(…);
static_assert(…);
static_assert(…);
static_assert(…);

#ifdef CONFIG_MULTIUSER
static inline uid_t __vfsuid_val(vfsuid_t uid)
{ … }

static inline gid_t __vfsgid_val(vfsgid_t gid)
{ … }
#else
static inline uid_t __vfsuid_val(vfsuid_t uid)
{
	return 0;
}

static inline gid_t __vfsgid_val(vfsgid_t gid)
{
	return 0;
}
#endif

static inline bool vfsuid_valid(vfsuid_t uid)
{ … }

static inline bool vfsgid_valid(vfsgid_t gid)
{ … }

static inline bool vfsuid_eq(vfsuid_t left, vfsuid_t right)
{ … }

static inline bool vfsgid_eq(vfsgid_t left, vfsgid_t right)
{ … }

/**
 * vfsuid_eq_kuid - check whether kuid and vfsuid have the same value
 * @vfsuid: the vfsuid to compare
 * @kuid: the kuid to compare
 *
 * Check whether @vfsuid and @kuid have the same values.
 *
 * Return: true if @vfsuid and @kuid have the same value, false if not.
 * Comparison between two invalid uids returns false.
 */
static inline bool vfsuid_eq_kuid(vfsuid_t vfsuid, kuid_t kuid)
{ … }

/**
 * vfsgid_eq_kgid - check whether kgid and vfsgid have the same value
 * @vfsgid: the vfsgid to compare
 * @kgid: the kgid to compare
 *
 * Check whether @vfsgid and @kgid have the same values.
 *
 * Return: true if @vfsgid and @kgid have the same value, false if not.
 * Comparison between two invalid gids returns false.
 */
static inline bool vfsgid_eq_kgid(vfsgid_t vfsgid, kgid_t kgid)
{ … }

/*
 * vfs{g,u}ids are created from k{g,u}ids.
 * We don't allow them to be created from regular {u,g}id.
 */
#define VFSUIDT_INIT(val) …
#define VFSGIDT_INIT(val) …

#define INVALID_VFSUID …
#define INVALID_VFSGID …

/*
 * Allow a vfs{g,u}id to be used as a k{g,u}id where we want to compare
 * whether the mapped value is identical to value of a k{g,u}id.
 */
#define AS_KUIDT(val) …
#define AS_KGIDT(val) …

int vfsgid_in_group_p(vfsgid_t vfsgid);

struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
void mnt_idmap_put(struct mnt_idmap *idmap);

vfsuid_t make_vfsuid(struct mnt_idmap *idmap,
		     struct user_namespace *fs_userns, kuid_t kuid);

vfsgid_t make_vfsgid(struct mnt_idmap *idmap,
		     struct user_namespace *fs_userns, kgid_t kgid);

kuid_t from_vfsuid(struct mnt_idmap *idmap,
		   struct user_namespace *fs_userns, vfsuid_t vfsuid);

kgid_t from_vfsgid(struct mnt_idmap *idmap,
		   struct user_namespace *fs_userns, vfsgid_t vfsgid);

/**
 * vfsuid_has_fsmapping - check whether a vfsuid maps into the filesystem
 * @idmap: the mount's idmapping
 * @fs_userns: the filesystem's idmapping
 * @vfsuid: vfsuid to be mapped
 *
 * Check whether @vfsuid has a mapping in the filesystem idmapping. Use this
 * function to check whether the filesystem idmapping has a mapping for
 * @vfsuid.
 *
 * Return: true if @vfsuid has a mapping in the filesystem, false if not.
 */
static inline bool vfsuid_has_fsmapping(struct mnt_idmap *idmap,
					struct user_namespace *fs_userns,
					vfsuid_t vfsuid)
{ … }

static inline bool vfsuid_has_mapping(struct user_namespace *userns,
				      vfsuid_t vfsuid)
{ … }

/**
 * vfsuid_into_kuid - convert vfsuid into kuid
 * @vfsuid: the vfsuid to convert
 *
 * This can be used when a vfsuid is committed as a kuid.
 *
 * Return: a kuid with the value of @vfsuid
 */
static inline kuid_t vfsuid_into_kuid(vfsuid_t vfsuid)
{ … }

/**
 * vfsgid_has_fsmapping - check whether a vfsgid maps into the filesystem
 * @idmap: the mount's idmapping
 * @fs_userns: the filesystem's idmapping
 * @vfsgid: vfsgid to be mapped
 *
 * Check whether @vfsgid has a mapping in the filesystem idmapping. Use this
 * function to check whether the filesystem idmapping has a mapping for
 * @vfsgid.
 *
 * Return: true if @vfsgid has a mapping in the filesystem, false if not.
 */
static inline bool vfsgid_has_fsmapping(struct mnt_idmap *idmap,
					struct user_namespace *fs_userns,
					vfsgid_t vfsgid)
{ … }

static inline bool vfsgid_has_mapping(struct user_namespace *userns,
				      vfsgid_t vfsgid)
{ … }

/**
 * vfsgid_into_kgid - convert vfsgid into kgid
 * @vfsgid: the vfsgid to convert
 *
 * This can be used when a vfsgid is committed as a kgid.
 *
 * Return: a kgid with the value of @vfsgid
 */
static inline kgid_t vfsgid_into_kgid(vfsgid_t vfsgid)
{ … }

/**
 * mapped_fsuid - return caller's fsuid mapped according to an idmapping
 * @idmap: the mount's idmapping
 * @fs_userns: the filesystem's idmapping
 *
 * Use this helper to initialize a new vfs or filesystem object based on
 * the caller's fsuid. A common example is initializing the i_uid field of
 * a newly allocated inode triggered by a creation event such as mkdir or
 * O_CREAT. Other examples include the allocation of quotas for a specific
 * user.
 *
 * Return: the caller's current fsuid mapped up according to @idmap.
 */
static inline kuid_t mapped_fsuid(struct mnt_idmap *idmap,
				  struct user_namespace *fs_userns)
{ … }

/**
 * mapped_fsgid - return caller's fsgid mapped according to an idmapping
 * @idmap: the mount's idmapping
 * @fs_userns: the filesystem's idmapping
 *
 * Use this helper to initialize a new vfs or filesystem object based on
 * the caller's fsgid. A common example is initializing the i_gid field of
 * a newly allocated inode triggered by a creation event such as mkdir or
 * O_CREAT. Other examples include the allocation of quotas for a specific
 * user.
 *
 * Return: the caller's current fsgid mapped up according to @idmap.
 */
static inline kgid_t mapped_fsgid(struct mnt_idmap *idmap,
				  struct user_namespace *fs_userns)
{ … }

#endif /* _LINUX_MNT_IDMAPPING_H */