249 lines
6.9 KiB
C
249 lines
6.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_MNT_IDMAPPING_H
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#define _LINUX_MNT_IDMAPPING_H
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#include <linux/types.h>
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#include <linux/uidgid.h>
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struct mnt_idmap;
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struct user_namespace;
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extern struct mnt_idmap nop_mnt_idmap;
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extern struct mnt_idmap invalid_mnt_idmap;
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extern struct user_namespace init_user_ns;
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typedef struct {
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uid_t val;
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} vfsuid_t;
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typedef struct {
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gid_t val;
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} vfsgid_t;
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static_assert(sizeof(vfsuid_t) == sizeof(kuid_t));
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static_assert(sizeof(vfsgid_t) == sizeof(kgid_t));
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static_assert(offsetof(vfsuid_t, val) == offsetof(kuid_t, val));
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static_assert(offsetof(vfsgid_t, val) == offsetof(kgid_t, val));
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#ifdef CONFIG_MULTIUSER
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static inline uid_t __vfsuid_val(vfsuid_t uid)
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{
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return uid.val;
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}
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static inline gid_t __vfsgid_val(vfsgid_t gid)
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{
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return gid.val;
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}
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#else
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static inline uid_t __vfsuid_val(vfsuid_t uid)
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{
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return 0;
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}
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static inline gid_t __vfsgid_val(vfsgid_t gid)
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{
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return 0;
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}
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#endif
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static inline bool vfsuid_valid(vfsuid_t uid)
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{
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return __vfsuid_val(uid) != (uid_t)-1;
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}
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static inline bool vfsgid_valid(vfsgid_t gid)
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{
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return __vfsgid_val(gid) != (gid_t)-1;
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}
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static inline bool vfsuid_eq(vfsuid_t left, vfsuid_t right)
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{
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return vfsuid_valid(left) && __vfsuid_val(left) == __vfsuid_val(right);
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}
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static inline bool vfsgid_eq(vfsgid_t left, vfsgid_t right)
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{
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return vfsgid_valid(left) && __vfsgid_val(left) == __vfsgid_val(right);
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}
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/**
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* vfsuid_eq_kuid - check whether kuid and vfsuid have the same value
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* @vfsuid: the vfsuid to compare
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* @kuid: the kuid to compare
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*
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* Check whether @vfsuid and @kuid have the same values.
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*
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* Return: true if @vfsuid and @kuid have the same value, false if not.
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* Comparison between two invalid uids returns false.
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*/
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static inline bool vfsuid_eq_kuid(vfsuid_t vfsuid, kuid_t kuid)
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{
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return vfsuid_valid(vfsuid) && __vfsuid_val(vfsuid) == __kuid_val(kuid);
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}
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/**
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* vfsgid_eq_kgid - check whether kgid and vfsgid have the same value
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* @vfsgid: the vfsgid to compare
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* @kgid: the kgid to compare
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*
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* Check whether @vfsgid and @kgid have the same values.
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*
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* Return: true if @vfsgid and @kgid have the same value, false if not.
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* Comparison between two invalid gids returns false.
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*/
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static inline bool vfsgid_eq_kgid(vfsgid_t vfsgid, kgid_t kgid)
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{
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return vfsgid_valid(vfsgid) && __vfsgid_val(vfsgid) == __kgid_val(kgid);
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}
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/*
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* vfs{g,u}ids are created from k{g,u}ids.
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* We don't allow them to be created from regular {u,g}id.
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*/
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#define VFSUIDT_INIT(val) (vfsuid_t){ __kuid_val(val) }
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#define VFSGIDT_INIT(val) (vfsgid_t){ __kgid_val(val) }
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#define INVALID_VFSUID VFSUIDT_INIT(INVALID_UID)
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#define INVALID_VFSGID VFSGIDT_INIT(INVALID_GID)
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/*
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* Allow a vfs{g,u}id to be used as a k{g,u}id where we want to compare
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* whether the mapped value is identical to value of a k{g,u}id.
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*/
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#define AS_KUIDT(val) (kuid_t){ __vfsuid_val(val) }
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#define AS_KGIDT(val) (kgid_t){ __vfsgid_val(val) }
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int vfsgid_in_group_p(vfsgid_t vfsgid);
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struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
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void mnt_idmap_put(struct mnt_idmap *idmap);
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vfsuid_t make_vfsuid(struct mnt_idmap *idmap,
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struct user_namespace *fs_userns, kuid_t kuid);
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vfsgid_t make_vfsgid(struct mnt_idmap *idmap,
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struct user_namespace *fs_userns, kgid_t kgid);
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kuid_t from_vfsuid(struct mnt_idmap *idmap,
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struct user_namespace *fs_userns, vfsuid_t vfsuid);
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kgid_t from_vfsgid(struct mnt_idmap *idmap,
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struct user_namespace *fs_userns, vfsgid_t vfsgid);
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/**
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* vfsuid_has_fsmapping - check whether a vfsuid maps into the filesystem
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* @idmap: the mount's idmapping
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* @fs_userns: the filesystem's idmapping
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* @vfsuid: vfsuid to be mapped
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*
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* Check whether @vfsuid has a mapping in the filesystem idmapping. Use this
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* function to check whether the filesystem idmapping has a mapping for
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* @vfsuid.
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*
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* Return: true if @vfsuid has a mapping in the filesystem, false if not.
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*/
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static inline bool vfsuid_has_fsmapping(struct mnt_idmap *idmap,
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struct user_namespace *fs_userns,
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vfsuid_t vfsuid)
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{
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return uid_valid(from_vfsuid(idmap, fs_userns, vfsuid));
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}
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static inline bool vfsuid_has_mapping(struct user_namespace *userns,
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vfsuid_t vfsuid)
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{
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return from_kuid(userns, AS_KUIDT(vfsuid)) != (uid_t)-1;
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}
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/**
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* vfsuid_into_kuid - convert vfsuid into kuid
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* @vfsuid: the vfsuid to convert
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*
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* This can be used when a vfsuid is committed as a kuid.
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*
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* Return: a kuid with the value of @vfsuid
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*/
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static inline kuid_t vfsuid_into_kuid(vfsuid_t vfsuid)
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{
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return AS_KUIDT(vfsuid);
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}
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/**
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* vfsgid_has_fsmapping - check whether a vfsgid maps into the filesystem
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* @idmap: the mount's idmapping
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* @fs_userns: the filesystem's idmapping
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* @vfsgid: vfsgid to be mapped
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*
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* Check whether @vfsgid has a mapping in the filesystem idmapping. Use this
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* function to check whether the filesystem idmapping has a mapping for
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* @vfsgid.
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*
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* Return: true if @vfsgid has a mapping in the filesystem, false if not.
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*/
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static inline bool vfsgid_has_fsmapping(struct mnt_idmap *idmap,
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struct user_namespace *fs_userns,
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vfsgid_t vfsgid)
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{
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return gid_valid(from_vfsgid(idmap, fs_userns, vfsgid));
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}
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static inline bool vfsgid_has_mapping(struct user_namespace *userns,
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vfsgid_t vfsgid)
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{
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return from_kgid(userns, AS_KGIDT(vfsgid)) != (gid_t)-1;
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}
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/**
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* vfsgid_into_kgid - convert vfsgid into kgid
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* @vfsgid: the vfsgid to convert
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*
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* This can be used when a vfsgid is committed as a kgid.
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*
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* Return: a kgid with the value of @vfsgid
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*/
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static inline kgid_t vfsgid_into_kgid(vfsgid_t vfsgid)
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{
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return AS_KGIDT(vfsgid);
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}
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/**
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* mapped_fsuid - return caller's fsuid mapped according to an idmapping
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* @idmap: the mount's idmapping
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* @fs_userns: the filesystem's idmapping
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*
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* Use this helper to initialize a new vfs or filesystem object based on
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* the caller's fsuid. A common example is initializing the i_uid field of
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* a newly allocated inode triggered by a creation event such as mkdir or
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* O_CREAT. Other examples include the allocation of quotas for a specific
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* user.
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*
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* Return: the caller's current fsuid mapped up according to @idmap.
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*/
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static inline kuid_t mapped_fsuid(struct mnt_idmap *idmap,
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struct user_namespace *fs_userns)
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{
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return from_vfsuid(idmap, fs_userns, VFSUIDT_INIT(current_fsuid()));
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}
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/**
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* mapped_fsgid - return caller's fsgid mapped according to an idmapping
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* @idmap: the mount's idmapping
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* @fs_userns: the filesystem's idmapping
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*
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* Use this helper to initialize a new vfs or filesystem object based on
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* the caller's fsgid. A common example is initializing the i_gid field of
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* a newly allocated inode triggered by a creation event such as mkdir or
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* O_CREAT. Other examples include the allocation of quotas for a specific
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* user.
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*
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* Return: the caller's current fsgid mapped up according to @idmap.
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*/
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static inline kgid_t mapped_fsgid(struct mnt_idmap *idmap,
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struct user_namespace *fs_userns)
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{
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return from_vfsgid(idmap, fs_userns, VFSGIDT_INIT(current_fsgid()));
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}
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#endif /* _LINUX_MNT_IDMAPPING_H */
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