1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MNT_IDMAPPING_H
3 #define _LINUX_MNT_IDMAPPING_H
5 #include <linux/types.h>
6 #include <linux/uidgid.h>
11 extern struct mnt_idmap nop_mnt_idmap;
12 extern struct user_namespace init_user_ns;
22 static_assert(sizeof(vfsuid_t) == sizeof(kuid_t));
23 static_assert(sizeof(vfsgid_t) == sizeof(kgid_t));
24 static_assert(offsetof(vfsuid_t, val) == offsetof(kuid_t, val));
25 static_assert(offsetof(vfsgid_t, val) == offsetof(kgid_t, val));
27 #ifdef CONFIG_MULTIUSER
28 static inline uid_t __vfsuid_val(vfsuid_t uid)
33 static inline gid_t __vfsgid_val(vfsgid_t gid)
38 static inline uid_t __vfsuid_val(vfsuid_t uid)
43 static inline gid_t __vfsgid_val(vfsgid_t gid)
49 static inline bool vfsuid_valid(vfsuid_t uid)
51 return __vfsuid_val(uid) != (uid_t)-1;
54 static inline bool vfsgid_valid(vfsgid_t gid)
56 return __vfsgid_val(gid) != (gid_t)-1;
59 static inline bool vfsuid_eq(vfsuid_t left, vfsuid_t right)
61 return vfsuid_valid(left) && __vfsuid_val(left) == __vfsuid_val(right);
64 static inline bool vfsgid_eq(vfsgid_t left, vfsgid_t right)
66 return vfsgid_valid(left) && __vfsgid_val(left) == __vfsgid_val(right);
70 * vfsuid_eq_kuid - check whether kuid and vfsuid have the same value
71 * @vfsuid: the vfsuid to compare
72 * @kuid: the kuid to compare
74 * Check whether @vfsuid and @kuid have the same values.
76 * Return: true if @vfsuid and @kuid have the same value, false if not.
77 * Comparison between two invalid uids returns false.
79 static inline bool vfsuid_eq_kuid(vfsuid_t vfsuid, kuid_t kuid)
81 return vfsuid_valid(vfsuid) && __vfsuid_val(vfsuid) == __kuid_val(kuid);
85 * vfsgid_eq_kgid - check whether kgid and vfsgid have the same value
86 * @vfsgid: the vfsgid to compare
87 * @kgid: the kgid to compare
89 * Check whether @vfsgid and @kgid have the same values.
91 * Return: true if @vfsgid and @kgid have the same value, false if not.
92 * Comparison between two invalid gids returns false.
94 static inline bool vfsgid_eq_kgid(vfsgid_t vfsgid, kgid_t kgid)
96 return vfsgid_valid(vfsgid) && __vfsgid_val(vfsgid) == __kgid_val(kgid);
100 * vfs{g,u}ids are created from k{g,u}ids.
101 * We don't allow them to be created from regular {u,g}id.
103 #define VFSUIDT_INIT(val) (vfsuid_t){ __kuid_val(val) }
104 #define VFSGIDT_INIT(val) (vfsgid_t){ __kgid_val(val) }
106 #define INVALID_VFSUID VFSUIDT_INIT(INVALID_UID)
107 #define INVALID_VFSGID VFSGIDT_INIT(INVALID_GID)
110 * Allow a vfs{g,u}id to be used as a k{g,u}id where we want to compare
111 * whether the mapped value is identical to value of a k{g,u}id.
113 #define AS_KUIDT(val) (kuid_t){ __vfsuid_val(val) }
114 #define AS_KGIDT(val) (kgid_t){ __vfsgid_val(val) }
116 int vfsgid_in_group_p(vfsgid_t vfsgid);
118 vfsuid_t make_vfsuid(struct mnt_idmap *idmap,
119 struct user_namespace *fs_userns, kuid_t kuid);
121 vfsgid_t make_vfsgid(struct mnt_idmap *idmap,
122 struct user_namespace *fs_userns, kgid_t kgid);
124 kuid_t from_vfsuid(struct mnt_idmap *idmap,
125 struct user_namespace *fs_userns, vfsuid_t vfsuid);
127 kgid_t from_vfsgid(struct mnt_idmap *idmap,
128 struct user_namespace *fs_userns, vfsgid_t vfsgid);
131 * vfsuid_has_fsmapping - check whether a vfsuid maps into the filesystem
132 * @idmap: the mount's idmapping
133 * @fs_userns: the filesystem's idmapping
134 * @vfsuid: vfsuid to be mapped
136 * Check whether @vfsuid has a mapping in the filesystem idmapping. Use this
137 * function to check whether the filesystem idmapping has a mapping for
140 * Return: true if @vfsuid has a mapping in the filesystem, false if not.
142 static inline bool vfsuid_has_fsmapping(struct mnt_idmap *idmap,
143 struct user_namespace *fs_userns,
146 return uid_valid(from_vfsuid(idmap, fs_userns, vfsuid));
149 static inline bool vfsuid_has_mapping(struct user_namespace *userns,
152 return from_kuid(userns, AS_KUIDT(vfsuid)) != (uid_t)-1;
156 * vfsuid_into_kuid - convert vfsuid into kuid
157 * @vfsuid: the vfsuid to convert
159 * This can be used when a vfsuid is committed as a kuid.
161 * Return: a kuid with the value of @vfsuid
163 static inline kuid_t vfsuid_into_kuid(vfsuid_t vfsuid)
165 return AS_KUIDT(vfsuid);
169 * vfsgid_has_fsmapping - check whether a vfsgid maps into the filesystem
170 * @idmap: the mount's idmapping
171 * @fs_userns: the filesystem's idmapping
172 * @vfsgid: vfsgid to be mapped
174 * Check whether @vfsgid has a mapping in the filesystem idmapping. Use this
175 * function to check whether the filesystem idmapping has a mapping for
178 * Return: true if @vfsgid has a mapping in the filesystem, false if not.
180 static inline bool vfsgid_has_fsmapping(struct mnt_idmap *idmap,
181 struct user_namespace *fs_userns,
184 return gid_valid(from_vfsgid(idmap, fs_userns, vfsgid));
187 static inline bool vfsgid_has_mapping(struct user_namespace *userns,
190 return from_kgid(userns, AS_KGIDT(vfsgid)) != (gid_t)-1;
194 * vfsgid_into_kgid - convert vfsgid into kgid
195 * @vfsgid: the vfsgid to convert
197 * This can be used when a vfsgid is committed as a kgid.
199 * Return: a kgid with the value of @vfsgid
201 static inline kgid_t vfsgid_into_kgid(vfsgid_t vfsgid)
203 return AS_KGIDT(vfsgid);
207 * mapped_fsuid - return caller's fsuid mapped according to an idmapping
208 * @idmap: the mount's idmapping
209 * @fs_userns: the filesystem's idmapping
211 * Use this helper to initialize a new vfs or filesystem object based on
212 * the caller's fsuid. A common example is initializing the i_uid field of
213 * a newly allocated inode triggered by a creation event such as mkdir or
214 * O_CREAT. Other examples include the allocation of quotas for a specific
217 * Return: the caller's current fsuid mapped up according to @idmap.
219 static inline kuid_t mapped_fsuid(struct mnt_idmap *idmap,
220 struct user_namespace *fs_userns)
222 return from_vfsuid(idmap, fs_userns, VFSUIDT_INIT(current_fsuid()));
226 * mapped_fsgid - return caller's fsgid mapped according to an idmapping
227 * @idmap: the mount's idmapping
228 * @fs_userns: the filesystem's idmapping
230 * Use this helper to initialize a new vfs or filesystem object based on
231 * the caller's fsgid. A common example is initializing the i_gid field of
232 * a newly allocated inode triggered by a creation event such as mkdir or
233 * O_CREAT. Other examples include the allocation of quotas for a specific
236 * Return: the caller's current fsgid mapped up according to @idmap.
238 static inline kgid_t mapped_fsgid(struct mnt_idmap *idmap,
239 struct user_namespace *fs_userns)
241 return from_vfsgid(idmap, fs_userns, VFSGIDT_INIT(current_fsgid()));
244 bool check_fsmapping(const struct mnt_idmap *idmap,
245 const struct super_block *sb);
247 #endif /* _LINUX_MNT_IDMAPPING_H */