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1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_MNT_IDMAPPING_H | |
3 | #define _LINUX_MNT_IDMAPPING_H | |
4 | ||
5 | #include <linux/types.h> | |
6 | #include <linux/uidgid.h> | |
7 | ||
256c8aed | 8 | struct mnt_idmap; |
a793d79e | 9 | struct user_namespace; |
256c8aed CB |
10 | |
11 | extern struct mnt_idmap nop_mnt_idmap; | |
ffcdc4c6 | 12 | extern struct mnt_idmap invalid_mnt_idmap; |
a793d79e CB |
13 | extern struct user_namespace init_user_ns; |
14 | ||
1e5267cd CB |
15 | typedef struct { |
16 | uid_t val; | |
17 | } vfsuid_t; | |
18 | ||
19 | typedef struct { | |
20 | gid_t val; | |
21 | } vfsgid_t; | |
22 | ||
45c31150 CB |
23 | static_assert(sizeof(vfsuid_t) == sizeof(kuid_t)); |
24 | static_assert(sizeof(vfsgid_t) == sizeof(kgid_t)); | |
25 | static_assert(offsetof(vfsuid_t, val) == offsetof(kuid_t, val)); | |
26 | static_assert(offsetof(vfsgid_t, val) == offsetof(kgid_t, val)); | |
27 | ||
1e5267cd CB |
28 | #ifdef CONFIG_MULTIUSER |
29 | static inline uid_t __vfsuid_val(vfsuid_t uid) | |
30 | { | |
31 | return uid.val; | |
32 | } | |
33 | ||
34 | static inline gid_t __vfsgid_val(vfsgid_t gid) | |
35 | { | |
36 | return gid.val; | |
37 | } | |
38 | #else | |
39 | static inline uid_t __vfsuid_val(vfsuid_t uid) | |
40 | { | |
41 | return 0; | |
42 | } | |
43 | ||
44 | static inline gid_t __vfsgid_val(vfsgid_t gid) | |
45 | { | |
46 | return 0; | |
47 | } | |
48 | #endif | |
49 | ||
50 | static inline bool vfsuid_valid(vfsuid_t uid) | |
51 | { | |
52 | return __vfsuid_val(uid) != (uid_t)-1; | |
53 | } | |
54 | ||
55 | static inline bool vfsgid_valid(vfsgid_t gid) | |
56 | { | |
57 | return __vfsgid_val(gid) != (gid_t)-1; | |
58 | } | |
59 | ||
60 | static inline bool vfsuid_eq(vfsuid_t left, vfsuid_t right) | |
61 | { | |
4d0548a7 | 62 | return vfsuid_valid(left) && __vfsuid_val(left) == __vfsuid_val(right); |
1e5267cd CB |
63 | } |
64 | ||
65 | static inline bool vfsgid_eq(vfsgid_t left, vfsgid_t right) | |
66 | { | |
4d0548a7 | 67 | return vfsgid_valid(left) && __vfsgid_val(left) == __vfsgid_val(right); |
1e5267cd CB |
68 | } |
69 | ||
70 | /** | |
71 | * vfsuid_eq_kuid - check whether kuid and vfsuid have the same value | |
1e5267cd | 72 | * @vfsuid: the vfsuid to compare |
77940f0d | 73 | * @kuid: the kuid to compare |
1e5267cd | 74 | * |
77940f0d | 75 | * Check whether @vfsuid and @kuid have the same values. |
1e5267cd | 76 | * |
77940f0d | 77 | * Return: true if @vfsuid and @kuid have the same value, false if not. |
4d0548a7 | 78 | * Comparison between two invalid uids returns false. |
1e5267cd CB |
79 | */ |
80 | static inline bool vfsuid_eq_kuid(vfsuid_t vfsuid, kuid_t kuid) | |
81 | { | |
4d0548a7 | 82 | return vfsuid_valid(vfsuid) && __vfsuid_val(vfsuid) == __kuid_val(kuid); |
1e5267cd CB |
83 | } |
84 | ||
85 | /** | |
86 | * vfsgid_eq_kgid - check whether kgid and vfsgid have the same value | |
1e5267cd | 87 | * @vfsgid: the vfsgid to compare |
77940f0d | 88 | * @kgid: the kgid to compare |
1e5267cd | 89 | * |
77940f0d | 90 | * Check whether @vfsgid and @kgid have the same values. |
1e5267cd | 91 | * |
77940f0d | 92 | * Return: true if @vfsgid and @kgid have the same value, false if not. |
4d0548a7 | 93 | * Comparison between two invalid gids returns false. |
1e5267cd | 94 | */ |
77940f0d | 95 | static inline bool vfsgid_eq_kgid(vfsgid_t vfsgid, kgid_t kgid) |
1e5267cd | 96 | { |
4d0548a7 | 97 | return vfsgid_valid(vfsgid) && __vfsgid_val(vfsgid) == __kgid_val(kgid); |
1e5267cd CB |
98 | } |
99 | ||
100 | /* | |
101 | * vfs{g,u}ids are created from k{g,u}ids. | |
102 | * We don't allow them to be created from regular {u,g}id. | |
103 | */ | |
104 | #define VFSUIDT_INIT(val) (vfsuid_t){ __kuid_val(val) } | |
105 | #define VFSGIDT_INIT(val) (vfsgid_t){ __kgid_val(val) } | |
106 | ||
107 | #define INVALID_VFSUID VFSUIDT_INIT(INVALID_UID) | |
108 | #define INVALID_VFSGID VFSGIDT_INIT(INVALID_GID) | |
109 | ||
110 | /* | |
111 | * Allow a vfs{g,u}id to be used as a k{g,u}id where we want to compare | |
112 | * whether the mapped value is identical to value of a k{g,u}id. | |
113 | */ | |
114 | #define AS_KUIDT(val) (kuid_t){ __vfsuid_val(val) } | |
115 | #define AS_KGIDT(val) (kgid_t){ __vfsgid_val(val) } | |
116 | ||
3707d84c | 117 | int vfsgid_in_group_p(vfsgid_t vfsgid); |
1e5267cd | 118 | |
1b903446 AM |
119 | struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap); |
120 | void mnt_idmap_put(struct mnt_idmap *idmap); | |
121 | ||
3707d84c CB |
122 | vfsuid_t make_vfsuid(struct mnt_idmap *idmap, |
123 | struct user_namespace *fs_userns, kuid_t kuid); | |
1ac2a410 | 124 | |
3707d84c CB |
125 | vfsgid_t make_vfsgid(struct mnt_idmap *idmap, |
126 | struct user_namespace *fs_userns, kgid_t kgid); | |
1ac2a410 | 127 | |
3707d84c CB |
128 | kuid_t from_vfsuid(struct mnt_idmap *idmap, |
129 | struct user_namespace *fs_userns, vfsuid_t vfsuid); | |
1e5267cd | 130 | |
3707d84c CB |
131 | kgid_t from_vfsgid(struct mnt_idmap *idmap, |
132 | struct user_namespace *fs_userns, vfsgid_t vfsgid); | |
1ac2a410 | 133 | |
1e5267cd CB |
134 | /** |
135 | * vfsuid_has_fsmapping - check whether a vfsuid maps into the filesystem | |
4d7ca409 | 136 | * @idmap: the mount's idmapping |
1e5267cd CB |
137 | * @fs_userns: the filesystem's idmapping |
138 | * @vfsuid: vfsuid to be mapped | |
139 | * | |
140 | * Check whether @vfsuid has a mapping in the filesystem idmapping. Use this | |
141 | * function to check whether the filesystem idmapping has a mapping for | |
142 | * @vfsuid. | |
143 | * | |
144 | * Return: true if @vfsuid has a mapping in the filesystem, false if not. | |
145 | */ | |
4d7ca409 | 146 | static inline bool vfsuid_has_fsmapping(struct mnt_idmap *idmap, |
1e5267cd CB |
147 | struct user_namespace *fs_userns, |
148 | vfsuid_t vfsuid) | |
149 | { | |
4d7ca409 | 150 | return uid_valid(from_vfsuid(idmap, fs_userns, vfsuid)); |
1e5267cd CB |
151 | } |
152 | ||
9c4f28dd CB |
153 | static inline bool vfsuid_has_mapping(struct user_namespace *userns, |
154 | vfsuid_t vfsuid) | |
155 | { | |
156 | return from_kuid(userns, AS_KUIDT(vfsuid)) != (uid_t)-1; | |
157 | } | |
158 | ||
c9fa2b07 CB |
159 | /** |
160 | * vfsuid_into_kuid - convert vfsuid into kuid | |
161 | * @vfsuid: the vfsuid to convert | |
162 | * | |
163 | * This can be used when a vfsuid is committed as a kuid. | |
164 | * | |
165 | * Return: a kuid with the value of @vfsuid | |
166 | */ | |
167 | static inline kuid_t vfsuid_into_kuid(vfsuid_t vfsuid) | |
168 | { | |
169 | return AS_KUIDT(vfsuid); | |
170 | } | |
171 | ||
1e5267cd CB |
172 | /** |
173 | * vfsgid_has_fsmapping - check whether a vfsgid maps into the filesystem | |
4d7ca409 | 174 | * @idmap: the mount's idmapping |
1e5267cd CB |
175 | * @fs_userns: the filesystem's idmapping |
176 | * @vfsgid: vfsgid to be mapped | |
177 | * | |
178 | * Check whether @vfsgid has a mapping in the filesystem idmapping. Use this | |
179 | * function to check whether the filesystem idmapping has a mapping for | |
180 | * @vfsgid. | |
181 | * | |
182 | * Return: true if @vfsgid has a mapping in the filesystem, false if not. | |
183 | */ | |
4d7ca409 | 184 | static inline bool vfsgid_has_fsmapping(struct mnt_idmap *idmap, |
1e5267cd CB |
185 | struct user_namespace *fs_userns, |
186 | vfsgid_t vfsgid) | |
187 | { | |
4d7ca409 | 188 | return gid_valid(from_vfsgid(idmap, fs_userns, vfsgid)); |
1ac2a410 CB |
189 | } |
190 | ||
9c4f28dd CB |
191 | static inline bool vfsgid_has_mapping(struct user_namespace *userns, |
192 | vfsgid_t vfsgid) | |
193 | { | |
194 | return from_kgid(userns, AS_KGIDT(vfsgid)) != (gid_t)-1; | |
195 | } | |
196 | ||
c9fa2b07 CB |
197 | /** |
198 | * vfsgid_into_kgid - convert vfsgid into kgid | |
199 | * @vfsgid: the vfsgid to convert | |
200 | * | |
201 | * This can be used when a vfsgid is committed as a kgid. | |
202 | * | |
203 | * Return: a kgid with the value of @vfsgid | |
204 | */ | |
205 | static inline kgid_t vfsgid_into_kgid(vfsgid_t vfsgid) | |
206 | { | |
207 | return AS_KGIDT(vfsgid); | |
208 | } | |
209 | ||
a793d79e | 210 | /** |
c14329d3 CB |
211 | * mapped_fsuid - return caller's fsuid mapped according to an idmapping |
212 | * @idmap: the mount's idmapping | |
209188ce | 213 | * @fs_userns: the filesystem's idmapping |
a793d79e CB |
214 | * |
215 | * Use this helper to initialize a new vfs or filesystem object based on | |
216 | * the caller's fsuid. A common example is initializing the i_uid field of | |
217 | * a newly allocated inode triggered by a creation event such as mkdir or | |
218 | * O_CREAT. Other examples include the allocation of quotas for a specific | |
219 | * user. | |
220 | * | |
c14329d3 | 221 | * Return: the caller's current fsuid mapped up according to @idmap. |
a793d79e | 222 | */ |
c14329d3 | 223 | static inline kuid_t mapped_fsuid(struct mnt_idmap *idmap, |
209188ce | 224 | struct user_namespace *fs_userns) |
a793d79e | 225 | { |
4d7ca409 | 226 | return from_vfsuid(idmap, fs_userns, VFSUIDT_INIT(current_fsuid())); |
a793d79e CB |
227 | } |
228 | ||
229 | /** | |
c14329d3 CB |
230 | * mapped_fsgid - return caller's fsgid mapped according to an idmapping |
231 | * @idmap: the mount's idmapping | |
209188ce | 232 | * @fs_userns: the filesystem's idmapping |
a793d79e CB |
233 | * |
234 | * Use this helper to initialize a new vfs or filesystem object based on | |
235 | * the caller's fsgid. A common example is initializing the i_gid field of | |
236 | * a newly allocated inode triggered by a creation event such as mkdir or | |
237 | * O_CREAT. Other examples include the allocation of quotas for a specific | |
238 | * user. | |
239 | * | |
c14329d3 | 240 | * Return: the caller's current fsgid mapped up according to @idmap. |
a793d79e | 241 | */ |
c14329d3 | 242 | static inline kgid_t mapped_fsgid(struct mnt_idmap *idmap, |
209188ce | 243 | struct user_namespace *fs_userns) |
a793d79e | 244 | { |
4d7ca409 | 245 | return from_vfsgid(idmap, fs_userns, VFSGIDT_INIT(current_fsgid())); |
a793d79e CB |
246 | } |
247 | ||
248 | #endif /* _LINUX_MNT_IDMAPPING_H */ |