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a793d79e CB |
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; | |
a793d79e CB |
12 | extern struct user_namespace init_user_ns; |
13 | ||
1e5267cd CB |
14 | typedef struct { |
15 | uid_t val; | |
16 | } vfsuid_t; | |
17 | ||
18 | typedef struct { | |
19 | gid_t val; | |
20 | } vfsgid_t; | |
21 | ||
45c31150 CB |
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)); | |
26 | ||
1e5267cd CB |
27 | #ifdef CONFIG_MULTIUSER |
28 | static inline uid_t __vfsuid_val(vfsuid_t uid) | |
29 | { | |
30 | return uid.val; | |
31 | } | |
32 | ||
33 | static inline gid_t __vfsgid_val(vfsgid_t gid) | |
34 | { | |
35 | return gid.val; | |
36 | } | |
37 | #else | |
38 | static inline uid_t __vfsuid_val(vfsuid_t uid) | |
39 | { | |
40 | return 0; | |
41 | } | |
42 | ||
43 | static inline gid_t __vfsgid_val(vfsgid_t gid) | |
44 | { | |
45 | return 0; | |
46 | } | |
47 | #endif | |
48 | ||
49 | static inline bool vfsuid_valid(vfsuid_t uid) | |
50 | { | |
51 | return __vfsuid_val(uid) != (uid_t)-1; | |
52 | } | |
53 | ||
54 | static inline bool vfsgid_valid(vfsgid_t gid) | |
55 | { | |
56 | return __vfsgid_val(gid) != (gid_t)-1; | |
57 | } | |
58 | ||
59 | static inline bool vfsuid_eq(vfsuid_t left, vfsuid_t right) | |
60 | { | |
4d0548a7 | 61 | return vfsuid_valid(left) && __vfsuid_val(left) == __vfsuid_val(right); |
1e5267cd CB |
62 | } |
63 | ||
64 | static inline bool vfsgid_eq(vfsgid_t left, vfsgid_t right) | |
65 | { | |
4d0548a7 | 66 | return vfsgid_valid(left) && __vfsgid_val(left) == __vfsgid_val(right); |
1e5267cd CB |
67 | } |
68 | ||
69 | /** | |
70 | * vfsuid_eq_kuid - check whether kuid and vfsuid have the same value | |
1e5267cd | 71 | * @vfsuid: the vfsuid to compare |
77940f0d | 72 | * @kuid: the kuid to compare |
1e5267cd | 73 | * |
77940f0d | 74 | * Check whether @vfsuid and @kuid have the same values. |
1e5267cd | 75 | * |
77940f0d | 76 | * Return: true if @vfsuid and @kuid have the same value, false if not. |
4d0548a7 | 77 | * Comparison between two invalid uids returns false. |
1e5267cd CB |
78 | */ |
79 | static inline bool vfsuid_eq_kuid(vfsuid_t vfsuid, kuid_t kuid) | |
80 | { | |
4d0548a7 | 81 | return vfsuid_valid(vfsuid) && __vfsuid_val(vfsuid) == __kuid_val(kuid); |
1e5267cd CB |
82 | } |
83 | ||
84 | /** | |
85 | * vfsgid_eq_kgid - check whether kgid and vfsgid have the same value | |
1e5267cd | 86 | * @vfsgid: the vfsgid to compare |
77940f0d | 87 | * @kgid: the kgid to compare |
1e5267cd | 88 | * |
77940f0d | 89 | * Check whether @vfsgid and @kgid have the same values. |
1e5267cd | 90 | * |
77940f0d | 91 | * Return: true if @vfsgid and @kgid have the same value, false if not. |
4d0548a7 | 92 | * Comparison between two invalid gids returns false. |
1e5267cd | 93 | */ |
77940f0d | 94 | static inline bool vfsgid_eq_kgid(vfsgid_t vfsgid, kgid_t kgid) |
1e5267cd | 95 | { |
4d0548a7 | 96 | return vfsgid_valid(vfsgid) && __vfsgid_val(vfsgid) == __kgid_val(kgid); |
1e5267cd CB |
97 | } |
98 | ||
99 | /* | |
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. | |
102 | */ | |
103 | #define VFSUIDT_INIT(val) (vfsuid_t){ __kuid_val(val) } | |
104 | #define VFSGIDT_INIT(val) (vfsgid_t){ __kgid_val(val) } | |
105 | ||
106 | #define INVALID_VFSUID VFSUIDT_INIT(INVALID_UID) | |
107 | #define INVALID_VFSGID VFSGIDT_INIT(INVALID_GID) | |
108 | ||
109 | /* | |
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. | |
112 | */ | |
113 | #define AS_KUIDT(val) (kuid_t){ __vfsuid_val(val) } | |
114 | #define AS_KGIDT(val) (kgid_t){ __vfsgid_val(val) } | |
115 | ||
3707d84c | 116 | int vfsgid_in_group_p(vfsgid_t vfsgid); |
1e5267cd | 117 | |
3707d84c CB |
118 | vfsuid_t make_vfsuid(struct mnt_idmap *idmap, |
119 | struct user_namespace *fs_userns, kuid_t kuid); | |
1ac2a410 | 120 | |
3707d84c CB |
121 | vfsgid_t make_vfsgid(struct mnt_idmap *idmap, |
122 | struct user_namespace *fs_userns, kgid_t kgid); | |
1ac2a410 | 123 | |
3707d84c CB |
124 | kuid_t from_vfsuid(struct mnt_idmap *idmap, |
125 | struct user_namespace *fs_userns, vfsuid_t vfsuid); | |
1e5267cd | 126 | |
3707d84c CB |
127 | kgid_t from_vfsgid(struct mnt_idmap *idmap, |
128 | struct user_namespace *fs_userns, vfsgid_t vfsgid); | |
1ac2a410 | 129 | |
1e5267cd CB |
130 | /** |
131 | * vfsuid_has_fsmapping - check whether a vfsuid maps into the filesystem | |
4d7ca409 | 132 | * @idmap: the mount's idmapping |
1e5267cd CB |
133 | * @fs_userns: the filesystem's idmapping |
134 | * @vfsuid: vfsuid to be mapped | |
135 | * | |
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 | |
138 | * @vfsuid. | |
139 | * | |
140 | * Return: true if @vfsuid has a mapping in the filesystem, false if not. | |
141 | */ | |
4d7ca409 | 142 | static inline bool vfsuid_has_fsmapping(struct mnt_idmap *idmap, |
1e5267cd CB |
143 | struct user_namespace *fs_userns, |
144 | vfsuid_t vfsuid) | |
145 | { | |
4d7ca409 | 146 | return uid_valid(from_vfsuid(idmap, fs_userns, vfsuid)); |
1e5267cd CB |
147 | } |
148 | ||
9c4f28dd CB |
149 | static inline bool vfsuid_has_mapping(struct user_namespace *userns, |
150 | vfsuid_t vfsuid) | |
151 | { | |
152 | return from_kuid(userns, AS_KUIDT(vfsuid)) != (uid_t)-1; | |
153 | } | |
154 | ||
c9fa2b07 CB |
155 | /** |
156 | * vfsuid_into_kuid - convert vfsuid into kuid | |
157 | * @vfsuid: the vfsuid to convert | |
158 | * | |
159 | * This can be used when a vfsuid is committed as a kuid. | |
160 | * | |
161 | * Return: a kuid with the value of @vfsuid | |
162 | */ | |
163 | static inline kuid_t vfsuid_into_kuid(vfsuid_t vfsuid) | |
164 | { | |
165 | return AS_KUIDT(vfsuid); | |
166 | } | |
167 | ||
1e5267cd CB |
168 | /** |
169 | * vfsgid_has_fsmapping - check whether a vfsgid maps into the filesystem | |
4d7ca409 | 170 | * @idmap: the mount's idmapping |
1e5267cd CB |
171 | * @fs_userns: the filesystem's idmapping |
172 | * @vfsgid: vfsgid to be mapped | |
173 | * | |
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 | |
176 | * @vfsgid. | |
177 | * | |
178 | * Return: true if @vfsgid has a mapping in the filesystem, false if not. | |
179 | */ | |
4d7ca409 | 180 | static inline bool vfsgid_has_fsmapping(struct mnt_idmap *idmap, |
1e5267cd CB |
181 | struct user_namespace *fs_userns, |
182 | vfsgid_t vfsgid) | |
183 | { | |
4d7ca409 | 184 | return gid_valid(from_vfsgid(idmap, fs_userns, vfsgid)); |
1ac2a410 CB |
185 | } |
186 | ||
9c4f28dd CB |
187 | static inline bool vfsgid_has_mapping(struct user_namespace *userns, |
188 | vfsgid_t vfsgid) | |
189 | { | |
190 | return from_kgid(userns, AS_KGIDT(vfsgid)) != (gid_t)-1; | |
191 | } | |
192 | ||
c9fa2b07 CB |
193 | /** |
194 | * vfsgid_into_kgid - convert vfsgid into kgid | |
195 | * @vfsgid: the vfsgid to convert | |
196 | * | |
197 | * This can be used when a vfsgid is committed as a kgid. | |
198 | * | |
199 | * Return: a kgid with the value of @vfsgid | |
200 | */ | |
201 | static inline kgid_t vfsgid_into_kgid(vfsgid_t vfsgid) | |
202 | { | |
203 | return AS_KGIDT(vfsgid); | |
204 | } | |
205 | ||
a793d79e | 206 | /** |
c14329d3 CB |
207 | * mapped_fsuid - return caller's fsuid mapped according to an idmapping |
208 | * @idmap: the mount's idmapping | |
209188ce | 209 | * @fs_userns: the filesystem's idmapping |
a793d79e CB |
210 | * |
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 | |
215 | * user. | |
216 | * | |
c14329d3 | 217 | * Return: the caller's current fsuid mapped up according to @idmap. |
a793d79e | 218 | */ |
c14329d3 | 219 | static inline kuid_t mapped_fsuid(struct mnt_idmap *idmap, |
209188ce | 220 | struct user_namespace *fs_userns) |
a793d79e | 221 | { |
4d7ca409 | 222 | return from_vfsuid(idmap, fs_userns, VFSUIDT_INIT(current_fsuid())); |
a793d79e CB |
223 | } |
224 | ||
225 | /** | |
c14329d3 CB |
226 | * mapped_fsgid - return caller's fsgid mapped according to an idmapping |
227 | * @idmap: the mount's idmapping | |
209188ce | 228 | * @fs_userns: the filesystem's idmapping |
a793d79e CB |
229 | * |
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 | |
234 | * user. | |
235 | * | |
c14329d3 | 236 | * Return: the caller's current fsgid mapped up according to @idmap. |
a793d79e | 237 | */ |
c14329d3 | 238 | static inline kgid_t mapped_fsgid(struct mnt_idmap *idmap, |
209188ce | 239 | struct user_namespace *fs_userns) |
a793d79e | 240 | { |
4d7ca409 | 241 | return from_vfsgid(idmap, fs_userns, VFSGIDT_INIT(current_fsgid())); |
a793d79e CB |
242 | } |
243 | ||
3707d84c CB |
244 | bool check_fsmapping(const struct mnt_idmap *idmap, |
245 | const struct super_block *sb); | |
246 | ||
a793d79e | 247 | #endif /* _LINUX_MNT_IDMAPPING_H */ |