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uidgid.h
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1 #ifndef _LINUX_UIDGID_H
2 #define _LINUX_UIDGID_H
3 
4 /*
5  * A set of types for the internal kernel types representing uids and gids.
6  *
7  * The types defined in this header allow distinguishing which uids and gids in
8  * the kernel are values used by userspace and which uid and gid values are
9  * the internal kernel values. With the addition of user namespaces the values
10  * can be different. Using the type system makes it possible for the compiler
11  * to detect when we overlook these differences.
12  *
13  */
14 #include <linux/types.h>
15 #include <linux/highuid.h>
16 
17 struct user_namespace;
18 extern struct user_namespace init_user_ns;
19 
20 #ifdef CONFIG_UIDGID_STRICT_TYPE_CHECKS
21 
22 typedef struct {
23  uid_t val;
24 } kuid_t;
25 
26 
27 typedef struct {
28  gid_t val;
29 } kgid_t;
30 
31 #define KUIDT_INIT(value) (kuid_t){ value }
32 #define KGIDT_INIT(value) (kgid_t){ value }
33 
34 static inline uid_t __kuid_val(kuid_t uid)
35 {
36  return uid.val;
37 }
38 
39 static inline gid_t __kgid_val(kgid_t gid)
40 {
41  return gid.val;
42 }
43 
44 #else
45 
46 typedef uid_t kuid_t;
47 typedef gid_t kgid_t;
48 
49 static inline uid_t __kuid_val(kuid_t uid)
50 {
51  return uid;
52 }
53 
54 static inline gid_t __kgid_val(kgid_t gid)
55 {
56  return gid;
57 }
58 
59 #define KUIDT_INIT(value) ((kuid_t) value )
60 #define KGIDT_INIT(value) ((kgid_t) value )
61 
62 #endif
63 
64 #define GLOBAL_ROOT_UID KUIDT_INIT(0)
65 #define GLOBAL_ROOT_GID KGIDT_INIT(0)
66 
67 #define INVALID_UID KUIDT_INIT(-1)
68 #define INVALID_GID KGIDT_INIT(-1)
69 
70 static inline bool uid_eq(kuid_t left, kuid_t right)
71 {
72  return __kuid_val(left) == __kuid_val(right);
73 }
74 
75 static inline bool gid_eq(kgid_t left, kgid_t right)
76 {
77  return __kgid_val(left) == __kgid_val(right);
78 }
79 
80 static inline bool uid_gt(kuid_t left, kuid_t right)
81 {
82  return __kuid_val(left) > __kuid_val(right);
83 }
84 
85 static inline bool gid_gt(kgid_t left, kgid_t right)
86 {
87  return __kgid_val(left) > __kgid_val(right);
88 }
89 
90 static inline bool uid_gte(kuid_t left, kuid_t right)
91 {
92  return __kuid_val(left) >= __kuid_val(right);
93 }
94 
95 static inline bool gid_gte(kgid_t left, kgid_t right)
96 {
97  return __kgid_val(left) >= __kgid_val(right);
98 }
99 
100 static inline bool uid_lt(kuid_t left, kuid_t right)
101 {
102  return __kuid_val(left) < __kuid_val(right);
103 }
104 
105 static inline bool gid_lt(kgid_t left, kgid_t right)
106 {
107  return __kgid_val(left) < __kgid_val(right);
108 }
109 
110 static inline bool uid_lte(kuid_t left, kuid_t right)
111 {
112  return __kuid_val(left) <= __kuid_val(right);
113 }
114 
115 static inline bool gid_lte(kgid_t left, kgid_t right)
116 {
117  return __kgid_val(left) <= __kgid_val(right);
118 }
119 
120 static inline bool uid_valid(kuid_t uid)
121 {
122  return !uid_eq(uid, INVALID_UID);
123 }
124 
125 static inline bool gid_valid(kgid_t gid)
126 {
127  return !gid_eq(gid, INVALID_GID);
128 }
129 
130 #ifdef CONFIG_USER_NS
131 
132 extern kuid_t make_kuid(struct user_namespace *from, uid_t uid);
133 extern kgid_t make_kgid(struct user_namespace *from, gid_t gid);
134 
135 extern uid_t from_kuid(struct user_namespace *to, kuid_t uid);
136 extern gid_t from_kgid(struct user_namespace *to, kgid_t gid);
137 extern uid_t from_kuid_munged(struct user_namespace *to, kuid_t uid);
138 extern gid_t from_kgid_munged(struct user_namespace *to, kgid_t gid);
139 
140 static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
141 {
142  return from_kuid(ns, uid) != (uid_t) -1;
143 }
144 
145 static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
146 {
147  return from_kgid(ns, gid) != (gid_t) -1;
148 }
149 
150 #else
151 
152 static inline kuid_t make_kuid(struct user_namespace *from, uid_t uid)
153 {
154  return KUIDT_INIT(uid);
155 }
156 
157 static inline kgid_t make_kgid(struct user_namespace *from, gid_t gid)
158 {
159  return KGIDT_INIT(gid);
160 }
161 
162 static inline uid_t from_kuid(struct user_namespace *to, kuid_t kuid)
163 {
164  return __kuid_val(kuid);
165 }
166 
167 static inline gid_t from_kgid(struct user_namespace *to, kgid_t kgid)
168 {
169  return __kgid_val(kgid);
170 }
171 
172 static inline uid_t from_kuid_munged(struct user_namespace *to, kuid_t kuid)
173 {
174  uid_t uid = from_kuid(to, kuid);
175  if (uid == (uid_t)-1)
176  uid = overflowuid;
177  return uid;
178 }
179 
180 static inline gid_t from_kgid_munged(struct user_namespace *to, kgid_t kgid)
181 {
182  gid_t gid = from_kgid(to, kgid);
183  if (gid == (gid_t)-1)
184  gid = overflowgid;
185  return gid;
186 }
187 
188 static inline bool kuid_has_mapping(struct user_namespace *ns, kuid_t uid)
189 {
190  return true;
191 }
192 
193 static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid)
194 {
195  return true;
196 }
197 
198 #endif /* CONFIG_USER_NS */
199 
200 #endif /* _LINUX_UIDGID_H */