1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_PROJID_H
3 #define _LINUX_PROJID_H
4
5 /*
6 * A set of types for the internal kernel types representing project ids.
7 *
8 * The types defined in this header allow distinguishing which project ids in
9 * the kernel are values used by userspace and which project id values are
10 * the internal kernel values. With the addition of user namespaces the values
11 * can be different. Using the type system makes it possible for the compiler
12 * to detect when we overlook these differences.
13 *
14 */
15 #include <linux/types.h>
16
17 struct user_namespace;
18 extern struct user_namespace init_user_ns;
19
20 typedef __kernel_uid32_t projid_t;
21
22 typedef struct {
23 projid_t val;
24 } kprojid_t;
25
26 static inline projid_t __kprojid_val(kprojid_t projid)
27 {
28 return projid.val;
29 }
30
31 #define KPROJIDT_INIT(value) (kprojid_t){ value }
32
33 #define INVALID_PROJID KPROJIDT_INIT(-1)
34 #define OVERFLOW_PROJID 65534
35
36 static inline bool projid_eq(kprojid_t left, kprojid_t right)
37 {
38 return __kprojid_val(left) == __kprojid_val(right);
39 }
40
41 static inline bool projid_lt(kprojid_t left, kprojid_t right)
42 {
43 return __kprojid_val(left) < __kprojid_val(right);
44 }
45
46 static inline bool projid_valid(kprojid_t projid)
47 {
48 return !projid_eq(projid, INVALID_PROJID);
49 }
50
51 #ifdef CONFIG_USER_NS
52
53 extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
54
55 extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
56 extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
57
58 static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
59 {
60 return from_kprojid(ns, projid) != (projid_t)-1;
61 }
62
63 #else
64
65 static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
66 {
67 return KPROJIDT_INIT(projid);
68 }
69
70 static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
71 {
72 return __kprojid_val(kprojid);
73 }
74
75 static inline projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t kprojid)
76 {
77 projid_t projid = from_kprojid(to, kprojid);
78 if (projid == (projid_t)-1)
79 projid = OVERFLOW_PROJID;
80 return projid;
81 }
82
83 static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
84 {
85 return true;
86 }
87
88 #endif /* CONFIG_USER_NS */
89
90 #endif /* _LINUX_PROJID_H */
91
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