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
17struct user_namespace;
18extern struct user_namespace init_user_ns;
19
20typedef __kernel_uid32_t projid_t;
21
22typedef struct {
23 projid_t val;
24} kprojid_t;
25
26static 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
36static inline bool projid_eq(kprojid_t left, kprojid_t right)
37{
38 return __kprojid_val(projid: left) == __kprojid_val(projid: right);
39}
40
41static inline bool projid_lt(kprojid_t left, kprojid_t right)
42{
43 return __kprojid_val(projid: left) < __kprojid_val(projid: right);
44}
45
46static inline bool projid_valid(kprojid_t projid)
47{
48 return !projid_eq(left: projid, INVALID_PROJID);
49}
50
51#ifdef CONFIG_USER_NS
52
53extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
54
55extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
56extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
57
58static 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
65static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
66{
67 return KPROJIDT_INIT(projid);
68}
69
70static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
71{
72 return __kprojid_val(projid: kprojid);
73}
74
75static 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
83static 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