1#ifndef _LINUX_USER_NAMESPACE_H
2#define _LINUX_USER_NAMESPACE_H
3
4#include <linux/kref.h>
5#include <linux/nsproxy.h>
6#include <linux/ns_common.h>
7#include <linux/sched.h>
8#include <linux/err.h>
9
10#define UID_GID_MAP_MAX_EXTENTS 5
11
12struct uid_gid_map {	/* 64 bytes -- 1 cache line */
13	u32 nr_extents;
14	struct uid_gid_extent {
15		u32 first;
16		u32 lower_first;
17		u32 count;
18	} extent[UID_GID_MAP_MAX_EXTENTS];
19};
20
21#define USERNS_SETGROUPS_ALLOWED 1UL
22
23#define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
24
25struct user_namespace {
26	struct uid_gid_map	uid_map;
27	struct uid_gid_map	gid_map;
28	struct uid_gid_map	projid_map;
29	atomic_t		count;
30	struct user_namespace	*parent;
31	int			level;
32	kuid_t			owner;
33	kgid_t			group;
34	struct ns_common	ns;
35	unsigned long		flags;
36
37	/* Register of per-UID persistent keyrings for this namespace */
38#ifdef CONFIG_PERSISTENT_KEYRINGS
39	struct key		*persistent_keyring_register;
40	struct rw_semaphore	persistent_keyring_register_sem;
41#endif
42};
43
44extern struct user_namespace init_user_ns;
45
46#ifdef CONFIG_USER_NS
47
48static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
49{
50	if (ns)
51		atomic_inc(&ns->count);
52	return ns;
53}
54
55extern int create_user_ns(struct cred *new);
56extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
57extern void free_user_ns(struct user_namespace *ns);
58
59static inline void put_user_ns(struct user_namespace *ns)
60{
61	if (ns && atomic_dec_and_test(&ns->count))
62		free_user_ns(ns);
63}
64
65struct seq_operations;
66extern const struct seq_operations proc_uid_seq_operations;
67extern const struct seq_operations proc_gid_seq_operations;
68extern const struct seq_operations proc_projid_seq_operations;
69extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
70extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
71extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
72extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
73extern int proc_setgroups_show(struct seq_file *m, void *v);
74extern bool userns_may_setgroups(const struct user_namespace *ns);
75#else
76
77static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
78{
79	return &init_user_ns;
80}
81
82static inline int create_user_ns(struct cred *new)
83{
84	return -EINVAL;
85}
86
87static inline int unshare_userns(unsigned long unshare_flags,
88				 struct cred **new_cred)
89{
90	if (unshare_flags & CLONE_NEWUSER)
91		return -EINVAL;
92	return 0;
93}
94
95static inline void put_user_ns(struct user_namespace *ns)
96{
97}
98
99static inline bool userns_may_setgroups(const struct user_namespace *ns)
100{
101	return true;
102}
103#endif
104
105#endif /* _LINUX_USER_H */
106