1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_USER_NAMESPACE_H
3#define _LINUX_USER_NAMESPACE_H
4
5#include <linux/kref.h>
6#include <linux/nsproxy.h>
7#include <linux/ns_common.h>
8#include <linux/sched.h>
9#include <linux/workqueue.h>
10#include <linux/rwsem.h>
11#include <linux/sysctl.h>
12#include <linux/err.h>
13
14#define UID_GID_MAP_MAX_BASE_EXTENTS 5
15#define UID_GID_MAP_MAX_EXTENTS 340
16
17struct uid_gid_extent {
18 u32 first;
19 u32 lower_first;
20 u32 count;
21};
22
23struct uid_gid_map { /* 64 bytes -- 1 cache line */
24 u32 nr_extents;
25 union {
26 struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
27 struct {
28 struct uid_gid_extent *forward;
29 struct uid_gid_extent *reverse;
30 };
31 };
32};
33
34#define USERNS_SETGROUPS_ALLOWED 1UL
35
36#define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
37
38struct ucounts;
39
40enum ucount_type {
41 UCOUNT_USER_NAMESPACES,
42 UCOUNT_PID_NAMESPACES,
43 UCOUNT_UTS_NAMESPACES,
44 UCOUNT_IPC_NAMESPACES,
45 UCOUNT_NET_NAMESPACES,
46 UCOUNT_MNT_NAMESPACES,
47 UCOUNT_CGROUP_NAMESPACES,
48#ifdef CONFIG_INOTIFY_USER
49 UCOUNT_INOTIFY_INSTANCES,
50 UCOUNT_INOTIFY_WATCHES,
51#endif
52 UCOUNT_COUNTS,
53};
54
55struct user_namespace {
56 struct uid_gid_map uid_map;
57 struct uid_gid_map gid_map;
58 struct uid_gid_map projid_map;
59 atomic_t count;
60 struct user_namespace *parent;
61 int level;
62 kuid_t owner;
63 kgid_t group;
64 struct ns_common ns;
65 unsigned long flags;
66
67 /* Register of per-UID persistent keyrings for this namespace */
68#ifdef CONFIG_PERSISTENT_KEYRINGS
69 struct key *persistent_keyring_register;
70 struct rw_semaphore persistent_keyring_register_sem;
71#endif
72 struct work_struct work;
73#ifdef CONFIG_SYSCTL
74 struct ctl_table_set set;
75 struct ctl_table_header *sysctls;
76#endif
77 struct ucounts *ucounts;
78 int ucount_max[UCOUNT_COUNTS];
79} __randomize_layout;
80
81struct ucounts {
82 struct hlist_node node;
83 struct user_namespace *ns;
84 kuid_t uid;
85 int count;
86 atomic_t ucount[UCOUNT_COUNTS];
87};
88
89extern struct user_namespace init_user_ns;
90
91bool setup_userns_sysctls(struct user_namespace *ns);
92void retire_userns_sysctls(struct user_namespace *ns);
93struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
94void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
95
96#ifdef CONFIG_USER_NS
97
98static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
99{
100 if (ns)
101 atomic_inc(&ns->count);
102 return ns;
103}
104
105extern int create_user_ns(struct cred *new);
106extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
107extern void __put_user_ns(struct user_namespace *ns);
108
109static inline void put_user_ns(struct user_namespace *ns)
110{
111 if (ns && atomic_dec_and_test(&ns->count))
112 __put_user_ns(ns);
113}
114
115struct seq_operations;
116extern const struct seq_operations proc_uid_seq_operations;
117extern const struct seq_operations proc_gid_seq_operations;
118extern const struct seq_operations proc_projid_seq_operations;
119extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
120extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
121extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
122extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
123extern int proc_setgroups_show(struct seq_file *m, void *v);
124extern bool userns_may_setgroups(const struct user_namespace *ns);
125extern bool in_userns(const struct user_namespace *ancestor,
126 const struct user_namespace *child);
127extern bool current_in_userns(const struct user_namespace *target_ns);
128struct ns_common *ns_get_owner(struct ns_common *ns);
129#else
130
131static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
132{
133 return &init_user_ns;
134}
135
136static inline int create_user_ns(struct cred *new)
137{
138 return -EINVAL;
139}
140
141static inline int unshare_userns(unsigned long unshare_flags,
142 struct cred **new_cred)
143{
144 if (unshare_flags & CLONE_NEWUSER)
145 return -EINVAL;
146 return 0;
147}
148
149static inline void put_user_ns(struct user_namespace *ns)
150{
151}
152
153static inline bool userns_may_setgroups(const struct user_namespace *ns)
154{
155 return true;
156}
157
158static inline bool in_userns(const struct user_namespace *ancestor,
159 const struct user_namespace *child)
160{
161 return true;
162}
163
164static inline bool current_in_userns(const struct user_namespace *target_ns)
165{
166 return true;
167}
168
169static inline struct ns_common *ns_get_owner(struct ns_common *ns)
170{
171 return ERR_PTR(-EPERM);
172}
173#endif
174
175#endif /* _LINUX_USER_H */
176