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