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
17 struct uid_gid_extent {
18 u32 first;
19 u32 lower_first;
20 u32 count;
21 };
22
23 struct 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
38 struct ucounts;
39
40 enum 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 UCOUNT_TIME_NAMESPACES,
49 #ifdef CONFIG_INOTIFY_USER
50 UCOUNT_INOTIFY_INSTANCES,
51 UCOUNT_INOTIFY_WATCHES,
52 #endif
53 UCOUNT_COUNTS,
54 };
55
56 struct user_namespace {
57 struct uid_gid_map uid_map;
58 struct uid_gid_map gid_map;
59 struct uid_gid_map projid_map;
60 atomic_t count;
61 struct user_namespace *parent;
62 int level;
63 kuid_t owner;
64 kgid_t group;
65 struct ns_common ns;
66 unsigned long flags;
67
68 #ifdef CONFIG_KEYS
69 /* List of joinable keyrings in this namespace. Modification access of
70 * these pointers is controlled by keyring_sem. Once
71 * user_keyring_register is set, it won't be changed, so it can be
72 * accessed directly with READ_ONCE().
73 */
74 struct list_head keyring_name_list;
75 struct key *user_keyring_register;
76 struct rw_semaphore keyring_sem;
77 #endif
78
79 /* Register of per-UID persistent keyrings for this namespace */
80 #ifdef CONFIG_PERSISTENT_KEYRINGS
81 struct key *persistent_keyring_register;
82 #endif
83 struct work_struct work;
84 #ifdef CONFIG_SYSCTL
85 struct ctl_table_set set;
86 struct ctl_table_header *sysctls;
87 #endif
88 struct ucounts *ucounts;
89 int ucount_max[UCOUNT_COUNTS];
90 } __randomize_layout;
91
92 struct ucounts {
93 struct hlist_node node;
94 struct user_namespace *ns;
95 kuid_t uid;
96 int count;
97 atomic_t ucount[UCOUNT_COUNTS];
98 };
99
100 extern struct user_namespace init_user_ns;
101
102 bool setup_userns_sysctls(struct user_namespace *ns);
103 void retire_userns_sysctls(struct user_namespace *ns);
104 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
105 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
106
107 #ifdef CONFIG_USER_NS
108
get_user_ns(struct user_namespace * ns)109 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
110 {
111 if (ns)
112 atomic_inc(&ns->count);
113 return ns;
114 }
115
116 extern int create_user_ns(struct cred *new);
117 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
118 extern void __put_user_ns(struct user_namespace *ns);
119
put_user_ns(struct user_namespace * ns)120 static inline void put_user_ns(struct user_namespace *ns)
121 {
122 if (ns && atomic_dec_and_test(&ns->count))
123 __put_user_ns(ns);
124 }
125
126 struct seq_operations;
127 extern const struct seq_operations proc_uid_seq_operations;
128 extern const struct seq_operations proc_gid_seq_operations;
129 extern const struct seq_operations proc_projid_seq_operations;
130 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
131 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
132 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
133 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
134 extern int proc_setgroups_show(struct seq_file *m, void *v);
135 extern bool userns_may_setgroups(const struct user_namespace *ns);
136 extern bool in_userns(const struct user_namespace *ancestor,
137 const struct user_namespace *child);
138 extern bool current_in_userns(const struct user_namespace *target_ns);
139 struct ns_common *ns_get_owner(struct ns_common *ns);
140 #else
141
get_user_ns(struct user_namespace * ns)142 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
143 {
144 return &init_user_ns;
145 }
146
create_user_ns(struct cred * new)147 static inline int create_user_ns(struct cred *new)
148 {
149 return -EINVAL;
150 }
151
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)152 static inline int unshare_userns(unsigned long unshare_flags,
153 struct cred **new_cred)
154 {
155 if (unshare_flags & CLONE_NEWUSER)
156 return -EINVAL;
157 return 0;
158 }
159
put_user_ns(struct user_namespace * ns)160 static inline void put_user_ns(struct user_namespace *ns)
161 {
162 }
163
userns_may_setgroups(const struct user_namespace * ns)164 static inline bool userns_may_setgroups(const struct user_namespace *ns)
165 {
166 return true;
167 }
168
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)169 static inline bool in_userns(const struct user_namespace *ancestor,
170 const struct user_namespace *child)
171 {
172 return true;
173 }
174
current_in_userns(const struct user_namespace * target_ns)175 static inline bool current_in_userns(const struct user_namespace *target_ns)
176 {
177 return true;
178 }
179
ns_get_owner(struct ns_common * ns)180 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
181 {
182 return ERR_PTR(-EPERM);
183 }
184 #endif
185
186 #endif /* _LINUX_USER_H */
187
