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