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 	/* 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 
81 struct 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 
89 extern struct user_namespace init_user_ns;
90 
91 bool setup_userns_sysctls(struct user_namespace *ns);
92 void retire_userns_sysctls(struct user_namespace *ns);
93 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
94 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
95 
96 #ifdef CONFIG_USER_NS
97 
get_user_ns(struct user_namespace * ns)98 static 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 
105 extern int create_user_ns(struct cred *new);
106 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
107 extern void __put_user_ns(struct user_namespace *ns);
108 
put_user_ns(struct user_namespace * ns)109 static 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 
115 struct seq_operations;
116 extern const struct seq_operations proc_uid_seq_operations;
117 extern const struct seq_operations proc_gid_seq_operations;
118 extern const struct seq_operations proc_projid_seq_operations;
119 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
120 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
121 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
122 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
123 extern int proc_setgroups_show(struct seq_file *m, void *v);
124 extern bool userns_may_setgroups(const struct user_namespace *ns);
125 extern bool in_userns(const struct user_namespace *ancestor,
126 		       const struct user_namespace *child);
127 extern bool current_in_userns(const struct user_namespace *target_ns);
128 struct ns_common *ns_get_owner(struct ns_common *ns);
129 #else
130 
get_user_ns(struct user_namespace * ns)131 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
132 {
133 	return &init_user_ns;
134 }
135 
create_user_ns(struct cred * new)136 static inline int create_user_ns(struct cred *new)
137 {
138 	return -EINVAL;
139 }
140 
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)141 static 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 
put_user_ns(struct user_namespace * ns)149 static inline void put_user_ns(struct user_namespace *ns)
150 {
151 }
152 
userns_may_setgroups(const struct user_namespace * ns)153 static inline bool userns_may_setgroups(const struct user_namespace *ns)
154 {
155 	return true;
156 }
157 
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)158 static inline bool in_userns(const struct user_namespace *ancestor,
159 			     const struct user_namespace *child)
160 {
161 	return true;
162 }
163 
current_in_userns(const struct user_namespace * target_ns)164 static inline bool current_in_userns(const struct user_namespace *target_ns)
165 {
166 	return true;
167 }
168 
ns_get_owner(struct ns_common * ns)169 static 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