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 #ifdef CONFIG_FANOTIFY
54 UCOUNT_FANOTIFY_GROUPS,
55 UCOUNT_FANOTIFY_MARKS,
56 #endif
57 UCOUNT_RLIMIT_NPROC,
58 UCOUNT_RLIMIT_MSGQUEUE,
59 UCOUNT_RLIMIT_SIGPENDING,
60 UCOUNT_RLIMIT_MEMLOCK,
61 UCOUNT_COUNTS,
62 };
63
64 #define MAX_PER_NAMESPACE_UCOUNTS UCOUNT_RLIMIT_NPROC
65
66 struct user_namespace {
67 struct uid_gid_map uid_map;
68 struct uid_gid_map gid_map;
69 struct uid_gid_map projid_map;
70 struct user_namespace *parent;
71 int level;
72 kuid_t owner;
73 kgid_t group;
74 struct ns_common ns;
75 unsigned long flags;
76 /* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
77 * in its effective capability set at the child ns creation time. */
78 bool parent_could_setfcap;
79
80 #ifdef CONFIG_KEYS
81 /* List of joinable keyrings in this namespace. Modification access of
82 * these pointers is controlled by keyring_sem. Once
83 * user_keyring_register is set, it won't be changed, so it can be
84 * accessed directly with READ_ONCE().
85 */
86 struct list_head keyring_name_list;
87 struct key *user_keyring_register;
88 struct rw_semaphore keyring_sem;
89 #endif
90
91 /* Register of per-UID persistent keyrings for this namespace */
92 #ifdef CONFIG_PERSISTENT_KEYRINGS
93 struct key *persistent_keyring_register;
94 #endif
95 struct work_struct work;
96 #ifdef CONFIG_SYSCTL
97 struct ctl_table_set set;
98 struct ctl_table_header *sysctls;
99 #endif
100 struct ucounts *ucounts;
101 long ucount_max[UCOUNT_COUNTS];
102 } __randomize_layout;
103
104 struct ucounts {
105 struct hlist_node node;
106 struct user_namespace *ns;
107 kuid_t uid;
108 atomic_t count;
109 atomic_long_t ucount[UCOUNT_COUNTS];
110 };
111
112 extern struct user_namespace init_user_ns;
113 extern struct ucounts init_ucounts;
114
115 bool setup_userns_sysctls(struct user_namespace *ns);
116 void retire_userns_sysctls(struct user_namespace *ns);
117 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
118 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
119 struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
120 struct ucounts * __must_check get_ucounts(struct ucounts *ucounts);
121 void put_ucounts(struct ucounts *ucounts);
122
get_ucounts_value(struct ucounts * ucounts,enum ucount_type type)123 static inline long get_ucounts_value(struct ucounts *ucounts, enum ucount_type type)
124 {
125 return atomic_long_read(&ucounts->ucount[type]);
126 }
127
128 long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v);
129 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v);
130 long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum ucount_type type);
131 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum ucount_type type);
132 bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long max);
133
set_rlimit_ucount_max(struct user_namespace * ns,enum ucount_type type,unsigned long max)134 static inline void set_rlimit_ucount_max(struct user_namespace *ns,
135 enum ucount_type type, unsigned long max)
136 {
137 ns->ucount_max[type] = max <= LONG_MAX ? max : LONG_MAX;
138 }
139
140 #ifdef CONFIG_USER_NS
141
get_user_ns(struct user_namespace * ns)142 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
143 {
144 if (ns)
145 refcount_inc(&ns->ns.count);
146 return ns;
147 }
148
149 extern int create_user_ns(struct cred *new);
150 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
151 extern void __put_user_ns(struct user_namespace *ns);
152
put_user_ns(struct user_namespace * ns)153 static inline void put_user_ns(struct user_namespace *ns)
154 {
155 if (ns && refcount_dec_and_test(&ns->ns.count))
156 __put_user_ns(ns);
157 }
158
159 struct seq_operations;
160 extern const struct seq_operations proc_uid_seq_operations;
161 extern const struct seq_operations proc_gid_seq_operations;
162 extern const struct seq_operations proc_projid_seq_operations;
163 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
164 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
165 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
166 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
167 extern int proc_setgroups_show(struct seq_file *m, void *v);
168 extern bool userns_may_setgroups(const struct user_namespace *ns);
169 extern bool in_userns(const struct user_namespace *ancestor,
170 const struct user_namespace *child);
171 extern bool current_in_userns(const struct user_namespace *target_ns);
172 struct ns_common *ns_get_owner(struct ns_common *ns);
173 #else
174
get_user_ns(struct user_namespace * ns)175 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
176 {
177 return &init_user_ns;
178 }
179
create_user_ns(struct cred * new)180 static inline int create_user_ns(struct cred *new)
181 {
182 return -EINVAL;
183 }
184
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)185 static inline int unshare_userns(unsigned long unshare_flags,
186 struct cred **new_cred)
187 {
188 if (unshare_flags & CLONE_NEWUSER)
189 return -EINVAL;
190 return 0;
191 }
192
put_user_ns(struct user_namespace * ns)193 static inline void put_user_ns(struct user_namespace *ns)
194 {
195 }
196
userns_may_setgroups(const struct user_namespace * ns)197 static inline bool userns_may_setgroups(const struct user_namespace *ns)
198 {
199 return true;
200 }
201
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)202 static inline bool in_userns(const struct user_namespace *ancestor,
203 const struct user_namespace *child)
204 {
205 return true;
206 }
207
current_in_userns(const struct user_namespace * target_ns)208 static inline bool current_in_userns(const struct user_namespace *target_ns)
209 {
210 return true;
211 }
212
ns_get_owner(struct ns_common * ns)213 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
214 {
215 return ERR_PTR(-EPERM);
216 }
217 #endif
218
219 #endif /* _LINUX_USER_H */
220