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_COUNTS,
58 };
59
60 enum rlimit_type {
61 UCOUNT_RLIMIT_NPROC,
62 UCOUNT_RLIMIT_MSGQUEUE,
63 UCOUNT_RLIMIT_SIGPENDING,
64 UCOUNT_RLIMIT_MEMLOCK,
65 UCOUNT_RLIMIT_COUNTS,
66 };
67
68 struct user_namespace {
69 struct uid_gid_map uid_map;
70 struct uid_gid_map gid_map;
71 struct uid_gid_map projid_map;
72 struct user_namespace *parent;
73 int level;
74 kuid_t owner;
75 kgid_t group;
76 struct ns_common ns;
77 unsigned long flags;
78 /* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
79 * in its effective capability set at the child ns creation time. */
80 bool parent_could_setfcap;
81
82 #ifdef CONFIG_KEYS
83 /* List of joinable keyrings in this namespace. Modification access of
84 * these pointers is controlled by keyring_sem. Once
85 * user_keyring_register is set, it won't be changed, so it can be
86 * accessed directly with READ_ONCE().
87 */
88 struct list_head keyring_name_list;
89 struct key *user_keyring_register;
90 struct rw_semaphore keyring_sem;
91 #endif
92
93 /* Register of per-UID persistent keyrings for this namespace */
94 #ifdef CONFIG_PERSISTENT_KEYRINGS
95 struct key *persistent_keyring_register;
96 #endif
97 struct work_struct work;
98 #ifdef CONFIG_SYSCTL
99 struct ctl_table_set set;
100 struct ctl_table_header *sysctls;
101 #endif
102 struct ucounts *ucounts;
103 long ucount_max[UCOUNT_COUNTS];
104 long rlimit_max[UCOUNT_RLIMIT_COUNTS];
105 } __randomize_layout;
106
107 struct ucounts {
108 struct hlist_node node;
109 struct user_namespace *ns;
110 kuid_t uid;
111 atomic_t count;
112 atomic_long_t ucount[UCOUNT_COUNTS];
113 atomic_long_t rlimit[UCOUNT_RLIMIT_COUNTS];
114 };
115
116 extern struct user_namespace init_user_ns;
117 extern struct ucounts init_ucounts;
118
119 bool setup_userns_sysctls(struct user_namespace *ns);
120 void retire_userns_sysctls(struct user_namespace *ns);
121 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
122 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
123 struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
124 struct ucounts * __must_check get_ucounts(struct ucounts *ucounts);
125 void put_ucounts(struct ucounts *ucounts);
126
get_rlimit_value(struct ucounts * ucounts,enum rlimit_type type)127 static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type type)
128 {
129 return atomic_long_read(&ucounts->rlimit[type]);
130 }
131
132 long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
133 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
134 long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type);
135 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type);
136 bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max);
137
get_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type)138 static inline long get_userns_rlimit_max(struct user_namespace *ns, enum rlimit_type type)
139 {
140 return READ_ONCE(ns->rlimit_max[type]);
141 }
142
set_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type,unsigned long max)143 static inline void set_userns_rlimit_max(struct user_namespace *ns,
144 enum rlimit_type type, unsigned long max)
145 {
146 ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX;
147 }
148
149 #ifdef CONFIG_USER_NS
150
get_user_ns(struct user_namespace * ns)151 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
152 {
153 if (ns)
154 refcount_inc(&ns->ns.count);
155 return ns;
156 }
157
158 extern int create_user_ns(struct cred *new);
159 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
160 extern void __put_user_ns(struct user_namespace *ns);
161
put_user_ns(struct user_namespace * ns)162 static inline void put_user_ns(struct user_namespace *ns)
163 {
164 if (ns && refcount_dec_and_test(&ns->ns.count))
165 __put_user_ns(ns);
166 }
167
168 struct seq_operations;
169 extern const struct seq_operations proc_uid_seq_operations;
170 extern const struct seq_operations proc_gid_seq_operations;
171 extern const struct seq_operations proc_projid_seq_operations;
172 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
173 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
174 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
175 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
176 extern int proc_setgroups_show(struct seq_file *m, void *v);
177 extern bool userns_may_setgroups(const struct user_namespace *ns);
178 extern bool in_userns(const struct user_namespace *ancestor,
179 const struct user_namespace *child);
180 extern bool current_in_userns(const struct user_namespace *target_ns);
181 struct ns_common *ns_get_owner(struct ns_common *ns);
182 #else
183
get_user_ns(struct user_namespace * ns)184 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
185 {
186 return &init_user_ns;
187 }
188
create_user_ns(struct cred * new)189 static inline int create_user_ns(struct cred *new)
190 {
191 return -EINVAL;
192 }
193
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)194 static inline int unshare_userns(unsigned long unshare_flags,
195 struct cred **new_cred)
196 {
197 if (unshare_flags & CLONE_NEWUSER)
198 return -EINVAL;
199 return 0;
200 }
201
put_user_ns(struct user_namespace * ns)202 static inline void put_user_ns(struct user_namespace *ns)
203 {
204 }
205
userns_may_setgroups(const struct user_namespace * ns)206 static inline bool userns_may_setgroups(const struct user_namespace *ns)
207 {
208 return true;
209 }
210
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)211 static inline bool in_userns(const struct user_namespace *ancestor,
212 const struct user_namespace *child)
213 {
214 return true;
215 }
216
current_in_userns(const struct user_namespace * target_ns)217 static inline bool current_in_userns(const struct user_namespace *target_ns)
218 {
219 return true;
220 }
221
ns_get_owner(struct ns_common * ns)222 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
223 {
224 return ERR_PTR(-EPERM);
225 }
226 #endif
227
228 #endif /* _LINUX_USER_H */
229