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 bool override_rlimit);
136 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type);
137 bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max);
138
get_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type)139 static inline long get_userns_rlimit_max(struct user_namespace *ns, enum rlimit_type type)
140 {
141 return READ_ONCE(ns->rlimit_max[type]);
142 }
143
set_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type,unsigned long max)144 static inline void set_userns_rlimit_max(struct user_namespace *ns,
145 enum rlimit_type type, unsigned long max)
146 {
147 ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX;
148 }
149
150 #ifdef CONFIG_USER_NS
151
get_user_ns(struct user_namespace * ns)152 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
153 {
154 if (ns)
155 refcount_inc(&ns->ns.count);
156 return ns;
157 }
158
159 extern int create_user_ns(struct cred *new);
160 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
161 extern void __put_user_ns(struct user_namespace *ns);
162
put_user_ns(struct user_namespace * ns)163 static inline void put_user_ns(struct user_namespace *ns)
164 {
165 if (ns && refcount_dec_and_test(&ns->ns.count))
166 __put_user_ns(ns);
167 }
168
169 struct seq_operations;
170 extern const struct seq_operations proc_uid_seq_operations;
171 extern const struct seq_operations proc_gid_seq_operations;
172 extern const struct seq_operations proc_projid_seq_operations;
173 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
174 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
175 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
176 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
177 extern int proc_setgroups_show(struct seq_file *m, void *v);
178 extern bool userns_may_setgroups(const struct user_namespace *ns);
179 extern bool in_userns(const struct user_namespace *ancestor,
180 const struct user_namespace *child);
181 extern bool current_in_userns(const struct user_namespace *target_ns);
182 struct ns_common *ns_get_owner(struct ns_common *ns);
183 #else
184
get_user_ns(struct user_namespace * ns)185 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
186 {
187 return &init_user_ns;
188 }
189
create_user_ns(struct cred * new)190 static inline int create_user_ns(struct cred *new)
191 {
192 return -EINVAL;
193 }
194
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)195 static inline int unshare_userns(unsigned long unshare_flags,
196 struct cred **new_cred)
197 {
198 if (unshare_flags & CLONE_NEWUSER)
199 return -EINVAL;
200 return 0;
201 }
202
put_user_ns(struct user_namespace * ns)203 static inline void put_user_ns(struct user_namespace *ns)
204 {
205 }
206
userns_may_setgroups(const struct user_namespace * ns)207 static inline bool userns_may_setgroups(const struct user_namespace *ns)
208 {
209 return true;
210 }
211
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)212 static inline bool in_userns(const struct user_namespace *ancestor,
213 const struct user_namespace *child)
214 {
215 return true;
216 }
217
current_in_userns(const struct user_namespace * target_ns)218 static inline bool current_in_userns(const struct user_namespace *target_ns)
219 {
220 return true;
221 }
222
ns_get_owner(struct ns_common * ns)223 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
224 {
225 return ERR_PTR(-EPERM);
226 }
227 #endif
228
229 #endif /* _LINUX_USER_H */
230