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 union {
25 struct {
26 struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
27 u32 nr_extents;
28 };
29 struct {
30 struct uid_gid_extent *forward;
31 struct uid_gid_extent *reverse;
32 };
33 };
34 };
35
36 #define USERNS_SETGROUPS_ALLOWED 1UL
37
38 #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
39
40 struct ucounts;
41
42 enum ucount_type {
43 UCOUNT_USER_NAMESPACES,
44 UCOUNT_PID_NAMESPACES,
45 UCOUNT_UTS_NAMESPACES,
46 UCOUNT_IPC_NAMESPACES,
47 UCOUNT_NET_NAMESPACES,
48 UCOUNT_MNT_NAMESPACES,
49 UCOUNT_CGROUP_NAMESPACES,
50 UCOUNT_TIME_NAMESPACES,
51 #ifdef CONFIG_INOTIFY_USER
52 UCOUNT_INOTIFY_INSTANCES,
53 UCOUNT_INOTIFY_WATCHES,
54 #endif
55 #ifdef CONFIG_FANOTIFY
56 UCOUNT_FANOTIFY_GROUPS,
57 UCOUNT_FANOTIFY_MARKS,
58 #endif
59 UCOUNT_COUNTS,
60 };
61
62 enum rlimit_type {
63 UCOUNT_RLIMIT_NPROC,
64 UCOUNT_RLIMIT_MSGQUEUE,
65 UCOUNT_RLIMIT_SIGPENDING,
66 UCOUNT_RLIMIT_MEMLOCK,
67 UCOUNT_RLIMIT_COUNTS,
68 };
69
70 #if IS_ENABLED(CONFIG_BINFMT_MISC)
71 struct binfmt_misc;
72 #endif
73
74 struct user_namespace {
75 struct uid_gid_map uid_map;
76 struct uid_gid_map gid_map;
77 struct uid_gid_map projid_map;
78 struct user_namespace *parent;
79 int level;
80 kuid_t owner;
81 kgid_t group;
82 struct ns_common ns;
83 unsigned long flags;
84 /* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
85 * in its effective capability set at the child ns creation time. */
86 bool parent_could_setfcap;
87
88 #ifdef CONFIG_KEYS
89 /* List of joinable keyrings in this namespace. Modification access of
90 * these pointers is controlled by keyring_sem. Once
91 * user_keyring_register is set, it won't be changed, so it can be
92 * accessed directly with READ_ONCE().
93 */
94 struct list_head keyring_name_list;
95 struct key *user_keyring_register;
96 struct rw_semaphore keyring_sem;
97 #endif
98
99 /* Register of per-UID persistent keyrings for this namespace */
100 #ifdef CONFIG_PERSISTENT_KEYRINGS
101 struct key *persistent_keyring_register;
102 #endif
103 struct work_struct work;
104 #ifdef CONFIG_SYSCTL
105 struct ctl_table_set set;
106 struct ctl_table_header *sysctls;
107 #endif
108 struct ucounts *ucounts;
109 long ucount_max[UCOUNT_COUNTS];
110 long rlimit_max[UCOUNT_RLIMIT_COUNTS];
111
112 #if IS_ENABLED(CONFIG_BINFMT_MISC)
113 struct binfmt_misc *binfmt_misc;
114 #endif
115 } __randomize_layout;
116
117 struct ucounts {
118 struct hlist_node node;
119 struct user_namespace *ns;
120 kuid_t uid;
121 atomic_t count;
122 atomic_long_t ucount[UCOUNT_COUNTS];
123 atomic_long_t rlimit[UCOUNT_RLIMIT_COUNTS];
124 };
125
126 extern struct user_namespace init_user_ns;
127 extern struct ucounts init_ucounts;
128
129 bool setup_userns_sysctls(struct user_namespace *ns);
130 void retire_userns_sysctls(struct user_namespace *ns);
131 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
132 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
133 struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
134 struct ucounts * __must_check get_ucounts(struct ucounts *ucounts);
135 void put_ucounts(struct ucounts *ucounts);
136
get_rlimit_value(struct ucounts * ucounts,enum rlimit_type type)137 static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type type)
138 {
139 return atomic_long_read(&ucounts->rlimit[type]);
140 }
141
142 long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
143 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
144 long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type);
145 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type);
146 bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max);
147
get_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type)148 static inline long get_userns_rlimit_max(struct user_namespace *ns, enum rlimit_type type)
149 {
150 return READ_ONCE(ns->rlimit_max[type]);
151 }
152
set_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type,unsigned long max)153 static inline void set_userns_rlimit_max(struct user_namespace *ns,
154 enum rlimit_type type, unsigned long max)
155 {
156 ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX;
157 }
158
159 #ifdef CONFIG_USER_NS
160
get_user_ns(struct user_namespace * ns)161 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
162 {
163 if (ns)
164 refcount_inc(&ns->ns.count);
165 return ns;
166 }
167
168 extern int create_user_ns(struct cred *new);
169 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
170 extern void __put_user_ns(struct user_namespace *ns);
171
put_user_ns(struct user_namespace * ns)172 static inline void put_user_ns(struct user_namespace *ns)
173 {
174 if (ns && refcount_dec_and_test(&ns->ns.count))
175 __put_user_ns(ns);
176 }
177
178 struct seq_operations;
179 extern const struct seq_operations proc_uid_seq_operations;
180 extern const struct seq_operations proc_gid_seq_operations;
181 extern const struct seq_operations proc_projid_seq_operations;
182 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
183 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
184 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
185 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
186 extern int proc_setgroups_show(struct seq_file *m, void *v);
187 extern bool userns_may_setgroups(const struct user_namespace *ns);
188 extern bool in_userns(const struct user_namespace *ancestor,
189 const struct user_namespace *child);
190 extern bool current_in_userns(const struct user_namespace *target_ns);
191 struct ns_common *ns_get_owner(struct ns_common *ns);
192 #else
193
get_user_ns(struct user_namespace * ns)194 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
195 {
196 return &init_user_ns;
197 }
198
create_user_ns(struct cred * new)199 static inline int create_user_ns(struct cred *new)
200 {
201 return -EINVAL;
202 }
203
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)204 static inline int unshare_userns(unsigned long unshare_flags,
205 struct cred **new_cred)
206 {
207 if (unshare_flags & CLONE_NEWUSER)
208 return -EINVAL;
209 return 0;
210 }
211
put_user_ns(struct user_namespace * ns)212 static inline void put_user_ns(struct user_namespace *ns)
213 {
214 }
215
userns_may_setgroups(const struct user_namespace * ns)216 static inline bool userns_may_setgroups(const struct user_namespace *ns)
217 {
218 return true;
219 }
220
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)221 static inline bool in_userns(const struct user_namespace *ancestor,
222 const struct user_namespace *child)
223 {
224 return true;
225 }
226
current_in_userns(const struct user_namespace * target_ns)227 static inline bool current_in_userns(const struct user_namespace *target_ns)
228 {
229 return true;
230 }
231
ns_get_owner(struct ns_common * ns)232 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
233 {
234 return ERR_PTR(-EPERM);
235 }
236 #endif
237
238 #endif /* _LINUX_USER_H */
239