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 #include <linux/android_kabi.h>
14
15 #define UID_GID_MAP_MAX_BASE_EXTENTS 5
16 #define UID_GID_MAP_MAX_EXTENTS 340
17
18 struct uid_gid_extent {
19 u32 first;
20 u32 lower_first;
21 u32 count;
22 };
23
24 struct uid_gid_map { /* 64 bytes -- 1 cache line */
25 u32 nr_extents;
26 union {
27 struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
28 struct {
29 struct uid_gid_extent *forward;
30 struct uid_gid_extent *reverse;
31 };
32 };
33 };
34
35 #define USERNS_SETGROUPS_ALLOWED 1UL
36
37 #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
38
39 struct ucounts;
40
41 enum ucount_type {
42 UCOUNT_USER_NAMESPACES,
43 UCOUNT_PID_NAMESPACES,
44 UCOUNT_UTS_NAMESPACES,
45 UCOUNT_IPC_NAMESPACES,
46 UCOUNT_NET_NAMESPACES,
47 UCOUNT_MNT_NAMESPACES,
48 UCOUNT_CGROUP_NAMESPACES,
49 UCOUNT_TIME_NAMESPACES,
50 #ifdef CONFIG_INOTIFY_USER
51 UCOUNT_INOTIFY_INSTANCES,
52 UCOUNT_INOTIFY_WATCHES,
53 #endif
54 #ifdef CONFIG_FANOTIFY
55 UCOUNT_FANOTIFY_GROUPS,
56 UCOUNT_FANOTIFY_MARKS,
57 #endif
58 UCOUNT_COUNTS,
59 };
60
61 enum rlimit_type {
62 UCOUNT_RLIMIT_NPROC,
63 UCOUNT_RLIMIT_MSGQUEUE,
64 UCOUNT_RLIMIT_SIGPENDING,
65 UCOUNT_RLIMIT_MEMLOCK,
66 UCOUNT_RLIMIT_COUNTS,
67 };
68
69 struct user_namespace {
70 struct uid_gid_map uid_map;
71 struct uid_gid_map gid_map;
72 struct uid_gid_map projid_map;
73 struct user_namespace *parent;
74 int level;
75 kuid_t owner;
76 kgid_t group;
77 struct ns_common ns;
78 unsigned long flags;
79 /* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
80 * in its effective capability set at the child ns creation time. */
81 bool parent_could_setfcap;
82
83 #ifdef CONFIG_KEYS
84 /* List of joinable keyrings in this namespace. Modification access of
85 * these pointers is controlled by keyring_sem. Once
86 * user_keyring_register is set, it won't be changed, so it can be
87 * accessed directly with READ_ONCE().
88 */
89 struct list_head keyring_name_list;
90 struct key *user_keyring_register;
91 struct rw_semaphore keyring_sem;
92 #endif
93
94 /* Register of per-UID persistent keyrings for this namespace */
95 #ifdef CONFIG_PERSISTENT_KEYRINGS
96 struct key *persistent_keyring_register;
97 #endif
98 struct work_struct work;
99 #ifdef CONFIG_SYSCTL
100 struct ctl_table_set set;
101 struct ctl_table_header *sysctls;
102 #endif
103 struct ucounts *ucounts;
104 long ucount_max[UCOUNT_COUNTS];
105 long rlimit_max[UCOUNT_RLIMIT_COUNTS];
106
107 ANDROID_KABI_RESERVE(1);
108 ANDROID_KABI_RESERVE(2);
109 } __randomize_layout;
110
111 struct ucounts {
112 struct hlist_node node;
113 struct user_namespace *ns;
114 kuid_t uid;
115 atomic_t count;
116 atomic_long_t ucount[UCOUNT_COUNTS];
117 atomic_long_t rlimit[UCOUNT_RLIMIT_COUNTS];
118 };
119
120 extern struct user_namespace init_user_ns;
121 extern struct ucounts init_ucounts;
122
123 bool setup_userns_sysctls(struct user_namespace *ns);
124 void retire_userns_sysctls(struct user_namespace *ns);
125 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
126 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
127 struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
128 struct ucounts * __must_check get_ucounts(struct ucounts *ucounts);
129 void put_ucounts(struct ucounts *ucounts);
130
get_rlimit_value(struct ucounts * ucounts,enum rlimit_type type)131 static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type type)
132 {
133 return atomic_long_read(&ucounts->rlimit[type]);
134 }
135
136 long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
137 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
138 long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type);
139 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type);
140 bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max);
141
get_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type)142 static inline long get_userns_rlimit_max(struct user_namespace *ns, enum rlimit_type type)
143 {
144 return READ_ONCE(ns->rlimit_max[type]);
145 }
146
set_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type,unsigned long max)147 static inline void set_userns_rlimit_max(struct user_namespace *ns,
148 enum rlimit_type type, unsigned long max)
149 {
150 ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX;
151 }
152
153 #ifdef CONFIG_USER_NS
154
get_user_ns(struct user_namespace * ns)155 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
156 {
157 if (ns)
158 refcount_inc(&ns->ns.count);
159 return ns;
160 }
161
162 extern int create_user_ns(struct cred *new);
163 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
164 extern void __put_user_ns(struct user_namespace *ns);
165
put_user_ns(struct user_namespace * ns)166 static inline void put_user_ns(struct user_namespace *ns)
167 {
168 if (ns && refcount_dec_and_test(&ns->ns.count))
169 __put_user_ns(ns);
170 }
171
172 struct seq_operations;
173 extern const struct seq_operations proc_uid_seq_operations;
174 extern const struct seq_operations proc_gid_seq_operations;
175 extern const struct seq_operations proc_projid_seq_operations;
176 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
177 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
178 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
179 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
180 extern int proc_setgroups_show(struct seq_file *m, void *v);
181 extern bool userns_may_setgroups(const struct user_namespace *ns);
182 extern bool in_userns(const struct user_namespace *ancestor,
183 const struct user_namespace *child);
184 extern bool current_in_userns(const struct user_namespace *target_ns);
185 struct ns_common *ns_get_owner(struct ns_common *ns);
186 #else
187
get_user_ns(struct user_namespace * ns)188 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
189 {
190 return &init_user_ns;
191 }
192
create_user_ns(struct cred * new)193 static inline int create_user_ns(struct cred *new)
194 {
195 return -EINVAL;
196 }
197
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)198 static inline int unshare_userns(unsigned long unshare_flags,
199 struct cred **new_cred)
200 {
201 if (unshare_flags & CLONE_NEWUSER)
202 return -EINVAL;
203 return 0;
204 }
205
put_user_ns(struct user_namespace * ns)206 static inline void put_user_ns(struct user_namespace *ns)
207 {
208 }
209
userns_may_setgroups(const struct user_namespace * ns)210 static inline bool userns_may_setgroups(const struct user_namespace *ns)
211 {
212 return true;
213 }
214
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)215 static inline bool in_userns(const struct user_namespace *ancestor,
216 const struct user_namespace *child)
217 {
218 return true;
219 }
220
current_in_userns(const struct user_namespace * target_ns)221 static inline bool current_in_userns(const struct user_namespace *target_ns)
222 {
223 return true;
224 }
225
ns_get_owner(struct ns_common * ns)226 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
227 {
228 return ERR_PTR(-EPERM);
229 }
230 #endif
231
232 #endif /* _LINUX_USER_H */
233