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 union {
26 struct {
27 struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
28 u32 nr_extents;
29 };
30 struct {
31 struct uid_gid_extent *forward;
32 struct uid_gid_extent *reverse;
33 };
34 };
35 };
36
37 #define USERNS_SETGROUPS_ALLOWED 1UL
38
39 #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
40
41 struct ucounts;
42
43 enum ucount_type {
44 UCOUNT_USER_NAMESPACES,
45 UCOUNT_PID_NAMESPACES,
46 UCOUNT_UTS_NAMESPACES,
47 UCOUNT_IPC_NAMESPACES,
48 UCOUNT_NET_NAMESPACES,
49 UCOUNT_MNT_NAMESPACES,
50 UCOUNT_CGROUP_NAMESPACES,
51 UCOUNT_TIME_NAMESPACES,
52 #ifdef CONFIG_INOTIFY_USER
53 UCOUNT_INOTIFY_INSTANCES,
54 UCOUNT_INOTIFY_WATCHES,
55 #endif
56 #ifdef CONFIG_FANOTIFY
57 UCOUNT_FANOTIFY_GROUPS,
58 UCOUNT_FANOTIFY_MARKS,
59 #endif
60 UCOUNT_COUNTS,
61 };
62
63 enum rlimit_type {
64 UCOUNT_RLIMIT_NPROC,
65 UCOUNT_RLIMIT_MSGQUEUE,
66 UCOUNT_RLIMIT_SIGPENDING,
67 UCOUNT_RLIMIT_MEMLOCK,
68 UCOUNT_RLIMIT_COUNTS,
69 };
70
71 #if IS_ENABLED(CONFIG_BINFMT_MISC)
72 struct binfmt_misc;
73 #endif
74
75 struct user_namespace {
76 struct uid_gid_map uid_map;
77 struct uid_gid_map gid_map;
78 struct uid_gid_map projid_map;
79 struct user_namespace *parent;
80 int level;
81 kuid_t owner;
82 kgid_t group;
83 struct ns_common ns;
84 unsigned long flags;
85 /* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
86 * in its effective capability set at the child ns creation time. */
87 bool parent_could_setfcap;
88
89 #ifdef CONFIG_KEYS
90 /* List of joinable keyrings in this namespace. Modification access of
91 * these pointers is controlled by keyring_sem. Once
92 * user_keyring_register is set, it won't be changed, so it can be
93 * accessed directly with READ_ONCE().
94 */
95 struct list_head keyring_name_list;
96 struct key *user_keyring_register;
97 struct rw_semaphore keyring_sem;
98 #endif
99
100 /* Register of per-UID persistent keyrings for this namespace */
101 #ifdef CONFIG_PERSISTENT_KEYRINGS
102 struct key *persistent_keyring_register;
103 #endif
104 struct work_struct work;
105 #ifdef CONFIG_SYSCTL
106 struct ctl_table_set set;
107 struct ctl_table_header *sysctls;
108 #endif
109 struct ucounts *ucounts;
110 long ucount_max[UCOUNT_COUNTS];
111 long rlimit_max[UCOUNT_RLIMIT_COUNTS];
112
113 #if IS_ENABLED(CONFIG_BINFMT_MISC)
114 struct binfmt_misc *binfmt_misc;
115 #endif
116 ANDROID_KABI_RESERVE(1);
117 ANDROID_KABI_RESERVE(2);
118 } __randomize_layout;
119
120 struct ucounts {
121 struct hlist_node node;
122 struct user_namespace *ns;
123 kuid_t uid;
124 atomic_t count;
125 atomic_long_t ucount[UCOUNT_COUNTS];
126 atomic_long_t rlimit[UCOUNT_RLIMIT_COUNTS];
127 };
128
129 extern struct user_namespace init_user_ns;
130 extern struct ucounts init_ucounts;
131
132 bool setup_userns_sysctls(struct user_namespace *ns);
133 void retire_userns_sysctls(struct user_namespace *ns);
134 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
135 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
136 struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
137 struct ucounts * __must_check get_ucounts(struct ucounts *ucounts);
138 void put_ucounts(struct ucounts *ucounts);
139
get_rlimit_value(struct ucounts * ucounts,enum rlimit_type type)140 static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type type)
141 {
142 return atomic_long_read(&ucounts->rlimit[type]);
143 }
144
145 long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
146 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
147 long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type,
148 bool override_rlimit);
149 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type);
150 bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max);
151
get_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type)152 static inline long get_userns_rlimit_max(struct user_namespace *ns, enum rlimit_type type)
153 {
154 return READ_ONCE(ns->rlimit_max[type]);
155 }
156
set_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type,unsigned long max)157 static inline void set_userns_rlimit_max(struct user_namespace *ns,
158 enum rlimit_type type, unsigned long max)
159 {
160 ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX;
161 }
162
163 #ifdef CONFIG_USER_NS
164
get_user_ns(struct user_namespace * ns)165 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
166 {
167 if (ns)
168 refcount_inc(&ns->ns.count);
169 return ns;
170 }
171
172 extern int create_user_ns(struct cred *new);
173 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
174 extern void __put_user_ns(struct user_namespace *ns);
175
put_user_ns(struct user_namespace * ns)176 static inline void put_user_ns(struct user_namespace *ns)
177 {
178 if (ns && refcount_dec_and_test(&ns->ns.count))
179 __put_user_ns(ns);
180 }
181
182 struct seq_operations;
183 extern const struct seq_operations proc_uid_seq_operations;
184 extern const struct seq_operations proc_gid_seq_operations;
185 extern const struct seq_operations proc_projid_seq_operations;
186 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
187 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
188 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
189 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
190 extern int proc_setgroups_show(struct seq_file *m, void *v);
191 extern bool userns_may_setgroups(const struct user_namespace *ns);
192 extern bool in_userns(const struct user_namespace *ancestor,
193 const struct user_namespace *child);
194 extern bool current_in_userns(const struct user_namespace *target_ns);
195 struct ns_common *ns_get_owner(struct ns_common *ns);
196 #else
197
get_user_ns(struct user_namespace * ns)198 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
199 {
200 return &init_user_ns;
201 }
202
create_user_ns(struct cred * new)203 static inline int create_user_ns(struct cred *new)
204 {
205 return -EINVAL;
206 }
207
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)208 static inline int unshare_userns(unsigned long unshare_flags,
209 struct cred **new_cred)
210 {
211 if (unshare_flags & CLONE_NEWUSER)
212 return -EINVAL;
213 return 0;
214 }
215
put_user_ns(struct user_namespace * ns)216 static inline void put_user_ns(struct user_namespace *ns)
217 {
218 }
219
userns_may_setgroups(const struct user_namespace * ns)220 static inline bool userns_may_setgroups(const struct user_namespace *ns)
221 {
222 return true;
223 }
224
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)225 static inline bool in_userns(const struct user_namespace *ancestor,
226 const struct user_namespace *child)
227 {
228 return true;
229 }
230
current_in_userns(const struct user_namespace * target_ns)231 static inline bool current_in_userns(const struct user_namespace *target_ns)
232 {
233 return true;
234 }
235
ns_get_owner(struct ns_common * ns)236 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
237 {
238 return ERR_PTR(-EPERM);
239 }
240 #endif
241
242 #endif /* _LINUX_USER_H */
243