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_RLIMIT_NPROC,
59 UCOUNT_RLIMIT_MSGQUEUE,
60 UCOUNT_RLIMIT_SIGPENDING,
61 UCOUNT_RLIMIT_MEMLOCK,
62 UCOUNT_COUNTS,
63 };
64
65 #define MAX_PER_NAMESPACE_UCOUNTS UCOUNT_RLIMIT_NPROC
66
67 struct user_namespace {
68 struct uid_gid_map uid_map;
69 struct uid_gid_map gid_map;
70 struct uid_gid_map projid_map;
71 struct user_namespace *parent;
72 int level;
73 kuid_t owner;
74 kgid_t group;
75 struct ns_common ns;
76 unsigned long flags;
77 /* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
78 * in its effective capability set at the child ns creation time. */
79 bool parent_could_setfcap;
80
81 #ifdef CONFIG_KEYS
82 /* List of joinable keyrings in this namespace. Modification access of
83 * these pointers is controlled by keyring_sem. Once
84 * user_keyring_register is set, it won't be changed, so it can be
85 * accessed directly with READ_ONCE().
86 */
87 struct list_head keyring_name_list;
88 struct key *user_keyring_register;
89 struct rw_semaphore keyring_sem;
90 #endif
91
92 /* Register of per-UID persistent keyrings for this namespace */
93 #ifdef CONFIG_PERSISTENT_KEYRINGS
94 struct key *persistent_keyring_register;
95 #endif
96 struct work_struct work;
97 #ifdef CONFIG_SYSCTL
98 struct ctl_table_set set;
99 struct ctl_table_header *sysctls;
100 #endif
101 struct ucounts *ucounts;
102 long ucount_max[UCOUNT_COUNTS];
103
104 ANDROID_KABI_RESERVE(1);
105 ANDROID_KABI_RESERVE(2);
106 } __randomize_layout;
107
108 struct ucounts {
109 struct hlist_node node;
110 struct user_namespace *ns;
111 kuid_t uid;
112 atomic_t count;
113 atomic_long_t ucount[UCOUNT_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_ucounts_value(struct ucounts * ucounts,enum ucount_type type)127 static inline long get_ucounts_value(struct ucounts *ucounts, enum ucount_type type)
128 {
129 return atomic_long_read(&ucounts->ucount[type]);
130 }
131
132 long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v);
133 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v);
134 long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum ucount_type type);
135 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum ucount_type type);
136 bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long max);
137
set_rlimit_ucount_max(struct user_namespace * ns,enum ucount_type type,unsigned long max)138 static inline void set_rlimit_ucount_max(struct user_namespace *ns,
139 enum ucount_type type, unsigned long max)
140 {
141 ns->ucount_max[type] = max <= LONG_MAX ? max : LONG_MAX;
142 }
143
144 #ifdef CONFIG_USER_NS
145
get_user_ns(struct user_namespace * ns)146 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
147 {
148 if (ns)
149 refcount_inc(&ns->ns.count);
150 return ns;
151 }
152
153 extern int create_user_ns(struct cred *new);
154 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
155 extern void __put_user_ns(struct user_namespace *ns);
156
put_user_ns(struct user_namespace * ns)157 static inline void put_user_ns(struct user_namespace *ns)
158 {
159 if (ns && refcount_dec_and_test(&ns->ns.count))
160 __put_user_ns(ns);
161 }
162
163 struct seq_operations;
164 extern const struct seq_operations proc_uid_seq_operations;
165 extern const struct seq_operations proc_gid_seq_operations;
166 extern const struct seq_operations proc_projid_seq_operations;
167 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
168 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
169 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
170 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
171 extern int proc_setgroups_show(struct seq_file *m, void *v);
172 extern bool userns_may_setgroups(const struct user_namespace *ns);
173 extern bool in_userns(const struct user_namespace *ancestor,
174 const struct user_namespace *child);
175 extern bool current_in_userns(const struct user_namespace *target_ns);
176 struct ns_common *ns_get_owner(struct ns_common *ns);
177 #else
178
get_user_ns(struct user_namespace * ns)179 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
180 {
181 return &init_user_ns;
182 }
183
create_user_ns(struct cred * new)184 static inline int create_user_ns(struct cred *new)
185 {
186 return -EINVAL;
187 }
188
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)189 static inline int unshare_userns(unsigned long unshare_flags,
190 struct cred **new_cred)
191 {
192 if (unshare_flags & CLONE_NEWUSER)
193 return -EINVAL;
194 return 0;
195 }
196
put_user_ns(struct user_namespace * ns)197 static inline void put_user_ns(struct user_namespace *ns)
198 {
199 }
200
userns_may_setgroups(const struct user_namespace * ns)201 static inline bool userns_may_setgroups(const struct user_namespace *ns)
202 {
203 return true;
204 }
205
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)206 static inline bool in_userns(const struct user_namespace *ancestor,
207 const struct user_namespace *child)
208 {
209 return true;
210 }
211
current_in_userns(const struct user_namespace * target_ns)212 static inline bool current_in_userns(const struct user_namespace *target_ns)
213 {
214 return true;
215 }
216
ns_get_owner(struct ns_common * ns)217 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
218 {
219 return ERR_PTR(-EPERM);
220 }
221 #endif
222
223 #endif /* _LINUX_USER_H */
224