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