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/rculist_nulls.h>
9 #include <linux/sched.h>
10 #include <linux/workqueue.h>
11 #include <linux/rcuref.h>
12 #include <linux/rwsem.h>
13 #include <linux/sysctl.h>
14 #include <linux/err.h>
15
16 #define UID_GID_MAP_MAX_BASE_EXTENTS 5
17 #define UID_GID_MAP_MAX_EXTENTS 340
18
19 struct uid_gid_extent {
20 u32 first;
21 u32 lower_first;
22 u32 count;
23 };
24
25 struct uid_gid_map { /* 64 bytes -- 1 cache line */
26 union {
27 struct {
28 struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
29 u32 nr_extents;
30 };
31 struct {
32 struct uid_gid_extent *forward __counted_by_ptr(nr_extents);
33 struct uid_gid_extent *reverse __counted_by_ptr(nr_extents);
34 };
35 };
36 };
37
38 #define USERNS_SETGROUPS_ALLOWED 1UL
39
40 #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
41
42 struct ucounts;
43
44 enum ucount_type {
45 UCOUNT_USER_NAMESPACES,
46 UCOUNT_PID_NAMESPACES,
47 UCOUNT_UTS_NAMESPACES,
48 UCOUNT_IPC_NAMESPACES,
49 UCOUNT_NET_NAMESPACES,
50 UCOUNT_MNT_NAMESPACES,
51 UCOUNT_CGROUP_NAMESPACES,
52 UCOUNT_TIME_NAMESPACES,
53 #ifdef CONFIG_INOTIFY_USER
54 UCOUNT_INOTIFY_INSTANCES,
55 UCOUNT_INOTIFY_WATCHES,
56 #endif
57 #ifdef CONFIG_FANOTIFY
58 UCOUNT_FANOTIFY_GROUPS,
59 UCOUNT_FANOTIFY_MARKS,
60 #endif
61 #if IS_ENABLED(CONFIG_BINFMT_MISC)
62 UCOUNT_BINFMT_MISC_INTERPRETERS,
63 #endif
64 UCOUNT_COUNTS,
65 };
66
67 enum rlimit_type {
68 UCOUNT_RLIMIT_NPROC,
69 UCOUNT_RLIMIT_MSGQUEUE,
70 UCOUNT_RLIMIT_SIGPENDING,
71 UCOUNT_RLIMIT_MEMLOCK,
72 UCOUNT_RLIMIT_COUNTS,
73 };
74
75 #if IS_ENABLED(CONFIG_BINFMT_MISC)
76 struct binfmt_misc;
77 #endif
78
79 struct user_namespace {
80 struct uid_gid_map uid_map;
81 struct uid_gid_map gid_map;
82 struct uid_gid_map projid_map;
83 struct user_namespace *parent;
84 int level;
85 kuid_t owner;
86 kgid_t group;
87 struct ns_common ns;
88 unsigned long flags;
89 /* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
90 * in its effective capability set at the child ns creation time. */
91 bool parent_could_setfcap;
92
93 #ifdef CONFIG_KEYS
94 /* List of joinable keyrings in this namespace. Modification access of
95 * these pointers is controlled by keyring_sem. Once
96 * user_keyring_register is set, it won't be changed, so it can be
97 * accessed directly with READ_ONCE().
98 */
99 struct list_head keyring_name_list;
100 struct key *user_keyring_register;
101 struct rw_semaphore keyring_sem;
102 #endif
103
104 /* Register of per-UID persistent keyrings for this namespace */
105 #ifdef CONFIG_PERSISTENT_KEYRINGS
106 struct key *persistent_keyring_register;
107 #endif
108 struct work_struct work;
109 #ifdef CONFIG_SYSCTL
110 struct ctl_table_set set;
111 struct ctl_table_header *sysctls;
112 #endif
113 struct ucounts *ucounts;
114 long ucount_max[UCOUNT_COUNTS];
115 long rlimit_max[UCOUNT_RLIMIT_COUNTS];
116
117 #if IS_ENABLED(CONFIG_BINFMT_MISC)
118 struct binfmt_misc *binfmt_misc;
119 #endif
120 } __randomize_layout;
121
122 struct ucounts {
123 struct hlist_nulls_node node;
124 struct user_namespace *ns;
125 kuid_t uid;
126 struct rcu_head rcu;
127 rcuref_t count;
128 atomic_long_t ucount[UCOUNT_COUNTS];
129 atomic_long_t rlimit[UCOUNT_RLIMIT_COUNTS];
130 };
131
132 extern struct user_namespace init_user_ns;
133 extern struct ucounts init_ucounts;
134
135 bool setup_userns_sysctls(struct user_namespace *ns);
136 void retire_userns_sysctls(struct user_namespace *ns);
137 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
138 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
139 struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
140 void put_ucounts(struct ucounts *ucounts);
141
get_ucounts(struct ucounts * ucounts)142 static inline struct ucounts * __must_check get_ucounts(struct ucounts *ucounts)
143 {
144 if (rcuref_get(&ucounts->count))
145 return ucounts;
146 return NULL;
147 }
148
get_rlimit_value(struct ucounts * ucounts,enum rlimit_type type)149 static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type type)
150 {
151 return atomic_long_read(&ucounts->rlimit[type]);
152 }
153
154 long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
155 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
156 long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type,
157 bool override_rlimit);
158 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type);
159 bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max);
160
get_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type)161 static inline long get_userns_rlimit_max(struct user_namespace *ns, enum rlimit_type type)
162 {
163 return READ_ONCE(ns->rlimit_max[type]);
164 }
165
set_userns_rlimit_max(struct user_namespace * ns,enum rlimit_type type,unsigned long max)166 static inline void set_userns_rlimit_max(struct user_namespace *ns,
167 enum rlimit_type type, unsigned long max)
168 {
169 ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX;
170 }
171
to_user_ns(struct ns_common * ns)172 static inline struct user_namespace *to_user_ns(struct ns_common *ns)
173 {
174 return container_of(ns, struct user_namespace, ns);
175 }
176
177 #ifdef CONFIG_USER_NS
178
get_user_ns(struct user_namespace * ns)179 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
180 {
181 if (ns)
182 ns_ref_inc(ns);
183 return ns;
184 }
185
186 extern int create_user_ns(struct cred *new);
187 extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
188 extern void __put_user_ns(struct user_namespace *ns);
189
put_user_ns(struct user_namespace * ns)190 static inline void put_user_ns(struct user_namespace *ns)
191 {
192 if (ns && ns_ref_put(ns))
193 __put_user_ns(ns);
194 }
195
196 struct seq_operations;
197 extern const struct seq_operations proc_uid_seq_operations;
198 extern const struct seq_operations proc_gid_seq_operations;
199 extern const struct seq_operations proc_projid_seq_operations;
200 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
201 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
202 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
203 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
204 extern int proc_setgroups_show(struct seq_file *m, void *v);
205 extern bool userns_may_setgroups(const struct user_namespace *ns);
206 extern bool in_userns(const struct user_namespace *ancestor,
207 const struct user_namespace *child);
208 extern bool current_in_userns(const struct user_namespace *target_ns);
209 struct ns_common *ns_get_owner(struct ns_common *ns);
210
211 #if IS_ENABLED(CONFIG_KUNIT)
212 extern int uid_gid_map_insert_extent(struct uid_gid_map *map,
213 struct uid_gid_extent *extent);
214 extern int uid_gid_map_sort(struct uid_gid_map *map);
215 #endif /* CONFIG_KUNIT */
216
217 #else
218
get_user_ns(struct user_namespace * ns)219 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
220 {
221 return &init_user_ns;
222 }
223
create_user_ns(struct cred * new)224 static inline int create_user_ns(struct cred *new)
225 {
226 return -EINVAL;
227 }
228
unshare_userns(unsigned long unshare_flags,struct cred ** new_cred)229 static inline int unshare_userns(unsigned long unshare_flags,
230 struct cred **new_cred)
231 {
232 if (unshare_flags & CLONE_NEWUSER)
233 return -EINVAL;
234 return 0;
235 }
236
put_user_ns(struct user_namespace * ns)237 static inline void put_user_ns(struct user_namespace *ns)
238 {
239 }
240
userns_may_setgroups(const struct user_namespace * ns)241 static inline bool userns_may_setgroups(const struct user_namespace *ns)
242 {
243 return true;
244 }
245
in_userns(const struct user_namespace * ancestor,const struct user_namespace * child)246 static inline bool in_userns(const struct user_namespace *ancestor,
247 const struct user_namespace *child)
248 {
249 return true;
250 }
251
current_in_userns(const struct user_namespace * target_ns)252 static inline bool current_in_userns(const struct user_namespace *target_ns)
253 {
254 return true;
255 }
256
ns_get_owner(struct ns_common * ns)257 static inline struct ns_common *ns_get_owner(struct ns_common *ns)
258 {
259 return ERR_PTR(-EPERM);
260 }
261 #endif
262
263 #endif /* _LINUX_USER_H */
264