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