1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * linux/ipc/util.h
4 * Copyright (C) 1999 Christoph Rohland
5 *
6 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
7 * namespaces support. 2006 OpenVZ, SWsoft Inc.
8 * Pavel Emelianov <xemul@openvz.org>
9 */
10
11#ifndef _IPC_UTIL_H
12#define _IPC_UTIL_H
13
14#include <linux/unistd.h>
15#include <linux/err.h>
16#include <linux/ipc_namespace.h>
17
18#define IPCMNI 32768 /* <= MAX_INT limit for ipc arrays (including sysctl changes) */
19#define SEQ_MULTIPLIER (IPCMNI)
20
21void sem_init(void);
22void msg_init(void);
23void shm_init(void);
24
25struct ipc_namespace;
26struct pid_namespace;
27
28#ifdef CONFIG_POSIX_MQUEUE
29extern void mq_clear_sbinfo(struct ipc_namespace *ns);
30extern void mq_put_mnt(struct ipc_namespace *ns);
31#else
32static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
33static inline void mq_put_mnt(struct ipc_namespace *ns) { }
34#endif
35
36#ifdef CONFIG_SYSVIPC
37void sem_init_ns(struct ipc_namespace *ns);
38void msg_init_ns(struct ipc_namespace *ns);
39void shm_init_ns(struct ipc_namespace *ns);
40
41void sem_exit_ns(struct ipc_namespace *ns);
42void msg_exit_ns(struct ipc_namespace *ns);
43void shm_exit_ns(struct ipc_namespace *ns);
44#else
45static inline void sem_init_ns(struct ipc_namespace *ns) { }
46static inline void msg_init_ns(struct ipc_namespace *ns) { }
47static inline void shm_init_ns(struct ipc_namespace *ns) { }
48
49static inline void sem_exit_ns(struct ipc_namespace *ns) { }
50static inline void msg_exit_ns(struct ipc_namespace *ns) { }
51static inline void shm_exit_ns(struct ipc_namespace *ns) { }
52#endif
53
54/*
55 * Structure that holds the parameters needed by the ipc operations
56 * (see after)
57 */
58struct ipc_params {
59 key_t key;
60 int flg;
61 union {
62 size_t size; /* for shared memories */
63 int nsems; /* for semaphores */
64 } u; /* holds the getnew() specific param */
65};
66
67/*
68 * Structure that holds some ipc operations. This structure is used to unify
69 * the calls to sys_msgget(), sys_semget(), sys_shmget()
70 * . routine to call to create a new ipc object. Can be one of newque,
71 * newary, newseg
72 * . routine to call to check permissions for a new ipc object.
73 * Can be one of security_msg_associate, security_sem_associate,
74 * security_shm_associate
75 * . routine to call for an extra check if needed
76 */
77struct ipc_ops {
78 int (*getnew)(struct ipc_namespace *, struct ipc_params *);
79 int (*associate)(struct kern_ipc_perm *, int);
80 int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *);
81};
82
83struct seq_file;
84struct ipc_ids;
85
86void ipc_init_ids(struct ipc_ids *ids);
87#ifdef CONFIG_PROC_FS
88void __init ipc_init_proc_interface(const char *path, const char *header,
89 int ids, int (*show)(struct seq_file *, void *));
90struct pid_namespace *ipc_seq_pid_ns(struct seq_file *);
91#else
92#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
93#endif
94
95#define IPC_SEM_IDS 0
96#define IPC_MSG_IDS 1
97#define IPC_SHM_IDS 2
98
99#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
100#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
101#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)
102
103/* must be called with ids->rwsem acquired for writing */
104int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
105
106/* must be called with both locks acquired. */
107void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
108
109/* must be called with both locks acquired. */
110void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
111
112/* must be called with ipcp locked */
113int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
114
115/**
116 * ipc_get_maxidx - get the highest assigned index
117 * @ids: ipc identifier set
118 *
119 * Called with ipc_ids.rwsem held for reading.
120 */
121static inline int ipc_get_maxidx(struct ipc_ids *ids)
122{
123 if (ids->in_use == 0)
124 return -1;
125
126 if (ids->in_use == IPCMNI)
127 return IPCMNI - 1;
128
129 return ids->max_idx;
130}
131
132/*
133 * For allocation that need to be freed by RCU.
134 * Objects are reference counted, they start with reference count 1.
135 * getref increases the refcount, the putref call that reduces the recount
136 * to 0 schedules the rcu destruction. Caller must guarantee locking.
137 *
138 * refcount is initialized by ipc_addid(), before that point call_rcu()
139 * must be used.
140 */
141bool ipc_rcu_getref(struct kern_ipc_perm *ptr);
142void ipc_rcu_putref(struct kern_ipc_perm *ptr,
143 void (*func)(struct rcu_head *head));
144
145struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
146
147void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
148void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
149int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
150struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
151 struct ipc_ids *ids, int id, int cmd,
152 struct ipc64_perm *perm, int extra_perm);
153
154static inline void ipc_update_pid(struct pid **pos, struct pid *pid)
155{
156 struct pid *old = *pos;
157 if (old != pid) {
158 *pos = get_pid(pid);
159 put_pid(old);
160 }
161}
162
163#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
164int ipc_parse_version(int *cmd);
165#endif
166
167extern void free_msg(struct msg_msg *msg);
168extern struct msg_msg *load_msg(const void __user *src, size_t len);
169extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
170extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
171
172static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id)
173{
174 return ipcid_to_seqx(id) != ipcp->seq;
175}
176
177static inline void ipc_lock_object(struct kern_ipc_perm *perm)
178{
179 spin_lock(&perm->lock);
180}
181
182static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
183{
184 spin_unlock(&perm->lock);
185}
186
187static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
188{
189 assert_spin_locked(&perm->lock);
190}
191
192static inline void ipc_unlock(struct kern_ipc_perm *perm)
193{
194 ipc_unlock_object(perm);
195 rcu_read_unlock();
196}
197
198/*
199 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
200 * where the respective ipc_ids.rwsem is not being held down.
201 * Checks whether the ipc object is still around or if it's gone already, as
202 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
203 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
204 * checkpoint case at sys_semtimedop() as noted in code commentary.
205 */
206static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
207{
208 return !perm->deleted;
209}
210
211struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
212int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
213 const struct ipc_ops *ops, struct ipc_params *params);
214void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
215 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
216
217static inline int sem_check_semmni(struct ipc_namespace *ns) {
218 /*
219 * Check semmni range [0, IPCMNI]
220 * semmni is the last element of sem_ctls[4] array
221 */
222 return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > IPCMNI))
223 ? -ERANGE : 0;
224}
225
226#ifdef CONFIG_COMPAT
227#include <linux/compat.h>
228struct compat_ipc_perm {
229 key_t key;
230 __compat_uid_t uid;
231 __compat_gid_t gid;
232 __compat_uid_t cuid;
233 __compat_gid_t cgid;
234 compat_mode_t mode;
235 unsigned short seq;
236};
237
238void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *);
239void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *);
240int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *);
241int get_compat_ipc64_perm(struct ipc64_perm *,
242 struct compat_ipc64_perm __user *);
243
244static inline int compat_ipc_parse_version(int *cmd)
245{
246 int version = *cmd & IPC_64;
247 *cmd &= ~IPC_64;
248 return version;
249}
250#endif
251
252/* for __ARCH_WANT_SYS_IPC */
253long ksys_semtimedop(int semid, struct sembuf __user *tsops,
254 unsigned int nsops,
255 const struct __kernel_timespec __user *timeout);
256long ksys_semget(key_t key, int nsems, int semflg);
257long ksys_old_semctl(int semid, int semnum, int cmd, unsigned long arg);
258long ksys_msgget(key_t key, int msgflg);
259long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);
260long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
261 long msgtyp, int msgflg);
262long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
263 int msgflg);
264long ksys_shmget(key_t key, size_t size, int shmflg);
265long ksys_shmdt(char __user *shmaddr);
266long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf);
267
268/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */
269long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
270 unsigned int nsops,
271 const struct old_timespec32 __user *timeout);
272#ifdef CONFIG_COMPAT
273long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg);
274long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr);
275long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
276 compat_long_t msgtyp, int msgflg);
277long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
278 compat_ssize_t msgsz, int msgflg);
279long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr);
280#endif /* CONFIG_COMPAT */
281
282#endif
283