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
21 void sem_init(void);
22 void msg_init(void);
23 void shm_init(void);
24
25 struct ipc_namespace;
26 struct pid_namespace;
27
28 #ifdef CONFIG_POSIX_MQUEUE
29 extern void mq_clear_sbinfo(struct ipc_namespace *ns);
30 extern void mq_put_mnt(struct ipc_namespace *ns);
31 #else
mq_clear_sbinfo(struct ipc_namespace * ns)32 static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
mq_put_mnt(struct ipc_namespace * ns)33 static inline void mq_put_mnt(struct ipc_namespace *ns) { }
34 #endif
35
36 #ifdef CONFIG_SYSVIPC
37 void sem_init_ns(struct ipc_namespace *ns);
38 void msg_init_ns(struct ipc_namespace *ns);
39 void shm_init_ns(struct ipc_namespace *ns);
40
41 void sem_exit_ns(struct ipc_namespace *ns);
42 void msg_exit_ns(struct ipc_namespace *ns);
43 void shm_exit_ns(struct ipc_namespace *ns);
44 #else
sem_init_ns(struct ipc_namespace * ns)45 static inline void sem_init_ns(struct ipc_namespace *ns) { }
msg_init_ns(struct ipc_namespace * ns)46 static inline void msg_init_ns(struct ipc_namespace *ns) { }
shm_init_ns(struct ipc_namespace * ns)47 static inline void shm_init_ns(struct ipc_namespace *ns) { }
48
sem_exit_ns(struct ipc_namespace * ns)49 static inline void sem_exit_ns(struct ipc_namespace *ns) { }
msg_exit_ns(struct ipc_namespace * ns)50 static inline void msg_exit_ns(struct ipc_namespace *ns) { }
shm_exit_ns(struct ipc_namespace * ns)51 static 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 */
58 struct 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 */
77 struct 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
83 struct seq_file;
84 struct ipc_ids;
85
86 void ipc_init_ids(struct ipc_ids *ids);
87 #ifdef CONFIG_PROC_FS
88 void __init ipc_init_proc_interface(const char *path, const char *header,
89 int ids, int (*show)(struct seq_file *, void *));
90 struct 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 */
104 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
105
106 /* must be called with both locks acquired. */
107 void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
108
109 /* must be called with both locks acquired. */
110 void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
111
112 /* must be called with ipcp locked */
113 int 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 */
ipc_get_maxidx(struct ipc_ids * ids)121 static 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 */
141 bool ipc_rcu_getref(struct kern_ipc_perm *ptr);
142 void ipc_rcu_putref(struct kern_ipc_perm *ptr,
143 void (*func)(struct rcu_head *head));
144
145 struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
146
147 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
148 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
149 int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
150 struct 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
ipc_update_pid(struct pid ** pos,struct pid * pid)154 static 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 #ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
164 /* On IA-64, we always use the "64-bit version" of the IPC structures. */
165 # define ipc_parse_version(cmd) IPC_64
166 #else
167 int ipc_parse_version(int *cmd);
168 #endif
169
170 extern void free_msg(struct msg_msg *msg);
171 extern struct msg_msg *load_msg(const void __user *src, size_t len);
172 extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
173 extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
174
ipc_checkid(struct kern_ipc_perm * ipcp,int id)175 static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id)
176 {
177 return ipcid_to_seqx(id) != ipcp->seq;
178 }
179
ipc_lock_object(struct kern_ipc_perm * perm)180 static inline void ipc_lock_object(struct kern_ipc_perm *perm)
181 {
182 spin_lock(&perm->lock);
183 }
184
ipc_unlock_object(struct kern_ipc_perm * perm)185 static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
186 {
187 spin_unlock(&perm->lock);
188 }
189
ipc_assert_locked_object(struct kern_ipc_perm * perm)190 static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
191 {
192 assert_spin_locked(&perm->lock);
193 }
194
ipc_unlock(struct kern_ipc_perm * perm)195 static inline void ipc_unlock(struct kern_ipc_perm *perm)
196 {
197 ipc_unlock_object(perm);
198 rcu_read_unlock();
199 }
200
201 /*
202 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
203 * where the respective ipc_ids.rwsem is not being held down.
204 * Checks whether the ipc object is still around or if it's gone already, as
205 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
206 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
207 * checkpoint case at sys_semtimedop() as noted in code commentary.
208 */
ipc_valid_object(struct kern_ipc_perm * perm)209 static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
210 {
211 return !perm->deleted;
212 }
213
214 struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
215 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
216 const struct ipc_ops *ops, struct ipc_params *params);
217 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
218 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
219
220 #ifdef CONFIG_COMPAT
221 #include <linux/compat.h>
222 struct compat_ipc_perm {
223 key_t key;
224 __compat_uid_t uid;
225 __compat_gid_t gid;
226 __compat_uid_t cuid;
227 __compat_gid_t cgid;
228 compat_mode_t mode;
229 unsigned short seq;
230 };
231
232 void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *);
233 void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *);
234 int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *);
235 int get_compat_ipc64_perm(struct ipc64_perm *,
236 struct compat_ipc64_perm __user *);
237
compat_ipc_parse_version(int * cmd)238 static inline int compat_ipc_parse_version(int *cmd)
239 {
240 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
241 int version = *cmd & IPC_64;
242 *cmd &= ~IPC_64;
243 return version;
244 #else
245 return IPC_64;
246 #endif
247 }
248 #endif
249
250 /* for __ARCH_WANT_SYS_IPC */
251 long ksys_semtimedop(int semid, struct sembuf __user *tsops,
252 unsigned int nsops,
253 const struct __kernel_timespec __user *timeout);
254 long ksys_semget(key_t key, int nsems, int semflg);
255 long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg);
256 long ksys_msgget(key_t key, int msgflg);
257 long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);
258 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
259 long msgtyp, int msgflg);
260 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
261 int msgflg);
262 long ksys_shmget(key_t key, size_t size, int shmflg);
263 long ksys_shmdt(char __user *shmaddr);
264 long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf);
265
266 /* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */
267 long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
268 unsigned int nsops,
269 const struct compat_timespec __user *timeout);
270 #ifdef CONFIG_COMPAT
271 long compat_ksys_semctl(int semid, int semnum, int cmd, int arg);
272 long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr);
273 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
274 compat_long_t msgtyp, int msgflg);
275 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
276 compat_ssize_t msgsz, int msgflg);
277 long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr);
278 #endif /* CONFIG_COMPAT */
279
280 #endif
281
