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b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
1da177e4
LT
2/*
3 * linux/ipc/util.h
4 * Copyright (C) 1999 Christoph Rohland
5 *
624dffcb 6 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
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7 * namespaces support. 2006 OpenVZ, SWsoft Inc.
8 * Pavel Emelianov <xemul@openvz.org>
1da177e4
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9 */
10
11#ifndef _IPC_UTIL_H
12#define _IPC_UTIL_H
13
232086b1 14#include <linux/unistd.h>
023a5355 15#include <linux/err.h>
15df03c8 16#include <linux/ipc_namespace.h>
7ca7e564 17
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18/*
19 * The IPC ID contains 2 separate numbers - index and sequence number.
20 * By default,
21 * bits 0-14: index (32k, 15 bits)
22 * bits 15-30: sequence number (64k, 16 bits)
23 *
24 * When IPCMNI extension mode is turned on, the composition changes:
25 * bits 0-23: index (16M, 24 bits)
26 * bits 24-30: sequence number (128, 7 bits)
27 */
28#define IPCMNI_SHIFT 15
29#define IPCMNI_EXTEND_SHIFT 24
99db46ea 30#define IPCMNI_EXTEND_MIN_CYCLE (RADIX_TREE_MAP_SIZE * RADIX_TREE_MAP_SIZE)
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31#define IPCMNI (1 << IPCMNI_SHIFT)
32#define IPCMNI_EXTEND (1 << IPCMNI_EXTEND_SHIFT)
33
34#ifdef CONFIG_SYSVIPC_SYSCTL
35extern int ipc_mni;
36extern int ipc_mni_shift;
99db46ea 37extern int ipc_min_cycle;
5ac893b8 38
3278a2c2 39#define ipcmni_seq_shift() ipc_mni_shift
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40#define IPCMNI_IDX_MASK ((1 << ipc_mni_shift) - 1)
41
42#else /* CONFIG_SYSVIPC_SYSCTL */
43
44#define ipc_mni IPCMNI
99db46ea 45#define ipc_min_cycle ((int)RADIX_TREE_MAP_SIZE)
3278a2c2 46#define ipcmni_seq_shift() IPCMNI_SHIFT
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47#define IPCMNI_IDX_MASK ((1 << IPCMNI_SHIFT) - 1)
48#endif /* CONFIG_SYSVIPC_SYSCTL */
1da177e4 49
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50void sem_init(void);
51void msg_init(void);
239521f3 52void shm_init(void);
1da177e4 53
ae5e1b22 54struct ipc_namespace;
03f1fc09 55struct pid_namespace;
ae5e1b22 56
614b84cf 57#ifdef CONFIG_POSIX_MQUEUE
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58extern void mq_clear_sbinfo(struct ipc_namespace *ns);
59extern void mq_put_mnt(struct ipc_namespace *ns);
614b84cf 60#else
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61static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
62static inline void mq_put_mnt(struct ipc_namespace *ns) { }
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63#endif
64
65#ifdef CONFIG_SYSVIPC
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66void sem_init_ns(struct ipc_namespace *ns);
67void msg_init_ns(struct ipc_namespace *ns);
68void shm_init_ns(struct ipc_namespace *ns);
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69
70void sem_exit_ns(struct ipc_namespace *ns);
71void msg_exit_ns(struct ipc_namespace *ns);
72void shm_exit_ns(struct ipc_namespace *ns);
614b84cf 73#else
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DB
74static inline void sem_init_ns(struct ipc_namespace *ns) { }
75static inline void msg_init_ns(struct ipc_namespace *ns) { }
76static inline void shm_init_ns(struct ipc_namespace *ns) { }
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77
78static inline void sem_exit_ns(struct ipc_namespace *ns) { }
79static inline void msg_exit_ns(struct ipc_namespace *ns) { }
80static inline void shm_exit_ns(struct ipc_namespace *ns) { }
81#endif
73ea4130 82
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83/*
84 * Structure that holds the parameters needed by the ipc operations
85 * (see after)
86 */
87struct ipc_params {
88 key_t key;
89 int flg;
90 union {
91 size_t size; /* for shared memories */
92 int nsems; /* for semaphores */
93 } u; /* holds the getnew() specific param */
94};
95
96/*
97 * Structure that holds some ipc operations. This structure is used to unify
98 * the calls to sys_msgget(), sys_semget(), sys_shmget()
99 * . routine to call to create a new ipc object. Can be one of newque,
100 * newary, newseg
f4566f04 101 * . routine to call to check permissions for a new ipc object.
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102 * Can be one of security_msg_associate, security_sem_associate,
103 * security_shm_associate
104 * . routine to call for an extra check if needed
105 */
106struct ipc_ops {
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107 int (*getnew)(struct ipc_namespace *, struct ipc_params *);
108 int (*associate)(struct kern_ipc_perm *, int);
109 int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *);
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110};
111
ae781774 112struct seq_file;
ed2ddbf8 113struct ipc_ids;
7d69a1f4 114
eae04d25 115void ipc_init_ids(struct ipc_ids *ids);
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116#ifdef CONFIG_PROC_FS
117void __init ipc_init_proc_interface(const char *path, const char *header,
73ea4130 118 int ids, int (*show)(struct seq_file *, void *));
03f1fc09 119struct pid_namespace *ipc_seq_pid_ns(struct seq_file *);
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120#else
121#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
122#endif
1da177e4 123
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124#define IPC_SEM_IDS 0
125#define IPC_MSG_IDS 1
126#define IPC_SHM_IDS 2
127
5ac893b8 128#define ipcid_to_idx(id) ((id) & IPCMNI_IDX_MASK)
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129#define ipcid_to_seqx(id) ((id) >> ipcmni_seq_shift())
130#define ipcid_seq_max() (INT_MAX >> ipcmni_seq_shift())
ce621f5b 131
d9a605e4 132/* must be called with ids->rwsem acquired for writing */
7ca7e564 133int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
3e148c79 134
1da177e4 135/* must be called with both locks acquired. */
7ca7e564 136void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
1da177e4 137
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138/* must be called with both locks acquired. */
139void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
140
f4566f04 141/* must be called with ipcp locked */
b0e77598 142int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
1da177e4 143
15df03c8 144/**
27c331a1 145 * ipc_get_maxidx - get the highest assigned index
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146 * @ids: ipc identifier set
147 *
148 * Called with ipc_ids.rwsem held for reading.
149 */
27c331a1 150static inline int ipc_get_maxidx(struct ipc_ids *ids)
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151{
152 if (ids->in_use == 0)
153 return -1;
154
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155 if (ids->in_use == ipc_mni)
156 return ipc_mni - 1;
15df03c8 157
27c331a1 158 return ids->max_idx;
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159}
160
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161/*
162 * For allocation that need to be freed by RCU.
163 * Objects are reference counted, they start with reference count 1.
164 * getref increases the refcount, the putref call that reduces the recount
165 * to 0 schedules the rcu destruction. Caller must guarantee locking.
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166 *
167 * refcount is initialized by ipc_addid(), before that point call_rcu()
168 * must be used.
1da177e4 169 */
2a9d6481 170bool ipc_rcu_getref(struct kern_ipc_perm *ptr);
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171void ipc_rcu_putref(struct kern_ipc_perm *ptr,
172 void (*func)(struct rcu_head *head));
1da177e4 173
55b7ae50 174struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
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LT
175
176void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
177void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
1efdb69b 178int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
4241c1a3 179struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
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180 struct ipc_ids *ids, int id, int cmd,
181 struct ipc64_perm *perm, int extra_perm);
1da177e4 182
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183static inline void ipc_update_pid(struct pid **pos, struct pid *pid)
184{
185 struct pid *old = *pos;
186 if (old != pid) {
187 *pos = get_pid(pid);
188 put_pid(old);
189 }
190}
191
275f2214 192#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
239521f3 193int ipc_parse_version(int *cmd);
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194#endif
195
196extern void free_msg(struct msg_msg *msg);
4e9b45a1 197extern struct msg_msg *load_msg(const void __user *src, size_t len);
4a674f34 198extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
4e9b45a1 199extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
7748dbfa 200
27c331a1 201static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id)
023a5355 202{
27c331a1 203 return ipcid_to_seqx(id) != ipcp->seq;
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ND
204}
205
1ca7003a 206static inline void ipc_lock_object(struct kern_ipc_perm *perm)
023a5355 207{
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208 spin_lock(&perm->lock);
209}
210
1ca7003a 211static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
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ND
212{
213 spin_unlock(&perm->lock);
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214}
215
1ca7003a 216static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
16df3674 217{
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218 assert_spin_locked(&perm->lock);
219}
220
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221static inline void ipc_unlock(struct kern_ipc_perm *perm)
222{
cf9d5d78 223 ipc_unlock_object(perm);
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224 rcu_read_unlock();
225}
226
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227/*
228 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
229 * where the respective ipc_ids.rwsem is not being held down.
230 * Checks whether the ipc object is still around or if it's gone already, as
231 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
232 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
233 * checkpoint case at sys_semtimedop() as noted in code commentary.
234 */
235static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
236{
72a8ff2f 237 return !perm->deleted;
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RA
238}
239
4d2bff5e 240struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
b2d75cdd 241int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
eb66ec44 242 const struct ipc_ops *ops, struct ipc_params *params);
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243void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
244 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
553f770e 245
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246static inline int sem_check_semmni(struct ipc_namespace *ns) {
247 /*
5ac893b8 248 * Check semmni range [0, ipc_mni]
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249 * semmni is the last element of sem_ctls[4] array
250 */
5ac893b8 251 return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > ipc_mni))
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252 ? -ERANGE : 0;
253}
254
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AV
255#ifdef CONFIG_COMPAT
256#include <linux/compat.h>
257struct compat_ipc_perm {
258 key_t key;
259 __compat_uid_t uid;
260 __compat_gid_t gid;
261 __compat_uid_t cuid;
262 __compat_gid_t cgid;
263 compat_mode_t mode;
264 unsigned short seq;
265};
266
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267void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *);
268void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *);
269int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *);
270int get_compat_ipc64_perm(struct ipc64_perm *,
271 struct compat_ipc64_perm __user *);
272
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273static inline int compat_ipc_parse_version(int *cmd)
274{
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275 int version = *cmd & IPC_64;
276 *cmd &= ~IPC_64;
277 return version;
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278}
279#endif
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280
281/* for __ARCH_WANT_SYS_IPC */
282long ksys_semtimedop(int semid, struct sembuf __user *tsops,
283 unsigned int nsops,
21fc538d 284 const struct __kernel_timespec __user *timeout);
69894718 285long ksys_semget(key_t key, int nsems, int semflg);
275f2214 286long ksys_old_semctl(int semid, int semnum, int cmd, unsigned long arg);
3d65661a 287long ksys_msgget(key_t key, int msgflg);
275f2214 288long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);
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289long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
290 long msgtyp, int msgflg);
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291long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
292 int msgflg);
65749e0b 293long ksys_shmget(key_t key, size_t size, int shmflg);
da1e2744 294long ksys_shmdt(char __user *shmaddr);
275f2214 295long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf);
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296
297/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */
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298long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
299 unsigned int nsops,
9afc5eee 300 const struct old_timespec32 __user *timeout);
b0d17578 301#ifdef CONFIG_COMPAT
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AB
302long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg);
303long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr);
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304long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
305 compat_long_t msgtyp, int msgflg);
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306long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
307 compat_ssize_t msgsz, int msgflg);
275f2214 308long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr);
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DB
309#endif /* CONFIG_COMPAT */
310
1da177e4 311#endif