1 /* SPDX-License-Identifier: GPL-2.0 */
4 * Copyright (C) 1999 Christoph Rohland
6 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
7 * namespaces support. 2006 OpenVZ, SWsoft Inc.
8 * Pavel Emelianov <xemul@openvz.org>
14 #include <linux/unistd.h>
15 #include <linux/err.h>
16 #include <linux/ipc_namespace.h>
19 * The IPC ID contains 2 separate numbers - index and sequence number.
21 * bits 0-14: index (32k, 15 bits)
22 * bits 15-30: sequence number (64k, 16 bits)
24 * When IPCMNI extension mode is turned on, the composition changes:
25 * bits 0-22: index (8M, 23 bits)
26 * bits 23-30: sequence number (256, 8 bits)
28 #define IPCMNI_SHIFT 15
29 #define IPCMNI_EXTEND_SHIFT 23
30 #define IPCMNI (1 << IPCMNI_SHIFT)
31 #define IPCMNI_EXTEND (1 << IPCMNI_EXTEND_SHIFT)
33 #ifdef CONFIG_SYSVIPC_SYSCTL
35 extern int ipc_mni_shift;
36 extern bool ipc_mni_extended;
38 #define IPCMNI_SEQ_SHIFT ipc_mni_shift
39 #define IPCMNI_IDX_MASK ((1 << ipc_mni_shift) - 1)
41 #else /* CONFIG_SYSVIPC_SYSCTL */
43 #define ipc_mni IPCMNI
44 #define ipc_mni_extended false
45 #define IPCMNI_SEQ_SHIFT IPCMNI_SHIFT
46 #define IPCMNI_IDX_MASK ((1 << IPCMNI_SHIFT) - 1)
47 #endif /* CONFIG_SYSVIPC_SYSCTL */
56 #ifdef CONFIG_POSIX_MQUEUE
57 extern void mq_clear_sbinfo(struct ipc_namespace *ns);
58 extern void mq_put_mnt(struct ipc_namespace *ns);
60 static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
61 static inline void mq_put_mnt(struct ipc_namespace *ns) { }
65 void sem_init_ns(struct ipc_namespace *ns);
66 void msg_init_ns(struct ipc_namespace *ns);
67 void shm_init_ns(struct ipc_namespace *ns);
69 void sem_exit_ns(struct ipc_namespace *ns);
70 void msg_exit_ns(struct ipc_namespace *ns);
71 void shm_exit_ns(struct ipc_namespace *ns);
73 static inline void sem_init_ns(struct ipc_namespace *ns) { }
74 static inline void msg_init_ns(struct ipc_namespace *ns) { }
75 static inline void shm_init_ns(struct ipc_namespace *ns) { }
77 static inline void sem_exit_ns(struct ipc_namespace *ns) { }
78 static inline void msg_exit_ns(struct ipc_namespace *ns) { }
79 static inline void shm_exit_ns(struct ipc_namespace *ns) { }
83 * Structure that holds the parameters needed by the ipc operations
90 size_t size; /* for shared memories */
91 int nsems; /* for semaphores */
92 } u; /* holds the getnew() specific param */
96 * Structure that holds some ipc operations. This structure is used to unify
97 * the calls to sys_msgget(), sys_semget(), sys_shmget()
98 * . routine to call to create a new ipc object. Can be one of newque,
100 * . routine to call to check permissions for a new ipc object.
101 * Can be one of security_msg_associate, security_sem_associate,
102 * security_shm_associate
103 * . routine to call for an extra check if needed
106 int (*getnew)(struct ipc_namespace *, struct ipc_params *);
107 int (*associate)(struct kern_ipc_perm *, int);
108 int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *);
114 void ipc_init_ids(struct ipc_ids *ids);
115 #ifdef CONFIG_PROC_FS
116 void __init ipc_init_proc_interface(const char *path, const char *header,
117 int ids, int (*show)(struct seq_file *, void *));
118 struct pid_namespace *ipc_seq_pid_ns(struct seq_file *);
120 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
123 #define IPC_SEM_IDS 0
124 #define IPC_MSG_IDS 1
125 #define IPC_SHM_IDS 2
127 #define ipcid_to_idx(id) ((id) & IPCMNI_IDX_MASK)
128 #define ipcid_to_seqx(id) ((id) >> IPCMNI_SEQ_SHIFT)
129 #define IPCID_SEQ_MAX (INT_MAX >> IPCMNI_SEQ_SHIFT)
131 /* must be called with ids->rwsem acquired for writing */
132 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
134 /* must be called with both locks acquired. */
135 void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
137 /* must be called with both locks acquired. */
138 void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
140 /* must be called with ipcp locked */
141 int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
144 * ipc_get_maxidx - get the highest assigned index
145 * @ids: ipc identifier set
147 * Called with ipc_ids.rwsem held for reading.
149 static inline int ipc_get_maxidx(struct ipc_ids *ids)
151 if (ids->in_use == 0)
154 if (ids->in_use == ipc_mni)
161 * For allocation that need to be freed by RCU.
162 * Objects are reference counted, they start with reference count 1.
163 * getref increases the refcount, the putref call that reduces the recount
164 * to 0 schedules the rcu destruction. Caller must guarantee locking.
166 * refcount is initialized by ipc_addid(), before that point call_rcu()
169 bool ipc_rcu_getref(struct kern_ipc_perm *ptr);
170 void ipc_rcu_putref(struct kern_ipc_perm *ptr,
171 void (*func)(struct rcu_head *head));
173 struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
175 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
176 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
177 int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
178 struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
179 struct ipc_ids *ids, int id, int cmd,
180 struct ipc64_perm *perm, int extra_perm);
182 static inline void ipc_update_pid(struct pid **pos, struct pid *pid)
184 struct pid *old = *pos;
191 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
192 int ipc_parse_version(int *cmd);
195 extern void free_msg(struct msg_msg *msg);
196 extern struct msg_msg *load_msg(const void __user *src, size_t len);
197 extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
198 extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
200 static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id)
202 return ipcid_to_seqx(id) != ipcp->seq;
205 static inline void ipc_lock_object(struct kern_ipc_perm *perm)
207 spin_lock(&perm->lock);
210 static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
212 spin_unlock(&perm->lock);
215 static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
217 assert_spin_locked(&perm->lock);
220 static inline void ipc_unlock(struct kern_ipc_perm *perm)
222 ipc_unlock_object(perm);
227 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
228 * where the respective ipc_ids.rwsem is not being held down.
229 * Checks whether the ipc object is still around or if it's gone already, as
230 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
231 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
232 * checkpoint case at sys_semtimedop() as noted in code commentary.
234 static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
236 return !perm->deleted;
239 struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
240 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
241 const struct ipc_ops *ops, struct ipc_params *params);
242 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
243 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
245 static inline int sem_check_semmni(struct ipc_namespace *ns) {
247 * Check semmni range [0, ipc_mni]
248 * semmni is the last element of sem_ctls[4] array
250 return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > ipc_mni))
255 #include <linux/compat.h>
256 struct compat_ipc_perm {
266 void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *);
267 void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *);
268 int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *);
269 int get_compat_ipc64_perm(struct ipc64_perm *,
270 struct compat_ipc64_perm __user *);
272 static inline int compat_ipc_parse_version(int *cmd)
274 int version = *cmd & IPC_64;
280 /* for __ARCH_WANT_SYS_IPC */
281 long ksys_semtimedop(int semid, struct sembuf __user *tsops,
283 const struct __kernel_timespec __user *timeout);
284 long ksys_semget(key_t key, int nsems, int semflg);
285 long ksys_old_semctl(int semid, int semnum, int cmd, unsigned long arg);
286 long ksys_msgget(key_t key, int msgflg);
287 long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);
288 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
289 long msgtyp, int msgflg);
290 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
292 long ksys_shmget(key_t key, size_t size, int shmflg);
293 long ksys_shmdt(char __user *shmaddr);
294 long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf);
296 /* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */
297 long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
299 const struct old_timespec32 __user *timeout);
301 long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg);
302 long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr);
303 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
304 compat_long_t msgtyp, int msgflg);
305 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
306 compat_ssize_t msgsz, int msgflg);
307 long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr);
308 #endif /* CONFIG_COMPAT */