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 | /* |
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 |
30 | #define IPCMNI_EXTEND_MIN_CYCLE (RADIX_TREE_MAP_SIZE * RADIX_TREE_MAP_SIZE) |
31 | #define IPCMNI (1 << IPCMNI_SHIFT) |
32 | #define IPCMNI_EXTEND (1 << IPCMNI_EXTEND_SHIFT) |
33 | |
34 | #ifdef CONFIG_SYSVIPC_SYSCTL |
35 | extern int ipc_mni; |
36 | extern int ipc_mni_shift; |
37 | extern int ipc_min_cycle; |
38 | |
39 | #define ipcmni_seq_shift() ipc_mni_shift |
40 | #define IPCMNI_IDX_MASK ((1 << ipc_mni_shift) - 1) |
41 | |
42 | #else /* CONFIG_SYSVIPC_SYSCTL */ |
43 | |
44 | #define ipc_mni IPCMNI |
45 | #define ipc_min_cycle ((int)RADIX_TREE_MAP_SIZE) |
46 | #define ipcmni_seq_shift() IPCMNI_SHIFT |
47 | #define IPCMNI_IDX_MASK ((1 << IPCMNI_SHIFT) - 1) |
48 | #endif /* CONFIG_SYSVIPC_SYSCTL */ |
49 | |
50 | void sem_init(void); |
51 | void msg_init(void); |
52 | void shm_init(void); |
53 | |
54 | struct ipc_namespace; |
55 | struct pid_namespace; |
56 | |
57 | #ifdef CONFIG_POSIX_MQUEUE |
58 | extern void mq_clear_sbinfo(struct ipc_namespace *ns); |
59 | #else |
60 | static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { } |
61 | #endif |
62 | |
63 | #ifdef CONFIG_SYSVIPC |
64 | void sem_init_ns(struct ipc_namespace *ns); |
65 | int msg_init_ns(struct ipc_namespace *ns); |
66 | void shm_init_ns(struct ipc_namespace *ns); |
67 | |
68 | void sem_exit_ns(struct ipc_namespace *ns); |
69 | void msg_exit_ns(struct ipc_namespace *ns); |
70 | void shm_exit_ns(struct ipc_namespace *ns); |
71 | #else |
72 | static inline void sem_init_ns(struct ipc_namespace *ns) { } |
73 | static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; } |
74 | static inline void shm_init_ns(struct ipc_namespace *ns) { } |
75 | |
76 | static inline void sem_exit_ns(struct ipc_namespace *ns) { } |
77 | static inline void msg_exit_ns(struct ipc_namespace *ns) { } |
78 | static inline void shm_exit_ns(struct ipc_namespace *ns) { } |
79 | #endif |
80 | |
81 | /* |
82 | * Structure that holds the parameters needed by the ipc operations |
83 | * (see after) |
84 | */ |
85 | struct ipc_params { |
86 | key_t key; |
87 | int flg; |
88 | union { |
89 | size_t size; /* for shared memories */ |
90 | int nsems; /* for semaphores */ |
91 | } u; /* holds the getnew() specific param */ |
92 | }; |
93 | |
94 | /* |
95 | * Structure that holds some ipc operations. This structure is used to unify |
96 | * the calls to sys_msgget(), sys_semget(), sys_shmget() |
97 | * . routine to call to create a new ipc object. Can be one of newque, |
98 | * newary, newseg |
99 | * . routine to call to check permissions for a new ipc object. |
100 | * Can be one of security_msg_associate, security_sem_associate, |
101 | * security_shm_associate |
102 | * . routine to call for an extra check if needed |
103 | */ |
104 | struct ipc_ops { |
105 | int (*getnew)(struct ipc_namespace *, struct ipc_params *); |
106 | int (*associate)(struct kern_ipc_perm *, int); |
107 | int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *); |
108 | }; |
109 | |
110 | struct seq_file; |
111 | struct ipc_ids; |
112 | |
113 | void ipc_init_ids(struct ipc_ids *ids); |
114 | #ifdef CONFIG_PROC_FS |
115 | void __init ipc_init_proc_interface(const char *path, const char *, |
116 | int ids, int (*show)(struct seq_file *, void *)); |
117 | struct pid_namespace *ipc_seq_pid_ns(struct seq_file *); |
118 | #else |
119 | #define ipc_init_proc_interface(path, header, ids, show) do {} while (0) |
120 | #endif |
121 | |
122 | #define IPC_SEM_IDS 0 |
123 | #define IPC_MSG_IDS 1 |
124 | #define IPC_SHM_IDS 2 |
125 | |
126 | #define ipcid_to_idx(id) ((id) & IPCMNI_IDX_MASK) |
127 | #define ipcid_to_seqx(id) ((id) >> ipcmni_seq_shift()) |
128 | #define ipcid_seq_max() (INT_MAX >> ipcmni_seq_shift()) |
129 | |
130 | /* must be called with ids->rwsem acquired for writing */ |
131 | int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); |
132 | |
133 | /* must be called with both locks acquired. */ |
134 | void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); |
135 | |
136 | /* must be called with both locks acquired. */ |
137 | void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *); |
138 | |
139 | /* must be called with ipcp locked */ |
140 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg); |
141 | |
142 | /** |
143 | * ipc_get_maxidx - get the highest assigned index |
144 | * @ids: ipc identifier set |
145 | * |
146 | * The function returns the highest assigned index for @ids. The function |
147 | * doesn't scan the idr tree, it uses a cached value. |
148 | * |
149 | * Called with ipc_ids.rwsem held for reading. |
150 | */ |
151 | static inline int ipc_get_maxidx(struct ipc_ids *ids) |
152 | { |
153 | if (ids->in_use == 0) |
154 | return -1; |
155 | |
156 | if (ids->in_use == ipc_mni) |
157 | return ipc_mni - 1; |
158 | |
159 | return ids->max_idx; |
160 | } |
161 | |
162 | /* |
163 | * For allocation that need to be freed by RCU. |
164 | * Objects are reference counted, they start with reference count 1. |
165 | * getref increases the refcount, the putref call that reduces the recount |
166 | * to 0 schedules the rcu destruction. Caller must guarantee locking. |
167 | * |
168 | * refcount is initialized by ipc_addid(), before that point call_rcu() |
169 | * must be used. |
170 | */ |
171 | bool ipc_rcu_getref(struct kern_ipc_perm *ptr); |
172 | void ipc_rcu_putref(struct kern_ipc_perm *ptr, |
173 | void (*func)(struct rcu_head *head)); |
174 | |
175 | struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id); |
176 | |
177 | void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); |
178 | void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); |
179 | int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); |
180 | struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns, |
181 | struct ipc_ids *ids, int id, int cmd, |
182 | struct ipc64_perm *perm, int ); |
183 | |
184 | static inline void ipc_update_pid(struct pid **pos, struct pid *pid) |
185 | { |
186 | struct pid *old = *pos; |
187 | if (old != pid) { |
188 | *pos = get_pid(pid); |
189 | put_pid(pid: old); |
190 | } |
191 | } |
192 | |
193 | #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
194 | int ipc_parse_version(int *cmd); |
195 | #endif |
196 | |
197 | extern void free_msg(struct msg_msg *msg); |
198 | extern struct msg_msg *load_msg(const void __user *src, size_t len); |
199 | extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); |
200 | extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len); |
201 | |
202 | static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id) |
203 | { |
204 | return ipcid_to_seqx(id) != ipcp->seq; |
205 | } |
206 | |
207 | static inline void ipc_lock_object(struct kern_ipc_perm *perm) |
208 | { |
209 | spin_lock(lock: &perm->lock); |
210 | } |
211 | |
212 | static inline void ipc_unlock_object(struct kern_ipc_perm *perm) |
213 | { |
214 | spin_unlock(lock: &perm->lock); |
215 | } |
216 | |
217 | static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm) |
218 | { |
219 | assert_spin_locked(&perm->lock); |
220 | } |
221 | |
222 | static inline void ipc_unlock(struct kern_ipc_perm *perm) |
223 | { |
224 | ipc_unlock_object(perm); |
225 | rcu_read_unlock(); |
226 | } |
227 | |
228 | /* |
229 | * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths |
230 | * where the respective ipc_ids.rwsem is not being held down. |
231 | * Checks whether the ipc object is still around or if it's gone already, as |
232 | * ipc_rmid() may have already freed the ID while the ipc lock was spinning. |
233 | * Needs to be called with kern_ipc_perm.lock held -- exception made for one |
234 | * checkpoint case at sys_semtimedop() as noted in code commentary. |
235 | */ |
236 | static inline bool ipc_valid_object(struct kern_ipc_perm *perm) |
237 | { |
238 | return !perm->deleted; |
239 | } |
240 | |
241 | struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id); |
242 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, |
243 | const struct ipc_ops *ops, struct ipc_params *params); |
244 | void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, |
245 | void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); |
246 | |
247 | static inline int sem_check_semmni(struct ipc_namespace *ns) { |
248 | /* |
249 | * Check semmni range [0, ipc_mni] |
250 | * semmni is the last element of sem_ctls[4] array |
251 | */ |
252 | return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > ipc_mni)) |
253 | ? -ERANGE : 0; |
254 | } |
255 | |
256 | #ifdef CONFIG_COMPAT |
257 | #include <linux/compat.h> |
258 | struct compat_ipc_perm { |
259 | key_t key; |
260 | __compat_uid_t uid; |
261 | __compat_gid_t gid; |
262 | __compat_uid_t cuid; |
263 | __compat_gid_t cgid; |
264 | compat_mode_t mode; |
265 | unsigned short seq; |
266 | }; |
267 | |
268 | void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *); |
269 | void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *); |
270 | int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *); |
271 | int get_compat_ipc64_perm(struct ipc64_perm *, |
272 | struct compat_ipc64_perm __user *); |
273 | |
274 | static inline int compat_ipc_parse_version(int *cmd) |
275 | { |
276 | int version = *cmd & IPC_64; |
277 | *cmd &= ~IPC_64; |
278 | return version; |
279 | } |
280 | |
281 | long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg); |
282 | long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr); |
283 | long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, |
284 | compat_long_t msgtyp, int msgflg); |
285 | long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp, |
286 | compat_ssize_t msgsz, int msgflg); |
287 | long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr); |
288 | |
289 | #endif |
290 | |
291 | #endif |
292 | |