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 32 static inline void mq_clear_sbinfo(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 45 static inline void sem_init_ns(struct ipc_namespace *ns) { } 46 static inline void msg_init_ns(struct ipc_namespace *ns) { } 47 static inline void shm_init_ns(struct ipc_namespace *ns) { } 48 49 static inline void sem_exit_ns(struct ipc_namespace *ns) { } 50 static inline void msg_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 */ 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); 153 154 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); 174 175 static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id) 176 { 177 return ipcid_to_seqx(id) != ipcp->seq; 178 } 179 180 static inline void ipc_lock_object(struct kern_ipc_perm *perm) 181 { 182 spin_lock(&perm->lock); 183 } 184 185 static inline void ipc_unlock_object(struct kern_ipc_perm *perm) 186 { 187 spin_unlock(&perm->lock); 188 } 189 190 static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm) 191 { 192 assert_spin_locked(&perm->lock); 193 } 194 195 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 */ 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 static inline int sem_check_semmni(struct ipc_namespace *ns) { 221 /* 222 * Check semmni range [0, IPCMNI] 223 * semmni is the last element of sem_ctls[4] array 224 */ 225 return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > IPCMNI)) 226 ? -ERANGE : 0; 227 } 228 229 #ifdef CONFIG_COMPAT 230 #include <linux/compat.h> 231 struct compat_ipc_perm { 232 key_t key; 233 __compat_uid_t uid; 234 __compat_gid_t gid; 235 __compat_uid_t cuid; 236 __compat_gid_t cgid; 237 compat_mode_t mode; 238 unsigned short seq; 239 }; 240 241 void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *); 242 void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *); 243 int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *); 244 int get_compat_ipc64_perm(struct ipc64_perm *, 245 struct compat_ipc64_perm __user *); 246 247 static inline int compat_ipc_parse_version(int *cmd) 248 { 249 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION 250 int version = *cmd & IPC_64; 251 *cmd &= ~IPC_64; 252 return version; 253 #else 254 return IPC_64; 255 #endif 256 } 257 #endif 258 259 /* for __ARCH_WANT_SYS_IPC */ 260 long ksys_semtimedop(int semid, struct sembuf __user *tsops, 261 unsigned int nsops, 262 const struct __kernel_timespec __user *timeout); 263 long ksys_semget(key_t key, int nsems, int semflg); 264 long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg); 265 long ksys_msgget(key_t key, int msgflg); 266 long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf); 267 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, 268 long msgtyp, int msgflg); 269 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, 270 int msgflg); 271 long ksys_shmget(key_t key, size_t size, int shmflg); 272 long ksys_shmdt(char __user *shmaddr); 273 long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf); 274 275 /* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */ 276 long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems, 277 unsigned int nsops, 278 const struct old_timespec32 __user *timeout); 279 #ifdef CONFIG_COMPAT 280 long compat_ksys_semctl(int semid, int semnum, int cmd, int arg); 281 long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr); 282 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, 283 compat_long_t msgtyp, int msgflg); 284 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp, 285 compat_ssize_t msgsz, int msgflg); 286 long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr); 287 #endif /* CONFIG_COMPAT */ 288 289 #endif 290