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 int sem_init(void); 22 int 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 int sem_init_ns(struct ipc_namespace *ns); 38 int msg_init_ns(struct ipc_namespace *ns); 39 int 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 int sem_init_ns(struct ipc_namespace *ns) { return 0; } 46 static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; } 47 static inline int shm_init_ns(struct ipc_namespace *ns) { return 0; } 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 int ipc_init_ids(struct ipc_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_maxid - get the last assigned id 117 * @ids: ipc identifier set 118 * 119 * Called with ipc_ids.rwsem held for reading. 120 */ 121 static inline int ipc_get_maxid(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_id; 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 int 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_lock(struct ipc_ids *, int); 146 struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id); 147 148 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); 149 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); 150 int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); 151 struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, 152 struct ipc_ids *ids, int id, int cmd, 153 struct ipc64_perm *perm, int extra_perm); 154 155 static inline void ipc_update_pid(struct pid **pos, struct pid *pid) 156 { 157 struct pid *old = *pos; 158 if (old != pid) { 159 *pos = get_pid(pid); 160 put_pid(old); 161 } 162 } 163 164 #ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION 165 /* On IA-64, we always use the "64-bit version" of the IPC structures. */ 166 # define ipc_parse_version(cmd) IPC_64 167 #else 168 int ipc_parse_version(int *cmd); 169 #endif 170 171 extern void free_msg(struct msg_msg *msg); 172 extern struct msg_msg *load_msg(const void __user *src, size_t len); 173 extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); 174 extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len); 175 176 static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) 177 { 178 return uid / SEQ_MULTIPLIER != ipcp->seq; 179 } 180 181 static inline void ipc_lock_object(struct kern_ipc_perm *perm) 182 { 183 spin_lock(&perm->lock); 184 } 185 186 static inline void ipc_unlock_object(struct kern_ipc_perm *perm) 187 { 188 spin_unlock(&perm->lock); 189 } 190 191 static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm) 192 { 193 assert_spin_locked(&perm->lock); 194 } 195 196 static inline void ipc_unlock(struct kern_ipc_perm *perm) 197 { 198 ipc_unlock_object(perm); 199 rcu_read_unlock(); 200 } 201 202 /* 203 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths 204 * where the respective ipc_ids.rwsem is not being held down. 205 * Checks whether the ipc object is still around or if it's gone already, as 206 * ipc_rmid() may have already freed the ID while the ipc lock was spinning. 207 * Needs to be called with kern_ipc_perm.lock held -- exception made for one 208 * checkpoint case at sys_semtimedop() as noted in code commentary. 209 */ 210 static inline bool ipc_valid_object(struct kern_ipc_perm *perm) 211 { 212 return !perm->deleted; 213 } 214 215 struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id); 216 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, 217 const struct ipc_ops *ops, struct ipc_params *params); 218 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, 219 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); 220 221 #ifdef CONFIG_COMPAT 222 #include <linux/compat.h> 223 struct compat_ipc_perm { 224 key_t key; 225 __compat_uid_t uid; 226 __compat_gid_t gid; 227 __compat_uid_t cuid; 228 __compat_gid_t cgid; 229 compat_mode_t mode; 230 unsigned short seq; 231 }; 232 233 void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *); 234 void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *); 235 int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *); 236 int get_compat_ipc64_perm(struct ipc64_perm *, 237 struct compat_ipc64_perm __user *); 238 239 static inline int compat_ipc_parse_version(int *cmd) 240 { 241 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION 242 int version = *cmd & IPC_64; 243 *cmd &= ~IPC_64; 244 return version; 245 #else 246 return IPC_64; 247 #endif 248 } 249 #endif 250 251 /* for __ARCH_WANT_SYS_IPC */ 252 long ksys_semtimedop(int semid, struct sembuf __user *tsops, 253 unsigned int nsops, 254 const struct __kernel_timespec __user *timeout); 255 long ksys_semget(key_t key, int nsems, int semflg); 256 long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg); 257 long ksys_msgget(key_t key, int msgflg); 258 long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf); 259 long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, 260 long msgtyp, int msgflg); 261 long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, 262 int msgflg); 263 long ksys_shmget(key_t key, size_t size, int shmflg); 264 long ksys_shmdt(char __user *shmaddr); 265 long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf); 266 267 /* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */ 268 long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems, 269 unsigned int nsops, 270 const struct compat_timespec __user *timeout); 271 #ifdef CONFIG_COMPAT 272 long compat_ksys_semctl(int semid, int semnum, int cmd, int arg); 273 long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr); 274 long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, 275 compat_long_t msgtyp, int msgflg); 276 long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp, 277 compat_ssize_t msgsz, int msgflg); 278 long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr); 279 #endif /* CONFIG_COMPAT */ 280 281 #endif 282