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#include <linux/pid.h> 18 19/* 20 * The IPC ID contains 2 separate numbers - index and sequence number. 21 * By default, 22 * bits 0-14: index (32k, 15 bits) 23 * bits 15-30: sequence number (64k, 16 bits) 24 * 25 * When IPCMNI extension mode is turned on, the composition changes: 26 * bits 0-23: index (16M, 24 bits) 27 * bits 24-30: sequence number (128, 7 bits) 28 */ 29#define IPCMNI_SHIFT 15 30#define IPCMNI_EXTEND_SHIFT 24 31#define IPCMNI_EXTEND_MIN_CYCLE (RADIX_TREE_MAP_SIZE * RADIX_TREE_MAP_SIZE) 32#define IPCMNI (1 << IPCMNI_SHIFT) 33#define IPCMNI_EXTEND (1 << IPCMNI_EXTEND_SHIFT) 34 35#ifdef CONFIG_SYSVIPC_SYSCTL 36extern int ipc_mni; 37extern int ipc_mni_shift; 38extern int ipc_min_cycle; 39 40#define ipcmni_seq_shift() ipc_mni_shift 41#define IPCMNI_IDX_MASK ((1 << ipc_mni_shift) - 1) 42 43#else /* CONFIG_SYSVIPC_SYSCTL */ 44 45#define ipc_mni IPCMNI 46#define ipc_min_cycle ((int)RADIX_TREE_MAP_SIZE) 47#define ipcmni_seq_shift() IPCMNI_SHIFT 48#define IPCMNI_IDX_MASK ((1 << IPCMNI_SHIFT) - 1) 49#endif /* CONFIG_SYSVIPC_SYSCTL */ 50 51void sem_init(void); 52void msg_init(void); 53void shm_init(void); 54 55struct ipc_namespace; 56struct pid_namespace; 57 58#ifdef CONFIG_POSIX_MQUEUE 59extern void mq_clear_sbinfo(struct ipc_namespace *ns); 60#else 61static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { } 62#endif 63 64#ifdef CONFIG_SYSVIPC 65void sem_init_ns(struct ipc_namespace *ns); 66int msg_init_ns(struct ipc_namespace *ns); 67void shm_init_ns(struct ipc_namespace *ns); 68 69void sem_exit_ns(struct ipc_namespace *ns); 70void msg_exit_ns(struct ipc_namespace *ns); 71void shm_exit_ns(struct ipc_namespace *ns); 72#else 73static inline void sem_init_ns(struct ipc_namespace *ns) { } 74static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; } 75static inline void shm_init_ns(struct ipc_namespace *ns) { } 76 77static inline void sem_exit_ns(struct ipc_namespace *ns) { } 78static inline void msg_exit_ns(struct ipc_namespace *ns) { } 79static inline void shm_exit_ns(struct ipc_namespace *ns) { } 80#endif 81 82/* 83 * Structure that holds the parameters needed by the ipc operations 84 * (see after) 85 */ 86struct ipc_params { 87 key_t key; 88 int flg; 89 union { 90 size_t size; /* for shared memories */ 91 int nsems; /* for semaphores */ 92 } u; /* holds the getnew() specific param */ 93}; 94 95/* 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, 99 * newary, newseg 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 104 */ 105struct ipc_ops { 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 *); 109}; 110 111struct seq_file; 112struct ipc_ids; 113 114void ipc_init_ids(struct ipc_ids *ids); 115#ifdef CONFIG_PROC_FS 116void __init ipc_init_proc_interface(const char *path, const char *header, 117 int ids, int (*show)(struct seq_file *, void *)); 118struct pid_namespace *ipc_seq_pid_ns(struct seq_file *); 119#else 120#define ipc_init_proc_interface(path, header, ids, show) do {} while (0) 121#endif 122 123#define IPC_SEM_IDS 0 124#define IPC_MSG_IDS 1 125#define IPC_SHM_IDS 2 126 127#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()) 130 131/* must be called with ids->rwsem acquired for writing */ 132int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); 133 134/* must be called with both locks acquired. */ 135void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); 136 137/* must be called with both locks acquired. */ 138void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *); 139 140/* must be called with ipcp locked */ 141int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg); 142 143/** 144 * ipc_get_maxidx - get the highest assigned index 145 * @ids: ipc identifier set 146 * 147 * The function returns the highest assigned index for @ids. The function 148 * doesn't scan the idr tree, it uses a cached value. 149 * 150 * Called with ipc_ids.rwsem held for reading. 151 */ 152static inline int ipc_get_maxidx(struct ipc_ids *ids) 153{ 154 if (ids->in_use == 0) 155 return -1; 156 157 if (ids->in_use == ipc_mni) 158 return ipc_mni - 1; 159 160 return ids->max_idx; 161} 162 163/* 164 * For allocation that need to be freed by RCU. 165 * Objects are reference counted, they start with reference count 1. 166 * getref increases the refcount, the putref call that reduces the recount 167 * to 0 schedules the rcu destruction. Caller must guarantee locking. 168 * 169 * refcount is initialized by ipc_addid(), before that point call_rcu() 170 * must be used. 171 */ 172bool ipc_rcu_getref(struct kern_ipc_perm *ptr); 173void ipc_rcu_putref(struct kern_ipc_perm *ptr, 174 void (*func)(struct rcu_head *head)); 175 176struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id); 177 178void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); 179void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); 180int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); 181struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns, 182 struct ipc_ids *ids, int id, int cmd, 183 struct ipc64_perm *perm, int extra_perm); 184 185static inline void ipc_update_pid(struct pid **pos, struct pid *pid) 186{ 187 struct pid *old = *pos; 188 if (old != pid) { 189 *pos = get_pid(pid); 190 put_pid(old); 191 } 192} 193 194#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION 195int ipc_parse_version(int *cmd); 196#endif 197 198extern void free_msg(struct msg_msg *msg); 199extern struct msg_msg *load_msg(const void __user *src, size_t len); 200extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); 201extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len); 202 203static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id) 204{ 205 return ipcid_to_seqx(id) != ipcp->seq; 206} 207 208static inline void ipc_lock_object(struct kern_ipc_perm *perm) 209{ 210 spin_lock(&perm->lock); 211} 212 213static inline void ipc_unlock_object(struct kern_ipc_perm *perm) 214{ 215 spin_unlock(&perm->lock); 216} 217 218static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm) 219{ 220 assert_spin_locked(&perm->lock); 221} 222 223static inline void ipc_unlock(struct kern_ipc_perm *perm) 224{ 225 ipc_unlock_object(perm); 226 rcu_read_unlock(); 227} 228 229/* 230 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths 231 * where the respective ipc_ids.rwsem is not being held down. 232 * Checks whether the ipc object is still around or if it's gone already, as 233 * ipc_rmid() may have already freed the ID while the ipc lock was spinning. 234 * Needs to be called with kern_ipc_perm.lock held -- exception made for one 235 * checkpoint case at sys_semtimedop() as noted in code commentary. 236 */ 237static inline bool ipc_valid_object(struct kern_ipc_perm *perm) 238{ 239 return !perm->deleted; 240} 241 242struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id); 243int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, 244 const struct ipc_ops *ops, struct ipc_params *params); 245void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, 246 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); 247 248static inline int sem_check_semmni(struct ipc_namespace *ns) { 249 /* 250 * Check semmni range [0, ipc_mni] 251 * semmni is the last element of sem_ctls[4] array 252 */ 253 return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > ipc_mni)) 254 ? -ERANGE : 0; 255} 256 257#ifdef CONFIG_COMPAT 258#include <linux/compat.h> 259struct compat_ipc_perm { 260 key_t key; 261 __compat_uid_t uid; 262 __compat_gid_t gid; 263 __compat_uid_t cuid; 264 __compat_gid_t cgid; 265 compat_mode_t mode; 266 unsigned short seq; 267}; 268 269void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *); 270void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *); 271int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *); 272int get_compat_ipc64_perm(struct ipc64_perm *, 273 struct compat_ipc64_perm __user *); 274 275static inline int compat_ipc_parse_version(int *cmd) 276{ 277 int version = *cmd & IPC_64; 278 *cmd &= ~IPC_64; 279 return version; 280} 281 282long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg); 283long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr); 284long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, 285 compat_long_t msgtyp, int msgflg); 286long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp, 287 compat_ssize_t msgsz, int msgflg); 288long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr); 289 290#endif 291 292#endif 293