| 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 *header, |
| 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 extra_perm); |
| 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(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(&perm->lock); |
| 210 | } |
| 211 | |
| 212 | static inline void ipc_unlock_object(struct kern_ipc_perm *perm) |
| 213 | { |
| 214 | spin_unlock(&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 |