| 1 | |
| 2 | * linux/ipc/util.c
|
| 3 | * Copyright (C) 1992 Krishna Balasubramanian
|
| 4 | *
|
| 5 | * Sep 1997 - Call suser() last after "normal" permission checks so we
|
| 6 | * get BSD style process accounting right.
|
| 7 | * Occurs in several places in the IPC code.
|
| 8 | * Chris Evans, <[email protected]>
|
| 9 | * Nov 1999 - ipc helper functions, unified SMP locking
|
| 10 | * Manfred Spraul <[email protected]>
|
| 11 | * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
|
| 12 | * Mingming Cao <[email protected]>
|
| 13 | * Mar 2006 - support for audit of ipc object properties
|
| 14 | * Dustin Kirkland <[email protected]>
|
| 15 | * Jun 2006 - namespaces ssupport
|
| 16 | * OpenVZ, SWsoft Inc.
|
| 17 | * Pavel Emelianov <[email protected]>
|
| 18 |
|
| 19 |
|
| 20 | #include <linux/mm.h>
|
| 21 | #include <linux/shm.h>
|
| 22 | #include <linux/init.h>
|
| 23 | #include <linux/msg.h>
|
| 24 | #include <linux/vmalloc.h>
|
| 25 | #include <linux/slab.h>
|
| 26 | #include <linux/capability.h>
|
| 27 | #include <linux/highuid.h>
|
| 28 | #include <linux/security.h>
|
| 29 | #include <linux/rcupdate.h>
|
| 30 | #include <linux/workqueue.h>
|
| 31 | #include <linux/seq_file.h>
|
| 32 | #include <linux/proc_fs.h>
|
| 33 | #include <linux/audit.h>
|
| 34 | #include <linux/nsproxy.h>
|
| 35 | #include <linux/rwsem.h>
|
| 36 | #include <linux/memory.h>
|
| 37 | #include <linux/ipc_namespace.h>
|
| 38 |
|
| 39 | #include <asm/unistd.h>
|
| 40 |
|
| 41 | #include "util.h"
|
| 42 |
|
| 43 | struct ipc_proc_iface {
|
| 44 | const char *path;
|
| 45 | const char *header;
|
| 46 | int ids;
|
| 47 | int (*show)(struct seq_file *, void *);
|
| 48 | };
|
| 49 |
|
| 50 | #ifdef CONFIG_MEMORY_HOTPLUG
|
| 51 |
|
| 52 | static void ipc_memory_notifier(struct work_struct *work)
|
| 53 | {
|
| 54 | ipcns_notify(IPCNS_MEMCHANGED);
|
| 55 | }
|
| 56 |
|
| 57 | static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier);
|
| 58 |
|
| 59 |
|
| 60 | static int ipc_memory_callback(struct notifier_block *self,
|
| 61 | unsigned long action, void *arg)
|
| 62 | {
|
| 63 | switch (action) {
|
| 64 | case MEM_ONLINE:
|
| 65 | case MEM_OFFLINE:
|
| 66 | |
| 67 | * This is done by invoking the ipcns notifier chain with the
|
| 68 | * IPC_MEMCHANGED event.
|
| 69 | * In order not to keep the lock on the hotplug memory chain
|
| 70 | * for too long, queue a work item that will, when waken up,
|
| 71 | * activate the ipcns notification chain.
|
| 72 | * No need to keep several ipc work items on the queue.
|
| 73 |
|
| 74 | if (!work_pending(&ipc_memory_wq))
|
| 75 | schedule_work(&ipc_memory_wq);
|
| 76 | break;
|
| 77 | case MEM_GOING_ONLINE:
|
| 78 | case MEM_GOING_OFFLINE:
|
| 79 | case MEM_CANCEL_ONLINE:
|
| 80 | case MEM_CANCEL_OFFLINE:
|
| 81 | default:
|
| 82 | break;
|
| 83 | }
|
| 84 |
|
| 85 | return NOTIFY_OK;
|
| 86 | }
|
| 87 |
|
| 88 | #endif
|
| 89 |
|
| 90 | |
| 91 | * ipc_init - initialise IPC subsystem
|
| 92 | *
|
| 93 | * The various system5 IPC resources (semaphores, messages and shared
|
| 94 | * memory) are initialised
|
| 95 | * A callback routine is registered into the memory hotplug notifier
|
| 96 | * chain: since msgmni scales to lowmem this callback routine will be
|
| 97 | * called upon successful memory add / remove to recompute msmgni.
|
| 98 |
|
| 99 |
|
| 100 | static int __init ipc_init(void)
|
| 101 | {
|
| 102 | sem_init();
|
| 103 | msg_init();
|
| 104 | shm_init();
|
| 105 | hotplug_memory_notifier(ipc_memory_callback, IPC_CALLBACK_PRI);
|
| 106 | register_ipcns_notifier(&init_ipc_ns);
|
| 107 | return 0;
|
| 108 | }
|
| 109 | __initcall(ipc_init);
|
| 110 |
|
| 111 | |
| 112 | * ipc_init_ids - initialise IPC identifiers
|
| 113 | * @ids: Identifier set
|
| 114 | *
|
| 115 | * Set up the sequence range to use for the ipc identifier range (limited
|
| 116 | * below IPCMNI) then initialise the ids idr.
|
| 117 |
|
| 118 |
|
| 119 | void ipc_init_ids(struct ipc_ids *ids)
|
| 120 | {
|
| 121 | init_rwsem(&ids->rw_mutex);
|
| 122 |
|
| 123 | ids->in_use = 0;
|
| 124 | ids->seq = 0;
|
| 125 | {
|
| 126 | int seq_limit = INT_MAX/SEQ_MULTIPLIER;
|
| 127 | if (seq_limit > USHRT_MAX)
|
| 128 | ids->seq_max = USHRT_MAX;
|
| 129 | else
|
| 130 | ids->seq_max = seq_limit;
|
| 131 | }
|
| 132 |
|
| 133 | idr_init(&ids->ipcs_idr);
|
| 134 | }
|
| 135 |
|
| 136 | #ifdef CONFIG_PROC_FS
|
| 137 | static const struct file_operations sysvipc_proc_fops;
|
| 138 | |
| 139 | * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface.
|
| 140 | * @path: Path in procfs
|
| 141 | * @header: Banner to be printed at the beginning of the file.
|
| 142 | * @ids: ipc id table to iterate.
|
| 143 | * @show: show routine.
|
| 144 |
|
| 145 | void __init ipc_init_proc_interface(const char *path, const char *header,
|
| 146 | int ids, int (*show)(struct seq_file *, void *))
|
| 147 | {
|
| 148 | struct proc_dir_entry *pde;
|
| 149 | struct ipc_proc_iface *iface;
|
| 150 |
|
| 151 | iface = kmalloc(sizeof(*iface), GFP_KERNEL);
|
| 152 | if (!iface)
|
| 153 | return;
|
| 154 | iface->path = path;
|
| 155 | iface->header = header;
|
| 156 | iface->ids = ids;
|
| 157 | iface->show = show;
|
| 158 |
|
| 159 | pde = proc_create_data(path,
|
| 160 | S_IRUGO,
|
| 161 | NULL,
|
| 162 | &sysvipc_proc_fops,
|
| 163 | iface);
|
| 164 | if (!pde) {
|
| 165 | kfree(iface);
|
| 166 | }
|
| 167 | }
|
| 168 | #endif
|
| 169 |
|
| 170 | |
| 171 | * ipc_findkey - find a key in an ipc identifier set
|
| 172 | * @ids: Identifier set
|
| 173 | * @key: The key to find
|
| 174 | *
|
| 175 | * Requires ipc_ids.rw_mutex locked.
|
| 176 | * Returns the LOCKED pointer to the ipc structure if found or NULL
|
| 177 | * if not.
|
| 178 | * If key is found ipc points to the owning ipc structure
|
| 179 |
|
| 180 |
|
| 181 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
|
| 182 | {
|
| 183 | struct kern_ipc_perm *ipc;
|
| 184 | int next_id;
|
| 185 | int total;
|
| 186 |
|
| 187 | for (total = 0, next_id = 0; total < ids->in_use; next_id++) {
|
| 188 | ipc = idr_find(&ids->ipcs_idr, next_id);
|
| 189 |
|
| 190 | if (ipc == NULL)
|
| 191 | continue;
|
| 192 |
|
| 193 | if (ipc->key != key) {
|
| 194 | total++;
|
| 195 | continue;
|
| 196 | }
|
| 197 |
|
| 198 | ipc_lock_by_ptr(ipc);
|
| 199 | return ipc;
|
| 200 | }
|
| 201 |
|
| 202 | return NULL;
|
| 203 | }
|
| 204 |
|
| 205 | |
| 206 | * ipc_get_maxid - get the last assigned id
|
| 207 | * @ids: IPC identifier set
|
| 208 | *
|
| 209 | * Called with ipc_ids.rw_mutex held.
|
| 210 |
|
| 211 |
|
| 212 | int ipc_get_maxid(struct ipc_ids *ids)
|
| 213 | {
|
| 214 | struct kern_ipc_perm *ipc;
|
| 215 | int max_id = -1;
|
| 216 | int total, id;
|
| 217 |
|
| 218 | if (ids->in_use == 0)
|
| 219 | return -1;
|
| 220 |
|
| 221 | if (ids->in_use == IPCMNI)
|
| 222 | return IPCMNI - 1;
|
| 223 |
|
| 224 |
|
| 225 | total = 0;
|
| 226 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
|
| 227 | ipc = idr_find(&ids->ipcs_idr, id);
|
| 228 | if (ipc != NULL) {
|
| 229 | max_id = id;
|
| 230 | total++;
|
| 231 | }
|
| 232 | }
|
| 233 | return max_id;
|
| 234 | }
|
| 235 |
|
| 236 | |
| 237 | * ipc_addid - add an IPC identifier
|
| 238 | * @ids: IPC identifier set
|
| 239 | * @new: new IPC permission set
|
| 240 | * @size: limit for the number of used ids
|
| 241 | *
|
| 242 | * Add an entry 'new' to the IPC ids idr. The permissions object is
|
| 243 | * initialised and the first free entry is set up and the id assigned
|
| 244 | * is returned. The 'new' entry is returned in a locked state on success.
|
| 245 | * On failure the entry is not locked and a negative err-code is returned.
|
| 246 | *
|
| 247 | * Called with ipc_ids.rw_mutex held as a writer.
|
| 248 |
|
| 249 |
|
| 250 | int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
|
| 251 | {
|
| 252 | uid_t euid;
|
| 253 | gid_t egid;
|
| 254 | int id, err;
|
| 255 |
|
| 256 | if (size > IPCMNI)
|
| 257 | size = IPCMNI;
|
| 258 |
|
| 259 | if (ids->in_use >= size)
|
| 260 | return -ENOSPC;
|
| 261 |
|
| 262 | spin_lock_init(&new->lock);
|
| 263 | new->deleted = 0;
|
| 264 | rcu_read_lock();
|
| 265 | spin_lock(&new->lock);
|
| 266 |
|
| 267 | err = idr_get_new(&ids->ipcs_idr, new, &id);
|
| 268 | if (err) {
|
| 269 | spin_unlock(&new->lock);
|
| 270 | rcu_read_unlock();
|
| 271 | return err;
|
| 272 | }
|
| 273 |
|
| 274 | ids->in_use++;
|
| 275 |
|
| 276 | current_euid_egid(&euid, &egid);
|
| 277 | new->cuid = new->uid = euid;
|
| 278 | new->gid = new->cgid = egid;
|
| 279 |
|
| 280 | new->seq = ids->seq++;
|
| 281 | if(ids->seq > ids->seq_max)
|
| 282 | ids->seq = 0;
|
| 283 |
|
| 284 | new->id = ipc_buildid(id, new->seq);
|
| 285 | return id;
|
| 286 | }
|
| 287 |
|
| 288 | |
| 289 | * ipcget_new - create a new ipc object
|
| 290 | * @ns: namespace
|
| 291 | * @ids: IPC identifer set
|
| 292 | * @ops: the actual creation routine to call
|
| 293 | * @params: its parameters
|
| 294 | *
|
| 295 | * This routine is called by sys_msgget, sys_semget() and sys_shmget()
|
| 296 | * when the key is IPC_PRIVATE.
|
| 297 |
|
| 298 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
|
| 299 | struct ipc_ops *ops, struct ipc_params *params)
|
| 300 | {
|
| 301 | int err;
|
| 302 | retry:
|
| 303 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
|
| 304 |
|
| 305 | if (!err)
|
| 306 | return -ENOMEM;
|
| 307 |
|
| 308 | down_write(&ids->rw_mutex);
|
| 309 | err = ops->getnew(ns, params);
|
| 310 | up_write(&ids->rw_mutex);
|
| 311 |
|
| 312 | if (err == -EAGAIN)
|
| 313 | goto retry;
|
| 314 |
|
| 315 | return err;
|
| 316 | }
|
| 317 |
|
| 318 | |
| 319 | * ipc_check_perms - check security and permissions for an IPC
|
| 320 | * @ns: IPC namespace
|
| 321 | * @ipcp: ipc permission set
|
| 322 | * @ops: the actual security routine to call
|
| 323 | * @params: its parameters
|
| 324 | *
|
| 325 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget()
|
| 326 | * when the key is not IPC_PRIVATE and that key already exists in the
|
| 327 | * ids IDR.
|
| 328 | *
|
| 329 | * On success, the IPC id is returned.
|
| 330 | *
|
| 331 | * It is called with ipc_ids.rw_mutex and ipcp->lock held.
|
| 332 |
|
| 333 | static int ipc_check_perms(struct ipc_namespace *ns,
|
| 334 | struct kern_ipc_perm *ipcp,
|
| 335 | struct ipc_ops *ops,
|
| 336 | struct ipc_params *params)
|
| 337 | {
|
| 338 | int err;
|
| 339 |
|
| 340 | if (ipcperms(ns, ipcp, params->flg))
|
| 341 | err = -EACCES;
|
| 342 | else {
|
| 343 | err = ops->associate(ipcp, params->flg);
|
| 344 | if (!err)
|
| 345 | err = ipcp->id;
|
| 346 | }
|
| 347 |
|
| 348 | return err;
|
| 349 | }
|
| 350 |
|
| 351 | |
| 352 | * ipcget_public - get an ipc object or create a new one
|
| 353 | * @ns: namespace
|
| 354 | * @ids: IPC identifer set
|
| 355 | * @ops: the actual creation routine to call
|
| 356 | * @params: its parameters
|
| 357 | *
|
| 358 | * This routine is called by sys_msgget, sys_semget() and sys_shmget()
|
| 359 | * when the key is not IPC_PRIVATE.
|
| 360 | * It adds a new entry if the key is not found and does some permission
|
| 361 | * / security checkings if the key is found.
|
| 362 | *
|
| 363 | * On success, the ipc id is returned.
|
| 364 |
|
| 365 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
|
| 366 | struct ipc_ops *ops, struct ipc_params *params)
|
| 367 | {
|
| 368 | struct kern_ipc_perm *ipcp;
|
| 369 | int flg = params->flg;
|
| 370 | int err;
|
| 371 | retry:
|
| 372 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
|
| 373 |
|
| 374 | |
| 375 | * Take the lock as a writer since we are potentially going to add
|
| 376 | * a new entry + read locks are not "upgradable"
|
| 377 |
|
| 378 | down_write(&ids->rw_mutex);
|
| 379 | ipcp = ipc_findkey(ids, params->key);
|
| 380 | if (ipcp == NULL) {
|
| 381 |
|
| 382 | if (!(flg & IPC_CREAT))
|
| 383 | err = -ENOENT;
|
| 384 | else if (!err)
|
| 385 | err = -ENOMEM;
|
| 386 | else
|
| 387 | err = ops->getnew(ns, params);
|
| 388 | } else {
|
| 389 |
|
| 390 |
|
| 391 | if (flg & IPC_CREAT && flg & IPC_EXCL)
|
| 392 | err = -EEXIST;
|
| 393 | else {
|
| 394 | err = 0;
|
| 395 | if (ops->more_checks)
|
| 396 | err = ops->more_checks(ipcp, params);
|
| 397 | if (!err)
|
| 398 | |
| 399 | * ipc_check_perms returns the IPC id on
|
| 400 | * success
|
| 401 |
|
| 402 | err = ipc_check_perms(ns, ipcp, ops, params);
|
| 403 | }
|
| 404 | ipc_unlock(ipcp);
|
| 405 | }
|
| 406 | up_write(&ids->rw_mutex);
|
| 407 |
|
| 408 | if (err == -EAGAIN)
|
| 409 | goto retry;
|
| 410 |
|
| 411 | return err;
|
| 412 | }
|
| 413 |
|
| 414 |
|
| 415 | |
| 416 | * ipc_rmid - remove an IPC identifier
|
| 417 | * @ids: IPC identifier set
|
| 418 | * @ipcp: ipc perm structure containing the identifier to remove
|
| 419 | *
|
| 420 | * ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held
|
| 421 | * before this function is called, and remain locked on the exit.
|
| 422 |
|
| 423 |
|
| 424 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
|
| 425 | {
|
| 426 | int lid = ipcid_to_idx(ipcp->id);
|
| 427 |
|
| 428 | idr_remove(&ids->ipcs_idr, lid);
|
| 429 |
|
| 430 | ids->in_use--;
|
| 431 |
|
| 432 | ipcp->deleted = 1;
|
| 433 |
|
| 434 | return;
|
| 435 | }
|
| 436 |
|
| 437 | |
| 438 | * ipc_alloc - allocate ipc space
|
| 439 | * @size: size desired
|
| 440 | *
|
| 441 | * Allocate memory from the appropriate pools and return a pointer to it.
|
| 442 | * NULL is returned if the allocation fails
|
| 443 |
|
| 444 |
|
| 445 | void* ipc_alloc(int size)
|
| 446 | {
|
| 447 | void* out;
|
| 448 | if(size > PAGE_SIZE)
|
| 449 | out = vmalloc(size);
|
| 450 | else
|
| 451 | out = kmalloc(size, GFP_KERNEL);
|
| 452 | return out;
|
| 453 | }
|
| 454 |
|
| 455 | |
| 456 | * ipc_free - free ipc space
|
| 457 | * @ptr: pointer returned by ipc_alloc
|
| 458 | * @size: size of block
|
| 459 | *
|
| 460 | * Free a block created with ipc_alloc(). The caller must know the size
|
| 461 | * used in the allocation call.
|
| 462 |
|
| 463 |
|
| 464 | void ipc_free(void* ptr, int size)
|
| 465 | {
|
| 466 | if(size > PAGE_SIZE)
|
| 467 | vfree(ptr);
|
| 468 | else
|
| 469 | kfree(ptr);
|
| 470 | }
|
| 471 |
|
| 472 | |
| 473 | * rcu allocations:
|
| 474 | * There are three headers that are prepended to the actual allocation:
|
| 475 | * - during use: ipc_rcu_hdr.
|
| 476 | * - during the rcu grace period: ipc_rcu_grace.
|
| 477 | * - [only if vmalloc]: ipc_rcu_sched.
|
| 478 | * Their lifetime doesn't overlap, thus the headers share the same memory.
|
| 479 | * Unlike a normal union, they are right-aligned, thus some container_of
|
| 480 | * forward/backward casting is necessary:
|
| 481 |
|
| 482 | struct ipc_rcu_hdr
|
| 483 | {
|
| 484 | int refcount;
|
| 485 | int is_vmalloc;
|
| 486 | void *data[0];
|
| 487 | };
|
| 488 |
|
| 489 |
|
| 490 | struct ipc_rcu_grace
|
| 491 | {
|
| 492 | struct rcu_head rcu;
|
| 493 |
|
| 494 | void *data[0];
|
| 495 | };
|
| 496 |
|
| 497 | struct ipc_rcu_sched
|
| 498 | {
|
| 499 | struct work_struct work;
|
| 500 |
|
| 501 | void *data[0];
|
| 502 | };
|
| 503 |
|
| 504 | #define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \
|
| 505 | sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr))
|
| 506 | #define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \
|
| 507 | sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC)
|
| 508 |
|
| 509 | static inline int rcu_use_vmalloc(int size)
|
| 510 | {
|
| 511 |
|
| 512 | if (HDRLEN_KMALLOC + size > PAGE_SIZE)
|
| 513 | return 1;
|
| 514 | return 0;
|
| 515 | }
|
| 516 |
|
| 517 | |
| 518 | * ipc_rcu_alloc - allocate ipc and rcu space
|
| 519 | * @size: size desired
|
| 520 | *
|
| 521 | * Allocate memory for the rcu header structure + the object.
|
| 522 | * Returns the pointer to the object.
|
| 523 | * NULL is returned if the allocation fails.
|
| 524 |
|
| 525 |
|
| 526 | void* ipc_rcu_alloc(int size)
|
| 527 | {
|
| 528 | void* out;
|
| 529 | |
| 530 | * We prepend the allocation with the rcu struct, and
|
| 531 | * workqueue if necessary (for vmalloc).
|
| 532 |
|
| 533 | if (rcu_use_vmalloc(size)) {
|
| 534 | out = vmalloc(HDRLEN_VMALLOC + size);
|
| 535 | if (out) {
|
| 536 | out += HDRLEN_VMALLOC;
|
| 537 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1;
|
| 538 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
|
| 539 | }
|
| 540 | } else {
|
| 541 | out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL);
|
| 542 | if (out) {
|
| 543 | out += HDRLEN_KMALLOC;
|
| 544 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0;
|
| 545 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
|
| 546 | }
|
| 547 | }
|
| 548 |
|
| 549 | return out;
|
| 550 | }
|
| 551 |
|
| 552 | void ipc_rcu_getref(void *ptr)
|
| 553 | {
|
| 554 | container_of(ptr, struct ipc_rcu_hdr, data)->refcount++;
|
| 555 | }
|
| 556 |
|
| 557 | static void ipc_do_vfree(struct work_struct *work)
|
| 558 | {
|
| 559 | vfree(container_of(work, struct ipc_rcu_sched, work));
|
| 560 | }
|
| 561 |
|
| 562 | |
| 563 | * ipc_schedule_free - free ipc + rcu space
|
| 564 | * @head: RCU callback structure for queued work
|
| 565 | *
|
| 566 | * Since RCU callback function is called in bh,
|
| 567 | * we need to defer the vfree to schedule_work().
|
| 568 |
|
| 569 | static void ipc_schedule_free(struct rcu_head *head)
|
| 570 | {
|
| 571 | struct ipc_rcu_grace *grace;
|
| 572 | struct ipc_rcu_sched *sched;
|
| 573 |
|
| 574 | grace = container_of(head, struct ipc_rcu_grace, rcu);
|
| 575 | sched = container_of(&(grace->data[0]), struct ipc_rcu_sched,
|
| 576 | data[0]);
|
| 577 |
|
| 578 | INIT_WORK(&sched->work, ipc_do_vfree);
|
| 579 | schedule_work(&sched->work);
|
| 580 | }
|
| 581 |
|
| 582 | void ipc_rcu_putref(void *ptr)
|
| 583 | {
|
| 584 | if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0)
|
| 585 | return;
|
| 586 |
|
| 587 | if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) {
|
| 588 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
|
| 589 | ipc_schedule_free);
|
| 590 | } else {
|
| 591 | kfree_rcu(container_of(ptr, struct ipc_rcu_grace, data), rcu);
|
| 592 | }
|
| 593 | }
|
| 594 |
|
| 595 | |
| 596 | * ipcperms - check IPC permissions
|
| 597 | * @ns: IPC namespace
|
| 598 | * @ipcp: IPC permission set
|
| 599 | * @flag: desired permission set.
|
| 600 | *
|
| 601 | * Check user, group, other permissions for access
|
| 602 | * to ipc resources. return 0 if allowed
|
| 603 | *
|
| 604 | * @flag will most probably be 0 or S_...UGO from <linux/stat.h>
|
| 605 |
|
| 606 |
|
| 607 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag)
|
| 608 | {
|
| 609 | uid_t euid = current_euid();
|
| 610 | int requested_mode, granted_mode;
|
| 611 |
|
| 612 | audit_ipc_obj(ipcp);
|
| 613 | requested_mode = (flag >> 6) | (flag >> 3) | flag;
|
| 614 | granted_mode = ipcp->mode;
|
| 615 | if (euid == ipcp->cuid ||
|
| 616 | euid == ipcp->uid)
|
| 617 | granted_mode >>= 6;
|
| 618 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
|
| 619 | granted_mode >>= 3;
|
| 620 |
|
| 621 | if ((requested_mode & ~granted_mode & 0007) &&
|
| 622 | !ns_capable(ns->user_ns, CAP_IPC_OWNER))
|
| 623 | return -1;
|
| 624 |
|
| 625 | return security_ipc_permission(ipcp, flag);
|
| 626 | }
|
| 627 |
|
| 628 | |
| 629 | * Functions to convert between the kern_ipc_perm structure and the
|
| 630 | * old/new ipc_perm structures
|
| 631 |
|
| 632 |
|
| 633 | |
| 634 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user
|
| 635 | * @in: kernel permissions
|
| 636 | * @out: new style IPC permissions
|
| 637 | *
|
| 638 | * Turn the kernel object @in into a set of permissions descriptions
|
| 639 | * for returning to userspace (@out).
|
| 640 |
|
| 641 |
|
| 642 |
|
| 643 | void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out)
|
| 644 | {
|
| 645 | out->key = in->key;
|
| 646 | out->uid = in->uid;
|
| 647 | out->gid = in->gid;
|
| 648 | out->cuid = in->cuid;
|
| 649 | out->cgid = in->cgid;
|
| 650 | out->mode = in->mode;
|
| 651 | out->seq = in->seq;
|
| 652 | }
|
| 653 |
|
| 654 | |
| 655 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old
|
| 656 | * @in: new style IPC permissions
|
| 657 | * @out: old style IPC permissions
|
| 658 | *
|
| 659 | * Turn the new style permissions object @in into a compatibility
|
| 660 | * object and store it into the @out pointer.
|
| 661 |
|
| 662 |
|
| 663 | void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out)
|
| 664 | {
|
| 665 | out->key = in->key;
|
| 666 | SET_UID(out->uid, in->uid);
|
| 667 | SET_GID(out->gid, in->gid);
|
| 668 | SET_UID(out->cuid, in->cuid);
|
| 669 | SET_GID(out->cgid, in->cgid);
|
| 670 | out->mode = in->mode;
|
| 671 | out->seq = in->seq;
|
| 672 | }
|
| 673 |
|
| 674 | |
| 675 | * ipc_lock - Lock an ipc structure without rw_mutex held
|
| 676 | * @ids: IPC identifier set
|
| 677 | * @id: ipc id to look for
|
| 678 | *
|
| 679 | * Look for an id in the ipc ids idr and lock the associated ipc object.
|
| 680 | *
|
| 681 | * The ipc object is locked on exit.
|
| 682 |
|
| 683 |
|
| 684 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
|
| 685 | {
|
| 686 | struct kern_ipc_perm *out;
|
| 687 | int lid = ipcid_to_idx(id);
|
| 688 |
|
| 689 | rcu_read_lock();
|
| 690 | out = idr_find(&ids->ipcs_idr, lid);
|
| 691 | if (out == NULL) {
|
| 692 | rcu_read_unlock();
|
| 693 | return ERR_PTR(-EINVAL);
|
| 694 | }
|
| 695 |
|
| 696 | spin_lock(&out->lock);
|
| 697 |
|
| 698 | |
| 699 | * was spinning: here verify that the structure is still valid
|
| 700 |
|
| 701 | if (out->deleted) {
|
| 702 | spin_unlock(&out->lock);
|
| 703 | rcu_read_unlock();
|
| 704 | return ERR_PTR(-EINVAL);
|
| 705 | }
|
| 706 |
|
| 707 | return out;
|
| 708 | }
|
| 709 |
|
| 710 | struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id)
|
| 711 | {
|
| 712 | struct kern_ipc_perm *out;
|
| 713 |
|
| 714 | out = ipc_lock(ids, id);
|
| 715 | if (IS_ERR(out))
|
| 716 | return out;
|
| 717 |
|
| 718 | if (ipc_checkid(out, id)) {
|
| 719 | ipc_unlock(out);
|
| 720 | return ERR_PTR(-EIDRM);
|
| 721 | }
|
| 722 |
|
| 723 | return out;
|
| 724 | }
|
| 725 |
|
| 726 | |
| 727 | * ipcget - Common sys_*get() code
|
| 728 | * @ns : namsepace
|
| 729 | * @ids : IPC identifier set
|
| 730 | * @ops : operations to be called on ipc object creation, permission checks
|
| 731 | * and further checks
|
| 732 | * @params : the parameters needed by the previous operations.
|
| 733 | *
|
| 734 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget().
|
| 735 |
|
| 736 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
|
| 737 | struct ipc_ops *ops, struct ipc_params *params)
|
| 738 | {
|
| 739 | if (params->key == IPC_PRIVATE)
|
| 740 | return ipcget_new(ns, ids, ops, params);
|
| 741 | else
|
| 742 | return ipcget_public(ns, ids, ops, params);
|
| 743 | }
|
| 744 |
|
| 745 | |
| 746 | * ipc_update_perm - update the permissions of an IPC.
|
| 747 | * @in: the permission given as input.
|
| 748 | * @out: the permission of the ipc to set.
|
| 749 |
|
| 750 | void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
|
| 751 | {
|
| 752 | out->uid = in->uid;
|
| 753 | out->gid = in->gid;
|
| 754 | out->mode = (out->mode & ~S_IRWXUGO)
|
| 755 | | (in->mode & S_IRWXUGO);
|
| 756 | }
|
| 757 |
|
| 758 | |
| 759 | * ipcctl_pre_down - retrieve an ipc and check permissions for some IPC_XXX cmd
|
| 760 | * @ns: the ipc namespace
|
| 761 | * @ids: the table of ids where to look for the ipc
|
| 762 | * @id: the id of the ipc to retrieve
|
| 763 | * @cmd: the cmd to check
|
| 764 | * @perm: the permission to set
|
| 765 | * @extra_perm: one extra permission parameter used by msq
|
| 766 | *
|
| 767 | * This function does some common audit and permissions check for some IPC_XXX
|
| 768 | * cmd and is called from semctl_down, shmctl_down and msgctl_down.
|
| 769 | * It must be called without any lock held and
|
| 770 | * - retrieves the ipc with the given id in the given table.
|
| 771 | * - performs some audit and permission check, depending on the given cmd
|
| 772 | * - returns the ipc with both ipc and rw_mutex locks held in case of success
|
| 773 | * or an err-code without any lock held otherwise.
|
| 774 |
|
| 775 | struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
|
| 776 | struct ipc_ids *ids, int id, int cmd,
|
| 777 | struct ipc64_perm *perm, int extra_perm)
|
| 778 | {
|
| 779 | struct kern_ipc_perm *ipcp;
|
| 780 | uid_t euid;
|
| 781 | int err;
|
| 782 |
|
| 783 | down_write(&ids->rw_mutex);
|
| 784 | ipcp = ipc_lock_check(ids, id);
|
| 785 | if (IS_ERR(ipcp)) {
|
| 786 | err = PTR_ERR(ipcp);
|
| 787 | goto out_up;
|
| 788 | }
|
| 789 |
|
| 790 | audit_ipc_obj(ipcp);
|
| 791 | if (cmd == IPC_SET)
|
| 792 | audit_ipc_set_perm(extra_perm, perm->uid,
|
| 793 | perm->gid, perm->mode);
|
| 794 |
|
| 795 | euid = current_euid();
|
| 796 | if (euid == ipcp->cuid || euid == ipcp->uid ||
|
| 797 | ns_capable(ns->user_ns, CAP_SYS_ADMIN))
|
| 798 | return ipcp;
|
| 799 |
|
| 800 | err = -EPERM;
|
| 801 | ipc_unlock(ipcp);
|
| 802 | out_up:
|
| 803 | up_write(&ids->rw_mutex);
|
| 804 | return ERR_PTR(err);
|
| 805 | }
|
| 806 |
|
| 807 | #ifdef __ARCH_WANT_IPC_PARSE_VERSION
|
| 808 |
|
| 809 |
|
| 810 | |
| 811 | * ipc_parse_version - IPC call version
|
| 812 | * @cmd: pointer to command
|
| 813 | *
|
| 814 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
|
| 815 | * The @cmd value is turned from an encoding command and version into
|
| 816 | * just the command code.
|
| 817 |
|
| 818 |
|
| 819 | int ipc_parse_version (int *cmd)
|
| 820 | {
|
| 821 | if (*cmd & IPC_64) {
|
| 822 | *cmd ^= IPC_64;
|
| 823 | return IPC_64;
|
| 824 | } else {
|
| 825 | return IPC_OLD;
|
| 826 | }
|
| 827 | }
|
| 828 |
|
| 829 | #endif
|
| 830 |
|
| 831 | #ifdef CONFIG_PROC_FS
|
| 832 | struct ipc_proc_iter {
|
| 833 | struct ipc_namespace *ns;
|
| 834 | struct ipc_proc_iface *iface;
|
| 835 | };
|
| 836 |
|
| 837 | |
| 838 | * This routine locks the ipc structure found at least at position pos.
|
| 839 |
|
| 840 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
|
| 841 | loff_t *new_pos)
|
| 842 | {
|
| 843 | struct kern_ipc_perm *ipc;
|
| 844 | int total, id;
|
| 845 |
|
| 846 | total = 0;
|
| 847 | for (id = 0; id < pos && total < ids->in_use; id++) {
|
| 848 | ipc = idr_find(&ids->ipcs_idr, id);
|
| 849 | if (ipc != NULL)
|
| 850 | total++;
|
| 851 | }
|
| 852 |
|
| 853 | if (total >= ids->in_use)
|
| 854 | return NULL;
|
| 855 |
|
| 856 | for ( ; pos < IPCMNI; pos++) {
|
| 857 | ipc = idr_find(&ids->ipcs_idr, pos);
|
| 858 | if (ipc != NULL) {
|
| 859 | *new_pos = pos + 1;
|
| 860 | ipc_lock_by_ptr(ipc);
|
| 861 | return ipc;
|
| 862 | }
|
| 863 | }
|
| 864 |
|
| 865 |
|
| 866 | return NULL;
|
| 867 | }
|
| 868 |
|
| 869 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
|
| 870 | {
|
| 871 | struct ipc_proc_iter *iter = s->private;
|
| 872 | struct ipc_proc_iface *iface = iter->iface;
|
| 873 | struct kern_ipc_perm *ipc = it;
|
| 874 |
|
| 875 |
|
| 876 | if (ipc && ipc != SEQ_START_TOKEN)
|
| 877 | ipc_unlock(ipc);
|
| 878 |
|
| 879 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos);
|
| 880 | }
|
| 881 |
|
| 882 | |
| 883 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1.
|
| 884 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
|
| 885 |
|
| 886 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
|
| 887 | {
|
| 888 | struct ipc_proc_iter *iter = s->private;
|
| 889 | struct ipc_proc_iface *iface = iter->iface;
|
| 890 | struct ipc_ids *ids;
|
| 891 |
|
| 892 | ids = &iter->ns->ids[iface->ids];
|
| 893 |
|
| 894 | |
| 895 | * Take the lock - this will be released by the corresponding
|
| 896 | * call to stop().
|
| 897 |
|
| 898 | down_read(&ids->rw_mutex);
|
| 899 |
|
| 900 |
|
| 901 | if (*pos < 0)
|
| 902 | return NULL;
|
| 903 |
|
| 904 |
|
| 905 | if (*pos == 0)
|
| 906 | return SEQ_START_TOKEN;
|
| 907 |
|
| 908 |
|
| 909 | return sysvipc_find_ipc(ids, *pos - 1, pos);
|
| 910 | }
|
| 911 |
|
| 912 | static void sysvipc_proc_stop(struct seq_file *s, void *it)
|
| 913 | {
|
| 914 | struct kern_ipc_perm *ipc = it;
|
| 915 | struct ipc_proc_iter *iter = s->private;
|
| 916 | struct ipc_proc_iface *iface = iter->iface;
|
| 917 | struct ipc_ids *ids;
|
| 918 |
|
| 919 |
|
| 920 | if (ipc && ipc != SEQ_START_TOKEN)
|
| 921 | ipc_unlock(ipc);
|
| 922 |
|
| 923 | ids = &iter->ns->ids[iface->ids];
|
| 924 |
|
| 925 | up_read(&ids->rw_mutex);
|
| 926 | }
|
| 927 |
|
| 928 | static int sysvipc_proc_show(struct seq_file *s, void *it)
|
| 929 | {
|
| 930 | struct ipc_proc_iter *iter = s->private;
|
| 931 | struct ipc_proc_iface *iface = iter->iface;
|
| 932 |
|
| 933 | if (it == SEQ_START_TOKEN)
|
| 934 | return seq_puts(s, iface->header);
|
| 935 |
|
| 936 | return iface->show(s, it);
|
| 937 | }
|
| 938 |
|
| 939 | static const struct seq_operations sysvipc_proc_seqops = {
|
| 940 | .start = sysvipc_proc_start,
|
| 941 | .stop = sysvipc_proc_stop,
|
| 942 | .next = sysvipc_proc_next,
|
| 943 | .show = sysvipc_proc_show,
|
| 944 | };
|
| 945 |
|
| 946 | static int sysvipc_proc_open(struct inode *inode, struct file *file)
|
| 947 | {
|
| 948 | int ret;
|
| 949 | struct seq_file *seq;
|
| 950 | struct ipc_proc_iter *iter;
|
| 951 |
|
| 952 | ret = -ENOMEM;
|
| 953 | iter = kmalloc(sizeof(*iter), GFP_KERNEL);
|
| 954 | if (!iter)
|
| 955 | goto out;
|
| 956 |
|
| 957 | ret = seq_open(file, &sysvipc_proc_seqops);
|
| 958 | if (ret)
|
| 959 | goto out_kfree;
|
| 960 |
|
| 961 | seq = file->private_data;
|
| 962 | seq->private = iter;
|
| 963 |
|
| 964 | iter->iface = PDE(inode)->data;
|
| 965 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
|
| 966 | out:
|
| 967 | return ret;
|
| 968 | out_kfree:
|
| 969 | kfree(iter);
|
| 970 | goto out;
|
| 971 | }
|
| 972 |
|
| 973 | static int sysvipc_proc_release(struct inode *inode, struct file *file)
|
| 974 | {
|
| 975 | struct seq_file *seq = file->private_data;
|
| 976 | struct ipc_proc_iter *iter = seq->private;
|
| 977 | put_ipc_ns(iter->ns);
|
| 978 | return seq_release_private(inode, file);
|
| 979 | }
|
| 980 |
|
| 981 | static const struct file_operations sysvipc_proc_fops = {
|
| 982 | .open = sysvipc_proc_open,
|
| 983 | .read = seq_read,
|
| 984 | .llseek = seq_lseek,
|
| 985 | .release = sysvipc_proc_release,
|
| 986 | };
|
| 987 | #endif
|