shm.c 33.5 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
/*
 * linux/ipc/shm.c
 * Copyright (C) 1992, 1993 Krishna Balasubramanian
 *	 Many improvements/fixes by Bruno Haible.
 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
 *
 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
 *
Steve Grubb's avatar
Steve Grubb committed
16 17
 * support for audit of ipc object properties and permission changes
 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
Kirill Korotaev's avatar
Kirill Korotaev committed
18 19 20 21
 *
 * namespaces support
 * OpenVZ, SWsoft Inc.
 * Pavel Emelianov <xemul@openvz.org>
22 23 24
 *
 * Better ipc lock (kern_ipc_perm.lock) handling
 * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
Linus Torvalds's avatar
Linus Torvalds committed
25 26 27 28 29 30 31 32 33 34 35 36 37
 */

#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/shm.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/mman.h>
#include <linux/shmem_fs.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
38
#include <linux/capability.h>
39
#include <linux/ptrace.h>
40
#include <linux/seq_file.h>
Nadia Derbey's avatar
Nadia Derbey committed
41
#include <linux/rwsem.h>
Kirill Korotaev's avatar
Kirill Korotaev committed
42
#include <linux/nsproxy.h>
43
#include <linux/mount.h>
44
#include <linux/ipc_namespace.h>
45

Paul McQuade's avatar
Paul McQuade committed
46
#include <linux/uaccess.h>
Linus Torvalds's avatar
Linus Torvalds committed
47 48 49

#include "util.h"

50 51 52 53 54 55 56 57 58
struct shm_file_data {
	int id;
	struct ipc_namespace *ns;
	struct file *file;
	const struct vm_operations_struct *vm_ops;
};

#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))

59
static const struct file_operations shm_file_operations;
60
static const struct vm_operations_struct shm_vm_ops;
Linus Torvalds's avatar
Linus Torvalds committed
61

62
#define shm_ids(ns)	((ns)->ids[IPC_SHM_IDS])
Linus Torvalds's avatar
Linus Torvalds committed
63

Kirill Korotaev's avatar
Kirill Korotaev committed
64 65
#define shm_unlock(shp)			\
	ipc_unlock(&(shp)->shm_perm)
Linus Torvalds's avatar
Linus Torvalds committed
66

Nadia Derbey's avatar
Nadia Derbey committed
67
static int newseg(struct ipc_namespace *, struct ipc_params *);
68 69
static void shm_open(struct vm_area_struct *vma);
static void shm_close(struct vm_area_struct *vma);
Manfred Spraul's avatar
Manfred Spraul committed
70
static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
Linus Torvalds's avatar
Linus Torvalds committed
71
#ifdef CONFIG_PROC_FS
72
static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
Linus Torvalds's avatar
Linus Torvalds committed
73 74
#endif

75
void shm_init_ns(struct ipc_namespace *ns)
Kirill Korotaev's avatar
Kirill Korotaev committed
76 77 78 79
{
	ns->shm_ctlmax = SHMMAX;
	ns->shm_ctlall = SHMALL;
	ns->shm_ctlmni = SHMMNI;
80
	ns->shm_rmid_forced = 0;
Kirill Korotaev's avatar
Kirill Korotaev committed
81
	ns->shm_tot = 0;
WANG Cong's avatar
WANG Cong committed
82
	ipc_init_ids(&shm_ids(ns));
Kirill Korotaev's avatar
Kirill Korotaev committed
83 84
}

Nadia Derbey's avatar
Nadia Derbey committed
85
/*
Davidlohr Bueso's avatar
Davidlohr Bueso committed
86 87
 * Called with shm_ids.rwsem (writer) and the shp structure locked.
 * Only shm_ids.rwsem remains locked on exit.
Nadia Derbey's avatar
Nadia Derbey committed
88
 */
89
static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Kirill Korotaev's avatar
Kirill Korotaev committed
90
{
91
	struct shmid_kernel *shp;
92

93 94
	shp = container_of(ipcp, struct shmid_kernel, shm_perm);

Manfred Spraul's avatar
Manfred Spraul committed
95
	if (shp->shm_nattch) {
Kirill Korotaev's avatar
Kirill Korotaev committed
96 97 98 99 100 101 102 103
		shp->shm_perm.mode |= SHM_DEST;
		/* Do not find it any more */
		shp->shm_perm.key = IPC_PRIVATE;
		shm_unlock(shp);
	} else
		shm_destroy(ns, shp);
}

104
#ifdef CONFIG_IPC_NS
Kirill Korotaev's avatar
Kirill Korotaev committed
105 106
void shm_exit_ns(struct ipc_namespace *ns)
{
107
	free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
108
	idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
Kirill Korotaev's avatar
Kirill Korotaev committed
109
}
110
#endif
Linus Torvalds's avatar
Linus Torvalds committed
111

112
static int __init ipc_ns_init(void)
Linus Torvalds's avatar
Linus Torvalds committed
113
{
114
	shm_init_ns(&init_ipc_ns);
115 116 117 118 119
	return 0;
}

pure_initcall(ipc_ns_init);

Manfred Spraul's avatar
Manfred Spraul committed
120
void __init shm_init(void)
121
{
122
	ipc_init_proc_interface("sysvipc/shm",
123 124 125 126 127
#if BITS_PER_LONG <= 32
				"       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
#else
				"       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n",
#endif
Kirill Korotaev's avatar
Kirill Korotaev committed
128
				IPC_SHM_IDS, sysvipc_shm_proc_show);
Linus Torvalds's avatar
Linus Torvalds committed
129 130
}

131 132
static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
{
133
	struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150

	if (IS_ERR(ipcp))
		return ERR_CAST(ipcp);

	return container_of(ipcp, struct shmid_kernel, shm_perm);
}

static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
{
	struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);

	if (IS_ERR(ipcp))
		return ERR_CAST(ipcp);

	return container_of(ipcp, struct shmid_kernel, shm_perm);
}

Nadia Derbey's avatar
Nadia Derbey committed
151
/*
Davidlohr Bueso's avatar
Davidlohr Bueso committed
152
 * shm_lock_(check_) routines are called in the paths where the rwsem
Nadia Derbey's avatar
Nadia Derbey committed
153
 * is not necessarily held.
Nadia Derbey's avatar
Nadia Derbey committed
154
 */
155
static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
Linus Torvalds's avatar
Linus Torvalds committed
156
{
Nadia Derbey's avatar
Nadia Derbey committed
157 158
	struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);

159
	/*
160 161 162
	 * Callers of shm_lock() must validate the status of the returned ipc
	 * object pointer (as returned by ipc_lock()), and error out as
	 * appropriate.
163
	 */
164 165
	if (IS_ERR(ipcp))
		return (void *)ipcp;
Nadia Derbey's avatar
Nadia Derbey committed
166
	return container_of(ipcp, struct shmid_kernel, shm_perm);
167 168
}

169 170 171
static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
{
	rcu_read_lock();
172
	ipc_lock_object(&ipcp->shm_perm);
173 174
}

Davidlohr Bueso's avatar
Davidlohr Bueso committed
175 176 177 178 179 180 181 182 183
static void shm_rcu_free(struct rcu_head *head)
{
	struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
	struct shmid_kernel *shp = ipc_rcu_to_struct(p);

	security_shm_free(shp);
	ipc_rcu_free(head);
}

Nadia Derbey's avatar
Nadia Derbey committed
184
static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
Linus Torvalds's avatar
Linus Torvalds committed
185
{
186
	list_del(&s->shm_clist);
Nadia Derbey's avatar
Nadia Derbey committed
187
	ipc_rmid(&shm_ids(ns), &s->shm_perm);
Linus Torvalds's avatar
Linus Torvalds committed
188 189 190
}


191
static int __shm_open(struct vm_area_struct *vma)
Kirill Korotaev's avatar
Kirill Korotaev committed
192
{
193 194
	struct file *file = vma->vm_file;
	struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds's avatar
Linus Torvalds committed
195 196
	struct shmid_kernel *shp;

197
	shp = shm_lock(sfd->ns, sfd->id);
198 199 200 201

	if (IS_ERR(shp))
		return PTR_ERR(shp);

Linus Torvalds's avatar
Linus Torvalds committed
202
	shp->shm_atim = get_seconds();
203
	shp->shm_lprid = task_tgid_vnr(current);
Linus Torvalds's avatar
Linus Torvalds committed
204 205
	shp->shm_nattch++;
	shm_unlock(shp);
206 207 208 209 210 211 212 213 214 215 216 217
	return 0;
}

/* This is called by fork, once for every shm attach. */
static void shm_open(struct vm_area_struct *vma)
{
	int err = __shm_open(vma);
	/*
	 * We raced in the idr lookup or with shm_destroy().
	 * Either way, the ID is busted.
	 */
	WARN_ON_ONCE(err);
Linus Torvalds's avatar
Linus Torvalds committed
218 219 220 221 222
}

/*
 * shm_destroy - free the struct shmid_kernel
 *
Nadia Derbey's avatar
Nadia Derbey committed
223
 * @ns: namespace
Linus Torvalds's avatar
Linus Torvalds committed
224 225
 * @shp: struct to free
 *
Davidlohr Bueso's avatar
Davidlohr Bueso committed
226
 * It has to be called with shp and shm_ids.rwsem (writer) locked,
Linus Torvalds's avatar
Linus Torvalds committed
227 228
 * but returns with shp unlocked and freed.
 */
Kirill Korotaev's avatar
Kirill Korotaev committed
229
static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds's avatar
Linus Torvalds committed
230
{
231 232 233 234
	struct file *shm_file;

	shm_file = shp->shm_file;
	shp->shm_file = NULL;
Kirill Korotaev's avatar
Kirill Korotaev committed
235
	ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
Nadia Derbey's avatar
Nadia Derbey committed
236
	shm_rmid(ns, shp);
Linus Torvalds's avatar
Linus Torvalds committed
237
	shm_unlock(shp);
238 239
	if (!is_file_hugepages(shm_file))
		shmem_lock(shm_file, 0, shp->mlock_user);
240
	else if (shp->mlock_user)
241 242
		user_shm_unlock(i_size_read(file_inode(shm_file)),
				shp->mlock_user);
243
	fput(shm_file);
Davidlohr Bueso's avatar
Davidlohr Bueso committed
244
	ipc_rcu_putref(shp, shm_rcu_free);
Linus Torvalds's avatar
Linus Torvalds committed
245 246
}

247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263
/*
 * shm_may_destroy - identifies whether shm segment should be destroyed now
 *
 * Returns true if and only if there are no active users of the segment and
 * one of the following is true:
 *
 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
 *
 * 2) sysctl kernel.shm_rmid_forced is set to 1.
 */
static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
{
	return (shp->shm_nattch == 0) &&
	       (ns->shm_rmid_forced ||
		(shp->shm_perm.mode & SHM_DEST));
}

Linus Torvalds's avatar
Linus Torvalds committed
264
/*
265
 * remove the attach descriptor vma.
Linus Torvalds's avatar
Linus Torvalds committed
266 267 268 269
 * free memory for segment if it is marked destroyed.
 * The descriptor has already been removed from the current->mm->mmap list
 * and will later be kfree()d.
 */
270
static void shm_close(struct vm_area_struct *vma)
Linus Torvalds's avatar
Linus Torvalds committed
271
{
Manfred Spraul's avatar
Manfred Spraul committed
272
	struct file *file = vma->vm_file;
273
	struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds's avatar
Linus Torvalds committed
274
	struct shmid_kernel *shp;
275
	struct ipc_namespace *ns = sfd->ns;
Kirill Korotaev's avatar
Kirill Korotaev committed
276

Davidlohr Bueso's avatar
Davidlohr Bueso committed
277
	down_write(&shm_ids(ns).rwsem);
Linus Torvalds's avatar
Linus Torvalds committed
278
	/* remove from the list of attaches of the shm segment */
Nadia Derbey's avatar
Nadia Derbey committed
279
	shp = shm_lock(ns, sfd->id);
280 281 282 283 284 285 286 287

	/*
	 * We raced in the idr lookup or with shm_destroy().
	 * Either way, the ID is busted.
	 */
	if (WARN_ON_ONCE(IS_ERR(shp)))
		goto done; /* no-op */

288
	shp->shm_lprid = task_tgid_vnr(current);
Linus Torvalds's avatar
Linus Torvalds committed
289 290
	shp->shm_dtim = get_seconds();
	shp->shm_nattch--;
291 292 293 294
	if (shm_may_destroy(ns, shp))
		shm_destroy(ns, shp);
	else
		shm_unlock(shp);
295
done:
Davidlohr Bueso's avatar
Davidlohr Bueso committed
296
	up_write(&shm_ids(ns).rwsem);
297 298
}

Davidlohr Bueso's avatar
Davidlohr Bueso committed
299
/* Called with ns->shm_ids(ns).rwsem locked */
300 301 302
static int shm_try_destroy_orphaned(int id, void *p, void *data)
{
	struct ipc_namespace *ns = data;
303 304
	struct kern_ipc_perm *ipcp = p;
	struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
305 306 307 308

	/*
	 * We want to destroy segments without users and with already
	 * exit'ed originating process.
309
	 *
Davidlohr Bueso's avatar
Davidlohr Bueso committed
310
	 * As shp->* are changed under rwsem, it's safe to skip shp locking.
311
	 */
312
	if (shp->shm_creator != NULL)
313 314
		return 0;

315 316
	if (shm_may_destroy(ns, shp)) {
		shm_lock_by_ptr(shp);
Kirill Korotaev's avatar
Kirill Korotaev committed
317
		shm_destroy(ns, shp);
318
	}
319 320 321 322 323
	return 0;
}

void shm_destroy_orphaned(struct ipc_namespace *ns)
{
Davidlohr Bueso's avatar
Davidlohr Bueso committed
324
	down_write(&shm_ids(ns).rwsem);
Vasiliy Kulikov's avatar
Vasiliy Kulikov committed
325
	if (shm_ids(ns).in_use)
326
		idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
Davidlohr Bueso's avatar
Davidlohr Bueso committed
327
	up_write(&shm_ids(ns).rwsem);
328 329
}

330
/* Locking assumes this will only be called with task == current */
331 332
void exit_shm(struct task_struct *task)
{
333
	struct ipc_namespace *ns = task->nsproxy->ipc_ns;
334
	struct shmid_kernel *shp, *n;
335

336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353
	if (list_empty(&task->sysvshm.shm_clist))
		return;

	/*
	 * If kernel.shm_rmid_forced is not set then only keep track of
	 * which shmids are orphaned, so that a later set of the sysctl
	 * can clean them up.
	 */
	if (!ns->shm_rmid_forced) {
		down_read(&shm_ids(ns).rwsem);
		list_for_each_entry(shp, &task->sysvshm.shm_clist, shm_clist)
			shp->shm_creator = NULL;
		/*
		 * Only under read lock but we are only called on current
		 * so no entry on the list will be shared.
		 */
		list_del(&task->sysvshm.shm_clist);
		up_read(&shm_ids(ns).rwsem);
Vasiliy Kulikov's avatar
Vasiliy Kulikov committed
354
		return;
355
	}
Vasiliy Kulikov's avatar
Vasiliy Kulikov committed
356

357 358 359 360 361
	/*
	 * Destroy all already created segments, that were not yet mapped,
	 * and mark any mapped as orphan to cover the sysctl toggling.
	 * Destroy is skipped if shm_may_destroy() returns false.
	 */
Davidlohr Bueso's avatar
Davidlohr Bueso committed
362
	down_write(&shm_ids(ns).rwsem);
363 364 365 366 367 368 369 370 371 372
	list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) {
		shp->shm_creator = NULL;

		if (shm_may_destroy(ns, shp)) {
			shm_lock_by_ptr(shp);
			shm_destroy(ns, shp);
		}
	}

	/* Remove the list head from any segments still attached. */
373
	list_del(&task->sysvshm.shm_clist);
Davidlohr Bueso's avatar
Davidlohr Bueso committed
374
	up_write(&shm_ids(ns).rwsem);
Linus Torvalds's avatar
Linus Torvalds committed
375 376
}

377
static int shm_fault(struct vm_fault *vmf)
378
{
379
	struct file *file = vmf->vma->vm_file;
380 381
	struct shm_file_data *sfd = shm_file_data(file);

382
	return sfd->vm_ops->fault(vmf);
383 384 385
}

#ifdef CONFIG_NUMA
386
static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
387 388 389 390
{
	struct file *file = vma->vm_file;
	struct shm_file_data *sfd = shm_file_data(file);
	int err = 0;
391

392 393 394 395 396
	if (sfd->vm_ops->set_policy)
		err = sfd->vm_ops->set_policy(vma, new);
	return err;
}

397 398
static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
					unsigned long addr)
399 400 401 402 403 404 405
{
	struct file *file = vma->vm_file;
	struct shm_file_data *sfd = shm_file_data(file);
	struct mempolicy *pol = NULL;

	if (sfd->vm_ops->get_policy)
		pol = sfd->vm_ops->get_policy(vma, addr);
406
	else if (vma->vm_policy)
407
		pol = vma->vm_policy;
408

409 410 411 412
	return pol;
}
#endif

Manfred Spraul's avatar
Manfred Spraul committed
413
static int shm_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds's avatar
Linus Torvalds committed
414
{
415
	struct shm_file_data *sfd = shm_file_data(file);
416 417
	int ret;

418 419 420 421
	/*
	 * In case of remap_file_pages() emulation, the file can represent
	 * removed IPC ID: propogate shm_lock() error to caller.
	 */
422
	ret = __shm_open(vma);
423 424 425
	if (ret)
		return ret;

426
	ret = call_mmap(sfd->file, vma);
427 428
	if (ret) {
		shm_close(vma);
429
		return ret;
430
	}
431
	sfd->vm_ops = vma->vm_ops;
David Howells's avatar
David Howells committed
432
#ifdef CONFIG_MMU
433
	WARN_ON(!sfd->vm_ops->fault);
David Howells's avatar
David Howells committed
434
#endif
435
	vma->vm_ops = &shm_vm_ops;
436
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
437 438
}

Kirill Korotaev's avatar
Kirill Korotaev committed
439 440
static int shm_release(struct inode *ino, struct file *file)
{
441
	struct shm_file_data *sfd = shm_file_data(file);
Kirill Korotaev's avatar
Kirill Korotaev committed
442

443 444 445
	put_ipc_ns(sfd->ns);
	shm_file_data(file) = NULL;
	kfree(sfd);
Kirill Korotaev's avatar
Kirill Korotaev committed
446 447 448
	return 0;
}

449
static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
450 451 452
{
	struct shm_file_data *sfd = shm_file_data(file);

453 454
	if (!sfd->file->f_op->fsync)
		return -EINVAL;
455
	return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
456 457
}

458 459 460 461 462 463 464 465 466 467
static long shm_fallocate(struct file *file, int mode, loff_t offset,
			  loff_t len)
{
	struct shm_file_data *sfd = shm_file_data(file);

	if (!sfd->file->f_op->fallocate)
		return -EOPNOTSUPP;
	return sfd->file->f_op->fallocate(file, mode, offset, len);
}

468 469 470 471 472
static unsigned long shm_get_unmapped_area(struct file *file,
	unsigned long addr, unsigned long len, unsigned long pgoff,
	unsigned long flags)
{
	struct shm_file_data *sfd = shm_file_data(file);
473

474 475
	return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
						pgoff, flags);
476 477
}

478
static const struct file_operations shm_file_operations = {
Kirill Korotaev's avatar
Kirill Korotaev committed
479
	.mmap		= shm_mmap,
480
	.fsync		= shm_fsync,
Kirill Korotaev's avatar
Kirill Korotaev committed
481
	.release	= shm_release,
David Howells's avatar
David Howells committed
482
	.get_unmapped_area	= shm_get_unmapped_area,
483
	.llseek		= noop_llseek,
484
	.fallocate	= shm_fallocate,
485 486
};

487 488 489 490
/*
 * shm_file_operations_huge is now identical to shm_file_operations,
 * but we keep it distinct for the sake of is_file_shm_hugepages().
 */
491 492 493 494
static const struct file_operations shm_file_operations_huge = {
	.mmap		= shm_mmap,
	.fsync		= shm_fsync,
	.release	= shm_release,
495
	.get_unmapped_area	= shm_get_unmapped_area,
496
	.llseek		= noop_llseek,
497
	.fallocate	= shm_fallocate,
Linus Torvalds's avatar
Linus Torvalds committed
498 499
};

500
bool is_file_shm_hugepages(struct file *file)
501 502 503 504
{
	return file->f_op == &shm_file_operations_huge;
}

505
static const struct vm_operations_struct shm_vm_ops = {
Linus Torvalds's avatar
Linus Torvalds committed
506 507
	.open	= shm_open,	/* callback for a new vm-area open */
	.close	= shm_close,	/* callback for when the vm-area is released */
508
	.fault	= shm_fault,
509 510 511
#if defined(CONFIG_NUMA)
	.set_policy = shm_set_policy,
	.get_policy = shm_get_policy,
Linus Torvalds's avatar
Linus Torvalds committed
512 513 514
#endif
};

Nadia Derbey's avatar
Nadia Derbey committed
515 516 517 518 519
/**
 * newseg - Create a new shared memory segment
 * @ns: namespace
 * @params: ptr to the structure that contains key, size and shmflg
 *
Davidlohr Bueso's avatar
Davidlohr Bueso committed
520
 * Called with shm_ids.rwsem held as a writer.
Nadia Derbey's avatar
Nadia Derbey committed
521
 */
Nadia Derbey's avatar
Nadia Derbey committed
522
static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds's avatar
Linus Torvalds committed
523
{
Nadia Derbey's avatar
Nadia Derbey committed
524 525 526
	key_t key = params->key;
	int shmflg = params->flg;
	size_t size = params->u.size;
Linus Torvalds's avatar
Linus Torvalds committed
527 528
	int error;
	struct shmid_kernel *shp;
529
	size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
Manfred Spraul's avatar
Manfred Spraul committed
530
	struct file *file;
Linus Torvalds's avatar
Linus Torvalds committed
531 532
	char name[13];
	int id;
533
	vm_flags_t acctflag = 0;
Linus Torvalds's avatar
Linus Torvalds committed
534

Kirill Korotaev's avatar
Kirill Korotaev committed
535
	if (size < SHMMIN || size > ns->shm_ctlmax)
Linus Torvalds's avatar
Linus Torvalds committed
536 537
		return -EINVAL;

538 539 540
	if (numpages << PAGE_SHIFT < size)
		return -ENOSPC;

541 542
	if (ns->shm_tot + numpages < ns->shm_tot ||
			ns->shm_tot + numpages > ns->shm_ctlall)
Linus Torvalds's avatar
Linus Torvalds committed
543 544 545 546 547 548 549
		return -ENOSPC;

	shp = ipc_rcu_alloc(sizeof(*shp));
	if (!shp)
		return -ENOMEM;

	shp->shm_perm.key = key;
Andrew Morton's avatar
Andrew Morton committed
550
	shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Linus Torvalds's avatar
Linus Torvalds committed
551 552 553 554 555
	shp->mlock_user = NULL;

	shp->shm_perm.security = NULL;
	error = security_shm_alloc(shp);
	if (error) {
Davidlohr Bueso's avatar
Davidlohr Bueso committed
556
		ipc_rcu_putref(shp, ipc_rcu_free);
Linus Torvalds's avatar
Linus Torvalds committed
557 558 559
		return error;
	}

Manfred Spraul's avatar
Manfred Spraul committed
560
	sprintf(name, "SYSV%08x", key);
Linus Torvalds's avatar
Linus Torvalds committed
561
	if (shmflg & SHM_HUGETLB) {
562
		struct hstate *hs;
563 564
		size_t hugesize;

565
		hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
566 567 568 569 570
		if (!hs) {
			error = -EINVAL;
			goto no_file;
		}
		hugesize = ALIGN(size, huge_page_size(hs));
571

572 573 574
		/* hugetlb_file_setup applies strict accounting */
		if (shmflg & SHM_NORESERVE)
			acctflag = VM_NORESERVE;
575
		file = hugetlb_file_setup(name, hugesize, acctflag,
576 577
				  &shp->mlock_user, HUGETLB_SHMFS_INODE,
				(shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
Linus Torvalds's avatar
Linus Torvalds committed
578
	} else {
579 580
		/*
		 * Do not allow no accounting for OVERCOMMIT_NEVER, even
Manfred Spraul's avatar
Manfred Spraul committed
581
		 * if it's asked for.
582 583 584
		 */
		if  ((shmflg & SHM_NORESERVE) &&
				sysctl_overcommit_memory != OVERCOMMIT_NEVER)
585
			acctflag = VM_NORESERVE;
586
		file = shmem_kernel_file_setup(name, size, acctflag);
Linus Torvalds's avatar
Linus Torvalds committed
587 588 589 590 591
	}
	error = PTR_ERR(file);
	if (IS_ERR(file))
		goto no_file;

592
	shp->shm_cprid = task_tgid_vnr(current);
Linus Torvalds's avatar
Linus Torvalds committed
593 594 595 596 597 598
	shp->shm_lprid = 0;
	shp->shm_atim = shp->shm_dtim = 0;
	shp->shm_ctim = get_seconds();
	shp->shm_segsz = size;
	shp->shm_nattch = 0;
	shp->shm_file = file;
599
	shp->shm_creator = current;
600 601 602 603 604 605 606

	id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
	if (id < 0) {
		error = id;
		goto no_id;
	}

607
	list_add(&shp->shm_clist, &current->sysvshm.shm_clist);
608

609 610 611 612
	/*
	 * shmid gets reported as "inode#" in /proc/pid/maps.
	 * proc-ps tools use this. Changing this will break them.
	 */
Al Viro's avatar
Al Viro committed
613
	file_inode(file)->i_ino = shp->shm_perm.id;
614

Kirill Korotaev's avatar
Kirill Korotaev committed
615
	ns->shm_tot += numpages;
Nadia Derbey's avatar
Nadia Derbey committed
616
	error = shp->shm_perm.id;
617

618
	ipc_unlock_object(&shp->shm_perm);
619
	rcu_read_unlock();
Nadia Derbey's avatar
Nadia Derbey committed
620
	return error;
Linus Torvalds's avatar
Linus Torvalds committed
621 622

no_id:
623
	if (is_file_hugepages(file) && shp->mlock_user)
624
		user_shm_unlock(size, shp->mlock_user);
Linus Torvalds's avatar
Linus Torvalds committed
625 626
	fput(file);
no_file:
Davidlohr Bueso's avatar
Davidlohr Bueso committed
627
	ipc_rcu_putref(shp, shm_rcu_free);
Linus Torvalds's avatar
Linus Torvalds committed
628 629 630
	return error;
}

Nadia Derbey's avatar
Nadia Derbey committed
631
/*
Davidlohr Bueso's avatar
Davidlohr Bueso committed
632
 * Called with shm_ids.rwsem and ipcp locked.
Nadia Derbey's avatar
Nadia Derbey committed
633
 */
Nadia Derbey's avatar
Nadia Derbey committed
634
static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
Nadia Derbey's avatar
Nadia Derbey committed
635
{
Nadia Derbey's avatar
Nadia Derbey committed
636 637 638 639
	struct shmid_kernel *shp;

	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
	return security_shm_associate(shp, shmflg);
Nadia Derbey's avatar
Nadia Derbey committed
640 641
}

Nadia Derbey's avatar
Nadia Derbey committed
642
/*
Davidlohr Bueso's avatar
Davidlohr Bueso committed
643
 * Called with shm_ids.rwsem and ipcp locked.
Nadia Derbey's avatar
Nadia Derbey committed
644
 */
Nadia Derbey's avatar
Nadia Derbey committed
645 646
static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
				struct ipc_params *params)
Nadia Derbey's avatar
Nadia Derbey committed
647
{
Nadia Derbey's avatar
Nadia Derbey committed
648 649 650 651
	struct shmid_kernel *shp;

	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
	if (shp->shm_segsz < params->u.size)
Nadia Derbey's avatar
Nadia Derbey committed
652 653 654 655 656
		return -EINVAL;

	return 0;
}

657
SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
Linus Torvalds's avatar
Linus Torvalds committed
658
{
Kirill Korotaev's avatar
Kirill Korotaev committed
659
	struct ipc_namespace *ns;
Mathias Krause's avatar
Mathias Krause committed
660 661 662 663 664
	static const struct ipc_ops shm_ops = {
		.getnew = newseg,
		.associate = shm_security,
		.more_checks = shm_more_checks,
	};
Nadia Derbey's avatar
Nadia Derbey committed
665
	struct ipc_params shm_params;
Kirill Korotaev's avatar
Kirill Korotaev committed
666 667

	ns = current->nsproxy->ipc_ns;
Linus Torvalds's avatar
Linus Torvalds committed
668

Nadia Derbey's avatar
Nadia Derbey committed
669 670 671
	shm_params.key = key;
	shm_params.flg = shmflg;
	shm_params.u.size = size;
Linus Torvalds's avatar
Linus Torvalds committed
672

Nadia Derbey's avatar
Nadia Derbey committed
673
	return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
Linus Torvalds's avatar
Linus Torvalds committed
674 675 676 677
}

static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
{
Manfred Spraul's avatar
Manfred Spraul committed
678
	switch (version) {
Linus Torvalds's avatar
Linus Torvalds committed
679 680 681 682 683 684
	case IPC_64:
		return copy_to_user(buf, in, sizeof(*in));
	case IPC_OLD:
	    {
		struct shmid_ds out;

685
		memset(&out, 0, sizeof(out));
Linus Torvalds's avatar
Linus Torvalds committed
686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701
		ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
		out.shm_segsz	= in->shm_segsz;
		out.shm_atime	= in->shm_atime;
		out.shm_dtime	= in->shm_dtime;
		out.shm_ctime	= in->shm_ctime;
		out.shm_cpid	= in->shm_cpid;
		out.shm_lpid	= in->shm_lpid;
		out.shm_nattch	= in->shm_nattch;

		return copy_to_user(buf, &out, sizeof(out));
	    }
	default:
		return -EINVAL;
	}
}

702 703
static inline unsigned long
copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
Linus Torvalds's avatar
Linus Torvalds committed
704
{
Manfred Spraul's avatar
Manfred Spraul committed
705
	switch (version) {
Linus Torvalds's avatar
Linus Torvalds committed
706
	case IPC_64:
707
		if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds's avatar
Linus Torvalds committed
708 709 710 711 712 713 714 715 716
			return -EFAULT;
		return 0;
	case IPC_OLD:
	    {
		struct shmid_ds tbuf_old;

		if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
			return -EFAULT;

717 718 719
		out->shm_perm.uid	= tbuf_old.shm_perm.uid;
		out->shm_perm.gid	= tbuf_old.shm_perm.gid;
		out->shm_perm.mode	= tbuf_old.shm_perm.mode;
Linus Torvalds's avatar
Linus Torvalds committed
720 721 722 723 724 725 726 727 728 729

		return 0;
	    }
	default:
		return -EINVAL;
	}
}

static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
{
Manfred Spraul's avatar
Manfred Spraul committed
730
	switch (version) {
Linus Torvalds's avatar
Linus Torvalds committed
731 732 733 734 735 736
	case IPC_64:
		return copy_to_user(buf, in, sizeof(*in));
	case IPC_OLD:
	    {
		struct shminfo out;

Manfred Spraul's avatar
Manfred Spraul committed
737
		if (in->shmmax > INT_MAX)
Linus Torvalds's avatar
Linus Torvalds committed
738 739 740 741 742 743 744
			out.shmmax = INT_MAX;
		else
			out.shmmax = (int)in->shmmax;

		out.shmmin	= in->shmmin;
		out.shmmni	= in->shmmni;
		out.shmseg	= in->shmseg;
Paul McQuade's avatar
Paul McQuade committed
745
		out.shmall	= in->shmall;
Linus Torvalds's avatar
Linus Torvalds committed
746 747 748 749 750 751 752 753

		return copy_to_user(buf, &out, sizeof(out));
	    }
	default:
		return -EINVAL;
	}
}

754 755
/*
 * Calculate and add used RSS and swap pages of a shm.
Davidlohr Bueso's avatar
Davidlohr Bueso committed
756
 * Called with shm_ids.rwsem held as a reader
757 758 759 760 761 762
 */
static void shm_add_rss_swap(struct shmid_kernel *shp,
	unsigned long *rss_add, unsigned long *swp_add)
{
	struct inode *inode;

Al Viro's avatar
Al Viro committed
763
	inode = file_inode(shp->shm_file);
764 765 766 767 768 769 770 771

	if (is_file_hugepages(shp->shm_file)) {
		struct address_space *mapping = inode->i_mapping;
		struct hstate *h = hstate_file(shp->shm_file);
		*rss_add += pages_per_huge_page(h) * mapping->nrpages;
	} else {
#ifdef CONFIG_SHMEM
		struct shmem_inode_info *info = SHMEM_I(inode);
772

773
		spin_lock_irq(&info->lock);
774 775
		*rss_add += inode->i_mapping->nrpages;
		*swp_add += info->swapped;
776
		spin_unlock_irq(&info->lock);
777 778 779 780 781 782
#else
		*rss_add += inode->i_mapping->nrpages;
#endif
	}
}

Nadia Derbey's avatar
Nadia Derbey committed
783
/*
Davidlohr Bueso's avatar
Davidlohr Bueso committed
784
 * Called with shm_ids.rwsem held as a reader
Nadia Derbey's avatar
Nadia Derbey committed
785
 */
Kirill Korotaev's avatar
Kirill Korotaev committed
786 787
static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
		unsigned long *swp)
Linus Torvalds's avatar
Linus Torvalds committed
788
{
Nadia Derbey's avatar
Nadia Derbey committed
789 790
	int next_id;
	int total, in_use;
Linus Torvalds's avatar
Linus Torvalds committed
791 792 793 794

	*rss = 0;
	*swp = 0;

Nadia Derbey's avatar
Nadia Derbey committed
795 796 797
	in_use = shm_ids(ns).in_use;

	for (total = 0, next_id = 0; total < in_use; next_id++) {
798
		struct kern_ipc_perm *ipc;
Linus Torvalds's avatar
Linus Torvalds committed
799 800
		struct shmid_kernel *shp;

801 802
		ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
		if (ipc == NULL)
Linus Torvalds's avatar
Linus Torvalds committed
803
			continue;
804
		shp = container_of(ipc, struct shmid_kernel, shm_perm);
Linus Torvalds's avatar
Linus Torvalds committed
805

806
		shm_add_rss_swap(shp, rss, swp);
Nadia Derbey's avatar
Nadia Derbey committed
807 808

		total++;
Linus Torvalds's avatar
Linus Torvalds committed
809 810 811
	}
}

812
/*
Davidlohr Bueso's avatar
Davidlohr Bueso committed
813
 * This function handles some shmctl commands which require the rwsem
814
 * to be held in write mode.
Davidlohr Bueso's avatar
Davidlohr Bueso committed
815
 * NOTE: no locks must be held, the rwsem is taken inside this function.
816 817 818
 */
static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
		       struct shmid_ds __user *buf, int version)
Linus Torvalds's avatar
Linus Torvalds committed
819
{
820
	struct kern_ipc_perm *ipcp;
821
	struct shmid64_ds shmid64;
822 823 824 825
	struct shmid_kernel *shp;
	int err;

	if (cmd == IPC_SET) {
826
		if (copy_shmid_from_user(&shmid64, buf, version))
827 828 829
			return -EFAULT;
	}

Davidlohr Bueso's avatar
Davidlohr Bueso committed
830
	down_write(&shm_ids(ns).rwsem);
831 832
	rcu_read_lock();

833 834
	ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
				      &shmid64.shm_perm, 0);
835 836 837 838
	if (IS_ERR(ipcp)) {
		err = PTR_ERR(ipcp);
		goto out_unlock1;
	}
839

840
	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
841 842 843

	err = security_shm_shmctl(shp, cmd);
	if (err)
844
		goto out_unlock1;
845

846 847
	switch (cmd) {
	case IPC_RMID:
848
		ipc_lock_object(&shp->shm_perm);
849
		/* do_shm_rmid unlocks the ipc object and rcu */
850 851 852
		do_shm_rmid(ns, ipcp);
		goto out_up;
	case IPC_SET:
853
		ipc_lock_object(&shp->shm_perm);
854 855
		err = ipc_update_perm(&shmid64.shm_perm, ipcp);
		if (err)
856
			goto out_unlock0;
857 858 859 860
		shp->shm_ctim = get_seconds();
		break;
	default:
		err = -EINVAL;
861
		goto out_unlock1;
862
	}
863 864 865 866 867

out_unlock0:
	ipc_unlock_object(&shp->shm_perm);
out_unlock1:
	rcu_read_unlock();
868
out_up:
Davidlohr Bueso's avatar
Davidlohr Bueso committed
869
	up_write(&shm_ids(ns).rwsem);
870 871 872
	return err;
}

873 874
static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
			 int cmd, int version, void __user *buf)
875
{
876
	int err;
Linus Torvalds's avatar
Linus Torvalds committed
877 878
	struct shmid_kernel *shp;

879 880 881 882 883
	/* preliminary security checks for *_INFO */
	if (cmd == IPC_INFO || cmd == SHM_INFO) {
		err = security_shm_shmctl(NULL, cmd);
		if (err)
			return err;
Linus Torvalds's avatar
Linus Torvalds committed
884 885
	}

886
	switch (cmd) {
Linus Torvalds's avatar
Linus Torvalds committed
887 888 889 890
	case IPC_INFO:
	{
		struct shminfo64 shminfo;

WANG Cong's avatar
WANG Cong committed
891
		memset(&shminfo, 0, sizeof(shminfo));
Kirill Korotaev's avatar
Kirill Korotaev committed
892 893 894
		shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
		shminfo.shmmax = ns->shm_ctlmax;
		shminfo.shmall = ns->shm_ctlall;
Linus Torvalds's avatar
Linus Torvalds committed
895 896

		shminfo.shmmin = SHMMIN;
Manfred Spraul's avatar
Manfred Spraul committed
897
		if (copy_shminfo_to_user(buf, &shminfo, version))
Linus Torvalds's avatar
Linus Torvalds committed
898
			return -EFAULT;
Nadia Derbey's avatar
Nadia Derbey committed
899

Davidlohr Bueso's avatar
Davidlohr Bueso committed
900
		down_read(&shm_ids(ns).rwsem);
Nadia Derbey's avatar
Nadia Derbey committed
901
		err = ipc_get_maxid(&shm_ids(ns));
Davidlohr Bueso's avatar
Davidlohr Bueso committed
902
		up_read(&shm_ids(ns).rwsem);
Nadia Derbey's avatar
Nadia Derbey committed
903

Manfred Spraul's avatar
Manfred Spraul committed
904
		if (err < 0)
Linus Torvalds's avatar
Linus Torvalds committed
905 906 907 908 909 910 911
			err = 0;
		goto out;
	}
	case SHM_INFO:
	{
		struct shm_info shm_info;

WANG Cong's avatar
WANG Cong committed
912
		memset(&shm_info, 0, sizeof(shm_info));
Davidlohr Bueso's avatar
Davidlohr Bueso committed
913
		down_read(&shm_ids(ns).rwsem);
Kirill Korotaev's avatar
Kirill Korotaev committed
914
		shm_info.used_ids = shm_ids(ns).in_use;
Manfred Spraul's avatar
Manfred Spraul committed
915
		shm_get_stat(ns, &shm_info.shm_rss, &shm_info.shm_swp);
Kirill Korotaev's avatar
Kirill Korotaev committed
916
		shm_info.shm_tot = ns->shm_tot;
Linus Torvalds's avatar
Linus Torvalds committed
917 918
		shm_info.swap_attempts = 0;
		shm_info.swap_successes = 0;
Nadia Derbey's avatar
Nadia Derbey committed
919
		err = ipc_get_maxid(&shm_ids(ns));
Davidlohr Bueso's avatar
Davidlohr Bueso committed
920
		up_read(&shm_ids(ns).rwsem);
WANG Cong's avatar
WANG Cong committed
921
		if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
Linus Torvalds's avatar
Linus Torvalds committed
922 923 924 925 926 927 928 929 930 931 932 933
			err = -EFAULT;
			goto out;
		}

		err = err < 0 ? 0 : err;
		goto out;
	}
	case SHM_STAT:
	case IPC_STAT:
	{
		struct shmid64_ds tbuf;
		int result;
934

935
		rcu_read_lock();
936
		if (cmd == SHM_STAT) {
937
			shp = shm_obtain_object(ns, shmid);
938 939
			if (IS_ERR(shp)) {
				err = PTR_ERR(shp);
940
				goto out_unlock;
941
			}
Nadia Derbey's avatar
Nadia Derbey committed
942
			result = shp->shm_perm.id;
Linus Torvalds's avatar
Linus Torvalds committed
943
		} else {
944
			shp = shm_obtain_object_check(ns, shmid);
945 946
			if (IS_ERR(shp)) {
				err = PTR_ERR(shp);
947
				goto out_unlock;
948
			}
Linus Torvalds's avatar
Linus Torvalds committed
949 950
			result = 0;
		}
951

WANG Cong's avatar
WANG Cong committed
952
		err = -EACCES;
953
		if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
Linus Torvalds's avatar
Linus Torvalds committed
954
			goto out_unlock;
955

Linus Torvalds's avatar
Linus Torvalds committed
956 957 958
		err = security_shm_shmctl(shp, cmd);
		if (err)
			goto out_unlock;
959

960
		memset(&tbuf, 0, sizeof(tbuf));
Linus Torvalds's avatar
Linus Torvalds committed
961 962 963 964 965 966 967
		kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
		tbuf.shm_segsz	= shp->shm_segsz;
		tbuf.shm_atime	= shp->shm_atim;
		tbuf.shm_dtime	= shp->shm_dtim;
		tbuf.shm_ctime	= shp->shm_ctim;
		tbuf.shm_cpid	= shp->shm_cprid;
		tbuf.shm_lpid	= shp->shm_lprid;
968
		tbuf.shm_nattch	= shp->shm_nattch;
969 970 971
		rcu_read_unlock();

		if (copy_shmid_to_user(buf, &tbuf, version))
Linus Torvalds's avatar
Linus Torvalds committed
972 973 974 975 976
			err = -EFAULT;
		else
			err = result;
		goto out;
	}
977 978 979 980 981
	default:
		return -EINVAL;
	}

out_unlock:
982
	rcu_read_unlock();
983 984 985 986 987 988 989 990 991 992
out:
	return err;
}

SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
{
	struct shmid_kernel *shp;
	int err, version;
	struct ipc_namespace *ns;

993 994
	if (cmd < 0 || shmid < 0)
		return -EINVAL;
995 996 997 998 999 1000 1001 1002 1003 1004

	version = ipc_parse_version(&cmd);
	ns = current->nsproxy->ipc_ns;

	switch (cmd) {
	case IPC_INFO:
	case SHM_INFO:
	case SHM_STAT:
	case IPC_STAT:
		return shmctl_nolock(ns, shmid, cmd, version, buf);
1005 1006 1007
	case IPC_RMID:
	case IPC_SET:
		return shmctl_down(ns, shmid, cmd, buf, version);
Linus Torvalds's avatar
Linus Torvalds committed
1008 1009 1010
	case SHM_LOCK:
	case SHM_UNLOCK:
	{
1011
		struct file *shm_file;
1012

1013 1014
		rcu_read_lock();
		shp = shm_obtain_object_check(ns, shmid);
1015 1016
		if (IS_ERR(shp)) {
			err = PTR_ERR(shp);
1017
			goto out_unlock1;
Linus Torvalds's avatar
Linus Torvalds committed
1018 1019
		}

Al Viro's avatar
Al Viro committed
1020
		audit_ipc_obj(&(shp->shm_perm));
1021 1022 1023
		err = security_shm_shmctl(shp, cmd);
		if (err)
			goto out_unlock1;
Steve Grubb's avatar
Steve Grubb committed
1024

1025
		ipc_lock_object(&shp->shm_perm);
1026 1027 1028 1029 1030 1031 1032

		/* check if shm_destroy() is tearing down shp */
		if (!ipc_valid_object(&shp->shm_perm)) {
			err = -EIDRM;
			goto out_unlock0;
		}

1033
		if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
1034
			kuid_t euid = current_euid();
1035

1036
			if (!uid_eq(euid, shp->shm_perm.uid) &&
1037 1038
			    !uid_eq(euid, shp->shm_perm.cuid)) {
				err = -EPERM;
1039
				goto out_unlock0;
1040 1041 1042
			}
			if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
				err = -EPERM;
1043
				goto out_unlock0;
1044
			}
Linus Torvalds's avatar
Linus Torvalds committed
1045 1046
		}

1047 1048
		shm_file = shp->shm_file;
		if (is_file_hugepages(shm_file))
1049
			goto out_unlock0;
1050 1051

		if (cmd == SHM_LOCK) {
1052
			struct user_struct *user = current_user();
1053

1054 1055 1056 1057
			err = shmem_lock(shm_file, 1, user);
			if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
				shp->shm_perm.mode |= SHM_LOCKED;
				shp->mlock_user = user;
Linus Torvalds's avatar
Linus Torvalds committed
1058
			}
1059
			goto out_unlock0;
Linus Torvalds's avatar
Linus Torvalds committed
1060
		}
1061 1062 1063

		/* SHM_UNLOCK */
		if (!(shp->shm_perm.mode & SHM_LOCKED))
1064
			goto out_unlock0;
1065 1066 1067 1068
		shmem_lock(shm_file, 0, shp->mlock_user);
		shp->shm_perm.mode &= ~SHM_LOCKED;
		shp->mlock_user = NULL;
		get_file(shm_file);
1069 1070
		ipc_unlock_object(&shp->shm_perm);
		rcu_read_unlock();
1071
		shmem_unlock_mapping(shm_file->f_mapping);
1072

1073
		fput(shm_file);
Pierre Peiffer's avatar