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1/*
2 * linux/ipc/shm.c
3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
4 * Many improvements/fixes by Bruno Haible.
5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
7 *
8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
15 *
16 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
18 *
19 * namespaces support
20 * OpenVZ, SWsoft Inc.
21 * Pavel Emelianov <xemul@openvz.org>
22 *
23 * Better ipc lock (kern_ipc_perm.lock) handling
24 * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
25 */
26
27#include <linux/slab.h>
28#include <linux/mm.h>
29#include <linux/hugetlb.h>
30#include <linux/shm.h>
31#include <linux/init.h>
32#include <linux/file.h>
33#include <linux/mman.h>
34#include <linux/shmem_fs.h>
35#include <linux/security.h>
36#include <linux/syscalls.h>
37#include <linux/audit.h>
38#include <linux/capability.h>
39#include <linux/ptrace.h>
40#include <linux/seq_file.h>
41#include <linux/rwsem.h>
42#include <linux/nsproxy.h>
43#include <linux/mount.h>
44#include <linux/ipc_namespace.h>
45
46#include <asm/uaccess.h>
47
48#include "util.h"
49
50struct shm_file_data {
51 int id;
52 struct ipc_namespace *ns;
53 struct file *file;
54 const struct vm_operations_struct *vm_ops;
55};
56
57#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
58
59static const struct file_operations shm_file_operations;
60static const struct vm_operations_struct shm_vm_ops;
61
62#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
63
64#define shm_unlock(shp) \
65 ipc_unlock(&(shp)->shm_perm)
66
67static int newseg(struct ipc_namespace *, struct ipc_params *);
68static void shm_open(struct vm_area_struct *vma);
69static void shm_close(struct vm_area_struct *vma);
70static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
71#ifdef CONFIG_PROC_FS
72static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
73#endif
74
75void shm_init_ns(struct ipc_namespace *ns)
76{
77 ns->shm_ctlmax = SHMMAX;
78 ns->shm_ctlall = SHMALL;
79 ns->shm_ctlmni = SHMMNI;
80 ns->shm_rmid_forced = 0;
81 ns->shm_tot = 0;
82 ipc_init_ids(&shm_ids(ns));
83}
84
85/*
86 * Called with shm_ids.rwsem (writer) and the shp structure locked.
87 * Only shm_ids.rwsem remains locked on exit.
88 */
89static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
90{
91 struct shmid_kernel *shp;
92 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
93
94 if (shp->shm_nattch) {
95 shp->shm_perm.mode |= SHM_DEST;
96 /* Do not find it any more */
97 shp->shm_perm.key = IPC_PRIVATE;
98 shm_unlock(shp);
99 } else
100 shm_destroy(ns, shp);
101}
102
103#ifdef CONFIG_IPC_NS
104void shm_exit_ns(struct ipc_namespace *ns)
105{
106 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
107 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
108}
109#endif
110
111static int __init ipc_ns_init(void)
112{
113 shm_init_ns(&init_ipc_ns);
114 return 0;
115}
116
117pure_initcall(ipc_ns_init);
118
119void __init shm_init(void)
120{
121 ipc_init_proc_interface("sysvipc/shm",
122#if BITS_PER_LONG <= 32
123 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
124#else
125 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
126#endif
127 IPC_SHM_IDS, sysvipc_shm_proc_show);
128}
129
130static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
131{
132 struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id);
133
134 if (IS_ERR(ipcp))
135 return ERR_CAST(ipcp);
136
137 return container_of(ipcp, struct shmid_kernel, shm_perm);
138}
139
140static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
141{
142 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
143
144 if (IS_ERR(ipcp))
145 return ERR_CAST(ipcp);
146
147 return container_of(ipcp, struct shmid_kernel, shm_perm);
148}
149
150/*
151 * shm_lock_(check_) routines are called in the paths where the rwsem
152 * is not necessarily held.
153 */
154static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
155{
156 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
157
158 if (IS_ERR(ipcp))
159 return (struct shmid_kernel *)ipcp;
160
161 return container_of(ipcp, struct shmid_kernel, shm_perm);
162}
163
164static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
165{
166 rcu_read_lock();
167 ipc_lock_object(&ipcp->shm_perm);
168}
169
170static void shm_rcu_free(struct rcu_head *head)
171{
172 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
173 struct shmid_kernel *shp = ipc_rcu_to_struct(p);
174
175 security_shm_free(shp);
176 ipc_rcu_free(head);
177}
178
179static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
180{
181 ipc_rmid(&shm_ids(ns), &s->shm_perm);
182}
183
184
185/* This is called by fork, once for every shm attach. */
186static void shm_open(struct vm_area_struct *vma)
187{
188 struct file *file = vma->vm_file;
189 struct shm_file_data *sfd = shm_file_data(file);
190 struct shmid_kernel *shp;
191
192 shp = shm_lock(sfd->ns, sfd->id);
193 BUG_ON(IS_ERR(shp));
194 shp->shm_atim = get_seconds();
195 shp->shm_lprid = task_tgid_vnr(current);
196 shp->shm_nattch++;
197 shm_unlock(shp);
198}
199
200/*
201 * shm_destroy - free the struct shmid_kernel
202 *
203 * @ns: namespace
204 * @shp: struct to free
205 *
206 * It has to be called with shp and shm_ids.rwsem (writer) locked,
207 * but returns with shp unlocked and freed.
208 */
209static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
210{
211 struct file *shm_file;
212
213 shm_file = shp->shm_file;
214 shp->shm_file = NULL;
215 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
216 shm_rmid(ns, shp);
217 shm_unlock(shp);
218 if (!is_file_hugepages(shm_file))
219 shmem_lock(shm_file, 0, shp->mlock_user);
220 else if (shp->mlock_user)
221 user_shm_unlock(file_inode(shm_file)->i_size, shp->mlock_user);
222 fput(shm_file);
223 ipc_rcu_putref(shp, shm_rcu_free);
224}
225
226/*
227 * shm_may_destroy - identifies whether shm segment should be destroyed now
228 *
229 * Returns true if and only if there are no active users of the segment and
230 * one of the following is true:
231 *
232 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
233 *
234 * 2) sysctl kernel.shm_rmid_forced is set to 1.
235 */
236static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
237{
238 return (shp->shm_nattch == 0) &&
239 (ns->shm_rmid_forced ||
240 (shp->shm_perm.mode & SHM_DEST));
241}
242
243/*
244 * remove the attach descriptor vma.
245 * free memory for segment if it is marked destroyed.
246 * The descriptor has already been removed from the current->mm->mmap list
247 * and will later be kfree()d.
248 */
249static void shm_close(struct vm_area_struct *vma)
250{
251 struct file *file = vma->vm_file;
252 struct shm_file_data *sfd = shm_file_data(file);
253 struct shmid_kernel *shp;
254 struct ipc_namespace *ns = sfd->ns;
255
256 down_write(&shm_ids(ns).rwsem);
257 /* remove from the list of attaches of the shm segment */
258 shp = shm_lock(ns, sfd->id);
259 BUG_ON(IS_ERR(shp));
260 shp->shm_lprid = task_tgid_vnr(current);
261 shp->shm_dtim = get_seconds();
262 shp->shm_nattch--;
263 if (shm_may_destroy(ns, shp))
264 shm_destroy(ns, shp);
265 else
266 shm_unlock(shp);
267 up_write(&shm_ids(ns).rwsem);
268}
269
270/* Called with ns->shm_ids(ns).rwsem locked */
271static int shm_try_destroy_current(int id, void *p, void *data)
272{
273 struct ipc_namespace *ns = data;
274 struct kern_ipc_perm *ipcp = p;
275 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
276
277 if (shp->shm_creator != current)
278 return 0;
279
280 /*
281 * Mark it as orphaned to destroy the segment when
282 * kernel.shm_rmid_forced is changed.
283 * It is noop if the following shm_may_destroy() returns true.
284 */
285 shp->shm_creator = NULL;
286
287 /*
288 * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID
289 * is not set, it shouldn't be deleted here.
290 */
291 if (!ns->shm_rmid_forced)
292 return 0;
293
294 if (shm_may_destroy(ns, shp)) {
295 shm_lock_by_ptr(shp);
296 shm_destroy(ns, shp);
297 }
298 return 0;
299}
300
301/* Called with ns->shm_ids(ns).rwsem locked */
302static int shm_try_destroy_orphaned(int id, void *p, void *data)
303{
304 struct ipc_namespace *ns = data;
305 struct kern_ipc_perm *ipcp = p;
306 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
307
308 /*
309 * We want to destroy segments without users and with already
310 * exit'ed originating process.
311 *
312 * As shp->* are changed under rwsem, it's safe to skip shp locking.
313 */
314 if (shp->shm_creator != NULL)
315 return 0;
316
317 if (shm_may_destroy(ns, shp)) {
318 shm_lock_by_ptr(shp);
319 shm_destroy(ns, shp);
320 }
321 return 0;
322}
323
324void shm_destroy_orphaned(struct ipc_namespace *ns)
325{
326 down_write(&shm_ids(ns).rwsem);
327 if (shm_ids(ns).in_use)
328 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
329 up_write(&shm_ids(ns).rwsem);
330}
331
332
333void exit_shm(struct task_struct *task)
334{
335 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
336
337 if (shm_ids(ns).in_use == 0)
338 return;
339
340 /* Destroy all already created segments, but not mapped yet */
341 down_write(&shm_ids(ns).rwsem);
342 if (shm_ids(ns).in_use)
343 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
344 up_write(&shm_ids(ns).rwsem);
345}
346
347static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
348{
349 struct file *file = vma->vm_file;
350 struct shm_file_data *sfd = shm_file_data(file);
351
352 return sfd->vm_ops->fault(vma, vmf);
353}
354
355#ifdef CONFIG_NUMA
356static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
357{
358 struct file *file = vma->vm_file;
359 struct shm_file_data *sfd = shm_file_data(file);
360 int err = 0;
361 if (sfd->vm_ops->set_policy)
362 err = sfd->vm_ops->set_policy(vma, new);
363 return err;
364}
365
366static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
367 unsigned long addr)
368{
369 struct file *file = vma->vm_file;
370 struct shm_file_data *sfd = shm_file_data(file);
371 struct mempolicy *pol = NULL;
372
373 if (sfd->vm_ops->get_policy)
374 pol = sfd->vm_ops->get_policy(vma, addr);
375 else if (vma->vm_policy)
376 pol = vma->vm_policy;
377
378 return pol;
379}
380#endif
381
382static int shm_mmap(struct file *file, struct vm_area_struct *vma)
383{
384 struct shm_file_data *sfd = shm_file_data(file);
385 int ret;
386
387 ret = sfd->file->f_op->mmap(sfd->file, vma);
388 if (ret != 0)
389 return ret;
390 sfd->vm_ops = vma->vm_ops;
391#ifdef CONFIG_MMU
392 BUG_ON(!sfd->vm_ops->fault);
393#endif
394 vma->vm_ops = &shm_vm_ops;
395 shm_open(vma);
396
397 return ret;
398}
399
400static int shm_release(struct inode *ino, struct file *file)
401{
402 struct shm_file_data *sfd = shm_file_data(file);
403
404 put_ipc_ns(sfd->ns);
405 shm_file_data(file) = NULL;
406 kfree(sfd);
407 return 0;
408}
409
410static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
411{
412 struct shm_file_data *sfd = shm_file_data(file);
413
414 if (!sfd->file->f_op->fsync)
415 return -EINVAL;
416 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
417}
418
419static long shm_fallocate(struct file *file, int mode, loff_t offset,
420 loff_t len)
421{
422 struct shm_file_data *sfd = shm_file_data(file);
423
424 if (!sfd->file->f_op->fallocate)
425 return -EOPNOTSUPP;
426 return sfd->file->f_op->fallocate(file, mode, offset, len);
427}
428
429static unsigned long shm_get_unmapped_area(struct file *file,
430 unsigned long addr, unsigned long len, unsigned long pgoff,
431 unsigned long flags)
432{
433 struct shm_file_data *sfd = shm_file_data(file);
434 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
435 pgoff, flags);
436}
437
438static const struct file_operations shm_file_operations = {
439 .mmap = shm_mmap,
440 .fsync = shm_fsync,
441 .release = shm_release,
442#ifndef CONFIG_MMU
443 .get_unmapped_area = shm_get_unmapped_area,
444#endif
445 .llseek = noop_llseek,
446 .fallocate = shm_fallocate,
447};
448
449static const struct file_operations shm_file_operations_huge = {
450 .mmap = shm_mmap,
451 .fsync = shm_fsync,
452 .release = shm_release,
453 .get_unmapped_area = shm_get_unmapped_area,
454 .llseek = noop_llseek,
455 .fallocate = shm_fallocate,
456};
457
458int is_file_shm_hugepages(struct file *file)
459{
460 return file->f_op == &shm_file_operations_huge;
461}
462
463static const struct vm_operations_struct shm_vm_ops = {
464 .open = shm_open, /* callback for a new vm-area open */
465 .close = shm_close, /* callback for when the vm-area is released */
466 .fault = shm_fault,
467#if defined(CONFIG_NUMA)
468 .set_policy = shm_set_policy,
469 .get_policy = shm_get_policy,
470#endif
471};
472
473/**
474 * newseg - Create a new shared memory segment
475 * @ns: namespace
476 * @params: ptr to the structure that contains key, size and shmflg
477 *
478 * Called with shm_ids.rwsem held as a writer.
479 */
480static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
481{
482 key_t key = params->key;
483 int shmflg = params->flg;
484 size_t size = params->u.size;
485 int error;
486 struct shmid_kernel *shp;
487 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
488 struct file *file;
489 char name[13];
490 int id;
491 vm_flags_t acctflag = 0;
492
493 if (size < SHMMIN || size > ns->shm_ctlmax)
494 return -EINVAL;
495
496 if (ns->shm_tot + numpages > ns->shm_ctlall)
497 return -ENOSPC;
498
499 shp = ipc_rcu_alloc(sizeof(*shp));
500 if (!shp)
501 return -ENOMEM;
502
503 shp->shm_perm.key = key;
504 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
505 shp->mlock_user = NULL;
506
507 shp->shm_perm.security = NULL;
508 error = security_shm_alloc(shp);
509 if (error) {
510 ipc_rcu_putref(shp, ipc_rcu_free);
511 return error;
512 }
513
514 sprintf(name, "SYSV%08x", key);
515 if (shmflg & SHM_HUGETLB) {
516 struct hstate *hs;
517 size_t hugesize;
518
519 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
520 if (!hs) {
521 error = -EINVAL;
522 goto no_file;
523 }
524 hugesize = ALIGN(size, huge_page_size(hs));
525
526 /* hugetlb_file_setup applies strict accounting */
527 if (shmflg & SHM_NORESERVE)
528 acctflag = VM_NORESERVE;
529 file = hugetlb_file_setup(name, hugesize, acctflag,
530 &shp->mlock_user, HUGETLB_SHMFS_INODE,
531 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
532 } else {
533 /*
534 * Do not allow no accounting for OVERCOMMIT_NEVER, even
535 * if it's asked for.
536 */
537 if ((shmflg & SHM_NORESERVE) &&
538 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
539 acctflag = VM_NORESERVE;
540 file = shmem_file_setup(name, size, acctflag);
541 }
542 error = PTR_ERR(file);
543 if (IS_ERR(file))
544 goto no_file;
545
546 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
547 if (id < 0) {
548 error = id;
549 goto no_id;
550 }
551
552 shp->shm_cprid = task_tgid_vnr(current);
553 shp->shm_lprid = 0;
554 shp->shm_atim = shp->shm_dtim = 0;
555 shp->shm_ctim = get_seconds();
556 shp->shm_segsz = size;
557 shp->shm_nattch = 0;
558 shp->shm_file = file;
559 shp->shm_creator = current;
560
561 /*
562 * shmid gets reported as "inode#" in /proc/pid/maps.
563 * proc-ps tools use this. Changing this will break them.
564 */
565 file_inode(file)->i_ino = shp->shm_perm.id;
566
567 ns->shm_tot += numpages;
568 error = shp->shm_perm.id;
569
570 ipc_unlock_object(&shp->shm_perm);
571 rcu_read_unlock();
572 return error;
573
574no_id:
575 if (is_file_hugepages(file) && shp->mlock_user)
576 user_shm_unlock(size, shp->mlock_user);
577 fput(file);
578no_file:
579 ipc_rcu_putref(shp, shm_rcu_free);
580 return error;
581}
582
583/*
584 * Called with shm_ids.rwsem and ipcp locked.
585 */
586static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
587{
588 struct shmid_kernel *shp;
589
590 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
591 return security_shm_associate(shp, shmflg);
592}
593
594/*
595 * Called with shm_ids.rwsem and ipcp locked.
596 */
597static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
598 struct ipc_params *params)
599{
600 struct shmid_kernel *shp;
601
602 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
603 if (shp->shm_segsz < params->u.size)
604 return -EINVAL;
605
606 return 0;
607}
608
609SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
610{
611 struct ipc_namespace *ns;
612 struct ipc_ops shm_ops;
613 struct ipc_params shm_params;
614
615 ns = current->nsproxy->ipc_ns;
616
617 shm_ops.getnew = newseg;
618 shm_ops.associate = shm_security;
619 shm_ops.more_checks = shm_more_checks;
620
621 shm_params.key = key;
622 shm_params.flg = shmflg;
623 shm_params.u.size = size;
624
625 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
626}
627
628static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
629{
630 switch (version) {
631 case IPC_64:
632 return copy_to_user(buf, in, sizeof(*in));
633 case IPC_OLD:
634 {
635 struct shmid_ds out;
636
637 memset(&out, 0, sizeof(out));
638 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
639 out.shm_segsz = in->shm_segsz;
640 out.shm_atime = in->shm_atime;
641 out.shm_dtime = in->shm_dtime;
642 out.shm_ctime = in->shm_ctime;
643 out.shm_cpid = in->shm_cpid;
644 out.shm_lpid = in->shm_lpid;
645 out.shm_nattch = in->shm_nattch;
646
647 return copy_to_user(buf, &out, sizeof(out));
648 }
649 default:
650 return -EINVAL;
651 }
652}
653
654static inline unsigned long
655copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
656{
657 switch (version) {
658 case IPC_64:
659 if (copy_from_user(out, buf, sizeof(*out)))
660 return -EFAULT;
661 return 0;
662 case IPC_OLD:
663 {
664 struct shmid_ds tbuf_old;
665
666 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
667 return -EFAULT;
668
669 out->shm_perm.uid = tbuf_old.shm_perm.uid;
670 out->shm_perm.gid = tbuf_old.shm_perm.gid;
671 out->shm_perm.mode = tbuf_old.shm_perm.mode;
672
673 return 0;
674 }
675 default:
676 return -EINVAL;
677 }
678}
679
680static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
681{
682 switch (version) {
683 case IPC_64:
684 return copy_to_user(buf, in, sizeof(*in));
685 case IPC_OLD:
686 {
687 struct shminfo out;
688
689 if (in->shmmax > INT_MAX)
690 out.shmmax = INT_MAX;
691 else
692 out.shmmax = (int)in->shmmax;
693
694 out.shmmin = in->shmmin;
695 out.shmmni = in->shmmni;
696 out.shmseg = in->shmseg;
697 out.shmall = in->shmall;
698
699 return copy_to_user(buf, &out, sizeof(out));
700 }
701 default:
702 return -EINVAL;
703 }
704}
705
706/*
707 * Calculate and add used RSS and swap pages of a shm.
708 * Called with shm_ids.rwsem held as a reader
709 */
710static void shm_add_rss_swap(struct shmid_kernel *shp,
711 unsigned long *rss_add, unsigned long *swp_add)
712{
713 struct inode *inode;
714
715 inode = file_inode(shp->shm_file);
716
717 if (is_file_hugepages(shp->shm_file)) {
718 struct address_space *mapping = inode->i_mapping;
719 struct hstate *h = hstate_file(shp->shm_file);
720 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
721 } else {
722#ifdef CONFIG_SHMEM
723 struct shmem_inode_info *info = SHMEM_I(inode);
724 spin_lock(&info->lock);
725 *rss_add += inode->i_mapping->nrpages;
726 *swp_add += info->swapped;
727 spin_unlock(&info->lock);
728#else
729 *rss_add += inode->i_mapping->nrpages;
730#endif
731 }
732}
733
734/*
735 * Called with shm_ids.rwsem held as a reader
736 */
737static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
738 unsigned long *swp)
739{
740 int next_id;
741 int total, in_use;
742
743 *rss = 0;
744 *swp = 0;
745
746 in_use = shm_ids(ns).in_use;
747
748 for (total = 0, next_id = 0; total < in_use; next_id++) {
749 struct kern_ipc_perm *ipc;
750 struct shmid_kernel *shp;
751
752 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
753 if (ipc == NULL)
754 continue;
755 shp = container_of(ipc, struct shmid_kernel, shm_perm);
756
757 shm_add_rss_swap(shp, rss, swp);
758
759 total++;
760 }
761}
762
763/*
764 * This function handles some shmctl commands which require the rwsem
765 * to be held in write mode.
766 * NOTE: no locks must be held, the rwsem is taken inside this function.
767 */
768static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
769 struct shmid_ds __user *buf, int version)
770{
771 struct kern_ipc_perm *ipcp;
772 struct shmid64_ds shmid64;
773 struct shmid_kernel *shp;
774 int err;
775
776 if (cmd == IPC_SET) {
777 if (copy_shmid_from_user(&shmid64, buf, version))
778 return -EFAULT;
779 }
780
781 down_write(&shm_ids(ns).rwsem);
782 rcu_read_lock();
783
784 ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
785 &shmid64.shm_perm, 0);
786 if (IS_ERR(ipcp)) {
787 err = PTR_ERR(ipcp);
788 goto out_unlock1;
789 }
790
791 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
792
793 err = security_shm_shmctl(shp, cmd);
794 if (err)
795 goto out_unlock1;
796
797 switch (cmd) {
798 case IPC_RMID:
799 ipc_lock_object(&shp->shm_perm);
800 /* do_shm_rmid unlocks the ipc object and rcu */
801 do_shm_rmid(ns, ipcp);
802 goto out_up;
803 case IPC_SET:
804 ipc_lock_object(&shp->shm_perm);
805 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
806 if (err)
807 goto out_unlock0;
808 shp->shm_ctim = get_seconds();
809 break;
810 default:
811 err = -EINVAL;
812 goto out_unlock1;
813 }
814
815out_unlock0:
816 ipc_unlock_object(&shp->shm_perm);
817out_unlock1:
818 rcu_read_unlock();
819out_up:
820 up_write(&shm_ids(ns).rwsem);
821 return err;
822}
823
824static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
825 int cmd, int version, void __user *buf)
826{
827 int err;
828 struct shmid_kernel *shp;
829
830 /* preliminary security checks for *_INFO */
831 if (cmd == IPC_INFO || cmd == SHM_INFO) {
832 err = security_shm_shmctl(NULL, cmd);
833 if (err)
834 return err;
835 }
836
837 switch (cmd) {
838 case IPC_INFO:
839 {
840 struct shminfo64 shminfo;
841
842 memset(&shminfo, 0, sizeof(shminfo));
843 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
844 shminfo.shmmax = ns->shm_ctlmax;
845 shminfo.shmall = ns->shm_ctlall;
846
847 shminfo.shmmin = SHMMIN;
848 if (copy_shminfo_to_user(buf, &shminfo, version))
849 return -EFAULT;
850
851 down_read(&shm_ids(ns).rwsem);
852 err = ipc_get_maxid(&shm_ids(ns));
853 up_read(&shm_ids(ns).rwsem);
854
855 if (err < 0)
856 err = 0;
857 goto out;
858 }
859 case SHM_INFO:
860 {
861 struct shm_info shm_info;
862
863 memset(&shm_info, 0, sizeof(shm_info));
864 down_read(&shm_ids(ns).rwsem);
865 shm_info.used_ids = shm_ids(ns).in_use;
866 shm_get_stat(ns, &shm_info.shm_rss, &shm_info.shm_swp);
867 shm_info.shm_tot = ns->shm_tot;
868 shm_info.swap_attempts = 0;
869 shm_info.swap_successes = 0;
870 err = ipc_get_maxid(&shm_ids(ns));
871 up_read(&shm_ids(ns).rwsem);
872 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
873 err = -EFAULT;
874 goto out;
875 }
876
877 err = err < 0 ? 0 : err;
878 goto out;
879 }
880 case SHM_STAT:
881 case IPC_STAT:
882 {
883 struct shmid64_ds tbuf;
884 int result;
885
886 rcu_read_lock();
887 if (cmd == SHM_STAT) {
888 shp = shm_obtain_object(ns, shmid);
889 if (IS_ERR(shp)) {
890 err = PTR_ERR(shp);
891 goto out_unlock;
892 }
893 result = shp->shm_perm.id;
894 } else {
895 shp = shm_obtain_object_check(ns, shmid);
896 if (IS_ERR(shp)) {
897 err = PTR_ERR(shp);
898 goto out_unlock;
899 }
900 result = 0;
901 }
902
903 err = -EACCES;
904 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
905 goto out_unlock;
906
907 err = security_shm_shmctl(shp, cmd);
908 if (err)
909 goto out_unlock;
910
911 memset(&tbuf, 0, sizeof(tbuf));
912 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
913 tbuf.shm_segsz = shp->shm_segsz;
914 tbuf.shm_atime = shp->shm_atim;
915 tbuf.shm_dtime = shp->shm_dtim;
916 tbuf.shm_ctime = shp->shm_ctim;
917 tbuf.shm_cpid = shp->shm_cprid;
918 tbuf.shm_lpid = shp->shm_lprid;
919 tbuf.shm_nattch = shp->shm_nattch;
920 rcu_read_unlock();
921
922 if (copy_shmid_to_user(buf, &tbuf, version))
923 err = -EFAULT;
924 else
925 err = result;
926 goto out;
927 }
928 default:
929 return -EINVAL;
930 }
931
932out_unlock:
933 rcu_read_unlock();
934out:
935 return err;
936}
937
938SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
939{
940 struct shmid_kernel *shp;
941 int err, version;
942 struct ipc_namespace *ns;
943
944 if (cmd < 0 || shmid < 0)
945 return -EINVAL;
946
947 version = ipc_parse_version(&cmd);
948 ns = current->nsproxy->ipc_ns;
949
950 switch (cmd) {
951 case IPC_INFO:
952 case SHM_INFO:
953 case SHM_STAT:
954 case IPC_STAT:
955 return shmctl_nolock(ns, shmid, cmd, version, buf);
956 case IPC_RMID:
957 case IPC_SET:
958 return shmctl_down(ns, shmid, cmd, buf, version);
959 case SHM_LOCK:
960 case SHM_UNLOCK:
961 {
962 struct file *shm_file;
963
964 rcu_read_lock();
965 shp = shm_obtain_object_check(ns, shmid);
966 if (IS_ERR(shp)) {
967 err = PTR_ERR(shp);
968 goto out_unlock1;
969 }
970
971 audit_ipc_obj(&(shp->shm_perm));
972 err = security_shm_shmctl(shp, cmd);
973 if (err)
974 goto out_unlock1;
975
976 ipc_lock_object(&shp->shm_perm);
977
978 /* check if shm_destroy() is tearing down shp */
979 if (!ipc_valid_object(&shp->shm_perm)) {
980 err = -EIDRM;
981 goto out_unlock0;
982 }
983
984 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
985 kuid_t euid = current_euid();
986 if (!uid_eq(euid, shp->shm_perm.uid) &&
987 !uid_eq(euid, shp->shm_perm.cuid)) {
988 err = -EPERM;
989 goto out_unlock0;
990 }
991 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
992 err = -EPERM;
993 goto out_unlock0;
994 }
995 }
996
997 shm_file = shp->shm_file;
998 if (is_file_hugepages(shm_file))
999 goto out_unlock0;
1000
1001 if (cmd == SHM_LOCK) {
1002 struct user_struct *user = current_user();
1003 err = shmem_lock(shm_file, 1, user);
1004 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1005 shp->shm_perm.mode |= SHM_LOCKED;
1006 shp->mlock_user = user;
1007 }
1008 goto out_unlock0;
1009 }
1010
1011 /* SHM_UNLOCK */
1012 if (!(shp->shm_perm.mode & SHM_LOCKED))
1013 goto out_unlock0;
1014 shmem_lock(shm_file, 0, shp->mlock_user);
1015 shp->shm_perm.mode &= ~SHM_LOCKED;
1016 shp->mlock_user = NULL;
1017 get_file(shm_file);
1018 ipc_unlock_object(&shp->shm_perm);
1019 rcu_read_unlock();
1020 shmem_unlock_mapping(shm_file->f_mapping);
1021
1022 fput(shm_file);
1023 return err;
1024 }
1025 default:
1026 return -EINVAL;
1027 }
1028
1029out_unlock0:
1030 ipc_unlock_object(&shp->shm_perm);
1031out_unlock1:
1032 rcu_read_unlock();
1033 return err;
1034}
1035
1036/*
1037 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1038 *
1039 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1040 * "raddr" thing points to kernel space, and there has to be a wrapper around
1041 * this.
1042 */
1043long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
1044 unsigned long shmlba)
1045{
1046 struct shmid_kernel *shp;
1047 unsigned long addr;
1048 unsigned long size;
1049 struct file *file;
1050 int err;
1051 unsigned long flags;
1052 unsigned long prot;
1053 int acc_mode;
1054 struct ipc_namespace *ns;
1055 struct shm_file_data *sfd;
1056 struct path path;
1057 fmode_t f_mode;
1058 unsigned long populate = 0;
1059
1060 err = -EINVAL;
1061 if (shmid < 0)
1062 goto out;
1063 else if ((addr = (ulong)shmaddr)) {
1064 if (addr & (shmlba - 1)) {
1065 if (shmflg & SHM_RND)
1066 addr &= ~(shmlba - 1); /* round down */
1067 else
1068#ifndef __ARCH_FORCE_SHMLBA
1069 if (addr & ~PAGE_MASK)
1070#endif
1071 goto out;
1072 }
1073 flags = MAP_SHARED | MAP_FIXED;
1074 } else {
1075 if ((shmflg & SHM_REMAP))
1076 goto out;
1077
1078 flags = MAP_SHARED;
1079 }
1080
1081 if (shmflg & SHM_RDONLY) {
1082 prot = PROT_READ;
1083 acc_mode = S_IRUGO;
1084 f_mode = FMODE_READ;
1085 } else {
1086 prot = PROT_READ | PROT_WRITE;
1087 acc_mode = S_IRUGO | S_IWUGO;
1088 f_mode = FMODE_READ | FMODE_WRITE;
1089 }
1090 if (shmflg & SHM_EXEC) {
1091 prot |= PROT_EXEC;
1092 acc_mode |= S_IXUGO;
1093 }
1094
1095 /*
1096 * We cannot rely on the fs check since SYSV IPC does have an
1097 * additional creator id...
1098 */
1099 ns = current->nsproxy->ipc_ns;
1100 rcu_read_lock();
1101 shp = shm_obtain_object_check(ns, shmid);
1102 if (IS_ERR(shp)) {
1103 err = PTR_ERR(shp);
1104 goto out_unlock;
1105 }
1106
1107 err = -EACCES;
1108 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1109 goto out_unlock;
1110
1111 err = security_shm_shmat(shp, shmaddr, shmflg);
1112 if (err)
1113 goto out_unlock;
1114
1115 ipc_lock_object(&shp->shm_perm);
1116
1117 /* check if shm_destroy() is tearing down shp */
1118 if (!ipc_valid_object(&shp->shm_perm)) {
1119 ipc_unlock_object(&shp->shm_perm);
1120 err = -EIDRM;
1121 goto out_unlock;
1122 }
1123
1124 path = shp->shm_file->f_path;
1125 path_get(&path);
1126 shp->shm_nattch++;
1127 size = i_size_read(path.dentry->d_inode);
1128 ipc_unlock_object(&shp->shm_perm);
1129 rcu_read_unlock();
1130
1131 err = -ENOMEM;
1132 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1133 if (!sfd) {
1134 path_put(&path);
1135 goto out_nattch;
1136 }
1137
1138 file = alloc_file(&path, f_mode,
1139 is_file_hugepages(shp->shm_file) ?
1140 &shm_file_operations_huge :
1141 &shm_file_operations);
1142 err = PTR_ERR(file);
1143 if (IS_ERR(file)) {
1144 kfree(sfd);
1145 path_put(&path);
1146 goto out_nattch;
1147 }
1148
1149 file->private_data = sfd;
1150 file->f_mapping = shp->shm_file->f_mapping;
1151 sfd->id = shp->shm_perm.id;
1152 sfd->ns = get_ipc_ns(ns);
1153 sfd->file = shp->shm_file;
1154 sfd->vm_ops = NULL;
1155
1156 err = security_mmap_file(file, prot, flags);
1157 if (err)
1158 goto out_fput;
1159
1160 down_write(¤t->mm->mmap_sem);
1161 if (addr && !(shmflg & SHM_REMAP)) {
1162 err = -EINVAL;
1163 if (find_vma_intersection(current->mm, addr, addr + size))
1164 goto invalid;
1165 /*
1166 * If shm segment goes below stack, make sure there is some
1167 * space left for the stack to grow (at least 4 pages).
1168 */
1169 if (addr < current->mm->start_stack &&
1170 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1171 goto invalid;
1172 }
1173
1174 addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1175 *raddr = addr;
1176 err = 0;
1177 if (IS_ERR_VALUE(addr))
1178 err = (long)addr;
1179invalid:
1180 up_write(¤t->mm->mmap_sem);
1181 if (populate)
1182 mm_populate(addr, populate);
1183
1184out_fput:
1185 fput(file);
1186
1187out_nattch:
1188 down_write(&shm_ids(ns).rwsem);
1189 shp = shm_lock(ns, shmid);
1190 BUG_ON(IS_ERR(shp));
1191 shp->shm_nattch--;
1192 if (shm_may_destroy(ns, shp))
1193 shm_destroy(ns, shp);
1194 else
1195 shm_unlock(shp);
1196 up_write(&shm_ids(ns).rwsem);
1197 return err;
1198
1199out_unlock:
1200 rcu_read_unlock();
1201out:
1202 return err;
1203}
1204
1205SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1206{
1207 unsigned long ret;
1208 long err;
1209
1210 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1211 if (err)
1212 return err;
1213 force_successful_syscall_return();
1214 return (long)ret;
1215}
1216
1217/*
1218 * detach and kill segment if marked destroyed.
1219 * The work is done in shm_close.
1220 */
1221SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1222{
1223 struct mm_struct *mm = current->mm;
1224 struct vm_area_struct *vma;
1225 unsigned long addr = (unsigned long)shmaddr;
1226 int retval = -EINVAL;
1227#ifdef CONFIG_MMU
1228 loff_t size = 0;
1229 struct vm_area_struct *next;
1230#endif
1231
1232 if (addr & ~PAGE_MASK)
1233 return retval;
1234
1235 down_write(&mm->mmap_sem);
1236
1237 /*
1238 * This function tries to be smart and unmap shm segments that
1239 * were modified by partial mlock or munmap calls:
1240 * - It first determines the size of the shm segment that should be
1241 * unmapped: It searches for a vma that is backed by shm and that
1242 * started at address shmaddr. It records it's size and then unmaps
1243 * it.
1244 * - Then it unmaps all shm vmas that started at shmaddr and that
1245 * are within the initially determined size.
1246 * Errors from do_munmap are ignored: the function only fails if
1247 * it's called with invalid parameters or if it's called to unmap
1248 * a part of a vma. Both calls in this function are for full vmas,
1249 * the parameters are directly copied from the vma itself and always
1250 * valid - therefore do_munmap cannot fail. (famous last words?)
1251 */
1252 /*
1253 * If it had been mremap()'d, the starting address would not
1254 * match the usual checks anyway. So assume all vma's are
1255 * above the starting address given.
1256 */
1257 vma = find_vma(mm, addr);
1258
1259#ifdef CONFIG_MMU
1260 while (vma) {
1261 next = vma->vm_next;
1262
1263 /*
1264 * Check if the starting address would match, i.e. it's
1265 * a fragment created by mprotect() and/or munmap(), or it
1266 * otherwise it starts at this address with no hassles.
1267 */
1268 if ((vma->vm_ops == &shm_vm_ops) &&
1269 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1270
1271
1272 size = file_inode(vma->vm_file)->i_size;
1273 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1274 /*
1275 * We discovered the size of the shm segment, so
1276 * break out of here and fall through to the next
1277 * loop that uses the size information to stop
1278 * searching for matching vma's.
1279 */
1280 retval = 0;
1281 vma = next;
1282 break;
1283 }
1284 vma = next;
1285 }
1286
1287 /*
1288 * We need look no further than the maximum address a fragment
1289 * could possibly have landed at. Also cast things to loff_t to
1290 * prevent overflows and make comparisons vs. equal-width types.
1291 */
1292 size = PAGE_ALIGN(size);
1293 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1294 next = vma->vm_next;
1295
1296 /* finding a matching vma now does not alter retval */
1297 if ((vma->vm_ops == &shm_vm_ops) &&
1298 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1299
1300 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1301 vma = next;
1302 }
1303
1304#else /* CONFIG_MMU */
1305 /* under NOMMU conditions, the exact address to be destroyed must be
1306 * given */
1307 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1308 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1309 retval = 0;
1310 }
1311
1312#endif
1313
1314 up_write(&mm->mmap_sem);
1315 return retval;
1316}
1317
1318#ifdef CONFIG_PROC_FS
1319static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1320{
1321 struct user_namespace *user_ns = seq_user_ns(s);
1322 struct shmid_kernel *shp = it;
1323 unsigned long rss = 0, swp = 0;
1324
1325 shm_add_rss_swap(shp, &rss, &swp);
1326
1327#if BITS_PER_LONG <= 32
1328#define SIZE_SPEC "%10lu"
1329#else
1330#define SIZE_SPEC "%21lu"
1331#endif
1332
1333 return seq_printf(s,
1334 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1335 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1336 SIZE_SPEC " " SIZE_SPEC "\n",
1337 shp->shm_perm.key,
1338 shp->shm_perm.id,
1339 shp->shm_perm.mode,
1340 shp->shm_segsz,
1341 shp->shm_cprid,
1342 shp->shm_lprid,
1343 shp->shm_nattch,
1344 from_kuid_munged(user_ns, shp->shm_perm.uid),
1345 from_kgid_munged(user_ns, shp->shm_perm.gid),
1346 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1347 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1348 shp->shm_atim,
1349 shp->shm_dtim,
1350 shp->shm_ctim,
1351 rss * PAGE_SIZE,
1352 swp * PAGE_SIZE);
1353}
1354#endif
1/*
2 * linux/ipc/shm.c
3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
4 * Many improvements/fixes by Bruno Haible.
5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
7 *
8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
15 *
16 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
18 *
19 * namespaces support
20 * OpenVZ, SWsoft Inc.
21 * Pavel Emelianov <xemul@openvz.org>
22 */
23
24#include <linux/slab.h>
25#include <linux/mm.h>
26#include <linux/hugetlb.h>
27#include <linux/shm.h>
28#include <linux/init.h>
29#include <linux/file.h>
30#include <linux/mman.h>
31#include <linux/shmem_fs.h>
32#include <linux/security.h>
33#include <linux/syscalls.h>
34#include <linux/audit.h>
35#include <linux/capability.h>
36#include <linux/ptrace.h>
37#include <linux/seq_file.h>
38#include <linux/rwsem.h>
39#include <linux/nsproxy.h>
40#include <linux/mount.h>
41#include <linux/ipc_namespace.h>
42
43#include <asm/uaccess.h>
44
45#include "util.h"
46
47struct shm_file_data {
48 int id;
49 struct ipc_namespace *ns;
50 struct file *file;
51 const struct vm_operations_struct *vm_ops;
52};
53
54#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
55
56static const struct file_operations shm_file_operations;
57static const struct vm_operations_struct shm_vm_ops;
58
59#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
60
61#define shm_unlock(shp) \
62 ipc_unlock(&(shp)->shm_perm)
63
64static int newseg(struct ipc_namespace *, struct ipc_params *);
65static void shm_open(struct vm_area_struct *vma);
66static void shm_close(struct vm_area_struct *vma);
67static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
68#ifdef CONFIG_PROC_FS
69static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
70#endif
71
72void shm_init_ns(struct ipc_namespace *ns)
73{
74 ns->shm_ctlmax = SHMMAX;
75 ns->shm_ctlall = SHMALL;
76 ns->shm_ctlmni = SHMMNI;
77 ns->shm_rmid_forced = 0;
78 ns->shm_tot = 0;
79 ipc_init_ids(&shm_ids(ns));
80}
81
82/*
83 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
84 * Only shm_ids.rw_mutex remains locked on exit.
85 */
86static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
87{
88 struct shmid_kernel *shp;
89 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
90
91 if (shp->shm_nattch){
92 shp->shm_perm.mode |= SHM_DEST;
93 /* Do not find it any more */
94 shp->shm_perm.key = IPC_PRIVATE;
95 shm_unlock(shp);
96 } else
97 shm_destroy(ns, shp);
98}
99
100#ifdef CONFIG_IPC_NS
101void shm_exit_ns(struct ipc_namespace *ns)
102{
103 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
104 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
105}
106#endif
107
108static int __init ipc_ns_init(void)
109{
110 shm_init_ns(&init_ipc_ns);
111 return 0;
112}
113
114pure_initcall(ipc_ns_init);
115
116void __init shm_init (void)
117{
118 ipc_init_proc_interface("sysvipc/shm",
119#if BITS_PER_LONG <= 32
120 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
121#else
122 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
123#endif
124 IPC_SHM_IDS, sysvipc_shm_proc_show);
125}
126
127/*
128 * shm_lock_(check_) routines are called in the paths where the rw_mutex
129 * is not necessarily held.
130 */
131static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
132{
133 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
134
135 if (IS_ERR(ipcp))
136 return (struct shmid_kernel *)ipcp;
137
138 return container_of(ipcp, struct shmid_kernel, shm_perm);
139}
140
141static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
142{
143 rcu_read_lock();
144 spin_lock(&ipcp->shm_perm.lock);
145}
146
147static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
148 int id)
149{
150 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
151
152 if (IS_ERR(ipcp))
153 return (struct shmid_kernel *)ipcp;
154
155 return container_of(ipcp, struct shmid_kernel, shm_perm);
156}
157
158static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
159{
160 ipc_rmid(&shm_ids(ns), &s->shm_perm);
161}
162
163
164/* This is called by fork, once for every shm attach. */
165static void shm_open(struct vm_area_struct *vma)
166{
167 struct file *file = vma->vm_file;
168 struct shm_file_data *sfd = shm_file_data(file);
169 struct shmid_kernel *shp;
170
171 shp = shm_lock(sfd->ns, sfd->id);
172 BUG_ON(IS_ERR(shp));
173 shp->shm_atim = get_seconds();
174 shp->shm_lprid = task_tgid_vnr(current);
175 shp->shm_nattch++;
176 shm_unlock(shp);
177}
178
179/*
180 * shm_destroy - free the struct shmid_kernel
181 *
182 * @ns: namespace
183 * @shp: struct to free
184 *
185 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
186 * but returns with shp unlocked and freed.
187 */
188static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
189{
190 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
191 shm_rmid(ns, shp);
192 shm_unlock(shp);
193 if (!is_file_hugepages(shp->shm_file))
194 shmem_lock(shp->shm_file, 0, shp->mlock_user);
195 else if (shp->mlock_user)
196 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
197 shp->mlock_user);
198 fput (shp->shm_file);
199 security_shm_free(shp);
200 ipc_rcu_putref(shp);
201}
202
203/*
204 * shm_may_destroy - identifies whether shm segment should be destroyed now
205 *
206 * Returns true if and only if there are no active users of the segment and
207 * one of the following is true:
208 *
209 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
210 *
211 * 2) sysctl kernel.shm_rmid_forced is set to 1.
212 */
213static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
214{
215 return (shp->shm_nattch == 0) &&
216 (ns->shm_rmid_forced ||
217 (shp->shm_perm.mode & SHM_DEST));
218}
219
220/*
221 * remove the attach descriptor vma.
222 * free memory for segment if it is marked destroyed.
223 * The descriptor has already been removed from the current->mm->mmap list
224 * and will later be kfree()d.
225 */
226static void shm_close(struct vm_area_struct *vma)
227{
228 struct file * file = vma->vm_file;
229 struct shm_file_data *sfd = shm_file_data(file);
230 struct shmid_kernel *shp;
231 struct ipc_namespace *ns = sfd->ns;
232
233 down_write(&shm_ids(ns).rw_mutex);
234 /* remove from the list of attaches of the shm segment */
235 shp = shm_lock(ns, sfd->id);
236 BUG_ON(IS_ERR(shp));
237 shp->shm_lprid = task_tgid_vnr(current);
238 shp->shm_dtim = get_seconds();
239 shp->shm_nattch--;
240 if (shm_may_destroy(ns, shp))
241 shm_destroy(ns, shp);
242 else
243 shm_unlock(shp);
244 up_write(&shm_ids(ns).rw_mutex);
245}
246
247/* Called with ns->shm_ids(ns).rw_mutex locked */
248static int shm_try_destroy_current(int id, void *p, void *data)
249{
250 struct ipc_namespace *ns = data;
251 struct kern_ipc_perm *ipcp = p;
252 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
253
254 if (shp->shm_creator != current)
255 return 0;
256
257 /*
258 * Mark it as orphaned to destroy the segment when
259 * kernel.shm_rmid_forced is changed.
260 * It is noop if the following shm_may_destroy() returns true.
261 */
262 shp->shm_creator = NULL;
263
264 /*
265 * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID
266 * is not set, it shouldn't be deleted here.
267 */
268 if (!ns->shm_rmid_forced)
269 return 0;
270
271 if (shm_may_destroy(ns, shp)) {
272 shm_lock_by_ptr(shp);
273 shm_destroy(ns, shp);
274 }
275 return 0;
276}
277
278/* Called with ns->shm_ids(ns).rw_mutex locked */
279static int shm_try_destroy_orphaned(int id, void *p, void *data)
280{
281 struct ipc_namespace *ns = data;
282 struct kern_ipc_perm *ipcp = p;
283 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
284
285 /*
286 * We want to destroy segments without users and with already
287 * exit'ed originating process.
288 *
289 * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
290 */
291 if (shp->shm_creator != NULL)
292 return 0;
293
294 if (shm_may_destroy(ns, shp)) {
295 shm_lock_by_ptr(shp);
296 shm_destroy(ns, shp);
297 }
298 return 0;
299}
300
301void shm_destroy_orphaned(struct ipc_namespace *ns)
302{
303 down_write(&shm_ids(ns).rw_mutex);
304 if (shm_ids(ns).in_use)
305 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
306 up_write(&shm_ids(ns).rw_mutex);
307}
308
309
310void exit_shm(struct task_struct *task)
311{
312 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
313
314 if (shm_ids(ns).in_use == 0)
315 return;
316
317 /* Destroy all already created segments, but not mapped yet */
318 down_write(&shm_ids(ns).rw_mutex);
319 if (shm_ids(ns).in_use)
320 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
321 up_write(&shm_ids(ns).rw_mutex);
322}
323
324static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
325{
326 struct file *file = vma->vm_file;
327 struct shm_file_data *sfd = shm_file_data(file);
328
329 return sfd->vm_ops->fault(vma, vmf);
330}
331
332#ifdef CONFIG_NUMA
333static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
334{
335 struct file *file = vma->vm_file;
336 struct shm_file_data *sfd = shm_file_data(file);
337 int err = 0;
338 if (sfd->vm_ops->set_policy)
339 err = sfd->vm_ops->set_policy(vma, new);
340 return err;
341}
342
343static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
344 unsigned long addr)
345{
346 struct file *file = vma->vm_file;
347 struct shm_file_data *sfd = shm_file_data(file);
348 struct mempolicy *pol = NULL;
349
350 if (sfd->vm_ops->get_policy)
351 pol = sfd->vm_ops->get_policy(vma, addr);
352 else if (vma->vm_policy)
353 pol = vma->vm_policy;
354
355 return pol;
356}
357#endif
358
359static int shm_mmap(struct file * file, struct vm_area_struct * vma)
360{
361 struct shm_file_data *sfd = shm_file_data(file);
362 int ret;
363
364 ret = sfd->file->f_op->mmap(sfd->file, vma);
365 if (ret != 0)
366 return ret;
367 sfd->vm_ops = vma->vm_ops;
368#ifdef CONFIG_MMU
369 BUG_ON(!sfd->vm_ops->fault);
370#endif
371 vma->vm_ops = &shm_vm_ops;
372 shm_open(vma);
373
374 return ret;
375}
376
377static int shm_release(struct inode *ino, struct file *file)
378{
379 struct shm_file_data *sfd = shm_file_data(file);
380
381 put_ipc_ns(sfd->ns);
382 shm_file_data(file) = NULL;
383 kfree(sfd);
384 return 0;
385}
386
387static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
388{
389 struct shm_file_data *sfd = shm_file_data(file);
390
391 if (!sfd->file->f_op->fsync)
392 return -EINVAL;
393 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
394}
395
396static unsigned long shm_get_unmapped_area(struct file *file,
397 unsigned long addr, unsigned long len, unsigned long pgoff,
398 unsigned long flags)
399{
400 struct shm_file_data *sfd = shm_file_data(file);
401 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
402 pgoff, flags);
403}
404
405static const struct file_operations shm_file_operations = {
406 .mmap = shm_mmap,
407 .fsync = shm_fsync,
408 .release = shm_release,
409#ifndef CONFIG_MMU
410 .get_unmapped_area = shm_get_unmapped_area,
411#endif
412 .llseek = noop_llseek,
413};
414
415static const struct file_operations shm_file_operations_huge = {
416 .mmap = shm_mmap,
417 .fsync = shm_fsync,
418 .release = shm_release,
419 .get_unmapped_area = shm_get_unmapped_area,
420 .llseek = noop_llseek,
421};
422
423int is_file_shm_hugepages(struct file *file)
424{
425 return file->f_op == &shm_file_operations_huge;
426}
427
428static const struct vm_operations_struct shm_vm_ops = {
429 .open = shm_open, /* callback for a new vm-area open */
430 .close = shm_close, /* callback for when the vm-area is released */
431 .fault = shm_fault,
432#if defined(CONFIG_NUMA)
433 .set_policy = shm_set_policy,
434 .get_policy = shm_get_policy,
435#endif
436};
437
438/**
439 * newseg - Create a new shared memory segment
440 * @ns: namespace
441 * @params: ptr to the structure that contains key, size and shmflg
442 *
443 * Called with shm_ids.rw_mutex held as a writer.
444 */
445
446static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
447{
448 key_t key = params->key;
449 int shmflg = params->flg;
450 size_t size = params->u.size;
451 int error;
452 struct shmid_kernel *shp;
453 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
454 struct file * file;
455 char name[13];
456 int id;
457 vm_flags_t acctflag = 0;
458
459 if (size < SHMMIN || size > ns->shm_ctlmax)
460 return -EINVAL;
461
462 if (ns->shm_tot + numpages > ns->shm_ctlall)
463 return -ENOSPC;
464
465 shp = ipc_rcu_alloc(sizeof(*shp));
466 if (!shp)
467 return -ENOMEM;
468
469 shp->shm_perm.key = key;
470 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
471 shp->mlock_user = NULL;
472
473 shp->shm_perm.security = NULL;
474 error = security_shm_alloc(shp);
475 if (error) {
476 ipc_rcu_putref(shp);
477 return error;
478 }
479
480 sprintf (name, "SYSV%08x", key);
481 if (shmflg & SHM_HUGETLB) {
482 /* hugetlb_file_setup applies strict accounting */
483 if (shmflg & SHM_NORESERVE)
484 acctflag = VM_NORESERVE;
485 file = hugetlb_file_setup(name, size, acctflag,
486 &shp->mlock_user, HUGETLB_SHMFS_INODE);
487 } else {
488 /*
489 * Do not allow no accounting for OVERCOMMIT_NEVER, even
490 * if it's asked for.
491 */
492 if ((shmflg & SHM_NORESERVE) &&
493 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
494 acctflag = VM_NORESERVE;
495 file = shmem_file_setup(name, size, acctflag);
496 }
497 error = PTR_ERR(file);
498 if (IS_ERR(file))
499 goto no_file;
500
501 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
502 if (id < 0) {
503 error = id;
504 goto no_id;
505 }
506
507 shp->shm_cprid = task_tgid_vnr(current);
508 shp->shm_lprid = 0;
509 shp->shm_atim = shp->shm_dtim = 0;
510 shp->shm_ctim = get_seconds();
511 shp->shm_segsz = size;
512 shp->shm_nattch = 0;
513 shp->shm_file = file;
514 shp->shm_creator = current;
515 /*
516 * shmid gets reported as "inode#" in /proc/pid/maps.
517 * proc-ps tools use this. Changing this will break them.
518 */
519 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
520
521 ns->shm_tot += numpages;
522 error = shp->shm_perm.id;
523 shm_unlock(shp);
524 return error;
525
526no_id:
527 if (is_file_hugepages(file) && shp->mlock_user)
528 user_shm_unlock(size, shp->mlock_user);
529 fput(file);
530no_file:
531 security_shm_free(shp);
532 ipc_rcu_putref(shp);
533 return error;
534}
535
536/*
537 * Called with shm_ids.rw_mutex and ipcp locked.
538 */
539static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
540{
541 struct shmid_kernel *shp;
542
543 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
544 return security_shm_associate(shp, shmflg);
545}
546
547/*
548 * Called with shm_ids.rw_mutex and ipcp locked.
549 */
550static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
551 struct ipc_params *params)
552{
553 struct shmid_kernel *shp;
554
555 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
556 if (shp->shm_segsz < params->u.size)
557 return -EINVAL;
558
559 return 0;
560}
561
562SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
563{
564 struct ipc_namespace *ns;
565 struct ipc_ops shm_ops;
566 struct ipc_params shm_params;
567
568 ns = current->nsproxy->ipc_ns;
569
570 shm_ops.getnew = newseg;
571 shm_ops.associate = shm_security;
572 shm_ops.more_checks = shm_more_checks;
573
574 shm_params.key = key;
575 shm_params.flg = shmflg;
576 shm_params.u.size = size;
577
578 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
579}
580
581static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
582{
583 switch(version) {
584 case IPC_64:
585 return copy_to_user(buf, in, sizeof(*in));
586 case IPC_OLD:
587 {
588 struct shmid_ds out;
589
590 memset(&out, 0, sizeof(out));
591 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
592 out.shm_segsz = in->shm_segsz;
593 out.shm_atime = in->shm_atime;
594 out.shm_dtime = in->shm_dtime;
595 out.shm_ctime = in->shm_ctime;
596 out.shm_cpid = in->shm_cpid;
597 out.shm_lpid = in->shm_lpid;
598 out.shm_nattch = in->shm_nattch;
599
600 return copy_to_user(buf, &out, sizeof(out));
601 }
602 default:
603 return -EINVAL;
604 }
605}
606
607static inline unsigned long
608copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
609{
610 switch(version) {
611 case IPC_64:
612 if (copy_from_user(out, buf, sizeof(*out)))
613 return -EFAULT;
614 return 0;
615 case IPC_OLD:
616 {
617 struct shmid_ds tbuf_old;
618
619 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
620 return -EFAULT;
621
622 out->shm_perm.uid = tbuf_old.shm_perm.uid;
623 out->shm_perm.gid = tbuf_old.shm_perm.gid;
624 out->shm_perm.mode = tbuf_old.shm_perm.mode;
625
626 return 0;
627 }
628 default:
629 return -EINVAL;
630 }
631}
632
633static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
634{
635 switch(version) {
636 case IPC_64:
637 return copy_to_user(buf, in, sizeof(*in));
638 case IPC_OLD:
639 {
640 struct shminfo out;
641
642 if(in->shmmax > INT_MAX)
643 out.shmmax = INT_MAX;
644 else
645 out.shmmax = (int)in->shmmax;
646
647 out.shmmin = in->shmmin;
648 out.shmmni = in->shmmni;
649 out.shmseg = in->shmseg;
650 out.shmall = in->shmall;
651
652 return copy_to_user(buf, &out, sizeof(out));
653 }
654 default:
655 return -EINVAL;
656 }
657}
658
659/*
660 * Calculate and add used RSS and swap pages of a shm.
661 * Called with shm_ids.rw_mutex held as a reader
662 */
663static void shm_add_rss_swap(struct shmid_kernel *shp,
664 unsigned long *rss_add, unsigned long *swp_add)
665{
666 struct inode *inode;
667
668 inode = shp->shm_file->f_path.dentry->d_inode;
669
670 if (is_file_hugepages(shp->shm_file)) {
671 struct address_space *mapping = inode->i_mapping;
672 struct hstate *h = hstate_file(shp->shm_file);
673 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
674 } else {
675#ifdef CONFIG_SHMEM
676 struct shmem_inode_info *info = SHMEM_I(inode);
677 spin_lock(&info->lock);
678 *rss_add += inode->i_mapping->nrpages;
679 *swp_add += info->swapped;
680 spin_unlock(&info->lock);
681#else
682 *rss_add += inode->i_mapping->nrpages;
683#endif
684 }
685}
686
687/*
688 * Called with shm_ids.rw_mutex held as a reader
689 */
690static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
691 unsigned long *swp)
692{
693 int next_id;
694 int total, in_use;
695
696 *rss = 0;
697 *swp = 0;
698
699 in_use = shm_ids(ns).in_use;
700
701 for (total = 0, next_id = 0; total < in_use; next_id++) {
702 struct kern_ipc_perm *ipc;
703 struct shmid_kernel *shp;
704
705 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
706 if (ipc == NULL)
707 continue;
708 shp = container_of(ipc, struct shmid_kernel, shm_perm);
709
710 shm_add_rss_swap(shp, rss, swp);
711
712 total++;
713 }
714}
715
716/*
717 * This function handles some shmctl commands which require the rw_mutex
718 * to be held in write mode.
719 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
720 */
721static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
722 struct shmid_ds __user *buf, int version)
723{
724 struct kern_ipc_perm *ipcp;
725 struct shmid64_ds shmid64;
726 struct shmid_kernel *shp;
727 int err;
728
729 if (cmd == IPC_SET) {
730 if (copy_shmid_from_user(&shmid64, buf, version))
731 return -EFAULT;
732 }
733
734 ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
735 &shmid64.shm_perm, 0);
736 if (IS_ERR(ipcp))
737 return PTR_ERR(ipcp);
738
739 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
740
741 err = security_shm_shmctl(shp, cmd);
742 if (err)
743 goto out_unlock;
744 switch (cmd) {
745 case IPC_RMID:
746 do_shm_rmid(ns, ipcp);
747 goto out_up;
748 case IPC_SET:
749 ipc_update_perm(&shmid64.shm_perm, ipcp);
750 shp->shm_ctim = get_seconds();
751 break;
752 default:
753 err = -EINVAL;
754 }
755out_unlock:
756 shm_unlock(shp);
757out_up:
758 up_write(&shm_ids(ns).rw_mutex);
759 return err;
760}
761
762SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
763{
764 struct shmid_kernel *shp;
765 int err, version;
766 struct ipc_namespace *ns;
767
768 if (cmd < 0 || shmid < 0) {
769 err = -EINVAL;
770 goto out;
771 }
772
773 version = ipc_parse_version(&cmd);
774 ns = current->nsproxy->ipc_ns;
775
776 switch (cmd) { /* replace with proc interface ? */
777 case IPC_INFO:
778 {
779 struct shminfo64 shminfo;
780
781 err = security_shm_shmctl(NULL, cmd);
782 if (err)
783 return err;
784
785 memset(&shminfo, 0, sizeof(shminfo));
786 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
787 shminfo.shmmax = ns->shm_ctlmax;
788 shminfo.shmall = ns->shm_ctlall;
789
790 shminfo.shmmin = SHMMIN;
791 if(copy_shminfo_to_user (buf, &shminfo, version))
792 return -EFAULT;
793
794 down_read(&shm_ids(ns).rw_mutex);
795 err = ipc_get_maxid(&shm_ids(ns));
796 up_read(&shm_ids(ns).rw_mutex);
797
798 if(err<0)
799 err = 0;
800 goto out;
801 }
802 case SHM_INFO:
803 {
804 struct shm_info shm_info;
805
806 err = security_shm_shmctl(NULL, cmd);
807 if (err)
808 return err;
809
810 memset(&shm_info, 0, sizeof(shm_info));
811 down_read(&shm_ids(ns).rw_mutex);
812 shm_info.used_ids = shm_ids(ns).in_use;
813 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
814 shm_info.shm_tot = ns->shm_tot;
815 shm_info.swap_attempts = 0;
816 shm_info.swap_successes = 0;
817 err = ipc_get_maxid(&shm_ids(ns));
818 up_read(&shm_ids(ns).rw_mutex);
819 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
820 err = -EFAULT;
821 goto out;
822 }
823
824 err = err < 0 ? 0 : err;
825 goto out;
826 }
827 case SHM_STAT:
828 case IPC_STAT:
829 {
830 struct shmid64_ds tbuf;
831 int result;
832
833 if (cmd == SHM_STAT) {
834 shp = shm_lock(ns, shmid);
835 if (IS_ERR(shp)) {
836 err = PTR_ERR(shp);
837 goto out;
838 }
839 result = shp->shm_perm.id;
840 } else {
841 shp = shm_lock_check(ns, shmid);
842 if (IS_ERR(shp)) {
843 err = PTR_ERR(shp);
844 goto out;
845 }
846 result = 0;
847 }
848 err = -EACCES;
849 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
850 goto out_unlock;
851 err = security_shm_shmctl(shp, cmd);
852 if (err)
853 goto out_unlock;
854 memset(&tbuf, 0, sizeof(tbuf));
855 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
856 tbuf.shm_segsz = shp->shm_segsz;
857 tbuf.shm_atime = shp->shm_atim;
858 tbuf.shm_dtime = shp->shm_dtim;
859 tbuf.shm_ctime = shp->shm_ctim;
860 tbuf.shm_cpid = shp->shm_cprid;
861 tbuf.shm_lpid = shp->shm_lprid;
862 tbuf.shm_nattch = shp->shm_nattch;
863 shm_unlock(shp);
864 if(copy_shmid_to_user (buf, &tbuf, version))
865 err = -EFAULT;
866 else
867 err = result;
868 goto out;
869 }
870 case SHM_LOCK:
871 case SHM_UNLOCK:
872 {
873 struct file *uninitialized_var(shm_file);
874
875 lru_add_drain_all(); /* drain pagevecs to lru lists */
876
877 shp = shm_lock_check(ns, shmid);
878 if (IS_ERR(shp)) {
879 err = PTR_ERR(shp);
880 goto out;
881 }
882
883 audit_ipc_obj(&(shp->shm_perm));
884
885 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
886 uid_t euid = current_euid();
887 err = -EPERM;
888 if (euid != shp->shm_perm.uid &&
889 euid != shp->shm_perm.cuid)
890 goto out_unlock;
891 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
892 goto out_unlock;
893 }
894
895 err = security_shm_shmctl(shp, cmd);
896 if (err)
897 goto out_unlock;
898
899 if(cmd==SHM_LOCK) {
900 struct user_struct *user = current_user();
901 if (!is_file_hugepages(shp->shm_file)) {
902 err = shmem_lock(shp->shm_file, 1, user);
903 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
904 shp->shm_perm.mode |= SHM_LOCKED;
905 shp->mlock_user = user;
906 }
907 }
908 } else if (!is_file_hugepages(shp->shm_file)) {
909 shmem_lock(shp->shm_file, 0, shp->mlock_user);
910 shp->shm_perm.mode &= ~SHM_LOCKED;
911 shp->mlock_user = NULL;
912 }
913 shm_unlock(shp);
914 goto out;
915 }
916 case IPC_RMID:
917 case IPC_SET:
918 err = shmctl_down(ns, shmid, cmd, buf, version);
919 return err;
920 default:
921 return -EINVAL;
922 }
923
924out_unlock:
925 shm_unlock(shp);
926out:
927 return err;
928}
929
930/*
931 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
932 *
933 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
934 * "raddr" thing points to kernel space, and there has to be a wrapper around
935 * this.
936 */
937long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
938{
939 struct shmid_kernel *shp;
940 unsigned long addr;
941 unsigned long size;
942 struct file * file;
943 int err;
944 unsigned long flags;
945 unsigned long prot;
946 int acc_mode;
947 unsigned long user_addr;
948 struct ipc_namespace *ns;
949 struct shm_file_data *sfd;
950 struct path path;
951 fmode_t f_mode;
952
953 err = -EINVAL;
954 if (shmid < 0)
955 goto out;
956 else if ((addr = (ulong)shmaddr)) {
957 if (addr & (SHMLBA-1)) {
958 if (shmflg & SHM_RND)
959 addr &= ~(SHMLBA-1); /* round down */
960 else
961#ifndef __ARCH_FORCE_SHMLBA
962 if (addr & ~PAGE_MASK)
963#endif
964 goto out;
965 }
966 flags = MAP_SHARED | MAP_FIXED;
967 } else {
968 if ((shmflg & SHM_REMAP))
969 goto out;
970
971 flags = MAP_SHARED;
972 }
973
974 if (shmflg & SHM_RDONLY) {
975 prot = PROT_READ;
976 acc_mode = S_IRUGO;
977 f_mode = FMODE_READ;
978 } else {
979 prot = PROT_READ | PROT_WRITE;
980 acc_mode = S_IRUGO | S_IWUGO;
981 f_mode = FMODE_READ | FMODE_WRITE;
982 }
983 if (shmflg & SHM_EXEC) {
984 prot |= PROT_EXEC;
985 acc_mode |= S_IXUGO;
986 }
987
988 /*
989 * We cannot rely on the fs check since SYSV IPC does have an
990 * additional creator id...
991 */
992 ns = current->nsproxy->ipc_ns;
993 shp = shm_lock_check(ns, shmid);
994 if (IS_ERR(shp)) {
995 err = PTR_ERR(shp);
996 goto out;
997 }
998
999 err = -EACCES;
1000 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1001 goto out_unlock;
1002
1003 err = security_shm_shmat(shp, shmaddr, shmflg);
1004 if (err)
1005 goto out_unlock;
1006
1007 path = shp->shm_file->f_path;
1008 path_get(&path);
1009 shp->shm_nattch++;
1010 size = i_size_read(path.dentry->d_inode);
1011 shm_unlock(shp);
1012
1013 err = -ENOMEM;
1014 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1015 if (!sfd)
1016 goto out_put_dentry;
1017
1018 file = alloc_file(&path, f_mode,
1019 is_file_hugepages(shp->shm_file) ?
1020 &shm_file_operations_huge :
1021 &shm_file_operations);
1022 if (!file)
1023 goto out_free;
1024
1025 file->private_data = sfd;
1026 file->f_mapping = shp->shm_file->f_mapping;
1027 sfd->id = shp->shm_perm.id;
1028 sfd->ns = get_ipc_ns(ns);
1029 sfd->file = shp->shm_file;
1030 sfd->vm_ops = NULL;
1031
1032 down_write(¤t->mm->mmap_sem);
1033 if (addr && !(shmflg & SHM_REMAP)) {
1034 err = -EINVAL;
1035 if (find_vma_intersection(current->mm, addr, addr + size))
1036 goto invalid;
1037 /*
1038 * If shm segment goes below stack, make sure there is some
1039 * space left for the stack to grow (at least 4 pages).
1040 */
1041 if (addr < current->mm->start_stack &&
1042 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1043 goto invalid;
1044 }
1045
1046 user_addr = do_mmap (file, addr, size, prot, flags, 0);
1047 *raddr = user_addr;
1048 err = 0;
1049 if (IS_ERR_VALUE(user_addr))
1050 err = (long)user_addr;
1051invalid:
1052 up_write(¤t->mm->mmap_sem);
1053
1054 fput(file);
1055
1056out_nattch:
1057 down_write(&shm_ids(ns).rw_mutex);
1058 shp = shm_lock(ns, shmid);
1059 BUG_ON(IS_ERR(shp));
1060 shp->shm_nattch--;
1061 if (shm_may_destroy(ns, shp))
1062 shm_destroy(ns, shp);
1063 else
1064 shm_unlock(shp);
1065 up_write(&shm_ids(ns).rw_mutex);
1066
1067out:
1068 return err;
1069
1070out_unlock:
1071 shm_unlock(shp);
1072 goto out;
1073
1074out_free:
1075 kfree(sfd);
1076out_put_dentry:
1077 path_put(&path);
1078 goto out_nattch;
1079}
1080
1081SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1082{
1083 unsigned long ret;
1084 long err;
1085
1086 err = do_shmat(shmid, shmaddr, shmflg, &ret);
1087 if (err)
1088 return err;
1089 force_successful_syscall_return();
1090 return (long)ret;
1091}
1092
1093/*
1094 * detach and kill segment if marked destroyed.
1095 * The work is done in shm_close.
1096 */
1097SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1098{
1099 struct mm_struct *mm = current->mm;
1100 struct vm_area_struct *vma;
1101 unsigned long addr = (unsigned long)shmaddr;
1102 int retval = -EINVAL;
1103#ifdef CONFIG_MMU
1104 loff_t size = 0;
1105 struct vm_area_struct *next;
1106#endif
1107
1108 if (addr & ~PAGE_MASK)
1109 return retval;
1110
1111 down_write(&mm->mmap_sem);
1112
1113 /*
1114 * This function tries to be smart and unmap shm segments that
1115 * were modified by partial mlock or munmap calls:
1116 * - It first determines the size of the shm segment that should be
1117 * unmapped: It searches for a vma that is backed by shm and that
1118 * started at address shmaddr. It records it's size and then unmaps
1119 * it.
1120 * - Then it unmaps all shm vmas that started at shmaddr and that
1121 * are within the initially determined size.
1122 * Errors from do_munmap are ignored: the function only fails if
1123 * it's called with invalid parameters or if it's called to unmap
1124 * a part of a vma. Both calls in this function are for full vmas,
1125 * the parameters are directly copied from the vma itself and always
1126 * valid - therefore do_munmap cannot fail. (famous last words?)
1127 */
1128 /*
1129 * If it had been mremap()'d, the starting address would not
1130 * match the usual checks anyway. So assume all vma's are
1131 * above the starting address given.
1132 */
1133 vma = find_vma(mm, addr);
1134
1135#ifdef CONFIG_MMU
1136 while (vma) {
1137 next = vma->vm_next;
1138
1139 /*
1140 * Check if the starting address would match, i.e. it's
1141 * a fragment created by mprotect() and/or munmap(), or it
1142 * otherwise it starts at this address with no hassles.
1143 */
1144 if ((vma->vm_ops == &shm_vm_ops) &&
1145 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1146
1147
1148 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1149 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1150 /*
1151 * We discovered the size of the shm segment, so
1152 * break out of here and fall through to the next
1153 * loop that uses the size information to stop
1154 * searching for matching vma's.
1155 */
1156 retval = 0;
1157 vma = next;
1158 break;
1159 }
1160 vma = next;
1161 }
1162
1163 /*
1164 * We need look no further than the maximum address a fragment
1165 * could possibly have landed at. Also cast things to loff_t to
1166 * prevent overflows and make comparisons vs. equal-width types.
1167 */
1168 size = PAGE_ALIGN(size);
1169 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1170 next = vma->vm_next;
1171
1172 /* finding a matching vma now does not alter retval */
1173 if ((vma->vm_ops == &shm_vm_ops) &&
1174 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1175
1176 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1177 vma = next;
1178 }
1179
1180#else /* CONFIG_MMU */
1181 /* under NOMMU conditions, the exact address to be destroyed must be
1182 * given */
1183 retval = -EINVAL;
1184 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1185 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1186 retval = 0;
1187 }
1188
1189#endif
1190
1191 up_write(&mm->mmap_sem);
1192 return retval;
1193}
1194
1195#ifdef CONFIG_PROC_FS
1196static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1197{
1198 struct shmid_kernel *shp = it;
1199 unsigned long rss = 0, swp = 0;
1200
1201 shm_add_rss_swap(shp, &rss, &swp);
1202
1203#if BITS_PER_LONG <= 32
1204#define SIZE_SPEC "%10lu"
1205#else
1206#define SIZE_SPEC "%21lu"
1207#endif
1208
1209 return seq_printf(s,
1210 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1211 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1212 SIZE_SPEC " " SIZE_SPEC "\n",
1213 shp->shm_perm.key,
1214 shp->shm_perm.id,
1215 shp->shm_perm.mode,
1216 shp->shm_segsz,
1217 shp->shm_cprid,
1218 shp->shm_lprid,
1219 shp->shm_nattch,
1220 shp->shm_perm.uid,
1221 shp->shm_perm.gid,
1222 shp->shm_perm.cuid,
1223 shp->shm_perm.cgid,
1224 shp->shm_atim,
1225 shp->shm_dtim,
1226 shp->shm_ctim,
1227 rss * PAGE_SIZE,
1228 swp * PAGE_SIZE);
1229}
1230#endif