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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 * 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 <linux/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_idr(&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 /*
159 * Callers of shm_lock() must validate the status of the returned ipc
160 * object pointer (as returned by ipc_lock()), and error out as
161 * appropriate.
162 */
163 if (IS_ERR(ipcp))
164 return (void *)ipcp;
165 return container_of(ipcp, struct shmid_kernel, shm_perm);
166}
167
168static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
169{
170 rcu_read_lock();
171 ipc_lock_object(&ipcp->shm_perm);
172}
173
174static void shm_rcu_free(struct rcu_head *head)
175{
176 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
177 struct shmid_kernel *shp = ipc_rcu_to_struct(p);
178
179 security_shm_free(shp);
180 ipc_rcu_free(head);
181}
182
183static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
184{
185 list_del(&s->shm_clist);
186 ipc_rmid(&shm_ids(ns), &s->shm_perm);
187}
188
189
190static int __shm_open(struct vm_area_struct *vma)
191{
192 struct file *file = vma->vm_file;
193 struct shm_file_data *sfd = shm_file_data(file);
194 struct shmid_kernel *shp;
195
196 shp = shm_lock(sfd->ns, sfd->id);
197
198 if (IS_ERR(shp))
199 return PTR_ERR(shp);
200
201 shp->shm_atim = get_seconds();
202 shp->shm_lprid = task_tgid_vnr(current);
203 shp->shm_nattch++;
204 shm_unlock(shp);
205 return 0;
206}
207
208/* This is called by fork, once for every shm attach. */
209static void shm_open(struct vm_area_struct *vma)
210{
211 int err = __shm_open(vma);
212 /*
213 * We raced in the idr lookup or with shm_destroy().
214 * Either way, the ID is busted.
215 */
216 WARN_ON_ONCE(err);
217}
218
219/*
220 * shm_destroy - free the struct shmid_kernel
221 *
222 * @ns: namespace
223 * @shp: struct to free
224 *
225 * It has to be called with shp and shm_ids.rwsem (writer) locked,
226 * but returns with shp unlocked and freed.
227 */
228static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
229{
230 struct file *shm_file;
231
232 shm_file = shp->shm_file;
233 shp->shm_file = NULL;
234 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
235 shm_rmid(ns, shp);
236 shm_unlock(shp);
237 if (!is_file_hugepages(shm_file))
238 shmem_lock(shm_file, 0, shp->mlock_user);
239 else if (shp->mlock_user)
240 user_shm_unlock(i_size_read(file_inode(shm_file)),
241 shp->mlock_user);
242 fput(shm_file);
243 ipc_rcu_putref(shp, shm_rcu_free);
244}
245
246/*
247 * shm_may_destroy - identifies whether shm segment should be destroyed now
248 *
249 * Returns true if and only if there are no active users of the segment and
250 * one of the following is true:
251 *
252 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
253 *
254 * 2) sysctl kernel.shm_rmid_forced is set to 1.
255 */
256static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
257{
258 return (shp->shm_nattch == 0) &&
259 (ns->shm_rmid_forced ||
260 (shp->shm_perm.mode & SHM_DEST));
261}
262
263/*
264 * remove the attach descriptor vma.
265 * free memory for segment if it is marked destroyed.
266 * The descriptor has already been removed from the current->mm->mmap list
267 * and will later be kfree()d.
268 */
269static void shm_close(struct vm_area_struct *vma)
270{
271 struct file *file = vma->vm_file;
272 struct shm_file_data *sfd = shm_file_data(file);
273 struct shmid_kernel *shp;
274 struct ipc_namespace *ns = sfd->ns;
275
276 down_write(&shm_ids(ns).rwsem);
277 /* remove from the list of attaches of the shm segment */
278 shp = shm_lock(ns, sfd->id);
279
280 /*
281 * We raced in the idr lookup or with shm_destroy().
282 * Either way, the ID is busted.
283 */
284 if (WARN_ON_ONCE(IS_ERR(shp)))
285 goto done; /* no-op */
286
287 shp->shm_lprid = task_tgid_vnr(current);
288 shp->shm_dtim = get_seconds();
289 shp->shm_nattch--;
290 if (shm_may_destroy(ns, shp))
291 shm_destroy(ns, shp);
292 else
293 shm_unlock(shp);
294done:
295 up_write(&shm_ids(ns).rwsem);
296}
297
298/* Called with ns->shm_ids(ns).rwsem locked */
299static int shm_try_destroy_orphaned(int id, void *p, void *data)
300{
301 struct ipc_namespace *ns = data;
302 struct kern_ipc_perm *ipcp = p;
303 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
304
305 /*
306 * We want to destroy segments without users and with already
307 * exit'ed originating process.
308 *
309 * As shp->* are changed under rwsem, it's safe to skip shp locking.
310 */
311 if (shp->shm_creator != NULL)
312 return 0;
313
314 if (shm_may_destroy(ns, shp)) {
315 shm_lock_by_ptr(shp);
316 shm_destroy(ns, shp);
317 }
318 return 0;
319}
320
321void shm_destroy_orphaned(struct ipc_namespace *ns)
322{
323 down_write(&shm_ids(ns).rwsem);
324 if (shm_ids(ns).in_use)
325 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
326 up_write(&shm_ids(ns).rwsem);
327}
328
329/* Locking assumes this will only be called with task == current */
330void exit_shm(struct task_struct *task)
331{
332 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
333 struct shmid_kernel *shp, *n;
334
335 if (list_empty(&task->sysvshm.shm_clist))
336 return;
337
338 /*
339 * If kernel.shm_rmid_forced is not set then only keep track of
340 * which shmids are orphaned, so that a later set of the sysctl
341 * can clean them up.
342 */
343 if (!ns->shm_rmid_forced) {
344 down_read(&shm_ids(ns).rwsem);
345 list_for_each_entry(shp, &task->sysvshm.shm_clist, shm_clist)
346 shp->shm_creator = NULL;
347 /*
348 * Only under read lock but we are only called on current
349 * so no entry on the list will be shared.
350 */
351 list_del(&task->sysvshm.shm_clist);
352 up_read(&shm_ids(ns).rwsem);
353 return;
354 }
355
356 /*
357 * Destroy all already created segments, that were not yet mapped,
358 * and mark any mapped as orphan to cover the sysctl toggling.
359 * Destroy is skipped if shm_may_destroy() returns false.
360 */
361 down_write(&shm_ids(ns).rwsem);
362 list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) {
363 shp->shm_creator = NULL;
364
365 if (shm_may_destroy(ns, shp)) {
366 shm_lock_by_ptr(shp);
367 shm_destroy(ns, shp);
368 }
369 }
370
371 /* Remove the list head from any segments still attached. */
372 list_del(&task->sysvshm.shm_clist);
373 up_write(&shm_ids(ns).rwsem);
374}
375
376static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
377{
378 struct file *file = vma->vm_file;
379 struct shm_file_data *sfd = shm_file_data(file);
380
381 return sfd->vm_ops->fault(vma, vmf);
382}
383
384#ifdef CONFIG_NUMA
385static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
386{
387 struct file *file = vma->vm_file;
388 struct shm_file_data *sfd = shm_file_data(file);
389 int err = 0;
390 if (sfd->vm_ops->set_policy)
391 err = sfd->vm_ops->set_policy(vma, new);
392 return err;
393}
394
395static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
396 unsigned long addr)
397{
398 struct file *file = vma->vm_file;
399 struct shm_file_data *sfd = shm_file_data(file);
400 struct mempolicy *pol = NULL;
401
402 if (sfd->vm_ops->get_policy)
403 pol = sfd->vm_ops->get_policy(vma, addr);
404 else if (vma->vm_policy)
405 pol = vma->vm_policy;
406
407 return pol;
408}
409#endif
410
411static int shm_mmap(struct file *file, struct vm_area_struct *vma)
412{
413 struct shm_file_data *sfd = shm_file_data(file);
414 int ret;
415
416 /*
417 * In case of remap_file_pages() emulation, the file can represent
418 * removed IPC ID: propogate shm_lock() error to caller.
419 */
420 ret =__shm_open(vma);
421 if (ret)
422 return ret;
423
424 ret = sfd->file->f_op->mmap(sfd->file, vma);
425 if (ret) {
426 shm_close(vma);
427 return ret;
428 }
429 sfd->vm_ops = vma->vm_ops;
430#ifdef CONFIG_MMU
431 WARN_ON(!sfd->vm_ops->fault);
432#endif
433 vma->vm_ops = &shm_vm_ops;
434 return 0;
435}
436
437static int shm_release(struct inode *ino, struct file *file)
438{
439 struct shm_file_data *sfd = shm_file_data(file);
440
441 put_ipc_ns(sfd->ns);
442 shm_file_data(file) = NULL;
443 kfree(sfd);
444 return 0;
445}
446
447static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
448{
449 struct shm_file_data *sfd = shm_file_data(file);
450
451 if (!sfd->file->f_op->fsync)
452 return -EINVAL;
453 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
454}
455
456static long shm_fallocate(struct file *file, int mode, loff_t offset,
457 loff_t len)
458{
459 struct shm_file_data *sfd = shm_file_data(file);
460
461 if (!sfd->file->f_op->fallocate)
462 return -EOPNOTSUPP;
463 return sfd->file->f_op->fallocate(file, mode, offset, len);
464}
465
466static unsigned long shm_get_unmapped_area(struct file *file,
467 unsigned long addr, unsigned long len, unsigned long pgoff,
468 unsigned long flags)
469{
470 struct shm_file_data *sfd = shm_file_data(file);
471 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
472 pgoff, flags);
473}
474
475static const struct file_operations shm_file_operations = {
476 .mmap = shm_mmap,
477 .fsync = shm_fsync,
478 .release = shm_release,
479#ifndef CONFIG_MMU
480 .get_unmapped_area = shm_get_unmapped_area,
481#endif
482 .llseek = noop_llseek,
483 .fallocate = shm_fallocate,
484};
485
486static const struct file_operations shm_file_operations_huge = {
487 .mmap = shm_mmap,
488 .fsync = shm_fsync,
489 .release = shm_release,
490 .get_unmapped_area = shm_get_unmapped_area,
491 .llseek = noop_llseek,
492 .fallocate = shm_fallocate,
493};
494
495bool is_file_shm_hugepages(struct file *file)
496{
497 return file->f_op == &shm_file_operations_huge;
498}
499
500static const struct vm_operations_struct shm_vm_ops = {
501 .open = shm_open, /* callback for a new vm-area open */
502 .close = shm_close, /* callback for when the vm-area is released */
503 .fault = shm_fault,
504#if defined(CONFIG_NUMA)
505 .set_policy = shm_set_policy,
506 .get_policy = shm_get_policy,
507#endif
508};
509
510/**
511 * newseg - Create a new shared memory segment
512 * @ns: namespace
513 * @params: ptr to the structure that contains key, size and shmflg
514 *
515 * Called with shm_ids.rwsem held as a writer.
516 */
517static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
518{
519 key_t key = params->key;
520 int shmflg = params->flg;
521 size_t size = params->u.size;
522 int error;
523 struct shmid_kernel *shp;
524 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
525 struct file *file;
526 char name[13];
527 int id;
528 vm_flags_t acctflag = 0;
529
530 if (size < SHMMIN || size > ns->shm_ctlmax)
531 return -EINVAL;
532
533 if (numpages << PAGE_SHIFT < size)
534 return -ENOSPC;
535
536 if (ns->shm_tot + numpages < ns->shm_tot ||
537 ns->shm_tot + numpages > ns->shm_ctlall)
538 return -ENOSPC;
539
540 shp = ipc_rcu_alloc(sizeof(*shp));
541 if (!shp)
542 return -ENOMEM;
543
544 shp->shm_perm.key = key;
545 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
546 shp->mlock_user = NULL;
547
548 shp->shm_perm.security = NULL;
549 error = security_shm_alloc(shp);
550 if (error) {
551 ipc_rcu_putref(shp, ipc_rcu_free);
552 return error;
553 }
554
555 sprintf(name, "SYSV%08x", key);
556 if (shmflg & SHM_HUGETLB) {
557 struct hstate *hs;
558 size_t hugesize;
559
560 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
561 if (!hs) {
562 error = -EINVAL;
563 goto no_file;
564 }
565 hugesize = ALIGN(size, huge_page_size(hs));
566
567 /* hugetlb_file_setup applies strict accounting */
568 if (shmflg & SHM_NORESERVE)
569 acctflag = VM_NORESERVE;
570 file = hugetlb_file_setup(name, hugesize, acctflag,
571 &shp->mlock_user, HUGETLB_SHMFS_INODE,
572 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
573 } else {
574 /*
575 * Do not allow no accounting for OVERCOMMIT_NEVER, even
576 * if it's asked for.
577 */
578 if ((shmflg & SHM_NORESERVE) &&
579 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
580 acctflag = VM_NORESERVE;
581 file = shmem_kernel_file_setup(name, size, acctflag);
582 }
583 error = PTR_ERR(file);
584 if (IS_ERR(file))
585 goto no_file;
586
587 shp->shm_cprid = task_tgid_vnr(current);
588 shp->shm_lprid = 0;
589 shp->shm_atim = shp->shm_dtim = 0;
590 shp->shm_ctim = get_seconds();
591 shp->shm_segsz = size;
592 shp->shm_nattch = 0;
593 shp->shm_file = file;
594 shp->shm_creator = current;
595
596 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
597 if (id < 0) {
598 error = id;
599 goto no_id;
600 }
601
602 list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist);
603
604 /*
605 * shmid gets reported as "inode#" in /proc/pid/maps.
606 * proc-ps tools use this. Changing this will break them.
607 */
608 file_inode(file)->i_ino = shp->shm_perm.id;
609
610 ns->shm_tot += numpages;
611 error = shp->shm_perm.id;
612
613 ipc_unlock_object(&shp->shm_perm);
614 rcu_read_unlock();
615 return error;
616
617no_id:
618 if (is_file_hugepages(file) && shp->mlock_user)
619 user_shm_unlock(size, shp->mlock_user);
620 fput(file);
621no_file:
622 ipc_rcu_putref(shp, shm_rcu_free);
623 return error;
624}
625
626/*
627 * Called with shm_ids.rwsem and ipcp locked.
628 */
629static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
630{
631 struct shmid_kernel *shp;
632
633 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
634 return security_shm_associate(shp, shmflg);
635}
636
637/*
638 * Called with shm_ids.rwsem and ipcp locked.
639 */
640static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
641 struct ipc_params *params)
642{
643 struct shmid_kernel *shp;
644
645 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
646 if (shp->shm_segsz < params->u.size)
647 return -EINVAL;
648
649 return 0;
650}
651
652SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
653{
654 struct ipc_namespace *ns;
655 static const struct ipc_ops shm_ops = {
656 .getnew = newseg,
657 .associate = shm_security,
658 .more_checks = shm_more_checks,
659 };
660 struct ipc_params shm_params;
661
662 ns = current->nsproxy->ipc_ns;
663
664 shm_params.key = key;
665 shm_params.flg = shmflg;
666 shm_params.u.size = size;
667
668 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
669}
670
671static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
672{
673 switch (version) {
674 case IPC_64:
675 return copy_to_user(buf, in, sizeof(*in));
676 case IPC_OLD:
677 {
678 struct shmid_ds out;
679
680 memset(&out, 0, sizeof(out));
681 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
682 out.shm_segsz = in->shm_segsz;
683 out.shm_atime = in->shm_atime;
684 out.shm_dtime = in->shm_dtime;
685 out.shm_ctime = in->shm_ctime;
686 out.shm_cpid = in->shm_cpid;
687 out.shm_lpid = in->shm_lpid;
688 out.shm_nattch = in->shm_nattch;
689
690 return copy_to_user(buf, &out, sizeof(out));
691 }
692 default:
693 return -EINVAL;
694 }
695}
696
697static inline unsigned long
698copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
699{
700 switch (version) {
701 case IPC_64:
702 if (copy_from_user(out, buf, sizeof(*out)))
703 return -EFAULT;
704 return 0;
705 case IPC_OLD:
706 {
707 struct shmid_ds tbuf_old;
708
709 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
710 return -EFAULT;
711
712 out->shm_perm.uid = tbuf_old.shm_perm.uid;
713 out->shm_perm.gid = tbuf_old.shm_perm.gid;
714 out->shm_perm.mode = tbuf_old.shm_perm.mode;
715
716 return 0;
717 }
718 default:
719 return -EINVAL;
720 }
721}
722
723static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
724{
725 switch (version) {
726 case IPC_64:
727 return copy_to_user(buf, in, sizeof(*in));
728 case IPC_OLD:
729 {
730 struct shminfo out;
731
732 if (in->shmmax > INT_MAX)
733 out.shmmax = INT_MAX;
734 else
735 out.shmmax = (int)in->shmmax;
736
737 out.shmmin = in->shmmin;
738 out.shmmni = in->shmmni;
739 out.shmseg = in->shmseg;
740 out.shmall = in->shmall;
741
742 return copy_to_user(buf, &out, sizeof(out));
743 }
744 default:
745 return -EINVAL;
746 }
747}
748
749/*
750 * Calculate and add used RSS and swap pages of a shm.
751 * Called with shm_ids.rwsem held as a reader
752 */
753static void shm_add_rss_swap(struct shmid_kernel *shp,
754 unsigned long *rss_add, unsigned long *swp_add)
755{
756 struct inode *inode;
757
758 inode = file_inode(shp->shm_file);
759
760 if (is_file_hugepages(shp->shm_file)) {
761 struct address_space *mapping = inode->i_mapping;
762 struct hstate *h = hstate_file(shp->shm_file);
763 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
764 } else {
765#ifdef CONFIG_SHMEM
766 struct shmem_inode_info *info = SHMEM_I(inode);
767 spin_lock(&info->lock);
768 *rss_add += inode->i_mapping->nrpages;
769 *swp_add += info->swapped;
770 spin_unlock(&info->lock);
771#else
772 *rss_add += inode->i_mapping->nrpages;
773#endif
774 }
775}
776
777/*
778 * Called with shm_ids.rwsem held as a reader
779 */
780static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
781 unsigned long *swp)
782{
783 int next_id;
784 int total, in_use;
785
786 *rss = 0;
787 *swp = 0;
788
789 in_use = shm_ids(ns).in_use;
790
791 for (total = 0, next_id = 0; total < in_use; next_id++) {
792 struct kern_ipc_perm *ipc;
793 struct shmid_kernel *shp;
794
795 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
796 if (ipc == NULL)
797 continue;
798 shp = container_of(ipc, struct shmid_kernel, shm_perm);
799
800 shm_add_rss_swap(shp, rss, swp);
801
802 total++;
803 }
804}
805
806/*
807 * This function handles some shmctl commands which require the rwsem
808 * to be held in write mode.
809 * NOTE: no locks must be held, the rwsem is taken inside this function.
810 */
811static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
812 struct shmid_ds __user *buf, int version)
813{
814 struct kern_ipc_perm *ipcp;
815 struct shmid64_ds shmid64;
816 struct shmid_kernel *shp;
817 int err;
818
819 if (cmd == IPC_SET) {
820 if (copy_shmid_from_user(&shmid64, buf, version))
821 return -EFAULT;
822 }
823
824 down_write(&shm_ids(ns).rwsem);
825 rcu_read_lock();
826
827 ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
828 &shmid64.shm_perm, 0);
829 if (IS_ERR(ipcp)) {
830 err = PTR_ERR(ipcp);
831 goto out_unlock1;
832 }
833
834 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
835
836 err = security_shm_shmctl(shp, cmd);
837 if (err)
838 goto out_unlock1;
839
840 switch (cmd) {
841 case IPC_RMID:
842 ipc_lock_object(&shp->shm_perm);
843 /* do_shm_rmid unlocks the ipc object and rcu */
844 do_shm_rmid(ns, ipcp);
845 goto out_up;
846 case IPC_SET:
847 ipc_lock_object(&shp->shm_perm);
848 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
849 if (err)
850 goto out_unlock0;
851 shp->shm_ctim = get_seconds();
852 break;
853 default:
854 err = -EINVAL;
855 goto out_unlock1;
856 }
857
858out_unlock0:
859 ipc_unlock_object(&shp->shm_perm);
860out_unlock1:
861 rcu_read_unlock();
862out_up:
863 up_write(&shm_ids(ns).rwsem);
864 return err;
865}
866
867static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
868 int cmd, int version, void __user *buf)
869{
870 int err;
871 struct shmid_kernel *shp;
872
873 /* preliminary security checks for *_INFO */
874 if (cmd == IPC_INFO || cmd == SHM_INFO) {
875 err = security_shm_shmctl(NULL, cmd);
876 if (err)
877 return err;
878 }
879
880 switch (cmd) {
881 case IPC_INFO:
882 {
883 struct shminfo64 shminfo;
884
885 memset(&shminfo, 0, sizeof(shminfo));
886 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
887 shminfo.shmmax = ns->shm_ctlmax;
888 shminfo.shmall = ns->shm_ctlall;
889
890 shminfo.shmmin = SHMMIN;
891 if (copy_shminfo_to_user(buf, &shminfo, version))
892 return -EFAULT;
893
894 down_read(&shm_ids(ns).rwsem);
895 err = ipc_get_maxid(&shm_ids(ns));
896 up_read(&shm_ids(ns).rwsem);
897
898 if (err < 0)
899 err = 0;
900 goto out;
901 }
902 case SHM_INFO:
903 {
904 struct shm_info shm_info;
905
906 memset(&shm_info, 0, sizeof(shm_info));
907 down_read(&shm_ids(ns).rwsem);
908 shm_info.used_ids = shm_ids(ns).in_use;
909 shm_get_stat(ns, &shm_info.shm_rss, &shm_info.shm_swp);
910 shm_info.shm_tot = ns->shm_tot;
911 shm_info.swap_attempts = 0;
912 shm_info.swap_successes = 0;
913 err = ipc_get_maxid(&shm_ids(ns));
914 up_read(&shm_ids(ns).rwsem);
915 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
916 err = -EFAULT;
917 goto out;
918 }
919
920 err = err < 0 ? 0 : err;
921 goto out;
922 }
923 case SHM_STAT:
924 case IPC_STAT:
925 {
926 struct shmid64_ds tbuf;
927 int result;
928
929 rcu_read_lock();
930 if (cmd == SHM_STAT) {
931 shp = shm_obtain_object(ns, shmid);
932 if (IS_ERR(shp)) {
933 err = PTR_ERR(shp);
934 goto out_unlock;
935 }
936 result = shp->shm_perm.id;
937 } else {
938 shp = shm_obtain_object_check(ns, shmid);
939 if (IS_ERR(shp)) {
940 err = PTR_ERR(shp);
941 goto out_unlock;
942 }
943 result = 0;
944 }
945
946 err = -EACCES;
947 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
948 goto out_unlock;
949
950 err = security_shm_shmctl(shp, cmd);
951 if (err)
952 goto out_unlock;
953
954 memset(&tbuf, 0, sizeof(tbuf));
955 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
956 tbuf.shm_segsz = shp->shm_segsz;
957 tbuf.shm_atime = shp->shm_atim;
958 tbuf.shm_dtime = shp->shm_dtim;
959 tbuf.shm_ctime = shp->shm_ctim;
960 tbuf.shm_cpid = shp->shm_cprid;
961 tbuf.shm_lpid = shp->shm_lprid;
962 tbuf.shm_nattch = shp->shm_nattch;
963 rcu_read_unlock();
964
965 if (copy_shmid_to_user(buf, &tbuf, version))
966 err = -EFAULT;
967 else
968 err = result;
969 goto out;
970 }
971 default:
972 return -EINVAL;
973 }
974
975out_unlock:
976 rcu_read_unlock();
977out:
978 return err;
979}
980
981SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
982{
983 struct shmid_kernel *shp;
984 int err, version;
985 struct ipc_namespace *ns;
986
987 if (cmd < 0 || shmid < 0)
988 return -EINVAL;
989
990 version = ipc_parse_version(&cmd);
991 ns = current->nsproxy->ipc_ns;
992
993 switch (cmd) {
994 case IPC_INFO:
995 case SHM_INFO:
996 case SHM_STAT:
997 case IPC_STAT:
998 return shmctl_nolock(ns, shmid, cmd, version, buf);
999 case IPC_RMID:
1000 case IPC_SET:
1001 return shmctl_down(ns, shmid, cmd, buf, version);
1002 case SHM_LOCK:
1003 case SHM_UNLOCK:
1004 {
1005 struct file *shm_file;
1006
1007 rcu_read_lock();
1008 shp = shm_obtain_object_check(ns, shmid);
1009 if (IS_ERR(shp)) {
1010 err = PTR_ERR(shp);
1011 goto out_unlock1;
1012 }
1013
1014 audit_ipc_obj(&(shp->shm_perm));
1015 err = security_shm_shmctl(shp, cmd);
1016 if (err)
1017 goto out_unlock1;
1018
1019 ipc_lock_object(&shp->shm_perm);
1020
1021 /* check if shm_destroy() is tearing down shp */
1022 if (!ipc_valid_object(&shp->shm_perm)) {
1023 err = -EIDRM;
1024 goto out_unlock0;
1025 }
1026
1027 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
1028 kuid_t euid = current_euid();
1029 if (!uid_eq(euid, shp->shm_perm.uid) &&
1030 !uid_eq(euid, shp->shm_perm.cuid)) {
1031 err = -EPERM;
1032 goto out_unlock0;
1033 }
1034 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1035 err = -EPERM;
1036 goto out_unlock0;
1037 }
1038 }
1039
1040 shm_file = shp->shm_file;
1041 if (is_file_hugepages(shm_file))
1042 goto out_unlock0;
1043
1044 if (cmd == SHM_LOCK) {
1045 struct user_struct *user = current_user();
1046 err = shmem_lock(shm_file, 1, user);
1047 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1048 shp->shm_perm.mode |= SHM_LOCKED;
1049 shp->mlock_user = user;
1050 }
1051 goto out_unlock0;
1052 }
1053
1054 /* SHM_UNLOCK */
1055 if (!(shp->shm_perm.mode & SHM_LOCKED))
1056 goto out_unlock0;
1057 shmem_lock(shm_file, 0, shp->mlock_user);
1058 shp->shm_perm.mode &= ~SHM_LOCKED;
1059 shp->mlock_user = NULL;
1060 get_file(shm_file);
1061 ipc_unlock_object(&shp->shm_perm);
1062 rcu_read_unlock();
1063 shmem_unlock_mapping(shm_file->f_mapping);
1064
1065 fput(shm_file);
1066 return err;
1067 }
1068 default:
1069 return -EINVAL;
1070 }
1071
1072out_unlock0:
1073 ipc_unlock_object(&shp->shm_perm);
1074out_unlock1:
1075 rcu_read_unlock();
1076 return err;
1077}
1078
1079/*
1080 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1081 *
1082 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1083 * "raddr" thing points to kernel space, and there has to be a wrapper around
1084 * this.
1085 */
1086long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
1087 unsigned long shmlba)
1088{
1089 struct shmid_kernel *shp;
1090 unsigned long addr;
1091 unsigned long size;
1092 struct file *file;
1093 int err;
1094 unsigned long flags;
1095 unsigned long prot;
1096 int acc_mode;
1097 struct ipc_namespace *ns;
1098 struct shm_file_data *sfd;
1099 struct path path;
1100 fmode_t f_mode;
1101 unsigned long populate = 0;
1102
1103 err = -EINVAL;
1104 if (shmid < 0)
1105 goto out;
1106 else if ((addr = (ulong)shmaddr)) {
1107 if (addr & (shmlba - 1)) {
1108 if (shmflg & SHM_RND)
1109 addr &= ~(shmlba - 1); /* round down */
1110 else
1111#ifndef __ARCH_FORCE_SHMLBA
1112 if (addr & ~PAGE_MASK)
1113#endif
1114 goto out;
1115 }
1116 flags = MAP_SHARED | MAP_FIXED;
1117 } else {
1118 if ((shmflg & SHM_REMAP))
1119 goto out;
1120
1121 flags = MAP_SHARED;
1122 }
1123
1124 if (shmflg & SHM_RDONLY) {
1125 prot = PROT_READ;
1126 acc_mode = S_IRUGO;
1127 f_mode = FMODE_READ;
1128 } else {
1129 prot = PROT_READ | PROT_WRITE;
1130 acc_mode = S_IRUGO | S_IWUGO;
1131 f_mode = FMODE_READ | FMODE_WRITE;
1132 }
1133 if (shmflg & SHM_EXEC) {
1134 prot |= PROT_EXEC;
1135 acc_mode |= S_IXUGO;
1136 }
1137
1138 /*
1139 * We cannot rely on the fs check since SYSV IPC does have an
1140 * additional creator id...
1141 */
1142 ns = current->nsproxy->ipc_ns;
1143 rcu_read_lock();
1144 shp = shm_obtain_object_check(ns, shmid);
1145 if (IS_ERR(shp)) {
1146 err = PTR_ERR(shp);
1147 goto out_unlock;
1148 }
1149
1150 err = -EACCES;
1151 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1152 goto out_unlock;
1153
1154 err = security_shm_shmat(shp, shmaddr, shmflg);
1155 if (err)
1156 goto out_unlock;
1157
1158 ipc_lock_object(&shp->shm_perm);
1159
1160 /* check if shm_destroy() is tearing down shp */
1161 if (!ipc_valid_object(&shp->shm_perm)) {
1162 ipc_unlock_object(&shp->shm_perm);
1163 err = -EIDRM;
1164 goto out_unlock;
1165 }
1166
1167 path = shp->shm_file->f_path;
1168 path_get(&path);
1169 shp->shm_nattch++;
1170 size = i_size_read(d_inode(path.dentry));
1171 ipc_unlock_object(&shp->shm_perm);
1172 rcu_read_unlock();
1173
1174 err = -ENOMEM;
1175 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1176 if (!sfd) {
1177 path_put(&path);
1178 goto out_nattch;
1179 }
1180
1181 file = alloc_file(&path, f_mode,
1182 is_file_hugepages(shp->shm_file) ?
1183 &shm_file_operations_huge :
1184 &shm_file_operations);
1185 err = PTR_ERR(file);
1186 if (IS_ERR(file)) {
1187 kfree(sfd);
1188 path_put(&path);
1189 goto out_nattch;
1190 }
1191
1192 file->private_data = sfd;
1193 file->f_mapping = shp->shm_file->f_mapping;
1194 sfd->id = shp->shm_perm.id;
1195 sfd->ns = get_ipc_ns(ns);
1196 sfd->file = shp->shm_file;
1197 sfd->vm_ops = NULL;
1198
1199 err = security_mmap_file(file, prot, flags);
1200 if (err)
1201 goto out_fput;
1202
1203 down_write(¤t->mm->mmap_sem);
1204 if (addr && !(shmflg & SHM_REMAP)) {
1205 err = -EINVAL;
1206 if (addr + size < addr)
1207 goto invalid;
1208
1209 if (find_vma_intersection(current->mm, addr, addr + size))
1210 goto invalid;
1211 }
1212
1213 addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1214 *raddr = addr;
1215 err = 0;
1216 if (IS_ERR_VALUE(addr))
1217 err = (long)addr;
1218invalid:
1219 up_write(¤t->mm->mmap_sem);
1220 if (populate)
1221 mm_populate(addr, populate);
1222
1223out_fput:
1224 fput(file);
1225
1226out_nattch:
1227 down_write(&shm_ids(ns).rwsem);
1228 shp = shm_lock(ns, shmid);
1229 shp->shm_nattch--;
1230 if (shm_may_destroy(ns, shp))
1231 shm_destroy(ns, shp);
1232 else
1233 shm_unlock(shp);
1234 up_write(&shm_ids(ns).rwsem);
1235 return err;
1236
1237out_unlock:
1238 rcu_read_unlock();
1239out:
1240 return err;
1241}
1242
1243SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1244{
1245 unsigned long ret;
1246 long err;
1247
1248 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1249 if (err)
1250 return err;
1251 force_successful_syscall_return();
1252 return (long)ret;
1253}
1254
1255/*
1256 * detach and kill segment if marked destroyed.
1257 * The work is done in shm_close.
1258 */
1259SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1260{
1261 struct mm_struct *mm = current->mm;
1262 struct vm_area_struct *vma;
1263 unsigned long addr = (unsigned long)shmaddr;
1264 int retval = -EINVAL;
1265#ifdef CONFIG_MMU
1266 loff_t size = 0;
1267 struct file *file;
1268 struct vm_area_struct *next;
1269#endif
1270
1271 if (addr & ~PAGE_MASK)
1272 return retval;
1273
1274 down_write(&mm->mmap_sem);
1275
1276 /*
1277 * This function tries to be smart and unmap shm segments that
1278 * were modified by partial mlock or munmap calls:
1279 * - It first determines the size of the shm segment that should be
1280 * unmapped: It searches for a vma that is backed by shm and that
1281 * started at address shmaddr. It records it's size and then unmaps
1282 * it.
1283 * - Then it unmaps all shm vmas that started at shmaddr and that
1284 * are within the initially determined size and that are from the
1285 * same shm segment from which we determined the size.
1286 * Errors from do_munmap are ignored: the function only fails if
1287 * it's called with invalid parameters or if it's called to unmap
1288 * a part of a vma. Both calls in this function are for full vmas,
1289 * the parameters are directly copied from the vma itself and always
1290 * valid - therefore do_munmap cannot fail. (famous last words?)
1291 */
1292 /*
1293 * If it had been mremap()'d, the starting address would not
1294 * match the usual checks anyway. So assume all vma's are
1295 * above the starting address given.
1296 */
1297 vma = find_vma(mm, addr);
1298
1299#ifdef CONFIG_MMU
1300 while (vma) {
1301 next = vma->vm_next;
1302
1303 /*
1304 * Check if the starting address would match, i.e. it's
1305 * a fragment created by mprotect() and/or munmap(), or it
1306 * otherwise it starts at this address with no hassles.
1307 */
1308 if ((vma->vm_ops == &shm_vm_ops) &&
1309 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1310
1311 /*
1312 * Record the file of the shm segment being
1313 * unmapped. With mremap(), someone could place
1314 * page from another segment but with equal offsets
1315 * in the range we are unmapping.
1316 */
1317 file = vma->vm_file;
1318 size = i_size_read(file_inode(vma->vm_file));
1319 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1320 /*
1321 * We discovered the size of the shm segment, so
1322 * break out of here and fall through to the next
1323 * loop that uses the size information to stop
1324 * searching for matching vma's.
1325 */
1326 retval = 0;
1327 vma = next;
1328 break;
1329 }
1330 vma = next;
1331 }
1332
1333 /*
1334 * We need look no further than the maximum address a fragment
1335 * could possibly have landed at. Also cast things to loff_t to
1336 * prevent overflows and make comparisons vs. equal-width types.
1337 */
1338 size = PAGE_ALIGN(size);
1339 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1340 next = vma->vm_next;
1341
1342 /* finding a matching vma now does not alter retval */
1343 if ((vma->vm_ops == &shm_vm_ops) &&
1344 ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1345 (vma->vm_file == file))
1346 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1347 vma = next;
1348 }
1349
1350#else /* CONFIG_MMU */
1351 /* under NOMMU conditions, the exact address to be destroyed must be
1352 * given */
1353 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1354 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1355 retval = 0;
1356 }
1357
1358#endif
1359
1360 up_write(&mm->mmap_sem);
1361 return retval;
1362}
1363
1364#ifdef CONFIG_PROC_FS
1365static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1366{
1367 struct user_namespace *user_ns = seq_user_ns(s);
1368 struct shmid_kernel *shp = it;
1369 unsigned long rss = 0, swp = 0;
1370
1371 shm_add_rss_swap(shp, &rss, &swp);
1372
1373#if BITS_PER_LONG <= 32
1374#define SIZE_SPEC "%10lu"
1375#else
1376#define SIZE_SPEC "%21lu"
1377#endif
1378
1379 seq_printf(s,
1380 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1381 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1382 SIZE_SPEC " " SIZE_SPEC "\n",
1383 shp->shm_perm.key,
1384 shp->shm_perm.id,
1385 shp->shm_perm.mode,
1386 shp->shm_segsz,
1387 shp->shm_cprid,
1388 shp->shm_lprid,
1389 shp->shm_nattch,
1390 from_kuid_munged(user_ns, shp->shm_perm.uid),
1391 from_kgid_munged(user_ns, shp->shm_perm.gid),
1392 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1393 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1394 shp->shm_atim,
1395 shp->shm_dtim,
1396 shp->shm_ctim,
1397 rss * PAGE_SIZE,
1398 swp * PAGE_SIZE);
1399
1400 return 0;
1401}
1402#endif