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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/ipc/shm.c
4 * Copyright (C) 1992, 1993 Krishna Balasubramanian
5 * Many improvements/fixes by Bruno Haible.
6 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
7 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
8 *
9 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
10 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
11 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
12 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
13 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
14 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
15 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
16 *
17 * support for audit of ipc object properties and permission changes
18 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
19 *
20 * namespaces support
21 * OpenVZ, SWsoft Inc.
22 * Pavel Emelianov <xemul@openvz.org>
23 *
24 * Better ipc lock (kern_ipc_perm.lock) handling
25 * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
26 */
27
28#include <linux/slab.h>
29#include <linux/mm.h>
30#include <linux/hugetlb.h>
31#include <linux/shm.h>
32#include <linux/init.h>
33#include <linux/file.h>
34#include <linux/mman.h>
35#include <linux/shmem_fs.h>
36#include <linux/security.h>
37#include <linux/syscalls.h>
38#include <linux/audit.h>
39#include <linux/capability.h>
40#include <linux/ptrace.h>
41#include <linux/seq_file.h>
42#include <linux/rwsem.h>
43#include <linux/nsproxy.h>
44#include <linux/mount.h>
45#include <linux/ipc_namespace.h>
46#include <linux/rhashtable.h>
47
48#include <linux/uaccess.h>
49
50#include "util.h"
51
52struct shmid_kernel /* private to the kernel */
53{
54 struct kern_ipc_perm shm_perm;
55 struct file *shm_file;
56 unsigned long shm_nattch;
57 unsigned long shm_segsz;
58 time64_t shm_atim;
59 time64_t shm_dtim;
60 time64_t shm_ctim;
61 struct pid *shm_cprid;
62 struct pid *shm_lprid;
63 struct user_struct *mlock_user;
64
65 /* The task created the shm object. NULL if the task is dead. */
66 struct task_struct *shm_creator;
67 struct list_head shm_clist; /* list by creator */
68} __randomize_layout;
69
70/* shm_mode upper byte flags */
71#define SHM_DEST 01000 /* segment will be destroyed on last detach */
72#define SHM_LOCKED 02000 /* segment will not be swapped */
73
74struct shm_file_data {
75 int id;
76 struct ipc_namespace *ns;
77 struct file *file;
78 const struct vm_operations_struct *vm_ops;
79};
80
81#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
82
83static const struct file_operations shm_file_operations;
84static const struct vm_operations_struct shm_vm_ops;
85
86#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
87
88#define shm_unlock(shp) \
89 ipc_unlock(&(shp)->shm_perm)
90
91static int newseg(struct ipc_namespace *, struct ipc_params *);
92static void shm_open(struct vm_area_struct *vma);
93static void shm_close(struct vm_area_struct *vma);
94static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
95#ifdef CONFIG_PROC_FS
96static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
97#endif
98
99void shm_init_ns(struct ipc_namespace *ns)
100{
101 ns->shm_ctlmax = SHMMAX;
102 ns->shm_ctlall = SHMALL;
103 ns->shm_ctlmni = SHMMNI;
104 ns->shm_rmid_forced = 0;
105 ns->shm_tot = 0;
106 ipc_init_ids(&shm_ids(ns));
107}
108
109/*
110 * Called with shm_ids.rwsem (writer) and the shp structure locked.
111 * Only shm_ids.rwsem remains locked on exit.
112 */
113static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
114{
115 struct shmid_kernel *shp;
116
117 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
118
119 if (shp->shm_nattch) {
120 shp->shm_perm.mode |= SHM_DEST;
121 /* Do not find it any more */
122 ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
123 shm_unlock(shp);
124 } else
125 shm_destroy(ns, shp);
126}
127
128#ifdef CONFIG_IPC_NS
129void shm_exit_ns(struct ipc_namespace *ns)
130{
131 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
132 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
133 rhashtable_destroy(&ns->ids[IPC_SHM_IDS].key_ht);
134}
135#endif
136
137static int __init ipc_ns_init(void)
138{
139 shm_init_ns(&init_ipc_ns);
140 return 0;
141}
142
143pure_initcall(ipc_ns_init);
144
145void __init shm_init(void)
146{
147 ipc_init_proc_interface("sysvipc/shm",
148#if BITS_PER_LONG <= 32
149 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
150#else
151 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
152#endif
153 IPC_SHM_IDS, sysvipc_shm_proc_show);
154}
155
156static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
157{
158 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
159
160 if (IS_ERR(ipcp))
161 return ERR_CAST(ipcp);
162
163 return container_of(ipcp, struct shmid_kernel, shm_perm);
164}
165
166static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
167{
168 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
169
170 if (IS_ERR(ipcp))
171 return ERR_CAST(ipcp);
172
173 return container_of(ipcp, struct shmid_kernel, shm_perm);
174}
175
176/*
177 * shm_lock_(check_) routines are called in the paths where the rwsem
178 * is not necessarily held.
179 */
180static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
181{
182 struct kern_ipc_perm *ipcp;
183
184 rcu_read_lock();
185 ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
186 if (IS_ERR(ipcp))
187 goto err;
188
189 ipc_lock_object(ipcp);
190 /*
191 * ipc_rmid() may have already freed the ID while ipc_lock_object()
192 * was spinning: here verify that the structure is still valid.
193 * Upon races with RMID, return -EIDRM, thus indicating that
194 * the ID points to a removed identifier.
195 */
196 if (ipc_valid_object(ipcp)) {
197 /* return a locked ipc object upon success */
198 return container_of(ipcp, struct shmid_kernel, shm_perm);
199 }
200
201 ipc_unlock_object(ipcp);
202 ipcp = ERR_PTR(-EIDRM);
203err:
204 rcu_read_unlock();
205 /*
206 * Callers of shm_lock() must validate the status of the returned ipc
207 * object pointer and error out as appropriate.
208 */
209 return ERR_CAST(ipcp);
210}
211
212static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
213{
214 rcu_read_lock();
215 ipc_lock_object(&ipcp->shm_perm);
216}
217
218static void shm_rcu_free(struct rcu_head *head)
219{
220 struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
221 rcu);
222 struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
223 shm_perm);
224 security_shm_free(&shp->shm_perm);
225 kvfree(shp);
226}
227
228static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
229{
230 list_del(&s->shm_clist);
231 ipc_rmid(&shm_ids(ns), &s->shm_perm);
232}
233
234
235static int __shm_open(struct vm_area_struct *vma)
236{
237 struct file *file = vma->vm_file;
238 struct shm_file_data *sfd = shm_file_data(file);
239 struct shmid_kernel *shp;
240
241 shp = shm_lock(sfd->ns, sfd->id);
242
243 if (IS_ERR(shp))
244 return PTR_ERR(shp);
245
246 if (shp->shm_file != sfd->file) {
247 /* ID was reused */
248 shm_unlock(shp);
249 return -EINVAL;
250 }
251
252 shp->shm_atim = ktime_get_real_seconds();
253 ipc_update_pid(&shp->shm_lprid, task_tgid(current));
254 shp->shm_nattch++;
255 shm_unlock(shp);
256 return 0;
257}
258
259/* This is called by fork, once for every shm attach. */
260static void shm_open(struct vm_area_struct *vma)
261{
262 int err = __shm_open(vma);
263 /*
264 * We raced in the idr lookup or with shm_destroy().
265 * Either way, the ID is busted.
266 */
267 WARN_ON_ONCE(err);
268}
269
270/*
271 * shm_destroy - free the struct shmid_kernel
272 *
273 * @ns: namespace
274 * @shp: struct to free
275 *
276 * It has to be called with shp and shm_ids.rwsem (writer) locked,
277 * but returns with shp unlocked and freed.
278 */
279static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
280{
281 struct file *shm_file;
282
283 shm_file = shp->shm_file;
284 shp->shm_file = NULL;
285 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
286 shm_rmid(ns, shp);
287 shm_unlock(shp);
288 if (!is_file_hugepages(shm_file))
289 shmem_lock(shm_file, 0, shp->mlock_user);
290 else if (shp->mlock_user)
291 user_shm_unlock(i_size_read(file_inode(shm_file)),
292 shp->mlock_user);
293 fput(shm_file);
294 ipc_update_pid(&shp->shm_cprid, NULL);
295 ipc_update_pid(&shp->shm_lprid, NULL);
296 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
297}
298
299/*
300 * shm_may_destroy - identifies whether shm segment should be destroyed now
301 *
302 * Returns true if and only if there are no active users of the segment and
303 * one of the following is true:
304 *
305 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
306 *
307 * 2) sysctl kernel.shm_rmid_forced is set to 1.
308 */
309static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
310{
311 return (shp->shm_nattch == 0) &&
312 (ns->shm_rmid_forced ||
313 (shp->shm_perm.mode & SHM_DEST));
314}
315
316/*
317 * remove the attach descriptor vma.
318 * free memory for segment if it is marked destroyed.
319 * The descriptor has already been removed from the current->mm->mmap list
320 * and will later be kfree()d.
321 */
322static void shm_close(struct vm_area_struct *vma)
323{
324 struct file *file = vma->vm_file;
325 struct shm_file_data *sfd = shm_file_data(file);
326 struct shmid_kernel *shp;
327 struct ipc_namespace *ns = sfd->ns;
328
329 down_write(&shm_ids(ns).rwsem);
330 /* remove from the list of attaches of the shm segment */
331 shp = shm_lock(ns, sfd->id);
332
333 /*
334 * We raced in the idr lookup or with shm_destroy().
335 * Either way, the ID is busted.
336 */
337 if (WARN_ON_ONCE(IS_ERR(shp)))
338 goto done; /* no-op */
339
340 ipc_update_pid(&shp->shm_lprid, task_tgid(current));
341 shp->shm_dtim = ktime_get_real_seconds();
342 shp->shm_nattch--;
343 if (shm_may_destroy(ns, shp))
344 shm_destroy(ns, shp);
345 else
346 shm_unlock(shp);
347done:
348 up_write(&shm_ids(ns).rwsem);
349}
350
351/* Called with ns->shm_ids(ns).rwsem locked */
352static int shm_try_destroy_orphaned(int id, void *p, void *data)
353{
354 struct ipc_namespace *ns = data;
355 struct kern_ipc_perm *ipcp = p;
356 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
357
358 /*
359 * We want to destroy segments without users and with already
360 * exit'ed originating process.
361 *
362 * As shp->* are changed under rwsem, it's safe to skip shp locking.
363 */
364 if (shp->shm_creator != NULL)
365 return 0;
366
367 if (shm_may_destroy(ns, shp)) {
368 shm_lock_by_ptr(shp);
369 shm_destroy(ns, shp);
370 }
371 return 0;
372}
373
374void shm_destroy_orphaned(struct ipc_namespace *ns)
375{
376 down_write(&shm_ids(ns).rwsem);
377 if (shm_ids(ns).in_use)
378 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
379 up_write(&shm_ids(ns).rwsem);
380}
381
382/* Locking assumes this will only be called with task == current */
383void exit_shm(struct task_struct *task)
384{
385 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
386 struct shmid_kernel *shp, *n;
387
388 if (list_empty(&task->sysvshm.shm_clist))
389 return;
390
391 /*
392 * If kernel.shm_rmid_forced is not set then only keep track of
393 * which shmids are orphaned, so that a later set of the sysctl
394 * can clean them up.
395 */
396 if (!ns->shm_rmid_forced) {
397 down_read(&shm_ids(ns).rwsem);
398 list_for_each_entry(shp, &task->sysvshm.shm_clist, shm_clist)
399 shp->shm_creator = NULL;
400 /*
401 * Only under read lock but we are only called on current
402 * so no entry on the list will be shared.
403 */
404 list_del(&task->sysvshm.shm_clist);
405 up_read(&shm_ids(ns).rwsem);
406 return;
407 }
408
409 /*
410 * Destroy all already created segments, that were not yet mapped,
411 * and mark any mapped as orphan to cover the sysctl toggling.
412 * Destroy is skipped if shm_may_destroy() returns false.
413 */
414 down_write(&shm_ids(ns).rwsem);
415 list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) {
416 shp->shm_creator = NULL;
417
418 if (shm_may_destroy(ns, shp)) {
419 shm_lock_by_ptr(shp);
420 shm_destroy(ns, shp);
421 }
422 }
423
424 /* Remove the list head from any segments still attached. */
425 list_del(&task->sysvshm.shm_clist);
426 up_write(&shm_ids(ns).rwsem);
427}
428
429static vm_fault_t shm_fault(struct vm_fault *vmf)
430{
431 struct file *file = vmf->vma->vm_file;
432 struct shm_file_data *sfd = shm_file_data(file);
433
434 return sfd->vm_ops->fault(vmf);
435}
436
437static int shm_split(struct vm_area_struct *vma, unsigned long addr)
438{
439 struct file *file = vma->vm_file;
440 struct shm_file_data *sfd = shm_file_data(file);
441
442 if (sfd->vm_ops->split)
443 return sfd->vm_ops->split(vma, addr);
444
445 return 0;
446}
447
448static unsigned long shm_pagesize(struct vm_area_struct *vma)
449{
450 struct file *file = vma->vm_file;
451 struct shm_file_data *sfd = shm_file_data(file);
452
453 if (sfd->vm_ops->pagesize)
454 return sfd->vm_ops->pagesize(vma);
455
456 return PAGE_SIZE;
457}
458
459#ifdef CONFIG_NUMA
460static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
461{
462 struct file *file = vma->vm_file;
463 struct shm_file_data *sfd = shm_file_data(file);
464 int err = 0;
465
466 if (sfd->vm_ops->set_policy)
467 err = sfd->vm_ops->set_policy(vma, new);
468 return err;
469}
470
471static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
472 unsigned long addr)
473{
474 struct file *file = vma->vm_file;
475 struct shm_file_data *sfd = shm_file_data(file);
476 struct mempolicy *pol = NULL;
477
478 if (sfd->vm_ops->get_policy)
479 pol = sfd->vm_ops->get_policy(vma, addr);
480 else if (vma->vm_policy)
481 pol = vma->vm_policy;
482
483 return pol;
484}
485#endif
486
487static int shm_mmap(struct file *file, struct vm_area_struct *vma)
488{
489 struct shm_file_data *sfd = shm_file_data(file);
490 int ret;
491
492 /*
493 * In case of remap_file_pages() emulation, the file can represent an
494 * IPC ID that was removed, and possibly even reused by another shm
495 * segment already. Propagate this case as an error to caller.
496 */
497 ret = __shm_open(vma);
498 if (ret)
499 return ret;
500
501 ret = call_mmap(sfd->file, vma);
502 if (ret) {
503 shm_close(vma);
504 return ret;
505 }
506 sfd->vm_ops = vma->vm_ops;
507#ifdef CONFIG_MMU
508 WARN_ON(!sfd->vm_ops->fault);
509#endif
510 vma->vm_ops = &shm_vm_ops;
511 return 0;
512}
513
514static int shm_release(struct inode *ino, struct file *file)
515{
516 struct shm_file_data *sfd = shm_file_data(file);
517
518 put_ipc_ns(sfd->ns);
519 fput(sfd->file);
520 shm_file_data(file) = NULL;
521 kfree(sfd);
522 return 0;
523}
524
525static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
526{
527 struct shm_file_data *sfd = shm_file_data(file);
528
529 if (!sfd->file->f_op->fsync)
530 return -EINVAL;
531 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
532}
533
534static long shm_fallocate(struct file *file, int mode, loff_t offset,
535 loff_t len)
536{
537 struct shm_file_data *sfd = shm_file_data(file);
538
539 if (!sfd->file->f_op->fallocate)
540 return -EOPNOTSUPP;
541 return sfd->file->f_op->fallocate(file, mode, offset, len);
542}
543
544static unsigned long shm_get_unmapped_area(struct file *file,
545 unsigned long addr, unsigned long len, unsigned long pgoff,
546 unsigned long flags)
547{
548 struct shm_file_data *sfd = shm_file_data(file);
549
550 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
551 pgoff, flags);
552}
553
554static const struct file_operations shm_file_operations = {
555 .mmap = shm_mmap,
556 .fsync = shm_fsync,
557 .release = shm_release,
558 .get_unmapped_area = shm_get_unmapped_area,
559 .llseek = noop_llseek,
560 .fallocate = shm_fallocate,
561};
562
563/*
564 * shm_file_operations_huge is now identical to shm_file_operations,
565 * but we keep it distinct for the sake of is_file_shm_hugepages().
566 */
567static const struct file_operations shm_file_operations_huge = {
568 .mmap = shm_mmap,
569 .fsync = shm_fsync,
570 .release = shm_release,
571 .get_unmapped_area = shm_get_unmapped_area,
572 .llseek = noop_llseek,
573 .fallocate = shm_fallocate,
574};
575
576bool is_file_shm_hugepages(struct file *file)
577{
578 return file->f_op == &shm_file_operations_huge;
579}
580
581static const struct vm_operations_struct shm_vm_ops = {
582 .open = shm_open, /* callback for a new vm-area open */
583 .close = shm_close, /* callback for when the vm-area is released */
584 .fault = shm_fault,
585 .split = shm_split,
586 .pagesize = shm_pagesize,
587#if defined(CONFIG_NUMA)
588 .set_policy = shm_set_policy,
589 .get_policy = shm_get_policy,
590#endif
591};
592
593/**
594 * newseg - Create a new shared memory segment
595 * @ns: namespace
596 * @params: ptr to the structure that contains key, size and shmflg
597 *
598 * Called with shm_ids.rwsem held as a writer.
599 */
600static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
601{
602 key_t key = params->key;
603 int shmflg = params->flg;
604 size_t size = params->u.size;
605 int error;
606 struct shmid_kernel *shp;
607 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
608 struct file *file;
609 char name[13];
610 vm_flags_t acctflag = 0;
611
612 if (size < SHMMIN || size > ns->shm_ctlmax)
613 return -EINVAL;
614
615 if (numpages << PAGE_SHIFT < size)
616 return -ENOSPC;
617
618 if (ns->shm_tot + numpages < ns->shm_tot ||
619 ns->shm_tot + numpages > ns->shm_ctlall)
620 return -ENOSPC;
621
622 shp = kvmalloc(sizeof(*shp), GFP_KERNEL);
623 if (unlikely(!shp))
624 return -ENOMEM;
625
626 shp->shm_perm.key = key;
627 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
628 shp->mlock_user = NULL;
629
630 shp->shm_perm.security = NULL;
631 error = security_shm_alloc(&shp->shm_perm);
632 if (error) {
633 kvfree(shp);
634 return error;
635 }
636
637 sprintf(name, "SYSV%08x", key);
638 if (shmflg & SHM_HUGETLB) {
639 struct hstate *hs;
640 size_t hugesize;
641
642 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
643 if (!hs) {
644 error = -EINVAL;
645 goto no_file;
646 }
647 hugesize = ALIGN(size, huge_page_size(hs));
648
649 /* hugetlb_file_setup applies strict accounting */
650 if (shmflg & SHM_NORESERVE)
651 acctflag = VM_NORESERVE;
652 file = hugetlb_file_setup(name, hugesize, acctflag,
653 &shp->mlock_user, HUGETLB_SHMFS_INODE,
654 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
655 } else {
656 /*
657 * Do not allow no accounting for OVERCOMMIT_NEVER, even
658 * if it's asked for.
659 */
660 if ((shmflg & SHM_NORESERVE) &&
661 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
662 acctflag = VM_NORESERVE;
663 file = shmem_kernel_file_setup(name, size, acctflag);
664 }
665 error = PTR_ERR(file);
666 if (IS_ERR(file))
667 goto no_file;
668
669 shp->shm_cprid = get_pid(task_tgid(current));
670 shp->shm_lprid = NULL;
671 shp->shm_atim = shp->shm_dtim = 0;
672 shp->shm_ctim = ktime_get_real_seconds();
673 shp->shm_segsz = size;
674 shp->shm_nattch = 0;
675 shp->shm_file = file;
676 shp->shm_creator = current;
677
678 /* ipc_addid() locks shp upon success. */
679 error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
680 if (error < 0)
681 goto no_id;
682
683 list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist);
684
685 /*
686 * shmid gets reported as "inode#" in /proc/pid/maps.
687 * proc-ps tools use this. Changing this will break them.
688 */
689 file_inode(file)->i_ino = shp->shm_perm.id;
690
691 ns->shm_tot += numpages;
692 error = shp->shm_perm.id;
693
694 ipc_unlock_object(&shp->shm_perm);
695 rcu_read_unlock();
696 return error;
697
698no_id:
699 ipc_update_pid(&shp->shm_cprid, NULL);
700 ipc_update_pid(&shp->shm_lprid, NULL);
701 if (is_file_hugepages(file) && shp->mlock_user)
702 user_shm_unlock(size, shp->mlock_user);
703 fput(file);
704 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
705 return error;
706no_file:
707 call_rcu(&shp->shm_perm.rcu, shm_rcu_free);
708 return error;
709}
710
711/*
712 * Called with shm_ids.rwsem and ipcp locked.
713 */
714static int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
715{
716 struct shmid_kernel *shp;
717
718 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
719 if (shp->shm_segsz < params->u.size)
720 return -EINVAL;
721
722 return 0;
723}
724
725long ksys_shmget(key_t key, size_t size, int shmflg)
726{
727 struct ipc_namespace *ns;
728 static const struct ipc_ops shm_ops = {
729 .getnew = newseg,
730 .associate = security_shm_associate,
731 .more_checks = shm_more_checks,
732 };
733 struct ipc_params shm_params;
734
735 ns = current->nsproxy->ipc_ns;
736
737 shm_params.key = key;
738 shm_params.flg = shmflg;
739 shm_params.u.size = size;
740
741 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
742}
743
744SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
745{
746 return ksys_shmget(key, size, shmflg);
747}
748
749static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
750{
751 switch (version) {
752 case IPC_64:
753 return copy_to_user(buf, in, sizeof(*in));
754 case IPC_OLD:
755 {
756 struct shmid_ds out;
757
758 memset(&out, 0, sizeof(out));
759 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
760 out.shm_segsz = in->shm_segsz;
761 out.shm_atime = in->shm_atime;
762 out.shm_dtime = in->shm_dtime;
763 out.shm_ctime = in->shm_ctime;
764 out.shm_cpid = in->shm_cpid;
765 out.shm_lpid = in->shm_lpid;
766 out.shm_nattch = in->shm_nattch;
767
768 return copy_to_user(buf, &out, sizeof(out));
769 }
770 default:
771 return -EINVAL;
772 }
773}
774
775static inline unsigned long
776copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
777{
778 switch (version) {
779 case IPC_64:
780 if (copy_from_user(out, buf, sizeof(*out)))
781 return -EFAULT;
782 return 0;
783 case IPC_OLD:
784 {
785 struct shmid_ds tbuf_old;
786
787 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
788 return -EFAULT;
789
790 out->shm_perm.uid = tbuf_old.shm_perm.uid;
791 out->shm_perm.gid = tbuf_old.shm_perm.gid;
792 out->shm_perm.mode = tbuf_old.shm_perm.mode;
793
794 return 0;
795 }
796 default:
797 return -EINVAL;
798 }
799}
800
801static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
802{
803 switch (version) {
804 case IPC_64:
805 return copy_to_user(buf, in, sizeof(*in));
806 case IPC_OLD:
807 {
808 struct shminfo out;
809
810 if (in->shmmax > INT_MAX)
811 out.shmmax = INT_MAX;
812 else
813 out.shmmax = (int)in->shmmax;
814
815 out.shmmin = in->shmmin;
816 out.shmmni = in->shmmni;
817 out.shmseg = in->shmseg;
818 out.shmall = in->shmall;
819
820 return copy_to_user(buf, &out, sizeof(out));
821 }
822 default:
823 return -EINVAL;
824 }
825}
826
827/*
828 * Calculate and add used RSS and swap pages of a shm.
829 * Called with shm_ids.rwsem held as a reader
830 */
831static void shm_add_rss_swap(struct shmid_kernel *shp,
832 unsigned long *rss_add, unsigned long *swp_add)
833{
834 struct inode *inode;
835
836 inode = file_inode(shp->shm_file);
837
838 if (is_file_hugepages(shp->shm_file)) {
839 struct address_space *mapping = inode->i_mapping;
840 struct hstate *h = hstate_file(shp->shm_file);
841 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
842 } else {
843#ifdef CONFIG_SHMEM
844 struct shmem_inode_info *info = SHMEM_I(inode);
845
846 spin_lock_irq(&info->lock);
847 *rss_add += inode->i_mapping->nrpages;
848 *swp_add += info->swapped;
849 spin_unlock_irq(&info->lock);
850#else
851 *rss_add += inode->i_mapping->nrpages;
852#endif
853 }
854}
855
856/*
857 * Called with shm_ids.rwsem held as a reader
858 */
859static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
860 unsigned long *swp)
861{
862 int next_id;
863 int total, in_use;
864
865 *rss = 0;
866 *swp = 0;
867
868 in_use = shm_ids(ns).in_use;
869
870 for (total = 0, next_id = 0; total < in_use; next_id++) {
871 struct kern_ipc_perm *ipc;
872 struct shmid_kernel *shp;
873
874 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
875 if (ipc == NULL)
876 continue;
877 shp = container_of(ipc, struct shmid_kernel, shm_perm);
878
879 shm_add_rss_swap(shp, rss, swp);
880
881 total++;
882 }
883}
884
885/*
886 * This function handles some shmctl commands which require the rwsem
887 * to be held in write mode.
888 * NOTE: no locks must be held, the rwsem is taken inside this function.
889 */
890static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
891 struct shmid64_ds *shmid64)
892{
893 struct kern_ipc_perm *ipcp;
894 struct shmid_kernel *shp;
895 int err;
896
897 down_write(&shm_ids(ns).rwsem);
898 rcu_read_lock();
899
900 ipcp = ipcctl_obtain_check(ns, &shm_ids(ns), shmid, cmd,
901 &shmid64->shm_perm, 0);
902 if (IS_ERR(ipcp)) {
903 err = PTR_ERR(ipcp);
904 goto out_unlock1;
905 }
906
907 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
908
909 err = security_shm_shmctl(&shp->shm_perm, cmd);
910 if (err)
911 goto out_unlock1;
912
913 switch (cmd) {
914 case IPC_RMID:
915 ipc_lock_object(&shp->shm_perm);
916 /* do_shm_rmid unlocks the ipc object and rcu */
917 do_shm_rmid(ns, ipcp);
918 goto out_up;
919 case IPC_SET:
920 ipc_lock_object(&shp->shm_perm);
921 err = ipc_update_perm(&shmid64->shm_perm, ipcp);
922 if (err)
923 goto out_unlock0;
924 shp->shm_ctim = ktime_get_real_seconds();
925 break;
926 default:
927 err = -EINVAL;
928 goto out_unlock1;
929 }
930
931out_unlock0:
932 ipc_unlock_object(&shp->shm_perm);
933out_unlock1:
934 rcu_read_unlock();
935out_up:
936 up_write(&shm_ids(ns).rwsem);
937 return err;
938}
939
940static int shmctl_ipc_info(struct ipc_namespace *ns,
941 struct shminfo64 *shminfo)
942{
943 int err = security_shm_shmctl(NULL, IPC_INFO);
944 if (!err) {
945 memset(shminfo, 0, sizeof(*shminfo));
946 shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
947 shminfo->shmmax = ns->shm_ctlmax;
948 shminfo->shmall = ns->shm_ctlall;
949 shminfo->shmmin = SHMMIN;
950 down_read(&shm_ids(ns).rwsem);
951 err = ipc_get_maxidx(&shm_ids(ns));
952 up_read(&shm_ids(ns).rwsem);
953 if (err < 0)
954 err = 0;
955 }
956 return err;
957}
958
959static int shmctl_shm_info(struct ipc_namespace *ns,
960 struct shm_info *shm_info)
961{
962 int err = security_shm_shmctl(NULL, SHM_INFO);
963 if (!err) {
964 memset(shm_info, 0, sizeof(*shm_info));
965 down_read(&shm_ids(ns).rwsem);
966 shm_info->used_ids = shm_ids(ns).in_use;
967 shm_get_stat(ns, &shm_info->shm_rss, &shm_info->shm_swp);
968 shm_info->shm_tot = ns->shm_tot;
969 shm_info->swap_attempts = 0;
970 shm_info->swap_successes = 0;
971 err = ipc_get_maxidx(&shm_ids(ns));
972 up_read(&shm_ids(ns).rwsem);
973 if (err < 0)
974 err = 0;
975 }
976 return err;
977}
978
979static int shmctl_stat(struct ipc_namespace *ns, int shmid,
980 int cmd, struct shmid64_ds *tbuf)
981{
982 struct shmid_kernel *shp;
983 int err;
984
985 memset(tbuf, 0, sizeof(*tbuf));
986
987 rcu_read_lock();
988 if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
989 shp = shm_obtain_object(ns, shmid);
990 if (IS_ERR(shp)) {
991 err = PTR_ERR(shp);
992 goto out_unlock;
993 }
994 } else { /* IPC_STAT */
995 shp = shm_obtain_object_check(ns, shmid);
996 if (IS_ERR(shp)) {
997 err = PTR_ERR(shp);
998 goto out_unlock;
999 }
1000 }
1001
1002 /*
1003 * Semantically SHM_STAT_ANY ought to be identical to
1004 * that functionality provided by the /proc/sysvipc/
1005 * interface. As such, only audit these calls and
1006 * do not do traditional S_IRUGO permission checks on
1007 * the ipc object.
1008 */
1009 if (cmd == SHM_STAT_ANY)
1010 audit_ipc_obj(&shp->shm_perm);
1011 else {
1012 err = -EACCES;
1013 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
1014 goto out_unlock;
1015 }
1016
1017 err = security_shm_shmctl(&shp->shm_perm, cmd);
1018 if (err)
1019 goto out_unlock;
1020
1021 ipc_lock_object(&shp->shm_perm);
1022
1023 if (!ipc_valid_object(&shp->shm_perm)) {
1024 ipc_unlock_object(&shp->shm_perm);
1025 err = -EIDRM;
1026 goto out_unlock;
1027 }
1028
1029 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf->shm_perm);
1030 tbuf->shm_segsz = shp->shm_segsz;
1031 tbuf->shm_atime = shp->shm_atim;
1032 tbuf->shm_dtime = shp->shm_dtim;
1033 tbuf->shm_ctime = shp->shm_ctim;
1034#ifndef CONFIG_64BIT
1035 tbuf->shm_atime_high = shp->shm_atim >> 32;
1036 tbuf->shm_dtime_high = shp->shm_dtim >> 32;
1037 tbuf->shm_ctime_high = shp->shm_ctim >> 32;
1038#endif
1039 tbuf->shm_cpid = pid_vnr(shp->shm_cprid);
1040 tbuf->shm_lpid = pid_vnr(shp->shm_lprid);
1041 tbuf->shm_nattch = shp->shm_nattch;
1042
1043 if (cmd == IPC_STAT) {
1044 /*
1045 * As defined in SUS:
1046 * Return 0 on success
1047 */
1048 err = 0;
1049 } else {
1050 /*
1051 * SHM_STAT and SHM_STAT_ANY (both Linux specific)
1052 * Return the full id, including the sequence number
1053 */
1054 err = shp->shm_perm.id;
1055 }
1056
1057 ipc_unlock_object(&shp->shm_perm);
1058out_unlock:
1059 rcu_read_unlock();
1060 return err;
1061}
1062
1063static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
1064{
1065 struct shmid_kernel *shp;
1066 struct file *shm_file;
1067 int err;
1068
1069 rcu_read_lock();
1070 shp = shm_obtain_object_check(ns, shmid);
1071 if (IS_ERR(shp)) {
1072 err = PTR_ERR(shp);
1073 goto out_unlock1;
1074 }
1075
1076 audit_ipc_obj(&(shp->shm_perm));
1077 err = security_shm_shmctl(&shp->shm_perm, cmd);
1078 if (err)
1079 goto out_unlock1;
1080
1081 ipc_lock_object(&shp->shm_perm);
1082
1083 /* check if shm_destroy() is tearing down shp */
1084 if (!ipc_valid_object(&shp->shm_perm)) {
1085 err = -EIDRM;
1086 goto out_unlock0;
1087 }
1088
1089 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
1090 kuid_t euid = current_euid();
1091
1092 if (!uid_eq(euid, shp->shm_perm.uid) &&
1093 !uid_eq(euid, shp->shm_perm.cuid)) {
1094 err = -EPERM;
1095 goto out_unlock0;
1096 }
1097 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1098 err = -EPERM;
1099 goto out_unlock0;
1100 }
1101 }
1102
1103 shm_file = shp->shm_file;
1104 if (is_file_hugepages(shm_file))
1105 goto out_unlock0;
1106
1107 if (cmd == SHM_LOCK) {
1108 struct user_struct *user = current_user();
1109
1110 err = shmem_lock(shm_file, 1, user);
1111 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1112 shp->shm_perm.mode |= SHM_LOCKED;
1113 shp->mlock_user = user;
1114 }
1115 goto out_unlock0;
1116 }
1117
1118 /* SHM_UNLOCK */
1119 if (!(shp->shm_perm.mode & SHM_LOCKED))
1120 goto out_unlock0;
1121 shmem_lock(shm_file, 0, shp->mlock_user);
1122 shp->shm_perm.mode &= ~SHM_LOCKED;
1123 shp->mlock_user = NULL;
1124 get_file(shm_file);
1125 ipc_unlock_object(&shp->shm_perm);
1126 rcu_read_unlock();
1127 shmem_unlock_mapping(shm_file->f_mapping);
1128
1129 fput(shm_file);
1130 return err;
1131
1132out_unlock0:
1133 ipc_unlock_object(&shp->shm_perm);
1134out_unlock1:
1135 rcu_read_unlock();
1136 return err;
1137}
1138
1139static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
1140{
1141 int err;
1142 struct ipc_namespace *ns;
1143 struct shmid64_ds sem64;
1144
1145 if (cmd < 0 || shmid < 0)
1146 return -EINVAL;
1147
1148 ns = current->nsproxy->ipc_ns;
1149
1150 switch (cmd) {
1151 case IPC_INFO: {
1152 struct shminfo64 shminfo;
1153 err = shmctl_ipc_info(ns, &shminfo);
1154 if (err < 0)
1155 return err;
1156 if (copy_shminfo_to_user(buf, &shminfo, version))
1157 err = -EFAULT;
1158 return err;
1159 }
1160 case SHM_INFO: {
1161 struct shm_info shm_info;
1162 err = shmctl_shm_info(ns, &shm_info);
1163 if (err < 0)
1164 return err;
1165 if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
1166 err = -EFAULT;
1167 return err;
1168 }
1169 case SHM_STAT:
1170 case SHM_STAT_ANY:
1171 case IPC_STAT: {
1172 err = shmctl_stat(ns, shmid, cmd, &sem64);
1173 if (err < 0)
1174 return err;
1175 if (copy_shmid_to_user(buf, &sem64, version))
1176 err = -EFAULT;
1177 return err;
1178 }
1179 case IPC_SET:
1180 if (copy_shmid_from_user(&sem64, buf, version))
1181 return -EFAULT;
1182 fallthrough;
1183 case IPC_RMID:
1184 return shmctl_down(ns, shmid, cmd, &sem64);
1185 case SHM_LOCK:
1186 case SHM_UNLOCK:
1187 return shmctl_do_lock(ns, shmid, cmd);
1188 default:
1189 return -EINVAL;
1190 }
1191}
1192
1193SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1194{
1195 return ksys_shmctl(shmid, cmd, buf, IPC_64);
1196}
1197
1198#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1199long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
1200{
1201 int version = ipc_parse_version(&cmd);
1202
1203 return ksys_shmctl(shmid, cmd, buf, version);
1204}
1205
1206SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1207{
1208 return ksys_old_shmctl(shmid, cmd, buf);
1209}
1210#endif
1211
1212#ifdef CONFIG_COMPAT
1213
1214struct compat_shmid_ds {
1215 struct compat_ipc_perm shm_perm;
1216 int shm_segsz;
1217 old_time32_t shm_atime;
1218 old_time32_t shm_dtime;
1219 old_time32_t shm_ctime;
1220 compat_ipc_pid_t shm_cpid;
1221 compat_ipc_pid_t shm_lpid;
1222 unsigned short shm_nattch;
1223 unsigned short shm_unused;
1224 compat_uptr_t shm_unused2;
1225 compat_uptr_t shm_unused3;
1226};
1227
1228struct compat_shminfo64 {
1229 compat_ulong_t shmmax;
1230 compat_ulong_t shmmin;
1231 compat_ulong_t shmmni;
1232 compat_ulong_t shmseg;
1233 compat_ulong_t shmall;
1234 compat_ulong_t __unused1;
1235 compat_ulong_t __unused2;
1236 compat_ulong_t __unused3;
1237 compat_ulong_t __unused4;
1238};
1239
1240struct compat_shm_info {
1241 compat_int_t used_ids;
1242 compat_ulong_t shm_tot, shm_rss, shm_swp;
1243 compat_ulong_t swap_attempts, swap_successes;
1244};
1245
1246static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
1247 int version)
1248{
1249 if (in->shmmax > INT_MAX)
1250 in->shmmax = INT_MAX;
1251 if (version == IPC_64) {
1252 struct compat_shminfo64 info;
1253 memset(&info, 0, sizeof(info));
1254 info.shmmax = in->shmmax;
1255 info.shmmin = in->shmmin;
1256 info.shmmni = in->shmmni;
1257 info.shmseg = in->shmseg;
1258 info.shmall = in->shmall;
1259 return copy_to_user(buf, &info, sizeof(info));
1260 } else {
1261 struct shminfo info;
1262 memset(&info, 0, sizeof(info));
1263 info.shmmax = in->shmmax;
1264 info.shmmin = in->shmmin;
1265 info.shmmni = in->shmmni;
1266 info.shmseg = in->shmseg;
1267 info.shmall = in->shmall;
1268 return copy_to_user(buf, &info, sizeof(info));
1269 }
1270}
1271
1272static int put_compat_shm_info(struct shm_info *ip,
1273 struct compat_shm_info __user *uip)
1274{
1275 struct compat_shm_info info;
1276
1277 memset(&info, 0, sizeof(info));
1278 info.used_ids = ip->used_ids;
1279 info.shm_tot = ip->shm_tot;
1280 info.shm_rss = ip->shm_rss;
1281 info.shm_swp = ip->shm_swp;
1282 info.swap_attempts = ip->swap_attempts;
1283 info.swap_successes = ip->swap_successes;
1284 return copy_to_user(uip, &info, sizeof(info));
1285}
1286
1287static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
1288 int version)
1289{
1290 if (version == IPC_64) {
1291 struct compat_shmid64_ds v;
1292 memset(&v, 0, sizeof(v));
1293 to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
1294 v.shm_atime = lower_32_bits(in->shm_atime);
1295 v.shm_atime_high = upper_32_bits(in->shm_atime);
1296 v.shm_dtime = lower_32_bits(in->shm_dtime);
1297 v.shm_dtime_high = upper_32_bits(in->shm_dtime);
1298 v.shm_ctime = lower_32_bits(in->shm_ctime);
1299 v.shm_ctime_high = upper_32_bits(in->shm_ctime);
1300 v.shm_segsz = in->shm_segsz;
1301 v.shm_nattch = in->shm_nattch;
1302 v.shm_cpid = in->shm_cpid;
1303 v.shm_lpid = in->shm_lpid;
1304 return copy_to_user(buf, &v, sizeof(v));
1305 } else {
1306 struct compat_shmid_ds v;
1307 memset(&v, 0, sizeof(v));
1308 to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
1309 v.shm_perm.key = in->shm_perm.key;
1310 v.shm_atime = in->shm_atime;
1311 v.shm_dtime = in->shm_dtime;
1312 v.shm_ctime = in->shm_ctime;
1313 v.shm_segsz = in->shm_segsz;
1314 v.shm_nattch = in->shm_nattch;
1315 v.shm_cpid = in->shm_cpid;
1316 v.shm_lpid = in->shm_lpid;
1317 return copy_to_user(buf, &v, sizeof(v));
1318 }
1319}
1320
1321static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
1322 int version)
1323{
1324 memset(out, 0, sizeof(*out));
1325 if (version == IPC_64) {
1326 struct compat_shmid64_ds __user *p = buf;
1327 return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
1328 } else {
1329 struct compat_shmid_ds __user *p = buf;
1330 return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
1331 }
1332}
1333
1334static long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
1335{
1336 struct ipc_namespace *ns;
1337 struct shmid64_ds sem64;
1338 int err;
1339
1340 ns = current->nsproxy->ipc_ns;
1341
1342 if (cmd < 0 || shmid < 0)
1343 return -EINVAL;
1344
1345 switch (cmd) {
1346 case IPC_INFO: {
1347 struct shminfo64 shminfo;
1348 err = shmctl_ipc_info(ns, &shminfo);
1349 if (err < 0)
1350 return err;
1351 if (copy_compat_shminfo_to_user(uptr, &shminfo, version))
1352 err = -EFAULT;
1353 return err;
1354 }
1355 case SHM_INFO: {
1356 struct shm_info shm_info;
1357 err = shmctl_shm_info(ns, &shm_info);
1358 if (err < 0)
1359 return err;
1360 if (put_compat_shm_info(&shm_info, uptr))
1361 err = -EFAULT;
1362 return err;
1363 }
1364 case IPC_STAT:
1365 case SHM_STAT_ANY:
1366 case SHM_STAT:
1367 err = shmctl_stat(ns, shmid, cmd, &sem64);
1368 if (err < 0)
1369 return err;
1370 if (copy_compat_shmid_to_user(uptr, &sem64, version))
1371 err = -EFAULT;
1372 return err;
1373
1374 case IPC_SET:
1375 if (copy_compat_shmid_from_user(&sem64, uptr, version))
1376 return -EFAULT;
1377 fallthrough;
1378 case IPC_RMID:
1379 return shmctl_down(ns, shmid, cmd, &sem64);
1380 case SHM_LOCK:
1381 case SHM_UNLOCK:
1382 return shmctl_do_lock(ns, shmid, cmd);
1383 default:
1384 return -EINVAL;
1385 }
1386 return err;
1387}
1388
1389COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
1390{
1391 return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
1392}
1393
1394#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1395long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
1396{
1397 int version = compat_ipc_parse_version(&cmd);
1398
1399 return compat_ksys_shmctl(shmid, cmd, uptr, version);
1400}
1401
1402COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
1403{
1404 return compat_ksys_old_shmctl(shmid, cmd, uptr);
1405}
1406#endif
1407#endif
1408
1409/*
1410 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1411 *
1412 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1413 * "raddr" thing points to kernel space, and there has to be a wrapper around
1414 * this.
1415 */
1416long do_shmat(int shmid, char __user *shmaddr, int shmflg,
1417 ulong *raddr, unsigned long shmlba)
1418{
1419 struct shmid_kernel *shp;
1420 unsigned long addr = (unsigned long)shmaddr;
1421 unsigned long size;
1422 struct file *file, *base;
1423 int err;
1424 unsigned long flags = MAP_SHARED;
1425 unsigned long prot;
1426 int acc_mode;
1427 struct ipc_namespace *ns;
1428 struct shm_file_data *sfd;
1429 int f_flags;
1430 unsigned long populate = 0;
1431
1432 err = -EINVAL;
1433 if (shmid < 0)
1434 goto out;
1435
1436 if (addr) {
1437 if (addr & (shmlba - 1)) {
1438 if (shmflg & SHM_RND) {
1439 addr &= ~(shmlba - 1); /* round down */
1440
1441 /*
1442 * Ensure that the round-down is non-nil
1443 * when remapping. This can happen for
1444 * cases when addr < shmlba.
1445 */
1446 if (!addr && (shmflg & SHM_REMAP))
1447 goto out;
1448 } else
1449#ifndef __ARCH_FORCE_SHMLBA
1450 if (addr & ~PAGE_MASK)
1451#endif
1452 goto out;
1453 }
1454
1455 flags |= MAP_FIXED;
1456 } else if ((shmflg & SHM_REMAP))
1457 goto out;
1458
1459 if (shmflg & SHM_RDONLY) {
1460 prot = PROT_READ;
1461 acc_mode = S_IRUGO;
1462 f_flags = O_RDONLY;
1463 } else {
1464 prot = PROT_READ | PROT_WRITE;
1465 acc_mode = S_IRUGO | S_IWUGO;
1466 f_flags = O_RDWR;
1467 }
1468 if (shmflg & SHM_EXEC) {
1469 prot |= PROT_EXEC;
1470 acc_mode |= S_IXUGO;
1471 }
1472
1473 /*
1474 * We cannot rely on the fs check since SYSV IPC does have an
1475 * additional creator id...
1476 */
1477 ns = current->nsproxy->ipc_ns;
1478 rcu_read_lock();
1479 shp = shm_obtain_object_check(ns, shmid);
1480 if (IS_ERR(shp)) {
1481 err = PTR_ERR(shp);
1482 goto out_unlock;
1483 }
1484
1485 err = -EACCES;
1486 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1487 goto out_unlock;
1488
1489 err = security_shm_shmat(&shp->shm_perm, shmaddr, shmflg);
1490 if (err)
1491 goto out_unlock;
1492
1493 ipc_lock_object(&shp->shm_perm);
1494
1495 /* check if shm_destroy() is tearing down shp */
1496 if (!ipc_valid_object(&shp->shm_perm)) {
1497 ipc_unlock_object(&shp->shm_perm);
1498 err = -EIDRM;
1499 goto out_unlock;
1500 }
1501
1502 /*
1503 * We need to take a reference to the real shm file to prevent the
1504 * pointer from becoming stale in cases where the lifetime of the outer
1505 * file extends beyond that of the shm segment. It's not usually
1506 * possible, but it can happen during remap_file_pages() emulation as
1507 * that unmaps the memory, then does ->mmap() via file reference only.
1508 * We'll deny the ->mmap() if the shm segment was since removed, but to
1509 * detect shm ID reuse we need to compare the file pointers.
1510 */
1511 base = get_file(shp->shm_file);
1512 shp->shm_nattch++;
1513 size = i_size_read(file_inode(base));
1514 ipc_unlock_object(&shp->shm_perm);
1515 rcu_read_unlock();
1516
1517 err = -ENOMEM;
1518 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1519 if (!sfd) {
1520 fput(base);
1521 goto out_nattch;
1522 }
1523
1524 file = alloc_file_clone(base, f_flags,
1525 is_file_hugepages(base) ?
1526 &shm_file_operations_huge :
1527 &shm_file_operations);
1528 err = PTR_ERR(file);
1529 if (IS_ERR(file)) {
1530 kfree(sfd);
1531 fput(base);
1532 goto out_nattch;
1533 }
1534
1535 sfd->id = shp->shm_perm.id;
1536 sfd->ns = get_ipc_ns(ns);
1537 sfd->file = base;
1538 sfd->vm_ops = NULL;
1539 file->private_data = sfd;
1540
1541 err = security_mmap_file(file, prot, flags);
1542 if (err)
1543 goto out_fput;
1544
1545 if (mmap_write_lock_killable(current->mm)) {
1546 err = -EINTR;
1547 goto out_fput;
1548 }
1549
1550 if (addr && !(shmflg & SHM_REMAP)) {
1551 err = -EINVAL;
1552 if (addr + size < addr)
1553 goto invalid;
1554
1555 if (find_vma_intersection(current->mm, addr, addr + size))
1556 goto invalid;
1557 }
1558
1559 addr = do_mmap(file, addr, size, prot, flags, 0, &populate, NULL);
1560 *raddr = addr;
1561 err = 0;
1562 if (IS_ERR_VALUE(addr))
1563 err = (long)addr;
1564invalid:
1565 mmap_write_unlock(current->mm);
1566 if (populate)
1567 mm_populate(addr, populate);
1568
1569out_fput:
1570 fput(file);
1571
1572out_nattch:
1573 down_write(&shm_ids(ns).rwsem);
1574 shp = shm_lock(ns, shmid);
1575 shp->shm_nattch--;
1576 if (shm_may_destroy(ns, shp))
1577 shm_destroy(ns, shp);
1578 else
1579 shm_unlock(shp);
1580 up_write(&shm_ids(ns).rwsem);
1581 return err;
1582
1583out_unlock:
1584 rcu_read_unlock();
1585out:
1586 return err;
1587}
1588
1589SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1590{
1591 unsigned long ret;
1592 long err;
1593
1594 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1595 if (err)
1596 return err;
1597 force_successful_syscall_return();
1598 return (long)ret;
1599}
1600
1601#ifdef CONFIG_COMPAT
1602
1603#ifndef COMPAT_SHMLBA
1604#define COMPAT_SHMLBA SHMLBA
1605#endif
1606
1607COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
1608{
1609 unsigned long ret;
1610 long err;
1611
1612 err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
1613 if (err)
1614 return err;
1615 force_successful_syscall_return();
1616 return (long)ret;
1617}
1618#endif
1619
1620/*
1621 * detach and kill segment if marked destroyed.
1622 * The work is done in shm_close.
1623 */
1624long ksys_shmdt(char __user *shmaddr)
1625{
1626 struct mm_struct *mm = current->mm;
1627 struct vm_area_struct *vma;
1628 unsigned long addr = (unsigned long)shmaddr;
1629 int retval = -EINVAL;
1630#ifdef CONFIG_MMU
1631 loff_t size = 0;
1632 struct file *file;
1633 struct vm_area_struct *next;
1634#endif
1635
1636 if (addr & ~PAGE_MASK)
1637 return retval;
1638
1639 if (mmap_write_lock_killable(mm))
1640 return -EINTR;
1641
1642 /*
1643 * This function tries to be smart and unmap shm segments that
1644 * were modified by partial mlock or munmap calls:
1645 * - It first determines the size of the shm segment that should be
1646 * unmapped: It searches for a vma that is backed by shm and that
1647 * started at address shmaddr. It records it's size and then unmaps
1648 * it.
1649 * - Then it unmaps all shm vmas that started at shmaddr and that
1650 * are within the initially determined size and that are from the
1651 * same shm segment from which we determined the size.
1652 * Errors from do_munmap are ignored: the function only fails if
1653 * it's called with invalid parameters or if it's called to unmap
1654 * a part of a vma. Both calls in this function are for full vmas,
1655 * the parameters are directly copied from the vma itself and always
1656 * valid - therefore do_munmap cannot fail. (famous last words?)
1657 */
1658 /*
1659 * If it had been mremap()'d, the starting address would not
1660 * match the usual checks anyway. So assume all vma's are
1661 * above the starting address given.
1662 */
1663 vma = find_vma(mm, addr);
1664
1665#ifdef CONFIG_MMU
1666 while (vma) {
1667 next = vma->vm_next;
1668
1669 /*
1670 * Check if the starting address would match, i.e. it's
1671 * a fragment created by mprotect() and/or munmap(), or it
1672 * otherwise it starts at this address with no hassles.
1673 */
1674 if ((vma->vm_ops == &shm_vm_ops) &&
1675 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1676
1677 /*
1678 * Record the file of the shm segment being
1679 * unmapped. With mremap(), someone could place
1680 * page from another segment but with equal offsets
1681 * in the range we are unmapping.
1682 */
1683 file = vma->vm_file;
1684 size = i_size_read(file_inode(vma->vm_file));
1685 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1686 /*
1687 * We discovered the size of the shm segment, so
1688 * break out of here and fall through to the next
1689 * loop that uses the size information to stop
1690 * searching for matching vma's.
1691 */
1692 retval = 0;
1693 vma = next;
1694 break;
1695 }
1696 vma = next;
1697 }
1698
1699 /*
1700 * We need look no further than the maximum address a fragment
1701 * could possibly have landed at. Also cast things to loff_t to
1702 * prevent overflows and make comparisons vs. equal-width types.
1703 */
1704 size = PAGE_ALIGN(size);
1705 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1706 next = vma->vm_next;
1707
1708 /* finding a matching vma now does not alter retval */
1709 if ((vma->vm_ops == &shm_vm_ops) &&
1710 ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1711 (vma->vm_file == file))
1712 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1713 vma = next;
1714 }
1715
1716#else /* CONFIG_MMU */
1717 /* under NOMMU conditions, the exact address to be destroyed must be
1718 * given
1719 */
1720 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1721 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1722 retval = 0;
1723 }
1724
1725#endif
1726
1727 mmap_write_unlock(mm);
1728 return retval;
1729}
1730
1731SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1732{
1733 return ksys_shmdt(shmaddr);
1734}
1735
1736#ifdef CONFIG_PROC_FS
1737static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1738{
1739 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1740 struct user_namespace *user_ns = seq_user_ns(s);
1741 struct kern_ipc_perm *ipcp = it;
1742 struct shmid_kernel *shp;
1743 unsigned long rss = 0, swp = 0;
1744
1745 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
1746 shm_add_rss_swap(shp, &rss, &swp);
1747
1748#if BITS_PER_LONG <= 32
1749#define SIZE_SPEC "%10lu"
1750#else
1751#define SIZE_SPEC "%21lu"
1752#endif
1753
1754 seq_printf(s,
1755 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1756 "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
1757 SIZE_SPEC " " SIZE_SPEC "\n",
1758 shp->shm_perm.key,
1759 shp->shm_perm.id,
1760 shp->shm_perm.mode,
1761 shp->shm_segsz,
1762 pid_nr_ns(shp->shm_cprid, pid_ns),
1763 pid_nr_ns(shp->shm_lprid, pid_ns),
1764 shp->shm_nattch,
1765 from_kuid_munged(user_ns, shp->shm_perm.uid),
1766 from_kgid_munged(user_ns, shp->shm_perm.gid),
1767 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1768 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1769 shp->shm_atim,
1770 shp->shm_dtim,
1771 shp->shm_ctim,
1772 rss * PAGE_SIZE,
1773 swp * PAGE_SIZE);
1774
1775 return 0;
1776}
1777#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 <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