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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// 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 <uapi/linux/shm.h>
33#include <linux/init.h>
34#include <linux/file.h>
35#include <linux/mman.h>
36#include <linux/shmem_fs.h>
37#include <linux/security.h>
38#include <linux/syscalls.h>
39#include <linux/audit.h>
40#include <linux/capability.h>
41#include <linux/ptrace.h>
42#include <linux/seq_file.h>
43#include <linux/rwsem.h>
44#include <linux/nsproxy.h>
45#include <linux/mount.h>
46#include <linux/ipc_namespace.h>
47#include <linux/rhashtable.h>
48
49#include <linux/uaccess.h>
50
51#include "util.h"
52
53struct shmid_kernel /* private to the kernel */
54{
55 struct kern_ipc_perm shm_perm;
56 struct file *shm_file;
57 unsigned long shm_nattch;
58 unsigned long shm_segsz;
59 time64_t shm_atim;
60 time64_t shm_dtim;
61 time64_t shm_ctim;
62 struct pid *shm_cprid;
63 struct pid *shm_lprid;
64 struct ucounts *mlock_ucounts;
65
66 /*
67 * The task created the shm object, for
68 * task_lock(shp->shm_creator)
69 */
70 struct task_struct *shm_creator;
71
72 /*
73 * List by creator. task_lock(->shm_creator) required for read/write.
74 * If list_empty(), then the creator is dead already.
75 */
76 struct list_head shm_clist;
77 struct ipc_namespace *ns;
78} __randomize_layout;
79
80/* shm_mode upper byte flags */
81#define SHM_DEST 01000 /* segment will be destroyed on last detach */
82#define SHM_LOCKED 02000 /* segment will not be swapped */
83
84struct shm_file_data {
85 int id;
86 struct ipc_namespace *ns;
87 struct file *file;
88 const struct vm_operations_struct *vm_ops;
89};
90
91#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
92
93static const struct file_operations shm_file_operations;
94static const struct vm_operations_struct shm_vm_ops;
95
96#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
97
98#define shm_unlock(shp) \
99 ipc_unlock(&(shp)->shm_perm)
100
101static int newseg(struct ipc_namespace *, struct ipc_params *);
102static void shm_open(struct vm_area_struct *vma);
103static void shm_close(struct vm_area_struct *vma);
104static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
105#ifdef CONFIG_PROC_FS
106static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
107#endif
108
109void shm_init_ns(struct ipc_namespace *ns)
110{
111 ns->shm_ctlmax = SHMMAX;
112 ns->shm_ctlall = SHMALL;
113 ns->shm_ctlmni = SHMMNI;
114 ns->shm_rmid_forced = 0;
115 ns->shm_tot = 0;
116 ipc_init_ids(&shm_ids(ns));
117}
118
119/*
120 * Called with shm_ids.rwsem (writer) and the shp structure locked.
121 * Only shm_ids.rwsem remains locked on exit.
122 */
123static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
124{
125 struct shmid_kernel *shp;
126
127 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
128 WARN_ON(ns != shp->ns);
129
130 if (shp->shm_nattch) {
131 shp->shm_perm.mode |= SHM_DEST;
132 /* Do not find it any more */
133 ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
134 shm_unlock(shp);
135 } else
136 shm_destroy(ns, shp);
137}
138
139#ifdef CONFIG_IPC_NS
140void shm_exit_ns(struct ipc_namespace *ns)
141{
142 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
143 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
144 rhashtable_destroy(&ns->ids[IPC_SHM_IDS].key_ht);
145}
146#endif
147
148static int __init ipc_ns_init(void)
149{
150 shm_init_ns(&init_ipc_ns);
151 return 0;
152}
153
154pure_initcall(ipc_ns_init);
155
156void __init shm_init(void)
157{
158 ipc_init_proc_interface("sysvipc/shm",
159#if BITS_PER_LONG <= 32
160 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
161#else
162 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
163#endif
164 IPC_SHM_IDS, sysvipc_shm_proc_show);
165}
166
167static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
168{
169 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
170
171 if (IS_ERR(ipcp))
172 return ERR_CAST(ipcp);
173
174 return container_of(ipcp, struct shmid_kernel, shm_perm);
175}
176
177static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
178{
179 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
180
181 if (IS_ERR(ipcp))
182 return ERR_CAST(ipcp);
183
184 return container_of(ipcp, struct shmid_kernel, shm_perm);
185}
186
187/*
188 * shm_lock_(check_) routines are called in the paths where the rwsem
189 * is not necessarily held.
190 */
191static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
192{
193 struct kern_ipc_perm *ipcp;
194
195 rcu_read_lock();
196 ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
197 if (IS_ERR(ipcp))
198 goto err;
199
200 ipc_lock_object(ipcp);
201 /*
202 * ipc_rmid() may have already freed the ID while ipc_lock_object()
203 * was spinning: here verify that the structure is still valid.
204 * Upon races with RMID, return -EIDRM, thus indicating that
205 * the ID points to a removed identifier.
206 */
207 if (ipc_valid_object(ipcp)) {
208 /* return a locked ipc object upon success */
209 return container_of(ipcp, struct shmid_kernel, shm_perm);
210 }
211
212 ipc_unlock_object(ipcp);
213 ipcp = ERR_PTR(-EIDRM);
214err:
215 rcu_read_unlock();
216 /*
217 * Callers of shm_lock() must validate the status of the returned ipc
218 * object pointer and error out as appropriate.
219 */
220 return ERR_CAST(ipcp);
221}
222
223static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
224{
225 rcu_read_lock();
226 ipc_lock_object(&ipcp->shm_perm);
227}
228
229static void shm_rcu_free(struct rcu_head *head)
230{
231 struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
232 rcu);
233 struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
234 shm_perm);
235 security_shm_free(&shp->shm_perm);
236 kfree(shp);
237}
238
239/*
240 * It has to be called with shp locked.
241 * It must be called before ipc_rmid()
242 */
243static inline void shm_clist_rm(struct shmid_kernel *shp)
244{
245 struct task_struct *creator;
246
247 /* ensure that shm_creator does not disappear */
248 rcu_read_lock();
249
250 /*
251 * A concurrent exit_shm may do a list_del_init() as well.
252 * Just do nothing if exit_shm already did the work
253 */
254 if (!list_empty(&shp->shm_clist)) {
255 /*
256 * shp->shm_creator is guaranteed to be valid *only*
257 * if shp->shm_clist is not empty.
258 */
259 creator = shp->shm_creator;
260
261 task_lock(creator);
262 /*
263 * list_del_init() is a nop if the entry was already removed
264 * from the list.
265 */
266 list_del_init(&shp->shm_clist);
267 task_unlock(creator);
268 }
269 rcu_read_unlock();
270}
271
272static inline void shm_rmid(struct shmid_kernel *s)
273{
274 shm_clist_rm(s);
275 ipc_rmid(&shm_ids(s->ns), &s->shm_perm);
276}
277
278
279static int __shm_open(struct shm_file_data *sfd)
280{
281 struct shmid_kernel *shp;
282
283 shp = shm_lock(sfd->ns, sfd->id);
284
285 if (IS_ERR(shp))
286 return PTR_ERR(shp);
287
288 if (shp->shm_file != sfd->file) {
289 /* ID was reused */
290 shm_unlock(shp);
291 return -EINVAL;
292 }
293
294 shp->shm_atim = ktime_get_real_seconds();
295 ipc_update_pid(&shp->shm_lprid, task_tgid(current));
296 shp->shm_nattch++;
297 shm_unlock(shp);
298 return 0;
299}
300
301/* This is called by fork, once for every shm attach. */
302static void shm_open(struct vm_area_struct *vma)
303{
304 struct file *file = vma->vm_file;
305 struct shm_file_data *sfd = shm_file_data(file);
306 int err;
307
308 /* Always call underlying open if present */
309 if (sfd->vm_ops->open)
310 sfd->vm_ops->open(vma);
311
312 err = __shm_open(sfd);
313 /*
314 * We raced in the idr lookup or with shm_destroy().
315 * Either way, the ID is busted.
316 */
317 WARN_ON_ONCE(err);
318}
319
320/*
321 * shm_destroy - free the struct shmid_kernel
322 *
323 * @ns: namespace
324 * @shp: struct to free
325 *
326 * It has to be called with shp and shm_ids.rwsem (writer) locked,
327 * but returns with shp unlocked and freed.
328 */
329static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
330{
331 struct file *shm_file;
332
333 shm_file = shp->shm_file;
334 shp->shm_file = NULL;
335 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
336 shm_rmid(shp);
337 shm_unlock(shp);
338 if (!is_file_hugepages(shm_file))
339 shmem_lock(shm_file, 0, shp->mlock_ucounts);
340 fput(shm_file);
341 ipc_update_pid(&shp->shm_cprid, NULL);
342 ipc_update_pid(&shp->shm_lprid, NULL);
343 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
344}
345
346/*
347 * shm_may_destroy - identifies whether shm segment should be destroyed now
348 *
349 * Returns true if and only if there are no active users of the segment and
350 * one of the following is true:
351 *
352 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
353 *
354 * 2) sysctl kernel.shm_rmid_forced is set to 1.
355 */
356static bool shm_may_destroy(struct shmid_kernel *shp)
357{
358 return (shp->shm_nattch == 0) &&
359 (shp->ns->shm_rmid_forced ||
360 (shp->shm_perm.mode & SHM_DEST));
361}
362
363/*
364 * remove the attach descriptor vma.
365 * free memory for segment if it is marked destroyed.
366 * The descriptor has already been removed from the current->mm->mmap list
367 * and will later be kfree()d.
368 */
369static void __shm_close(struct shm_file_data *sfd)
370{
371 struct shmid_kernel *shp;
372 struct ipc_namespace *ns = sfd->ns;
373
374 down_write(&shm_ids(ns).rwsem);
375 /* remove from the list of attaches of the shm segment */
376 shp = shm_lock(ns, sfd->id);
377
378 /*
379 * We raced in the idr lookup or with shm_destroy().
380 * Either way, the ID is busted.
381 */
382 if (WARN_ON_ONCE(IS_ERR(shp)))
383 goto done; /* no-op */
384
385 ipc_update_pid(&shp->shm_lprid, task_tgid(current));
386 shp->shm_dtim = ktime_get_real_seconds();
387 shp->shm_nattch--;
388 if (shm_may_destroy(shp))
389 shm_destroy(ns, shp);
390 else
391 shm_unlock(shp);
392done:
393 up_write(&shm_ids(ns).rwsem);
394}
395
396static void shm_close(struct vm_area_struct *vma)
397{
398 struct file *file = vma->vm_file;
399 struct shm_file_data *sfd = shm_file_data(file);
400
401 /* Always call underlying close if present */
402 if (sfd->vm_ops->close)
403 sfd->vm_ops->close(vma);
404
405 __shm_close(sfd);
406}
407
408/* Called with ns->shm_ids(ns).rwsem locked */
409static int shm_try_destroy_orphaned(int id, void *p, void *data)
410{
411 struct ipc_namespace *ns = data;
412 struct kern_ipc_perm *ipcp = p;
413 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
414
415 /*
416 * We want to destroy segments without users and with already
417 * exit'ed originating process.
418 *
419 * As shp->* are changed under rwsem, it's safe to skip shp locking.
420 */
421 if (!list_empty(&shp->shm_clist))
422 return 0;
423
424 if (shm_may_destroy(shp)) {
425 shm_lock_by_ptr(shp);
426 shm_destroy(ns, shp);
427 }
428 return 0;
429}
430
431void shm_destroy_orphaned(struct ipc_namespace *ns)
432{
433 down_write(&shm_ids(ns).rwsem);
434 if (shm_ids(ns).in_use)
435 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
436 up_write(&shm_ids(ns).rwsem);
437}
438
439/* Locking assumes this will only be called with task == current */
440void exit_shm(struct task_struct *task)
441{
442 for (;;) {
443 struct shmid_kernel *shp;
444 struct ipc_namespace *ns;
445
446 task_lock(task);
447
448 if (list_empty(&task->sysvshm.shm_clist)) {
449 task_unlock(task);
450 break;
451 }
452
453 shp = list_first_entry(&task->sysvshm.shm_clist, struct shmid_kernel,
454 shm_clist);
455
456 /*
457 * 1) Get pointer to the ipc namespace. It is worth to say
458 * that this pointer is guaranteed to be valid because
459 * shp lifetime is always shorter than namespace lifetime
460 * in which shp lives.
461 * We taken task_lock it means that shp won't be freed.
462 */
463 ns = shp->ns;
464
465 /*
466 * 2) If kernel.shm_rmid_forced is not set then only keep track of
467 * which shmids are orphaned, so that a later set of the sysctl
468 * can clean them up.
469 */
470 if (!ns->shm_rmid_forced)
471 goto unlink_continue;
472
473 /*
474 * 3) get a reference to the namespace.
475 * The refcount could be already 0. If it is 0, then
476 * the shm objects will be free by free_ipc_work().
477 */
478 ns = get_ipc_ns_not_zero(ns);
479 if (!ns) {
480unlink_continue:
481 list_del_init(&shp->shm_clist);
482 task_unlock(task);
483 continue;
484 }
485
486 /*
487 * 4) get a reference to shp.
488 * This cannot fail: shm_clist_rm() is called before
489 * ipc_rmid(), thus the refcount cannot be 0.
490 */
491 WARN_ON(!ipc_rcu_getref(&shp->shm_perm));
492
493 /*
494 * 5) unlink the shm segment from the list of segments
495 * created by current.
496 * This must be done last. After unlinking,
497 * only the refcounts obtained above prevent IPC_RMID
498 * from destroying the segment or the namespace.
499 */
500 list_del_init(&shp->shm_clist);
501
502 task_unlock(task);
503
504 /*
505 * 6) we have all references
506 * Thus lock & if needed destroy shp.
507 */
508 down_write(&shm_ids(ns).rwsem);
509 shm_lock_by_ptr(shp);
510 /*
511 * rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
512 * safe to call ipc_rcu_putref here
513 */
514 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
515
516 if (ipc_valid_object(&shp->shm_perm)) {
517 if (shm_may_destroy(shp))
518 shm_destroy(ns, shp);
519 else
520 shm_unlock(shp);
521 } else {
522 /*
523 * Someone else deleted the shp from namespace
524 * idr/kht while we have waited.
525 * Just unlock and continue.
526 */
527 shm_unlock(shp);
528 }
529
530 up_write(&shm_ids(ns).rwsem);
531 put_ipc_ns(ns); /* paired with get_ipc_ns_not_zero */
532 }
533}
534
535static vm_fault_t shm_fault(struct vm_fault *vmf)
536{
537 struct file *file = vmf->vma->vm_file;
538 struct shm_file_data *sfd = shm_file_data(file);
539
540 return sfd->vm_ops->fault(vmf);
541}
542
543static int shm_may_split(struct vm_area_struct *vma, unsigned long addr)
544{
545 struct file *file = vma->vm_file;
546 struct shm_file_data *sfd = shm_file_data(file);
547
548 if (sfd->vm_ops->may_split)
549 return sfd->vm_ops->may_split(vma, addr);
550
551 return 0;
552}
553
554static unsigned long shm_pagesize(struct vm_area_struct *vma)
555{
556 struct file *file = vma->vm_file;
557 struct shm_file_data *sfd = shm_file_data(file);
558
559 if (sfd->vm_ops->pagesize)
560 return sfd->vm_ops->pagesize(vma);
561
562 return PAGE_SIZE;
563}
564
565#ifdef CONFIG_NUMA
566static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
567{
568 struct shm_file_data *sfd = shm_file_data(vma->vm_file);
569 int err = 0;
570
571 if (sfd->vm_ops->set_policy)
572 err = sfd->vm_ops->set_policy(vma, mpol);
573 return err;
574}
575
576static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
577 unsigned long addr, pgoff_t *ilx)
578{
579 struct shm_file_data *sfd = shm_file_data(vma->vm_file);
580 struct mempolicy *mpol = vma->vm_policy;
581
582 if (sfd->vm_ops->get_policy)
583 mpol = sfd->vm_ops->get_policy(vma, addr, ilx);
584 return mpol;
585}
586#endif
587
588static int shm_mmap(struct file *file, struct vm_area_struct *vma)
589{
590 struct shm_file_data *sfd = shm_file_data(file);
591 int ret;
592
593 /*
594 * In case of remap_file_pages() emulation, the file can represent an
595 * IPC ID that was removed, and possibly even reused by another shm
596 * segment already. Propagate this case as an error to caller.
597 */
598 ret = __shm_open(sfd);
599 if (ret)
600 return ret;
601
602 ret = call_mmap(sfd->file, vma);
603 if (ret) {
604 __shm_close(sfd);
605 return ret;
606 }
607 sfd->vm_ops = vma->vm_ops;
608#ifdef CONFIG_MMU
609 WARN_ON(!sfd->vm_ops->fault);
610#endif
611 vma->vm_ops = &shm_vm_ops;
612 return 0;
613}
614
615static int shm_release(struct inode *ino, struct file *file)
616{
617 struct shm_file_data *sfd = shm_file_data(file);
618
619 put_ipc_ns(sfd->ns);
620 fput(sfd->file);
621 shm_file_data(file) = NULL;
622 kfree(sfd);
623 return 0;
624}
625
626static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
627{
628 struct shm_file_data *sfd = shm_file_data(file);
629
630 if (!sfd->file->f_op->fsync)
631 return -EINVAL;
632 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
633}
634
635static long shm_fallocate(struct file *file, int mode, loff_t offset,
636 loff_t len)
637{
638 struct shm_file_data *sfd = shm_file_data(file);
639
640 if (!sfd->file->f_op->fallocate)
641 return -EOPNOTSUPP;
642 return sfd->file->f_op->fallocate(file, mode, offset, len);
643}
644
645static unsigned long shm_get_unmapped_area(struct file *file,
646 unsigned long addr, unsigned long len, unsigned long pgoff,
647 unsigned long flags)
648{
649 struct shm_file_data *sfd = shm_file_data(file);
650
651 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
652 pgoff, flags);
653}
654
655static const struct file_operations shm_file_operations = {
656 .mmap = shm_mmap,
657 .fsync = shm_fsync,
658 .release = shm_release,
659 .get_unmapped_area = shm_get_unmapped_area,
660 .llseek = noop_llseek,
661 .fallocate = shm_fallocate,
662};
663
664/*
665 * shm_file_operations_huge is now identical to shm_file_operations,
666 * but we keep it distinct for the sake of is_file_shm_hugepages().
667 */
668static const struct file_operations shm_file_operations_huge = {
669 .mmap = shm_mmap,
670 .fsync = shm_fsync,
671 .release = shm_release,
672 .get_unmapped_area = shm_get_unmapped_area,
673 .llseek = noop_llseek,
674 .fallocate = shm_fallocate,
675};
676
677bool is_file_shm_hugepages(struct file *file)
678{
679 return file->f_op == &shm_file_operations_huge;
680}
681
682static const struct vm_operations_struct shm_vm_ops = {
683 .open = shm_open, /* callback for a new vm-area open */
684 .close = shm_close, /* callback for when the vm-area is released */
685 .fault = shm_fault,
686 .may_split = shm_may_split,
687 .pagesize = shm_pagesize,
688#if defined(CONFIG_NUMA)
689 .set_policy = shm_set_policy,
690 .get_policy = shm_get_policy,
691#endif
692};
693
694/**
695 * newseg - Create a new shared memory segment
696 * @ns: namespace
697 * @params: ptr to the structure that contains key, size and shmflg
698 *
699 * Called with shm_ids.rwsem held as a writer.
700 */
701static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
702{
703 key_t key = params->key;
704 int shmflg = params->flg;
705 size_t size = params->u.size;
706 int error;
707 struct shmid_kernel *shp;
708 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
709 struct file *file;
710 char name[13];
711 vm_flags_t acctflag = 0;
712
713 if (size < SHMMIN || size > ns->shm_ctlmax)
714 return -EINVAL;
715
716 if (numpages << PAGE_SHIFT < size)
717 return -ENOSPC;
718
719 if (ns->shm_tot + numpages < ns->shm_tot ||
720 ns->shm_tot + numpages > ns->shm_ctlall)
721 return -ENOSPC;
722
723 shp = kmalloc(sizeof(*shp), GFP_KERNEL_ACCOUNT);
724 if (unlikely(!shp))
725 return -ENOMEM;
726
727 shp->shm_perm.key = key;
728 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
729 shp->mlock_ucounts = NULL;
730
731 shp->shm_perm.security = NULL;
732 error = security_shm_alloc(&shp->shm_perm);
733 if (error) {
734 kfree(shp);
735 return error;
736 }
737
738 sprintf(name, "SYSV%08x", key);
739 if (shmflg & SHM_HUGETLB) {
740 struct hstate *hs;
741 size_t hugesize;
742
743 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
744 if (!hs) {
745 error = -EINVAL;
746 goto no_file;
747 }
748 hugesize = ALIGN(size, huge_page_size(hs));
749
750 /* hugetlb_file_setup applies strict accounting */
751 if (shmflg & SHM_NORESERVE)
752 acctflag = VM_NORESERVE;
753 file = hugetlb_file_setup(name, hugesize, acctflag,
754 HUGETLB_SHMFS_INODE, (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
755 } else {
756 /*
757 * Do not allow no accounting for OVERCOMMIT_NEVER, even
758 * if it's asked for.
759 */
760 if ((shmflg & SHM_NORESERVE) &&
761 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
762 acctflag = VM_NORESERVE;
763 file = shmem_kernel_file_setup(name, size, acctflag);
764 }
765 error = PTR_ERR(file);
766 if (IS_ERR(file))
767 goto no_file;
768
769 shp->shm_cprid = get_pid(task_tgid(current));
770 shp->shm_lprid = NULL;
771 shp->shm_atim = shp->shm_dtim = 0;
772 shp->shm_ctim = ktime_get_real_seconds();
773 shp->shm_segsz = size;
774 shp->shm_nattch = 0;
775 shp->shm_file = file;
776 shp->shm_creator = current;
777
778 /* ipc_addid() locks shp upon success. */
779 error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
780 if (error < 0)
781 goto no_id;
782
783 shp->ns = ns;
784
785 task_lock(current);
786 list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist);
787 task_unlock(current);
788
789 /*
790 * shmid gets reported as "inode#" in /proc/pid/maps.
791 * proc-ps tools use this. Changing this will break them.
792 */
793 file_inode(file)->i_ino = shp->shm_perm.id;
794
795 ns->shm_tot += numpages;
796 error = shp->shm_perm.id;
797
798 ipc_unlock_object(&shp->shm_perm);
799 rcu_read_unlock();
800 return error;
801
802no_id:
803 ipc_update_pid(&shp->shm_cprid, NULL);
804 ipc_update_pid(&shp->shm_lprid, NULL);
805 fput(file);
806 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
807 return error;
808no_file:
809 call_rcu(&shp->shm_perm.rcu, shm_rcu_free);
810 return error;
811}
812
813/*
814 * Called with shm_ids.rwsem and ipcp locked.
815 */
816static int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
817{
818 struct shmid_kernel *shp;
819
820 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
821 if (shp->shm_segsz < params->u.size)
822 return -EINVAL;
823
824 return 0;
825}
826
827long ksys_shmget(key_t key, size_t size, int shmflg)
828{
829 struct ipc_namespace *ns;
830 static const struct ipc_ops shm_ops = {
831 .getnew = newseg,
832 .associate = security_shm_associate,
833 .more_checks = shm_more_checks,
834 };
835 struct ipc_params shm_params;
836
837 ns = current->nsproxy->ipc_ns;
838
839 shm_params.key = key;
840 shm_params.flg = shmflg;
841 shm_params.u.size = size;
842
843 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
844}
845
846SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
847{
848 return ksys_shmget(key, size, shmflg);
849}
850
851static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
852{
853 switch (version) {
854 case IPC_64:
855 return copy_to_user(buf, in, sizeof(*in));
856 case IPC_OLD:
857 {
858 struct shmid_ds out;
859
860 memset(&out, 0, sizeof(out));
861 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
862 out.shm_segsz = in->shm_segsz;
863 out.shm_atime = in->shm_atime;
864 out.shm_dtime = in->shm_dtime;
865 out.shm_ctime = in->shm_ctime;
866 out.shm_cpid = in->shm_cpid;
867 out.shm_lpid = in->shm_lpid;
868 out.shm_nattch = in->shm_nattch;
869
870 return copy_to_user(buf, &out, sizeof(out));
871 }
872 default:
873 return -EINVAL;
874 }
875}
876
877static inline unsigned long
878copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
879{
880 switch (version) {
881 case IPC_64:
882 if (copy_from_user(out, buf, sizeof(*out)))
883 return -EFAULT;
884 return 0;
885 case IPC_OLD:
886 {
887 struct shmid_ds tbuf_old;
888
889 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
890 return -EFAULT;
891
892 out->shm_perm.uid = tbuf_old.shm_perm.uid;
893 out->shm_perm.gid = tbuf_old.shm_perm.gid;
894 out->shm_perm.mode = tbuf_old.shm_perm.mode;
895
896 return 0;
897 }
898 default:
899 return -EINVAL;
900 }
901}
902
903static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
904{
905 switch (version) {
906 case IPC_64:
907 return copy_to_user(buf, in, sizeof(*in));
908 case IPC_OLD:
909 {
910 struct shminfo out;
911
912 if (in->shmmax > INT_MAX)
913 out.shmmax = INT_MAX;
914 else
915 out.shmmax = (int)in->shmmax;
916
917 out.shmmin = in->shmmin;
918 out.shmmni = in->shmmni;
919 out.shmseg = in->shmseg;
920 out.shmall = in->shmall;
921
922 return copy_to_user(buf, &out, sizeof(out));
923 }
924 default:
925 return -EINVAL;
926 }
927}
928
929/*
930 * Calculate and add used RSS and swap pages of a shm.
931 * Called with shm_ids.rwsem held as a reader
932 */
933static void shm_add_rss_swap(struct shmid_kernel *shp,
934 unsigned long *rss_add, unsigned long *swp_add)
935{
936 struct inode *inode;
937
938 inode = file_inode(shp->shm_file);
939
940 if (is_file_hugepages(shp->shm_file)) {
941 struct address_space *mapping = inode->i_mapping;
942 struct hstate *h = hstate_file(shp->shm_file);
943 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
944 } else {
945#ifdef CONFIG_SHMEM
946 struct shmem_inode_info *info = SHMEM_I(inode);
947
948 spin_lock_irq(&info->lock);
949 *rss_add += inode->i_mapping->nrpages;
950 *swp_add += info->swapped;
951 spin_unlock_irq(&info->lock);
952#else
953 *rss_add += inode->i_mapping->nrpages;
954#endif
955 }
956}
957
958/*
959 * Called with shm_ids.rwsem held as a reader
960 */
961static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
962 unsigned long *swp)
963{
964 int next_id;
965 int total, in_use;
966
967 *rss = 0;
968 *swp = 0;
969
970 in_use = shm_ids(ns).in_use;
971
972 for (total = 0, next_id = 0; total < in_use; next_id++) {
973 struct kern_ipc_perm *ipc;
974 struct shmid_kernel *shp;
975
976 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
977 if (ipc == NULL)
978 continue;
979 shp = container_of(ipc, struct shmid_kernel, shm_perm);
980
981 shm_add_rss_swap(shp, rss, swp);
982
983 total++;
984 }
985}
986
987/*
988 * This function handles some shmctl commands which require the rwsem
989 * to be held in write mode.
990 * NOTE: no locks must be held, the rwsem is taken inside this function.
991 */
992static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
993 struct shmid64_ds *shmid64)
994{
995 struct kern_ipc_perm *ipcp;
996 struct shmid_kernel *shp;
997 int err;
998
999 down_write(&shm_ids(ns).rwsem);
1000 rcu_read_lock();
1001
1002 ipcp = ipcctl_obtain_check(ns, &shm_ids(ns), shmid, cmd,
1003 &shmid64->shm_perm, 0);
1004 if (IS_ERR(ipcp)) {
1005 err = PTR_ERR(ipcp);
1006 goto out_unlock1;
1007 }
1008
1009 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
1010
1011 err = security_shm_shmctl(&shp->shm_perm, cmd);
1012 if (err)
1013 goto out_unlock1;
1014
1015 switch (cmd) {
1016 case IPC_RMID:
1017 ipc_lock_object(&shp->shm_perm);
1018 /* do_shm_rmid unlocks the ipc object and rcu */
1019 do_shm_rmid(ns, ipcp);
1020 goto out_up;
1021 case IPC_SET:
1022 ipc_lock_object(&shp->shm_perm);
1023 err = ipc_update_perm(&shmid64->shm_perm, ipcp);
1024 if (err)
1025 goto out_unlock0;
1026 shp->shm_ctim = ktime_get_real_seconds();
1027 break;
1028 default:
1029 err = -EINVAL;
1030 goto out_unlock1;
1031 }
1032
1033out_unlock0:
1034 ipc_unlock_object(&shp->shm_perm);
1035out_unlock1:
1036 rcu_read_unlock();
1037out_up:
1038 up_write(&shm_ids(ns).rwsem);
1039 return err;
1040}
1041
1042static int shmctl_ipc_info(struct ipc_namespace *ns,
1043 struct shminfo64 *shminfo)
1044{
1045 int err = security_shm_shmctl(NULL, IPC_INFO);
1046 if (!err) {
1047 memset(shminfo, 0, sizeof(*shminfo));
1048 shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
1049 shminfo->shmmax = ns->shm_ctlmax;
1050 shminfo->shmall = ns->shm_ctlall;
1051 shminfo->shmmin = SHMMIN;
1052 down_read(&shm_ids(ns).rwsem);
1053 err = ipc_get_maxidx(&shm_ids(ns));
1054 up_read(&shm_ids(ns).rwsem);
1055 if (err < 0)
1056 err = 0;
1057 }
1058 return err;
1059}
1060
1061static int shmctl_shm_info(struct ipc_namespace *ns,
1062 struct shm_info *shm_info)
1063{
1064 int err = security_shm_shmctl(NULL, SHM_INFO);
1065 if (!err) {
1066 memset(shm_info, 0, sizeof(*shm_info));
1067 down_read(&shm_ids(ns).rwsem);
1068 shm_info->used_ids = shm_ids(ns).in_use;
1069 shm_get_stat(ns, &shm_info->shm_rss, &shm_info->shm_swp);
1070 shm_info->shm_tot = ns->shm_tot;
1071 shm_info->swap_attempts = 0;
1072 shm_info->swap_successes = 0;
1073 err = ipc_get_maxidx(&shm_ids(ns));
1074 up_read(&shm_ids(ns).rwsem);
1075 if (err < 0)
1076 err = 0;
1077 }
1078 return err;
1079}
1080
1081static int shmctl_stat(struct ipc_namespace *ns, int shmid,
1082 int cmd, struct shmid64_ds *tbuf)
1083{
1084 struct shmid_kernel *shp;
1085 int err;
1086
1087 memset(tbuf, 0, sizeof(*tbuf));
1088
1089 rcu_read_lock();
1090 if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
1091 shp = shm_obtain_object(ns, shmid);
1092 if (IS_ERR(shp)) {
1093 err = PTR_ERR(shp);
1094 goto out_unlock;
1095 }
1096 } else { /* IPC_STAT */
1097 shp = shm_obtain_object_check(ns, shmid);
1098 if (IS_ERR(shp)) {
1099 err = PTR_ERR(shp);
1100 goto out_unlock;
1101 }
1102 }
1103
1104 /*
1105 * Semantically SHM_STAT_ANY ought to be identical to
1106 * that functionality provided by the /proc/sysvipc/
1107 * interface. As such, only audit these calls and
1108 * do not do traditional S_IRUGO permission checks on
1109 * the ipc object.
1110 */
1111 if (cmd == SHM_STAT_ANY)
1112 audit_ipc_obj(&shp->shm_perm);
1113 else {
1114 err = -EACCES;
1115 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
1116 goto out_unlock;
1117 }
1118
1119 err = security_shm_shmctl(&shp->shm_perm, cmd);
1120 if (err)
1121 goto out_unlock;
1122
1123 ipc_lock_object(&shp->shm_perm);
1124
1125 if (!ipc_valid_object(&shp->shm_perm)) {
1126 ipc_unlock_object(&shp->shm_perm);
1127 err = -EIDRM;
1128 goto out_unlock;
1129 }
1130
1131 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf->shm_perm);
1132 tbuf->shm_segsz = shp->shm_segsz;
1133 tbuf->shm_atime = shp->shm_atim;
1134 tbuf->shm_dtime = shp->shm_dtim;
1135 tbuf->shm_ctime = shp->shm_ctim;
1136#ifndef CONFIG_64BIT
1137 tbuf->shm_atime_high = shp->shm_atim >> 32;
1138 tbuf->shm_dtime_high = shp->shm_dtim >> 32;
1139 tbuf->shm_ctime_high = shp->shm_ctim >> 32;
1140#endif
1141 tbuf->shm_cpid = pid_vnr(shp->shm_cprid);
1142 tbuf->shm_lpid = pid_vnr(shp->shm_lprid);
1143 tbuf->shm_nattch = shp->shm_nattch;
1144
1145 if (cmd == IPC_STAT) {
1146 /*
1147 * As defined in SUS:
1148 * Return 0 on success
1149 */
1150 err = 0;
1151 } else {
1152 /*
1153 * SHM_STAT and SHM_STAT_ANY (both Linux specific)
1154 * Return the full id, including the sequence number
1155 */
1156 err = shp->shm_perm.id;
1157 }
1158
1159 ipc_unlock_object(&shp->shm_perm);
1160out_unlock:
1161 rcu_read_unlock();
1162 return err;
1163}
1164
1165static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
1166{
1167 struct shmid_kernel *shp;
1168 struct file *shm_file;
1169 int err;
1170
1171 rcu_read_lock();
1172 shp = shm_obtain_object_check(ns, shmid);
1173 if (IS_ERR(shp)) {
1174 err = PTR_ERR(shp);
1175 goto out_unlock1;
1176 }
1177
1178 audit_ipc_obj(&(shp->shm_perm));
1179 err = security_shm_shmctl(&shp->shm_perm, cmd);
1180 if (err)
1181 goto out_unlock1;
1182
1183 ipc_lock_object(&shp->shm_perm);
1184
1185 /* check if shm_destroy() is tearing down shp */
1186 if (!ipc_valid_object(&shp->shm_perm)) {
1187 err = -EIDRM;
1188 goto out_unlock0;
1189 }
1190
1191 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
1192 kuid_t euid = current_euid();
1193
1194 if (!uid_eq(euid, shp->shm_perm.uid) &&
1195 !uid_eq(euid, shp->shm_perm.cuid)) {
1196 err = -EPERM;
1197 goto out_unlock0;
1198 }
1199 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1200 err = -EPERM;
1201 goto out_unlock0;
1202 }
1203 }
1204
1205 shm_file = shp->shm_file;
1206 if (is_file_hugepages(shm_file))
1207 goto out_unlock0;
1208
1209 if (cmd == SHM_LOCK) {
1210 struct ucounts *ucounts = current_ucounts();
1211
1212 err = shmem_lock(shm_file, 1, ucounts);
1213 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1214 shp->shm_perm.mode |= SHM_LOCKED;
1215 shp->mlock_ucounts = ucounts;
1216 }
1217 goto out_unlock0;
1218 }
1219
1220 /* SHM_UNLOCK */
1221 if (!(shp->shm_perm.mode & SHM_LOCKED))
1222 goto out_unlock0;
1223 shmem_lock(shm_file, 0, shp->mlock_ucounts);
1224 shp->shm_perm.mode &= ~SHM_LOCKED;
1225 shp->mlock_ucounts = NULL;
1226 get_file(shm_file);
1227 ipc_unlock_object(&shp->shm_perm);
1228 rcu_read_unlock();
1229 shmem_unlock_mapping(shm_file->f_mapping);
1230
1231 fput(shm_file);
1232 return err;
1233
1234out_unlock0:
1235 ipc_unlock_object(&shp->shm_perm);
1236out_unlock1:
1237 rcu_read_unlock();
1238 return err;
1239}
1240
1241static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
1242{
1243 int err;
1244 struct ipc_namespace *ns;
1245 struct shmid64_ds sem64;
1246
1247 if (cmd < 0 || shmid < 0)
1248 return -EINVAL;
1249
1250 ns = current->nsproxy->ipc_ns;
1251
1252 switch (cmd) {
1253 case IPC_INFO: {
1254 struct shminfo64 shminfo;
1255 err = shmctl_ipc_info(ns, &shminfo);
1256 if (err < 0)
1257 return err;
1258 if (copy_shminfo_to_user(buf, &shminfo, version))
1259 err = -EFAULT;
1260 return err;
1261 }
1262 case SHM_INFO: {
1263 struct shm_info shm_info;
1264 err = shmctl_shm_info(ns, &shm_info);
1265 if (err < 0)
1266 return err;
1267 if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
1268 err = -EFAULT;
1269 return err;
1270 }
1271 case SHM_STAT:
1272 case SHM_STAT_ANY:
1273 case IPC_STAT: {
1274 err = shmctl_stat(ns, shmid, cmd, &sem64);
1275 if (err < 0)
1276 return err;
1277 if (copy_shmid_to_user(buf, &sem64, version))
1278 err = -EFAULT;
1279 return err;
1280 }
1281 case IPC_SET:
1282 if (copy_shmid_from_user(&sem64, buf, version))
1283 return -EFAULT;
1284 fallthrough;
1285 case IPC_RMID:
1286 return shmctl_down(ns, shmid, cmd, &sem64);
1287 case SHM_LOCK:
1288 case SHM_UNLOCK:
1289 return shmctl_do_lock(ns, shmid, cmd);
1290 default:
1291 return -EINVAL;
1292 }
1293}
1294
1295SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1296{
1297 return ksys_shmctl(shmid, cmd, buf, IPC_64);
1298}
1299
1300#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1301long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
1302{
1303 int version = ipc_parse_version(&cmd);
1304
1305 return ksys_shmctl(shmid, cmd, buf, version);
1306}
1307
1308SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1309{
1310 return ksys_old_shmctl(shmid, cmd, buf);
1311}
1312#endif
1313
1314#ifdef CONFIG_COMPAT
1315
1316struct compat_shmid_ds {
1317 struct compat_ipc_perm shm_perm;
1318 int shm_segsz;
1319 old_time32_t shm_atime;
1320 old_time32_t shm_dtime;
1321 old_time32_t shm_ctime;
1322 compat_ipc_pid_t shm_cpid;
1323 compat_ipc_pid_t shm_lpid;
1324 unsigned short shm_nattch;
1325 unsigned short shm_unused;
1326 compat_uptr_t shm_unused2;
1327 compat_uptr_t shm_unused3;
1328};
1329
1330struct compat_shminfo64 {
1331 compat_ulong_t shmmax;
1332 compat_ulong_t shmmin;
1333 compat_ulong_t shmmni;
1334 compat_ulong_t shmseg;
1335 compat_ulong_t shmall;
1336 compat_ulong_t __unused1;
1337 compat_ulong_t __unused2;
1338 compat_ulong_t __unused3;
1339 compat_ulong_t __unused4;
1340};
1341
1342struct compat_shm_info {
1343 compat_int_t used_ids;
1344 compat_ulong_t shm_tot, shm_rss, shm_swp;
1345 compat_ulong_t swap_attempts, swap_successes;
1346};
1347
1348static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
1349 int version)
1350{
1351 if (in->shmmax > INT_MAX)
1352 in->shmmax = INT_MAX;
1353 if (version == IPC_64) {
1354 struct compat_shminfo64 info;
1355 memset(&info, 0, sizeof(info));
1356 info.shmmax = in->shmmax;
1357 info.shmmin = in->shmmin;
1358 info.shmmni = in->shmmni;
1359 info.shmseg = in->shmseg;
1360 info.shmall = in->shmall;
1361 return copy_to_user(buf, &info, sizeof(info));
1362 } else {
1363 struct shminfo info;
1364 memset(&info, 0, sizeof(info));
1365 info.shmmax = in->shmmax;
1366 info.shmmin = in->shmmin;
1367 info.shmmni = in->shmmni;
1368 info.shmseg = in->shmseg;
1369 info.shmall = in->shmall;
1370 return copy_to_user(buf, &info, sizeof(info));
1371 }
1372}
1373
1374static int put_compat_shm_info(struct shm_info *ip,
1375 struct compat_shm_info __user *uip)
1376{
1377 struct compat_shm_info info;
1378
1379 memset(&info, 0, sizeof(info));
1380 info.used_ids = ip->used_ids;
1381 info.shm_tot = ip->shm_tot;
1382 info.shm_rss = ip->shm_rss;
1383 info.shm_swp = ip->shm_swp;
1384 info.swap_attempts = ip->swap_attempts;
1385 info.swap_successes = ip->swap_successes;
1386 return copy_to_user(uip, &info, sizeof(info));
1387}
1388
1389static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
1390 int version)
1391{
1392 if (version == IPC_64) {
1393 struct compat_shmid64_ds v;
1394 memset(&v, 0, sizeof(v));
1395 to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
1396 v.shm_atime = lower_32_bits(in->shm_atime);
1397 v.shm_atime_high = upper_32_bits(in->shm_atime);
1398 v.shm_dtime = lower_32_bits(in->shm_dtime);
1399 v.shm_dtime_high = upper_32_bits(in->shm_dtime);
1400 v.shm_ctime = lower_32_bits(in->shm_ctime);
1401 v.shm_ctime_high = upper_32_bits(in->shm_ctime);
1402 v.shm_segsz = in->shm_segsz;
1403 v.shm_nattch = in->shm_nattch;
1404 v.shm_cpid = in->shm_cpid;
1405 v.shm_lpid = in->shm_lpid;
1406 return copy_to_user(buf, &v, sizeof(v));
1407 } else {
1408 struct compat_shmid_ds v;
1409 memset(&v, 0, sizeof(v));
1410 to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
1411 v.shm_perm.key = in->shm_perm.key;
1412 v.shm_atime = in->shm_atime;
1413 v.shm_dtime = in->shm_dtime;
1414 v.shm_ctime = in->shm_ctime;
1415 v.shm_segsz = in->shm_segsz;
1416 v.shm_nattch = in->shm_nattch;
1417 v.shm_cpid = in->shm_cpid;
1418 v.shm_lpid = in->shm_lpid;
1419 return copy_to_user(buf, &v, sizeof(v));
1420 }
1421}
1422
1423static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
1424 int version)
1425{
1426 memset(out, 0, sizeof(*out));
1427 if (version == IPC_64) {
1428 struct compat_shmid64_ds __user *p = buf;
1429 return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
1430 } else {
1431 struct compat_shmid_ds __user *p = buf;
1432 return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
1433 }
1434}
1435
1436static long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
1437{
1438 struct ipc_namespace *ns;
1439 struct shmid64_ds sem64;
1440 int err;
1441
1442 ns = current->nsproxy->ipc_ns;
1443
1444 if (cmd < 0 || shmid < 0)
1445 return -EINVAL;
1446
1447 switch (cmd) {
1448 case IPC_INFO: {
1449 struct shminfo64 shminfo;
1450 err = shmctl_ipc_info(ns, &shminfo);
1451 if (err < 0)
1452 return err;
1453 if (copy_compat_shminfo_to_user(uptr, &shminfo, version))
1454 err = -EFAULT;
1455 return err;
1456 }
1457 case SHM_INFO: {
1458 struct shm_info shm_info;
1459 err = shmctl_shm_info(ns, &shm_info);
1460 if (err < 0)
1461 return err;
1462 if (put_compat_shm_info(&shm_info, uptr))
1463 err = -EFAULT;
1464 return err;
1465 }
1466 case IPC_STAT:
1467 case SHM_STAT_ANY:
1468 case SHM_STAT:
1469 err = shmctl_stat(ns, shmid, cmd, &sem64);
1470 if (err < 0)
1471 return err;
1472 if (copy_compat_shmid_to_user(uptr, &sem64, version))
1473 err = -EFAULT;
1474 return err;
1475
1476 case IPC_SET:
1477 if (copy_compat_shmid_from_user(&sem64, uptr, version))
1478 return -EFAULT;
1479 fallthrough;
1480 case IPC_RMID:
1481 return shmctl_down(ns, shmid, cmd, &sem64);
1482 case SHM_LOCK:
1483 case SHM_UNLOCK:
1484 return shmctl_do_lock(ns, shmid, cmd);
1485 default:
1486 return -EINVAL;
1487 }
1488 return err;
1489}
1490
1491COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
1492{
1493 return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
1494}
1495
1496#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1497long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
1498{
1499 int version = compat_ipc_parse_version(&cmd);
1500
1501 return compat_ksys_shmctl(shmid, cmd, uptr, version);
1502}
1503
1504COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
1505{
1506 return compat_ksys_old_shmctl(shmid, cmd, uptr);
1507}
1508#endif
1509#endif
1510
1511/*
1512 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1513 *
1514 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1515 * "raddr" thing points to kernel space, and there has to be a wrapper around
1516 * this.
1517 */
1518long do_shmat(int shmid, char __user *shmaddr, int shmflg,
1519 ulong *raddr, unsigned long shmlba)
1520{
1521 struct shmid_kernel *shp;
1522 unsigned long addr = (unsigned long)shmaddr;
1523 unsigned long size;
1524 struct file *file, *base;
1525 int err;
1526 unsigned long flags = MAP_SHARED;
1527 unsigned long prot;
1528 int acc_mode;
1529 struct ipc_namespace *ns;
1530 struct shm_file_data *sfd;
1531 int f_flags;
1532 unsigned long populate = 0;
1533
1534 err = -EINVAL;
1535 if (shmid < 0)
1536 goto out;
1537
1538 if (addr) {
1539 if (addr & (shmlba - 1)) {
1540 if (shmflg & SHM_RND) {
1541 addr &= ~(shmlba - 1); /* round down */
1542
1543 /*
1544 * Ensure that the round-down is non-nil
1545 * when remapping. This can happen for
1546 * cases when addr < shmlba.
1547 */
1548 if (!addr && (shmflg & SHM_REMAP))
1549 goto out;
1550 } else
1551#ifndef __ARCH_FORCE_SHMLBA
1552 if (addr & ~PAGE_MASK)
1553#endif
1554 goto out;
1555 }
1556
1557 flags |= MAP_FIXED;
1558 } else if ((shmflg & SHM_REMAP))
1559 goto out;
1560
1561 if (shmflg & SHM_RDONLY) {
1562 prot = PROT_READ;
1563 acc_mode = S_IRUGO;
1564 f_flags = O_RDONLY;
1565 } else {
1566 prot = PROT_READ | PROT_WRITE;
1567 acc_mode = S_IRUGO | S_IWUGO;
1568 f_flags = O_RDWR;
1569 }
1570 if (shmflg & SHM_EXEC) {
1571 prot |= PROT_EXEC;
1572 acc_mode |= S_IXUGO;
1573 }
1574
1575 /*
1576 * We cannot rely on the fs check since SYSV IPC does have an
1577 * additional creator id...
1578 */
1579 ns = current->nsproxy->ipc_ns;
1580 rcu_read_lock();
1581 shp = shm_obtain_object_check(ns, shmid);
1582 if (IS_ERR(shp)) {
1583 err = PTR_ERR(shp);
1584 goto out_unlock;
1585 }
1586
1587 err = -EACCES;
1588 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1589 goto out_unlock;
1590
1591 err = security_shm_shmat(&shp->shm_perm, shmaddr, shmflg);
1592 if (err)
1593 goto out_unlock;
1594
1595 ipc_lock_object(&shp->shm_perm);
1596
1597 /* check if shm_destroy() is tearing down shp */
1598 if (!ipc_valid_object(&shp->shm_perm)) {
1599 ipc_unlock_object(&shp->shm_perm);
1600 err = -EIDRM;
1601 goto out_unlock;
1602 }
1603
1604 /*
1605 * We need to take a reference to the real shm file to prevent the
1606 * pointer from becoming stale in cases where the lifetime of the outer
1607 * file extends beyond that of the shm segment. It's not usually
1608 * possible, but it can happen during remap_file_pages() emulation as
1609 * that unmaps the memory, then does ->mmap() via file reference only.
1610 * We'll deny the ->mmap() if the shm segment was since removed, but to
1611 * detect shm ID reuse we need to compare the file pointers.
1612 */
1613 base = get_file(shp->shm_file);
1614 shp->shm_nattch++;
1615 size = i_size_read(file_inode(base));
1616 ipc_unlock_object(&shp->shm_perm);
1617 rcu_read_unlock();
1618
1619 err = -ENOMEM;
1620 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1621 if (!sfd) {
1622 fput(base);
1623 goto out_nattch;
1624 }
1625
1626 file = alloc_file_clone(base, f_flags,
1627 is_file_hugepages(base) ?
1628 &shm_file_operations_huge :
1629 &shm_file_operations);
1630 err = PTR_ERR(file);
1631 if (IS_ERR(file)) {
1632 kfree(sfd);
1633 fput(base);
1634 goto out_nattch;
1635 }
1636
1637 sfd->id = shp->shm_perm.id;
1638 sfd->ns = get_ipc_ns(ns);
1639 sfd->file = base;
1640 sfd->vm_ops = NULL;
1641 file->private_data = sfd;
1642
1643 err = security_mmap_file(file, prot, flags);
1644 if (err)
1645 goto out_fput;
1646
1647 if (mmap_write_lock_killable(current->mm)) {
1648 err = -EINTR;
1649 goto out_fput;
1650 }
1651
1652 if (addr && !(shmflg & SHM_REMAP)) {
1653 err = -EINVAL;
1654 if (addr + size < addr)
1655 goto invalid;
1656
1657 if (find_vma_intersection(current->mm, addr, addr + size))
1658 goto invalid;
1659 }
1660
1661 addr = do_mmap(file, addr, size, prot, flags, 0, 0, &populate, NULL);
1662 *raddr = addr;
1663 err = 0;
1664 if (IS_ERR_VALUE(addr))
1665 err = (long)addr;
1666invalid:
1667 mmap_write_unlock(current->mm);
1668 if (populate)
1669 mm_populate(addr, populate);
1670
1671out_fput:
1672 fput(file);
1673
1674out_nattch:
1675 down_write(&shm_ids(ns).rwsem);
1676 shp = shm_lock(ns, shmid);
1677 shp->shm_nattch--;
1678
1679 if (shm_may_destroy(shp))
1680 shm_destroy(ns, shp);
1681 else
1682 shm_unlock(shp);
1683 up_write(&shm_ids(ns).rwsem);
1684 return err;
1685
1686out_unlock:
1687 rcu_read_unlock();
1688out:
1689 return err;
1690}
1691
1692SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1693{
1694 unsigned long ret;
1695 long err;
1696
1697 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1698 if (err)
1699 return err;
1700 force_successful_syscall_return();
1701 return (long)ret;
1702}
1703
1704#ifdef CONFIG_COMPAT
1705
1706#ifndef COMPAT_SHMLBA
1707#define COMPAT_SHMLBA SHMLBA
1708#endif
1709
1710COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
1711{
1712 unsigned long ret;
1713 long err;
1714
1715 err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
1716 if (err)
1717 return err;
1718 force_successful_syscall_return();
1719 return (long)ret;
1720}
1721#endif
1722
1723/*
1724 * detach and kill segment if marked destroyed.
1725 * The work is done in shm_close.
1726 */
1727long ksys_shmdt(char __user *shmaddr)
1728{
1729 struct mm_struct *mm = current->mm;
1730 struct vm_area_struct *vma;
1731 unsigned long addr = (unsigned long)shmaddr;
1732 int retval = -EINVAL;
1733#ifdef CONFIG_MMU
1734 loff_t size = 0;
1735 struct file *file;
1736 VMA_ITERATOR(vmi, mm, addr);
1737#endif
1738
1739 if (addr & ~PAGE_MASK)
1740 return retval;
1741
1742 if (mmap_write_lock_killable(mm))
1743 return -EINTR;
1744
1745 /*
1746 * This function tries to be smart and unmap shm segments that
1747 * were modified by partial mlock or munmap calls:
1748 * - It first determines the size of the shm segment that should be
1749 * unmapped: It searches for a vma that is backed by shm and that
1750 * started at address shmaddr. It records it's size and then unmaps
1751 * it.
1752 * - Then it unmaps all shm vmas that started at shmaddr and that
1753 * are within the initially determined size and that are from the
1754 * same shm segment from which we determined the size.
1755 * Errors from do_munmap are ignored: the function only fails if
1756 * it's called with invalid parameters or if it's called to unmap
1757 * a part of a vma. Both calls in this function are for full vmas,
1758 * the parameters are directly copied from the vma itself and always
1759 * valid - therefore do_munmap cannot fail. (famous last words?)
1760 */
1761 /*
1762 * If it had been mremap()'d, the starting address would not
1763 * match the usual checks anyway. So assume all vma's are
1764 * above the starting address given.
1765 */
1766
1767#ifdef CONFIG_MMU
1768 for_each_vma(vmi, vma) {
1769 /*
1770 * Check if the starting address would match, i.e. it's
1771 * a fragment created by mprotect() and/or munmap(), or it
1772 * otherwise it starts at this address with no hassles.
1773 */
1774 if ((vma->vm_ops == &shm_vm_ops) &&
1775 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1776
1777 /*
1778 * Record the file of the shm segment being
1779 * unmapped. With mremap(), someone could place
1780 * page from another segment but with equal offsets
1781 * in the range we are unmapping.
1782 */
1783 file = vma->vm_file;
1784 size = i_size_read(file_inode(vma->vm_file));
1785 do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
1786 NULL, false);
1787 /*
1788 * We discovered the size of the shm segment, so
1789 * break out of here and fall through to the next
1790 * loop that uses the size information to stop
1791 * searching for matching vma's.
1792 */
1793 retval = 0;
1794 vma = vma_next(&vmi);
1795 break;
1796 }
1797 }
1798
1799 /*
1800 * We need look no further than the maximum address a fragment
1801 * could possibly have landed at. Also cast things to loff_t to
1802 * prevent overflows and make comparisons vs. equal-width types.
1803 */
1804 size = PAGE_ALIGN(size);
1805 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1806 /* finding a matching vma now does not alter retval */
1807 if ((vma->vm_ops == &shm_vm_ops) &&
1808 ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1809 (vma->vm_file == file)) {
1810 do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
1811 NULL, false);
1812 }
1813
1814 vma = vma_next(&vmi);
1815 }
1816
1817#else /* CONFIG_MMU */
1818 vma = vma_lookup(mm, addr);
1819 /* under NOMMU conditions, the exact address to be destroyed must be
1820 * given
1821 */
1822 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1823 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1824 retval = 0;
1825 }
1826
1827#endif
1828
1829 mmap_write_unlock(mm);
1830 return retval;
1831}
1832
1833SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1834{
1835 return ksys_shmdt(shmaddr);
1836}
1837
1838#ifdef CONFIG_PROC_FS
1839static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1840{
1841 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1842 struct user_namespace *user_ns = seq_user_ns(s);
1843 struct kern_ipc_perm *ipcp = it;
1844 struct shmid_kernel *shp;
1845 unsigned long rss = 0, swp = 0;
1846
1847 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
1848 shm_add_rss_swap(shp, &rss, &swp);
1849
1850#if BITS_PER_LONG <= 32
1851#define SIZE_SPEC "%10lu"
1852#else
1853#define SIZE_SPEC "%21lu"
1854#endif
1855
1856 seq_printf(s,
1857 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1858 "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
1859 SIZE_SPEC " " SIZE_SPEC "\n",
1860 shp->shm_perm.key,
1861 shp->shm_perm.id,
1862 shp->shm_perm.mode,
1863 shp->shm_segsz,
1864 pid_nr_ns(shp->shm_cprid, pid_ns),
1865 pid_nr_ns(shp->shm_lprid, pid_ns),
1866 shp->shm_nattch,
1867 from_kuid_munged(user_ns, shp->shm_perm.uid),
1868 from_kgid_munged(user_ns, shp->shm_perm.gid),
1869 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1870 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1871 shp->shm_atim,
1872 shp->shm_dtim,
1873 shp->shm_ctim,
1874 rss * PAGE_SIZE,
1875 swp * PAGE_SIZE);
1876
1877 return 0;
1878}
1879#endif