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1/*
2 * linux/ipc/shm.c
3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
4 * Many improvements/fixes by Bruno Haible.
5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
7 *
8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
15 *
16 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
18 *
19 * namespaces support
20 * OpenVZ, SWsoft Inc.
21 * Pavel Emelianov <xemul@openvz.org>
22 */
23
24#include <linux/slab.h>
25#include <linux/mm.h>
26#include <linux/hugetlb.h>
27#include <linux/shm.h>
28#include <linux/init.h>
29#include <linux/file.h>
30#include <linux/mman.h>
31#include <linux/shmem_fs.h>
32#include <linux/security.h>
33#include <linux/syscalls.h>
34#include <linux/audit.h>
35#include <linux/capability.h>
36#include <linux/ptrace.h>
37#include <linux/seq_file.h>
38#include <linux/rwsem.h>
39#include <linux/nsproxy.h>
40#include <linux/mount.h>
41#include <linux/ipc_namespace.h>
42
43#include <asm/uaccess.h>
44
45#include "util.h"
46
47struct shm_file_data {
48 int id;
49 struct ipc_namespace *ns;
50 struct file *file;
51 const struct vm_operations_struct *vm_ops;
52};
53
54#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
55
56static const struct file_operations shm_file_operations;
57static const struct vm_operations_struct shm_vm_ops;
58
59#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
60
61#define shm_unlock(shp) \
62 ipc_unlock(&(shp)->shm_perm)
63
64static int newseg(struct ipc_namespace *, struct ipc_params *);
65static void shm_open(struct vm_area_struct *vma);
66static void shm_close(struct vm_area_struct *vma);
67static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
68#ifdef CONFIG_PROC_FS
69static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
70#endif
71
72void shm_init_ns(struct ipc_namespace *ns)
73{
74 ns->shm_ctlmax = SHMMAX;
75 ns->shm_ctlall = SHMALL;
76 ns->shm_ctlmni = SHMMNI;
77 ns->shm_rmid_forced = 0;
78 ns->shm_tot = 0;
79 ipc_init_ids(&shm_ids(ns));
80}
81
82/*
83 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
84 * Only shm_ids.rw_mutex remains locked on exit.
85 */
86static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
87{
88 struct shmid_kernel *shp;
89 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
90
91 if (shp->shm_nattch){
92 shp->shm_perm.mode |= SHM_DEST;
93 /* Do not find it any more */
94 shp->shm_perm.key = IPC_PRIVATE;
95 shm_unlock(shp);
96 } else
97 shm_destroy(ns, shp);
98}
99
100#ifdef CONFIG_IPC_NS
101void shm_exit_ns(struct ipc_namespace *ns)
102{
103 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
104 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
105}
106#endif
107
108static int __init ipc_ns_init(void)
109{
110 shm_init_ns(&init_ipc_ns);
111 return 0;
112}
113
114pure_initcall(ipc_ns_init);
115
116void __init shm_init (void)
117{
118 ipc_init_proc_interface("sysvipc/shm",
119#if BITS_PER_LONG <= 32
120 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
121#else
122 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
123#endif
124 IPC_SHM_IDS, sysvipc_shm_proc_show);
125}
126
127/*
128 * shm_lock_(check_) routines are called in the paths where the rw_mutex
129 * is not necessarily held.
130 */
131static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
132{
133 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
134
135 if (IS_ERR(ipcp))
136 return (struct shmid_kernel *)ipcp;
137
138 return container_of(ipcp, struct shmid_kernel, shm_perm);
139}
140
141static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
142{
143 rcu_read_lock();
144 spin_lock(&ipcp->shm_perm.lock);
145}
146
147static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
148 int id)
149{
150 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
151
152 if (IS_ERR(ipcp))
153 return (struct shmid_kernel *)ipcp;
154
155 return container_of(ipcp, struct shmid_kernel, shm_perm);
156}
157
158static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
159{
160 ipc_rmid(&shm_ids(ns), &s->shm_perm);
161}
162
163
164/* This is called by fork, once for every shm attach. */
165static void shm_open(struct vm_area_struct *vma)
166{
167 struct file *file = vma->vm_file;
168 struct shm_file_data *sfd = shm_file_data(file);
169 struct shmid_kernel *shp;
170
171 shp = shm_lock(sfd->ns, sfd->id);
172 BUG_ON(IS_ERR(shp));
173 shp->shm_atim = get_seconds();
174 shp->shm_lprid = task_tgid_vnr(current);
175 shp->shm_nattch++;
176 shm_unlock(shp);
177}
178
179/*
180 * shm_destroy - free the struct shmid_kernel
181 *
182 * @ns: namespace
183 * @shp: struct to free
184 *
185 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
186 * but returns with shp unlocked and freed.
187 */
188static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
189{
190 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
191 shm_rmid(ns, shp);
192 shm_unlock(shp);
193 if (!is_file_hugepages(shp->shm_file))
194 shmem_lock(shp->shm_file, 0, shp->mlock_user);
195 else if (shp->mlock_user)
196 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
197 shp->mlock_user);
198 fput (shp->shm_file);
199 security_shm_free(shp);
200 ipc_rcu_putref(shp);
201}
202
203/*
204 * shm_may_destroy - identifies whether shm segment should be destroyed now
205 *
206 * Returns true if and only if there are no active users of the segment and
207 * one of the following is true:
208 *
209 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
210 *
211 * 2) sysctl kernel.shm_rmid_forced is set to 1.
212 */
213static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
214{
215 return (shp->shm_nattch == 0) &&
216 (ns->shm_rmid_forced ||
217 (shp->shm_perm.mode & SHM_DEST));
218}
219
220/*
221 * remove the attach descriptor vma.
222 * free memory for segment if it is marked destroyed.
223 * The descriptor has already been removed from the current->mm->mmap list
224 * and will later be kfree()d.
225 */
226static void shm_close(struct vm_area_struct *vma)
227{
228 struct file * file = vma->vm_file;
229 struct shm_file_data *sfd = shm_file_data(file);
230 struct shmid_kernel *shp;
231 struct ipc_namespace *ns = sfd->ns;
232
233 down_write(&shm_ids(ns).rw_mutex);
234 /* remove from the list of attaches of the shm segment */
235 shp = shm_lock(ns, sfd->id);
236 BUG_ON(IS_ERR(shp));
237 shp->shm_lprid = task_tgid_vnr(current);
238 shp->shm_dtim = get_seconds();
239 shp->shm_nattch--;
240 if (shm_may_destroy(ns, shp))
241 shm_destroy(ns, shp);
242 else
243 shm_unlock(shp);
244 up_write(&shm_ids(ns).rw_mutex);
245}
246
247/* Called with ns->shm_ids(ns).rw_mutex locked */
248static int shm_try_destroy_current(int id, void *p, void *data)
249{
250 struct ipc_namespace *ns = data;
251 struct kern_ipc_perm *ipcp = p;
252 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
253
254 if (shp->shm_creator != current)
255 return 0;
256
257 /*
258 * Mark it as orphaned to destroy the segment when
259 * kernel.shm_rmid_forced is changed.
260 * It is noop if the following shm_may_destroy() returns true.
261 */
262 shp->shm_creator = NULL;
263
264 /*
265 * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID
266 * is not set, it shouldn't be deleted here.
267 */
268 if (!ns->shm_rmid_forced)
269 return 0;
270
271 if (shm_may_destroy(ns, shp)) {
272 shm_lock_by_ptr(shp);
273 shm_destroy(ns, shp);
274 }
275 return 0;
276}
277
278/* Called with ns->shm_ids(ns).rw_mutex locked */
279static int shm_try_destroy_orphaned(int id, void *p, void *data)
280{
281 struct ipc_namespace *ns = data;
282 struct kern_ipc_perm *ipcp = p;
283 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
284
285 /*
286 * We want to destroy segments without users and with already
287 * exit'ed originating process.
288 *
289 * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
290 */
291 if (shp->shm_creator != NULL)
292 return 0;
293
294 if (shm_may_destroy(ns, shp)) {
295 shm_lock_by_ptr(shp);
296 shm_destroy(ns, shp);
297 }
298 return 0;
299}
300
301void shm_destroy_orphaned(struct ipc_namespace *ns)
302{
303 down_write(&shm_ids(ns).rw_mutex);
304 if (shm_ids(ns).in_use)
305 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
306 up_write(&shm_ids(ns).rw_mutex);
307}
308
309
310void exit_shm(struct task_struct *task)
311{
312 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
313
314 if (shm_ids(ns).in_use == 0)
315 return;
316
317 /* Destroy all already created segments, but not mapped yet */
318 down_write(&shm_ids(ns).rw_mutex);
319 if (shm_ids(ns).in_use)
320 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
321 up_write(&shm_ids(ns).rw_mutex);
322}
323
324static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
325{
326 struct file *file = vma->vm_file;
327 struct shm_file_data *sfd = shm_file_data(file);
328
329 return sfd->vm_ops->fault(vma, vmf);
330}
331
332#ifdef CONFIG_NUMA
333static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
334{
335 struct file *file = vma->vm_file;
336 struct shm_file_data *sfd = shm_file_data(file);
337 int err = 0;
338 if (sfd->vm_ops->set_policy)
339 err = sfd->vm_ops->set_policy(vma, new);
340 return err;
341}
342
343static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
344 unsigned long addr)
345{
346 struct file *file = vma->vm_file;
347 struct shm_file_data *sfd = shm_file_data(file);
348 struct mempolicy *pol = NULL;
349
350 if (sfd->vm_ops->get_policy)
351 pol = sfd->vm_ops->get_policy(vma, addr);
352 else if (vma->vm_policy)
353 pol = vma->vm_policy;
354
355 return pol;
356}
357#endif
358
359static int shm_mmap(struct file * file, struct vm_area_struct * vma)
360{
361 struct shm_file_data *sfd = shm_file_data(file);
362 int ret;
363
364 ret = sfd->file->f_op->mmap(sfd->file, vma);
365 if (ret != 0)
366 return ret;
367 sfd->vm_ops = vma->vm_ops;
368#ifdef CONFIG_MMU
369 BUG_ON(!sfd->vm_ops->fault);
370#endif
371 vma->vm_ops = &shm_vm_ops;
372 shm_open(vma);
373
374 return ret;
375}
376
377static int shm_release(struct inode *ino, struct file *file)
378{
379 struct shm_file_data *sfd = shm_file_data(file);
380
381 put_ipc_ns(sfd->ns);
382 shm_file_data(file) = NULL;
383 kfree(sfd);
384 return 0;
385}
386
387static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
388{
389 struct shm_file_data *sfd = shm_file_data(file);
390
391 if (!sfd->file->f_op->fsync)
392 return -EINVAL;
393 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
394}
395
396static long shm_fallocate(struct file *file, int mode, loff_t offset,
397 loff_t len)
398{
399 struct shm_file_data *sfd = shm_file_data(file);
400
401 if (!sfd->file->f_op->fallocate)
402 return -EOPNOTSUPP;
403 return sfd->file->f_op->fallocate(file, mode, offset, len);
404}
405
406static unsigned long shm_get_unmapped_area(struct file *file,
407 unsigned long addr, unsigned long len, unsigned long pgoff,
408 unsigned long flags)
409{
410 struct shm_file_data *sfd = shm_file_data(file);
411 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
412 pgoff, flags);
413}
414
415static const struct file_operations shm_file_operations = {
416 .mmap = shm_mmap,
417 .fsync = shm_fsync,
418 .release = shm_release,
419#ifndef CONFIG_MMU
420 .get_unmapped_area = shm_get_unmapped_area,
421#endif
422 .llseek = noop_llseek,
423 .fallocate = shm_fallocate,
424};
425
426static const struct file_operations shm_file_operations_huge = {
427 .mmap = shm_mmap,
428 .fsync = shm_fsync,
429 .release = shm_release,
430 .get_unmapped_area = shm_get_unmapped_area,
431 .llseek = noop_llseek,
432 .fallocate = shm_fallocate,
433};
434
435int is_file_shm_hugepages(struct file *file)
436{
437 return file->f_op == &shm_file_operations_huge;
438}
439
440static const struct vm_operations_struct shm_vm_ops = {
441 .open = shm_open, /* callback for a new vm-area open */
442 .close = shm_close, /* callback for when the vm-area is released */
443 .fault = shm_fault,
444#if defined(CONFIG_NUMA)
445 .set_policy = shm_set_policy,
446 .get_policy = shm_get_policy,
447#endif
448};
449
450/**
451 * newseg - Create a new shared memory segment
452 * @ns: namespace
453 * @params: ptr to the structure that contains key, size and shmflg
454 *
455 * Called with shm_ids.rw_mutex held as a writer.
456 */
457
458static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
459{
460 key_t key = params->key;
461 int shmflg = params->flg;
462 size_t size = params->u.size;
463 int error;
464 struct shmid_kernel *shp;
465 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
466 struct file * file;
467 char name[13];
468 int id;
469 vm_flags_t acctflag = 0;
470
471 if (size < SHMMIN || size > ns->shm_ctlmax)
472 return -EINVAL;
473
474 if (ns->shm_tot + numpages > ns->shm_ctlall)
475 return -ENOSPC;
476
477 shp = ipc_rcu_alloc(sizeof(*shp));
478 if (!shp)
479 return -ENOMEM;
480
481 shp->shm_perm.key = key;
482 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
483 shp->mlock_user = NULL;
484
485 shp->shm_perm.security = NULL;
486 error = security_shm_alloc(shp);
487 if (error) {
488 ipc_rcu_putref(shp);
489 return error;
490 }
491
492 sprintf (name, "SYSV%08x", key);
493 if (shmflg & SHM_HUGETLB) {
494 /* hugetlb_file_setup applies strict accounting */
495 if (shmflg & SHM_NORESERVE)
496 acctflag = VM_NORESERVE;
497 file = hugetlb_file_setup(name, 0, size, acctflag,
498 &shp->mlock_user, HUGETLB_SHMFS_INODE);
499 } else {
500 /*
501 * Do not allow no accounting for OVERCOMMIT_NEVER, even
502 * if it's asked for.
503 */
504 if ((shmflg & SHM_NORESERVE) &&
505 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
506 acctflag = VM_NORESERVE;
507 file = shmem_file_setup(name, size, acctflag);
508 }
509 error = PTR_ERR(file);
510 if (IS_ERR(file))
511 goto no_file;
512
513 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
514 if (id < 0) {
515 error = id;
516 goto no_id;
517 }
518
519 shp->shm_cprid = task_tgid_vnr(current);
520 shp->shm_lprid = 0;
521 shp->shm_atim = shp->shm_dtim = 0;
522 shp->shm_ctim = get_seconds();
523 shp->shm_segsz = size;
524 shp->shm_nattch = 0;
525 shp->shm_file = file;
526 shp->shm_creator = current;
527 /*
528 * shmid gets reported as "inode#" in /proc/pid/maps.
529 * proc-ps tools use this. Changing this will break them.
530 */
531 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
532
533 ns->shm_tot += numpages;
534 error = shp->shm_perm.id;
535 shm_unlock(shp);
536 return error;
537
538no_id:
539 if (is_file_hugepages(file) && shp->mlock_user)
540 user_shm_unlock(size, shp->mlock_user);
541 fput(file);
542no_file:
543 security_shm_free(shp);
544 ipc_rcu_putref(shp);
545 return error;
546}
547
548/*
549 * Called with shm_ids.rw_mutex and ipcp locked.
550 */
551static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
552{
553 struct shmid_kernel *shp;
554
555 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
556 return security_shm_associate(shp, shmflg);
557}
558
559/*
560 * Called with shm_ids.rw_mutex and ipcp locked.
561 */
562static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
563 struct ipc_params *params)
564{
565 struct shmid_kernel *shp;
566
567 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
568 if (shp->shm_segsz < params->u.size)
569 return -EINVAL;
570
571 return 0;
572}
573
574SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
575{
576 struct ipc_namespace *ns;
577 struct ipc_ops shm_ops;
578 struct ipc_params shm_params;
579
580 ns = current->nsproxy->ipc_ns;
581
582 shm_ops.getnew = newseg;
583 shm_ops.associate = shm_security;
584 shm_ops.more_checks = shm_more_checks;
585
586 shm_params.key = key;
587 shm_params.flg = shmflg;
588 shm_params.u.size = size;
589
590 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
591}
592
593static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
594{
595 switch(version) {
596 case IPC_64:
597 return copy_to_user(buf, in, sizeof(*in));
598 case IPC_OLD:
599 {
600 struct shmid_ds out;
601
602 memset(&out, 0, sizeof(out));
603 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
604 out.shm_segsz = in->shm_segsz;
605 out.shm_atime = in->shm_atime;
606 out.shm_dtime = in->shm_dtime;
607 out.shm_ctime = in->shm_ctime;
608 out.shm_cpid = in->shm_cpid;
609 out.shm_lpid = in->shm_lpid;
610 out.shm_nattch = in->shm_nattch;
611
612 return copy_to_user(buf, &out, sizeof(out));
613 }
614 default:
615 return -EINVAL;
616 }
617}
618
619static inline unsigned long
620copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
621{
622 switch(version) {
623 case IPC_64:
624 if (copy_from_user(out, buf, sizeof(*out)))
625 return -EFAULT;
626 return 0;
627 case IPC_OLD:
628 {
629 struct shmid_ds tbuf_old;
630
631 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
632 return -EFAULT;
633
634 out->shm_perm.uid = tbuf_old.shm_perm.uid;
635 out->shm_perm.gid = tbuf_old.shm_perm.gid;
636 out->shm_perm.mode = tbuf_old.shm_perm.mode;
637
638 return 0;
639 }
640 default:
641 return -EINVAL;
642 }
643}
644
645static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
646{
647 switch(version) {
648 case IPC_64:
649 return copy_to_user(buf, in, sizeof(*in));
650 case IPC_OLD:
651 {
652 struct shminfo out;
653
654 if(in->shmmax > INT_MAX)
655 out.shmmax = INT_MAX;
656 else
657 out.shmmax = (int)in->shmmax;
658
659 out.shmmin = in->shmmin;
660 out.shmmni = in->shmmni;
661 out.shmseg = in->shmseg;
662 out.shmall = in->shmall;
663
664 return copy_to_user(buf, &out, sizeof(out));
665 }
666 default:
667 return -EINVAL;
668 }
669}
670
671/*
672 * Calculate and add used RSS and swap pages of a shm.
673 * Called with shm_ids.rw_mutex held as a reader
674 */
675static void shm_add_rss_swap(struct shmid_kernel *shp,
676 unsigned long *rss_add, unsigned long *swp_add)
677{
678 struct inode *inode;
679
680 inode = shp->shm_file->f_path.dentry->d_inode;
681
682 if (is_file_hugepages(shp->shm_file)) {
683 struct address_space *mapping = inode->i_mapping;
684 struct hstate *h = hstate_file(shp->shm_file);
685 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
686 } else {
687#ifdef CONFIG_SHMEM
688 struct shmem_inode_info *info = SHMEM_I(inode);
689 spin_lock(&info->lock);
690 *rss_add += inode->i_mapping->nrpages;
691 *swp_add += info->swapped;
692 spin_unlock(&info->lock);
693#else
694 *rss_add += inode->i_mapping->nrpages;
695#endif
696 }
697}
698
699/*
700 * Called with shm_ids.rw_mutex held as a reader
701 */
702static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
703 unsigned long *swp)
704{
705 int next_id;
706 int total, in_use;
707
708 *rss = 0;
709 *swp = 0;
710
711 in_use = shm_ids(ns).in_use;
712
713 for (total = 0, next_id = 0; total < in_use; next_id++) {
714 struct kern_ipc_perm *ipc;
715 struct shmid_kernel *shp;
716
717 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
718 if (ipc == NULL)
719 continue;
720 shp = container_of(ipc, struct shmid_kernel, shm_perm);
721
722 shm_add_rss_swap(shp, rss, swp);
723
724 total++;
725 }
726}
727
728/*
729 * This function handles some shmctl commands which require the rw_mutex
730 * to be held in write mode.
731 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
732 */
733static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
734 struct shmid_ds __user *buf, int version)
735{
736 struct kern_ipc_perm *ipcp;
737 struct shmid64_ds shmid64;
738 struct shmid_kernel *shp;
739 int err;
740
741 if (cmd == IPC_SET) {
742 if (copy_shmid_from_user(&shmid64, buf, version))
743 return -EFAULT;
744 }
745
746 ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
747 &shmid64.shm_perm, 0);
748 if (IS_ERR(ipcp))
749 return PTR_ERR(ipcp);
750
751 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
752
753 err = security_shm_shmctl(shp, cmd);
754 if (err)
755 goto out_unlock;
756 switch (cmd) {
757 case IPC_RMID:
758 do_shm_rmid(ns, ipcp);
759 goto out_up;
760 case IPC_SET:
761 ipc_update_perm(&shmid64.shm_perm, ipcp);
762 shp->shm_ctim = get_seconds();
763 break;
764 default:
765 err = -EINVAL;
766 }
767out_unlock:
768 shm_unlock(shp);
769out_up:
770 up_write(&shm_ids(ns).rw_mutex);
771 return err;
772}
773
774SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
775{
776 struct shmid_kernel *shp;
777 int err, version;
778 struct ipc_namespace *ns;
779
780 if (cmd < 0 || shmid < 0) {
781 err = -EINVAL;
782 goto out;
783 }
784
785 version = ipc_parse_version(&cmd);
786 ns = current->nsproxy->ipc_ns;
787
788 switch (cmd) { /* replace with proc interface ? */
789 case IPC_INFO:
790 {
791 struct shminfo64 shminfo;
792
793 err = security_shm_shmctl(NULL, cmd);
794 if (err)
795 return err;
796
797 memset(&shminfo, 0, sizeof(shminfo));
798 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
799 shminfo.shmmax = ns->shm_ctlmax;
800 shminfo.shmall = ns->shm_ctlall;
801
802 shminfo.shmmin = SHMMIN;
803 if(copy_shminfo_to_user (buf, &shminfo, version))
804 return -EFAULT;
805
806 down_read(&shm_ids(ns).rw_mutex);
807 err = ipc_get_maxid(&shm_ids(ns));
808 up_read(&shm_ids(ns).rw_mutex);
809
810 if(err<0)
811 err = 0;
812 goto out;
813 }
814 case SHM_INFO:
815 {
816 struct shm_info shm_info;
817
818 err = security_shm_shmctl(NULL, cmd);
819 if (err)
820 return err;
821
822 memset(&shm_info, 0, sizeof(shm_info));
823 down_read(&shm_ids(ns).rw_mutex);
824 shm_info.used_ids = shm_ids(ns).in_use;
825 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
826 shm_info.shm_tot = ns->shm_tot;
827 shm_info.swap_attempts = 0;
828 shm_info.swap_successes = 0;
829 err = ipc_get_maxid(&shm_ids(ns));
830 up_read(&shm_ids(ns).rw_mutex);
831 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
832 err = -EFAULT;
833 goto out;
834 }
835
836 err = err < 0 ? 0 : err;
837 goto out;
838 }
839 case SHM_STAT:
840 case IPC_STAT:
841 {
842 struct shmid64_ds tbuf;
843 int result;
844
845 if (cmd == SHM_STAT) {
846 shp = shm_lock(ns, shmid);
847 if (IS_ERR(shp)) {
848 err = PTR_ERR(shp);
849 goto out;
850 }
851 result = shp->shm_perm.id;
852 } else {
853 shp = shm_lock_check(ns, shmid);
854 if (IS_ERR(shp)) {
855 err = PTR_ERR(shp);
856 goto out;
857 }
858 result = 0;
859 }
860 err = -EACCES;
861 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
862 goto out_unlock;
863 err = security_shm_shmctl(shp, cmd);
864 if (err)
865 goto out_unlock;
866 memset(&tbuf, 0, sizeof(tbuf));
867 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
868 tbuf.shm_segsz = shp->shm_segsz;
869 tbuf.shm_atime = shp->shm_atim;
870 tbuf.shm_dtime = shp->shm_dtim;
871 tbuf.shm_ctime = shp->shm_ctim;
872 tbuf.shm_cpid = shp->shm_cprid;
873 tbuf.shm_lpid = shp->shm_lprid;
874 tbuf.shm_nattch = shp->shm_nattch;
875 shm_unlock(shp);
876 if(copy_shmid_to_user (buf, &tbuf, version))
877 err = -EFAULT;
878 else
879 err = result;
880 goto out;
881 }
882 case SHM_LOCK:
883 case SHM_UNLOCK:
884 {
885 struct file *shm_file;
886
887 shp = shm_lock_check(ns, shmid);
888 if (IS_ERR(shp)) {
889 err = PTR_ERR(shp);
890 goto out;
891 }
892
893 audit_ipc_obj(&(shp->shm_perm));
894
895 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
896 uid_t euid = current_euid();
897 err = -EPERM;
898 if (euid != shp->shm_perm.uid &&
899 euid != shp->shm_perm.cuid)
900 goto out_unlock;
901 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
902 goto out_unlock;
903 }
904
905 err = security_shm_shmctl(shp, cmd);
906 if (err)
907 goto out_unlock;
908
909 shm_file = shp->shm_file;
910 if (is_file_hugepages(shm_file))
911 goto out_unlock;
912
913 if (cmd == SHM_LOCK) {
914 struct user_struct *user = current_user();
915 err = shmem_lock(shm_file, 1, user);
916 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
917 shp->shm_perm.mode |= SHM_LOCKED;
918 shp->mlock_user = user;
919 }
920 goto out_unlock;
921 }
922
923 /* SHM_UNLOCK */
924 if (!(shp->shm_perm.mode & SHM_LOCKED))
925 goto out_unlock;
926 shmem_lock(shm_file, 0, shp->mlock_user);
927 shp->shm_perm.mode &= ~SHM_LOCKED;
928 shp->mlock_user = NULL;
929 get_file(shm_file);
930 shm_unlock(shp);
931 shmem_unlock_mapping(shm_file->f_mapping);
932 fput(shm_file);
933 goto out;
934 }
935 case IPC_RMID:
936 case IPC_SET:
937 err = shmctl_down(ns, shmid, cmd, buf, version);
938 return err;
939 default:
940 return -EINVAL;
941 }
942
943out_unlock:
944 shm_unlock(shp);
945out:
946 return err;
947}
948
949/*
950 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
951 *
952 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
953 * "raddr" thing points to kernel space, and there has to be a wrapper around
954 * this.
955 */
956long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
957{
958 struct shmid_kernel *shp;
959 unsigned long addr;
960 unsigned long size;
961 struct file * file;
962 int err;
963 unsigned long flags;
964 unsigned long prot;
965 int acc_mode;
966 unsigned long user_addr;
967 struct ipc_namespace *ns;
968 struct shm_file_data *sfd;
969 struct path path;
970 fmode_t f_mode;
971
972 err = -EINVAL;
973 if (shmid < 0)
974 goto out;
975 else if ((addr = (ulong)shmaddr)) {
976 if (addr & (SHMLBA-1)) {
977 if (shmflg & SHM_RND)
978 addr &= ~(SHMLBA-1); /* round down */
979 else
980#ifndef __ARCH_FORCE_SHMLBA
981 if (addr & ~PAGE_MASK)
982#endif
983 goto out;
984 }
985 flags = MAP_SHARED | MAP_FIXED;
986 } else {
987 if ((shmflg & SHM_REMAP))
988 goto out;
989
990 flags = MAP_SHARED;
991 }
992
993 if (shmflg & SHM_RDONLY) {
994 prot = PROT_READ;
995 acc_mode = S_IRUGO;
996 f_mode = FMODE_READ;
997 } else {
998 prot = PROT_READ | PROT_WRITE;
999 acc_mode = S_IRUGO | S_IWUGO;
1000 f_mode = FMODE_READ | FMODE_WRITE;
1001 }
1002 if (shmflg & SHM_EXEC) {
1003 prot |= PROT_EXEC;
1004 acc_mode |= S_IXUGO;
1005 }
1006
1007 /*
1008 * We cannot rely on the fs check since SYSV IPC does have an
1009 * additional creator id...
1010 */
1011 ns = current->nsproxy->ipc_ns;
1012 shp = shm_lock_check(ns, shmid);
1013 if (IS_ERR(shp)) {
1014 err = PTR_ERR(shp);
1015 goto out;
1016 }
1017
1018 err = -EACCES;
1019 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1020 goto out_unlock;
1021
1022 err = security_shm_shmat(shp, shmaddr, shmflg);
1023 if (err)
1024 goto out_unlock;
1025
1026 path = shp->shm_file->f_path;
1027 path_get(&path);
1028 shp->shm_nattch++;
1029 size = i_size_read(path.dentry->d_inode);
1030 shm_unlock(shp);
1031
1032 err = -ENOMEM;
1033 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1034 if (!sfd)
1035 goto out_put_dentry;
1036
1037 file = alloc_file(&path, f_mode,
1038 is_file_hugepages(shp->shm_file) ?
1039 &shm_file_operations_huge :
1040 &shm_file_operations);
1041 if (!file)
1042 goto out_free;
1043
1044 file->private_data = sfd;
1045 file->f_mapping = shp->shm_file->f_mapping;
1046 sfd->id = shp->shm_perm.id;
1047 sfd->ns = get_ipc_ns(ns);
1048 sfd->file = shp->shm_file;
1049 sfd->vm_ops = NULL;
1050
1051 err = security_mmap_file(file, prot, flags);
1052 if (err)
1053 goto out_fput;
1054
1055 down_write(¤t->mm->mmap_sem);
1056 if (addr && !(shmflg & SHM_REMAP)) {
1057 err = -EINVAL;
1058 if (find_vma_intersection(current->mm, addr, addr + size))
1059 goto invalid;
1060 /*
1061 * If shm segment goes below stack, make sure there is some
1062 * space left for the stack to grow (at least 4 pages).
1063 */
1064 if (addr < current->mm->start_stack &&
1065 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1066 goto invalid;
1067 }
1068
1069 user_addr = do_mmap_pgoff(file, addr, size, prot, flags, 0);
1070 *raddr = user_addr;
1071 err = 0;
1072 if (IS_ERR_VALUE(user_addr))
1073 err = (long)user_addr;
1074invalid:
1075 up_write(¤t->mm->mmap_sem);
1076
1077out_fput:
1078 fput(file);
1079
1080out_nattch:
1081 down_write(&shm_ids(ns).rw_mutex);
1082 shp = shm_lock(ns, shmid);
1083 BUG_ON(IS_ERR(shp));
1084 shp->shm_nattch--;
1085 if (shm_may_destroy(ns, shp))
1086 shm_destroy(ns, shp);
1087 else
1088 shm_unlock(shp);
1089 up_write(&shm_ids(ns).rw_mutex);
1090
1091out:
1092 return err;
1093
1094out_unlock:
1095 shm_unlock(shp);
1096 goto out;
1097
1098out_free:
1099 kfree(sfd);
1100out_put_dentry:
1101 path_put(&path);
1102 goto out_nattch;
1103}
1104
1105SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1106{
1107 unsigned long ret;
1108 long err;
1109
1110 err = do_shmat(shmid, shmaddr, shmflg, &ret);
1111 if (err)
1112 return err;
1113 force_successful_syscall_return();
1114 return (long)ret;
1115}
1116
1117/*
1118 * detach and kill segment if marked destroyed.
1119 * The work is done in shm_close.
1120 */
1121SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1122{
1123 struct mm_struct *mm = current->mm;
1124 struct vm_area_struct *vma;
1125 unsigned long addr = (unsigned long)shmaddr;
1126 int retval = -EINVAL;
1127#ifdef CONFIG_MMU
1128 loff_t size = 0;
1129 struct vm_area_struct *next;
1130#endif
1131
1132 if (addr & ~PAGE_MASK)
1133 return retval;
1134
1135 down_write(&mm->mmap_sem);
1136
1137 /*
1138 * This function tries to be smart and unmap shm segments that
1139 * were modified by partial mlock or munmap calls:
1140 * - It first determines the size of the shm segment that should be
1141 * unmapped: It searches for a vma that is backed by shm and that
1142 * started at address shmaddr. It records it's size and then unmaps
1143 * it.
1144 * - Then it unmaps all shm vmas that started at shmaddr and that
1145 * are within the initially determined size.
1146 * Errors from do_munmap are ignored: the function only fails if
1147 * it's called with invalid parameters or if it's called to unmap
1148 * a part of a vma. Both calls in this function are for full vmas,
1149 * the parameters are directly copied from the vma itself and always
1150 * valid - therefore do_munmap cannot fail. (famous last words?)
1151 */
1152 /*
1153 * If it had been mremap()'d, the starting address would not
1154 * match the usual checks anyway. So assume all vma's are
1155 * above the starting address given.
1156 */
1157 vma = find_vma(mm, addr);
1158
1159#ifdef CONFIG_MMU
1160 while (vma) {
1161 next = vma->vm_next;
1162
1163 /*
1164 * Check if the starting address would match, i.e. it's
1165 * a fragment created by mprotect() and/or munmap(), or it
1166 * otherwise it starts at this address with no hassles.
1167 */
1168 if ((vma->vm_ops == &shm_vm_ops) &&
1169 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1170
1171
1172 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1173 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1174 /*
1175 * We discovered the size of the shm segment, so
1176 * break out of here and fall through to the next
1177 * loop that uses the size information to stop
1178 * searching for matching vma's.
1179 */
1180 retval = 0;
1181 vma = next;
1182 break;
1183 }
1184 vma = next;
1185 }
1186
1187 /*
1188 * We need look no further than the maximum address a fragment
1189 * could possibly have landed at. Also cast things to loff_t to
1190 * prevent overflows and make comparisons vs. equal-width types.
1191 */
1192 size = PAGE_ALIGN(size);
1193 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1194 next = vma->vm_next;
1195
1196 /* finding a matching vma now does not alter retval */
1197 if ((vma->vm_ops == &shm_vm_ops) &&
1198 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1199
1200 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1201 vma = next;
1202 }
1203
1204#else /* CONFIG_MMU */
1205 /* under NOMMU conditions, the exact address to be destroyed must be
1206 * given */
1207 retval = -EINVAL;
1208 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1209 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1210 retval = 0;
1211 }
1212
1213#endif
1214
1215 up_write(&mm->mmap_sem);
1216 return retval;
1217}
1218
1219#ifdef CONFIG_PROC_FS
1220static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1221{
1222 struct shmid_kernel *shp = it;
1223 unsigned long rss = 0, swp = 0;
1224
1225 shm_add_rss_swap(shp, &rss, &swp);
1226
1227#if BITS_PER_LONG <= 32
1228#define SIZE_SPEC "%10lu"
1229#else
1230#define SIZE_SPEC "%21lu"
1231#endif
1232
1233 return seq_printf(s,
1234 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1235 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1236 SIZE_SPEC " " SIZE_SPEC "\n",
1237 shp->shm_perm.key,
1238 shp->shm_perm.id,
1239 shp->shm_perm.mode,
1240 shp->shm_segsz,
1241 shp->shm_cprid,
1242 shp->shm_lprid,
1243 shp->shm_nattch,
1244 shp->shm_perm.uid,
1245 shp->shm_perm.gid,
1246 shp->shm_perm.cuid,
1247 shp->shm_perm.cgid,
1248 shp->shm_atim,
1249 shp->shm_dtim,
1250 shp->shm_ctim,
1251 rss * PAGE_SIZE,
1252 swp * PAGE_SIZE);
1253}
1254#endif
1/*
2 * linux/ipc/shm.c
3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
4 * Many improvements/fixes by Bruno Haible.
5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
7 *
8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
15 *
16 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
18 *
19 * namespaces support
20 * OpenVZ, SWsoft Inc.
21 * Pavel Emelianov <xemul@openvz.org>
22 *
23 * Better ipc lock (kern_ipc_perm.lock) handling
24 * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
25 */
26
27#include <linux/slab.h>
28#include <linux/mm.h>
29#include <linux/hugetlb.h>
30#include <linux/shm.h>
31#include <linux/init.h>
32#include <linux/file.h>
33#include <linux/mman.h>
34#include <linux/shmem_fs.h>
35#include <linux/security.h>
36#include <linux/syscalls.h>
37#include <linux/audit.h>
38#include <linux/capability.h>
39#include <linux/ptrace.h>
40#include <linux/seq_file.h>
41#include <linux/rwsem.h>
42#include <linux/nsproxy.h>
43#include <linux/mount.h>
44#include <linux/ipc_namespace.h>
45
46#include <linux/uaccess.h>
47
48#include "util.h"
49
50struct shm_file_data {
51 int id;
52 struct ipc_namespace *ns;
53 struct file *file;
54 const struct vm_operations_struct *vm_ops;
55};
56
57#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
58
59static const struct file_operations shm_file_operations;
60static const struct vm_operations_struct shm_vm_ops;
61
62#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
63
64#define shm_unlock(shp) \
65 ipc_unlock(&(shp)->shm_perm)
66
67static int newseg(struct ipc_namespace *, struct ipc_params *);
68static void shm_open(struct vm_area_struct *vma);
69static void shm_close(struct vm_area_struct *vma);
70static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
71#ifdef CONFIG_PROC_FS
72static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
73#endif
74
75void shm_init_ns(struct ipc_namespace *ns)
76{
77 ns->shm_ctlmax = SHMMAX;
78 ns->shm_ctlall = SHMALL;
79 ns->shm_ctlmni = SHMMNI;
80 ns->shm_rmid_forced = 0;
81 ns->shm_tot = 0;
82 ipc_init_ids(&shm_ids(ns));
83}
84
85/*
86 * Called with shm_ids.rwsem (writer) and the shp structure locked.
87 * Only shm_ids.rwsem remains locked on exit.
88 */
89static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
90{
91 struct shmid_kernel *shp;
92 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
93
94 if (shp->shm_nattch) {
95 shp->shm_perm.mode |= SHM_DEST;
96 /* Do not find it any more */
97 shp->shm_perm.key = IPC_PRIVATE;
98 shm_unlock(shp);
99 } else
100 shm_destroy(ns, shp);
101}
102
103#ifdef CONFIG_IPC_NS
104void shm_exit_ns(struct ipc_namespace *ns)
105{
106 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
107 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
108}
109#endif
110
111static int __init ipc_ns_init(void)
112{
113 shm_init_ns(&init_ipc_ns);
114 return 0;
115}
116
117pure_initcall(ipc_ns_init);
118
119void __init shm_init(void)
120{
121 ipc_init_proc_interface("sysvipc/shm",
122#if BITS_PER_LONG <= 32
123 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
124#else
125 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
126#endif
127 IPC_SHM_IDS, sysvipc_shm_proc_show);
128}
129
130static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
131{
132 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
133
134 if (IS_ERR(ipcp))
135 return ERR_CAST(ipcp);
136
137 return container_of(ipcp, struct shmid_kernel, shm_perm);
138}
139
140static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
141{
142 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
143
144 if (IS_ERR(ipcp))
145 return ERR_CAST(ipcp);
146
147 return container_of(ipcp, struct shmid_kernel, shm_perm);
148}
149
150/*
151 * shm_lock_(check_) routines are called in the paths where the rwsem
152 * is not necessarily held.
153 */
154static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
155{
156 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
157
158 /*
159 * Callers of shm_lock() must validate the status of the returned ipc
160 * object pointer (as returned by ipc_lock()), and error out as
161 * appropriate.
162 */
163 if (IS_ERR(ipcp))
164 return (void *)ipcp;
165 return container_of(ipcp, struct shmid_kernel, shm_perm);
166}
167
168static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
169{
170 rcu_read_lock();
171 ipc_lock_object(&ipcp->shm_perm);
172}
173
174static void shm_rcu_free(struct rcu_head *head)
175{
176 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
177 struct shmid_kernel *shp = ipc_rcu_to_struct(p);
178
179 security_shm_free(shp);
180 ipc_rcu_free(head);
181}
182
183static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
184{
185 list_del(&s->shm_clist);
186 ipc_rmid(&shm_ids(ns), &s->shm_perm);
187}
188
189
190static int __shm_open(struct vm_area_struct *vma)
191{
192 struct file *file = vma->vm_file;
193 struct shm_file_data *sfd = shm_file_data(file);
194 struct shmid_kernel *shp;
195
196 shp = shm_lock(sfd->ns, sfd->id);
197
198 if (IS_ERR(shp))
199 return PTR_ERR(shp);
200
201 shp->shm_atim = get_seconds();
202 shp->shm_lprid = task_tgid_vnr(current);
203 shp->shm_nattch++;
204 shm_unlock(shp);
205 return 0;
206}
207
208/* This is called by fork, once for every shm attach. */
209static void shm_open(struct vm_area_struct *vma)
210{
211 int err = __shm_open(vma);
212 /*
213 * We raced in the idr lookup or with shm_destroy().
214 * Either way, the ID is busted.
215 */
216 WARN_ON_ONCE(err);
217}
218
219/*
220 * shm_destroy - free the struct shmid_kernel
221 *
222 * @ns: namespace
223 * @shp: struct to free
224 *
225 * It has to be called with shp and shm_ids.rwsem (writer) locked,
226 * but returns with shp unlocked and freed.
227 */
228static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
229{
230 struct file *shm_file;
231
232 shm_file = shp->shm_file;
233 shp->shm_file = NULL;
234 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
235 shm_rmid(ns, shp);
236 shm_unlock(shp);
237 if (!is_file_hugepages(shm_file))
238 shmem_lock(shm_file, 0, shp->mlock_user);
239 else if (shp->mlock_user)
240 user_shm_unlock(i_size_read(file_inode(shm_file)),
241 shp->mlock_user);
242 fput(shm_file);
243 ipc_rcu_putref(shp, shm_rcu_free);
244}
245
246/*
247 * shm_may_destroy - identifies whether shm segment should be destroyed now
248 *
249 * Returns true if and only if there are no active users of the segment and
250 * one of the following is true:
251 *
252 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
253 *
254 * 2) sysctl kernel.shm_rmid_forced is set to 1.
255 */
256static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
257{
258 return (shp->shm_nattch == 0) &&
259 (ns->shm_rmid_forced ||
260 (shp->shm_perm.mode & SHM_DEST));
261}
262
263/*
264 * remove the attach descriptor vma.
265 * free memory for segment if it is marked destroyed.
266 * The descriptor has already been removed from the current->mm->mmap list
267 * and will later be kfree()d.
268 */
269static void shm_close(struct vm_area_struct *vma)
270{
271 struct file *file = vma->vm_file;
272 struct shm_file_data *sfd = shm_file_data(file);
273 struct shmid_kernel *shp;
274 struct ipc_namespace *ns = sfd->ns;
275
276 down_write(&shm_ids(ns).rwsem);
277 /* remove from the list of attaches of the shm segment */
278 shp = shm_lock(ns, sfd->id);
279
280 /*
281 * We raced in the idr lookup or with shm_destroy().
282 * Either way, the ID is busted.
283 */
284 if (WARN_ON_ONCE(IS_ERR(shp)))
285 goto done; /* no-op */
286
287 shp->shm_lprid = task_tgid_vnr(current);
288 shp->shm_dtim = get_seconds();
289 shp->shm_nattch--;
290 if (shm_may_destroy(ns, shp))
291 shm_destroy(ns, shp);
292 else
293 shm_unlock(shp);
294done:
295 up_write(&shm_ids(ns).rwsem);
296}
297
298/* Called with ns->shm_ids(ns).rwsem locked */
299static int shm_try_destroy_orphaned(int id, void *p, void *data)
300{
301 struct ipc_namespace *ns = data;
302 struct kern_ipc_perm *ipcp = p;
303 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
304
305 /*
306 * We want to destroy segments without users and with already
307 * exit'ed originating process.
308 *
309 * As shp->* are changed under rwsem, it's safe to skip shp locking.
310 */
311 if (shp->shm_creator != NULL)
312 return 0;
313
314 if (shm_may_destroy(ns, shp)) {
315 shm_lock_by_ptr(shp);
316 shm_destroy(ns, shp);
317 }
318 return 0;
319}
320
321void shm_destroy_orphaned(struct ipc_namespace *ns)
322{
323 down_write(&shm_ids(ns).rwsem);
324 if (shm_ids(ns).in_use)
325 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
326 up_write(&shm_ids(ns).rwsem);
327}
328
329/* Locking assumes this will only be called with task == current */
330void exit_shm(struct task_struct *task)
331{
332 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
333 struct shmid_kernel *shp, *n;
334
335 if (list_empty(&task->sysvshm.shm_clist))
336 return;
337
338 /*
339 * If kernel.shm_rmid_forced is not set then only keep track of
340 * which shmids are orphaned, so that a later set of the sysctl
341 * can clean them up.
342 */
343 if (!ns->shm_rmid_forced) {
344 down_read(&shm_ids(ns).rwsem);
345 list_for_each_entry(shp, &task->sysvshm.shm_clist, shm_clist)
346 shp->shm_creator = NULL;
347 /*
348 * Only under read lock but we are only called on current
349 * so no entry on the list will be shared.
350 */
351 list_del(&task->sysvshm.shm_clist);
352 up_read(&shm_ids(ns).rwsem);
353 return;
354 }
355
356 /*
357 * Destroy all already created segments, that were not yet mapped,
358 * and mark any mapped as orphan to cover the sysctl toggling.
359 * Destroy is skipped if shm_may_destroy() returns false.
360 */
361 down_write(&shm_ids(ns).rwsem);
362 list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) {
363 shp->shm_creator = NULL;
364
365 if (shm_may_destroy(ns, shp)) {
366 shm_lock_by_ptr(shp);
367 shm_destroy(ns, shp);
368 }
369 }
370
371 /* Remove the list head from any segments still attached. */
372 list_del(&task->sysvshm.shm_clist);
373 up_write(&shm_ids(ns).rwsem);
374}
375
376static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
377{
378 struct file *file = vma->vm_file;
379 struct shm_file_data *sfd = shm_file_data(file);
380
381 return sfd->vm_ops->fault(vma, vmf);
382}
383
384#ifdef CONFIG_NUMA
385static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
386{
387 struct file *file = vma->vm_file;
388 struct shm_file_data *sfd = shm_file_data(file);
389 int err = 0;
390 if (sfd->vm_ops->set_policy)
391 err = sfd->vm_ops->set_policy(vma, new);
392 return err;
393}
394
395static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
396 unsigned long addr)
397{
398 struct file *file = vma->vm_file;
399 struct shm_file_data *sfd = shm_file_data(file);
400 struct mempolicy *pol = NULL;
401
402 if (sfd->vm_ops->get_policy)
403 pol = sfd->vm_ops->get_policy(vma, addr);
404 else if (vma->vm_policy)
405 pol = vma->vm_policy;
406
407 return pol;
408}
409#endif
410
411static int shm_mmap(struct file *file, struct vm_area_struct *vma)
412{
413 struct shm_file_data *sfd = shm_file_data(file);
414 int ret;
415
416 /*
417 * In case of remap_file_pages() emulation, the file can represent
418 * removed IPC ID: propogate shm_lock() error to caller.
419 */
420 ret =__shm_open(vma);
421 if (ret)
422 return ret;
423
424 ret = sfd->file->f_op->mmap(sfd->file, vma);
425 if (ret) {
426 shm_close(vma);
427 return ret;
428 }
429 sfd->vm_ops = vma->vm_ops;
430#ifdef CONFIG_MMU
431 WARN_ON(!sfd->vm_ops->fault);
432#endif
433 vma->vm_ops = &shm_vm_ops;
434 return 0;
435}
436
437static int shm_release(struct inode *ino, struct file *file)
438{
439 struct shm_file_data *sfd = shm_file_data(file);
440
441 put_ipc_ns(sfd->ns);
442 shm_file_data(file) = NULL;
443 kfree(sfd);
444 return 0;
445}
446
447static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
448{
449 struct shm_file_data *sfd = shm_file_data(file);
450
451 if (!sfd->file->f_op->fsync)
452 return -EINVAL;
453 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
454}
455
456static long shm_fallocate(struct file *file, int mode, loff_t offset,
457 loff_t len)
458{
459 struct shm_file_data *sfd = shm_file_data(file);
460
461 if (!sfd->file->f_op->fallocate)
462 return -EOPNOTSUPP;
463 return sfd->file->f_op->fallocate(file, mode, offset, len);
464}
465
466static unsigned long shm_get_unmapped_area(struct file *file,
467 unsigned long addr, unsigned long len, unsigned long pgoff,
468 unsigned long flags)
469{
470 struct shm_file_data *sfd = shm_file_data(file);
471 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
472 pgoff, flags);
473}
474
475static const struct file_operations shm_file_operations = {
476 .mmap = shm_mmap,
477 .fsync = shm_fsync,
478 .release = shm_release,
479#ifndef CONFIG_MMU
480 .get_unmapped_area = shm_get_unmapped_area,
481#endif
482 .llseek = noop_llseek,
483 .fallocate = shm_fallocate,
484};
485
486static const struct file_operations shm_file_operations_huge = {
487 .mmap = shm_mmap,
488 .fsync = shm_fsync,
489 .release = shm_release,
490 .get_unmapped_area = shm_get_unmapped_area,
491 .llseek = noop_llseek,
492 .fallocate = shm_fallocate,
493};
494
495bool is_file_shm_hugepages(struct file *file)
496{
497 return file->f_op == &shm_file_operations_huge;
498}
499
500static const struct vm_operations_struct shm_vm_ops = {
501 .open = shm_open, /* callback for a new vm-area open */
502 .close = shm_close, /* callback for when the vm-area is released */
503 .fault = shm_fault,
504#if defined(CONFIG_NUMA)
505 .set_policy = shm_set_policy,
506 .get_policy = shm_get_policy,
507#endif
508};
509
510/**
511 * newseg - Create a new shared memory segment
512 * @ns: namespace
513 * @params: ptr to the structure that contains key, size and shmflg
514 *
515 * Called with shm_ids.rwsem held as a writer.
516 */
517static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
518{
519 key_t key = params->key;
520 int shmflg = params->flg;
521 size_t size = params->u.size;
522 int error;
523 struct shmid_kernel *shp;
524 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
525 struct file *file;
526 char name[13];
527 int id;
528 vm_flags_t acctflag = 0;
529
530 if (size < SHMMIN || size > ns->shm_ctlmax)
531 return -EINVAL;
532
533 if (numpages << PAGE_SHIFT < size)
534 return -ENOSPC;
535
536 if (ns->shm_tot + numpages < ns->shm_tot ||
537 ns->shm_tot + numpages > ns->shm_ctlall)
538 return -ENOSPC;
539
540 shp = ipc_rcu_alloc(sizeof(*shp));
541 if (!shp)
542 return -ENOMEM;
543
544 shp->shm_perm.key = key;
545 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
546 shp->mlock_user = NULL;
547
548 shp->shm_perm.security = NULL;
549 error = security_shm_alloc(shp);
550 if (error) {
551 ipc_rcu_putref(shp, ipc_rcu_free);
552 return error;
553 }
554
555 sprintf(name, "SYSV%08x", key);
556 if (shmflg & SHM_HUGETLB) {
557 struct hstate *hs;
558 size_t hugesize;
559
560 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
561 if (!hs) {
562 error = -EINVAL;
563 goto no_file;
564 }
565 hugesize = ALIGN(size, huge_page_size(hs));
566
567 /* hugetlb_file_setup applies strict accounting */
568 if (shmflg & SHM_NORESERVE)
569 acctflag = VM_NORESERVE;
570 file = hugetlb_file_setup(name, hugesize, acctflag,
571 &shp->mlock_user, HUGETLB_SHMFS_INODE,
572 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
573 } else {
574 /*
575 * Do not allow no accounting for OVERCOMMIT_NEVER, even
576 * if it's asked for.
577 */
578 if ((shmflg & SHM_NORESERVE) &&
579 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
580 acctflag = VM_NORESERVE;
581 file = shmem_kernel_file_setup(name, size, acctflag);
582 }
583 error = PTR_ERR(file);
584 if (IS_ERR(file))
585 goto no_file;
586
587 shp->shm_cprid = task_tgid_vnr(current);
588 shp->shm_lprid = 0;
589 shp->shm_atim = shp->shm_dtim = 0;
590 shp->shm_ctim = get_seconds();
591 shp->shm_segsz = size;
592 shp->shm_nattch = 0;
593 shp->shm_file = file;
594 shp->shm_creator = current;
595
596 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
597 if (id < 0) {
598 error = id;
599 goto no_id;
600 }
601
602 list_add(&shp->shm_clist, ¤t->sysvshm.shm_clist);
603
604 /*
605 * shmid gets reported as "inode#" in /proc/pid/maps.
606 * proc-ps tools use this. Changing this will break them.
607 */
608 file_inode(file)->i_ino = shp->shm_perm.id;
609
610 ns->shm_tot += numpages;
611 error = shp->shm_perm.id;
612
613 ipc_unlock_object(&shp->shm_perm);
614 rcu_read_unlock();
615 return error;
616
617no_id:
618 if (is_file_hugepages(file) && shp->mlock_user)
619 user_shm_unlock(size, shp->mlock_user);
620 fput(file);
621no_file:
622 ipc_rcu_putref(shp, shm_rcu_free);
623 return error;
624}
625
626/*
627 * Called with shm_ids.rwsem and ipcp locked.
628 */
629static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
630{
631 struct shmid_kernel *shp;
632
633 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
634 return security_shm_associate(shp, shmflg);
635}
636
637/*
638 * Called with shm_ids.rwsem and ipcp locked.
639 */
640static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
641 struct ipc_params *params)
642{
643 struct shmid_kernel *shp;
644
645 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
646 if (shp->shm_segsz < params->u.size)
647 return -EINVAL;
648
649 return 0;
650}
651
652SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
653{
654 struct ipc_namespace *ns;
655 static const struct ipc_ops shm_ops = {
656 .getnew = newseg,
657 .associate = shm_security,
658 .more_checks = shm_more_checks,
659 };
660 struct ipc_params shm_params;
661
662 ns = current->nsproxy->ipc_ns;
663
664 shm_params.key = key;
665 shm_params.flg = shmflg;
666 shm_params.u.size = size;
667
668 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
669}
670
671static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
672{
673 switch (version) {
674 case IPC_64:
675 return copy_to_user(buf, in, sizeof(*in));
676 case IPC_OLD:
677 {
678 struct shmid_ds out;
679
680 memset(&out, 0, sizeof(out));
681 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
682 out.shm_segsz = in->shm_segsz;
683 out.shm_atime = in->shm_atime;
684 out.shm_dtime = in->shm_dtime;
685 out.shm_ctime = in->shm_ctime;
686 out.shm_cpid = in->shm_cpid;
687 out.shm_lpid = in->shm_lpid;
688 out.shm_nattch = in->shm_nattch;
689
690 return copy_to_user(buf, &out, sizeof(out));
691 }
692 default:
693 return -EINVAL;
694 }
695}
696
697static inline unsigned long
698copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
699{
700 switch (version) {
701 case IPC_64:
702 if (copy_from_user(out, buf, sizeof(*out)))
703 return -EFAULT;
704 return 0;
705 case IPC_OLD:
706 {
707 struct shmid_ds tbuf_old;
708
709 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
710 return -EFAULT;
711
712 out->shm_perm.uid = tbuf_old.shm_perm.uid;
713 out->shm_perm.gid = tbuf_old.shm_perm.gid;
714 out->shm_perm.mode = tbuf_old.shm_perm.mode;
715
716 return 0;
717 }
718 default:
719 return -EINVAL;
720 }
721}
722
723static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
724{
725 switch (version) {
726 case IPC_64:
727 return copy_to_user(buf, in, sizeof(*in));
728 case IPC_OLD:
729 {
730 struct shminfo out;
731
732 if (in->shmmax > INT_MAX)
733 out.shmmax = INT_MAX;
734 else
735 out.shmmax = (int)in->shmmax;
736
737 out.shmmin = in->shmmin;
738 out.shmmni = in->shmmni;
739 out.shmseg = in->shmseg;
740 out.shmall = in->shmall;
741
742 return copy_to_user(buf, &out, sizeof(out));
743 }
744 default:
745 return -EINVAL;
746 }
747}
748
749/*
750 * Calculate and add used RSS and swap pages of a shm.
751 * Called with shm_ids.rwsem held as a reader
752 */
753static void shm_add_rss_swap(struct shmid_kernel *shp,
754 unsigned long *rss_add, unsigned long *swp_add)
755{
756 struct inode *inode;
757
758 inode = file_inode(shp->shm_file);
759
760 if (is_file_hugepages(shp->shm_file)) {
761 struct address_space *mapping = inode->i_mapping;
762 struct hstate *h = hstate_file(shp->shm_file);
763 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
764 } else {
765#ifdef CONFIG_SHMEM
766 struct shmem_inode_info *info = SHMEM_I(inode);
767 spin_lock(&info->lock);
768 *rss_add += inode->i_mapping->nrpages;
769 *swp_add += info->swapped;
770 spin_unlock(&info->lock);
771#else
772 *rss_add += inode->i_mapping->nrpages;
773#endif
774 }
775}
776
777/*
778 * Called with shm_ids.rwsem held as a reader
779 */
780static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
781 unsigned long *swp)
782{
783 int next_id;
784 int total, in_use;
785
786 *rss = 0;
787 *swp = 0;
788
789 in_use = shm_ids(ns).in_use;
790
791 for (total = 0, next_id = 0; total < in_use; next_id++) {
792 struct kern_ipc_perm *ipc;
793 struct shmid_kernel *shp;
794
795 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
796 if (ipc == NULL)
797 continue;
798 shp = container_of(ipc, struct shmid_kernel, shm_perm);
799
800 shm_add_rss_swap(shp, rss, swp);
801
802 total++;
803 }
804}
805
806/*
807 * This function handles some shmctl commands which require the rwsem
808 * to be held in write mode.
809 * NOTE: no locks must be held, the rwsem is taken inside this function.
810 */
811static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
812 struct shmid_ds __user *buf, int version)
813{
814 struct kern_ipc_perm *ipcp;
815 struct shmid64_ds shmid64;
816 struct shmid_kernel *shp;
817 int err;
818
819 if (cmd == IPC_SET) {
820 if (copy_shmid_from_user(&shmid64, buf, version))
821 return -EFAULT;
822 }
823
824 down_write(&shm_ids(ns).rwsem);
825 rcu_read_lock();
826
827 ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
828 &shmid64.shm_perm, 0);
829 if (IS_ERR(ipcp)) {
830 err = PTR_ERR(ipcp);
831 goto out_unlock1;
832 }
833
834 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
835
836 err = security_shm_shmctl(shp, cmd);
837 if (err)
838 goto out_unlock1;
839
840 switch (cmd) {
841 case IPC_RMID:
842 ipc_lock_object(&shp->shm_perm);
843 /* do_shm_rmid unlocks the ipc object and rcu */
844 do_shm_rmid(ns, ipcp);
845 goto out_up;
846 case IPC_SET:
847 ipc_lock_object(&shp->shm_perm);
848 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
849 if (err)
850 goto out_unlock0;
851 shp->shm_ctim = get_seconds();
852 break;
853 default:
854 err = -EINVAL;
855 goto out_unlock1;
856 }
857
858out_unlock0:
859 ipc_unlock_object(&shp->shm_perm);
860out_unlock1:
861 rcu_read_unlock();
862out_up:
863 up_write(&shm_ids(ns).rwsem);
864 return err;
865}
866
867static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
868 int cmd, int version, void __user *buf)
869{
870 int err;
871 struct shmid_kernel *shp;
872
873 /* preliminary security checks for *_INFO */
874 if (cmd == IPC_INFO || cmd == SHM_INFO) {
875 err = security_shm_shmctl(NULL, cmd);
876 if (err)
877 return err;
878 }
879
880 switch (cmd) {
881 case IPC_INFO:
882 {
883 struct shminfo64 shminfo;
884
885 memset(&shminfo, 0, sizeof(shminfo));
886 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
887 shminfo.shmmax = ns->shm_ctlmax;
888 shminfo.shmall = ns->shm_ctlall;
889
890 shminfo.shmmin = SHMMIN;
891 if (copy_shminfo_to_user(buf, &shminfo, version))
892 return -EFAULT;
893
894 down_read(&shm_ids(ns).rwsem);
895 err = ipc_get_maxid(&shm_ids(ns));
896 up_read(&shm_ids(ns).rwsem);
897
898 if (err < 0)
899 err = 0;
900 goto out;
901 }
902 case SHM_INFO:
903 {
904 struct shm_info shm_info;
905
906 memset(&shm_info, 0, sizeof(shm_info));
907 down_read(&shm_ids(ns).rwsem);
908 shm_info.used_ids = shm_ids(ns).in_use;
909 shm_get_stat(ns, &shm_info.shm_rss, &shm_info.shm_swp);
910 shm_info.shm_tot = ns->shm_tot;
911 shm_info.swap_attempts = 0;
912 shm_info.swap_successes = 0;
913 err = ipc_get_maxid(&shm_ids(ns));
914 up_read(&shm_ids(ns).rwsem);
915 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
916 err = -EFAULT;
917 goto out;
918 }
919
920 err = err < 0 ? 0 : err;
921 goto out;
922 }
923 case SHM_STAT:
924 case IPC_STAT:
925 {
926 struct shmid64_ds tbuf;
927 int result;
928
929 rcu_read_lock();
930 if (cmd == SHM_STAT) {
931 shp = shm_obtain_object(ns, shmid);
932 if (IS_ERR(shp)) {
933 err = PTR_ERR(shp);
934 goto out_unlock;
935 }
936 result = shp->shm_perm.id;
937 } else {
938 shp = shm_obtain_object_check(ns, shmid);
939 if (IS_ERR(shp)) {
940 err = PTR_ERR(shp);
941 goto out_unlock;
942 }
943 result = 0;
944 }
945
946 err = -EACCES;
947 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
948 goto out_unlock;
949
950 err = security_shm_shmctl(shp, cmd);
951 if (err)
952 goto out_unlock;
953
954 memset(&tbuf, 0, sizeof(tbuf));
955 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
956 tbuf.shm_segsz = shp->shm_segsz;
957 tbuf.shm_atime = shp->shm_atim;
958 tbuf.shm_dtime = shp->shm_dtim;
959 tbuf.shm_ctime = shp->shm_ctim;
960 tbuf.shm_cpid = shp->shm_cprid;
961 tbuf.shm_lpid = shp->shm_lprid;
962 tbuf.shm_nattch = shp->shm_nattch;
963 rcu_read_unlock();
964
965 if (copy_shmid_to_user(buf, &tbuf, version))
966 err = -EFAULT;
967 else
968 err = result;
969 goto out;
970 }
971 default:
972 return -EINVAL;
973 }
974
975out_unlock:
976 rcu_read_unlock();
977out:
978 return err;
979}
980
981SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
982{
983 struct shmid_kernel *shp;
984 int err, version;
985 struct ipc_namespace *ns;
986
987 if (cmd < 0 || shmid < 0)
988 return -EINVAL;
989
990 version = ipc_parse_version(&cmd);
991 ns = current->nsproxy->ipc_ns;
992
993 switch (cmd) {
994 case IPC_INFO:
995 case SHM_INFO:
996 case SHM_STAT:
997 case IPC_STAT:
998 return shmctl_nolock(ns, shmid, cmd, version, buf);
999 case IPC_RMID:
1000 case IPC_SET:
1001 return shmctl_down(ns, shmid, cmd, buf, version);
1002 case SHM_LOCK:
1003 case SHM_UNLOCK:
1004 {
1005 struct file *shm_file;
1006
1007 rcu_read_lock();
1008 shp = shm_obtain_object_check(ns, shmid);
1009 if (IS_ERR(shp)) {
1010 err = PTR_ERR(shp);
1011 goto out_unlock1;
1012 }
1013
1014 audit_ipc_obj(&(shp->shm_perm));
1015 err = security_shm_shmctl(shp, cmd);
1016 if (err)
1017 goto out_unlock1;
1018
1019 ipc_lock_object(&shp->shm_perm);
1020
1021 /* check if shm_destroy() is tearing down shp */
1022 if (!ipc_valid_object(&shp->shm_perm)) {
1023 err = -EIDRM;
1024 goto out_unlock0;
1025 }
1026
1027 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
1028 kuid_t euid = current_euid();
1029 if (!uid_eq(euid, shp->shm_perm.uid) &&
1030 !uid_eq(euid, shp->shm_perm.cuid)) {
1031 err = -EPERM;
1032 goto out_unlock0;
1033 }
1034 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1035 err = -EPERM;
1036 goto out_unlock0;
1037 }
1038 }
1039
1040 shm_file = shp->shm_file;
1041 if (is_file_hugepages(shm_file))
1042 goto out_unlock0;
1043
1044 if (cmd == SHM_LOCK) {
1045 struct user_struct *user = current_user();
1046 err = shmem_lock(shm_file, 1, user);
1047 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1048 shp->shm_perm.mode |= SHM_LOCKED;
1049 shp->mlock_user = user;
1050 }
1051 goto out_unlock0;
1052 }
1053
1054 /* SHM_UNLOCK */
1055 if (!(shp->shm_perm.mode & SHM_LOCKED))
1056 goto out_unlock0;
1057 shmem_lock(shm_file, 0, shp->mlock_user);
1058 shp->shm_perm.mode &= ~SHM_LOCKED;
1059 shp->mlock_user = NULL;
1060 get_file(shm_file);
1061 ipc_unlock_object(&shp->shm_perm);
1062 rcu_read_unlock();
1063 shmem_unlock_mapping(shm_file->f_mapping);
1064
1065 fput(shm_file);
1066 return err;
1067 }
1068 default:
1069 return -EINVAL;
1070 }
1071
1072out_unlock0:
1073 ipc_unlock_object(&shp->shm_perm);
1074out_unlock1:
1075 rcu_read_unlock();
1076 return err;
1077}
1078
1079/*
1080 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1081 *
1082 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1083 * "raddr" thing points to kernel space, and there has to be a wrapper around
1084 * this.
1085 */
1086long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
1087 unsigned long shmlba)
1088{
1089 struct shmid_kernel *shp;
1090 unsigned long addr;
1091 unsigned long size;
1092 struct file *file;
1093 int err;
1094 unsigned long flags;
1095 unsigned long prot;
1096 int acc_mode;
1097 struct ipc_namespace *ns;
1098 struct shm_file_data *sfd;
1099 struct path path;
1100 fmode_t f_mode;
1101 unsigned long populate = 0;
1102
1103 err = -EINVAL;
1104 if (shmid < 0)
1105 goto out;
1106 else if ((addr = (ulong)shmaddr)) {
1107 if (addr & (shmlba - 1)) {
1108 if (shmflg & SHM_RND)
1109 addr &= ~(shmlba - 1); /* round down */
1110 else
1111#ifndef __ARCH_FORCE_SHMLBA
1112 if (addr & ~PAGE_MASK)
1113#endif
1114 goto out;
1115 }
1116 flags = MAP_SHARED | MAP_FIXED;
1117 } else {
1118 if ((shmflg & SHM_REMAP))
1119 goto out;
1120
1121 flags = MAP_SHARED;
1122 }
1123
1124 if (shmflg & SHM_RDONLY) {
1125 prot = PROT_READ;
1126 acc_mode = S_IRUGO;
1127 f_mode = FMODE_READ;
1128 } else {
1129 prot = PROT_READ | PROT_WRITE;
1130 acc_mode = S_IRUGO | S_IWUGO;
1131 f_mode = FMODE_READ | FMODE_WRITE;
1132 }
1133 if (shmflg & SHM_EXEC) {
1134 prot |= PROT_EXEC;
1135 acc_mode |= S_IXUGO;
1136 }
1137
1138 /*
1139 * We cannot rely on the fs check since SYSV IPC does have an
1140 * additional creator id...
1141 */
1142 ns = current->nsproxy->ipc_ns;
1143 rcu_read_lock();
1144 shp = shm_obtain_object_check(ns, shmid);
1145 if (IS_ERR(shp)) {
1146 err = PTR_ERR(shp);
1147 goto out_unlock;
1148 }
1149
1150 err = -EACCES;
1151 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1152 goto out_unlock;
1153
1154 err = security_shm_shmat(shp, shmaddr, shmflg);
1155 if (err)
1156 goto out_unlock;
1157
1158 ipc_lock_object(&shp->shm_perm);
1159
1160 /* check if shm_destroy() is tearing down shp */
1161 if (!ipc_valid_object(&shp->shm_perm)) {
1162 ipc_unlock_object(&shp->shm_perm);
1163 err = -EIDRM;
1164 goto out_unlock;
1165 }
1166
1167 path = shp->shm_file->f_path;
1168 path_get(&path);
1169 shp->shm_nattch++;
1170 size = i_size_read(d_inode(path.dentry));
1171 ipc_unlock_object(&shp->shm_perm);
1172 rcu_read_unlock();
1173
1174 err = -ENOMEM;
1175 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1176 if (!sfd) {
1177 path_put(&path);
1178 goto out_nattch;
1179 }
1180
1181 file = alloc_file(&path, f_mode,
1182 is_file_hugepages(shp->shm_file) ?
1183 &shm_file_operations_huge :
1184 &shm_file_operations);
1185 err = PTR_ERR(file);
1186 if (IS_ERR(file)) {
1187 kfree(sfd);
1188 path_put(&path);
1189 goto out_nattch;
1190 }
1191
1192 file->private_data = sfd;
1193 file->f_mapping = shp->shm_file->f_mapping;
1194 sfd->id = shp->shm_perm.id;
1195 sfd->ns = get_ipc_ns(ns);
1196 sfd->file = shp->shm_file;
1197 sfd->vm_ops = NULL;
1198
1199 err = security_mmap_file(file, prot, flags);
1200 if (err)
1201 goto out_fput;
1202
1203 down_write(¤t->mm->mmap_sem);
1204 if (addr && !(shmflg & SHM_REMAP)) {
1205 err = -EINVAL;
1206 if (addr + size < addr)
1207 goto invalid;
1208
1209 if (find_vma_intersection(current->mm, addr, addr + size))
1210 goto invalid;
1211 }
1212
1213 addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1214 *raddr = addr;
1215 err = 0;
1216 if (IS_ERR_VALUE(addr))
1217 err = (long)addr;
1218invalid:
1219 up_write(¤t->mm->mmap_sem);
1220 if (populate)
1221 mm_populate(addr, populate);
1222
1223out_fput:
1224 fput(file);
1225
1226out_nattch:
1227 down_write(&shm_ids(ns).rwsem);
1228 shp = shm_lock(ns, shmid);
1229 shp->shm_nattch--;
1230 if (shm_may_destroy(ns, shp))
1231 shm_destroy(ns, shp);
1232 else
1233 shm_unlock(shp);
1234 up_write(&shm_ids(ns).rwsem);
1235 return err;
1236
1237out_unlock:
1238 rcu_read_unlock();
1239out:
1240 return err;
1241}
1242
1243SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1244{
1245 unsigned long ret;
1246 long err;
1247
1248 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1249 if (err)
1250 return err;
1251 force_successful_syscall_return();
1252 return (long)ret;
1253}
1254
1255/*
1256 * detach and kill segment if marked destroyed.
1257 * The work is done in shm_close.
1258 */
1259SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1260{
1261 struct mm_struct *mm = current->mm;
1262 struct vm_area_struct *vma;
1263 unsigned long addr = (unsigned long)shmaddr;
1264 int retval = -EINVAL;
1265#ifdef CONFIG_MMU
1266 loff_t size = 0;
1267 struct file *file;
1268 struct vm_area_struct *next;
1269#endif
1270
1271 if (addr & ~PAGE_MASK)
1272 return retval;
1273
1274 down_write(&mm->mmap_sem);
1275
1276 /*
1277 * This function tries to be smart and unmap shm segments that
1278 * were modified by partial mlock or munmap calls:
1279 * - It first determines the size of the shm segment that should be
1280 * unmapped: It searches for a vma that is backed by shm and that
1281 * started at address shmaddr. It records it's size and then unmaps
1282 * it.
1283 * - Then it unmaps all shm vmas that started at shmaddr and that
1284 * are within the initially determined size and that are from the
1285 * same shm segment from which we determined the size.
1286 * Errors from do_munmap are ignored: the function only fails if
1287 * it's called with invalid parameters or if it's called to unmap
1288 * a part of a vma. Both calls in this function are for full vmas,
1289 * the parameters are directly copied from the vma itself and always
1290 * valid - therefore do_munmap cannot fail. (famous last words?)
1291 */
1292 /*
1293 * If it had been mremap()'d, the starting address would not
1294 * match the usual checks anyway. So assume all vma's are
1295 * above the starting address given.
1296 */
1297 vma = find_vma(mm, addr);
1298
1299#ifdef CONFIG_MMU
1300 while (vma) {
1301 next = vma->vm_next;
1302
1303 /*
1304 * Check if the starting address would match, i.e. it's
1305 * a fragment created by mprotect() and/or munmap(), or it
1306 * otherwise it starts at this address with no hassles.
1307 */
1308 if ((vma->vm_ops == &shm_vm_ops) &&
1309 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1310
1311 /*
1312 * Record the file of the shm segment being
1313 * unmapped. With mremap(), someone could place
1314 * page from another segment but with equal offsets
1315 * in the range we are unmapping.
1316 */
1317 file = vma->vm_file;
1318 size = i_size_read(file_inode(vma->vm_file));
1319 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1320 /*
1321 * We discovered the size of the shm segment, so
1322 * break out of here and fall through to the next
1323 * loop that uses the size information to stop
1324 * searching for matching vma's.
1325 */
1326 retval = 0;
1327 vma = next;
1328 break;
1329 }
1330 vma = next;
1331 }
1332
1333 /*
1334 * We need look no further than the maximum address a fragment
1335 * could possibly have landed at. Also cast things to loff_t to
1336 * prevent overflows and make comparisons vs. equal-width types.
1337 */
1338 size = PAGE_ALIGN(size);
1339 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1340 next = vma->vm_next;
1341
1342 /* finding a matching vma now does not alter retval */
1343 if ((vma->vm_ops == &shm_vm_ops) &&
1344 ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1345 (vma->vm_file == file))
1346 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1347 vma = next;
1348 }
1349
1350#else /* CONFIG_MMU */
1351 /* under NOMMU conditions, the exact address to be destroyed must be
1352 * given */
1353 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1354 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1355 retval = 0;
1356 }
1357
1358#endif
1359
1360 up_write(&mm->mmap_sem);
1361 return retval;
1362}
1363
1364#ifdef CONFIG_PROC_FS
1365static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1366{
1367 struct user_namespace *user_ns = seq_user_ns(s);
1368 struct shmid_kernel *shp = it;
1369 unsigned long rss = 0, swp = 0;
1370
1371 shm_add_rss_swap(shp, &rss, &swp);
1372
1373#if BITS_PER_LONG <= 32
1374#define SIZE_SPEC "%10lu"
1375#else
1376#define SIZE_SPEC "%21lu"
1377#endif
1378
1379 seq_printf(s,
1380 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1381 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1382 SIZE_SPEC " " SIZE_SPEC "\n",
1383 shp->shm_perm.key,
1384 shp->shm_perm.id,
1385 shp->shm_perm.mode,
1386 shp->shm_segsz,
1387 shp->shm_cprid,
1388 shp->shm_lprid,
1389 shp->shm_nattch,
1390 from_kuid_munged(user_ns, shp->shm_perm.uid),
1391 from_kgid_munged(user_ns, shp->shm_perm.gid),
1392 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1393 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1394 shp->shm_atim,
1395 shp->shm_dtim,
1396 shp->shm_ctim,
1397 rss * PAGE_SIZE,
1398 swp * PAGE_SIZE);
1399
1400 return 0;
1401}
1402#endif