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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 unsigned long shm_get_unmapped_area(struct file *file,
397 unsigned long addr, unsigned long len, unsigned long pgoff,
398 unsigned long flags)
399{
400 struct shm_file_data *sfd = shm_file_data(file);
401 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
402 pgoff, flags);
403}
404
405static const struct file_operations shm_file_operations = {
406 .mmap = shm_mmap,
407 .fsync = shm_fsync,
408 .release = shm_release,
409#ifndef CONFIG_MMU
410 .get_unmapped_area = shm_get_unmapped_area,
411#endif
412 .llseek = noop_llseek,
413};
414
415static const struct file_operations shm_file_operations_huge = {
416 .mmap = shm_mmap,
417 .fsync = shm_fsync,
418 .release = shm_release,
419 .get_unmapped_area = shm_get_unmapped_area,
420 .llseek = noop_llseek,
421};
422
423int is_file_shm_hugepages(struct file *file)
424{
425 return file->f_op == &shm_file_operations_huge;
426}
427
428static const struct vm_operations_struct shm_vm_ops = {
429 .open = shm_open, /* callback for a new vm-area open */
430 .close = shm_close, /* callback for when the vm-area is released */
431 .fault = shm_fault,
432#if defined(CONFIG_NUMA)
433 .set_policy = shm_set_policy,
434 .get_policy = shm_get_policy,
435#endif
436};
437
438/**
439 * newseg - Create a new shared memory segment
440 * @ns: namespace
441 * @params: ptr to the structure that contains key, size and shmflg
442 *
443 * Called with shm_ids.rw_mutex held as a writer.
444 */
445
446static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
447{
448 key_t key = params->key;
449 int shmflg = params->flg;
450 size_t size = params->u.size;
451 int error;
452 struct shmid_kernel *shp;
453 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
454 struct file * file;
455 char name[13];
456 int id;
457 vm_flags_t acctflag = 0;
458
459 if (size < SHMMIN || size > ns->shm_ctlmax)
460 return -EINVAL;
461
462 if (ns->shm_tot + numpages > ns->shm_ctlall)
463 return -ENOSPC;
464
465 shp = ipc_rcu_alloc(sizeof(*shp));
466 if (!shp)
467 return -ENOMEM;
468
469 shp->shm_perm.key = key;
470 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
471 shp->mlock_user = NULL;
472
473 shp->shm_perm.security = NULL;
474 error = security_shm_alloc(shp);
475 if (error) {
476 ipc_rcu_putref(shp);
477 return error;
478 }
479
480 sprintf (name, "SYSV%08x", key);
481 if (shmflg & SHM_HUGETLB) {
482 /* hugetlb_file_setup applies strict accounting */
483 if (shmflg & SHM_NORESERVE)
484 acctflag = VM_NORESERVE;
485 file = hugetlb_file_setup(name, size, acctflag,
486 &shp->mlock_user, HUGETLB_SHMFS_INODE);
487 } else {
488 /*
489 * Do not allow no accounting for OVERCOMMIT_NEVER, even
490 * if it's asked for.
491 */
492 if ((shmflg & SHM_NORESERVE) &&
493 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
494 acctflag = VM_NORESERVE;
495 file = shmem_file_setup(name, size, acctflag);
496 }
497 error = PTR_ERR(file);
498 if (IS_ERR(file))
499 goto no_file;
500
501 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
502 if (id < 0) {
503 error = id;
504 goto no_id;
505 }
506
507 shp->shm_cprid = task_tgid_vnr(current);
508 shp->shm_lprid = 0;
509 shp->shm_atim = shp->shm_dtim = 0;
510 shp->shm_ctim = get_seconds();
511 shp->shm_segsz = size;
512 shp->shm_nattch = 0;
513 shp->shm_file = file;
514 shp->shm_creator = current;
515 /*
516 * shmid gets reported as "inode#" in /proc/pid/maps.
517 * proc-ps tools use this. Changing this will break them.
518 */
519 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
520
521 ns->shm_tot += numpages;
522 error = shp->shm_perm.id;
523 shm_unlock(shp);
524 return error;
525
526no_id:
527 if (is_file_hugepages(file) && shp->mlock_user)
528 user_shm_unlock(size, shp->mlock_user);
529 fput(file);
530no_file:
531 security_shm_free(shp);
532 ipc_rcu_putref(shp);
533 return error;
534}
535
536/*
537 * Called with shm_ids.rw_mutex and ipcp locked.
538 */
539static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
540{
541 struct shmid_kernel *shp;
542
543 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
544 return security_shm_associate(shp, shmflg);
545}
546
547/*
548 * Called with shm_ids.rw_mutex and ipcp locked.
549 */
550static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
551 struct ipc_params *params)
552{
553 struct shmid_kernel *shp;
554
555 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
556 if (shp->shm_segsz < params->u.size)
557 return -EINVAL;
558
559 return 0;
560}
561
562SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
563{
564 struct ipc_namespace *ns;
565 struct ipc_ops shm_ops;
566 struct ipc_params shm_params;
567
568 ns = current->nsproxy->ipc_ns;
569
570 shm_ops.getnew = newseg;
571 shm_ops.associate = shm_security;
572 shm_ops.more_checks = shm_more_checks;
573
574 shm_params.key = key;
575 shm_params.flg = shmflg;
576 shm_params.u.size = size;
577
578 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
579}
580
581static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
582{
583 switch(version) {
584 case IPC_64:
585 return copy_to_user(buf, in, sizeof(*in));
586 case IPC_OLD:
587 {
588 struct shmid_ds out;
589
590 memset(&out, 0, sizeof(out));
591 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
592 out.shm_segsz = in->shm_segsz;
593 out.shm_atime = in->shm_atime;
594 out.shm_dtime = in->shm_dtime;
595 out.shm_ctime = in->shm_ctime;
596 out.shm_cpid = in->shm_cpid;
597 out.shm_lpid = in->shm_lpid;
598 out.shm_nattch = in->shm_nattch;
599
600 return copy_to_user(buf, &out, sizeof(out));
601 }
602 default:
603 return -EINVAL;
604 }
605}
606
607static inline unsigned long
608copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
609{
610 switch(version) {
611 case IPC_64:
612 if (copy_from_user(out, buf, sizeof(*out)))
613 return -EFAULT;
614 return 0;
615 case IPC_OLD:
616 {
617 struct shmid_ds tbuf_old;
618
619 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
620 return -EFAULT;
621
622 out->shm_perm.uid = tbuf_old.shm_perm.uid;
623 out->shm_perm.gid = tbuf_old.shm_perm.gid;
624 out->shm_perm.mode = tbuf_old.shm_perm.mode;
625
626 return 0;
627 }
628 default:
629 return -EINVAL;
630 }
631}
632
633static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
634{
635 switch(version) {
636 case IPC_64:
637 return copy_to_user(buf, in, sizeof(*in));
638 case IPC_OLD:
639 {
640 struct shminfo out;
641
642 if(in->shmmax > INT_MAX)
643 out.shmmax = INT_MAX;
644 else
645 out.shmmax = (int)in->shmmax;
646
647 out.shmmin = in->shmmin;
648 out.shmmni = in->shmmni;
649 out.shmseg = in->shmseg;
650 out.shmall = in->shmall;
651
652 return copy_to_user(buf, &out, sizeof(out));
653 }
654 default:
655 return -EINVAL;
656 }
657}
658
659/*
660 * Calculate and add used RSS and swap pages of a shm.
661 * Called with shm_ids.rw_mutex held as a reader
662 */
663static void shm_add_rss_swap(struct shmid_kernel *shp,
664 unsigned long *rss_add, unsigned long *swp_add)
665{
666 struct inode *inode;
667
668 inode = shp->shm_file->f_path.dentry->d_inode;
669
670 if (is_file_hugepages(shp->shm_file)) {
671 struct address_space *mapping = inode->i_mapping;
672 struct hstate *h = hstate_file(shp->shm_file);
673 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
674 } else {
675#ifdef CONFIG_SHMEM
676 struct shmem_inode_info *info = SHMEM_I(inode);
677 spin_lock(&info->lock);
678 *rss_add += inode->i_mapping->nrpages;
679 *swp_add += info->swapped;
680 spin_unlock(&info->lock);
681#else
682 *rss_add += inode->i_mapping->nrpages;
683#endif
684 }
685}
686
687/*
688 * Called with shm_ids.rw_mutex held as a reader
689 */
690static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
691 unsigned long *swp)
692{
693 int next_id;
694 int total, in_use;
695
696 *rss = 0;
697 *swp = 0;
698
699 in_use = shm_ids(ns).in_use;
700
701 for (total = 0, next_id = 0; total < in_use; next_id++) {
702 struct kern_ipc_perm *ipc;
703 struct shmid_kernel *shp;
704
705 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
706 if (ipc == NULL)
707 continue;
708 shp = container_of(ipc, struct shmid_kernel, shm_perm);
709
710 shm_add_rss_swap(shp, rss, swp);
711
712 total++;
713 }
714}
715
716/*
717 * This function handles some shmctl commands which require the rw_mutex
718 * to be held in write mode.
719 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
720 */
721static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
722 struct shmid_ds __user *buf, int version)
723{
724 struct kern_ipc_perm *ipcp;
725 struct shmid64_ds shmid64;
726 struct shmid_kernel *shp;
727 int err;
728
729 if (cmd == IPC_SET) {
730 if (copy_shmid_from_user(&shmid64, buf, version))
731 return -EFAULT;
732 }
733
734 ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
735 &shmid64.shm_perm, 0);
736 if (IS_ERR(ipcp))
737 return PTR_ERR(ipcp);
738
739 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
740
741 err = security_shm_shmctl(shp, cmd);
742 if (err)
743 goto out_unlock;
744 switch (cmd) {
745 case IPC_RMID:
746 do_shm_rmid(ns, ipcp);
747 goto out_up;
748 case IPC_SET:
749 ipc_update_perm(&shmid64.shm_perm, ipcp);
750 shp->shm_ctim = get_seconds();
751 break;
752 default:
753 err = -EINVAL;
754 }
755out_unlock:
756 shm_unlock(shp);
757out_up:
758 up_write(&shm_ids(ns).rw_mutex);
759 return err;
760}
761
762SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
763{
764 struct shmid_kernel *shp;
765 int err, version;
766 struct ipc_namespace *ns;
767
768 if (cmd < 0 || shmid < 0) {
769 err = -EINVAL;
770 goto out;
771 }
772
773 version = ipc_parse_version(&cmd);
774 ns = current->nsproxy->ipc_ns;
775
776 switch (cmd) { /* replace with proc interface ? */
777 case IPC_INFO:
778 {
779 struct shminfo64 shminfo;
780
781 err = security_shm_shmctl(NULL, cmd);
782 if (err)
783 return err;
784
785 memset(&shminfo, 0, sizeof(shminfo));
786 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
787 shminfo.shmmax = ns->shm_ctlmax;
788 shminfo.shmall = ns->shm_ctlall;
789
790 shminfo.shmmin = SHMMIN;
791 if(copy_shminfo_to_user (buf, &shminfo, version))
792 return -EFAULT;
793
794 down_read(&shm_ids(ns).rw_mutex);
795 err = ipc_get_maxid(&shm_ids(ns));
796 up_read(&shm_ids(ns).rw_mutex);
797
798 if(err<0)
799 err = 0;
800 goto out;
801 }
802 case SHM_INFO:
803 {
804 struct shm_info shm_info;
805
806 err = security_shm_shmctl(NULL, cmd);
807 if (err)
808 return err;
809
810 memset(&shm_info, 0, sizeof(shm_info));
811 down_read(&shm_ids(ns).rw_mutex);
812 shm_info.used_ids = shm_ids(ns).in_use;
813 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
814 shm_info.shm_tot = ns->shm_tot;
815 shm_info.swap_attempts = 0;
816 shm_info.swap_successes = 0;
817 err = ipc_get_maxid(&shm_ids(ns));
818 up_read(&shm_ids(ns).rw_mutex);
819 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
820 err = -EFAULT;
821 goto out;
822 }
823
824 err = err < 0 ? 0 : err;
825 goto out;
826 }
827 case SHM_STAT:
828 case IPC_STAT:
829 {
830 struct shmid64_ds tbuf;
831 int result;
832
833 if (cmd == SHM_STAT) {
834 shp = shm_lock(ns, shmid);
835 if (IS_ERR(shp)) {
836 err = PTR_ERR(shp);
837 goto out;
838 }
839 result = shp->shm_perm.id;
840 } else {
841 shp = shm_lock_check(ns, shmid);
842 if (IS_ERR(shp)) {
843 err = PTR_ERR(shp);
844 goto out;
845 }
846 result = 0;
847 }
848 err = -EACCES;
849 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
850 goto out_unlock;
851 err = security_shm_shmctl(shp, cmd);
852 if (err)
853 goto out_unlock;
854 memset(&tbuf, 0, sizeof(tbuf));
855 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
856 tbuf.shm_segsz = shp->shm_segsz;
857 tbuf.shm_atime = shp->shm_atim;
858 tbuf.shm_dtime = shp->shm_dtim;
859 tbuf.shm_ctime = shp->shm_ctim;
860 tbuf.shm_cpid = shp->shm_cprid;
861 tbuf.shm_lpid = shp->shm_lprid;
862 tbuf.shm_nattch = shp->shm_nattch;
863 shm_unlock(shp);
864 if(copy_shmid_to_user (buf, &tbuf, version))
865 err = -EFAULT;
866 else
867 err = result;
868 goto out;
869 }
870 case SHM_LOCK:
871 case SHM_UNLOCK:
872 {
873 struct file *uninitialized_var(shm_file);
874
875 lru_add_drain_all(); /* drain pagevecs to lru lists */
876
877 shp = shm_lock_check(ns, shmid);
878 if (IS_ERR(shp)) {
879 err = PTR_ERR(shp);
880 goto out;
881 }
882
883 audit_ipc_obj(&(shp->shm_perm));
884
885 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
886 uid_t euid = current_euid();
887 err = -EPERM;
888 if (euid != shp->shm_perm.uid &&
889 euid != shp->shm_perm.cuid)
890 goto out_unlock;
891 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
892 goto out_unlock;
893 }
894
895 err = security_shm_shmctl(shp, cmd);
896 if (err)
897 goto out_unlock;
898
899 if(cmd==SHM_LOCK) {
900 struct user_struct *user = current_user();
901 if (!is_file_hugepages(shp->shm_file)) {
902 err = shmem_lock(shp->shm_file, 1, user);
903 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
904 shp->shm_perm.mode |= SHM_LOCKED;
905 shp->mlock_user = user;
906 }
907 }
908 } else if (!is_file_hugepages(shp->shm_file)) {
909 shmem_lock(shp->shm_file, 0, shp->mlock_user);
910 shp->shm_perm.mode &= ~SHM_LOCKED;
911 shp->mlock_user = NULL;
912 }
913 shm_unlock(shp);
914 goto out;
915 }
916 case IPC_RMID:
917 case IPC_SET:
918 err = shmctl_down(ns, shmid, cmd, buf, version);
919 return err;
920 default:
921 return -EINVAL;
922 }
923
924out_unlock:
925 shm_unlock(shp);
926out:
927 return err;
928}
929
930/*
931 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
932 *
933 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
934 * "raddr" thing points to kernel space, and there has to be a wrapper around
935 * this.
936 */
937long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
938{
939 struct shmid_kernel *shp;
940 unsigned long addr;
941 unsigned long size;
942 struct file * file;
943 int err;
944 unsigned long flags;
945 unsigned long prot;
946 int acc_mode;
947 unsigned long user_addr;
948 struct ipc_namespace *ns;
949 struct shm_file_data *sfd;
950 struct path path;
951 fmode_t f_mode;
952
953 err = -EINVAL;
954 if (shmid < 0)
955 goto out;
956 else if ((addr = (ulong)shmaddr)) {
957 if (addr & (SHMLBA-1)) {
958 if (shmflg & SHM_RND)
959 addr &= ~(SHMLBA-1); /* round down */
960 else
961#ifndef __ARCH_FORCE_SHMLBA
962 if (addr & ~PAGE_MASK)
963#endif
964 goto out;
965 }
966 flags = MAP_SHARED | MAP_FIXED;
967 } else {
968 if ((shmflg & SHM_REMAP))
969 goto out;
970
971 flags = MAP_SHARED;
972 }
973
974 if (shmflg & SHM_RDONLY) {
975 prot = PROT_READ;
976 acc_mode = S_IRUGO;
977 f_mode = FMODE_READ;
978 } else {
979 prot = PROT_READ | PROT_WRITE;
980 acc_mode = S_IRUGO | S_IWUGO;
981 f_mode = FMODE_READ | FMODE_WRITE;
982 }
983 if (shmflg & SHM_EXEC) {
984 prot |= PROT_EXEC;
985 acc_mode |= S_IXUGO;
986 }
987
988 /*
989 * We cannot rely on the fs check since SYSV IPC does have an
990 * additional creator id...
991 */
992 ns = current->nsproxy->ipc_ns;
993 shp = shm_lock_check(ns, shmid);
994 if (IS_ERR(shp)) {
995 err = PTR_ERR(shp);
996 goto out;
997 }
998
999 err = -EACCES;
1000 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1001 goto out_unlock;
1002
1003 err = security_shm_shmat(shp, shmaddr, shmflg);
1004 if (err)
1005 goto out_unlock;
1006
1007 path = shp->shm_file->f_path;
1008 path_get(&path);
1009 shp->shm_nattch++;
1010 size = i_size_read(path.dentry->d_inode);
1011 shm_unlock(shp);
1012
1013 err = -ENOMEM;
1014 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1015 if (!sfd)
1016 goto out_put_dentry;
1017
1018 file = alloc_file(&path, f_mode,
1019 is_file_hugepages(shp->shm_file) ?
1020 &shm_file_operations_huge :
1021 &shm_file_operations);
1022 if (!file)
1023 goto out_free;
1024
1025 file->private_data = sfd;
1026 file->f_mapping = shp->shm_file->f_mapping;
1027 sfd->id = shp->shm_perm.id;
1028 sfd->ns = get_ipc_ns(ns);
1029 sfd->file = shp->shm_file;
1030 sfd->vm_ops = NULL;
1031
1032 down_write(¤t->mm->mmap_sem);
1033 if (addr && !(shmflg & SHM_REMAP)) {
1034 err = -EINVAL;
1035 if (find_vma_intersection(current->mm, addr, addr + size))
1036 goto invalid;
1037 /*
1038 * If shm segment goes below stack, make sure there is some
1039 * space left for the stack to grow (at least 4 pages).
1040 */
1041 if (addr < current->mm->start_stack &&
1042 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1043 goto invalid;
1044 }
1045
1046 user_addr = do_mmap (file, addr, size, prot, flags, 0);
1047 *raddr = user_addr;
1048 err = 0;
1049 if (IS_ERR_VALUE(user_addr))
1050 err = (long)user_addr;
1051invalid:
1052 up_write(¤t->mm->mmap_sem);
1053
1054 fput(file);
1055
1056out_nattch:
1057 down_write(&shm_ids(ns).rw_mutex);
1058 shp = shm_lock(ns, shmid);
1059 BUG_ON(IS_ERR(shp));
1060 shp->shm_nattch--;
1061 if (shm_may_destroy(ns, shp))
1062 shm_destroy(ns, shp);
1063 else
1064 shm_unlock(shp);
1065 up_write(&shm_ids(ns).rw_mutex);
1066
1067out:
1068 return err;
1069
1070out_unlock:
1071 shm_unlock(shp);
1072 goto out;
1073
1074out_free:
1075 kfree(sfd);
1076out_put_dentry:
1077 path_put(&path);
1078 goto out_nattch;
1079}
1080
1081SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1082{
1083 unsigned long ret;
1084 long err;
1085
1086 err = do_shmat(shmid, shmaddr, shmflg, &ret);
1087 if (err)
1088 return err;
1089 force_successful_syscall_return();
1090 return (long)ret;
1091}
1092
1093/*
1094 * detach and kill segment if marked destroyed.
1095 * The work is done in shm_close.
1096 */
1097SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1098{
1099 struct mm_struct *mm = current->mm;
1100 struct vm_area_struct *vma;
1101 unsigned long addr = (unsigned long)shmaddr;
1102 int retval = -EINVAL;
1103#ifdef CONFIG_MMU
1104 loff_t size = 0;
1105 struct vm_area_struct *next;
1106#endif
1107
1108 if (addr & ~PAGE_MASK)
1109 return retval;
1110
1111 down_write(&mm->mmap_sem);
1112
1113 /*
1114 * This function tries to be smart and unmap shm segments that
1115 * were modified by partial mlock or munmap calls:
1116 * - It first determines the size of the shm segment that should be
1117 * unmapped: It searches for a vma that is backed by shm and that
1118 * started at address shmaddr. It records it's size and then unmaps
1119 * it.
1120 * - Then it unmaps all shm vmas that started at shmaddr and that
1121 * are within the initially determined size.
1122 * Errors from do_munmap are ignored: the function only fails if
1123 * it's called with invalid parameters or if it's called to unmap
1124 * a part of a vma. Both calls in this function are for full vmas,
1125 * the parameters are directly copied from the vma itself and always
1126 * valid - therefore do_munmap cannot fail. (famous last words?)
1127 */
1128 /*
1129 * If it had been mremap()'d, the starting address would not
1130 * match the usual checks anyway. So assume all vma's are
1131 * above the starting address given.
1132 */
1133 vma = find_vma(mm, addr);
1134
1135#ifdef CONFIG_MMU
1136 while (vma) {
1137 next = vma->vm_next;
1138
1139 /*
1140 * Check if the starting address would match, i.e. it's
1141 * a fragment created by mprotect() and/or munmap(), or it
1142 * otherwise it starts at this address with no hassles.
1143 */
1144 if ((vma->vm_ops == &shm_vm_ops) &&
1145 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1146
1147
1148 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1149 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1150 /*
1151 * We discovered the size of the shm segment, so
1152 * break out of here and fall through to the next
1153 * loop that uses the size information to stop
1154 * searching for matching vma's.
1155 */
1156 retval = 0;
1157 vma = next;
1158 break;
1159 }
1160 vma = next;
1161 }
1162
1163 /*
1164 * We need look no further than the maximum address a fragment
1165 * could possibly have landed at. Also cast things to loff_t to
1166 * prevent overflows and make comparisons vs. equal-width types.
1167 */
1168 size = PAGE_ALIGN(size);
1169 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1170 next = vma->vm_next;
1171
1172 /* finding a matching vma now does not alter retval */
1173 if ((vma->vm_ops == &shm_vm_ops) &&
1174 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1175
1176 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1177 vma = next;
1178 }
1179
1180#else /* CONFIG_MMU */
1181 /* under NOMMU conditions, the exact address to be destroyed must be
1182 * given */
1183 retval = -EINVAL;
1184 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1185 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1186 retval = 0;
1187 }
1188
1189#endif
1190
1191 up_write(&mm->mmap_sem);
1192 return retval;
1193}
1194
1195#ifdef CONFIG_PROC_FS
1196static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1197{
1198 struct shmid_kernel *shp = it;
1199 unsigned long rss = 0, swp = 0;
1200
1201 shm_add_rss_swap(shp, &rss, &swp);
1202
1203#if BITS_PER_LONG <= 32
1204#define SIZE_SPEC "%10lu"
1205#else
1206#define SIZE_SPEC "%21lu"
1207#endif
1208
1209 return seq_printf(s,
1210 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1211 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1212 SIZE_SPEC " " SIZE_SPEC "\n",
1213 shp->shm_perm.key,
1214 shp->shm_perm.id,
1215 shp->shm_perm.mode,
1216 shp->shm_segsz,
1217 shp->shm_cprid,
1218 shp->shm_lprid,
1219 shp->shm_nattch,
1220 shp->shm_perm.uid,
1221 shp->shm_perm.gid,
1222 shp->shm_perm.cuid,
1223 shp->shm_perm.cgid,
1224 shp->shm_atim,
1225 shp->shm_dtim,
1226 shp->shm_ctim,
1227 rss * PAGE_SIZE,
1228 swp * PAGE_SIZE);
1229}
1230#endif
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