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