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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 | #include <linux/ima.h> | |
43 | ||
44 | #include <asm/uaccess.h> | |
45 | ||
46 | #include "util.h" | |
47 | ||
48 | struct shm_file_data { | |
49 | int id; | |
50 | struct ipc_namespace *ns; | |
51 | struct file *file; | |
52 | const struct vm_operations_struct *vm_ops; | |
53 | }; | |
54 | ||
55 | #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data)) | |
56 | ||
57 | static const struct file_operations shm_file_operations; | |
58 | static struct vm_operations_struct shm_vm_ops; | |
59 | ||
60 | #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS]) | |
61 | ||
62 | #define shm_unlock(shp) \ | |
63 | ipc_unlock(&(shp)->shm_perm) | |
64 | ||
65 | static int newseg(struct ipc_namespace *, struct ipc_params *); | |
66 | static void shm_open(struct vm_area_struct *vma); | |
67 | static void shm_close(struct vm_area_struct *vma); | |
68 | static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp); | |
69 | #ifdef CONFIG_PROC_FS | |
70 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it); | |
71 | #endif | |
72 | ||
73 | void shm_init_ns(struct ipc_namespace *ns) | |
74 | { | |
75 | ns->shm_ctlmax = SHMMAX; | |
76 | ns->shm_ctlall = SHMALL; | |
77 | ns->shm_ctlmni = SHMMNI; | |
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 | */ | |
86 | static 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 | |
101 | void shm_exit_ns(struct ipc_namespace *ns) | |
102 | { | |
103 | free_ipcs(ns, &shm_ids(ns), do_shm_rmid); | |
104 | } | |
105 | #endif | |
106 | ||
107 | void __init shm_init (void) | |
108 | { | |
109 | shm_init_ns(&init_ipc_ns); | |
110 | ipc_init_proc_interface("sysvipc/shm", | |
111 | " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n", | |
112 | IPC_SHM_IDS, sysvipc_shm_proc_show); | |
113 | } | |
114 | ||
115 | /* | |
116 | * shm_lock_(check_) routines are called in the paths where the rw_mutex | |
117 | * is not necessarily held. | |
118 | */ | |
119 | static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id) | |
120 | { | |
121 | struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); | |
122 | ||
123 | if (IS_ERR(ipcp)) | |
124 | return (struct shmid_kernel *)ipcp; | |
125 | ||
126 | return container_of(ipcp, struct shmid_kernel, shm_perm); | |
127 | } | |
128 | ||
129 | static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns, | |
130 | int id) | |
131 | { | |
132 | struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id); | |
133 | ||
134 | if (IS_ERR(ipcp)) | |
135 | return (struct shmid_kernel *)ipcp; | |
136 | ||
137 | return container_of(ipcp, struct shmid_kernel, shm_perm); | |
138 | } | |
139 | ||
140 | static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s) | |
141 | { | |
142 | ipc_rmid(&shm_ids(ns), &s->shm_perm); | |
143 | } | |
144 | ||
145 | ||
146 | /* This is called by fork, once for every shm attach. */ | |
147 | static void shm_open(struct vm_area_struct *vma) | |
148 | { | |
149 | struct file *file = vma->vm_file; | |
150 | struct shm_file_data *sfd = shm_file_data(file); | |
151 | struct shmid_kernel *shp; | |
152 | ||
153 | shp = shm_lock(sfd->ns, sfd->id); | |
154 | BUG_ON(IS_ERR(shp)); | |
155 | shp->shm_atim = get_seconds(); | |
156 | shp->shm_lprid = task_tgid_vnr(current); | |
157 | shp->shm_nattch++; | |
158 | shm_unlock(shp); | |
159 | } | |
160 | ||
161 | /* | |
162 | * shm_destroy - free the struct shmid_kernel | |
163 | * | |
164 | * @ns: namespace | |
165 | * @shp: struct to free | |
166 | * | |
167 | * It has to be called with shp and shm_ids.rw_mutex (writer) locked, | |
168 | * but returns with shp unlocked and freed. | |
169 | */ | |
170 | static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) | |
171 | { | |
172 | ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
173 | shm_rmid(ns, shp); | |
174 | shm_unlock(shp); | |
175 | if (!is_file_hugepages(shp->shm_file)) | |
176 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
177 | else | |
178 | user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size, | |
179 | shp->mlock_user); | |
180 | fput (shp->shm_file); | |
181 | security_shm_free(shp); | |
182 | ipc_rcu_putref(shp); | |
183 | } | |
184 | ||
185 | /* | |
186 | * remove the attach descriptor vma. | |
187 | * free memory for segment if it is marked destroyed. | |
188 | * The descriptor has already been removed from the current->mm->mmap list | |
189 | * and will later be kfree()d. | |
190 | */ | |
191 | static void shm_close(struct vm_area_struct *vma) | |
192 | { | |
193 | struct file * file = vma->vm_file; | |
194 | struct shm_file_data *sfd = shm_file_data(file); | |
195 | struct shmid_kernel *shp; | |
196 | struct ipc_namespace *ns = sfd->ns; | |
197 | ||
198 | down_write(&shm_ids(ns).rw_mutex); | |
199 | /* remove from the list of attaches of the shm segment */ | |
200 | shp = shm_lock(ns, sfd->id); | |
201 | BUG_ON(IS_ERR(shp)); | |
202 | shp->shm_lprid = task_tgid_vnr(current); | |
203 | shp->shm_dtim = get_seconds(); | |
204 | shp->shm_nattch--; | |
205 | if(shp->shm_nattch == 0 && | |
206 | shp->shm_perm.mode & SHM_DEST) | |
207 | shm_destroy(ns, shp); | |
208 | else | |
209 | shm_unlock(shp); | |
210 | up_write(&shm_ids(ns).rw_mutex); | |
211 | } | |
212 | ||
213 | static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
214 | { | |
215 | struct file *file = vma->vm_file; | |
216 | struct shm_file_data *sfd = shm_file_data(file); | |
217 | ||
218 | return sfd->vm_ops->fault(vma, vmf); | |
219 | } | |
220 | ||
221 | #ifdef CONFIG_NUMA | |
222 | static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) | |
223 | { | |
224 | struct file *file = vma->vm_file; | |
225 | struct shm_file_data *sfd = shm_file_data(file); | |
226 | int err = 0; | |
227 | if (sfd->vm_ops->set_policy) | |
228 | err = sfd->vm_ops->set_policy(vma, new); | |
229 | return err; | |
230 | } | |
231 | ||
232 | static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, | |
233 | unsigned long addr) | |
234 | { | |
235 | struct file *file = vma->vm_file; | |
236 | struct shm_file_data *sfd = shm_file_data(file); | |
237 | struct mempolicy *pol = NULL; | |
238 | ||
239 | if (sfd->vm_ops->get_policy) | |
240 | pol = sfd->vm_ops->get_policy(vma, addr); | |
241 | else if (vma->vm_policy) | |
242 | pol = vma->vm_policy; | |
243 | ||
244 | return pol; | |
245 | } | |
246 | #endif | |
247 | ||
248 | static int shm_mmap(struct file * file, struct vm_area_struct * vma) | |
249 | { | |
250 | struct shm_file_data *sfd = shm_file_data(file); | |
251 | int ret; | |
252 | ||
253 | ret = sfd->file->f_op->mmap(sfd->file, vma); | |
254 | if (ret != 0) | |
255 | return ret; | |
256 | sfd->vm_ops = vma->vm_ops; | |
257 | #ifdef CONFIG_MMU | |
258 | BUG_ON(!sfd->vm_ops->fault); | |
259 | #endif | |
260 | vma->vm_ops = &shm_vm_ops; | |
261 | shm_open(vma); | |
262 | ||
263 | return ret; | |
264 | } | |
265 | ||
266 | static int shm_release(struct inode *ino, struct file *file) | |
267 | { | |
268 | struct shm_file_data *sfd = shm_file_data(file); | |
269 | ||
270 | put_ipc_ns(sfd->ns); | |
271 | shm_file_data(file) = NULL; | |
272 | kfree(sfd); | |
273 | return 0; | |
274 | } | |
275 | ||
276 | static int shm_fsync(struct file *file, struct dentry *dentry, int datasync) | |
277 | { | |
278 | int (*fsync) (struct file *, struct dentry *, int datasync); | |
279 | struct shm_file_data *sfd = shm_file_data(file); | |
280 | int ret = -EINVAL; | |
281 | ||
282 | fsync = sfd->file->f_op->fsync; | |
283 | if (fsync) | |
284 | ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync); | |
285 | return ret; | |
286 | } | |
287 | ||
288 | static unsigned long shm_get_unmapped_area(struct file *file, | |
289 | unsigned long addr, unsigned long len, unsigned long pgoff, | |
290 | unsigned long flags) | |
291 | { | |
292 | struct shm_file_data *sfd = shm_file_data(file); | |
293 | return get_unmapped_area(sfd->file, addr, len, pgoff, flags); | |
294 | } | |
295 | ||
296 | int is_file_shm_hugepages(struct file *file) | |
297 | { | |
298 | int ret = 0; | |
299 | ||
300 | if (file->f_op == &shm_file_operations) { | |
301 | struct shm_file_data *sfd; | |
302 | sfd = shm_file_data(file); | |
303 | ret = is_file_hugepages(sfd->file); | |
304 | } | |
305 | return ret; | |
306 | } | |
307 | ||
308 | static const struct file_operations shm_file_operations = { | |
309 | .mmap = shm_mmap, | |
310 | .fsync = shm_fsync, | |
311 | .release = shm_release, | |
312 | .get_unmapped_area = shm_get_unmapped_area, | |
313 | }; | |
314 | ||
315 | static struct vm_operations_struct shm_vm_ops = { | |
316 | .open = shm_open, /* callback for a new vm-area open */ | |
317 | .close = shm_close, /* callback for when the vm-area is released */ | |
318 | .fault = shm_fault, | |
319 | #if defined(CONFIG_NUMA) | |
320 | .set_policy = shm_set_policy, | |
321 | .get_policy = shm_get_policy, | |
322 | #endif | |
323 | }; | |
324 | ||
325 | /** | |
326 | * newseg - Create a new shared memory segment | |
327 | * @ns: namespace | |
328 | * @params: ptr to the structure that contains key, size and shmflg | |
329 | * | |
330 | * Called with shm_ids.rw_mutex held as a writer. | |
331 | */ | |
332 | ||
333 | static int newseg(struct ipc_namespace *ns, struct ipc_params *params) | |
334 | { | |
335 | key_t key = params->key; | |
336 | int shmflg = params->flg; | |
337 | size_t size = params->u.size; | |
338 | int error; | |
339 | struct shmid_kernel *shp; | |
340 | int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; | |
341 | struct file * file; | |
342 | char name[13]; | |
343 | int id; | |
344 | int acctflag = 0; | |
345 | ||
346 | if (size < SHMMIN || size > ns->shm_ctlmax) | |
347 | return -EINVAL; | |
348 | ||
349 | if (ns->shm_tot + numpages > ns->shm_ctlall) | |
350 | return -ENOSPC; | |
351 | ||
352 | shp = ipc_rcu_alloc(sizeof(*shp)); | |
353 | if (!shp) | |
354 | return -ENOMEM; | |
355 | ||
356 | shp->shm_perm.key = key; | |
357 | shp->shm_perm.mode = (shmflg & S_IRWXUGO); | |
358 | shp->mlock_user = NULL; | |
359 | ||
360 | shp->shm_perm.security = NULL; | |
361 | error = security_shm_alloc(shp); | |
362 | if (error) { | |
363 | ipc_rcu_putref(shp); | |
364 | return error; | |
365 | } | |
366 | ||
367 | sprintf (name, "SYSV%08x", key); | |
368 | if (shmflg & SHM_HUGETLB) { | |
369 | /* hugetlb_file_setup applies strict accounting */ | |
370 | if (shmflg & SHM_NORESERVE) | |
371 | acctflag = VM_NORESERVE; | |
372 | file = hugetlb_file_setup(name, size, acctflag); | |
373 | shp->mlock_user = current_user(); | |
374 | } else { | |
375 | /* | |
376 | * Do not allow no accounting for OVERCOMMIT_NEVER, even | |
377 | * if it's asked for. | |
378 | */ | |
379 | if ((shmflg & SHM_NORESERVE) && | |
380 | sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
381 | acctflag = VM_NORESERVE; | |
382 | file = shmem_file_setup(name, size, acctflag); | |
383 | } | |
384 | error = PTR_ERR(file); | |
385 | if (IS_ERR(file)) | |
386 | goto no_file; | |
387 | ima_shm_check(file); | |
388 | ||
389 | id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); | |
390 | if (id < 0) { | |
391 | error = id; | |
392 | goto no_id; | |
393 | } | |
394 | ||
395 | shp->shm_cprid = task_tgid_vnr(current); | |
396 | shp->shm_lprid = 0; | |
397 | shp->shm_atim = shp->shm_dtim = 0; | |
398 | shp->shm_ctim = get_seconds(); | |
399 | shp->shm_segsz = size; | |
400 | shp->shm_nattch = 0; | |
401 | shp->shm_file = file; | |
402 | /* | |
403 | * shmid gets reported as "inode#" in /proc/pid/maps. | |
404 | * proc-ps tools use this. Changing this will break them. | |
405 | */ | |
406 | file->f_dentry->d_inode->i_ino = shp->shm_perm.id; | |
407 | ||
408 | ns->shm_tot += numpages; | |
409 | error = shp->shm_perm.id; | |
410 | shm_unlock(shp); | |
411 | return error; | |
412 | ||
413 | no_id: | |
414 | fput(file); | |
415 | no_file: | |
416 | security_shm_free(shp); | |
417 | ipc_rcu_putref(shp); | |
418 | return error; | |
419 | } | |
420 | ||
421 | /* | |
422 | * Called with shm_ids.rw_mutex and ipcp locked. | |
423 | */ | |
424 | static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) | |
425 | { | |
426 | struct shmid_kernel *shp; | |
427 | ||
428 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); | |
429 | return security_shm_associate(shp, shmflg); | |
430 | } | |
431 | ||
432 | /* | |
433 | * Called with shm_ids.rw_mutex and ipcp locked. | |
434 | */ | |
435 | static inline int shm_more_checks(struct kern_ipc_perm *ipcp, | |
436 | struct ipc_params *params) | |
437 | { | |
438 | struct shmid_kernel *shp; | |
439 | ||
440 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); | |
441 | if (shp->shm_segsz < params->u.size) | |
442 | return -EINVAL; | |
443 | ||
444 | return 0; | |
445 | } | |
446 | ||
447 | SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg) | |
448 | { | |
449 | struct ipc_namespace *ns; | |
450 | struct ipc_ops shm_ops; | |
451 | struct ipc_params shm_params; | |
452 | ||
453 | ns = current->nsproxy->ipc_ns; | |
454 | ||
455 | shm_ops.getnew = newseg; | |
456 | shm_ops.associate = shm_security; | |
457 | shm_ops.more_checks = shm_more_checks; | |
458 | ||
459 | shm_params.key = key; | |
460 | shm_params.flg = shmflg; | |
461 | shm_params.u.size = size; | |
462 | ||
463 | return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params); | |
464 | } | |
465 | ||
466 | static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) | |
467 | { | |
468 | switch(version) { | |
469 | case IPC_64: | |
470 | return copy_to_user(buf, in, sizeof(*in)); | |
471 | case IPC_OLD: | |
472 | { | |
473 | struct shmid_ds out; | |
474 | ||
475 | ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); | |
476 | out.shm_segsz = in->shm_segsz; | |
477 | out.shm_atime = in->shm_atime; | |
478 | out.shm_dtime = in->shm_dtime; | |
479 | out.shm_ctime = in->shm_ctime; | |
480 | out.shm_cpid = in->shm_cpid; | |
481 | out.shm_lpid = in->shm_lpid; | |
482 | out.shm_nattch = in->shm_nattch; | |
483 | ||
484 | return copy_to_user(buf, &out, sizeof(out)); | |
485 | } | |
486 | default: | |
487 | return -EINVAL; | |
488 | } | |
489 | } | |
490 | ||
491 | static inline unsigned long | |
492 | copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version) | |
493 | { | |
494 | switch(version) { | |
495 | case IPC_64: | |
496 | if (copy_from_user(out, buf, sizeof(*out))) | |
497 | return -EFAULT; | |
498 | return 0; | |
499 | case IPC_OLD: | |
500 | { | |
501 | struct shmid_ds tbuf_old; | |
502 | ||
503 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) | |
504 | return -EFAULT; | |
505 | ||
506 | out->shm_perm.uid = tbuf_old.shm_perm.uid; | |
507 | out->shm_perm.gid = tbuf_old.shm_perm.gid; | |
508 | out->shm_perm.mode = tbuf_old.shm_perm.mode; | |
509 | ||
510 | return 0; | |
511 | } | |
512 | default: | |
513 | return -EINVAL; | |
514 | } | |
515 | } | |
516 | ||
517 | static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) | |
518 | { | |
519 | switch(version) { | |
520 | case IPC_64: | |
521 | return copy_to_user(buf, in, sizeof(*in)); | |
522 | case IPC_OLD: | |
523 | { | |
524 | struct shminfo out; | |
525 | ||
526 | if(in->shmmax > INT_MAX) | |
527 | out.shmmax = INT_MAX; | |
528 | else | |
529 | out.shmmax = (int)in->shmmax; | |
530 | ||
531 | out.shmmin = in->shmmin; | |
532 | out.shmmni = in->shmmni; | |
533 | out.shmseg = in->shmseg; | |
534 | out.shmall = in->shmall; | |
535 | ||
536 | return copy_to_user(buf, &out, sizeof(out)); | |
537 | } | |
538 | default: | |
539 | return -EINVAL; | |
540 | } | |
541 | } | |
542 | ||
543 | /* | |
544 | * Called with shm_ids.rw_mutex held as a reader | |
545 | */ | |
546 | static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, | |
547 | unsigned long *swp) | |
548 | { | |
549 | int next_id; | |
550 | int total, in_use; | |
551 | ||
552 | *rss = 0; | |
553 | *swp = 0; | |
554 | ||
555 | in_use = shm_ids(ns).in_use; | |
556 | ||
557 | for (total = 0, next_id = 0; total < in_use; next_id++) { | |
558 | struct kern_ipc_perm *ipc; | |
559 | struct shmid_kernel *shp; | |
560 | struct inode *inode; | |
561 | ||
562 | ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id); | |
563 | if (ipc == NULL) | |
564 | continue; | |
565 | shp = container_of(ipc, struct shmid_kernel, shm_perm); | |
566 | ||
567 | inode = shp->shm_file->f_path.dentry->d_inode; | |
568 | ||
569 | if (is_file_hugepages(shp->shm_file)) { | |
570 | struct address_space *mapping = inode->i_mapping; | |
571 | struct hstate *h = hstate_file(shp->shm_file); | |
572 | *rss += pages_per_huge_page(h) * mapping->nrpages; | |
573 | } else { | |
574 | #ifdef CONFIG_SHMEM | |
575 | struct shmem_inode_info *info = SHMEM_I(inode); | |
576 | spin_lock(&info->lock); | |
577 | *rss += inode->i_mapping->nrpages; | |
578 | *swp += info->swapped; | |
579 | spin_unlock(&info->lock); | |
580 | #else | |
581 | *rss += inode->i_mapping->nrpages; | |
582 | #endif | |
583 | } | |
584 | ||
585 | total++; | |
586 | } | |
587 | } | |
588 | ||
589 | /* | |
590 | * This function handles some shmctl commands which require the rw_mutex | |
591 | * to be held in write mode. | |
592 | * NOTE: no locks must be held, the rw_mutex is taken inside this function. | |
593 | */ | |
594 | static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, | |
595 | struct shmid_ds __user *buf, int version) | |
596 | { | |
597 | struct kern_ipc_perm *ipcp; | |
598 | struct shmid64_ds shmid64; | |
599 | struct shmid_kernel *shp; | |
600 | int err; | |
601 | ||
602 | if (cmd == IPC_SET) { | |
603 | if (copy_shmid_from_user(&shmid64, buf, version)) | |
604 | return -EFAULT; | |
605 | } | |
606 | ||
607 | ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0); | |
608 | if (IS_ERR(ipcp)) | |
609 | return PTR_ERR(ipcp); | |
610 | ||
611 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); | |
612 | ||
613 | err = security_shm_shmctl(shp, cmd); | |
614 | if (err) | |
615 | goto out_unlock; | |
616 | switch (cmd) { | |
617 | case IPC_RMID: | |
618 | do_shm_rmid(ns, ipcp); | |
619 | goto out_up; | |
620 | case IPC_SET: | |
621 | ipc_update_perm(&shmid64.shm_perm, ipcp); | |
622 | shp->shm_ctim = get_seconds(); | |
623 | break; | |
624 | default: | |
625 | err = -EINVAL; | |
626 | } | |
627 | out_unlock: | |
628 | shm_unlock(shp); | |
629 | out_up: | |
630 | up_write(&shm_ids(ns).rw_mutex); | |
631 | return err; | |
632 | } | |
633 | ||
634 | SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) | |
635 | { | |
636 | struct shmid_kernel *shp; | |
637 | int err, version; | |
638 | struct ipc_namespace *ns; | |
639 | ||
640 | if (cmd < 0 || shmid < 0) { | |
641 | err = -EINVAL; | |
642 | goto out; | |
643 | } | |
644 | ||
645 | version = ipc_parse_version(&cmd); | |
646 | ns = current->nsproxy->ipc_ns; | |
647 | ||
648 | switch (cmd) { /* replace with proc interface ? */ | |
649 | case IPC_INFO: | |
650 | { | |
651 | struct shminfo64 shminfo; | |
652 | ||
653 | err = security_shm_shmctl(NULL, cmd); | |
654 | if (err) | |
655 | return err; | |
656 | ||
657 | memset(&shminfo, 0, sizeof(shminfo)); | |
658 | shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; | |
659 | shminfo.shmmax = ns->shm_ctlmax; | |
660 | shminfo.shmall = ns->shm_ctlall; | |
661 | ||
662 | shminfo.shmmin = SHMMIN; | |
663 | if(copy_shminfo_to_user (buf, &shminfo, version)) | |
664 | return -EFAULT; | |
665 | ||
666 | down_read(&shm_ids(ns).rw_mutex); | |
667 | err = ipc_get_maxid(&shm_ids(ns)); | |
668 | up_read(&shm_ids(ns).rw_mutex); | |
669 | ||
670 | if(err<0) | |
671 | err = 0; | |
672 | goto out; | |
673 | } | |
674 | case SHM_INFO: | |
675 | { | |
676 | struct shm_info shm_info; | |
677 | ||
678 | err = security_shm_shmctl(NULL, cmd); | |
679 | if (err) | |
680 | return err; | |
681 | ||
682 | memset(&shm_info, 0, sizeof(shm_info)); | |
683 | down_read(&shm_ids(ns).rw_mutex); | |
684 | shm_info.used_ids = shm_ids(ns).in_use; | |
685 | shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp); | |
686 | shm_info.shm_tot = ns->shm_tot; | |
687 | shm_info.swap_attempts = 0; | |
688 | shm_info.swap_successes = 0; | |
689 | err = ipc_get_maxid(&shm_ids(ns)); | |
690 | up_read(&shm_ids(ns).rw_mutex); | |
691 | if (copy_to_user(buf, &shm_info, sizeof(shm_info))) { | |
692 | err = -EFAULT; | |
693 | goto out; | |
694 | } | |
695 | ||
696 | err = err < 0 ? 0 : err; | |
697 | goto out; | |
698 | } | |
699 | case SHM_STAT: | |
700 | case IPC_STAT: | |
701 | { | |
702 | struct shmid64_ds tbuf; | |
703 | int result; | |
704 | ||
705 | if (cmd == SHM_STAT) { | |
706 | shp = shm_lock(ns, shmid); | |
707 | if (IS_ERR(shp)) { | |
708 | err = PTR_ERR(shp); | |
709 | goto out; | |
710 | } | |
711 | result = shp->shm_perm.id; | |
712 | } else { | |
713 | shp = shm_lock_check(ns, shmid); | |
714 | if (IS_ERR(shp)) { | |
715 | err = PTR_ERR(shp); | |
716 | goto out; | |
717 | } | |
718 | result = 0; | |
719 | } | |
720 | err = -EACCES; | |
721 | if (ipcperms (&shp->shm_perm, S_IRUGO)) | |
722 | goto out_unlock; | |
723 | err = security_shm_shmctl(shp, cmd); | |
724 | if (err) | |
725 | goto out_unlock; | |
726 | memset(&tbuf, 0, sizeof(tbuf)); | |
727 | kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); | |
728 | tbuf.shm_segsz = shp->shm_segsz; | |
729 | tbuf.shm_atime = shp->shm_atim; | |
730 | tbuf.shm_dtime = shp->shm_dtim; | |
731 | tbuf.shm_ctime = shp->shm_ctim; | |
732 | tbuf.shm_cpid = shp->shm_cprid; | |
733 | tbuf.shm_lpid = shp->shm_lprid; | |
734 | tbuf.shm_nattch = shp->shm_nattch; | |
735 | shm_unlock(shp); | |
736 | if(copy_shmid_to_user (buf, &tbuf, version)) | |
737 | err = -EFAULT; | |
738 | else | |
739 | err = result; | |
740 | goto out; | |
741 | } | |
742 | case SHM_LOCK: | |
743 | case SHM_UNLOCK: | |
744 | { | |
745 | struct file *uninitialized_var(shm_file); | |
746 | ||
747 | lru_add_drain_all(); /* drain pagevecs to lru lists */ | |
748 | ||
749 | shp = shm_lock_check(ns, shmid); | |
750 | if (IS_ERR(shp)) { | |
751 | err = PTR_ERR(shp); | |
752 | goto out; | |
753 | } | |
754 | ||
755 | audit_ipc_obj(&(shp->shm_perm)); | |
756 | ||
757 | if (!capable(CAP_IPC_LOCK)) { | |
758 | uid_t euid = current_euid(); | |
759 | err = -EPERM; | |
760 | if (euid != shp->shm_perm.uid && | |
761 | euid != shp->shm_perm.cuid) | |
762 | goto out_unlock; | |
763 | if (cmd == SHM_LOCK && | |
764 | !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur) | |
765 | goto out_unlock; | |
766 | } | |
767 | ||
768 | err = security_shm_shmctl(shp, cmd); | |
769 | if (err) | |
770 | goto out_unlock; | |
771 | ||
772 | if(cmd==SHM_LOCK) { | |
773 | struct user_struct *user = current_user(); | |
774 | if (!is_file_hugepages(shp->shm_file)) { | |
775 | err = shmem_lock(shp->shm_file, 1, user); | |
776 | if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){ | |
777 | shp->shm_perm.mode |= SHM_LOCKED; | |
778 | shp->mlock_user = user; | |
779 | } | |
780 | } | |
781 | } else if (!is_file_hugepages(shp->shm_file)) { | |
782 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
783 | shp->shm_perm.mode &= ~SHM_LOCKED; | |
784 | shp->mlock_user = NULL; | |
785 | } | |
786 | shm_unlock(shp); | |
787 | goto out; | |
788 | } | |
789 | case IPC_RMID: | |
790 | case IPC_SET: | |
791 | err = shmctl_down(ns, shmid, cmd, buf, version); | |
792 | return err; | |
793 | default: | |
794 | return -EINVAL; | |
795 | } | |
796 | ||
797 | out_unlock: | |
798 | shm_unlock(shp); | |
799 | out: | |
800 | return err; | |
801 | } | |
802 | ||
803 | /* | |
804 | * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. | |
805 | * | |
806 | * NOTE! Despite the name, this is NOT a direct system call entrypoint. The | |
807 | * "raddr" thing points to kernel space, and there has to be a wrapper around | |
808 | * this. | |
809 | */ | |
810 | long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) | |
811 | { | |
812 | struct shmid_kernel *shp; | |
813 | unsigned long addr; | |
814 | unsigned long size; | |
815 | struct file * file; | |
816 | int err; | |
817 | unsigned long flags; | |
818 | unsigned long prot; | |
819 | int acc_mode; | |
820 | unsigned long user_addr; | |
821 | struct ipc_namespace *ns; | |
822 | struct shm_file_data *sfd; | |
823 | struct path path; | |
824 | fmode_t f_mode; | |
825 | ||
826 | err = -EINVAL; | |
827 | if (shmid < 0) | |
828 | goto out; | |
829 | else if ((addr = (ulong)shmaddr)) { | |
830 | if (addr & (SHMLBA-1)) { | |
831 | if (shmflg & SHM_RND) | |
832 | addr &= ~(SHMLBA-1); /* round down */ | |
833 | else | |
834 | #ifndef __ARCH_FORCE_SHMLBA | |
835 | if (addr & ~PAGE_MASK) | |
836 | #endif | |
837 | goto out; | |
838 | } | |
839 | flags = MAP_SHARED | MAP_FIXED; | |
840 | } else { | |
841 | if ((shmflg & SHM_REMAP)) | |
842 | goto out; | |
843 | ||
844 | flags = MAP_SHARED; | |
845 | } | |
846 | ||
847 | if (shmflg & SHM_RDONLY) { | |
848 | prot = PROT_READ; | |
849 | acc_mode = S_IRUGO; | |
850 | f_mode = FMODE_READ; | |
851 | } else { | |
852 | prot = PROT_READ | PROT_WRITE; | |
853 | acc_mode = S_IRUGO | S_IWUGO; | |
854 | f_mode = FMODE_READ | FMODE_WRITE; | |
855 | } | |
856 | if (shmflg & SHM_EXEC) { | |
857 | prot |= PROT_EXEC; | |
858 | acc_mode |= S_IXUGO; | |
859 | } | |
860 | ||
861 | /* | |
862 | * We cannot rely on the fs check since SYSV IPC does have an | |
863 | * additional creator id... | |
864 | */ | |
865 | ns = current->nsproxy->ipc_ns; | |
866 | shp = shm_lock_check(ns, shmid); | |
867 | if (IS_ERR(shp)) { | |
868 | err = PTR_ERR(shp); | |
869 | goto out; | |
870 | } | |
871 | ||
872 | err = -EACCES; | |
873 | if (ipcperms(&shp->shm_perm, acc_mode)) | |
874 | goto out_unlock; | |
875 | ||
876 | err = security_shm_shmat(shp, shmaddr, shmflg); | |
877 | if (err) | |
878 | goto out_unlock; | |
879 | ||
880 | path.dentry = dget(shp->shm_file->f_path.dentry); | |
881 | path.mnt = shp->shm_file->f_path.mnt; | |
882 | shp->shm_nattch++; | |
883 | size = i_size_read(path.dentry->d_inode); | |
884 | shm_unlock(shp); | |
885 | ||
886 | err = -ENOMEM; | |
887 | sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); | |
888 | if (!sfd) | |
889 | goto out_put_dentry; | |
890 | ||
891 | file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations); | |
892 | if (!file) | |
893 | goto out_free; | |
894 | ima_shm_check(file); | |
895 | ||
896 | file->private_data = sfd; | |
897 | file->f_mapping = shp->shm_file->f_mapping; | |
898 | sfd->id = shp->shm_perm.id; | |
899 | sfd->ns = get_ipc_ns(ns); | |
900 | sfd->file = shp->shm_file; | |
901 | sfd->vm_ops = NULL; | |
902 | ||
903 | down_write(¤t->mm->mmap_sem); | |
904 | if (addr && !(shmflg & SHM_REMAP)) { | |
905 | err = -EINVAL; | |
906 | if (find_vma_intersection(current->mm, addr, addr + size)) | |
907 | goto invalid; | |
908 | /* | |
909 | * If shm segment goes below stack, make sure there is some | |
910 | * space left for the stack to grow (at least 4 pages). | |
911 | */ | |
912 | if (addr < current->mm->start_stack && | |
913 | addr > current->mm->start_stack - size - PAGE_SIZE * 5) | |
914 | goto invalid; | |
915 | } | |
916 | ||
917 | user_addr = do_mmap (file, addr, size, prot, flags, 0); | |
918 | *raddr = user_addr; | |
919 | err = 0; | |
920 | if (IS_ERR_VALUE(user_addr)) | |
921 | err = (long)user_addr; | |
922 | invalid: | |
923 | up_write(¤t->mm->mmap_sem); | |
924 | ||
925 | fput(file); | |
926 | ||
927 | out_nattch: | |
928 | down_write(&shm_ids(ns).rw_mutex); | |
929 | shp = shm_lock(ns, shmid); | |
930 | BUG_ON(IS_ERR(shp)); | |
931 | shp->shm_nattch--; | |
932 | if(shp->shm_nattch == 0 && | |
933 | shp->shm_perm.mode & SHM_DEST) | |
934 | shm_destroy(ns, shp); | |
935 | else | |
936 | shm_unlock(shp); | |
937 | up_write(&shm_ids(ns).rw_mutex); | |
938 | ||
939 | out: | |
940 | return err; | |
941 | ||
942 | out_unlock: | |
943 | shm_unlock(shp); | |
944 | goto out; | |
945 | ||
946 | out_free: | |
947 | kfree(sfd); | |
948 | out_put_dentry: | |
949 | dput(path.dentry); | |
950 | goto out_nattch; | |
951 | } | |
952 | ||
953 | SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg) | |
954 | { | |
955 | unsigned long ret; | |
956 | long err; | |
957 | ||
958 | err = do_shmat(shmid, shmaddr, shmflg, &ret); | |
959 | if (err) | |
960 | return err; | |
961 | force_successful_syscall_return(); | |
962 | return (long)ret; | |
963 | } | |
964 | ||
965 | /* | |
966 | * detach and kill segment if marked destroyed. | |
967 | * The work is done in shm_close. | |
968 | */ | |
969 | SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) | |
970 | { | |
971 | struct mm_struct *mm = current->mm; | |
972 | struct vm_area_struct *vma, *next; | |
973 | unsigned long addr = (unsigned long)shmaddr; | |
974 | loff_t size = 0; | |
975 | int retval = -EINVAL; | |
976 | ||
977 | if (addr & ~PAGE_MASK) | |
978 | return retval; | |
979 | ||
980 | down_write(&mm->mmap_sem); | |
981 | ||
982 | /* | |
983 | * This function tries to be smart and unmap shm segments that | |
984 | * were modified by partial mlock or munmap calls: | |
985 | * - It first determines the size of the shm segment that should be | |
986 | * unmapped: It searches for a vma that is backed by shm and that | |
987 | * started at address shmaddr. It records it's size and then unmaps | |
988 | * it. | |
989 | * - Then it unmaps all shm vmas that started at shmaddr and that | |
990 | * are within the initially determined size. | |
991 | * Errors from do_munmap are ignored: the function only fails if | |
992 | * it's called with invalid parameters or if it's called to unmap | |
993 | * a part of a vma. Both calls in this function are for full vmas, | |
994 | * the parameters are directly copied from the vma itself and always | |
995 | * valid - therefore do_munmap cannot fail. (famous last words?) | |
996 | */ | |
997 | /* | |
998 | * If it had been mremap()'d, the starting address would not | |
999 | * match the usual checks anyway. So assume all vma's are | |
1000 | * above the starting address given. | |
1001 | */ | |
1002 | vma = find_vma(mm, addr); | |
1003 | ||
1004 | #ifdef CONFIG_MMU | |
1005 | while (vma) { | |
1006 | next = vma->vm_next; | |
1007 | ||
1008 | /* | |
1009 | * Check if the starting address would match, i.e. it's | |
1010 | * a fragment created by mprotect() and/or munmap(), or it | |
1011 | * otherwise it starts at this address with no hassles. | |
1012 | */ | |
1013 | if ((vma->vm_ops == &shm_vm_ops) && | |
1014 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { | |
1015 | ||
1016 | ||
1017 | size = vma->vm_file->f_path.dentry->d_inode->i_size; | |
1018 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
1019 | /* | |
1020 | * We discovered the size of the shm segment, so | |
1021 | * break out of here and fall through to the next | |
1022 | * loop that uses the size information to stop | |
1023 | * searching for matching vma's. | |
1024 | */ | |
1025 | retval = 0; | |
1026 | vma = next; | |
1027 | break; | |
1028 | } | |
1029 | vma = next; | |
1030 | } | |
1031 | ||
1032 | /* | |
1033 | * We need look no further than the maximum address a fragment | |
1034 | * could possibly have landed at. Also cast things to loff_t to | |
1035 | * prevent overflows and make comparisions vs. equal-width types. | |
1036 | */ | |
1037 | size = PAGE_ALIGN(size); | |
1038 | while (vma && (loff_t)(vma->vm_end - addr) <= size) { | |
1039 | next = vma->vm_next; | |
1040 | ||
1041 | /* finding a matching vma now does not alter retval */ | |
1042 | if ((vma->vm_ops == &shm_vm_ops) && | |
1043 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) | |
1044 | ||
1045 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
1046 | vma = next; | |
1047 | } | |
1048 | ||
1049 | #else /* CONFIG_MMU */ | |
1050 | /* under NOMMU conditions, the exact address to be destroyed must be | |
1051 | * given */ | |
1052 | retval = -EINVAL; | |
1053 | if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) { | |
1054 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
1055 | retval = 0; | |
1056 | } | |
1057 | ||
1058 | #endif | |
1059 | ||
1060 | up_write(&mm->mmap_sem); | |
1061 | return retval; | |
1062 | } | |
1063 | ||
1064 | #ifdef CONFIG_PROC_FS | |
1065 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it) | |
1066 | { | |
1067 | struct shmid_kernel *shp = it; | |
1068 | ||
1069 | #if BITS_PER_LONG <= 32 | |
1070 | #define SIZE_SPEC "%10lu" | |
1071 | #else | |
1072 | #define SIZE_SPEC "%21lu" | |
1073 | #endif | |
1074 | ||
1075 | return seq_printf(s, | |
1076 | "%10d %10d %4o " SIZE_SPEC " %5u %5u " | |
1077 | "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n", | |
1078 | shp->shm_perm.key, | |
1079 | shp->shm_perm.id, | |
1080 | shp->shm_perm.mode, | |
1081 | shp->shm_segsz, | |
1082 | shp->shm_cprid, | |
1083 | shp->shm_lprid, | |
1084 | shp->shm_nattch, | |
1085 | shp->shm_perm.uid, | |
1086 | shp->shm_perm.gid, | |
1087 | shp->shm_perm.cuid, | |
1088 | shp->shm_perm.cgid, | |
1089 | shp->shm_atim, | |
1090 | shp->shm_dtim, | |
1091 | shp->shm_ctim); | |
1092 | } | |
1093 | #endif |