Commit | Line | Data |
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1da177e4 LT |
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 | * | |
073115d6 SG |
16 | * support for audit of ipc object properties and permission changes |
17 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> | |
1da177e4 LT |
18 | */ |
19 | ||
1da177e4 LT |
20 | #include <linux/slab.h> |
21 | #include <linux/mm.h> | |
22 | #include <linux/hugetlb.h> | |
23 | #include <linux/shm.h> | |
24 | #include <linux/init.h> | |
25 | #include <linux/file.h> | |
26 | #include <linux/mman.h> | |
1da177e4 LT |
27 | #include <linux/shmem_fs.h> |
28 | #include <linux/security.h> | |
29 | #include <linux/syscalls.h> | |
30 | #include <linux/audit.h> | |
c59ede7b | 31 | #include <linux/capability.h> |
7d87e14c | 32 | #include <linux/ptrace.h> |
19b4946c | 33 | #include <linux/seq_file.h> |
5f921ae9 | 34 | #include <linux/mutex.h> |
7d87e14c | 35 | |
1da177e4 LT |
36 | #include <asm/uaccess.h> |
37 | ||
38 | #include "util.h" | |
39 | ||
1da177e4 LT |
40 | static struct file_operations shm_file_operations; |
41 | static struct vm_operations_struct shm_vm_ops; | |
42 | ||
43 | static struct ipc_ids shm_ids; | |
44 | ||
45 | #define shm_lock(id) ((struct shmid_kernel*)ipc_lock(&shm_ids,id)) | |
46 | #define shm_unlock(shp) ipc_unlock(&(shp)->shm_perm) | |
47 | #define shm_get(id) ((struct shmid_kernel*)ipc_get(&shm_ids,id)) | |
48 | #define shm_buildid(id, seq) \ | |
49 | ipc_buildid(&shm_ids, id, seq) | |
50 | ||
51 | static int newseg (key_t key, int shmflg, size_t size); | |
52 | static void shm_open (struct vm_area_struct *shmd); | |
53 | static void shm_close (struct vm_area_struct *shmd); | |
54 | #ifdef CONFIG_PROC_FS | |
19b4946c | 55 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it); |
1da177e4 LT |
56 | #endif |
57 | ||
58 | size_t shm_ctlmax = SHMMAX; | |
59 | size_t shm_ctlall = SHMALL; | |
60 | int shm_ctlmni = SHMMNI; | |
61 | ||
62 | static int shm_tot; /* total number of shared memory pages */ | |
63 | ||
64 | void __init shm_init (void) | |
65 | { | |
66 | ipc_init_ids(&shm_ids, 1); | |
19b4946c MW |
67 | ipc_init_proc_interface("sysvipc/shm", |
68 | " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n", | |
69 | &shm_ids, | |
70 | sysvipc_shm_proc_show); | |
1da177e4 LT |
71 | } |
72 | ||
73 | static inline int shm_checkid(struct shmid_kernel *s, int id) | |
74 | { | |
75 | if (ipc_checkid(&shm_ids,&s->shm_perm,id)) | |
76 | return -EIDRM; | |
77 | return 0; | |
78 | } | |
79 | ||
80 | static inline struct shmid_kernel *shm_rmid(int id) | |
81 | { | |
82 | return (struct shmid_kernel *)ipc_rmid(&shm_ids,id); | |
83 | } | |
84 | ||
85 | static inline int shm_addid(struct shmid_kernel *shp) | |
86 | { | |
87 | return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni); | |
88 | } | |
89 | ||
90 | ||
91 | ||
92 | static inline void shm_inc (int id) { | |
93 | struct shmid_kernel *shp; | |
94 | ||
9ba025f1 ES |
95 | shp = shm_lock(id); |
96 | BUG_ON(!shp); | |
1da177e4 LT |
97 | shp->shm_atim = get_seconds(); |
98 | shp->shm_lprid = current->tgid; | |
99 | shp->shm_nattch++; | |
100 | shm_unlock(shp); | |
101 | } | |
102 | ||
103 | /* This is called by fork, once for every shm attach. */ | |
104 | static void shm_open (struct vm_area_struct *shmd) | |
105 | { | |
106 | shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino); | |
107 | } | |
108 | ||
109 | /* | |
110 | * shm_destroy - free the struct shmid_kernel | |
111 | * | |
112 | * @shp: struct to free | |
113 | * | |
5f921ae9 | 114 | * It has to be called with shp and shm_ids.mutex locked, |
1da177e4 LT |
115 | * but returns with shp unlocked and freed. |
116 | */ | |
117 | static void shm_destroy (struct shmid_kernel *shp) | |
118 | { | |
119 | shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
120 | shm_rmid (shp->id); | |
121 | shm_unlock(shp); | |
122 | if (!is_file_hugepages(shp->shm_file)) | |
123 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
124 | else | |
125 | user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size, | |
126 | shp->mlock_user); | |
127 | fput (shp->shm_file); | |
128 | security_shm_free(shp); | |
129 | ipc_rcu_putref(shp); | |
130 | } | |
131 | ||
132 | /* | |
133 | * remove the attach descriptor shmd. | |
134 | * free memory for segment if it is marked destroyed. | |
135 | * The descriptor has already been removed from the current->mm->mmap list | |
136 | * and will later be kfree()d. | |
137 | */ | |
138 | static void shm_close (struct vm_area_struct *shmd) | |
139 | { | |
140 | struct file * file = shmd->vm_file; | |
141 | int id = file->f_dentry->d_inode->i_ino; | |
142 | struct shmid_kernel *shp; | |
143 | ||
5f921ae9 | 144 | mutex_lock(&shm_ids.mutex); |
1da177e4 | 145 | /* remove from the list of attaches of the shm segment */ |
9ba025f1 ES |
146 | shp = shm_lock(id); |
147 | BUG_ON(!shp); | |
1da177e4 LT |
148 | shp->shm_lprid = current->tgid; |
149 | shp->shm_dtim = get_seconds(); | |
150 | shp->shm_nattch--; | |
151 | if(shp->shm_nattch == 0 && | |
b33291c0 | 152 | shp->shm_perm.mode & SHM_DEST) |
1da177e4 LT |
153 | shm_destroy (shp); |
154 | else | |
155 | shm_unlock(shp); | |
5f921ae9 | 156 | mutex_unlock(&shm_ids.mutex); |
1da177e4 LT |
157 | } |
158 | ||
159 | static int shm_mmap(struct file * file, struct vm_area_struct * vma) | |
160 | { | |
b0e15190 DH |
161 | int ret; |
162 | ||
163 | ret = shmem_mmap(file, vma); | |
164 | if (ret == 0) { | |
165 | vma->vm_ops = &shm_vm_ops; | |
b78b6af6 HD |
166 | if (!(vma->vm_flags & VM_WRITE)) |
167 | vma->vm_flags &= ~VM_MAYWRITE; | |
b0e15190 DH |
168 | shm_inc(file->f_dentry->d_inode->i_ino); |
169 | } | |
170 | ||
171 | return ret; | |
1da177e4 LT |
172 | } |
173 | ||
174 | static struct file_operations shm_file_operations = { | |
b0e15190 DH |
175 | .mmap = shm_mmap, |
176 | #ifndef CONFIG_MMU | |
177 | .get_unmapped_area = shmem_get_unmapped_area, | |
178 | #endif | |
1da177e4 LT |
179 | }; |
180 | ||
181 | static struct vm_operations_struct shm_vm_ops = { | |
182 | .open = shm_open, /* callback for a new vm-area open */ | |
183 | .close = shm_close, /* callback for when the vm-area is released */ | |
184 | .nopage = shmem_nopage, | |
6ade43fb | 185 | #if defined(CONFIG_NUMA) && defined(CONFIG_SHMEM) |
1da177e4 LT |
186 | .set_policy = shmem_set_policy, |
187 | .get_policy = shmem_get_policy, | |
188 | #endif | |
189 | }; | |
190 | ||
191 | static int newseg (key_t key, int shmflg, size_t size) | |
192 | { | |
193 | int error; | |
194 | struct shmid_kernel *shp; | |
195 | int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; | |
196 | struct file * file; | |
197 | char name[13]; | |
198 | int id; | |
199 | ||
200 | if (size < SHMMIN || size > shm_ctlmax) | |
201 | return -EINVAL; | |
202 | ||
203 | if (shm_tot + numpages >= shm_ctlall) | |
204 | return -ENOSPC; | |
205 | ||
206 | shp = ipc_rcu_alloc(sizeof(*shp)); | |
207 | if (!shp) | |
208 | return -ENOMEM; | |
209 | ||
210 | shp->shm_perm.key = key; | |
b33291c0 | 211 | shp->shm_perm.mode = (shmflg & S_IRWXUGO); |
1da177e4 LT |
212 | shp->mlock_user = NULL; |
213 | ||
214 | shp->shm_perm.security = NULL; | |
215 | error = security_shm_alloc(shp); | |
216 | if (error) { | |
217 | ipc_rcu_putref(shp); | |
218 | return error; | |
219 | } | |
220 | ||
221 | if (shmflg & SHM_HUGETLB) { | |
222 | /* hugetlb_zero_setup takes care of mlock user accounting */ | |
223 | file = hugetlb_zero_setup(size); | |
224 | shp->mlock_user = current->user; | |
225 | } else { | |
bf8f972d BP |
226 | int acctflag = VM_ACCOUNT; |
227 | /* | |
228 | * Do not allow no accounting for OVERCOMMIT_NEVER, even | |
229 | * if it's asked for. | |
230 | */ | |
231 | if ((shmflg & SHM_NORESERVE) && | |
232 | sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
233 | acctflag = 0; | |
1da177e4 | 234 | sprintf (name, "SYSV%08x", key); |
bf8f972d | 235 | file = shmem_file_setup(name, size, acctflag); |
1da177e4 LT |
236 | } |
237 | error = PTR_ERR(file); | |
238 | if (IS_ERR(file)) | |
239 | goto no_file; | |
240 | ||
241 | error = -ENOSPC; | |
242 | id = shm_addid(shp); | |
243 | if(id == -1) | |
244 | goto no_id; | |
245 | ||
246 | shp->shm_cprid = current->tgid; | |
247 | shp->shm_lprid = 0; | |
248 | shp->shm_atim = shp->shm_dtim = 0; | |
249 | shp->shm_ctim = get_seconds(); | |
250 | shp->shm_segsz = size; | |
251 | shp->shm_nattch = 0; | |
252 | shp->id = shm_buildid(id,shp->shm_perm.seq); | |
253 | shp->shm_file = file; | |
254 | file->f_dentry->d_inode->i_ino = shp->id; | |
551110a9 K |
255 | |
256 | /* Hugetlb ops would have already been assigned. */ | |
257 | if (!(shmflg & SHM_HUGETLB)) | |
1da177e4 | 258 | file->f_op = &shm_file_operations; |
551110a9 | 259 | |
1da177e4 LT |
260 | shm_tot += numpages; |
261 | shm_unlock(shp); | |
262 | return shp->id; | |
263 | ||
264 | no_id: | |
265 | fput(file); | |
266 | no_file: | |
267 | security_shm_free(shp); | |
268 | ipc_rcu_putref(shp); | |
269 | return error; | |
270 | } | |
271 | ||
272 | asmlinkage long sys_shmget (key_t key, size_t size, int shmflg) | |
273 | { | |
274 | struct shmid_kernel *shp; | |
275 | int err, id = 0; | |
276 | ||
5f921ae9 | 277 | mutex_lock(&shm_ids.mutex); |
1da177e4 LT |
278 | if (key == IPC_PRIVATE) { |
279 | err = newseg(key, shmflg, size); | |
280 | } else if ((id = ipc_findkey(&shm_ids, key)) == -1) { | |
281 | if (!(shmflg & IPC_CREAT)) | |
282 | err = -ENOENT; | |
283 | else | |
284 | err = newseg(key, shmflg, size); | |
285 | } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) { | |
286 | err = -EEXIST; | |
287 | } else { | |
288 | shp = shm_lock(id); | |
9ba025f1 | 289 | BUG_ON(shp==NULL); |
1da177e4 LT |
290 | if (shp->shm_segsz < size) |
291 | err = -EINVAL; | |
292 | else if (ipcperms(&shp->shm_perm, shmflg)) | |
293 | err = -EACCES; | |
294 | else { | |
295 | int shmid = shm_buildid(id, shp->shm_perm.seq); | |
296 | err = security_shm_associate(shp, shmflg); | |
297 | if (!err) | |
298 | err = shmid; | |
299 | } | |
300 | shm_unlock(shp); | |
301 | } | |
5f921ae9 | 302 | mutex_unlock(&shm_ids.mutex); |
1da177e4 LT |
303 | |
304 | return err; | |
305 | } | |
306 | ||
307 | static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) | |
308 | { | |
309 | switch(version) { | |
310 | case IPC_64: | |
311 | return copy_to_user(buf, in, sizeof(*in)); | |
312 | case IPC_OLD: | |
313 | { | |
314 | struct shmid_ds out; | |
315 | ||
316 | ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); | |
317 | out.shm_segsz = in->shm_segsz; | |
318 | out.shm_atime = in->shm_atime; | |
319 | out.shm_dtime = in->shm_dtime; | |
320 | out.shm_ctime = in->shm_ctime; | |
321 | out.shm_cpid = in->shm_cpid; | |
322 | out.shm_lpid = in->shm_lpid; | |
323 | out.shm_nattch = in->shm_nattch; | |
324 | ||
325 | return copy_to_user(buf, &out, sizeof(out)); | |
326 | } | |
327 | default: | |
328 | return -EINVAL; | |
329 | } | |
330 | } | |
331 | ||
332 | struct shm_setbuf { | |
333 | uid_t uid; | |
334 | gid_t gid; | |
335 | mode_t mode; | |
336 | }; | |
337 | ||
338 | static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version) | |
339 | { | |
340 | switch(version) { | |
341 | case IPC_64: | |
342 | { | |
343 | struct shmid64_ds tbuf; | |
344 | ||
345 | if (copy_from_user(&tbuf, buf, sizeof(tbuf))) | |
346 | return -EFAULT; | |
347 | ||
348 | out->uid = tbuf.shm_perm.uid; | |
349 | out->gid = tbuf.shm_perm.gid; | |
b33291c0 | 350 | out->mode = tbuf.shm_perm.mode; |
1da177e4 LT |
351 | |
352 | return 0; | |
353 | } | |
354 | case IPC_OLD: | |
355 | { | |
356 | struct shmid_ds tbuf_old; | |
357 | ||
358 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) | |
359 | return -EFAULT; | |
360 | ||
361 | out->uid = tbuf_old.shm_perm.uid; | |
362 | out->gid = tbuf_old.shm_perm.gid; | |
b33291c0 | 363 | out->mode = tbuf_old.shm_perm.mode; |
1da177e4 LT |
364 | |
365 | return 0; | |
366 | } | |
367 | default: | |
368 | return -EINVAL; | |
369 | } | |
370 | } | |
371 | ||
372 | static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) | |
373 | { | |
374 | switch(version) { | |
375 | case IPC_64: | |
376 | return copy_to_user(buf, in, sizeof(*in)); | |
377 | case IPC_OLD: | |
378 | { | |
379 | struct shminfo out; | |
380 | ||
381 | if(in->shmmax > INT_MAX) | |
382 | out.shmmax = INT_MAX; | |
383 | else | |
384 | out.shmmax = (int)in->shmmax; | |
385 | ||
386 | out.shmmin = in->shmmin; | |
387 | out.shmmni = in->shmmni; | |
388 | out.shmseg = in->shmseg; | |
389 | out.shmall = in->shmall; | |
390 | ||
391 | return copy_to_user(buf, &out, sizeof(out)); | |
392 | } | |
393 | default: | |
394 | return -EINVAL; | |
395 | } | |
396 | } | |
397 | ||
398 | static void shm_get_stat(unsigned long *rss, unsigned long *swp) | |
399 | { | |
400 | int i; | |
401 | ||
402 | *rss = 0; | |
403 | *swp = 0; | |
404 | ||
405 | for (i = 0; i <= shm_ids.max_id; i++) { | |
406 | struct shmid_kernel *shp; | |
407 | struct inode *inode; | |
408 | ||
409 | shp = shm_get(i); | |
410 | if(!shp) | |
411 | continue; | |
412 | ||
413 | inode = shp->shm_file->f_dentry->d_inode; | |
414 | ||
415 | if (is_file_hugepages(shp->shm_file)) { | |
416 | struct address_space *mapping = inode->i_mapping; | |
417 | *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages; | |
418 | } else { | |
419 | struct shmem_inode_info *info = SHMEM_I(inode); | |
420 | spin_lock(&info->lock); | |
421 | *rss += inode->i_mapping->nrpages; | |
422 | *swp += info->swapped; | |
423 | spin_unlock(&info->lock); | |
424 | } | |
425 | } | |
426 | } | |
427 | ||
428 | asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf) | |
429 | { | |
430 | struct shm_setbuf setbuf; | |
431 | struct shmid_kernel *shp; | |
432 | int err, version; | |
433 | ||
434 | if (cmd < 0 || shmid < 0) { | |
435 | err = -EINVAL; | |
436 | goto out; | |
437 | } | |
438 | ||
439 | version = ipc_parse_version(&cmd); | |
440 | ||
441 | switch (cmd) { /* replace with proc interface ? */ | |
442 | case IPC_INFO: | |
443 | { | |
444 | struct shminfo64 shminfo; | |
445 | ||
446 | err = security_shm_shmctl(NULL, cmd); | |
447 | if (err) | |
448 | return err; | |
449 | ||
450 | memset(&shminfo,0,sizeof(shminfo)); | |
451 | shminfo.shmmni = shminfo.shmseg = shm_ctlmni; | |
452 | shminfo.shmmax = shm_ctlmax; | |
453 | shminfo.shmall = shm_ctlall; | |
454 | ||
455 | shminfo.shmmin = SHMMIN; | |
456 | if(copy_shminfo_to_user (buf, &shminfo, version)) | |
457 | return -EFAULT; | |
458 | /* reading a integer is always atomic */ | |
459 | err= shm_ids.max_id; | |
460 | if(err<0) | |
461 | err = 0; | |
462 | goto out; | |
463 | } | |
464 | case SHM_INFO: | |
465 | { | |
466 | struct shm_info shm_info; | |
467 | ||
468 | err = security_shm_shmctl(NULL, cmd); | |
469 | if (err) | |
470 | return err; | |
471 | ||
472 | memset(&shm_info,0,sizeof(shm_info)); | |
5f921ae9 | 473 | mutex_lock(&shm_ids.mutex); |
1da177e4 LT |
474 | shm_info.used_ids = shm_ids.in_use; |
475 | shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp); | |
476 | shm_info.shm_tot = shm_tot; | |
477 | shm_info.swap_attempts = 0; | |
478 | shm_info.swap_successes = 0; | |
479 | err = shm_ids.max_id; | |
5f921ae9 | 480 | mutex_unlock(&shm_ids.mutex); |
1da177e4 LT |
481 | if(copy_to_user (buf, &shm_info, sizeof(shm_info))) { |
482 | err = -EFAULT; | |
483 | goto out; | |
484 | } | |
485 | ||
486 | err = err < 0 ? 0 : err; | |
487 | goto out; | |
488 | } | |
489 | case SHM_STAT: | |
490 | case IPC_STAT: | |
491 | { | |
492 | struct shmid64_ds tbuf; | |
493 | int result; | |
494 | memset(&tbuf, 0, sizeof(tbuf)); | |
495 | shp = shm_lock(shmid); | |
496 | if(shp==NULL) { | |
497 | err = -EINVAL; | |
498 | goto out; | |
499 | } else if(cmd==SHM_STAT) { | |
500 | err = -EINVAL; | |
501 | if (shmid > shm_ids.max_id) | |
502 | goto out_unlock; | |
503 | result = shm_buildid(shmid, shp->shm_perm.seq); | |
504 | } else { | |
505 | err = shm_checkid(shp,shmid); | |
506 | if(err) | |
507 | goto out_unlock; | |
508 | result = 0; | |
509 | } | |
510 | err=-EACCES; | |
511 | if (ipcperms (&shp->shm_perm, S_IRUGO)) | |
512 | goto out_unlock; | |
513 | err = security_shm_shmctl(shp, cmd); | |
514 | if (err) | |
515 | goto out_unlock; | |
516 | kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); | |
517 | tbuf.shm_segsz = shp->shm_segsz; | |
518 | tbuf.shm_atime = shp->shm_atim; | |
519 | tbuf.shm_dtime = shp->shm_dtim; | |
520 | tbuf.shm_ctime = shp->shm_ctim; | |
521 | tbuf.shm_cpid = shp->shm_cprid; | |
522 | tbuf.shm_lpid = shp->shm_lprid; | |
523 | if (!is_file_hugepages(shp->shm_file)) | |
524 | tbuf.shm_nattch = shp->shm_nattch; | |
525 | else | |
526 | tbuf.shm_nattch = file_count(shp->shm_file) - 1; | |
527 | shm_unlock(shp); | |
528 | if(copy_shmid_to_user (buf, &tbuf, version)) | |
529 | err = -EFAULT; | |
530 | else | |
531 | err = result; | |
532 | goto out; | |
533 | } | |
534 | case SHM_LOCK: | |
535 | case SHM_UNLOCK: | |
536 | { | |
537 | shp = shm_lock(shmid); | |
538 | if(shp==NULL) { | |
539 | err = -EINVAL; | |
540 | goto out; | |
541 | } | |
542 | err = shm_checkid(shp,shmid); | |
543 | if(err) | |
544 | goto out_unlock; | |
545 | ||
073115d6 SG |
546 | err = audit_ipc_obj(&(shp->shm_perm)); |
547 | if (err) | |
548 | goto out_unlock; | |
549 | ||
1da177e4 LT |
550 | if (!capable(CAP_IPC_LOCK)) { |
551 | err = -EPERM; | |
552 | if (current->euid != shp->shm_perm.uid && | |
553 | current->euid != shp->shm_perm.cuid) | |
554 | goto out_unlock; | |
555 | if (cmd == SHM_LOCK && | |
556 | !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur) | |
557 | goto out_unlock; | |
558 | } | |
559 | ||
560 | err = security_shm_shmctl(shp, cmd); | |
561 | if (err) | |
562 | goto out_unlock; | |
563 | ||
564 | if(cmd==SHM_LOCK) { | |
565 | struct user_struct * user = current->user; | |
566 | if (!is_file_hugepages(shp->shm_file)) { | |
567 | err = shmem_lock(shp->shm_file, 1, user); | |
568 | if (!err) { | |
b33291c0 | 569 | shp->shm_perm.mode |= SHM_LOCKED; |
1da177e4 LT |
570 | shp->mlock_user = user; |
571 | } | |
572 | } | |
573 | } else if (!is_file_hugepages(shp->shm_file)) { | |
574 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
b33291c0 | 575 | shp->shm_perm.mode &= ~SHM_LOCKED; |
1da177e4 LT |
576 | shp->mlock_user = NULL; |
577 | } | |
578 | shm_unlock(shp); | |
579 | goto out; | |
580 | } | |
581 | case IPC_RMID: | |
582 | { | |
583 | /* | |
584 | * We cannot simply remove the file. The SVID states | |
585 | * that the block remains until the last person | |
586 | * detaches from it, then is deleted. A shmat() on | |
587 | * an RMID segment is legal in older Linux and if | |
588 | * we change it apps break... | |
589 | * | |
590 | * Instead we set a destroyed flag, and then blow | |
591 | * the name away when the usage hits zero. | |
592 | */ | |
5f921ae9 | 593 | mutex_lock(&shm_ids.mutex); |
1da177e4 LT |
594 | shp = shm_lock(shmid); |
595 | err = -EINVAL; | |
596 | if (shp == NULL) | |
597 | goto out_up; | |
598 | err = shm_checkid(shp, shmid); | |
599 | if(err) | |
600 | goto out_unlock_up; | |
601 | ||
073115d6 SG |
602 | err = audit_ipc_obj(&(shp->shm_perm)); |
603 | if (err) | |
604 | goto out_unlock_up; | |
605 | ||
1da177e4 LT |
606 | if (current->euid != shp->shm_perm.uid && |
607 | current->euid != shp->shm_perm.cuid && | |
608 | !capable(CAP_SYS_ADMIN)) { | |
609 | err=-EPERM; | |
610 | goto out_unlock_up; | |
611 | } | |
612 | ||
613 | err = security_shm_shmctl(shp, cmd); | |
614 | if (err) | |
615 | goto out_unlock_up; | |
616 | ||
617 | if (shp->shm_nattch){ | |
b33291c0 | 618 | shp->shm_perm.mode |= SHM_DEST; |
1da177e4 LT |
619 | /* Do not find it any more */ |
620 | shp->shm_perm.key = IPC_PRIVATE; | |
621 | shm_unlock(shp); | |
622 | } else | |
623 | shm_destroy (shp); | |
5f921ae9 | 624 | mutex_unlock(&shm_ids.mutex); |
1da177e4 LT |
625 | goto out; |
626 | } | |
627 | ||
628 | case IPC_SET: | |
629 | { | |
630 | if (copy_shmid_from_user (&setbuf, buf, version)) { | |
631 | err = -EFAULT; | |
632 | goto out; | |
633 | } | |
5f921ae9 | 634 | mutex_lock(&shm_ids.mutex); |
1da177e4 LT |
635 | shp = shm_lock(shmid); |
636 | err=-EINVAL; | |
637 | if(shp==NULL) | |
638 | goto out_up; | |
639 | err = shm_checkid(shp,shmid); | |
640 | if(err) | |
641 | goto out_unlock_up; | |
073115d6 SG |
642 | err = audit_ipc_obj(&(shp->shm_perm)); |
643 | if (err) | |
644 | goto out_unlock_up; | |
ac03221a | 645 | err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode); |
073115d6 SG |
646 | if (err) |
647 | goto out_unlock_up; | |
1da177e4 LT |
648 | err=-EPERM; |
649 | if (current->euid != shp->shm_perm.uid && | |
650 | current->euid != shp->shm_perm.cuid && | |
651 | !capable(CAP_SYS_ADMIN)) { | |
652 | goto out_unlock_up; | |
653 | } | |
654 | ||
655 | err = security_shm_shmctl(shp, cmd); | |
656 | if (err) | |
657 | goto out_unlock_up; | |
658 | ||
659 | shp->shm_perm.uid = setbuf.uid; | |
660 | shp->shm_perm.gid = setbuf.gid; | |
b33291c0 | 661 | shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO) |
1da177e4 LT |
662 | | (setbuf.mode & S_IRWXUGO); |
663 | shp->shm_ctim = get_seconds(); | |
664 | break; | |
665 | } | |
666 | ||
667 | default: | |
668 | err = -EINVAL; | |
669 | goto out; | |
670 | } | |
671 | ||
672 | err = 0; | |
673 | out_unlock_up: | |
674 | shm_unlock(shp); | |
675 | out_up: | |
5f921ae9 | 676 | mutex_unlock(&shm_ids.mutex); |
1da177e4 LT |
677 | goto out; |
678 | out_unlock: | |
679 | shm_unlock(shp); | |
680 | out: | |
681 | return err; | |
682 | } | |
683 | ||
684 | /* | |
685 | * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. | |
686 | * | |
687 | * NOTE! Despite the name, this is NOT a direct system call entrypoint. The | |
688 | * "raddr" thing points to kernel space, and there has to be a wrapper around | |
689 | * this. | |
690 | */ | |
691 | long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) | |
692 | { | |
693 | struct shmid_kernel *shp; | |
694 | unsigned long addr; | |
695 | unsigned long size; | |
696 | struct file * file; | |
697 | int err; | |
698 | unsigned long flags; | |
699 | unsigned long prot; | |
1da177e4 LT |
700 | int acc_mode; |
701 | void *user_addr; | |
702 | ||
703 | if (shmid < 0) { | |
704 | err = -EINVAL; | |
705 | goto out; | |
706 | } else if ((addr = (ulong)shmaddr)) { | |
707 | if (addr & (SHMLBA-1)) { | |
708 | if (shmflg & SHM_RND) | |
709 | addr &= ~(SHMLBA-1); /* round down */ | |
710 | else | |
711 | #ifndef __ARCH_FORCE_SHMLBA | |
712 | if (addr & ~PAGE_MASK) | |
713 | #endif | |
714 | return -EINVAL; | |
715 | } | |
716 | flags = MAP_SHARED | MAP_FIXED; | |
717 | } else { | |
718 | if ((shmflg & SHM_REMAP)) | |
719 | return -EINVAL; | |
720 | ||
721 | flags = MAP_SHARED; | |
722 | } | |
723 | ||
724 | if (shmflg & SHM_RDONLY) { | |
725 | prot = PROT_READ; | |
1da177e4 LT |
726 | acc_mode = S_IRUGO; |
727 | } else { | |
728 | prot = PROT_READ | PROT_WRITE; | |
1da177e4 LT |
729 | acc_mode = S_IRUGO | S_IWUGO; |
730 | } | |
731 | if (shmflg & SHM_EXEC) { | |
732 | prot |= PROT_EXEC; | |
733 | acc_mode |= S_IXUGO; | |
734 | } | |
735 | ||
736 | /* | |
737 | * We cannot rely on the fs check since SYSV IPC does have an | |
738 | * additional creator id... | |
739 | */ | |
740 | shp = shm_lock(shmid); | |
741 | if(shp == NULL) { | |
742 | err = -EINVAL; | |
743 | goto out; | |
744 | } | |
745 | err = shm_checkid(shp,shmid); | |
746 | if (err) { | |
747 | shm_unlock(shp); | |
748 | goto out; | |
749 | } | |
750 | if (ipcperms(&shp->shm_perm, acc_mode)) { | |
751 | shm_unlock(shp); | |
752 | err = -EACCES; | |
753 | goto out; | |
754 | } | |
755 | ||
756 | err = security_shm_shmat(shp, shmaddr, shmflg); | |
757 | if (err) { | |
758 | shm_unlock(shp); | |
759 | return err; | |
760 | } | |
761 | ||
762 | file = shp->shm_file; | |
763 | size = i_size_read(file->f_dentry->d_inode); | |
764 | shp->shm_nattch++; | |
765 | shm_unlock(shp); | |
766 | ||
767 | down_write(¤t->mm->mmap_sem); | |
768 | if (addr && !(shmflg & SHM_REMAP)) { | |
769 | user_addr = ERR_PTR(-EINVAL); | |
770 | if (find_vma_intersection(current->mm, addr, addr + size)) | |
771 | goto invalid; | |
772 | /* | |
773 | * If shm segment goes below stack, make sure there is some | |
774 | * space left for the stack to grow (at least 4 pages). | |
775 | */ | |
776 | if (addr < current->mm->start_stack && | |
777 | addr > current->mm->start_stack - size - PAGE_SIZE * 5) | |
778 | goto invalid; | |
779 | } | |
780 | ||
781 | user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0); | |
782 | ||
783 | invalid: | |
784 | up_write(¤t->mm->mmap_sem); | |
785 | ||
5f921ae9 | 786 | mutex_lock(&shm_ids.mutex); |
9ba025f1 ES |
787 | shp = shm_lock(shmid); |
788 | BUG_ON(!shp); | |
1da177e4 LT |
789 | shp->shm_nattch--; |
790 | if(shp->shm_nattch == 0 && | |
b33291c0 | 791 | shp->shm_perm.mode & SHM_DEST) |
1da177e4 LT |
792 | shm_destroy (shp); |
793 | else | |
794 | shm_unlock(shp); | |
5f921ae9 | 795 | mutex_unlock(&shm_ids.mutex); |
1da177e4 LT |
796 | |
797 | *raddr = (unsigned long) user_addr; | |
798 | err = 0; | |
799 | if (IS_ERR(user_addr)) | |
800 | err = PTR_ERR(user_addr); | |
801 | out: | |
802 | return err; | |
803 | } | |
804 | ||
7d87e14c SR |
805 | asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg) |
806 | { | |
807 | unsigned long ret; | |
808 | long err; | |
809 | ||
810 | err = do_shmat(shmid, shmaddr, shmflg, &ret); | |
811 | if (err) | |
812 | return err; | |
813 | force_successful_syscall_return(); | |
814 | return (long)ret; | |
815 | } | |
816 | ||
1da177e4 LT |
817 | /* |
818 | * detach and kill segment if marked destroyed. | |
819 | * The work is done in shm_close. | |
820 | */ | |
821 | asmlinkage long sys_shmdt(char __user *shmaddr) | |
822 | { | |
823 | struct mm_struct *mm = current->mm; | |
824 | struct vm_area_struct *vma, *next; | |
825 | unsigned long addr = (unsigned long)shmaddr; | |
826 | loff_t size = 0; | |
827 | int retval = -EINVAL; | |
828 | ||
df1e2fb5 HD |
829 | if (addr & ~PAGE_MASK) |
830 | return retval; | |
831 | ||
1da177e4 LT |
832 | down_write(&mm->mmap_sem); |
833 | ||
834 | /* | |
835 | * This function tries to be smart and unmap shm segments that | |
836 | * were modified by partial mlock or munmap calls: | |
837 | * - It first determines the size of the shm segment that should be | |
838 | * unmapped: It searches for a vma that is backed by shm and that | |
839 | * started at address shmaddr. It records it's size and then unmaps | |
840 | * it. | |
841 | * - Then it unmaps all shm vmas that started at shmaddr and that | |
842 | * are within the initially determined size. | |
843 | * Errors from do_munmap are ignored: the function only fails if | |
844 | * it's called with invalid parameters or if it's called to unmap | |
845 | * a part of a vma. Both calls in this function are for full vmas, | |
846 | * the parameters are directly copied from the vma itself and always | |
847 | * valid - therefore do_munmap cannot fail. (famous last words?) | |
848 | */ | |
849 | /* | |
850 | * If it had been mremap()'d, the starting address would not | |
851 | * match the usual checks anyway. So assume all vma's are | |
852 | * above the starting address given. | |
853 | */ | |
854 | vma = find_vma(mm, addr); | |
855 | ||
856 | while (vma) { | |
857 | next = vma->vm_next; | |
858 | ||
859 | /* | |
860 | * Check if the starting address would match, i.e. it's | |
861 | * a fragment created by mprotect() and/or munmap(), or it | |
862 | * otherwise it starts at this address with no hassles. | |
863 | */ | |
864 | if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) && | |
865 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { | |
866 | ||
867 | ||
868 | size = vma->vm_file->f_dentry->d_inode->i_size; | |
869 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
870 | /* | |
871 | * We discovered the size of the shm segment, so | |
872 | * break out of here and fall through to the next | |
873 | * loop that uses the size information to stop | |
874 | * searching for matching vma's. | |
875 | */ | |
876 | retval = 0; | |
877 | vma = next; | |
878 | break; | |
879 | } | |
880 | vma = next; | |
881 | } | |
882 | ||
883 | /* | |
884 | * We need look no further than the maximum address a fragment | |
885 | * could possibly have landed at. Also cast things to loff_t to | |
886 | * prevent overflows and make comparisions vs. equal-width types. | |
887 | */ | |
8e36709d | 888 | size = PAGE_ALIGN(size); |
1da177e4 LT |
889 | while (vma && (loff_t)(vma->vm_end - addr) <= size) { |
890 | next = vma->vm_next; | |
891 | ||
892 | /* finding a matching vma now does not alter retval */ | |
893 | if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) && | |
894 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) | |
895 | ||
896 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
897 | vma = next; | |
898 | } | |
899 | ||
900 | up_write(&mm->mmap_sem); | |
901 | return retval; | |
902 | } | |
903 | ||
904 | #ifdef CONFIG_PROC_FS | |
19b4946c | 905 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it) |
1da177e4 | 906 | { |
19b4946c MW |
907 | struct shmid_kernel *shp = it; |
908 | char *format; | |
1da177e4 | 909 | |
1da177e4 LT |
910 | #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" |
911 | #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" | |
1da177e4 | 912 | |
19b4946c MW |
913 | if (sizeof(size_t) <= sizeof(int)) |
914 | format = SMALL_STRING; | |
915 | else | |
916 | format = BIG_STRING; | |
917 | return seq_printf(s, format, | |
918 | shp->shm_perm.key, | |
919 | shp->id, | |
b33291c0 | 920 | shp->shm_perm.mode, |
19b4946c MW |
921 | shp->shm_segsz, |
922 | shp->shm_cprid, | |
923 | shp->shm_lprid, | |
924 | is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch, | |
925 | shp->shm_perm.uid, | |
926 | shp->shm_perm.gid, | |
927 | shp->shm_perm.cuid, | |
928 | shp->shm_perm.cgid, | |
929 | shp->shm_atim, | |
930 | shp->shm_dtim, | |
931 | shp->shm_ctim); | |
1da177e4 LT |
932 | } |
933 | #endif |