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1 | // SPDX-License-Identifier: GPL-2.0-only | |
2 | /* | |
3 | * linux/fs/open.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | */ | |
7 | ||
8 | #include <linux/string.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/file.h> | |
11 | #include <linux/fdtable.h> | |
12 | #include <linux/fsnotify.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/tty.h> | |
15 | #include <linux/namei.h> | |
16 | #include <linux/backing-dev.h> | |
17 | #include <linux/capability.h> | |
18 | #include <linux/securebits.h> | |
19 | #include <linux/security.h> | |
20 | #include <linux/mount.h> | |
21 | #include <linux/fcntl.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/uaccess.h> | |
24 | #include <linux/fs.h> | |
25 | #include <linux/personality.h> | |
26 | #include <linux/pagemap.h> | |
27 | #include <linux/syscalls.h> | |
28 | #include <linux/rcupdate.h> | |
29 | #include <linux/audit.h> | |
30 | #include <linux/falloc.h> | |
31 | #include <linux/fs_struct.h> | |
32 | #include <linux/ima.h> | |
33 | #include <linux/dnotify.h> | |
34 | #include <linux/compat.h> | |
35 | ||
36 | #include "internal.h" | |
37 | ||
38 | int do_truncate(struct user_namespace *mnt_userns, struct dentry *dentry, | |
39 | loff_t length, unsigned int time_attrs, struct file *filp) | |
40 | { | |
41 | int ret; | |
42 | struct iattr newattrs; | |
43 | ||
44 | /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ | |
45 | if (length < 0) | |
46 | return -EINVAL; | |
47 | ||
48 | newattrs.ia_size = length; | |
49 | newattrs.ia_valid = ATTR_SIZE | time_attrs; | |
50 | if (filp) { | |
51 | newattrs.ia_file = filp; | |
52 | newattrs.ia_valid |= ATTR_FILE; | |
53 | } | |
54 | ||
55 | /* Remove suid, sgid, and file capabilities on truncate too */ | |
56 | ret = dentry_needs_remove_privs(dentry); | |
57 | if (ret < 0) | |
58 | return ret; | |
59 | if (ret) | |
60 | newattrs.ia_valid |= ret | ATTR_FORCE; | |
61 | ||
62 | inode_lock(dentry->d_inode); | |
63 | /* Note any delegations or leases have already been broken: */ | |
64 | ret = notify_change(mnt_userns, dentry, &newattrs, NULL); | |
65 | inode_unlock(dentry->d_inode); | |
66 | return ret; | |
67 | } | |
68 | ||
69 | long vfs_truncate(const struct path *path, loff_t length) | |
70 | { | |
71 | struct user_namespace *mnt_userns; | |
72 | struct inode *inode; | |
73 | long error; | |
74 | ||
75 | inode = path->dentry->d_inode; | |
76 | ||
77 | /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ | |
78 | if (S_ISDIR(inode->i_mode)) | |
79 | return -EISDIR; | |
80 | if (!S_ISREG(inode->i_mode)) | |
81 | return -EINVAL; | |
82 | ||
83 | error = mnt_want_write(path->mnt); | |
84 | if (error) | |
85 | goto out; | |
86 | ||
87 | mnt_userns = mnt_user_ns(path->mnt); | |
88 | error = inode_permission(mnt_userns, inode, MAY_WRITE); | |
89 | if (error) | |
90 | goto mnt_drop_write_and_out; | |
91 | ||
92 | error = -EPERM; | |
93 | if (IS_APPEND(inode)) | |
94 | goto mnt_drop_write_and_out; | |
95 | ||
96 | error = get_write_access(inode); | |
97 | if (error) | |
98 | goto mnt_drop_write_and_out; | |
99 | ||
100 | /* | |
101 | * Make sure that there are no leases. get_write_access() protects | |
102 | * against the truncate racing with a lease-granting setlease(). | |
103 | */ | |
104 | error = break_lease(inode, O_WRONLY); | |
105 | if (error) | |
106 | goto put_write_and_out; | |
107 | ||
108 | error = locks_verify_truncate(inode, NULL, length); | |
109 | if (!error) | |
110 | error = security_path_truncate(path); | |
111 | if (!error) | |
112 | error = do_truncate(mnt_userns, path->dentry, length, 0, NULL); | |
113 | ||
114 | put_write_and_out: | |
115 | put_write_access(inode); | |
116 | mnt_drop_write_and_out: | |
117 | mnt_drop_write(path->mnt); | |
118 | out: | |
119 | return error; | |
120 | } | |
121 | EXPORT_SYMBOL_GPL(vfs_truncate); | |
122 | ||
123 | long do_sys_truncate(const char __user *pathname, loff_t length) | |
124 | { | |
125 | unsigned int lookup_flags = LOOKUP_FOLLOW; | |
126 | struct path path; | |
127 | int error; | |
128 | ||
129 | if (length < 0) /* sorry, but loff_t says... */ | |
130 | return -EINVAL; | |
131 | ||
132 | retry: | |
133 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
134 | if (!error) { | |
135 | error = vfs_truncate(&path, length); | |
136 | path_put(&path); | |
137 | } | |
138 | if (retry_estale(error, lookup_flags)) { | |
139 | lookup_flags |= LOOKUP_REVAL; | |
140 | goto retry; | |
141 | } | |
142 | return error; | |
143 | } | |
144 | ||
145 | SYSCALL_DEFINE2(truncate, const char __user *, path, long, length) | |
146 | { | |
147 | return do_sys_truncate(path, length); | |
148 | } | |
149 | ||
150 | #ifdef CONFIG_COMPAT | |
151 | COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length) | |
152 | { | |
153 | return do_sys_truncate(path, length); | |
154 | } | |
155 | #endif | |
156 | ||
157 | long do_sys_ftruncate(unsigned int fd, loff_t length, int small) | |
158 | { | |
159 | struct inode *inode; | |
160 | struct dentry *dentry; | |
161 | struct fd f; | |
162 | int error; | |
163 | ||
164 | error = -EINVAL; | |
165 | if (length < 0) | |
166 | goto out; | |
167 | error = -EBADF; | |
168 | f = fdget(fd); | |
169 | if (!f.file) | |
170 | goto out; | |
171 | ||
172 | /* explicitly opened as large or we are on 64-bit box */ | |
173 | if (f.file->f_flags & O_LARGEFILE) | |
174 | small = 0; | |
175 | ||
176 | dentry = f.file->f_path.dentry; | |
177 | inode = dentry->d_inode; | |
178 | error = -EINVAL; | |
179 | if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE)) | |
180 | goto out_putf; | |
181 | ||
182 | error = -EINVAL; | |
183 | /* Cannot ftruncate over 2^31 bytes without large file support */ | |
184 | if (small && length > MAX_NON_LFS) | |
185 | goto out_putf; | |
186 | ||
187 | error = -EPERM; | |
188 | /* Check IS_APPEND on real upper inode */ | |
189 | if (IS_APPEND(file_inode(f.file))) | |
190 | goto out_putf; | |
191 | sb_start_write(inode->i_sb); | |
192 | error = locks_verify_truncate(inode, f.file, length); | |
193 | if (!error) | |
194 | error = security_path_truncate(&f.file->f_path); | |
195 | if (!error) | |
196 | error = do_truncate(file_mnt_user_ns(f.file), dentry, length, | |
197 | ATTR_MTIME | ATTR_CTIME, f.file); | |
198 | sb_end_write(inode->i_sb); | |
199 | out_putf: | |
200 | fdput(f); | |
201 | out: | |
202 | return error; | |
203 | } | |
204 | ||
205 | SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length) | |
206 | { | |
207 | return do_sys_ftruncate(fd, length, 1); | |
208 | } | |
209 | ||
210 | #ifdef CONFIG_COMPAT | |
211 | COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length) | |
212 | { | |
213 | return do_sys_ftruncate(fd, length, 1); | |
214 | } | |
215 | #endif | |
216 | ||
217 | /* LFS versions of truncate are only needed on 32 bit machines */ | |
218 | #if BITS_PER_LONG == 32 | |
219 | SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length) | |
220 | { | |
221 | return do_sys_truncate(path, length); | |
222 | } | |
223 | ||
224 | SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length) | |
225 | { | |
226 | return do_sys_ftruncate(fd, length, 0); | |
227 | } | |
228 | #endif /* BITS_PER_LONG == 32 */ | |
229 | ||
230 | ||
231 | int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) | |
232 | { | |
233 | struct inode *inode = file_inode(file); | |
234 | long ret; | |
235 | ||
236 | if (offset < 0 || len <= 0) | |
237 | return -EINVAL; | |
238 | ||
239 | /* Return error if mode is not supported */ | |
240 | if (mode & ~FALLOC_FL_SUPPORTED_MASK) | |
241 | return -EOPNOTSUPP; | |
242 | ||
243 | /* Punch hole and zero range are mutually exclusive */ | |
244 | if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) == | |
245 | (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) | |
246 | return -EOPNOTSUPP; | |
247 | ||
248 | /* Punch hole must have keep size set */ | |
249 | if ((mode & FALLOC_FL_PUNCH_HOLE) && | |
250 | !(mode & FALLOC_FL_KEEP_SIZE)) | |
251 | return -EOPNOTSUPP; | |
252 | ||
253 | /* Collapse range should only be used exclusively. */ | |
254 | if ((mode & FALLOC_FL_COLLAPSE_RANGE) && | |
255 | (mode & ~FALLOC_FL_COLLAPSE_RANGE)) | |
256 | return -EINVAL; | |
257 | ||
258 | /* Insert range should only be used exclusively. */ | |
259 | if ((mode & FALLOC_FL_INSERT_RANGE) && | |
260 | (mode & ~FALLOC_FL_INSERT_RANGE)) | |
261 | return -EINVAL; | |
262 | ||
263 | /* Unshare range should only be used with allocate mode. */ | |
264 | if ((mode & FALLOC_FL_UNSHARE_RANGE) && | |
265 | (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE))) | |
266 | return -EINVAL; | |
267 | ||
268 | if (!(file->f_mode & FMODE_WRITE)) | |
269 | return -EBADF; | |
270 | ||
271 | /* | |
272 | * We can only allow pure fallocate on append only files | |
273 | */ | |
274 | if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode)) | |
275 | return -EPERM; | |
276 | ||
277 | if (IS_IMMUTABLE(inode)) | |
278 | return -EPERM; | |
279 | ||
280 | /* | |
281 | * We cannot allow any fallocate operation on an active swapfile | |
282 | */ | |
283 | if (IS_SWAPFILE(inode)) | |
284 | return -ETXTBSY; | |
285 | ||
286 | /* | |
287 | * Revalidate the write permissions, in case security policy has | |
288 | * changed since the files were opened. | |
289 | */ | |
290 | ret = security_file_permission(file, MAY_WRITE); | |
291 | if (ret) | |
292 | return ret; | |
293 | ||
294 | if (S_ISFIFO(inode->i_mode)) | |
295 | return -ESPIPE; | |
296 | ||
297 | if (S_ISDIR(inode->i_mode)) | |
298 | return -EISDIR; | |
299 | ||
300 | if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode)) | |
301 | return -ENODEV; | |
302 | ||
303 | /* Check for wrap through zero too */ | |
304 | if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0)) | |
305 | return -EFBIG; | |
306 | ||
307 | if (!file->f_op->fallocate) | |
308 | return -EOPNOTSUPP; | |
309 | ||
310 | file_start_write(file); | |
311 | ret = file->f_op->fallocate(file, mode, offset, len); | |
312 | ||
313 | /* | |
314 | * Create inotify and fanotify events. | |
315 | * | |
316 | * To keep the logic simple always create events if fallocate succeeds. | |
317 | * This implies that events are even created if the file size remains | |
318 | * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE. | |
319 | */ | |
320 | if (ret == 0) | |
321 | fsnotify_modify(file); | |
322 | ||
323 | file_end_write(file); | |
324 | return ret; | |
325 | } | |
326 | EXPORT_SYMBOL_GPL(vfs_fallocate); | |
327 | ||
328 | int ksys_fallocate(int fd, int mode, loff_t offset, loff_t len) | |
329 | { | |
330 | struct fd f = fdget(fd); | |
331 | int error = -EBADF; | |
332 | ||
333 | if (f.file) { | |
334 | error = vfs_fallocate(f.file, mode, offset, len); | |
335 | fdput(f); | |
336 | } | |
337 | return error; | |
338 | } | |
339 | ||
340 | SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len) | |
341 | { | |
342 | return ksys_fallocate(fd, mode, offset, len); | |
343 | } | |
344 | ||
345 | /* | |
346 | * access() needs to use the real uid/gid, not the effective uid/gid. | |
347 | * We do this by temporarily clearing all FS-related capabilities and | |
348 | * switching the fsuid/fsgid around to the real ones. | |
349 | */ | |
350 | static const struct cred *access_override_creds(void) | |
351 | { | |
352 | const struct cred *old_cred; | |
353 | struct cred *override_cred; | |
354 | ||
355 | override_cred = prepare_creds(); | |
356 | if (!override_cred) | |
357 | return NULL; | |
358 | ||
359 | override_cred->fsuid = override_cred->uid; | |
360 | override_cred->fsgid = override_cred->gid; | |
361 | ||
362 | if (!issecure(SECURE_NO_SETUID_FIXUP)) { | |
363 | /* Clear the capabilities if we switch to a non-root user */ | |
364 | kuid_t root_uid = make_kuid(override_cred->user_ns, 0); | |
365 | if (!uid_eq(override_cred->uid, root_uid)) | |
366 | cap_clear(override_cred->cap_effective); | |
367 | else | |
368 | override_cred->cap_effective = | |
369 | override_cred->cap_permitted; | |
370 | } | |
371 | ||
372 | /* | |
373 | * The new set of credentials can *only* be used in | |
374 | * task-synchronous circumstances, and does not need | |
375 | * RCU freeing, unless somebody then takes a separate | |
376 | * reference to it. | |
377 | * | |
378 | * NOTE! This is _only_ true because this credential | |
379 | * is used purely for override_creds() that installs | |
380 | * it as the subjective cred. Other threads will be | |
381 | * accessing ->real_cred, not the subjective cred. | |
382 | * | |
383 | * If somebody _does_ make a copy of this (using the | |
384 | * 'get_current_cred()' function), that will clear the | |
385 | * non_rcu field, because now that other user may be | |
386 | * expecting RCU freeing. But normal thread-synchronous | |
387 | * cred accesses will keep things non-RCY. | |
388 | */ | |
389 | override_cred->non_rcu = 1; | |
390 | ||
391 | old_cred = override_creds(override_cred); | |
392 | ||
393 | /* override_cred() gets its own ref */ | |
394 | put_cred(override_cred); | |
395 | ||
396 | return old_cred; | |
397 | } | |
398 | ||
399 | static long do_faccessat(int dfd, const char __user *filename, int mode, int flags) | |
400 | { | |
401 | struct path path; | |
402 | struct inode *inode; | |
403 | int res; | |
404 | unsigned int lookup_flags = LOOKUP_FOLLOW; | |
405 | const struct cred *old_cred = NULL; | |
406 | ||
407 | if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ | |
408 | return -EINVAL; | |
409 | ||
410 | if (flags & ~(AT_EACCESS | AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) | |
411 | return -EINVAL; | |
412 | ||
413 | if (flags & AT_SYMLINK_NOFOLLOW) | |
414 | lookup_flags &= ~LOOKUP_FOLLOW; | |
415 | if (flags & AT_EMPTY_PATH) | |
416 | lookup_flags |= LOOKUP_EMPTY; | |
417 | ||
418 | if (!(flags & AT_EACCESS)) { | |
419 | old_cred = access_override_creds(); | |
420 | if (!old_cred) | |
421 | return -ENOMEM; | |
422 | } | |
423 | ||
424 | retry: | |
425 | res = user_path_at(dfd, filename, lookup_flags, &path); | |
426 | if (res) | |
427 | goto out; | |
428 | ||
429 | inode = d_backing_inode(path.dentry); | |
430 | ||
431 | if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) { | |
432 | /* | |
433 | * MAY_EXEC on regular files is denied if the fs is mounted | |
434 | * with the "noexec" flag. | |
435 | */ | |
436 | res = -EACCES; | |
437 | if (path_noexec(&path)) | |
438 | goto out_path_release; | |
439 | } | |
440 | ||
441 | res = inode_permission(mnt_user_ns(path.mnt), inode, mode | MAY_ACCESS); | |
442 | /* SuS v2 requires we report a read only fs too */ | |
443 | if (res || !(mode & S_IWOTH) || special_file(inode->i_mode)) | |
444 | goto out_path_release; | |
445 | /* | |
446 | * This is a rare case where using __mnt_is_readonly() | |
447 | * is OK without a mnt_want/drop_write() pair. Since | |
448 | * no actual write to the fs is performed here, we do | |
449 | * not need to telegraph to that to anyone. | |
450 | * | |
451 | * By doing this, we accept that this access is | |
452 | * inherently racy and know that the fs may change | |
453 | * state before we even see this result. | |
454 | */ | |
455 | if (__mnt_is_readonly(path.mnt)) | |
456 | res = -EROFS; | |
457 | ||
458 | out_path_release: | |
459 | path_put(&path); | |
460 | if (retry_estale(res, lookup_flags)) { | |
461 | lookup_flags |= LOOKUP_REVAL; | |
462 | goto retry; | |
463 | } | |
464 | out: | |
465 | if (old_cred) | |
466 | revert_creds(old_cred); | |
467 | ||
468 | return res; | |
469 | } | |
470 | ||
471 | SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode) | |
472 | { | |
473 | return do_faccessat(dfd, filename, mode, 0); | |
474 | } | |
475 | ||
476 | SYSCALL_DEFINE4(faccessat2, int, dfd, const char __user *, filename, int, mode, | |
477 | int, flags) | |
478 | { | |
479 | return do_faccessat(dfd, filename, mode, flags); | |
480 | } | |
481 | ||
482 | SYSCALL_DEFINE2(access, const char __user *, filename, int, mode) | |
483 | { | |
484 | return do_faccessat(AT_FDCWD, filename, mode, 0); | |
485 | } | |
486 | ||
487 | SYSCALL_DEFINE1(chdir, const char __user *, filename) | |
488 | { | |
489 | struct path path; | |
490 | int error; | |
491 | unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY; | |
492 | retry: | |
493 | error = user_path_at(AT_FDCWD, filename, lookup_flags, &path); | |
494 | if (error) | |
495 | goto out; | |
496 | ||
497 | error = path_permission(&path, MAY_EXEC | MAY_CHDIR); | |
498 | if (error) | |
499 | goto dput_and_out; | |
500 | ||
501 | set_fs_pwd(current->fs, &path); | |
502 | ||
503 | dput_and_out: | |
504 | path_put(&path); | |
505 | if (retry_estale(error, lookup_flags)) { | |
506 | lookup_flags |= LOOKUP_REVAL; | |
507 | goto retry; | |
508 | } | |
509 | out: | |
510 | return error; | |
511 | } | |
512 | ||
513 | SYSCALL_DEFINE1(fchdir, unsigned int, fd) | |
514 | { | |
515 | struct fd f = fdget_raw(fd); | |
516 | int error; | |
517 | ||
518 | error = -EBADF; | |
519 | if (!f.file) | |
520 | goto out; | |
521 | ||
522 | error = -ENOTDIR; | |
523 | if (!d_can_lookup(f.file->f_path.dentry)) | |
524 | goto out_putf; | |
525 | ||
526 | error = file_permission(f.file, MAY_EXEC | MAY_CHDIR); | |
527 | if (!error) | |
528 | set_fs_pwd(current->fs, &f.file->f_path); | |
529 | out_putf: | |
530 | fdput(f); | |
531 | out: | |
532 | return error; | |
533 | } | |
534 | ||
535 | SYSCALL_DEFINE1(chroot, const char __user *, filename) | |
536 | { | |
537 | struct path path; | |
538 | int error; | |
539 | unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY; | |
540 | retry: | |
541 | error = user_path_at(AT_FDCWD, filename, lookup_flags, &path); | |
542 | if (error) | |
543 | goto out; | |
544 | ||
545 | error = path_permission(&path, MAY_EXEC | MAY_CHDIR); | |
546 | if (error) | |
547 | goto dput_and_out; | |
548 | ||
549 | error = -EPERM; | |
550 | if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT)) | |
551 | goto dput_and_out; | |
552 | error = security_path_chroot(&path); | |
553 | if (error) | |
554 | goto dput_and_out; | |
555 | ||
556 | set_fs_root(current->fs, &path); | |
557 | error = 0; | |
558 | dput_and_out: | |
559 | path_put(&path); | |
560 | if (retry_estale(error, lookup_flags)) { | |
561 | lookup_flags |= LOOKUP_REVAL; | |
562 | goto retry; | |
563 | } | |
564 | out: | |
565 | return error; | |
566 | } | |
567 | ||
568 | int chmod_common(const struct path *path, umode_t mode) | |
569 | { | |
570 | struct inode *inode = path->dentry->d_inode; | |
571 | struct inode *delegated_inode = NULL; | |
572 | struct iattr newattrs; | |
573 | int error; | |
574 | ||
575 | error = mnt_want_write(path->mnt); | |
576 | if (error) | |
577 | return error; | |
578 | retry_deleg: | |
579 | inode_lock(inode); | |
580 | error = security_path_chmod(path, mode); | |
581 | if (error) | |
582 | goto out_unlock; | |
583 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); | |
584 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
585 | error = notify_change(mnt_user_ns(path->mnt), path->dentry, | |
586 | &newattrs, &delegated_inode); | |
587 | out_unlock: | |
588 | inode_unlock(inode); | |
589 | if (delegated_inode) { | |
590 | error = break_deleg_wait(&delegated_inode); | |
591 | if (!error) | |
592 | goto retry_deleg; | |
593 | } | |
594 | mnt_drop_write(path->mnt); | |
595 | return error; | |
596 | } | |
597 | ||
598 | int vfs_fchmod(struct file *file, umode_t mode) | |
599 | { | |
600 | audit_file(file); | |
601 | return chmod_common(&file->f_path, mode); | |
602 | } | |
603 | ||
604 | SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode) | |
605 | { | |
606 | struct fd f = fdget(fd); | |
607 | int err = -EBADF; | |
608 | ||
609 | if (f.file) { | |
610 | err = vfs_fchmod(f.file, mode); | |
611 | fdput(f); | |
612 | } | |
613 | return err; | |
614 | } | |
615 | ||
616 | static int do_fchmodat(int dfd, const char __user *filename, umode_t mode) | |
617 | { | |
618 | struct path path; | |
619 | int error; | |
620 | unsigned int lookup_flags = LOOKUP_FOLLOW; | |
621 | retry: | |
622 | error = user_path_at(dfd, filename, lookup_flags, &path); | |
623 | if (!error) { | |
624 | error = chmod_common(&path, mode); | |
625 | path_put(&path); | |
626 | if (retry_estale(error, lookup_flags)) { | |
627 | lookup_flags |= LOOKUP_REVAL; | |
628 | goto retry; | |
629 | } | |
630 | } | |
631 | return error; | |
632 | } | |
633 | ||
634 | SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, | |
635 | umode_t, mode) | |
636 | { | |
637 | return do_fchmodat(dfd, filename, mode); | |
638 | } | |
639 | ||
640 | SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode) | |
641 | { | |
642 | return do_fchmodat(AT_FDCWD, filename, mode); | |
643 | } | |
644 | ||
645 | int chown_common(const struct path *path, uid_t user, gid_t group) | |
646 | { | |
647 | struct user_namespace *mnt_userns; | |
648 | struct inode *inode = path->dentry->d_inode; | |
649 | struct inode *delegated_inode = NULL; | |
650 | int error; | |
651 | struct iattr newattrs; | |
652 | kuid_t uid; | |
653 | kgid_t gid; | |
654 | ||
655 | uid = make_kuid(current_user_ns(), user); | |
656 | gid = make_kgid(current_user_ns(), group); | |
657 | ||
658 | mnt_userns = mnt_user_ns(path->mnt); | |
659 | uid = kuid_from_mnt(mnt_userns, uid); | |
660 | gid = kgid_from_mnt(mnt_userns, gid); | |
661 | ||
662 | retry_deleg: | |
663 | newattrs.ia_valid = ATTR_CTIME; | |
664 | if (user != (uid_t) -1) { | |
665 | if (!uid_valid(uid)) | |
666 | return -EINVAL; | |
667 | newattrs.ia_valid |= ATTR_UID; | |
668 | newattrs.ia_uid = uid; | |
669 | } | |
670 | if (group != (gid_t) -1) { | |
671 | if (!gid_valid(gid)) | |
672 | return -EINVAL; | |
673 | newattrs.ia_valid |= ATTR_GID; | |
674 | newattrs.ia_gid = gid; | |
675 | } | |
676 | if (!S_ISDIR(inode->i_mode)) | |
677 | newattrs.ia_valid |= | |
678 | ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV; | |
679 | inode_lock(inode); | |
680 | error = security_path_chown(path, uid, gid); | |
681 | if (!error) | |
682 | error = notify_change(mnt_userns, path->dentry, &newattrs, | |
683 | &delegated_inode); | |
684 | inode_unlock(inode); | |
685 | if (delegated_inode) { | |
686 | error = break_deleg_wait(&delegated_inode); | |
687 | if (!error) | |
688 | goto retry_deleg; | |
689 | } | |
690 | return error; | |
691 | } | |
692 | ||
693 | int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group, | |
694 | int flag) | |
695 | { | |
696 | struct path path; | |
697 | int error = -EINVAL; | |
698 | int lookup_flags; | |
699 | ||
700 | if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) | |
701 | goto out; | |
702 | ||
703 | lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; | |
704 | if (flag & AT_EMPTY_PATH) | |
705 | lookup_flags |= LOOKUP_EMPTY; | |
706 | retry: | |
707 | error = user_path_at(dfd, filename, lookup_flags, &path); | |
708 | if (error) | |
709 | goto out; | |
710 | error = mnt_want_write(path.mnt); | |
711 | if (error) | |
712 | goto out_release; | |
713 | error = chown_common(&path, user, group); | |
714 | mnt_drop_write(path.mnt); | |
715 | out_release: | |
716 | path_put(&path); | |
717 | if (retry_estale(error, lookup_flags)) { | |
718 | lookup_flags |= LOOKUP_REVAL; | |
719 | goto retry; | |
720 | } | |
721 | out: | |
722 | return error; | |
723 | } | |
724 | ||
725 | SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user, | |
726 | gid_t, group, int, flag) | |
727 | { | |
728 | return do_fchownat(dfd, filename, user, group, flag); | |
729 | } | |
730 | ||
731 | SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group) | |
732 | { | |
733 | return do_fchownat(AT_FDCWD, filename, user, group, 0); | |
734 | } | |
735 | ||
736 | SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group) | |
737 | { | |
738 | return do_fchownat(AT_FDCWD, filename, user, group, | |
739 | AT_SYMLINK_NOFOLLOW); | |
740 | } | |
741 | ||
742 | int vfs_fchown(struct file *file, uid_t user, gid_t group) | |
743 | { | |
744 | int error; | |
745 | ||
746 | error = mnt_want_write_file(file); | |
747 | if (error) | |
748 | return error; | |
749 | audit_file(file); | |
750 | error = chown_common(&file->f_path, user, group); | |
751 | mnt_drop_write_file(file); | |
752 | return error; | |
753 | } | |
754 | ||
755 | int ksys_fchown(unsigned int fd, uid_t user, gid_t group) | |
756 | { | |
757 | struct fd f = fdget(fd); | |
758 | int error = -EBADF; | |
759 | ||
760 | if (f.file) { | |
761 | error = vfs_fchown(f.file, user, group); | |
762 | fdput(f); | |
763 | } | |
764 | return error; | |
765 | } | |
766 | ||
767 | SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group) | |
768 | { | |
769 | return ksys_fchown(fd, user, group); | |
770 | } | |
771 | ||
772 | static int do_dentry_open(struct file *f, | |
773 | struct inode *inode, | |
774 | int (*open)(struct inode *, struct file *)) | |
775 | { | |
776 | static const struct file_operations empty_fops = {}; | |
777 | int error; | |
778 | ||
779 | path_get(&f->f_path); | |
780 | f->f_inode = inode; | |
781 | f->f_mapping = inode->i_mapping; | |
782 | f->f_wb_err = filemap_sample_wb_err(f->f_mapping); | |
783 | f->f_sb_err = file_sample_sb_err(f); | |
784 | ||
785 | if (unlikely(f->f_flags & O_PATH)) { | |
786 | f->f_mode = FMODE_PATH | FMODE_OPENED; | |
787 | f->f_op = &empty_fops; | |
788 | return 0; | |
789 | } | |
790 | ||
791 | if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) { | |
792 | error = get_write_access(inode); | |
793 | if (unlikely(error)) | |
794 | goto cleanup_file; | |
795 | error = __mnt_want_write(f->f_path.mnt); | |
796 | if (unlikely(error)) { | |
797 | put_write_access(inode); | |
798 | goto cleanup_file; | |
799 | } | |
800 | f->f_mode |= FMODE_WRITER; | |
801 | } | |
802 | ||
803 | /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */ | |
804 | if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)) | |
805 | f->f_mode |= FMODE_ATOMIC_POS; | |
806 | ||
807 | f->f_op = fops_get(inode->i_fop); | |
808 | if (WARN_ON(!f->f_op)) { | |
809 | error = -ENODEV; | |
810 | goto cleanup_all; | |
811 | } | |
812 | ||
813 | error = security_file_open(f); | |
814 | if (error) | |
815 | goto cleanup_all; | |
816 | ||
817 | error = break_lease(locks_inode(f), f->f_flags); | |
818 | if (error) | |
819 | goto cleanup_all; | |
820 | ||
821 | /* normally all 3 are set; ->open() can clear them if needed */ | |
822 | f->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; | |
823 | if (!open) | |
824 | open = f->f_op->open; | |
825 | if (open) { | |
826 | error = open(inode, f); | |
827 | if (error) | |
828 | goto cleanup_all; | |
829 | } | |
830 | f->f_mode |= FMODE_OPENED; | |
831 | if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) | |
832 | i_readcount_inc(inode); | |
833 | if ((f->f_mode & FMODE_READ) && | |
834 | likely(f->f_op->read || f->f_op->read_iter)) | |
835 | f->f_mode |= FMODE_CAN_READ; | |
836 | if ((f->f_mode & FMODE_WRITE) && | |
837 | likely(f->f_op->write || f->f_op->write_iter)) | |
838 | f->f_mode |= FMODE_CAN_WRITE; | |
839 | ||
840 | f->f_write_hint = WRITE_LIFE_NOT_SET; | |
841 | f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); | |
842 | ||
843 | file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); | |
844 | ||
845 | /* NB: we're sure to have correct a_ops only after f_op->open */ | |
846 | if (f->f_flags & O_DIRECT) { | |
847 | if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) | |
848 | return -EINVAL; | |
849 | } | |
850 | ||
851 | /* | |
852 | * XXX: Huge page cache doesn't support writing yet. Drop all page | |
853 | * cache for this file before processing writes. | |
854 | */ | |
855 | if ((f->f_mode & FMODE_WRITE) && filemap_nr_thps(inode->i_mapping)) | |
856 | truncate_pagecache(inode, 0); | |
857 | ||
858 | return 0; | |
859 | ||
860 | cleanup_all: | |
861 | if (WARN_ON_ONCE(error > 0)) | |
862 | error = -EINVAL; | |
863 | fops_put(f->f_op); | |
864 | if (f->f_mode & FMODE_WRITER) { | |
865 | put_write_access(inode); | |
866 | __mnt_drop_write(f->f_path.mnt); | |
867 | } | |
868 | cleanup_file: | |
869 | path_put(&f->f_path); | |
870 | f->f_path.mnt = NULL; | |
871 | f->f_path.dentry = NULL; | |
872 | f->f_inode = NULL; | |
873 | return error; | |
874 | } | |
875 | ||
876 | /** | |
877 | * finish_open - finish opening a file | |
878 | * @file: file pointer | |
879 | * @dentry: pointer to dentry | |
880 | * @open: open callback | |
881 | * @opened: state of open | |
882 | * | |
883 | * This can be used to finish opening a file passed to i_op->atomic_open(). | |
884 | * | |
885 | * If the open callback is set to NULL, then the standard f_op->open() | |
886 | * filesystem callback is substituted. | |
887 | * | |
888 | * NB: the dentry reference is _not_ consumed. If, for example, the dentry is | |
889 | * the return value of d_splice_alias(), then the caller needs to perform dput() | |
890 | * on it after finish_open(). | |
891 | * | |
892 | * Returns zero on success or -errno if the open failed. | |
893 | */ | |
894 | int finish_open(struct file *file, struct dentry *dentry, | |
895 | int (*open)(struct inode *, struct file *)) | |
896 | { | |
897 | BUG_ON(file->f_mode & FMODE_OPENED); /* once it's opened, it's opened */ | |
898 | ||
899 | file->f_path.dentry = dentry; | |
900 | return do_dentry_open(file, d_backing_inode(dentry), open); | |
901 | } | |
902 | EXPORT_SYMBOL(finish_open); | |
903 | ||
904 | /** | |
905 | * finish_no_open - finish ->atomic_open() without opening the file | |
906 | * | |
907 | * @file: file pointer | |
908 | * @dentry: dentry or NULL (as returned from ->lookup()) | |
909 | * | |
910 | * This can be used to set the result of a successful lookup in ->atomic_open(). | |
911 | * | |
912 | * NB: unlike finish_open() this function does consume the dentry reference and | |
913 | * the caller need not dput() it. | |
914 | * | |
915 | * Returns "0" which must be the return value of ->atomic_open() after having | |
916 | * called this function. | |
917 | */ | |
918 | int finish_no_open(struct file *file, struct dentry *dentry) | |
919 | { | |
920 | file->f_path.dentry = dentry; | |
921 | return 0; | |
922 | } | |
923 | EXPORT_SYMBOL(finish_no_open); | |
924 | ||
925 | char *file_path(struct file *filp, char *buf, int buflen) | |
926 | { | |
927 | return d_path(&filp->f_path, buf, buflen); | |
928 | } | |
929 | EXPORT_SYMBOL(file_path); | |
930 | ||
931 | /** | |
932 | * vfs_open - open the file at the given path | |
933 | * @path: path to open | |
934 | * @file: newly allocated file with f_flag initialized | |
935 | * @cred: credentials to use | |
936 | */ | |
937 | int vfs_open(const struct path *path, struct file *file) | |
938 | { | |
939 | file->f_path = *path; | |
940 | return do_dentry_open(file, d_backing_inode(path->dentry), NULL); | |
941 | } | |
942 | ||
943 | struct file *dentry_open(const struct path *path, int flags, | |
944 | const struct cred *cred) | |
945 | { | |
946 | int error; | |
947 | struct file *f; | |
948 | ||
949 | validate_creds(cred); | |
950 | ||
951 | /* We must always pass in a valid mount pointer. */ | |
952 | BUG_ON(!path->mnt); | |
953 | ||
954 | f = alloc_empty_file(flags, cred); | |
955 | if (!IS_ERR(f)) { | |
956 | error = vfs_open(path, f); | |
957 | if (error) { | |
958 | fput(f); | |
959 | f = ERR_PTR(error); | |
960 | } | |
961 | } | |
962 | return f; | |
963 | } | |
964 | EXPORT_SYMBOL(dentry_open); | |
965 | ||
966 | struct file *open_with_fake_path(const struct path *path, int flags, | |
967 | struct inode *inode, const struct cred *cred) | |
968 | { | |
969 | struct file *f = alloc_empty_file_noaccount(flags, cred); | |
970 | if (!IS_ERR(f)) { | |
971 | int error; | |
972 | ||
973 | f->f_path = *path; | |
974 | error = do_dentry_open(f, inode, NULL); | |
975 | if (error) { | |
976 | fput(f); | |
977 | f = ERR_PTR(error); | |
978 | } | |
979 | } | |
980 | return f; | |
981 | } | |
982 | EXPORT_SYMBOL(open_with_fake_path); | |
983 | ||
984 | #define WILL_CREATE(flags) (flags & (O_CREAT | __O_TMPFILE)) | |
985 | #define O_PATH_FLAGS (O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC) | |
986 | ||
987 | inline struct open_how build_open_how(int flags, umode_t mode) | |
988 | { | |
989 | struct open_how how = { | |
990 | .flags = flags & VALID_OPEN_FLAGS, | |
991 | .mode = mode & S_IALLUGO, | |
992 | }; | |
993 | ||
994 | /* O_PATH beats everything else. */ | |
995 | if (how.flags & O_PATH) | |
996 | how.flags &= O_PATH_FLAGS; | |
997 | /* Modes should only be set for create-like flags. */ | |
998 | if (!WILL_CREATE(how.flags)) | |
999 | how.mode = 0; | |
1000 | return how; | |
1001 | } | |
1002 | ||
1003 | inline int build_open_flags(const struct open_how *how, struct open_flags *op) | |
1004 | { | |
1005 | int flags = how->flags; | |
1006 | int lookup_flags = 0; | |
1007 | int acc_mode = ACC_MODE(flags); | |
1008 | ||
1009 | /* Must never be set by userspace */ | |
1010 | flags &= ~(FMODE_NONOTIFY | O_CLOEXEC); | |
1011 | ||
1012 | /* | |
1013 | * Older syscalls implicitly clear all of the invalid flags or argument | |
1014 | * values before calling build_open_flags(), but openat2(2) checks all | |
1015 | * of its arguments. | |
1016 | */ | |
1017 | if (flags & ~VALID_OPEN_FLAGS) | |
1018 | return -EINVAL; | |
1019 | if (how->resolve & ~VALID_RESOLVE_FLAGS) | |
1020 | return -EINVAL; | |
1021 | ||
1022 | /* Scoping flags are mutually exclusive. */ | |
1023 | if ((how->resolve & RESOLVE_BENEATH) && (how->resolve & RESOLVE_IN_ROOT)) | |
1024 | return -EINVAL; | |
1025 | ||
1026 | /* Deal with the mode. */ | |
1027 | if (WILL_CREATE(flags)) { | |
1028 | if (how->mode & ~S_IALLUGO) | |
1029 | return -EINVAL; | |
1030 | op->mode = how->mode | S_IFREG; | |
1031 | } else { | |
1032 | if (how->mode != 0) | |
1033 | return -EINVAL; | |
1034 | op->mode = 0; | |
1035 | } | |
1036 | ||
1037 | /* | |
1038 | * In order to ensure programs get explicit errors when trying to use | |
1039 | * O_TMPFILE on old kernels, O_TMPFILE is implemented such that it | |
1040 | * looks like (O_DIRECTORY|O_RDWR & ~O_CREAT) to old kernels. But we | |
1041 | * have to require userspace to explicitly set it. | |
1042 | */ | |
1043 | if (flags & __O_TMPFILE) { | |
1044 | if ((flags & O_TMPFILE_MASK) != O_TMPFILE) | |
1045 | return -EINVAL; | |
1046 | if (!(acc_mode & MAY_WRITE)) | |
1047 | return -EINVAL; | |
1048 | } | |
1049 | if (flags & O_PATH) { | |
1050 | /* O_PATH only permits certain other flags to be set. */ | |
1051 | if (flags & ~O_PATH_FLAGS) | |
1052 | return -EINVAL; | |
1053 | acc_mode = 0; | |
1054 | } | |
1055 | ||
1056 | /* | |
1057 | * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only | |
1058 | * check for O_DSYNC if the need any syncing at all we enforce it's | |
1059 | * always set instead of having to deal with possibly weird behaviour | |
1060 | * for malicious applications setting only __O_SYNC. | |
1061 | */ | |
1062 | if (flags & __O_SYNC) | |
1063 | flags |= O_DSYNC; | |
1064 | ||
1065 | op->open_flag = flags; | |
1066 | ||
1067 | /* O_TRUNC implies we need access checks for write permissions */ | |
1068 | if (flags & O_TRUNC) | |
1069 | acc_mode |= MAY_WRITE; | |
1070 | ||
1071 | /* Allow the LSM permission hook to distinguish append | |
1072 | access from general write access. */ | |
1073 | if (flags & O_APPEND) | |
1074 | acc_mode |= MAY_APPEND; | |
1075 | ||
1076 | op->acc_mode = acc_mode; | |
1077 | ||
1078 | op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN; | |
1079 | ||
1080 | if (flags & O_CREAT) { | |
1081 | op->intent |= LOOKUP_CREATE; | |
1082 | if (flags & O_EXCL) { | |
1083 | op->intent |= LOOKUP_EXCL; | |
1084 | flags |= O_NOFOLLOW; | |
1085 | } | |
1086 | } | |
1087 | ||
1088 | if (flags & O_DIRECTORY) | |
1089 | lookup_flags |= LOOKUP_DIRECTORY; | |
1090 | if (!(flags & O_NOFOLLOW)) | |
1091 | lookup_flags |= LOOKUP_FOLLOW; | |
1092 | ||
1093 | if (how->resolve & RESOLVE_NO_XDEV) | |
1094 | lookup_flags |= LOOKUP_NO_XDEV; | |
1095 | if (how->resolve & RESOLVE_NO_MAGICLINKS) | |
1096 | lookup_flags |= LOOKUP_NO_MAGICLINKS; | |
1097 | if (how->resolve & RESOLVE_NO_SYMLINKS) | |
1098 | lookup_flags |= LOOKUP_NO_SYMLINKS; | |
1099 | if (how->resolve & RESOLVE_BENEATH) | |
1100 | lookup_flags |= LOOKUP_BENEATH; | |
1101 | if (how->resolve & RESOLVE_IN_ROOT) | |
1102 | lookup_flags |= LOOKUP_IN_ROOT; | |
1103 | if (how->resolve & RESOLVE_CACHED) { | |
1104 | /* Don't bother even trying for create/truncate/tmpfile open */ | |
1105 | if (flags & (O_TRUNC | O_CREAT | O_TMPFILE)) | |
1106 | return -EAGAIN; | |
1107 | lookup_flags |= LOOKUP_CACHED; | |
1108 | } | |
1109 | ||
1110 | op->lookup_flags = lookup_flags; | |
1111 | return 0; | |
1112 | } | |
1113 | ||
1114 | /** | |
1115 | * file_open_name - open file and return file pointer | |
1116 | * | |
1117 | * @name: struct filename containing path to open | |
1118 | * @flags: open flags as per the open(2) second argument | |
1119 | * @mode: mode for the new file if O_CREAT is set, else ignored | |
1120 | * | |
1121 | * This is the helper to open a file from kernelspace if you really | |
1122 | * have to. But in generally you should not do this, so please move | |
1123 | * along, nothing to see here.. | |
1124 | */ | |
1125 | struct file *file_open_name(struct filename *name, int flags, umode_t mode) | |
1126 | { | |
1127 | struct open_flags op; | |
1128 | struct open_how how = build_open_how(flags, mode); | |
1129 | int err = build_open_flags(&how, &op); | |
1130 | if (err) | |
1131 | return ERR_PTR(err); | |
1132 | return do_filp_open(AT_FDCWD, name, &op); | |
1133 | } | |
1134 | ||
1135 | /** | |
1136 | * filp_open - open file and return file pointer | |
1137 | * | |
1138 | * @filename: path to open | |
1139 | * @flags: open flags as per the open(2) second argument | |
1140 | * @mode: mode for the new file if O_CREAT is set, else ignored | |
1141 | * | |
1142 | * This is the helper to open a file from kernelspace if you really | |
1143 | * have to. But in generally you should not do this, so please move | |
1144 | * along, nothing to see here.. | |
1145 | */ | |
1146 | struct file *filp_open(const char *filename, int flags, umode_t mode) | |
1147 | { | |
1148 | struct filename *name = getname_kernel(filename); | |
1149 | struct file *file = ERR_CAST(name); | |
1150 | ||
1151 | if (!IS_ERR(name)) { | |
1152 | file = file_open_name(name, flags, mode); | |
1153 | putname(name); | |
1154 | } | |
1155 | return file; | |
1156 | } | |
1157 | EXPORT_SYMBOL(filp_open); | |
1158 | ||
1159 | struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt, | |
1160 | const char *filename, int flags, umode_t mode) | |
1161 | { | |
1162 | struct open_flags op; | |
1163 | struct open_how how = build_open_how(flags, mode); | |
1164 | int err = build_open_flags(&how, &op); | |
1165 | if (err) | |
1166 | return ERR_PTR(err); | |
1167 | return do_file_open_root(dentry, mnt, filename, &op); | |
1168 | } | |
1169 | EXPORT_SYMBOL(file_open_root); | |
1170 | ||
1171 | static long do_sys_openat2(int dfd, const char __user *filename, | |
1172 | struct open_how *how) | |
1173 | { | |
1174 | struct open_flags op; | |
1175 | int fd = build_open_flags(how, &op); | |
1176 | struct filename *tmp; | |
1177 | ||
1178 | if (fd) | |
1179 | return fd; | |
1180 | ||
1181 | tmp = getname(filename); | |
1182 | if (IS_ERR(tmp)) | |
1183 | return PTR_ERR(tmp); | |
1184 | ||
1185 | fd = get_unused_fd_flags(how->flags); | |
1186 | if (fd >= 0) { | |
1187 | struct file *f = do_filp_open(dfd, tmp, &op); | |
1188 | if (IS_ERR(f)) { | |
1189 | put_unused_fd(fd); | |
1190 | fd = PTR_ERR(f); | |
1191 | } else { | |
1192 | fsnotify_open(f); | |
1193 | fd_install(fd, f); | |
1194 | } | |
1195 | } | |
1196 | putname(tmp); | |
1197 | return fd; | |
1198 | } | |
1199 | ||
1200 | long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode) | |
1201 | { | |
1202 | struct open_how how = build_open_how(flags, mode); | |
1203 | return do_sys_openat2(dfd, filename, &how); | |
1204 | } | |
1205 | ||
1206 | ||
1207 | SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode) | |
1208 | { | |
1209 | if (force_o_largefile()) | |
1210 | flags |= O_LARGEFILE; | |
1211 | return do_sys_open(AT_FDCWD, filename, flags, mode); | |
1212 | } | |
1213 | ||
1214 | SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, | |
1215 | umode_t, mode) | |
1216 | { | |
1217 | if (force_o_largefile()) | |
1218 | flags |= O_LARGEFILE; | |
1219 | return do_sys_open(dfd, filename, flags, mode); | |
1220 | } | |
1221 | ||
1222 | SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename, | |
1223 | struct open_how __user *, how, size_t, usize) | |
1224 | { | |
1225 | int err; | |
1226 | struct open_how tmp; | |
1227 | ||
1228 | BUILD_BUG_ON(sizeof(struct open_how) < OPEN_HOW_SIZE_VER0); | |
1229 | BUILD_BUG_ON(sizeof(struct open_how) != OPEN_HOW_SIZE_LATEST); | |
1230 | ||
1231 | if (unlikely(usize < OPEN_HOW_SIZE_VER0)) | |
1232 | return -EINVAL; | |
1233 | ||
1234 | err = copy_struct_from_user(&tmp, sizeof(tmp), how, usize); | |
1235 | if (err) | |
1236 | return err; | |
1237 | ||
1238 | /* O_LARGEFILE is only allowed for non-O_PATH. */ | |
1239 | if (!(tmp.flags & O_PATH) && force_o_largefile()) | |
1240 | tmp.flags |= O_LARGEFILE; | |
1241 | ||
1242 | return do_sys_openat2(dfd, filename, &tmp); | |
1243 | } | |
1244 | ||
1245 | #ifdef CONFIG_COMPAT | |
1246 | /* | |
1247 | * Exactly like sys_open(), except that it doesn't set the | |
1248 | * O_LARGEFILE flag. | |
1249 | */ | |
1250 | COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode) | |
1251 | { | |
1252 | return do_sys_open(AT_FDCWD, filename, flags, mode); | |
1253 | } | |
1254 | ||
1255 | /* | |
1256 | * Exactly like sys_openat(), except that it doesn't set the | |
1257 | * O_LARGEFILE flag. | |
1258 | */ | |
1259 | COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode) | |
1260 | { | |
1261 | return do_sys_open(dfd, filename, flags, mode); | |
1262 | } | |
1263 | #endif | |
1264 | ||
1265 | #ifndef __alpha__ | |
1266 | ||
1267 | /* | |
1268 | * For backward compatibility? Maybe this should be moved | |
1269 | * into arch/i386 instead? | |
1270 | */ | |
1271 | SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode) | |
1272 | { | |
1273 | int flags = O_CREAT | O_WRONLY | O_TRUNC; | |
1274 | ||
1275 | if (force_o_largefile()) | |
1276 | flags |= O_LARGEFILE; | |
1277 | return do_sys_open(AT_FDCWD, pathname, flags, mode); | |
1278 | } | |
1279 | #endif | |
1280 | ||
1281 | /* | |
1282 | * "id" is the POSIX thread ID. We use the | |
1283 | * files pointer for this.. | |
1284 | */ | |
1285 | int filp_close(struct file *filp, fl_owner_t id) | |
1286 | { | |
1287 | int retval = 0; | |
1288 | ||
1289 | if (!file_count(filp)) { | |
1290 | printk(KERN_ERR "VFS: Close: file count is 0\n"); | |
1291 | return 0; | |
1292 | } | |
1293 | ||
1294 | if (filp->f_op->flush) | |
1295 | retval = filp->f_op->flush(filp, id); | |
1296 | ||
1297 | if (likely(!(filp->f_mode & FMODE_PATH))) { | |
1298 | dnotify_flush(filp, id); | |
1299 | locks_remove_posix(filp, id); | |
1300 | } | |
1301 | fput(filp); | |
1302 | return retval; | |
1303 | } | |
1304 | ||
1305 | EXPORT_SYMBOL(filp_close); | |
1306 | ||
1307 | /* | |
1308 | * Careful here! We test whether the file pointer is NULL before | |
1309 | * releasing the fd. This ensures that one clone task can't release | |
1310 | * an fd while another clone is opening it. | |
1311 | */ | |
1312 | SYSCALL_DEFINE1(close, unsigned int, fd) | |
1313 | { | |
1314 | int retval = close_fd(fd); | |
1315 | ||
1316 | /* can't restart close syscall because file table entry was cleared */ | |
1317 | if (unlikely(retval == -ERESTARTSYS || | |
1318 | retval == -ERESTARTNOINTR || | |
1319 | retval == -ERESTARTNOHAND || | |
1320 | retval == -ERESTART_RESTARTBLOCK)) | |
1321 | retval = -EINTR; | |
1322 | ||
1323 | return retval; | |
1324 | } | |
1325 | ||
1326 | /** | |
1327 | * close_range() - Close all file descriptors in a given range. | |
1328 | * | |
1329 | * @fd: starting file descriptor to close | |
1330 | * @max_fd: last file descriptor to close | |
1331 | * @flags: reserved for future extensions | |
1332 | * | |
1333 | * This closes a range of file descriptors. All file descriptors | |
1334 | * from @fd up to and including @max_fd are closed. | |
1335 | * Currently, errors to close a given file descriptor are ignored. | |
1336 | */ | |
1337 | SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd, | |
1338 | unsigned int, flags) | |
1339 | { | |
1340 | return __close_range(fd, max_fd, flags); | |
1341 | } | |
1342 | ||
1343 | /* | |
1344 | * This routine simulates a hangup on the tty, to arrange that users | |
1345 | * are given clean terminals at login time. | |
1346 | */ | |
1347 | SYSCALL_DEFINE0(vhangup) | |
1348 | { | |
1349 | if (capable(CAP_SYS_TTY_CONFIG)) { | |
1350 | tty_vhangup_self(); | |
1351 | return 0; | |
1352 | } | |
1353 | return -EPERM; | |
1354 | } | |
1355 | ||
1356 | /* | |
1357 | * Called when an inode is about to be open. | |
1358 | * We use this to disallow opening large files on 32bit systems if | |
1359 | * the caller didn't specify O_LARGEFILE. On 64bit systems we force | |
1360 | * on this flag in sys_open. | |
1361 | */ | |
1362 | int generic_file_open(struct inode * inode, struct file * filp) | |
1363 | { | |
1364 | if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) | |
1365 | return -EOVERFLOW; | |
1366 | return 0; | |
1367 | } | |
1368 | ||
1369 | EXPORT_SYMBOL(generic_file_open); | |
1370 | ||
1371 | /* | |
1372 | * This is used by subsystems that don't want seekable | |
1373 | * file descriptors. The function is not supposed to ever fail, the only | |
1374 | * reason it returns an 'int' and not 'void' is so that it can be plugged | |
1375 | * directly into file_operations structure. | |
1376 | */ | |
1377 | int nonseekable_open(struct inode *inode, struct file *filp) | |
1378 | { | |
1379 | filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); | |
1380 | return 0; | |
1381 | } | |
1382 | ||
1383 | EXPORT_SYMBOL(nonseekable_open); | |
1384 | ||
1385 | /* | |
1386 | * stream_open is used by subsystems that want stream-like file descriptors. | |
1387 | * Such file descriptors are not seekable and don't have notion of position | |
1388 | * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL). | |
1389 | * Contrary to file descriptors of other regular files, .read() and .write() | |
1390 | * can run simultaneously. | |
1391 | * | |
1392 | * stream_open never fails and is marked to return int so that it could be | |
1393 | * directly used as file_operations.open . | |
1394 | */ | |
1395 | int stream_open(struct inode *inode, struct file *filp) | |
1396 | { | |
1397 | filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS); | |
1398 | filp->f_mode |= FMODE_STREAM; | |
1399 | return 0; | |
1400 | } | |
1401 | ||
1402 | EXPORT_SYMBOL(stream_open); |