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1 | /* | |
2 | * linux/fs/open.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/string.h> | |
8 | #include <linux/mm.h> | |
9 | #include <linux/file.h> | |
10 | #include <linux/fdtable.h> | |
11 | #include <linux/quotaops.h> | |
12 | #include <linux/fsnotify.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/tty.h> | |
16 | #include <linux/namei.h> | |
17 | #include <linux/backing-dev.h> | |
18 | #include <linux/capability.h> | |
19 | #include <linux/securebits.h> | |
20 | #include <linux/security.h> | |
21 | #include <linux/mount.h> | |
22 | #include <linux/vfs.h> | |
23 | #include <linux/fcntl.h> | |
24 | #include <asm/uaccess.h> | |
25 | #include <linux/fs.h> | |
26 | #include <linux/personality.h> | |
27 | #include <linux/pagemap.h> | |
28 | #include <linux/syscalls.h> | |
29 | #include <linux/rcupdate.h> | |
30 | #include <linux/audit.h> | |
31 | #include <linux/falloc.h> | |
32 | #include <linux/fs_struct.h> | |
33 | ||
34 | #include "internal.h" | |
35 | ||
36 | int vfs_statfs(struct dentry *dentry, struct kstatfs *buf) | |
37 | { | |
38 | int retval = -ENODEV; | |
39 | ||
40 | if (dentry) { | |
41 | retval = -ENOSYS; | |
42 | if (dentry->d_sb->s_op->statfs) { | |
43 | memset(buf, 0, sizeof(*buf)); | |
44 | retval = security_sb_statfs(dentry); | |
45 | if (retval) | |
46 | return retval; | |
47 | retval = dentry->d_sb->s_op->statfs(dentry, buf); | |
48 | if (retval == 0 && buf->f_frsize == 0) | |
49 | buf->f_frsize = buf->f_bsize; | |
50 | } | |
51 | } | |
52 | return retval; | |
53 | } | |
54 | ||
55 | EXPORT_SYMBOL(vfs_statfs); | |
56 | ||
57 | static int vfs_statfs_native(struct dentry *dentry, struct statfs *buf) | |
58 | { | |
59 | struct kstatfs st; | |
60 | int retval; | |
61 | ||
62 | retval = vfs_statfs(dentry, &st); | |
63 | if (retval) | |
64 | return retval; | |
65 | ||
66 | if (sizeof(*buf) == sizeof(st)) | |
67 | memcpy(buf, &st, sizeof(st)); | |
68 | else { | |
69 | if (sizeof buf->f_blocks == 4) { | |
70 | if ((st.f_blocks | st.f_bfree | st.f_bavail | | |
71 | st.f_bsize | st.f_frsize) & | |
72 | 0xffffffff00000000ULL) | |
73 | return -EOVERFLOW; | |
74 | /* | |
75 | * f_files and f_ffree may be -1; it's okay to stuff | |
76 | * that into 32 bits | |
77 | */ | |
78 | if (st.f_files != -1 && | |
79 | (st.f_files & 0xffffffff00000000ULL)) | |
80 | return -EOVERFLOW; | |
81 | if (st.f_ffree != -1 && | |
82 | (st.f_ffree & 0xffffffff00000000ULL)) | |
83 | return -EOVERFLOW; | |
84 | } | |
85 | ||
86 | buf->f_type = st.f_type; | |
87 | buf->f_bsize = st.f_bsize; | |
88 | buf->f_blocks = st.f_blocks; | |
89 | buf->f_bfree = st.f_bfree; | |
90 | buf->f_bavail = st.f_bavail; | |
91 | buf->f_files = st.f_files; | |
92 | buf->f_ffree = st.f_ffree; | |
93 | buf->f_fsid = st.f_fsid; | |
94 | buf->f_namelen = st.f_namelen; | |
95 | buf->f_frsize = st.f_frsize; | |
96 | memset(buf->f_spare, 0, sizeof(buf->f_spare)); | |
97 | } | |
98 | return 0; | |
99 | } | |
100 | ||
101 | static int vfs_statfs64(struct dentry *dentry, struct statfs64 *buf) | |
102 | { | |
103 | struct kstatfs st; | |
104 | int retval; | |
105 | ||
106 | retval = vfs_statfs(dentry, &st); | |
107 | if (retval) | |
108 | return retval; | |
109 | ||
110 | if (sizeof(*buf) == sizeof(st)) | |
111 | memcpy(buf, &st, sizeof(st)); | |
112 | else { | |
113 | buf->f_type = st.f_type; | |
114 | buf->f_bsize = st.f_bsize; | |
115 | buf->f_blocks = st.f_blocks; | |
116 | buf->f_bfree = st.f_bfree; | |
117 | buf->f_bavail = st.f_bavail; | |
118 | buf->f_files = st.f_files; | |
119 | buf->f_ffree = st.f_ffree; | |
120 | buf->f_fsid = st.f_fsid; | |
121 | buf->f_namelen = st.f_namelen; | |
122 | buf->f_frsize = st.f_frsize; | |
123 | memset(buf->f_spare, 0, sizeof(buf->f_spare)); | |
124 | } | |
125 | return 0; | |
126 | } | |
127 | ||
128 | SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf) | |
129 | { | |
130 | struct path path; | |
131 | int error; | |
132 | ||
133 | error = user_path(pathname, &path); | |
134 | if (!error) { | |
135 | struct statfs tmp; | |
136 | error = vfs_statfs_native(path.dentry, &tmp); | |
137 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
138 | error = -EFAULT; | |
139 | path_put(&path); | |
140 | } | |
141 | return error; | |
142 | } | |
143 | ||
144 | SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf) | |
145 | { | |
146 | struct path path; | |
147 | long error; | |
148 | ||
149 | if (sz != sizeof(*buf)) | |
150 | return -EINVAL; | |
151 | error = user_path(pathname, &path); | |
152 | if (!error) { | |
153 | struct statfs64 tmp; | |
154 | error = vfs_statfs64(path.dentry, &tmp); | |
155 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
156 | error = -EFAULT; | |
157 | path_put(&path); | |
158 | } | |
159 | return error; | |
160 | } | |
161 | ||
162 | SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf) | |
163 | { | |
164 | struct file * file; | |
165 | struct statfs tmp; | |
166 | int error; | |
167 | ||
168 | error = -EBADF; | |
169 | file = fget(fd); | |
170 | if (!file) | |
171 | goto out; | |
172 | error = vfs_statfs_native(file->f_path.dentry, &tmp); | |
173 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
174 | error = -EFAULT; | |
175 | fput(file); | |
176 | out: | |
177 | return error; | |
178 | } | |
179 | ||
180 | SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf) | |
181 | { | |
182 | struct file * file; | |
183 | struct statfs64 tmp; | |
184 | int error; | |
185 | ||
186 | if (sz != sizeof(*buf)) | |
187 | return -EINVAL; | |
188 | ||
189 | error = -EBADF; | |
190 | file = fget(fd); | |
191 | if (!file) | |
192 | goto out; | |
193 | error = vfs_statfs64(file->f_path.dentry, &tmp); | |
194 | if (!error && copy_to_user(buf, &tmp, sizeof(tmp))) | |
195 | error = -EFAULT; | |
196 | fput(file); | |
197 | out: | |
198 | return error; | |
199 | } | |
200 | ||
201 | int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs, | |
202 | struct file *filp) | |
203 | { | |
204 | int ret; | |
205 | struct iattr newattrs; | |
206 | ||
207 | /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ | |
208 | if (length < 0) | |
209 | return -EINVAL; | |
210 | ||
211 | newattrs.ia_size = length; | |
212 | newattrs.ia_valid = ATTR_SIZE | time_attrs; | |
213 | if (filp) { | |
214 | newattrs.ia_file = filp; | |
215 | newattrs.ia_valid |= ATTR_FILE; | |
216 | } | |
217 | ||
218 | /* Remove suid/sgid on truncate too */ | |
219 | ret = should_remove_suid(dentry); | |
220 | if (ret) | |
221 | newattrs.ia_valid |= ret | ATTR_FORCE; | |
222 | ||
223 | mutex_lock(&dentry->d_inode->i_mutex); | |
224 | ret = notify_change(dentry, &newattrs); | |
225 | mutex_unlock(&dentry->d_inode->i_mutex); | |
226 | return ret; | |
227 | } | |
228 | ||
229 | static long do_sys_truncate(const char __user *pathname, loff_t length) | |
230 | { | |
231 | struct path path; | |
232 | struct inode *inode; | |
233 | int error; | |
234 | ||
235 | error = -EINVAL; | |
236 | if (length < 0) /* sorry, but loff_t says... */ | |
237 | goto out; | |
238 | ||
239 | error = user_path(pathname, &path); | |
240 | if (error) | |
241 | goto out; | |
242 | inode = path.dentry->d_inode; | |
243 | ||
244 | /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ | |
245 | error = -EISDIR; | |
246 | if (S_ISDIR(inode->i_mode)) | |
247 | goto dput_and_out; | |
248 | ||
249 | error = -EINVAL; | |
250 | if (!S_ISREG(inode->i_mode)) | |
251 | goto dput_and_out; | |
252 | ||
253 | error = mnt_want_write(path.mnt); | |
254 | if (error) | |
255 | goto dput_and_out; | |
256 | ||
257 | error = inode_permission(inode, MAY_WRITE); | |
258 | if (error) | |
259 | goto mnt_drop_write_and_out; | |
260 | ||
261 | error = -EPERM; | |
262 | if (IS_APPEND(inode)) | |
263 | goto mnt_drop_write_and_out; | |
264 | ||
265 | error = get_write_access(inode); | |
266 | if (error) | |
267 | goto mnt_drop_write_and_out; | |
268 | ||
269 | /* | |
270 | * Make sure that there are no leases. get_write_access() protects | |
271 | * against the truncate racing with a lease-granting setlease(). | |
272 | */ | |
273 | error = break_lease(inode, FMODE_WRITE); | |
274 | if (error) | |
275 | goto put_write_and_out; | |
276 | ||
277 | error = locks_verify_truncate(inode, NULL, length); | |
278 | if (!error) | |
279 | error = security_path_truncate(&path, length, 0); | |
280 | if (!error) { | |
281 | vfs_dq_init(inode); | |
282 | error = do_truncate(path.dentry, length, 0, NULL); | |
283 | } | |
284 | ||
285 | put_write_and_out: | |
286 | put_write_access(inode); | |
287 | mnt_drop_write_and_out: | |
288 | mnt_drop_write(path.mnt); | |
289 | dput_and_out: | |
290 | path_put(&path); | |
291 | out: | |
292 | return error; | |
293 | } | |
294 | ||
295 | SYSCALL_DEFINE2(truncate, const char __user *, path, long, length) | |
296 | { | |
297 | return do_sys_truncate(path, length); | |
298 | } | |
299 | ||
300 | static long do_sys_ftruncate(unsigned int fd, loff_t length, int small) | |
301 | { | |
302 | struct inode * inode; | |
303 | struct dentry *dentry; | |
304 | struct file * file; | |
305 | int error; | |
306 | ||
307 | error = -EINVAL; | |
308 | if (length < 0) | |
309 | goto out; | |
310 | error = -EBADF; | |
311 | file = fget(fd); | |
312 | if (!file) | |
313 | goto out; | |
314 | ||
315 | /* explicitly opened as large or we are on 64-bit box */ | |
316 | if (file->f_flags & O_LARGEFILE) | |
317 | small = 0; | |
318 | ||
319 | dentry = file->f_path.dentry; | |
320 | inode = dentry->d_inode; | |
321 | error = -EINVAL; | |
322 | if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) | |
323 | goto out_putf; | |
324 | ||
325 | error = -EINVAL; | |
326 | /* Cannot ftruncate over 2^31 bytes without large file support */ | |
327 | if (small && length > MAX_NON_LFS) | |
328 | goto out_putf; | |
329 | ||
330 | error = -EPERM; | |
331 | if (IS_APPEND(inode)) | |
332 | goto out_putf; | |
333 | ||
334 | error = locks_verify_truncate(inode, file, length); | |
335 | if (!error) | |
336 | error = security_path_truncate(&file->f_path, length, | |
337 | ATTR_MTIME|ATTR_CTIME); | |
338 | if (!error) | |
339 | error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file); | |
340 | out_putf: | |
341 | fput(file); | |
342 | out: | |
343 | return error; | |
344 | } | |
345 | ||
346 | SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length) | |
347 | { | |
348 | long ret = do_sys_ftruncate(fd, length, 1); | |
349 | /* avoid REGPARM breakage on x86: */ | |
350 | asmlinkage_protect(2, ret, fd, length); | |
351 | return ret; | |
352 | } | |
353 | ||
354 | /* LFS versions of truncate are only needed on 32 bit machines */ | |
355 | #if BITS_PER_LONG == 32 | |
356 | SYSCALL_DEFINE(truncate64)(const char __user * path, loff_t length) | |
357 | { | |
358 | return do_sys_truncate(path, length); | |
359 | } | |
360 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS | |
361 | asmlinkage long SyS_truncate64(long path, loff_t length) | |
362 | { | |
363 | return SYSC_truncate64((const char __user *) path, length); | |
364 | } | |
365 | SYSCALL_ALIAS(sys_truncate64, SyS_truncate64); | |
366 | #endif | |
367 | ||
368 | SYSCALL_DEFINE(ftruncate64)(unsigned int fd, loff_t length) | |
369 | { | |
370 | long ret = do_sys_ftruncate(fd, length, 0); | |
371 | /* avoid REGPARM breakage on x86: */ | |
372 | asmlinkage_protect(2, ret, fd, length); | |
373 | return ret; | |
374 | } | |
375 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS | |
376 | asmlinkage long SyS_ftruncate64(long fd, loff_t length) | |
377 | { | |
378 | return SYSC_ftruncate64((unsigned int) fd, length); | |
379 | } | |
380 | SYSCALL_ALIAS(sys_ftruncate64, SyS_ftruncate64); | |
381 | #endif | |
382 | #endif /* BITS_PER_LONG == 32 */ | |
383 | ||
384 | ||
385 | int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len) | |
386 | { | |
387 | struct inode *inode = file->f_path.dentry->d_inode; | |
388 | long ret; | |
389 | ||
390 | if (offset < 0 || len <= 0) | |
391 | return -EINVAL; | |
392 | ||
393 | /* Return error if mode is not supported */ | |
394 | if (mode && !(mode & FALLOC_FL_KEEP_SIZE)) | |
395 | return -EOPNOTSUPP; | |
396 | ||
397 | if (!(file->f_mode & FMODE_WRITE)) | |
398 | return -EBADF; | |
399 | /* | |
400 | * Revalidate the write permissions, in case security policy has | |
401 | * changed since the files were opened. | |
402 | */ | |
403 | ret = security_file_permission(file, MAY_WRITE); | |
404 | if (ret) | |
405 | return ret; | |
406 | ||
407 | if (S_ISFIFO(inode->i_mode)) | |
408 | return -ESPIPE; | |
409 | ||
410 | /* | |
411 | * Let individual file system decide if it supports preallocation | |
412 | * for directories or not. | |
413 | */ | |
414 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) | |
415 | return -ENODEV; | |
416 | ||
417 | /* Check for wrap through zero too */ | |
418 | if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0)) | |
419 | return -EFBIG; | |
420 | ||
421 | if (!inode->i_op->fallocate) | |
422 | return -EOPNOTSUPP; | |
423 | ||
424 | return inode->i_op->fallocate(inode, mode, offset, len); | |
425 | } | |
426 | ||
427 | SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len) | |
428 | { | |
429 | struct file *file; | |
430 | int error = -EBADF; | |
431 | ||
432 | file = fget(fd); | |
433 | if (file) { | |
434 | error = do_fallocate(file, mode, offset, len); | |
435 | fput(file); | |
436 | } | |
437 | ||
438 | return error; | |
439 | } | |
440 | ||
441 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS | |
442 | asmlinkage long SyS_fallocate(long fd, long mode, loff_t offset, loff_t len) | |
443 | { | |
444 | return SYSC_fallocate((int)fd, (int)mode, offset, len); | |
445 | } | |
446 | SYSCALL_ALIAS(sys_fallocate, SyS_fallocate); | |
447 | #endif | |
448 | ||
449 | /* | |
450 | * access() needs to use the real uid/gid, not the effective uid/gid. | |
451 | * We do this by temporarily clearing all FS-related capabilities and | |
452 | * switching the fsuid/fsgid around to the real ones. | |
453 | */ | |
454 | SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode) | |
455 | { | |
456 | const struct cred *old_cred; | |
457 | struct cred *override_cred; | |
458 | struct path path; | |
459 | struct inode *inode; | |
460 | int res; | |
461 | ||
462 | if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ | |
463 | return -EINVAL; | |
464 | ||
465 | override_cred = prepare_creds(); | |
466 | if (!override_cred) | |
467 | return -ENOMEM; | |
468 | ||
469 | override_cred->fsuid = override_cred->uid; | |
470 | override_cred->fsgid = override_cred->gid; | |
471 | ||
472 | if (!issecure(SECURE_NO_SETUID_FIXUP)) { | |
473 | /* Clear the capabilities if we switch to a non-root user */ | |
474 | if (override_cred->uid) | |
475 | cap_clear(override_cred->cap_effective); | |
476 | else | |
477 | override_cred->cap_effective = | |
478 | override_cred->cap_permitted; | |
479 | } | |
480 | ||
481 | old_cred = override_creds(override_cred); | |
482 | ||
483 | res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path); | |
484 | if (res) | |
485 | goto out; | |
486 | ||
487 | inode = path.dentry->d_inode; | |
488 | ||
489 | if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) { | |
490 | /* | |
491 | * MAY_EXEC on regular files is denied if the fs is mounted | |
492 | * with the "noexec" flag. | |
493 | */ | |
494 | res = -EACCES; | |
495 | if (path.mnt->mnt_flags & MNT_NOEXEC) | |
496 | goto out_path_release; | |
497 | } | |
498 | ||
499 | res = inode_permission(inode, mode | MAY_ACCESS); | |
500 | /* SuS v2 requires we report a read only fs too */ | |
501 | if (res || !(mode & S_IWOTH) || special_file(inode->i_mode)) | |
502 | goto out_path_release; | |
503 | /* | |
504 | * This is a rare case where using __mnt_is_readonly() | |
505 | * is OK without a mnt_want/drop_write() pair. Since | |
506 | * no actual write to the fs is performed here, we do | |
507 | * not need to telegraph to that to anyone. | |
508 | * | |
509 | * By doing this, we accept that this access is | |
510 | * inherently racy and know that the fs may change | |
511 | * state before we even see this result. | |
512 | */ | |
513 | if (__mnt_is_readonly(path.mnt)) | |
514 | res = -EROFS; | |
515 | ||
516 | out_path_release: | |
517 | path_put(&path); | |
518 | out: | |
519 | revert_creds(old_cred); | |
520 | put_cred(override_cred); | |
521 | return res; | |
522 | } | |
523 | ||
524 | SYSCALL_DEFINE2(access, const char __user *, filename, int, mode) | |
525 | { | |
526 | return sys_faccessat(AT_FDCWD, filename, mode); | |
527 | } | |
528 | ||
529 | SYSCALL_DEFINE1(chdir, const char __user *, filename) | |
530 | { | |
531 | struct path path; | |
532 | int error; | |
533 | ||
534 | error = user_path_dir(filename, &path); | |
535 | if (error) | |
536 | goto out; | |
537 | ||
538 | error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS); | |
539 | if (error) | |
540 | goto dput_and_out; | |
541 | ||
542 | set_fs_pwd(current->fs, &path); | |
543 | ||
544 | dput_and_out: | |
545 | path_put(&path); | |
546 | out: | |
547 | return error; | |
548 | } | |
549 | ||
550 | SYSCALL_DEFINE1(fchdir, unsigned int, fd) | |
551 | { | |
552 | struct file *file; | |
553 | struct inode *inode; | |
554 | int error; | |
555 | ||
556 | error = -EBADF; | |
557 | file = fget(fd); | |
558 | if (!file) | |
559 | goto out; | |
560 | ||
561 | inode = file->f_path.dentry->d_inode; | |
562 | ||
563 | error = -ENOTDIR; | |
564 | if (!S_ISDIR(inode->i_mode)) | |
565 | goto out_putf; | |
566 | ||
567 | error = inode_permission(inode, MAY_EXEC | MAY_ACCESS); | |
568 | if (!error) | |
569 | set_fs_pwd(current->fs, &file->f_path); | |
570 | out_putf: | |
571 | fput(file); | |
572 | out: | |
573 | return error; | |
574 | } | |
575 | ||
576 | SYSCALL_DEFINE1(chroot, const char __user *, filename) | |
577 | { | |
578 | struct path path; | |
579 | int error; | |
580 | ||
581 | error = user_path_dir(filename, &path); | |
582 | if (error) | |
583 | goto out; | |
584 | ||
585 | error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS); | |
586 | if (error) | |
587 | goto dput_and_out; | |
588 | ||
589 | error = -EPERM; | |
590 | if (!capable(CAP_SYS_CHROOT)) | |
591 | goto dput_and_out; | |
592 | error = security_path_chroot(&path); | |
593 | if (error) | |
594 | goto dput_and_out; | |
595 | ||
596 | set_fs_root(current->fs, &path); | |
597 | error = 0; | |
598 | dput_and_out: | |
599 | path_put(&path); | |
600 | out: | |
601 | return error; | |
602 | } | |
603 | ||
604 | SYSCALL_DEFINE2(fchmod, unsigned int, fd, mode_t, mode) | |
605 | { | |
606 | struct inode * inode; | |
607 | struct dentry * dentry; | |
608 | struct file * file; | |
609 | int err = -EBADF; | |
610 | struct iattr newattrs; | |
611 | ||
612 | file = fget(fd); | |
613 | if (!file) | |
614 | goto out; | |
615 | ||
616 | dentry = file->f_path.dentry; | |
617 | inode = dentry->d_inode; | |
618 | ||
619 | audit_inode(NULL, dentry); | |
620 | ||
621 | err = mnt_want_write_file(file); | |
622 | if (err) | |
623 | goto out_putf; | |
624 | mutex_lock(&inode->i_mutex); | |
625 | err = security_path_chmod(dentry, file->f_vfsmnt, mode); | |
626 | if (err) | |
627 | goto out_unlock; | |
628 | if (mode == (mode_t) -1) | |
629 | mode = inode->i_mode; | |
630 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); | |
631 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
632 | err = notify_change(dentry, &newattrs); | |
633 | out_unlock: | |
634 | mutex_unlock(&inode->i_mutex); | |
635 | mnt_drop_write(file->f_path.mnt); | |
636 | out_putf: | |
637 | fput(file); | |
638 | out: | |
639 | return err; | |
640 | } | |
641 | ||
642 | SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, mode_t, mode) | |
643 | { | |
644 | struct path path; | |
645 | struct inode *inode; | |
646 | int error; | |
647 | struct iattr newattrs; | |
648 | ||
649 | error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path); | |
650 | if (error) | |
651 | goto out; | |
652 | inode = path.dentry->d_inode; | |
653 | ||
654 | error = mnt_want_write(path.mnt); | |
655 | if (error) | |
656 | goto dput_and_out; | |
657 | mutex_lock(&inode->i_mutex); | |
658 | error = security_path_chmod(path.dentry, path.mnt, mode); | |
659 | if (error) | |
660 | goto out_unlock; | |
661 | if (mode == (mode_t) -1) | |
662 | mode = inode->i_mode; | |
663 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); | |
664 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
665 | error = notify_change(path.dentry, &newattrs); | |
666 | out_unlock: | |
667 | mutex_unlock(&inode->i_mutex); | |
668 | mnt_drop_write(path.mnt); | |
669 | dput_and_out: | |
670 | path_put(&path); | |
671 | out: | |
672 | return error; | |
673 | } | |
674 | ||
675 | SYSCALL_DEFINE2(chmod, const char __user *, filename, mode_t, mode) | |
676 | { | |
677 | return sys_fchmodat(AT_FDCWD, filename, mode); | |
678 | } | |
679 | ||
680 | static int chown_common(struct path *path, uid_t user, gid_t group) | |
681 | { | |
682 | struct inode *inode = path->dentry->d_inode; | |
683 | int error; | |
684 | struct iattr newattrs; | |
685 | ||
686 | newattrs.ia_valid = ATTR_CTIME; | |
687 | if (user != (uid_t) -1) { | |
688 | newattrs.ia_valid |= ATTR_UID; | |
689 | newattrs.ia_uid = user; | |
690 | } | |
691 | if (group != (gid_t) -1) { | |
692 | newattrs.ia_valid |= ATTR_GID; | |
693 | newattrs.ia_gid = group; | |
694 | } | |
695 | if (!S_ISDIR(inode->i_mode)) | |
696 | newattrs.ia_valid |= | |
697 | ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV; | |
698 | mutex_lock(&inode->i_mutex); | |
699 | error = security_path_chown(path, user, group); | |
700 | if (!error) | |
701 | error = notify_change(path->dentry, &newattrs); | |
702 | mutex_unlock(&inode->i_mutex); | |
703 | ||
704 | return error; | |
705 | } | |
706 | ||
707 | SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group) | |
708 | { | |
709 | struct path path; | |
710 | int error; | |
711 | ||
712 | error = user_path(filename, &path); | |
713 | if (error) | |
714 | goto out; | |
715 | error = mnt_want_write(path.mnt); | |
716 | if (error) | |
717 | goto out_release; | |
718 | error = chown_common(&path, user, group); | |
719 | mnt_drop_write(path.mnt); | |
720 | out_release: | |
721 | path_put(&path); | |
722 | out: | |
723 | return error; | |
724 | } | |
725 | ||
726 | SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user, | |
727 | gid_t, group, int, flag) | |
728 | { | |
729 | struct path path; | |
730 | int error = -EINVAL; | |
731 | int follow; | |
732 | ||
733 | if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) | |
734 | goto out; | |
735 | ||
736 | follow = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; | |
737 | error = user_path_at(dfd, filename, follow, &path); | |
738 | if (error) | |
739 | goto out; | |
740 | error = mnt_want_write(path.mnt); | |
741 | if (error) | |
742 | goto out_release; | |
743 | error = chown_common(&path, user, group); | |
744 | mnt_drop_write(path.mnt); | |
745 | out_release: | |
746 | path_put(&path); | |
747 | out: | |
748 | return error; | |
749 | } | |
750 | ||
751 | SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group) | |
752 | { | |
753 | struct path path; | |
754 | int error; | |
755 | ||
756 | error = user_lpath(filename, &path); | |
757 | if (error) | |
758 | goto out; | |
759 | error = mnt_want_write(path.mnt); | |
760 | if (error) | |
761 | goto out_release; | |
762 | error = chown_common(&path, user, group); | |
763 | mnt_drop_write(path.mnt); | |
764 | out_release: | |
765 | path_put(&path); | |
766 | out: | |
767 | return error; | |
768 | } | |
769 | ||
770 | SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group) | |
771 | { | |
772 | struct file * file; | |
773 | int error = -EBADF; | |
774 | struct dentry * dentry; | |
775 | ||
776 | file = fget(fd); | |
777 | if (!file) | |
778 | goto out; | |
779 | ||
780 | error = mnt_want_write_file(file); | |
781 | if (error) | |
782 | goto out_fput; | |
783 | dentry = file->f_path.dentry; | |
784 | audit_inode(NULL, dentry); | |
785 | error = chown_common(&file->f_path, user, group); | |
786 | mnt_drop_write(file->f_path.mnt); | |
787 | out_fput: | |
788 | fput(file); | |
789 | out: | |
790 | return error; | |
791 | } | |
792 | ||
793 | /* | |
794 | * You have to be very careful that these write | |
795 | * counts get cleaned up in error cases and | |
796 | * upon __fput(). This should probably never | |
797 | * be called outside of __dentry_open(). | |
798 | */ | |
799 | static inline int __get_file_write_access(struct inode *inode, | |
800 | struct vfsmount *mnt) | |
801 | { | |
802 | int error; | |
803 | error = get_write_access(inode); | |
804 | if (error) | |
805 | return error; | |
806 | /* | |
807 | * Do not take mount writer counts on | |
808 | * special files since no writes to | |
809 | * the mount itself will occur. | |
810 | */ | |
811 | if (!special_file(inode->i_mode)) { | |
812 | /* | |
813 | * Balanced in __fput() | |
814 | */ | |
815 | error = mnt_want_write(mnt); | |
816 | if (error) | |
817 | put_write_access(inode); | |
818 | } | |
819 | return error; | |
820 | } | |
821 | ||
822 | static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, | |
823 | int flags, struct file *f, | |
824 | int (*open)(struct inode *, struct file *), | |
825 | const struct cred *cred) | |
826 | { | |
827 | struct inode *inode; | |
828 | int error; | |
829 | ||
830 | f->f_flags = flags; | |
831 | f->f_mode = (__force fmode_t)((flags+1) & O_ACCMODE) | FMODE_LSEEK | | |
832 | FMODE_PREAD | FMODE_PWRITE; | |
833 | inode = dentry->d_inode; | |
834 | if (f->f_mode & FMODE_WRITE) { | |
835 | error = __get_file_write_access(inode, mnt); | |
836 | if (error) | |
837 | goto cleanup_file; | |
838 | if (!special_file(inode->i_mode)) | |
839 | file_take_write(f); | |
840 | } | |
841 | ||
842 | f->f_mapping = inode->i_mapping; | |
843 | f->f_path.dentry = dentry; | |
844 | f->f_path.mnt = mnt; | |
845 | f->f_pos = 0; | |
846 | f->f_op = fops_get(inode->i_fop); | |
847 | file_move(f, &inode->i_sb->s_files); | |
848 | ||
849 | error = security_dentry_open(f, cred); | |
850 | if (error) | |
851 | goto cleanup_all; | |
852 | ||
853 | if (!open && f->f_op) | |
854 | open = f->f_op->open; | |
855 | if (open) { | |
856 | error = open(inode, f); | |
857 | if (error) | |
858 | goto cleanup_all; | |
859 | } | |
860 | ||
861 | f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); | |
862 | ||
863 | file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); | |
864 | ||
865 | /* NB: we're sure to have correct a_ops only after f_op->open */ | |
866 | if (f->f_flags & O_DIRECT) { | |
867 | if (!f->f_mapping->a_ops || | |
868 | ((!f->f_mapping->a_ops->direct_IO) && | |
869 | (!f->f_mapping->a_ops->get_xip_mem))) { | |
870 | fput(f); | |
871 | f = ERR_PTR(-EINVAL); | |
872 | } | |
873 | } | |
874 | ||
875 | return f; | |
876 | ||
877 | cleanup_all: | |
878 | fops_put(f->f_op); | |
879 | if (f->f_mode & FMODE_WRITE) { | |
880 | put_write_access(inode); | |
881 | if (!special_file(inode->i_mode)) { | |
882 | /* | |
883 | * We don't consider this a real | |
884 | * mnt_want/drop_write() pair | |
885 | * because it all happenend right | |
886 | * here, so just reset the state. | |
887 | */ | |
888 | file_reset_write(f); | |
889 | mnt_drop_write(mnt); | |
890 | } | |
891 | } | |
892 | file_kill(f); | |
893 | f->f_path.dentry = NULL; | |
894 | f->f_path.mnt = NULL; | |
895 | cleanup_file: | |
896 | put_filp(f); | |
897 | dput(dentry); | |
898 | mntput(mnt); | |
899 | return ERR_PTR(error); | |
900 | } | |
901 | ||
902 | /** | |
903 | * lookup_instantiate_filp - instantiates the open intent filp | |
904 | * @nd: pointer to nameidata | |
905 | * @dentry: pointer to dentry | |
906 | * @open: open callback | |
907 | * | |
908 | * Helper for filesystems that want to use lookup open intents and pass back | |
909 | * a fully instantiated struct file to the caller. | |
910 | * This function is meant to be called from within a filesystem's | |
911 | * lookup method. | |
912 | * Beware of calling it for non-regular files! Those ->open methods might block | |
913 | * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo, | |
914 | * leading to a deadlock, as nobody can open that fifo anymore, because | |
915 | * another process to open fifo will block on locked parent when doing lookup). | |
916 | * Note that in case of error, nd->intent.open.file is destroyed, but the | |
917 | * path information remains valid. | |
918 | * If the open callback is set to NULL, then the standard f_op->open() | |
919 | * filesystem callback is substituted. | |
920 | */ | |
921 | struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry, | |
922 | int (*open)(struct inode *, struct file *)) | |
923 | { | |
924 | const struct cred *cred = current_cred(); | |
925 | ||
926 | if (IS_ERR(nd->intent.open.file)) | |
927 | goto out; | |
928 | if (IS_ERR(dentry)) | |
929 | goto out_err; | |
930 | nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt), | |
931 | nd->intent.open.flags - 1, | |
932 | nd->intent.open.file, | |
933 | open, cred); | |
934 | out: | |
935 | return nd->intent.open.file; | |
936 | out_err: | |
937 | release_open_intent(nd); | |
938 | nd->intent.open.file = (struct file *)dentry; | |
939 | goto out; | |
940 | } | |
941 | EXPORT_SYMBOL_GPL(lookup_instantiate_filp); | |
942 | ||
943 | /** | |
944 | * nameidata_to_filp - convert a nameidata to an open filp. | |
945 | * @nd: pointer to nameidata | |
946 | * @flags: open flags | |
947 | * | |
948 | * Note that this function destroys the original nameidata | |
949 | */ | |
950 | struct file *nameidata_to_filp(struct nameidata *nd, int flags) | |
951 | { | |
952 | const struct cred *cred = current_cred(); | |
953 | struct file *filp; | |
954 | ||
955 | /* Pick up the filp from the open intent */ | |
956 | filp = nd->intent.open.file; | |
957 | /* Has the filesystem initialised the file for us? */ | |
958 | if (filp->f_path.dentry == NULL) | |
959 | filp = __dentry_open(nd->path.dentry, nd->path.mnt, flags, filp, | |
960 | NULL, cred); | |
961 | else | |
962 | path_put(&nd->path); | |
963 | return filp; | |
964 | } | |
965 | ||
966 | /* | |
967 | * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an | |
968 | * error. | |
969 | */ | |
970 | struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags, | |
971 | const struct cred *cred) | |
972 | { | |
973 | int error; | |
974 | struct file *f; | |
975 | ||
976 | validate_creds(cred); | |
977 | ||
978 | /* | |
979 | * We must always pass in a valid mount pointer. Historically | |
980 | * callers got away with not passing it, but we must enforce this at | |
981 | * the earliest possible point now to avoid strange problems deep in the | |
982 | * filesystem stack. | |
983 | */ | |
984 | if (!mnt) { | |
985 | printk(KERN_WARNING "%s called with NULL vfsmount\n", __func__); | |
986 | dump_stack(); | |
987 | return ERR_PTR(-EINVAL); | |
988 | } | |
989 | ||
990 | error = -ENFILE; | |
991 | f = get_empty_filp(); | |
992 | if (f == NULL) { | |
993 | dput(dentry); | |
994 | mntput(mnt); | |
995 | return ERR_PTR(error); | |
996 | } | |
997 | ||
998 | return __dentry_open(dentry, mnt, flags, f, NULL, cred); | |
999 | } | |
1000 | EXPORT_SYMBOL(dentry_open); | |
1001 | ||
1002 | static void __put_unused_fd(struct files_struct *files, unsigned int fd) | |
1003 | { | |
1004 | struct fdtable *fdt = files_fdtable(files); | |
1005 | __FD_CLR(fd, fdt->open_fds); | |
1006 | if (fd < files->next_fd) | |
1007 | files->next_fd = fd; | |
1008 | } | |
1009 | ||
1010 | void put_unused_fd(unsigned int fd) | |
1011 | { | |
1012 | struct files_struct *files = current->files; | |
1013 | spin_lock(&files->file_lock); | |
1014 | __put_unused_fd(files, fd); | |
1015 | spin_unlock(&files->file_lock); | |
1016 | } | |
1017 | ||
1018 | EXPORT_SYMBOL(put_unused_fd); | |
1019 | ||
1020 | /* | |
1021 | * Install a file pointer in the fd array. | |
1022 | * | |
1023 | * The VFS is full of places where we drop the files lock between | |
1024 | * setting the open_fds bitmap and installing the file in the file | |
1025 | * array. At any such point, we are vulnerable to a dup2() race | |
1026 | * installing a file in the array before us. We need to detect this and | |
1027 | * fput() the struct file we are about to overwrite in this case. | |
1028 | * | |
1029 | * It should never happen - if we allow dup2() do it, _really_ bad things | |
1030 | * will follow. | |
1031 | */ | |
1032 | ||
1033 | void fd_install(unsigned int fd, struct file *file) | |
1034 | { | |
1035 | struct files_struct *files = current->files; | |
1036 | struct fdtable *fdt; | |
1037 | spin_lock(&files->file_lock); | |
1038 | fdt = files_fdtable(files); | |
1039 | BUG_ON(fdt->fd[fd] != NULL); | |
1040 | rcu_assign_pointer(fdt->fd[fd], file); | |
1041 | spin_unlock(&files->file_lock); | |
1042 | } | |
1043 | ||
1044 | EXPORT_SYMBOL(fd_install); | |
1045 | ||
1046 | long do_sys_open(int dfd, const char __user *filename, int flags, int mode) | |
1047 | { | |
1048 | char *tmp = getname(filename); | |
1049 | int fd = PTR_ERR(tmp); | |
1050 | ||
1051 | if (!IS_ERR(tmp)) { | |
1052 | fd = get_unused_fd_flags(flags); | |
1053 | if (fd >= 0) { | |
1054 | struct file *f = do_filp_open(dfd, tmp, flags, mode, 0); | |
1055 | if (IS_ERR(f)) { | |
1056 | put_unused_fd(fd); | |
1057 | fd = PTR_ERR(f); | |
1058 | } else { | |
1059 | fsnotify_open(f->f_path.dentry); | |
1060 | fd_install(fd, f); | |
1061 | } | |
1062 | } | |
1063 | putname(tmp); | |
1064 | } | |
1065 | return fd; | |
1066 | } | |
1067 | ||
1068 | SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, int, mode) | |
1069 | { | |
1070 | long ret; | |
1071 | ||
1072 | if (force_o_largefile()) | |
1073 | flags |= O_LARGEFILE; | |
1074 | ||
1075 | ret = do_sys_open(AT_FDCWD, filename, flags, mode); | |
1076 | /* avoid REGPARM breakage on x86: */ | |
1077 | asmlinkage_protect(3, ret, filename, flags, mode); | |
1078 | return ret; | |
1079 | } | |
1080 | ||
1081 | SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, | |
1082 | int, mode) | |
1083 | { | |
1084 | long ret; | |
1085 | ||
1086 | if (force_o_largefile()) | |
1087 | flags |= O_LARGEFILE; | |
1088 | ||
1089 | ret = do_sys_open(dfd, filename, flags, mode); | |
1090 | /* avoid REGPARM breakage on x86: */ | |
1091 | asmlinkage_protect(4, ret, dfd, filename, flags, mode); | |
1092 | return ret; | |
1093 | } | |
1094 | ||
1095 | #ifndef __alpha__ | |
1096 | ||
1097 | /* | |
1098 | * For backward compatibility? Maybe this should be moved | |
1099 | * into arch/i386 instead? | |
1100 | */ | |
1101 | SYSCALL_DEFINE2(creat, const char __user *, pathname, int, mode) | |
1102 | { | |
1103 | return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); | |
1104 | } | |
1105 | ||
1106 | #endif | |
1107 | ||
1108 | /* | |
1109 | * "id" is the POSIX thread ID. We use the | |
1110 | * files pointer for this.. | |
1111 | */ | |
1112 | int filp_close(struct file *filp, fl_owner_t id) | |
1113 | { | |
1114 | int retval = 0; | |
1115 | ||
1116 | if (!file_count(filp)) { | |
1117 | printk(KERN_ERR "VFS: Close: file count is 0\n"); | |
1118 | return 0; | |
1119 | } | |
1120 | ||
1121 | if (filp->f_op && filp->f_op->flush) | |
1122 | retval = filp->f_op->flush(filp, id); | |
1123 | ||
1124 | dnotify_flush(filp, id); | |
1125 | locks_remove_posix(filp, id); | |
1126 | fput(filp); | |
1127 | return retval; | |
1128 | } | |
1129 | ||
1130 | EXPORT_SYMBOL(filp_close); | |
1131 | ||
1132 | /* | |
1133 | * Careful here! We test whether the file pointer is NULL before | |
1134 | * releasing the fd. This ensures that one clone task can't release | |
1135 | * an fd while another clone is opening it. | |
1136 | */ | |
1137 | SYSCALL_DEFINE1(close, unsigned int, fd) | |
1138 | { | |
1139 | struct file * filp; | |
1140 | struct files_struct *files = current->files; | |
1141 | struct fdtable *fdt; | |
1142 | int retval; | |
1143 | ||
1144 | spin_lock(&files->file_lock); | |
1145 | fdt = files_fdtable(files); | |
1146 | if (fd >= fdt->max_fds) | |
1147 | goto out_unlock; | |
1148 | filp = fdt->fd[fd]; | |
1149 | if (!filp) | |
1150 | goto out_unlock; | |
1151 | rcu_assign_pointer(fdt->fd[fd], NULL); | |
1152 | FD_CLR(fd, fdt->close_on_exec); | |
1153 | __put_unused_fd(files, fd); | |
1154 | spin_unlock(&files->file_lock); | |
1155 | retval = filp_close(filp, files); | |
1156 | ||
1157 | /* can't restart close syscall because file table entry was cleared */ | |
1158 | if (unlikely(retval == -ERESTARTSYS || | |
1159 | retval == -ERESTARTNOINTR || | |
1160 | retval == -ERESTARTNOHAND || | |
1161 | retval == -ERESTART_RESTARTBLOCK)) | |
1162 | retval = -EINTR; | |
1163 | ||
1164 | return retval; | |
1165 | ||
1166 | out_unlock: | |
1167 | spin_unlock(&files->file_lock); | |
1168 | return -EBADF; | |
1169 | } | |
1170 | EXPORT_SYMBOL(sys_close); | |
1171 | ||
1172 | /* | |
1173 | * This routine simulates a hangup on the tty, to arrange that users | |
1174 | * are given clean terminals at login time. | |
1175 | */ | |
1176 | SYSCALL_DEFINE0(vhangup) | |
1177 | { | |
1178 | if (capable(CAP_SYS_TTY_CONFIG)) { | |
1179 | tty_vhangup_self(); | |
1180 | return 0; | |
1181 | } | |
1182 | return -EPERM; | |
1183 | } | |
1184 | ||
1185 | /* | |
1186 | * Called when an inode is about to be open. | |
1187 | * We use this to disallow opening large files on 32bit systems if | |
1188 | * the caller didn't specify O_LARGEFILE. On 64bit systems we force | |
1189 | * on this flag in sys_open. | |
1190 | */ | |
1191 | int generic_file_open(struct inode * inode, struct file * filp) | |
1192 | { | |
1193 | if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) | |
1194 | return -EOVERFLOW; | |
1195 | return 0; | |
1196 | } | |
1197 | ||
1198 | EXPORT_SYMBOL(generic_file_open); | |
1199 | ||
1200 | /* | |
1201 | * This is used by subsystems that don't want seekable | |
1202 | * file descriptors | |
1203 | */ | |
1204 | int nonseekable_open(struct inode *inode, struct file *filp) | |
1205 | { | |
1206 | filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); | |
1207 | return 0; | |
1208 | } | |
1209 | ||
1210 | EXPORT_SYMBOL(nonseekable_open); |