Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/namei.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * Some corrections by tytso. | |
9 | */ | |
10 | ||
11 | /* [Feb 1997 T. Schoebel-Theuer] Complete rewrite of the pathname | |
12 | * lookup logic. | |
13 | */ | |
14 | /* [Feb-Apr 2000, AV] Rewrite to the new namespace architecture. | |
15 | */ | |
16 | ||
17 | #include <linux/init.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/namei.h> | |
22 | #include <linux/quotaops.h> | |
23 | #include <linux/pagemap.h> | |
0eeca283 | 24 | #include <linux/fsnotify.h> |
1da177e4 LT |
25 | #include <linux/personality.h> |
26 | #include <linux/security.h> | |
6146f0d5 | 27 | #include <linux/ima.h> |
1da177e4 LT |
28 | #include <linux/syscalls.h> |
29 | #include <linux/mount.h> | |
30 | #include <linux/audit.h> | |
16f7e0fe | 31 | #include <linux/capability.h> |
834f2a4a | 32 | #include <linux/file.h> |
5590ff0d | 33 | #include <linux/fcntl.h> |
08ce5f16 | 34 | #include <linux/device_cgroup.h> |
5ad4e53b | 35 | #include <linux/fs_struct.h> |
1da177e4 LT |
36 | #include <asm/uaccess.h> |
37 | ||
38 | #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE]) | |
39 | ||
40 | /* [Feb-1997 T. Schoebel-Theuer] | |
41 | * Fundamental changes in the pathname lookup mechanisms (namei) | |
42 | * were necessary because of omirr. The reason is that omirr needs | |
43 | * to know the _real_ pathname, not the user-supplied one, in case | |
44 | * of symlinks (and also when transname replacements occur). | |
45 | * | |
46 | * The new code replaces the old recursive symlink resolution with | |
47 | * an iterative one (in case of non-nested symlink chains). It does | |
48 | * this with calls to <fs>_follow_link(). | |
49 | * As a side effect, dir_namei(), _namei() and follow_link() are now | |
50 | * replaced with a single function lookup_dentry() that can handle all | |
51 | * the special cases of the former code. | |
52 | * | |
53 | * With the new dcache, the pathname is stored at each inode, at least as | |
54 | * long as the refcount of the inode is positive. As a side effect, the | |
55 | * size of the dcache depends on the inode cache and thus is dynamic. | |
56 | * | |
57 | * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink | |
58 | * resolution to correspond with current state of the code. | |
59 | * | |
60 | * Note that the symlink resolution is not *completely* iterative. | |
61 | * There is still a significant amount of tail- and mid- recursion in | |
62 | * the algorithm. Also, note that <fs>_readlink() is not used in | |
63 | * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink() | |
64 | * may return different results than <fs>_follow_link(). Many virtual | |
65 | * filesystems (including /proc) exhibit this behavior. | |
66 | */ | |
67 | ||
68 | /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation: | |
69 | * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL | |
70 | * and the name already exists in form of a symlink, try to create the new | |
71 | * name indicated by the symlink. The old code always complained that the | |
72 | * name already exists, due to not following the symlink even if its target | |
73 | * is nonexistent. The new semantics affects also mknod() and link() when | |
74 | * the name is a symlink pointing to a non-existant name. | |
75 | * | |
76 | * I don't know which semantics is the right one, since I have no access | |
77 | * to standards. But I found by trial that HP-UX 9.0 has the full "new" | |
78 | * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the | |
79 | * "old" one. Personally, I think the new semantics is much more logical. | |
80 | * Note that "ln old new" where "new" is a symlink pointing to a non-existing | |
81 | * file does succeed in both HP-UX and SunOs, but not in Solaris | |
82 | * and in the old Linux semantics. | |
83 | */ | |
84 | ||
85 | /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink | |
86 | * semantics. See the comments in "open_namei" and "do_link" below. | |
87 | * | |
88 | * [10-Sep-98 Alan Modra] Another symlink change. | |
89 | */ | |
90 | ||
91 | /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks: | |
92 | * inside the path - always follow. | |
93 | * in the last component in creation/removal/renaming - never follow. | |
94 | * if LOOKUP_FOLLOW passed - follow. | |
95 | * if the pathname has trailing slashes - follow. | |
96 | * otherwise - don't follow. | |
97 | * (applied in that order). | |
98 | * | |
99 | * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT | |
100 | * restored for 2.4. This is the last surviving part of old 4.2BSD bug. | |
101 | * During the 2.4 we need to fix the userland stuff depending on it - | |
102 | * hopefully we will be able to get rid of that wart in 2.5. So far only | |
103 | * XEmacs seems to be relying on it... | |
104 | */ | |
105 | /* | |
106 | * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland) | |
a11f3a05 | 107 | * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives |
1da177e4 LT |
108 | * any extra contention... |
109 | */ | |
110 | ||
a02f76c3 | 111 | static int __link_path_walk(const char *name, struct nameidata *nd); |
c4a7808f | 112 | |
1da177e4 LT |
113 | /* In order to reduce some races, while at the same time doing additional |
114 | * checking and hopefully speeding things up, we copy filenames to the | |
115 | * kernel data space before using them.. | |
116 | * | |
117 | * POSIX.1 2.4: an empty pathname is invalid (ENOENT). | |
118 | * PATH_MAX includes the nul terminator --RR. | |
119 | */ | |
858119e1 | 120 | static int do_getname(const char __user *filename, char *page) |
1da177e4 LT |
121 | { |
122 | int retval; | |
123 | unsigned long len = PATH_MAX; | |
124 | ||
125 | if (!segment_eq(get_fs(), KERNEL_DS)) { | |
126 | if ((unsigned long) filename >= TASK_SIZE) | |
127 | return -EFAULT; | |
128 | if (TASK_SIZE - (unsigned long) filename < PATH_MAX) | |
129 | len = TASK_SIZE - (unsigned long) filename; | |
130 | } | |
131 | ||
132 | retval = strncpy_from_user(page, filename, len); | |
133 | if (retval > 0) { | |
134 | if (retval < len) | |
135 | return 0; | |
136 | return -ENAMETOOLONG; | |
137 | } else if (!retval) | |
138 | retval = -ENOENT; | |
139 | return retval; | |
140 | } | |
141 | ||
142 | char * getname(const char __user * filename) | |
143 | { | |
144 | char *tmp, *result; | |
145 | ||
146 | result = ERR_PTR(-ENOMEM); | |
147 | tmp = __getname(); | |
148 | if (tmp) { | |
149 | int retval = do_getname(filename, tmp); | |
150 | ||
151 | result = tmp; | |
152 | if (retval < 0) { | |
153 | __putname(tmp); | |
154 | result = ERR_PTR(retval); | |
155 | } | |
156 | } | |
157 | audit_getname(result); | |
158 | return result; | |
159 | } | |
160 | ||
161 | #ifdef CONFIG_AUDITSYSCALL | |
162 | void putname(const char *name) | |
163 | { | |
5ac3a9c2 | 164 | if (unlikely(!audit_dummy_context())) |
1da177e4 LT |
165 | audit_putname(name); |
166 | else | |
167 | __putname(name); | |
168 | } | |
169 | EXPORT_SYMBOL(putname); | |
170 | #endif | |
171 | ||
172 | ||
173 | /** | |
174 | * generic_permission - check for access rights on a Posix-like filesystem | |
175 | * @inode: inode to check access rights for | |
176 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) | |
177 | * @check_acl: optional callback to check for Posix ACLs | |
178 | * | |
179 | * Used to check for read/write/execute permissions on a file. | |
180 | * We use "fsuid" for this, letting us set arbitrary permissions | |
181 | * for filesystem access without changing the "normal" uids which | |
182 | * are used for other things.. | |
183 | */ | |
184 | int generic_permission(struct inode *inode, int mask, | |
185 | int (*check_acl)(struct inode *inode, int mask)) | |
186 | { | |
187 | umode_t mode = inode->i_mode; | |
188 | ||
e6305c43 AV |
189 | mask &= MAY_READ | MAY_WRITE | MAY_EXEC; |
190 | ||
da9592ed | 191 | if (current_fsuid() == inode->i_uid) |
1da177e4 LT |
192 | mode >>= 6; |
193 | else { | |
194 | if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) { | |
195 | int error = check_acl(inode, mask); | |
196 | if (error == -EACCES) | |
197 | goto check_capabilities; | |
198 | else if (error != -EAGAIN) | |
199 | return error; | |
200 | } | |
201 | ||
202 | if (in_group_p(inode->i_gid)) | |
203 | mode >>= 3; | |
204 | } | |
205 | ||
206 | /* | |
207 | * If the DACs are ok we don't need any capability check. | |
208 | */ | |
e6305c43 | 209 | if ((mask & ~mode) == 0) |
1da177e4 LT |
210 | return 0; |
211 | ||
212 | check_capabilities: | |
213 | /* | |
214 | * Read/write DACs are always overridable. | |
215 | * Executable DACs are overridable if at least one exec bit is set. | |
216 | */ | |
f696a365 | 217 | if (!(mask & MAY_EXEC) || execute_ok(inode)) |
1da177e4 LT |
218 | if (capable(CAP_DAC_OVERRIDE)) |
219 | return 0; | |
220 | ||
221 | /* | |
222 | * Searching includes executable on directories, else just read. | |
223 | */ | |
224 | if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) | |
225 | if (capable(CAP_DAC_READ_SEARCH)) | |
226 | return 0; | |
227 | ||
228 | return -EACCES; | |
229 | } | |
230 | ||
cb23beb5 CH |
231 | /** |
232 | * inode_permission - check for access rights to a given inode | |
233 | * @inode: inode to check permission on | |
234 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) | |
235 | * | |
236 | * Used to check for read/write/execute permissions on an inode. | |
237 | * We use "fsuid" for this, letting us set arbitrary permissions | |
238 | * for filesystem access without changing the "normal" uids which | |
239 | * are used for other things. | |
240 | */ | |
f419a2e3 | 241 | int inode_permission(struct inode *inode, int mask) |
1da177e4 | 242 | { |
e6305c43 | 243 | int retval; |
1da177e4 LT |
244 | |
245 | if (mask & MAY_WRITE) { | |
22590e41 | 246 | umode_t mode = inode->i_mode; |
1da177e4 LT |
247 | |
248 | /* | |
249 | * Nobody gets write access to a read-only fs. | |
250 | */ | |
251 | if (IS_RDONLY(inode) && | |
252 | (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) | |
253 | return -EROFS; | |
254 | ||
255 | /* | |
256 | * Nobody gets write access to an immutable file. | |
257 | */ | |
258 | if (IS_IMMUTABLE(inode)) | |
259 | return -EACCES; | |
260 | } | |
261 | ||
acfa4380 | 262 | if (inode->i_op->permission) |
b77b0646 | 263 | retval = inode->i_op->permission(inode, mask); |
f696a365 | 264 | else |
e6305c43 | 265 | retval = generic_permission(inode, mask, NULL); |
f696a365 | 266 | |
1da177e4 LT |
267 | if (retval) |
268 | return retval; | |
269 | ||
08ce5f16 SH |
270 | retval = devcgroup_inode_permission(inode, mask); |
271 | if (retval) | |
272 | return retval; | |
273 | ||
e6305c43 | 274 | return security_inode_permission(inode, |
f418b006 | 275 | mask & (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND)); |
1da177e4 LT |
276 | } |
277 | ||
8c744fb8 CH |
278 | /** |
279 | * file_permission - check for additional access rights to a given file | |
280 | * @file: file to check access rights for | |
281 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) | |
282 | * | |
283 | * Used to check for read/write/execute permissions on an already opened | |
284 | * file. | |
285 | * | |
286 | * Note: | |
287 | * Do not use this function in new code. All access checks should | |
cb23beb5 | 288 | * be done using inode_permission(). |
8c744fb8 CH |
289 | */ |
290 | int file_permission(struct file *file, int mask) | |
291 | { | |
f419a2e3 | 292 | return inode_permission(file->f_path.dentry->d_inode, mask); |
8c744fb8 CH |
293 | } |
294 | ||
1da177e4 LT |
295 | /* |
296 | * get_write_access() gets write permission for a file. | |
297 | * put_write_access() releases this write permission. | |
298 | * This is used for regular files. | |
299 | * We cannot support write (and maybe mmap read-write shared) accesses and | |
300 | * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode | |
301 | * can have the following values: | |
302 | * 0: no writers, no VM_DENYWRITE mappings | |
303 | * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist | |
304 | * > 0: (i_writecount) users are writing to the file. | |
305 | * | |
306 | * Normally we operate on that counter with atomic_{inc,dec} and it's safe | |
307 | * except for the cases where we don't hold i_writecount yet. Then we need to | |
308 | * use {get,deny}_write_access() - these functions check the sign and refuse | |
309 | * to do the change if sign is wrong. Exclusion between them is provided by | |
310 | * the inode->i_lock spinlock. | |
311 | */ | |
312 | ||
313 | int get_write_access(struct inode * inode) | |
314 | { | |
315 | spin_lock(&inode->i_lock); | |
316 | if (atomic_read(&inode->i_writecount) < 0) { | |
317 | spin_unlock(&inode->i_lock); | |
318 | return -ETXTBSY; | |
319 | } | |
320 | atomic_inc(&inode->i_writecount); | |
321 | spin_unlock(&inode->i_lock); | |
322 | ||
323 | return 0; | |
324 | } | |
325 | ||
326 | int deny_write_access(struct file * file) | |
327 | { | |
0f7fc9e4 | 328 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
329 | |
330 | spin_lock(&inode->i_lock); | |
331 | if (atomic_read(&inode->i_writecount) > 0) { | |
332 | spin_unlock(&inode->i_lock); | |
333 | return -ETXTBSY; | |
334 | } | |
335 | atomic_dec(&inode->i_writecount); | |
336 | spin_unlock(&inode->i_lock); | |
337 | ||
338 | return 0; | |
339 | } | |
340 | ||
5dd784d0 JB |
341 | /** |
342 | * path_get - get a reference to a path | |
343 | * @path: path to get the reference to | |
344 | * | |
345 | * Given a path increment the reference count to the dentry and the vfsmount. | |
346 | */ | |
347 | void path_get(struct path *path) | |
348 | { | |
349 | mntget(path->mnt); | |
350 | dget(path->dentry); | |
351 | } | |
352 | EXPORT_SYMBOL(path_get); | |
353 | ||
1d957f9b JB |
354 | /** |
355 | * path_put - put a reference to a path | |
356 | * @path: path to put the reference to | |
357 | * | |
358 | * Given a path decrement the reference count to the dentry and the vfsmount. | |
359 | */ | |
360 | void path_put(struct path *path) | |
1da177e4 | 361 | { |
1d957f9b JB |
362 | dput(path->dentry); |
363 | mntput(path->mnt); | |
1da177e4 | 364 | } |
1d957f9b | 365 | EXPORT_SYMBOL(path_put); |
1da177e4 | 366 | |
834f2a4a TM |
367 | /** |
368 | * release_open_intent - free up open intent resources | |
369 | * @nd: pointer to nameidata | |
370 | */ | |
371 | void release_open_intent(struct nameidata *nd) | |
372 | { | |
0f7fc9e4 | 373 | if (nd->intent.open.file->f_path.dentry == NULL) |
834f2a4a TM |
374 | put_filp(nd->intent.open.file); |
375 | else | |
376 | fput(nd->intent.open.file); | |
377 | } | |
378 | ||
bcdc5e01 IK |
379 | static inline struct dentry * |
380 | do_revalidate(struct dentry *dentry, struct nameidata *nd) | |
381 | { | |
382 | int status = dentry->d_op->d_revalidate(dentry, nd); | |
383 | if (unlikely(status <= 0)) { | |
384 | /* | |
385 | * The dentry failed validation. | |
386 | * If d_revalidate returned 0 attempt to invalidate | |
387 | * the dentry otherwise d_revalidate is asking us | |
388 | * to return a fail status. | |
389 | */ | |
390 | if (!status) { | |
391 | if (!d_invalidate(dentry)) { | |
392 | dput(dentry); | |
393 | dentry = NULL; | |
394 | } | |
395 | } else { | |
396 | dput(dentry); | |
397 | dentry = ERR_PTR(status); | |
398 | } | |
399 | } | |
400 | return dentry; | |
401 | } | |
402 | ||
1da177e4 LT |
403 | /* |
404 | * Internal lookup() using the new generic dcache. | |
405 | * SMP-safe | |
406 | */ | |
407 | static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) | |
408 | { | |
409 | struct dentry * dentry = __d_lookup(parent, name); | |
410 | ||
411 | /* lockess __d_lookup may fail due to concurrent d_move() | |
412 | * in some unrelated directory, so try with d_lookup | |
413 | */ | |
414 | if (!dentry) | |
415 | dentry = d_lookup(parent, name); | |
416 | ||
bcdc5e01 IK |
417 | if (dentry && dentry->d_op && dentry->d_op->d_revalidate) |
418 | dentry = do_revalidate(dentry, nd); | |
419 | ||
1da177e4 LT |
420 | return dentry; |
421 | } | |
422 | ||
423 | /* | |
424 | * Short-cut version of permission(), for calling by | |
425 | * path_walk(), when dcache lock is held. Combines parts | |
426 | * of permission() and generic_permission(), and tests ONLY for | |
427 | * MAY_EXEC permission. | |
428 | * | |
429 | * If appropriate, check DAC only. If not appropriate, or | |
430 | * short-cut DAC fails, then call permission() to do more | |
431 | * complete permission check. | |
432 | */ | |
672b16b2 | 433 | static int exec_permission_lite(struct inode *inode) |
1da177e4 LT |
434 | { |
435 | umode_t mode = inode->i_mode; | |
436 | ||
cb9179ea LT |
437 | if (inode->i_op->permission) { |
438 | int ret = inode->i_op->permission(inode, MAY_EXEC); | |
439 | if (!ret) | |
440 | goto ok; | |
441 | return ret; | |
442 | } | |
1da177e4 | 443 | |
da9592ed | 444 | if (current_fsuid() == inode->i_uid) |
1da177e4 LT |
445 | mode >>= 6; |
446 | else if (in_group_p(inode->i_gid)) | |
447 | mode >>= 3; | |
448 | ||
449 | if (mode & MAY_EXEC) | |
450 | goto ok; | |
451 | ||
f1ac9f6b | 452 | if (capable(CAP_DAC_OVERRIDE) || capable(CAP_DAC_READ_SEARCH)) |
1da177e4 LT |
453 | goto ok; |
454 | ||
455 | return -EACCES; | |
456 | ok: | |
b77b0646 | 457 | return security_inode_permission(inode, MAY_EXEC); |
1da177e4 LT |
458 | } |
459 | ||
460 | /* | |
461 | * This is called when everything else fails, and we actually have | |
462 | * to go to the low-level filesystem to find out what we should do.. | |
463 | * | |
464 | * We get the directory semaphore, and after getting that we also | |
465 | * make sure that nobody added the entry to the dcache in the meantime.. | |
466 | * SMP-safe | |
467 | */ | |
468 | static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) | |
469 | { | |
470 | struct dentry * result; | |
471 | struct inode *dir = parent->d_inode; | |
472 | ||
1b1dcc1b | 473 | mutex_lock(&dir->i_mutex); |
1da177e4 LT |
474 | /* |
475 | * First re-do the cached lookup just in case it was created | |
476 | * while we waited for the directory semaphore.. | |
477 | * | |
478 | * FIXME! This could use version numbering or similar to | |
479 | * avoid unnecessary cache lookups. | |
480 | * | |
481 | * The "dcache_lock" is purely to protect the RCU list walker | |
482 | * from concurrent renames at this point (we mustn't get false | |
483 | * negatives from the RCU list walk here, unlike the optimistic | |
484 | * fast walk). | |
485 | * | |
486 | * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup | |
487 | */ | |
488 | result = d_lookup(parent, name); | |
489 | if (!result) { | |
d70b67c8 MS |
490 | struct dentry *dentry; |
491 | ||
492 | /* Don't create child dentry for a dead directory. */ | |
493 | result = ERR_PTR(-ENOENT); | |
494 | if (IS_DEADDIR(dir)) | |
495 | goto out_unlock; | |
496 | ||
497 | dentry = d_alloc(parent, name); | |
1da177e4 LT |
498 | result = ERR_PTR(-ENOMEM); |
499 | if (dentry) { | |
500 | result = dir->i_op->lookup(dir, dentry, nd); | |
501 | if (result) | |
502 | dput(dentry); | |
503 | else | |
504 | result = dentry; | |
505 | } | |
d70b67c8 | 506 | out_unlock: |
1b1dcc1b | 507 | mutex_unlock(&dir->i_mutex); |
1da177e4 LT |
508 | return result; |
509 | } | |
510 | ||
511 | /* | |
512 | * Uhhuh! Nasty case: the cache was re-populated while | |
513 | * we waited on the semaphore. Need to revalidate. | |
514 | */ | |
1b1dcc1b | 515 | mutex_unlock(&dir->i_mutex); |
1da177e4 | 516 | if (result->d_op && result->d_op->d_revalidate) { |
bcdc5e01 IK |
517 | result = do_revalidate(result, nd); |
518 | if (!result) | |
1da177e4 | 519 | result = ERR_PTR(-ENOENT); |
1da177e4 LT |
520 | } |
521 | return result; | |
522 | } | |
523 | ||
a02f76c3 AV |
524 | /* |
525 | * Wrapper to retry pathname resolution whenever the underlying | |
526 | * file system returns an ESTALE. | |
527 | * | |
528 | * Retry the whole path once, forcing real lookup requests | |
529 | * instead of relying on the dcache. | |
530 | */ | |
531 | static __always_inline int link_path_walk(const char *name, struct nameidata *nd) | |
532 | { | |
533 | struct path save = nd->path; | |
534 | int result; | |
535 | ||
536 | /* make sure the stuff we saved doesn't go away */ | |
c8e7f449 | 537 | path_get(&save); |
a02f76c3 AV |
538 | |
539 | result = __link_path_walk(name, nd); | |
540 | if (result == -ESTALE) { | |
541 | /* nd->path had been dropped */ | |
542 | nd->path = save; | |
c8e7f449 | 543 | path_get(&nd->path); |
a02f76c3 AV |
544 | nd->flags |= LOOKUP_REVAL; |
545 | result = __link_path_walk(name, nd); | |
546 | } | |
547 | ||
548 | path_put(&save); | |
549 | ||
550 | return result; | |
551 | } | |
552 | ||
2a737871 AV |
553 | static __always_inline void set_root(struct nameidata *nd) |
554 | { | |
555 | if (!nd->root.mnt) { | |
556 | struct fs_struct *fs = current->fs; | |
557 | read_lock(&fs->lock); | |
558 | nd->root = fs->root; | |
559 | path_get(&nd->root); | |
560 | read_unlock(&fs->lock); | |
561 | } | |
562 | } | |
563 | ||
f1662356 | 564 | static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) |
1da177e4 LT |
565 | { |
566 | int res = 0; | |
567 | char *name; | |
568 | if (IS_ERR(link)) | |
569 | goto fail; | |
570 | ||
571 | if (*link == '/') { | |
2a737871 | 572 | set_root(nd); |
1d957f9b | 573 | path_put(&nd->path); |
2a737871 AV |
574 | nd->path = nd->root; |
575 | path_get(&nd->root); | |
1da177e4 | 576 | } |
b4091d5f | 577 | |
1da177e4 | 578 | res = link_path_walk(link, nd); |
1da177e4 LT |
579 | if (nd->depth || res || nd->last_type!=LAST_NORM) |
580 | return res; | |
581 | /* | |
582 | * If it is an iterative symlinks resolution in open_namei() we | |
583 | * have to copy the last component. And all that crap because of | |
584 | * bloody create() on broken symlinks. Furrfu... | |
585 | */ | |
586 | name = __getname(); | |
587 | if (unlikely(!name)) { | |
1d957f9b | 588 | path_put(&nd->path); |
1da177e4 LT |
589 | return -ENOMEM; |
590 | } | |
591 | strcpy(name, nd->last.name); | |
592 | nd->last.name = name; | |
593 | return 0; | |
594 | fail: | |
1d957f9b | 595 | path_put(&nd->path); |
1da177e4 LT |
596 | return PTR_ERR(link); |
597 | } | |
598 | ||
1d957f9b | 599 | static void path_put_conditional(struct path *path, struct nameidata *nd) |
051d3812 IK |
600 | { |
601 | dput(path->dentry); | |
4ac91378 | 602 | if (path->mnt != nd->path.mnt) |
051d3812 IK |
603 | mntput(path->mnt); |
604 | } | |
605 | ||
606 | static inline void path_to_nameidata(struct path *path, struct nameidata *nd) | |
607 | { | |
4ac91378 JB |
608 | dput(nd->path.dentry); |
609 | if (nd->path.mnt != path->mnt) | |
610 | mntput(nd->path.mnt); | |
611 | nd->path.mnt = path->mnt; | |
612 | nd->path.dentry = path->dentry; | |
051d3812 IK |
613 | } |
614 | ||
f1662356 | 615 | static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd) |
1da177e4 LT |
616 | { |
617 | int error; | |
cc314eef | 618 | void *cookie; |
cd4e91d3 | 619 | struct dentry *dentry = path->dentry; |
1da177e4 | 620 | |
d671a1cb | 621 | touch_atime(path->mnt, dentry); |
1da177e4 | 622 | nd_set_link(nd, NULL); |
cd4e91d3 | 623 | |
4ac91378 | 624 | if (path->mnt != nd->path.mnt) { |
051d3812 IK |
625 | path_to_nameidata(path, nd); |
626 | dget(dentry); | |
627 | } | |
628 | mntget(path->mnt); | |
cc314eef LT |
629 | cookie = dentry->d_inode->i_op->follow_link(dentry, nd); |
630 | error = PTR_ERR(cookie); | |
631 | if (!IS_ERR(cookie)) { | |
1da177e4 | 632 | char *s = nd_get_link(nd); |
cc314eef | 633 | error = 0; |
1da177e4 LT |
634 | if (s) |
635 | error = __vfs_follow_link(nd, s); | |
636 | if (dentry->d_inode->i_op->put_link) | |
cc314eef | 637 | dentry->d_inode->i_op->put_link(dentry, nd, cookie); |
1da177e4 | 638 | } |
09da5916 | 639 | path_put(path); |
1da177e4 LT |
640 | |
641 | return error; | |
642 | } | |
643 | ||
644 | /* | |
645 | * This limits recursive symlink follows to 8, while | |
646 | * limiting consecutive symlinks to 40. | |
647 | * | |
648 | * Without that kind of total limit, nasty chains of consecutive | |
649 | * symlinks can cause almost arbitrarily long lookups. | |
650 | */ | |
90ebe565 | 651 | static inline int do_follow_link(struct path *path, struct nameidata *nd) |
1da177e4 LT |
652 | { |
653 | int err = -ELOOP; | |
654 | if (current->link_count >= MAX_NESTED_LINKS) | |
655 | goto loop; | |
656 | if (current->total_link_count >= 40) | |
657 | goto loop; | |
658 | BUG_ON(nd->depth >= MAX_NESTED_LINKS); | |
659 | cond_resched(); | |
90ebe565 | 660 | err = security_inode_follow_link(path->dentry, nd); |
1da177e4 LT |
661 | if (err) |
662 | goto loop; | |
663 | current->link_count++; | |
664 | current->total_link_count++; | |
665 | nd->depth++; | |
cd4e91d3 | 666 | err = __do_follow_link(path, nd); |
839d9f93 AV |
667 | current->link_count--; |
668 | nd->depth--; | |
1da177e4 LT |
669 | return err; |
670 | loop: | |
1d957f9b JB |
671 | path_put_conditional(path, nd); |
672 | path_put(&nd->path); | |
1da177e4 LT |
673 | return err; |
674 | } | |
675 | ||
bab77ebf | 676 | int follow_up(struct path *path) |
1da177e4 LT |
677 | { |
678 | struct vfsmount *parent; | |
679 | struct dentry *mountpoint; | |
680 | spin_lock(&vfsmount_lock); | |
bab77ebf AV |
681 | parent = path->mnt->mnt_parent; |
682 | if (parent == path->mnt) { | |
1da177e4 LT |
683 | spin_unlock(&vfsmount_lock); |
684 | return 0; | |
685 | } | |
686 | mntget(parent); | |
bab77ebf | 687 | mountpoint = dget(path->mnt->mnt_mountpoint); |
1da177e4 | 688 | spin_unlock(&vfsmount_lock); |
bab77ebf AV |
689 | dput(path->dentry); |
690 | path->dentry = mountpoint; | |
691 | mntput(path->mnt); | |
692 | path->mnt = parent; | |
1da177e4 LT |
693 | return 1; |
694 | } | |
695 | ||
696 | /* no need for dcache_lock, as serialization is taken care in | |
697 | * namespace.c | |
698 | */ | |
463ffb2e AV |
699 | static int __follow_mount(struct path *path) |
700 | { | |
701 | int res = 0; | |
702 | while (d_mountpoint(path->dentry)) { | |
1c755af4 | 703 | struct vfsmount *mounted = lookup_mnt(path); |
463ffb2e AV |
704 | if (!mounted) |
705 | break; | |
706 | dput(path->dentry); | |
707 | if (res) | |
708 | mntput(path->mnt); | |
709 | path->mnt = mounted; | |
710 | path->dentry = dget(mounted->mnt_root); | |
711 | res = 1; | |
712 | } | |
713 | return res; | |
714 | } | |
715 | ||
79ed0226 | 716 | static void follow_mount(struct path *path) |
1da177e4 | 717 | { |
79ed0226 | 718 | while (d_mountpoint(path->dentry)) { |
1c755af4 | 719 | struct vfsmount *mounted = lookup_mnt(path); |
1da177e4 LT |
720 | if (!mounted) |
721 | break; | |
79ed0226 AV |
722 | dput(path->dentry); |
723 | mntput(path->mnt); | |
724 | path->mnt = mounted; | |
725 | path->dentry = dget(mounted->mnt_root); | |
1da177e4 | 726 | } |
1da177e4 LT |
727 | } |
728 | ||
729 | /* no need for dcache_lock, as serialization is taken care in | |
730 | * namespace.c | |
731 | */ | |
9393bd07 | 732 | int follow_down(struct path *path) |
1da177e4 LT |
733 | { |
734 | struct vfsmount *mounted; | |
735 | ||
1c755af4 | 736 | mounted = lookup_mnt(path); |
1da177e4 | 737 | if (mounted) { |
9393bd07 AV |
738 | dput(path->dentry); |
739 | mntput(path->mnt); | |
740 | path->mnt = mounted; | |
741 | path->dentry = dget(mounted->mnt_root); | |
1da177e4 LT |
742 | return 1; |
743 | } | |
744 | return 0; | |
745 | } | |
746 | ||
f1662356 | 747 | static __always_inline void follow_dotdot(struct nameidata *nd) |
1da177e4 | 748 | { |
2a737871 | 749 | set_root(nd); |
e518ddb7 | 750 | |
1da177e4 LT |
751 | while(1) { |
752 | struct vfsmount *parent; | |
4ac91378 | 753 | struct dentry *old = nd->path.dentry; |
1da177e4 | 754 | |
2a737871 AV |
755 | if (nd->path.dentry == nd->root.dentry && |
756 | nd->path.mnt == nd->root.mnt) { | |
1da177e4 LT |
757 | break; |
758 | } | |
1da177e4 | 759 | spin_lock(&dcache_lock); |
4ac91378 JB |
760 | if (nd->path.dentry != nd->path.mnt->mnt_root) { |
761 | nd->path.dentry = dget(nd->path.dentry->d_parent); | |
1da177e4 LT |
762 | spin_unlock(&dcache_lock); |
763 | dput(old); | |
764 | break; | |
765 | } | |
766 | spin_unlock(&dcache_lock); | |
767 | spin_lock(&vfsmount_lock); | |
4ac91378 JB |
768 | parent = nd->path.mnt->mnt_parent; |
769 | if (parent == nd->path.mnt) { | |
1da177e4 LT |
770 | spin_unlock(&vfsmount_lock); |
771 | break; | |
772 | } | |
773 | mntget(parent); | |
4ac91378 | 774 | nd->path.dentry = dget(nd->path.mnt->mnt_mountpoint); |
1da177e4 LT |
775 | spin_unlock(&vfsmount_lock); |
776 | dput(old); | |
4ac91378 JB |
777 | mntput(nd->path.mnt); |
778 | nd->path.mnt = parent; | |
1da177e4 | 779 | } |
79ed0226 | 780 | follow_mount(&nd->path); |
1da177e4 LT |
781 | } |
782 | ||
1da177e4 LT |
783 | /* |
784 | * It's more convoluted than I'd like it to be, but... it's still fairly | |
785 | * small and for now I'd prefer to have fast path as straight as possible. | |
786 | * It _is_ time-critical. | |
787 | */ | |
788 | static int do_lookup(struct nameidata *nd, struct qstr *name, | |
789 | struct path *path) | |
790 | { | |
4ac91378 JB |
791 | struct vfsmount *mnt = nd->path.mnt; |
792 | struct dentry *dentry = __d_lookup(nd->path.dentry, name); | |
1da177e4 LT |
793 | |
794 | if (!dentry) | |
795 | goto need_lookup; | |
796 | if (dentry->d_op && dentry->d_op->d_revalidate) | |
797 | goto need_revalidate; | |
798 | done: | |
799 | path->mnt = mnt; | |
800 | path->dentry = dentry; | |
634ee701 | 801 | __follow_mount(path); |
1da177e4 LT |
802 | return 0; |
803 | ||
804 | need_lookup: | |
4ac91378 | 805 | dentry = real_lookup(nd->path.dentry, name, nd); |
1da177e4 LT |
806 | if (IS_ERR(dentry)) |
807 | goto fail; | |
808 | goto done; | |
809 | ||
810 | need_revalidate: | |
bcdc5e01 IK |
811 | dentry = do_revalidate(dentry, nd); |
812 | if (!dentry) | |
813 | goto need_lookup; | |
814 | if (IS_ERR(dentry)) | |
815 | goto fail; | |
816 | goto done; | |
1da177e4 LT |
817 | |
818 | fail: | |
819 | return PTR_ERR(dentry); | |
820 | } | |
821 | ||
822 | /* | |
823 | * Name resolution. | |
ea3834d9 PM |
824 | * This is the basic name resolution function, turning a pathname into |
825 | * the final dentry. We expect 'base' to be positive and a directory. | |
1da177e4 | 826 | * |
ea3834d9 PM |
827 | * Returns 0 and nd will have valid dentry and mnt on success. |
828 | * Returns error and drops reference to input namei data on failure. | |
1da177e4 | 829 | */ |
fc9b52cd | 830 | static int __link_path_walk(const char *name, struct nameidata *nd) |
1da177e4 LT |
831 | { |
832 | struct path next; | |
833 | struct inode *inode; | |
834 | int err; | |
835 | unsigned int lookup_flags = nd->flags; | |
836 | ||
837 | while (*name=='/') | |
838 | name++; | |
839 | if (!*name) | |
840 | goto return_reval; | |
841 | ||
4ac91378 | 842 | inode = nd->path.dentry->d_inode; |
1da177e4 | 843 | if (nd->depth) |
f55eab82 | 844 | lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE); |
1da177e4 LT |
845 | |
846 | /* At this point we know we have a real path component. */ | |
847 | for(;;) { | |
848 | unsigned long hash; | |
849 | struct qstr this; | |
850 | unsigned int c; | |
851 | ||
cdce5d6b | 852 | nd->flags |= LOOKUP_CONTINUE; |
672b16b2 | 853 | err = exec_permission_lite(inode); |
1da177e4 LT |
854 | if (err) |
855 | break; | |
856 | ||
857 | this.name = name; | |
858 | c = *(const unsigned char *)name; | |
859 | ||
860 | hash = init_name_hash(); | |
861 | do { | |
862 | name++; | |
863 | hash = partial_name_hash(c, hash); | |
864 | c = *(const unsigned char *)name; | |
865 | } while (c && (c != '/')); | |
866 | this.len = name - (const char *) this.name; | |
867 | this.hash = end_name_hash(hash); | |
868 | ||
869 | /* remove trailing slashes? */ | |
870 | if (!c) | |
871 | goto last_component; | |
872 | while (*++name == '/'); | |
873 | if (!*name) | |
874 | goto last_with_slashes; | |
875 | ||
876 | /* | |
877 | * "." and ".." are special - ".." especially so because it has | |
878 | * to be able to know about the current root directory and | |
879 | * parent relationships. | |
880 | */ | |
881 | if (this.name[0] == '.') switch (this.len) { | |
882 | default: | |
883 | break; | |
884 | case 2: | |
885 | if (this.name[1] != '.') | |
886 | break; | |
58c465eb | 887 | follow_dotdot(nd); |
4ac91378 | 888 | inode = nd->path.dentry->d_inode; |
1da177e4 LT |
889 | /* fallthrough */ |
890 | case 1: | |
891 | continue; | |
892 | } | |
893 | /* | |
894 | * See if the low-level filesystem might want | |
895 | * to use its own hash.. | |
896 | */ | |
4ac91378 JB |
897 | if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { |
898 | err = nd->path.dentry->d_op->d_hash(nd->path.dentry, | |
899 | &this); | |
1da177e4 LT |
900 | if (err < 0) |
901 | break; | |
902 | } | |
1da177e4 LT |
903 | /* This does the actual lookups.. */ |
904 | err = do_lookup(nd, &this, &next); | |
905 | if (err) | |
906 | break; | |
1da177e4 LT |
907 | |
908 | err = -ENOENT; | |
909 | inode = next.dentry->d_inode; | |
910 | if (!inode) | |
911 | goto out_dput; | |
1da177e4 LT |
912 | |
913 | if (inode->i_op->follow_link) { | |
90ebe565 | 914 | err = do_follow_link(&next, nd); |
1da177e4 LT |
915 | if (err) |
916 | goto return_err; | |
917 | err = -ENOENT; | |
4ac91378 | 918 | inode = nd->path.dentry->d_inode; |
1da177e4 LT |
919 | if (!inode) |
920 | break; | |
09dd17d3 MS |
921 | } else |
922 | path_to_nameidata(&next, nd); | |
1da177e4 LT |
923 | err = -ENOTDIR; |
924 | if (!inode->i_op->lookup) | |
925 | break; | |
926 | continue; | |
927 | /* here ends the main loop */ | |
928 | ||
929 | last_with_slashes: | |
930 | lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; | |
931 | last_component: | |
f55eab82 TM |
932 | /* Clear LOOKUP_CONTINUE iff it was previously unset */ |
933 | nd->flags &= lookup_flags | ~LOOKUP_CONTINUE; | |
1da177e4 LT |
934 | if (lookup_flags & LOOKUP_PARENT) |
935 | goto lookup_parent; | |
936 | if (this.name[0] == '.') switch (this.len) { | |
937 | default: | |
938 | break; | |
939 | case 2: | |
940 | if (this.name[1] != '.') | |
941 | break; | |
58c465eb | 942 | follow_dotdot(nd); |
4ac91378 | 943 | inode = nd->path.dentry->d_inode; |
1da177e4 LT |
944 | /* fallthrough */ |
945 | case 1: | |
946 | goto return_reval; | |
947 | } | |
4ac91378 JB |
948 | if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { |
949 | err = nd->path.dentry->d_op->d_hash(nd->path.dentry, | |
950 | &this); | |
1da177e4 LT |
951 | if (err < 0) |
952 | break; | |
953 | } | |
954 | err = do_lookup(nd, &this, &next); | |
955 | if (err) | |
956 | break; | |
1da177e4 LT |
957 | inode = next.dentry->d_inode; |
958 | if ((lookup_flags & LOOKUP_FOLLOW) | |
acfa4380 | 959 | && inode && inode->i_op->follow_link) { |
90ebe565 | 960 | err = do_follow_link(&next, nd); |
1da177e4 LT |
961 | if (err) |
962 | goto return_err; | |
4ac91378 | 963 | inode = nd->path.dentry->d_inode; |
09dd17d3 MS |
964 | } else |
965 | path_to_nameidata(&next, nd); | |
1da177e4 LT |
966 | err = -ENOENT; |
967 | if (!inode) | |
968 | break; | |
969 | if (lookup_flags & LOOKUP_DIRECTORY) { | |
970 | err = -ENOTDIR; | |
acfa4380 | 971 | if (!inode->i_op->lookup) |
1da177e4 LT |
972 | break; |
973 | } | |
974 | goto return_base; | |
975 | lookup_parent: | |
976 | nd->last = this; | |
977 | nd->last_type = LAST_NORM; | |
978 | if (this.name[0] != '.') | |
979 | goto return_base; | |
980 | if (this.len == 1) | |
981 | nd->last_type = LAST_DOT; | |
982 | else if (this.len == 2 && this.name[1] == '.') | |
983 | nd->last_type = LAST_DOTDOT; | |
984 | else | |
985 | goto return_base; | |
986 | return_reval: | |
987 | /* | |
988 | * We bypassed the ordinary revalidation routines. | |
989 | * We may need to check the cached dentry for staleness. | |
990 | */ | |
4ac91378 JB |
991 | if (nd->path.dentry && nd->path.dentry->d_sb && |
992 | (nd->path.dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) { | |
1da177e4 LT |
993 | err = -ESTALE; |
994 | /* Note: we do not d_invalidate() */ | |
4ac91378 JB |
995 | if (!nd->path.dentry->d_op->d_revalidate( |
996 | nd->path.dentry, nd)) | |
1da177e4 LT |
997 | break; |
998 | } | |
999 | return_base: | |
1000 | return 0; | |
1001 | out_dput: | |
1d957f9b | 1002 | path_put_conditional(&next, nd); |
1da177e4 LT |
1003 | break; |
1004 | } | |
1d957f9b | 1005 | path_put(&nd->path); |
1da177e4 LT |
1006 | return_err: |
1007 | return err; | |
1008 | } | |
1009 | ||
fc9b52cd | 1010 | static int path_walk(const char *name, struct nameidata *nd) |
1da177e4 LT |
1011 | { |
1012 | current->total_link_count = 0; | |
1013 | return link_path_walk(name, nd); | |
1014 | } | |
1015 | ||
9b4a9b14 | 1016 | static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd) |
1da177e4 | 1017 | { |
ea3834d9 | 1018 | int retval = 0; |
170aa3d0 UD |
1019 | int fput_needed; |
1020 | struct file *file; | |
1da177e4 LT |
1021 | |
1022 | nd->last_type = LAST_ROOT; /* if there are only slashes... */ | |
1023 | nd->flags = flags; | |
1024 | nd->depth = 0; | |
2a737871 | 1025 | nd->root.mnt = NULL; |
1da177e4 | 1026 | |
1da177e4 | 1027 | if (*name=='/') { |
2a737871 AV |
1028 | set_root(nd); |
1029 | nd->path = nd->root; | |
1030 | path_get(&nd->root); | |
5590ff0d | 1031 | } else if (dfd == AT_FDCWD) { |
2a737871 | 1032 | struct fs_struct *fs = current->fs; |
e518ddb7 | 1033 | read_lock(&fs->lock); |
6ac08c39 JB |
1034 | nd->path = fs->pwd; |
1035 | path_get(&fs->pwd); | |
e518ddb7 | 1036 | read_unlock(&fs->lock); |
5590ff0d | 1037 | } else { |
5590ff0d UD |
1038 | struct dentry *dentry; |
1039 | ||
1040 | file = fget_light(dfd, &fput_needed); | |
170aa3d0 UD |
1041 | retval = -EBADF; |
1042 | if (!file) | |
6d09bb62 | 1043 | goto out_fail; |
5590ff0d | 1044 | |
0f7fc9e4 | 1045 | dentry = file->f_path.dentry; |
5590ff0d | 1046 | |
170aa3d0 UD |
1047 | retval = -ENOTDIR; |
1048 | if (!S_ISDIR(dentry->d_inode->i_mode)) | |
6d09bb62 | 1049 | goto fput_fail; |
5590ff0d UD |
1050 | |
1051 | retval = file_permission(file, MAY_EXEC); | |
170aa3d0 | 1052 | if (retval) |
6d09bb62 | 1053 | goto fput_fail; |
5590ff0d | 1054 | |
5dd784d0 JB |
1055 | nd->path = file->f_path; |
1056 | path_get(&file->f_path); | |
5590ff0d UD |
1057 | |
1058 | fput_light(file, fput_needed); | |
1da177e4 | 1059 | } |
9b4a9b14 | 1060 | return 0; |
2dfdd266 | 1061 | |
9b4a9b14 AV |
1062 | fput_fail: |
1063 | fput_light(file, fput_needed); | |
1064 | out_fail: | |
1065 | return retval; | |
1066 | } | |
1067 | ||
1068 | /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ | |
1069 | static int do_path_lookup(int dfd, const char *name, | |
1070 | unsigned int flags, struct nameidata *nd) | |
1071 | { | |
1072 | int retval = path_init(dfd, name, flags, nd); | |
1073 | if (!retval) | |
1074 | retval = path_walk(name, nd); | |
4ac91378 JB |
1075 | if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && |
1076 | nd->path.dentry->d_inode)) | |
1077 | audit_inode(name, nd->path.dentry); | |
2a737871 AV |
1078 | if (nd->root.mnt) { |
1079 | path_put(&nd->root); | |
1080 | nd->root.mnt = NULL; | |
1081 | } | |
170aa3d0 | 1082 | return retval; |
1da177e4 LT |
1083 | } |
1084 | ||
fc9b52cd | 1085 | int path_lookup(const char *name, unsigned int flags, |
5590ff0d UD |
1086 | struct nameidata *nd) |
1087 | { | |
1088 | return do_path_lookup(AT_FDCWD, name, flags, nd); | |
1089 | } | |
1090 | ||
d1811465 AV |
1091 | int kern_path(const char *name, unsigned int flags, struct path *path) |
1092 | { | |
1093 | struct nameidata nd; | |
1094 | int res = do_path_lookup(AT_FDCWD, name, flags, &nd); | |
1095 | if (!res) | |
1096 | *path = nd.path; | |
1097 | return res; | |
1098 | } | |
1099 | ||
16f18200 JJS |
1100 | /** |
1101 | * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair | |
1102 | * @dentry: pointer to dentry of the base directory | |
1103 | * @mnt: pointer to vfs mount of the base directory | |
1104 | * @name: pointer to file name | |
1105 | * @flags: lookup flags | |
1106 | * @nd: pointer to nameidata | |
1107 | */ | |
1108 | int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, | |
1109 | const char *name, unsigned int flags, | |
1110 | struct nameidata *nd) | |
1111 | { | |
1112 | int retval; | |
1113 | ||
1114 | /* same as do_path_lookup */ | |
1115 | nd->last_type = LAST_ROOT; | |
1116 | nd->flags = flags; | |
1117 | nd->depth = 0; | |
1118 | ||
c8e7f449 JB |
1119 | nd->path.dentry = dentry; |
1120 | nd->path.mnt = mnt; | |
1121 | path_get(&nd->path); | |
5b857119 AV |
1122 | nd->root = nd->path; |
1123 | path_get(&nd->root); | |
16f18200 JJS |
1124 | |
1125 | retval = path_walk(name, nd); | |
4ac91378 JB |
1126 | if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && |
1127 | nd->path.dentry->d_inode)) | |
1128 | audit_inode(name, nd->path.dentry); | |
16f18200 | 1129 | |
5b857119 AV |
1130 | path_put(&nd->root); |
1131 | nd->root.mnt = NULL; | |
16f18200 | 1132 | |
2a737871 | 1133 | return retval; |
16f18200 JJS |
1134 | } |
1135 | ||
8737f3a1 AV |
1136 | /** |
1137 | * path_lookup_open - lookup a file path with open intent | |
1138 | * @dfd: the directory to use as base, or AT_FDCWD | |
1139 | * @name: pointer to file name | |
1140 | * @lookup_flags: lookup intent flags | |
1141 | * @nd: pointer to nameidata | |
1142 | * @open_flags: open intent flags | |
1143 | */ | |
6e8341a1 AV |
1144 | static int path_lookup_open(int dfd, const char *name, |
1145 | unsigned int lookup_flags, struct nameidata *nd, int open_flags) | |
834f2a4a TM |
1146 | { |
1147 | struct file *filp = get_empty_filp(); | |
1148 | int err; | |
1149 | ||
1150 | if (filp == NULL) | |
1151 | return -ENFILE; | |
1152 | nd->intent.open.file = filp; | |
1153 | nd->intent.open.flags = open_flags; | |
8737f3a1 | 1154 | nd->intent.open.create_mode = 0; |
5590ff0d | 1155 | err = do_path_lookup(dfd, name, lookup_flags|LOOKUP_OPEN, nd); |
834f2a4a TM |
1156 | if (IS_ERR(nd->intent.open.file)) { |
1157 | if (err == 0) { | |
1158 | err = PTR_ERR(nd->intent.open.file); | |
1d957f9b | 1159 | path_put(&nd->path); |
834f2a4a TM |
1160 | } |
1161 | } else if (err != 0) | |
1162 | release_open_intent(nd); | |
1163 | return err; | |
1164 | } | |
1165 | ||
eead1911 CH |
1166 | static struct dentry *__lookup_hash(struct qstr *name, |
1167 | struct dentry *base, struct nameidata *nd) | |
1da177e4 | 1168 | { |
057f6c01 | 1169 | struct dentry *dentry; |
1da177e4 LT |
1170 | struct inode *inode; |
1171 | int err; | |
1172 | ||
1173 | inode = base->d_inode; | |
1da177e4 LT |
1174 | |
1175 | /* | |
1176 | * See if the low-level filesystem might want | |
1177 | * to use its own hash.. | |
1178 | */ | |
1179 | if (base->d_op && base->d_op->d_hash) { | |
1180 | err = base->d_op->d_hash(base, name); | |
1181 | dentry = ERR_PTR(err); | |
1182 | if (err < 0) | |
1183 | goto out; | |
1184 | } | |
1185 | ||
1186 | dentry = cached_lookup(base, name, nd); | |
1187 | if (!dentry) { | |
d70b67c8 MS |
1188 | struct dentry *new; |
1189 | ||
1190 | /* Don't create child dentry for a dead directory. */ | |
1191 | dentry = ERR_PTR(-ENOENT); | |
1192 | if (IS_DEADDIR(inode)) | |
1193 | goto out; | |
1194 | ||
1195 | new = d_alloc(base, name); | |
1da177e4 LT |
1196 | dentry = ERR_PTR(-ENOMEM); |
1197 | if (!new) | |
1198 | goto out; | |
1199 | dentry = inode->i_op->lookup(inode, new, nd); | |
1200 | if (!dentry) | |
1201 | dentry = new; | |
1202 | else | |
1203 | dput(new); | |
1204 | } | |
1205 | out: | |
1206 | return dentry; | |
1207 | } | |
1208 | ||
057f6c01 JM |
1209 | /* |
1210 | * Restricted form of lookup. Doesn't follow links, single-component only, | |
1211 | * needs parent already locked. Doesn't follow mounts. | |
1212 | * SMP-safe. | |
1213 | */ | |
eead1911 | 1214 | static struct dentry *lookup_hash(struct nameidata *nd) |
057f6c01 | 1215 | { |
057f6c01 JM |
1216 | int err; |
1217 | ||
f419a2e3 | 1218 | err = inode_permission(nd->path.dentry->d_inode, MAY_EXEC); |
057f6c01 | 1219 | if (err) |
eead1911 | 1220 | return ERR_PTR(err); |
4ac91378 | 1221 | return __lookup_hash(&nd->last, nd->path.dentry, nd); |
1da177e4 LT |
1222 | } |
1223 | ||
eead1911 CH |
1224 | static int __lookup_one_len(const char *name, struct qstr *this, |
1225 | struct dentry *base, int len) | |
1da177e4 LT |
1226 | { |
1227 | unsigned long hash; | |
1da177e4 LT |
1228 | unsigned int c; |
1229 | ||
057f6c01 JM |
1230 | this->name = name; |
1231 | this->len = len; | |
1da177e4 | 1232 | if (!len) |
057f6c01 | 1233 | return -EACCES; |
1da177e4 LT |
1234 | |
1235 | hash = init_name_hash(); | |
1236 | while (len--) { | |
1237 | c = *(const unsigned char *)name++; | |
1238 | if (c == '/' || c == '\0') | |
057f6c01 | 1239 | return -EACCES; |
1da177e4 LT |
1240 | hash = partial_name_hash(c, hash); |
1241 | } | |
057f6c01 JM |
1242 | this->hash = end_name_hash(hash); |
1243 | return 0; | |
1244 | } | |
1da177e4 | 1245 | |
eead1911 | 1246 | /** |
a6b91919 | 1247 | * lookup_one_len - filesystem helper to lookup single pathname component |
eead1911 CH |
1248 | * @name: pathname component to lookup |
1249 | * @base: base directory to lookup from | |
1250 | * @len: maximum length @len should be interpreted to | |
1251 | * | |
a6b91919 RD |
1252 | * Note that this routine is purely a helper for filesystem usage and should |
1253 | * not be called by generic code. Also note that by using this function the | |
eead1911 CH |
1254 | * nameidata argument is passed to the filesystem methods and a filesystem |
1255 | * using this helper needs to be prepared for that. | |
1256 | */ | |
057f6c01 JM |
1257 | struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) |
1258 | { | |
1259 | int err; | |
1260 | struct qstr this; | |
1261 | ||
2f9092e1 DW |
1262 | WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); |
1263 | ||
057f6c01 | 1264 | err = __lookup_one_len(name, &this, base, len); |
eead1911 CH |
1265 | if (err) |
1266 | return ERR_PTR(err); | |
1267 | ||
f419a2e3 | 1268 | err = inode_permission(base->d_inode, MAY_EXEC); |
057f6c01 JM |
1269 | if (err) |
1270 | return ERR_PTR(err); | |
49705b77 | 1271 | return __lookup_hash(&this, base, NULL); |
057f6c01 JM |
1272 | } |
1273 | ||
eead1911 CH |
1274 | /** |
1275 | * lookup_one_noperm - bad hack for sysfs | |
1276 | * @name: pathname component to lookup | |
1277 | * @base: base directory to lookup from | |
1278 | * | |
1279 | * This is a variant of lookup_one_len that doesn't perform any permission | |
1280 | * checks. It's a horrible hack to work around the braindead sysfs | |
1281 | * architecture and should not be used anywhere else. | |
1282 | * | |
1283 | * DON'T USE THIS FUNCTION EVER, thanks. | |
1284 | */ | |
1285 | struct dentry *lookup_one_noperm(const char *name, struct dentry *base) | |
057f6c01 JM |
1286 | { |
1287 | int err; | |
1288 | struct qstr this; | |
1289 | ||
eead1911 | 1290 | err = __lookup_one_len(name, &this, base, strlen(name)); |
057f6c01 JM |
1291 | if (err) |
1292 | return ERR_PTR(err); | |
eead1911 | 1293 | return __lookup_hash(&this, base, NULL); |
1da177e4 LT |
1294 | } |
1295 | ||
2d8f3038 AV |
1296 | int user_path_at(int dfd, const char __user *name, unsigned flags, |
1297 | struct path *path) | |
1da177e4 | 1298 | { |
2d8f3038 | 1299 | struct nameidata nd; |
1da177e4 LT |
1300 | char *tmp = getname(name); |
1301 | int err = PTR_ERR(tmp); | |
1da177e4 | 1302 | if (!IS_ERR(tmp)) { |
2d8f3038 AV |
1303 | |
1304 | BUG_ON(flags & LOOKUP_PARENT); | |
1305 | ||
1306 | err = do_path_lookup(dfd, tmp, flags, &nd); | |
1da177e4 | 1307 | putname(tmp); |
2d8f3038 AV |
1308 | if (!err) |
1309 | *path = nd.path; | |
1da177e4 LT |
1310 | } |
1311 | return err; | |
1312 | } | |
1313 | ||
2ad94ae6 AV |
1314 | static int user_path_parent(int dfd, const char __user *path, |
1315 | struct nameidata *nd, char **name) | |
1316 | { | |
1317 | char *s = getname(path); | |
1318 | int error; | |
1319 | ||
1320 | if (IS_ERR(s)) | |
1321 | return PTR_ERR(s); | |
1322 | ||
1323 | error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd); | |
1324 | if (error) | |
1325 | putname(s); | |
1326 | else | |
1327 | *name = s; | |
1328 | ||
1329 | return error; | |
1330 | } | |
1331 | ||
1da177e4 LT |
1332 | /* |
1333 | * It's inline, so penalty for filesystems that don't use sticky bit is | |
1334 | * minimal. | |
1335 | */ | |
1336 | static inline int check_sticky(struct inode *dir, struct inode *inode) | |
1337 | { | |
da9592ed DH |
1338 | uid_t fsuid = current_fsuid(); |
1339 | ||
1da177e4 LT |
1340 | if (!(dir->i_mode & S_ISVTX)) |
1341 | return 0; | |
da9592ed | 1342 | if (inode->i_uid == fsuid) |
1da177e4 | 1343 | return 0; |
da9592ed | 1344 | if (dir->i_uid == fsuid) |
1da177e4 LT |
1345 | return 0; |
1346 | return !capable(CAP_FOWNER); | |
1347 | } | |
1348 | ||
1349 | /* | |
1350 | * Check whether we can remove a link victim from directory dir, check | |
1351 | * whether the type of victim is right. | |
1352 | * 1. We can't do it if dir is read-only (done in permission()) | |
1353 | * 2. We should have write and exec permissions on dir | |
1354 | * 3. We can't remove anything from append-only dir | |
1355 | * 4. We can't do anything with immutable dir (done in permission()) | |
1356 | * 5. If the sticky bit on dir is set we should either | |
1357 | * a. be owner of dir, or | |
1358 | * b. be owner of victim, or | |
1359 | * c. have CAP_FOWNER capability | |
1360 | * 6. If the victim is append-only or immutable we can't do antyhing with | |
1361 | * links pointing to it. | |
1362 | * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. | |
1363 | * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. | |
1364 | * 9. We can't remove a root or mountpoint. | |
1365 | * 10. We don't allow removal of NFS sillyrenamed files; it's handled by | |
1366 | * nfs_async_unlink(). | |
1367 | */ | |
858119e1 | 1368 | static int may_delete(struct inode *dir,struct dentry *victim,int isdir) |
1da177e4 LT |
1369 | { |
1370 | int error; | |
1371 | ||
1372 | if (!victim->d_inode) | |
1373 | return -ENOENT; | |
1374 | ||
1375 | BUG_ON(victim->d_parent->d_inode != dir); | |
5a190ae6 | 1376 | audit_inode_child(victim->d_name.name, victim, dir); |
1da177e4 | 1377 | |
f419a2e3 | 1378 | error = inode_permission(dir, MAY_WRITE | MAY_EXEC); |
1da177e4 LT |
1379 | if (error) |
1380 | return error; | |
1381 | if (IS_APPEND(dir)) | |
1382 | return -EPERM; | |
1383 | if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| | |
f9454548 | 1384 | IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) |
1da177e4 LT |
1385 | return -EPERM; |
1386 | if (isdir) { | |
1387 | if (!S_ISDIR(victim->d_inode->i_mode)) | |
1388 | return -ENOTDIR; | |
1389 | if (IS_ROOT(victim)) | |
1390 | return -EBUSY; | |
1391 | } else if (S_ISDIR(victim->d_inode->i_mode)) | |
1392 | return -EISDIR; | |
1393 | if (IS_DEADDIR(dir)) | |
1394 | return -ENOENT; | |
1395 | if (victim->d_flags & DCACHE_NFSFS_RENAMED) | |
1396 | return -EBUSY; | |
1397 | return 0; | |
1398 | } | |
1399 | ||
1400 | /* Check whether we can create an object with dentry child in directory | |
1401 | * dir. | |
1402 | * 1. We can't do it if child already exists (open has special treatment for | |
1403 | * this case, but since we are inlined it's OK) | |
1404 | * 2. We can't do it if dir is read-only (done in permission()) | |
1405 | * 3. We should have write and exec permissions on dir | |
1406 | * 4. We can't do it if dir is immutable (done in permission()) | |
1407 | */ | |
a95164d9 | 1408 | static inline int may_create(struct inode *dir, struct dentry *child) |
1da177e4 LT |
1409 | { |
1410 | if (child->d_inode) | |
1411 | return -EEXIST; | |
1412 | if (IS_DEADDIR(dir)) | |
1413 | return -ENOENT; | |
f419a2e3 | 1414 | return inode_permission(dir, MAY_WRITE | MAY_EXEC); |
1da177e4 LT |
1415 | } |
1416 | ||
1417 | /* | |
1da177e4 LT |
1418 | * O_DIRECTORY translates into forcing a directory lookup. |
1419 | */ | |
1420 | static inline int lookup_flags(unsigned int f) | |
1421 | { | |
1422 | unsigned long retval = LOOKUP_FOLLOW; | |
1423 | ||
1424 | if (f & O_NOFOLLOW) | |
1425 | retval &= ~LOOKUP_FOLLOW; | |
1426 | ||
1da177e4 LT |
1427 | if (f & O_DIRECTORY) |
1428 | retval |= LOOKUP_DIRECTORY; | |
1429 | ||
1430 | return retval; | |
1431 | } | |
1432 | ||
1433 | /* | |
1434 | * p1 and p2 should be directories on the same fs. | |
1435 | */ | |
1436 | struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) | |
1437 | { | |
1438 | struct dentry *p; | |
1439 | ||
1440 | if (p1 == p2) { | |
f2eace23 | 1441 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
1da177e4 LT |
1442 | return NULL; |
1443 | } | |
1444 | ||
a11f3a05 | 1445 | mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
1da177e4 | 1446 | |
e2761a11 OH |
1447 | p = d_ancestor(p2, p1); |
1448 | if (p) { | |
1449 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); | |
1450 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); | |
1451 | return p; | |
1da177e4 LT |
1452 | } |
1453 | ||
e2761a11 OH |
1454 | p = d_ancestor(p1, p2); |
1455 | if (p) { | |
1456 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); | |
1457 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); | |
1458 | return p; | |
1da177e4 LT |
1459 | } |
1460 | ||
f2eace23 IM |
1461 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
1462 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); | |
1da177e4 LT |
1463 | return NULL; |
1464 | } | |
1465 | ||
1466 | void unlock_rename(struct dentry *p1, struct dentry *p2) | |
1467 | { | |
1b1dcc1b | 1468 | mutex_unlock(&p1->d_inode->i_mutex); |
1da177e4 | 1469 | if (p1 != p2) { |
1b1dcc1b | 1470 | mutex_unlock(&p2->d_inode->i_mutex); |
a11f3a05 | 1471 | mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
1da177e4 LT |
1472 | } |
1473 | } | |
1474 | ||
1475 | int vfs_create(struct inode *dir, struct dentry *dentry, int mode, | |
1476 | struct nameidata *nd) | |
1477 | { | |
a95164d9 | 1478 | int error = may_create(dir, dentry); |
1da177e4 LT |
1479 | |
1480 | if (error) | |
1481 | return error; | |
1482 | ||
acfa4380 | 1483 | if (!dir->i_op->create) |
1da177e4 LT |
1484 | return -EACCES; /* shouldn't it be ENOSYS? */ |
1485 | mode &= S_IALLUGO; | |
1486 | mode |= S_IFREG; | |
1487 | error = security_inode_create(dir, dentry, mode); | |
1488 | if (error) | |
1489 | return error; | |
9e3509e2 | 1490 | vfs_dq_init(dir); |
1da177e4 | 1491 | error = dir->i_op->create(dir, dentry, mode, nd); |
a74574aa | 1492 | if (!error) |
f38aa942 | 1493 | fsnotify_create(dir, dentry); |
1da177e4 LT |
1494 | return error; |
1495 | } | |
1496 | ||
3fb64190 | 1497 | int may_open(struct path *path, int acc_mode, int flag) |
1da177e4 | 1498 | { |
3fb64190 | 1499 | struct dentry *dentry = path->dentry; |
1da177e4 LT |
1500 | struct inode *inode = dentry->d_inode; |
1501 | int error; | |
1502 | ||
1503 | if (!inode) | |
1504 | return -ENOENT; | |
1505 | ||
c8fe8f30 CH |
1506 | switch (inode->i_mode & S_IFMT) { |
1507 | case S_IFLNK: | |
1da177e4 | 1508 | return -ELOOP; |
c8fe8f30 CH |
1509 | case S_IFDIR: |
1510 | if (acc_mode & MAY_WRITE) | |
1511 | return -EISDIR; | |
1512 | break; | |
1513 | case S_IFBLK: | |
1514 | case S_IFCHR: | |
3fb64190 | 1515 | if (path->mnt->mnt_flags & MNT_NODEV) |
1da177e4 | 1516 | return -EACCES; |
c8fe8f30 CH |
1517 | /*FALLTHRU*/ |
1518 | case S_IFIFO: | |
1519 | case S_IFSOCK: | |
1da177e4 | 1520 | flag &= ~O_TRUNC; |
c8fe8f30 | 1521 | break; |
4a3fd211 | 1522 | } |
b41572e9 | 1523 | |
3fb64190 | 1524 | error = inode_permission(inode, acc_mode); |
b41572e9 DH |
1525 | if (error) |
1526 | return error; | |
6146f0d5 | 1527 | |
cb5629b1 | 1528 | error = ima_path_check(path, |
b9fc745d MZ |
1529 | acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC), |
1530 | IMA_COUNT_UPDATE); | |
6146f0d5 MZ |
1531 | if (error) |
1532 | return error; | |
1da177e4 LT |
1533 | /* |
1534 | * An append-only file must be opened in append mode for writing. | |
1535 | */ | |
1536 | if (IS_APPEND(inode)) { | |
acd0c935 | 1537 | error = -EPERM; |
1da177e4 | 1538 | if ((flag & FMODE_WRITE) && !(flag & O_APPEND)) |
acd0c935 | 1539 | goto err_out; |
1da177e4 | 1540 | if (flag & O_TRUNC) |
acd0c935 | 1541 | goto err_out; |
1da177e4 LT |
1542 | } |
1543 | ||
1544 | /* O_NOATIME can only be set by the owner or superuser */ | |
1545 | if (flag & O_NOATIME) | |
acd0c935 MZ |
1546 | if (!is_owner_or_cap(inode)) { |
1547 | error = -EPERM; | |
1548 | goto err_out; | |
1549 | } | |
1da177e4 LT |
1550 | |
1551 | /* | |
1552 | * Ensure there are no outstanding leases on the file. | |
1553 | */ | |
1554 | error = break_lease(inode, flag); | |
1555 | if (error) | |
acd0c935 | 1556 | goto err_out; |
1da177e4 LT |
1557 | |
1558 | if (flag & O_TRUNC) { | |
1559 | error = get_write_access(inode); | |
1560 | if (error) | |
acd0c935 | 1561 | goto err_out; |
1da177e4 LT |
1562 | |
1563 | /* | |
1564 | * Refuse to truncate files with mandatory locks held on them. | |
1565 | */ | |
1566 | error = locks_verify_locked(inode); | |
be6d3e56 | 1567 | if (!error) |
3fb64190 | 1568 | error = security_path_truncate(path, 0, |
be6d3e56 | 1569 | ATTR_MTIME|ATTR_CTIME|ATTR_OPEN); |
1da177e4 | 1570 | if (!error) { |
9e3509e2 | 1571 | vfs_dq_init(inode); |
d139d7ff MS |
1572 | |
1573 | error = do_truncate(dentry, 0, | |
1574 | ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, | |
1575 | NULL); | |
1da177e4 LT |
1576 | } |
1577 | put_write_access(inode); | |
1578 | if (error) | |
acd0c935 | 1579 | goto err_out; |
1da177e4 LT |
1580 | } else |
1581 | if (flag & FMODE_WRITE) | |
9e3509e2 | 1582 | vfs_dq_init(inode); |
1da177e4 LT |
1583 | |
1584 | return 0; | |
acd0c935 MZ |
1585 | err_out: |
1586 | ima_counts_put(path, acc_mode ? | |
1587 | acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC) : | |
1588 | ACC_MODE(flag) & (MAY_READ | MAY_WRITE)); | |
1589 | return error; | |
1da177e4 LT |
1590 | } |
1591 | ||
d57999e1 DH |
1592 | /* |
1593 | * Be careful about ever adding any more callers of this | |
1594 | * function. Its flags must be in the namei format, not | |
1595 | * what get passed to sys_open(). | |
1596 | */ | |
1597 | static int __open_namei_create(struct nameidata *nd, struct path *path, | |
aab520e2 DH |
1598 | int flag, int mode) |
1599 | { | |
1600 | int error; | |
4ac91378 | 1601 | struct dentry *dir = nd->path.dentry; |
aab520e2 DH |
1602 | |
1603 | if (!IS_POSIXACL(dir->d_inode)) | |
ce3b0f8d | 1604 | mode &= ~current_umask(); |
be6d3e56 KT |
1605 | error = security_path_mknod(&nd->path, path->dentry, mode, 0); |
1606 | if (error) | |
1607 | goto out_unlock; | |
aab520e2 | 1608 | error = vfs_create(dir->d_inode, path->dentry, mode, nd); |
be6d3e56 | 1609 | out_unlock: |
aab520e2 | 1610 | mutex_unlock(&dir->d_inode->i_mutex); |
4ac91378 JB |
1611 | dput(nd->path.dentry); |
1612 | nd->path.dentry = path->dentry; | |
aab520e2 DH |
1613 | if (error) |
1614 | return error; | |
1615 | /* Don't check for write permission, don't truncate */ | |
3fb64190 | 1616 | return may_open(&nd->path, 0, flag & ~O_TRUNC); |
aab520e2 DH |
1617 | } |
1618 | ||
d57999e1 DH |
1619 | /* |
1620 | * Note that while the flag value (low two bits) for sys_open means: | |
1621 | * 00 - read-only | |
1622 | * 01 - write-only | |
1623 | * 10 - read-write | |
1624 | * 11 - special | |
1625 | * it is changed into | |
1626 | * 00 - no permissions needed | |
1627 | * 01 - read-permission | |
1628 | * 10 - write-permission | |
1629 | * 11 - read-write | |
1630 | * for the internal routines (ie open_namei()/follow_link() etc) | |
1631 | * This is more logical, and also allows the 00 "no perm needed" | |
1632 | * to be used for symlinks (where the permissions are checked | |
1633 | * later). | |
1634 | * | |
1635 | */ | |
1636 | static inline int open_to_namei_flags(int flag) | |
1637 | { | |
1638 | if ((flag+1) & O_ACCMODE) | |
1639 | flag++; | |
1640 | return flag; | |
1641 | } | |
1642 | ||
4a3fd211 DH |
1643 | static int open_will_write_to_fs(int flag, struct inode *inode) |
1644 | { | |
1645 | /* | |
1646 | * We'll never write to the fs underlying | |
1647 | * a device file. | |
1648 | */ | |
1649 | if (special_file(inode->i_mode)) | |
1650 | return 0; | |
1651 | return (flag & O_TRUNC); | |
1652 | } | |
1653 | ||
1da177e4 | 1654 | /* |
4a3fd211 DH |
1655 | * Note that the low bits of the passed in "open_flag" |
1656 | * are not the same as in the local variable "flag". See | |
1657 | * open_to_namei_flags() for more details. | |
1da177e4 | 1658 | */ |
a70e65df | 1659 | struct file *do_filp_open(int dfd, const char *pathname, |
6e8341a1 | 1660 | int open_flag, int mode, int acc_mode) |
1da177e4 | 1661 | { |
4a3fd211 | 1662 | struct file *filp; |
a70e65df | 1663 | struct nameidata nd; |
6e8341a1 | 1664 | int error; |
4e7506e4 | 1665 | struct path path; |
1da177e4 LT |
1666 | struct dentry *dir; |
1667 | int count = 0; | |
4a3fd211 | 1668 | int will_write; |
d57999e1 | 1669 | int flag = open_to_namei_flags(open_flag); |
1da177e4 | 1670 | |
6e8341a1 AV |
1671 | if (!acc_mode) |
1672 | acc_mode = MAY_OPEN | ACC_MODE(flag); | |
1da177e4 | 1673 | |
834f2a4a TM |
1674 | /* O_TRUNC implies we need access checks for write permissions */ |
1675 | if (flag & O_TRUNC) | |
1676 | acc_mode |= MAY_WRITE; | |
1677 | ||
1da177e4 LT |
1678 | /* Allow the LSM permission hook to distinguish append |
1679 | access from general write access. */ | |
1680 | if (flag & O_APPEND) | |
1681 | acc_mode |= MAY_APPEND; | |
1682 | ||
1da177e4 LT |
1683 | /* |
1684 | * The simplest case - just a plain lookup. | |
1685 | */ | |
1686 | if (!(flag & O_CREAT)) { | |
5590ff0d | 1687 | error = path_lookup_open(dfd, pathname, lookup_flags(flag), |
a70e65df | 1688 | &nd, flag); |
1da177e4 | 1689 | if (error) |
a70e65df | 1690 | return ERR_PTR(error); |
1da177e4 LT |
1691 | goto ok; |
1692 | } | |
1693 | ||
1694 | /* | |
1695 | * Create - we need to know the parent. | |
1696 | */ | |
9b4a9b14 | 1697 | error = path_init(dfd, pathname, LOOKUP_PARENT, &nd); |
1da177e4 | 1698 | if (error) |
a70e65df | 1699 | return ERR_PTR(error); |
9b4a9b14 | 1700 | error = path_walk(pathname, &nd); |
654f562c O |
1701 | if (error) { |
1702 | if (nd.root.mnt) | |
1703 | path_put(&nd.root); | |
9b4a9b14 | 1704 | return ERR_PTR(error); |
654f562c | 1705 | } |
9b4a9b14 AV |
1706 | if (unlikely(!audit_dummy_context())) |
1707 | audit_inode(pathname, nd.path.dentry); | |
1da177e4 LT |
1708 | |
1709 | /* | |
1710 | * We have the parent and last component. First of all, check | |
1711 | * that we are not asked to creat(2) an obvious directory - that | |
1712 | * will not do. | |
1713 | */ | |
1714 | error = -EISDIR; | |
a70e65df | 1715 | if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len]) |
8737f3a1 | 1716 | goto exit_parent; |
1da177e4 | 1717 | |
8737f3a1 AV |
1718 | error = -ENFILE; |
1719 | filp = get_empty_filp(); | |
1720 | if (filp == NULL) | |
1721 | goto exit_parent; | |
1722 | nd.intent.open.file = filp; | |
1723 | nd.intent.open.flags = flag; | |
1724 | nd.intent.open.create_mode = mode; | |
a70e65df CH |
1725 | dir = nd.path.dentry; |
1726 | nd.flags &= ~LOOKUP_PARENT; | |
8737f3a1 | 1727 | nd.flags |= LOOKUP_CREATE | LOOKUP_OPEN; |
3516586a AV |
1728 | if (flag & O_EXCL) |
1729 | nd.flags |= LOOKUP_EXCL; | |
1b1dcc1b | 1730 | mutex_lock(&dir->d_inode->i_mutex); |
a70e65df CH |
1731 | path.dentry = lookup_hash(&nd); |
1732 | path.mnt = nd.path.mnt; | |
1da177e4 LT |
1733 | |
1734 | do_last: | |
4e7506e4 AV |
1735 | error = PTR_ERR(path.dentry); |
1736 | if (IS_ERR(path.dentry)) { | |
1b1dcc1b | 1737 | mutex_unlock(&dir->d_inode->i_mutex); |
1da177e4 LT |
1738 | goto exit; |
1739 | } | |
1740 | ||
a70e65df | 1741 | if (IS_ERR(nd.intent.open.file)) { |
a70e65df | 1742 | error = PTR_ERR(nd.intent.open.file); |
4a3fd211 | 1743 | goto exit_mutex_unlock; |
4af4c52f OD |
1744 | } |
1745 | ||
1da177e4 | 1746 | /* Negative dentry, just create the file */ |
4e7506e4 | 1747 | if (!path.dentry->d_inode) { |
4a3fd211 DH |
1748 | /* |
1749 | * This write is needed to ensure that a | |
1750 | * ro->rw transition does not occur between | |
1751 | * the time when the file is created and when | |
1752 | * a permanent write count is taken through | |
1753 | * the 'struct file' in nameidata_to_filp(). | |
1754 | */ | |
1755 | error = mnt_want_write(nd.path.mnt); | |
1da177e4 | 1756 | if (error) |
4a3fd211 DH |
1757 | goto exit_mutex_unlock; |
1758 | error = __open_namei_create(&nd, &path, flag, mode); | |
1759 | if (error) { | |
1760 | mnt_drop_write(nd.path.mnt); | |
1da177e4 | 1761 | goto exit; |
4a3fd211 DH |
1762 | } |
1763 | filp = nameidata_to_filp(&nd, open_flag); | |
94e5d714 MZ |
1764 | if (IS_ERR(filp)) |
1765 | ima_counts_put(&nd.path, | |
1766 | acc_mode & (MAY_READ | MAY_WRITE | | |
1767 | MAY_EXEC)); | |
4a3fd211 | 1768 | mnt_drop_write(nd.path.mnt); |
654f562c O |
1769 | if (nd.root.mnt) |
1770 | path_put(&nd.root); | |
4a3fd211 | 1771 | return filp; |
1da177e4 LT |
1772 | } |
1773 | ||
1774 | /* | |
1775 | * It already exists. | |
1776 | */ | |
1b1dcc1b | 1777 | mutex_unlock(&dir->d_inode->i_mutex); |
5a190ae6 | 1778 | audit_inode(pathname, path.dentry); |
1da177e4 LT |
1779 | |
1780 | error = -EEXIST; | |
1781 | if (flag & O_EXCL) | |
1782 | goto exit_dput; | |
1783 | ||
e13b210f | 1784 | if (__follow_mount(&path)) { |
1da177e4 | 1785 | error = -ELOOP; |
ba7a4c1a AV |
1786 | if (flag & O_NOFOLLOW) |
1787 | goto exit_dput; | |
1da177e4 | 1788 | } |
3e2efce0 | 1789 | |
1da177e4 | 1790 | error = -ENOENT; |
4e7506e4 | 1791 | if (!path.dentry->d_inode) |
1da177e4 | 1792 | goto exit_dput; |
acfa4380 | 1793 | if (path.dentry->d_inode->i_op->follow_link) |
1da177e4 LT |
1794 | goto do_link; |
1795 | ||
a70e65df | 1796 | path_to_nameidata(&path, &nd); |
1da177e4 | 1797 | error = -EISDIR; |
4e7506e4 | 1798 | if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode)) |
1da177e4 LT |
1799 | goto exit; |
1800 | ok: | |
4a3fd211 DH |
1801 | /* |
1802 | * Consider: | |
1803 | * 1. may_open() truncates a file | |
1804 | * 2. a rw->ro mount transition occurs | |
1805 | * 3. nameidata_to_filp() fails due to | |
1806 | * the ro mount. | |
1807 | * That would be inconsistent, and should | |
1808 | * be avoided. Taking this mnt write here | |
1809 | * ensures that (2) can not occur. | |
1810 | */ | |
1811 | will_write = open_will_write_to_fs(flag, nd.path.dentry->d_inode); | |
1812 | if (will_write) { | |
1813 | error = mnt_want_write(nd.path.mnt); | |
1814 | if (error) | |
1815 | goto exit; | |
1816 | } | |
3fb64190 | 1817 | error = may_open(&nd.path, acc_mode, flag); |
4a3fd211 DH |
1818 | if (error) { |
1819 | if (will_write) | |
1820 | mnt_drop_write(nd.path.mnt); | |
1da177e4 | 1821 | goto exit; |
4a3fd211 DH |
1822 | } |
1823 | filp = nameidata_to_filp(&nd, open_flag); | |
94e5d714 MZ |
1824 | if (IS_ERR(filp)) |
1825 | ima_counts_put(&nd.path, | |
1826 | acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC)); | |
4a3fd211 DH |
1827 | /* |
1828 | * It is now safe to drop the mnt write | |
1829 | * because the filp has had a write taken | |
1830 | * on its behalf. | |
1831 | */ | |
1832 | if (will_write) | |
1833 | mnt_drop_write(nd.path.mnt); | |
654f562c O |
1834 | if (nd.root.mnt) |
1835 | path_put(&nd.root); | |
4a3fd211 | 1836 | return filp; |
1da177e4 | 1837 | |
4a3fd211 DH |
1838 | exit_mutex_unlock: |
1839 | mutex_unlock(&dir->d_inode->i_mutex); | |
1da177e4 | 1840 | exit_dput: |
a70e65df | 1841 | path_put_conditional(&path, &nd); |
1da177e4 | 1842 | exit: |
a70e65df CH |
1843 | if (!IS_ERR(nd.intent.open.file)) |
1844 | release_open_intent(&nd); | |
8737f3a1 | 1845 | exit_parent: |
2a737871 AV |
1846 | if (nd.root.mnt) |
1847 | path_put(&nd.root); | |
a70e65df CH |
1848 | path_put(&nd.path); |
1849 | return ERR_PTR(error); | |
1da177e4 LT |
1850 | |
1851 | do_link: | |
1852 | error = -ELOOP; | |
1853 | if (flag & O_NOFOLLOW) | |
1854 | goto exit_dput; | |
1855 | /* | |
1856 | * This is subtle. Instead of calling do_follow_link() we do the | |
1857 | * thing by hands. The reason is that this way we have zero link_count | |
1858 | * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT. | |
1859 | * After that we have the parent and last component, i.e. | |
1860 | * we are in the same situation as after the first path_walk(). | |
1861 | * Well, almost - if the last component is normal we get its copy | |
1862 | * stored in nd->last.name and we will have to putname() it when we | |
1863 | * are done. Procfs-like symlinks just set LAST_BIND. | |
1864 | */ | |
a70e65df CH |
1865 | nd.flags |= LOOKUP_PARENT; |
1866 | error = security_inode_follow_link(path.dentry, &nd); | |
1da177e4 LT |
1867 | if (error) |
1868 | goto exit_dput; | |
a70e65df | 1869 | error = __do_follow_link(&path, &nd); |
de459215 KK |
1870 | if (error) { |
1871 | /* Does someone understand code flow here? Or it is only | |
1872 | * me so stupid? Anathema to whoever designed this non-sense | |
1873 | * with "intent.open". | |
1874 | */ | |
a70e65df | 1875 | release_open_intent(&nd); |
654f562c O |
1876 | if (nd.root.mnt) |
1877 | path_put(&nd.root); | |
a70e65df | 1878 | return ERR_PTR(error); |
de459215 | 1879 | } |
a70e65df CH |
1880 | nd.flags &= ~LOOKUP_PARENT; |
1881 | if (nd.last_type == LAST_BIND) | |
1da177e4 | 1882 | goto ok; |
1da177e4 | 1883 | error = -EISDIR; |
a70e65df | 1884 | if (nd.last_type != LAST_NORM) |
1da177e4 | 1885 | goto exit; |
a70e65df CH |
1886 | if (nd.last.name[nd.last.len]) { |
1887 | __putname(nd.last.name); | |
1da177e4 LT |
1888 | goto exit; |
1889 | } | |
1890 | error = -ELOOP; | |
1891 | if (count++==32) { | |
a70e65df | 1892 | __putname(nd.last.name); |
1da177e4 LT |
1893 | goto exit; |
1894 | } | |
a70e65df | 1895 | dir = nd.path.dentry; |
1b1dcc1b | 1896 | mutex_lock(&dir->d_inode->i_mutex); |
a70e65df CH |
1897 | path.dentry = lookup_hash(&nd); |
1898 | path.mnt = nd.path.mnt; | |
1899 | __putname(nd.last.name); | |
1da177e4 LT |
1900 | goto do_last; |
1901 | } | |
1902 | ||
a70e65df CH |
1903 | /** |
1904 | * filp_open - open file and return file pointer | |
1905 | * | |
1906 | * @filename: path to open | |
1907 | * @flags: open flags as per the open(2) second argument | |
1908 | * @mode: mode for the new file if O_CREAT is set, else ignored | |
1909 | * | |
1910 | * This is the helper to open a file from kernelspace if you really | |
1911 | * have to. But in generally you should not do this, so please move | |
1912 | * along, nothing to see here.. | |
1913 | */ | |
1914 | struct file *filp_open(const char *filename, int flags, int mode) | |
1915 | { | |
6e8341a1 | 1916 | return do_filp_open(AT_FDCWD, filename, flags, mode, 0); |
a70e65df CH |
1917 | } |
1918 | EXPORT_SYMBOL(filp_open); | |
1919 | ||
1da177e4 LT |
1920 | /** |
1921 | * lookup_create - lookup a dentry, creating it if it doesn't exist | |
1922 | * @nd: nameidata info | |
1923 | * @is_dir: directory flag | |
1924 | * | |
1925 | * Simple function to lookup and return a dentry and create it | |
1926 | * if it doesn't exist. Is SMP-safe. | |
c663e5d8 | 1927 | * |
4ac91378 | 1928 | * Returns with nd->path.dentry->d_inode->i_mutex locked. |
1da177e4 LT |
1929 | */ |
1930 | struct dentry *lookup_create(struct nameidata *nd, int is_dir) | |
1931 | { | |
c663e5d8 | 1932 | struct dentry *dentry = ERR_PTR(-EEXIST); |
1da177e4 | 1933 | |
4ac91378 | 1934 | mutex_lock_nested(&nd->path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
c663e5d8 CH |
1935 | /* |
1936 | * Yucky last component or no last component at all? | |
1937 | * (foo/., foo/.., /////) | |
1938 | */ | |
1da177e4 LT |
1939 | if (nd->last_type != LAST_NORM) |
1940 | goto fail; | |
1941 | nd->flags &= ~LOOKUP_PARENT; | |
3516586a | 1942 | nd->flags |= LOOKUP_CREATE | LOOKUP_EXCL; |
a634904a | 1943 | nd->intent.open.flags = O_EXCL; |
c663e5d8 CH |
1944 | |
1945 | /* | |
1946 | * Do the final lookup. | |
1947 | */ | |
49705b77 | 1948 | dentry = lookup_hash(nd); |
1da177e4 LT |
1949 | if (IS_ERR(dentry)) |
1950 | goto fail; | |
c663e5d8 | 1951 | |
e9baf6e5 AV |
1952 | if (dentry->d_inode) |
1953 | goto eexist; | |
c663e5d8 CH |
1954 | /* |
1955 | * Special case - lookup gave negative, but... we had foo/bar/ | |
1956 | * From the vfs_mknod() POV we just have a negative dentry - | |
1957 | * all is fine. Let's be bastards - you had / on the end, you've | |
1958 | * been asking for (non-existent) directory. -ENOENT for you. | |
1959 | */ | |
e9baf6e5 AV |
1960 | if (unlikely(!is_dir && nd->last.name[nd->last.len])) { |
1961 | dput(dentry); | |
1962 | dentry = ERR_PTR(-ENOENT); | |
1963 | } | |
1da177e4 | 1964 | return dentry; |
e9baf6e5 | 1965 | eexist: |
1da177e4 | 1966 | dput(dentry); |
e9baf6e5 | 1967 | dentry = ERR_PTR(-EEXIST); |
1da177e4 LT |
1968 | fail: |
1969 | return dentry; | |
1970 | } | |
f81a0bff | 1971 | EXPORT_SYMBOL_GPL(lookup_create); |
1da177e4 LT |
1972 | |
1973 | int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1974 | { | |
a95164d9 | 1975 | int error = may_create(dir, dentry); |
1da177e4 LT |
1976 | |
1977 | if (error) | |
1978 | return error; | |
1979 | ||
1980 | if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) | |
1981 | return -EPERM; | |
1982 | ||
acfa4380 | 1983 | if (!dir->i_op->mknod) |
1da177e4 LT |
1984 | return -EPERM; |
1985 | ||
08ce5f16 SH |
1986 | error = devcgroup_inode_mknod(mode, dev); |
1987 | if (error) | |
1988 | return error; | |
1989 | ||
1da177e4 LT |
1990 | error = security_inode_mknod(dir, dentry, mode, dev); |
1991 | if (error) | |
1992 | return error; | |
1993 | ||
9e3509e2 | 1994 | vfs_dq_init(dir); |
1da177e4 | 1995 | error = dir->i_op->mknod(dir, dentry, mode, dev); |
a74574aa | 1996 | if (!error) |
f38aa942 | 1997 | fsnotify_create(dir, dentry); |
1da177e4 LT |
1998 | return error; |
1999 | } | |
2000 | ||
463c3197 DH |
2001 | static int may_mknod(mode_t mode) |
2002 | { | |
2003 | switch (mode & S_IFMT) { | |
2004 | case S_IFREG: | |
2005 | case S_IFCHR: | |
2006 | case S_IFBLK: | |
2007 | case S_IFIFO: | |
2008 | case S_IFSOCK: | |
2009 | case 0: /* zero mode translates to S_IFREG */ | |
2010 | return 0; | |
2011 | case S_IFDIR: | |
2012 | return -EPERM; | |
2013 | default: | |
2014 | return -EINVAL; | |
2015 | } | |
2016 | } | |
2017 | ||
2e4d0924 HC |
2018 | SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, int, mode, |
2019 | unsigned, dev) | |
1da177e4 | 2020 | { |
2ad94ae6 AV |
2021 | int error; |
2022 | char *tmp; | |
2023 | struct dentry *dentry; | |
1da177e4 LT |
2024 | struct nameidata nd; |
2025 | ||
2026 | if (S_ISDIR(mode)) | |
2027 | return -EPERM; | |
1da177e4 | 2028 | |
2ad94ae6 | 2029 | error = user_path_parent(dfd, filename, &nd, &tmp); |
1da177e4 | 2030 | if (error) |
2ad94ae6 AV |
2031 | return error; |
2032 | ||
1da177e4 | 2033 | dentry = lookup_create(&nd, 0); |
463c3197 DH |
2034 | if (IS_ERR(dentry)) { |
2035 | error = PTR_ERR(dentry); | |
2036 | goto out_unlock; | |
2037 | } | |
4ac91378 | 2038 | if (!IS_POSIXACL(nd.path.dentry->d_inode)) |
ce3b0f8d | 2039 | mode &= ~current_umask(); |
463c3197 DH |
2040 | error = may_mknod(mode); |
2041 | if (error) | |
2042 | goto out_dput; | |
2043 | error = mnt_want_write(nd.path.mnt); | |
2044 | if (error) | |
2045 | goto out_dput; | |
be6d3e56 KT |
2046 | error = security_path_mknod(&nd.path, dentry, mode, dev); |
2047 | if (error) | |
2048 | goto out_drop_write; | |
463c3197 | 2049 | switch (mode & S_IFMT) { |
1da177e4 | 2050 | case 0: case S_IFREG: |
4ac91378 | 2051 | error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd); |
1da177e4 LT |
2052 | break; |
2053 | case S_IFCHR: case S_IFBLK: | |
4ac91378 | 2054 | error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode, |
1da177e4 LT |
2055 | new_decode_dev(dev)); |
2056 | break; | |
2057 | case S_IFIFO: case S_IFSOCK: | |
4ac91378 | 2058 | error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0); |
1da177e4 | 2059 | break; |
1da177e4 | 2060 | } |
be6d3e56 | 2061 | out_drop_write: |
463c3197 DH |
2062 | mnt_drop_write(nd.path.mnt); |
2063 | out_dput: | |
2064 | dput(dentry); | |
2065 | out_unlock: | |
4ac91378 | 2066 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
1d957f9b | 2067 | path_put(&nd.path); |
1da177e4 LT |
2068 | putname(tmp); |
2069 | ||
2070 | return error; | |
2071 | } | |
2072 | ||
3480b257 | 2073 | SYSCALL_DEFINE3(mknod, const char __user *, filename, int, mode, unsigned, dev) |
5590ff0d UD |
2074 | { |
2075 | return sys_mknodat(AT_FDCWD, filename, mode, dev); | |
2076 | } | |
2077 | ||
1da177e4 LT |
2078 | int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
2079 | { | |
a95164d9 | 2080 | int error = may_create(dir, dentry); |
1da177e4 LT |
2081 | |
2082 | if (error) | |
2083 | return error; | |
2084 | ||
acfa4380 | 2085 | if (!dir->i_op->mkdir) |
1da177e4 LT |
2086 | return -EPERM; |
2087 | ||
2088 | mode &= (S_IRWXUGO|S_ISVTX); | |
2089 | error = security_inode_mkdir(dir, dentry, mode); | |
2090 | if (error) | |
2091 | return error; | |
2092 | ||
9e3509e2 | 2093 | vfs_dq_init(dir); |
1da177e4 | 2094 | error = dir->i_op->mkdir(dir, dentry, mode); |
a74574aa | 2095 | if (!error) |
f38aa942 | 2096 | fsnotify_mkdir(dir, dentry); |
1da177e4 LT |
2097 | return error; |
2098 | } | |
2099 | ||
2e4d0924 | 2100 | SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, int, mode) |
1da177e4 LT |
2101 | { |
2102 | int error = 0; | |
2103 | char * tmp; | |
6902d925 DH |
2104 | struct dentry *dentry; |
2105 | struct nameidata nd; | |
1da177e4 | 2106 | |
2ad94ae6 AV |
2107 | error = user_path_parent(dfd, pathname, &nd, &tmp); |
2108 | if (error) | |
6902d925 | 2109 | goto out_err; |
1da177e4 | 2110 | |
6902d925 DH |
2111 | dentry = lookup_create(&nd, 1); |
2112 | error = PTR_ERR(dentry); | |
2113 | if (IS_ERR(dentry)) | |
2114 | goto out_unlock; | |
1da177e4 | 2115 | |
4ac91378 | 2116 | if (!IS_POSIXACL(nd.path.dentry->d_inode)) |
ce3b0f8d | 2117 | mode &= ~current_umask(); |
463c3197 DH |
2118 | error = mnt_want_write(nd.path.mnt); |
2119 | if (error) | |
2120 | goto out_dput; | |
be6d3e56 KT |
2121 | error = security_path_mkdir(&nd.path, dentry, mode); |
2122 | if (error) | |
2123 | goto out_drop_write; | |
4ac91378 | 2124 | error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode); |
be6d3e56 | 2125 | out_drop_write: |
463c3197 DH |
2126 | mnt_drop_write(nd.path.mnt); |
2127 | out_dput: | |
6902d925 DH |
2128 | dput(dentry); |
2129 | out_unlock: | |
4ac91378 | 2130 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
1d957f9b | 2131 | path_put(&nd.path); |
6902d925 DH |
2132 | putname(tmp); |
2133 | out_err: | |
1da177e4 LT |
2134 | return error; |
2135 | } | |
2136 | ||
3cdad428 | 2137 | SYSCALL_DEFINE2(mkdir, const char __user *, pathname, int, mode) |
5590ff0d UD |
2138 | { |
2139 | return sys_mkdirat(AT_FDCWD, pathname, mode); | |
2140 | } | |
2141 | ||
1da177e4 LT |
2142 | /* |
2143 | * We try to drop the dentry early: we should have | |
2144 | * a usage count of 2 if we're the only user of this | |
2145 | * dentry, and if that is true (possibly after pruning | |
2146 | * the dcache), then we drop the dentry now. | |
2147 | * | |
2148 | * A low-level filesystem can, if it choses, legally | |
2149 | * do a | |
2150 | * | |
2151 | * if (!d_unhashed(dentry)) | |
2152 | * return -EBUSY; | |
2153 | * | |
2154 | * if it cannot handle the case of removing a directory | |
2155 | * that is still in use by something else.. | |
2156 | */ | |
2157 | void dentry_unhash(struct dentry *dentry) | |
2158 | { | |
2159 | dget(dentry); | |
dc168427 | 2160 | shrink_dcache_parent(dentry); |
1da177e4 LT |
2161 | spin_lock(&dcache_lock); |
2162 | spin_lock(&dentry->d_lock); | |
2163 | if (atomic_read(&dentry->d_count) == 2) | |
2164 | __d_drop(dentry); | |
2165 | spin_unlock(&dentry->d_lock); | |
2166 | spin_unlock(&dcache_lock); | |
2167 | } | |
2168 | ||
2169 | int vfs_rmdir(struct inode *dir, struct dentry *dentry) | |
2170 | { | |
2171 | int error = may_delete(dir, dentry, 1); | |
2172 | ||
2173 | if (error) | |
2174 | return error; | |
2175 | ||
acfa4380 | 2176 | if (!dir->i_op->rmdir) |
1da177e4 LT |
2177 | return -EPERM; |
2178 | ||
9e3509e2 | 2179 | vfs_dq_init(dir); |
1da177e4 | 2180 | |
1b1dcc1b | 2181 | mutex_lock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
2182 | dentry_unhash(dentry); |
2183 | if (d_mountpoint(dentry)) | |
2184 | error = -EBUSY; | |
2185 | else { | |
2186 | error = security_inode_rmdir(dir, dentry); | |
2187 | if (!error) { | |
2188 | error = dir->i_op->rmdir(dir, dentry); | |
2189 | if (!error) | |
2190 | dentry->d_inode->i_flags |= S_DEAD; | |
2191 | } | |
2192 | } | |
1b1dcc1b | 2193 | mutex_unlock(&dentry->d_inode->i_mutex); |
1da177e4 | 2194 | if (!error) { |
1da177e4 LT |
2195 | d_delete(dentry); |
2196 | } | |
2197 | dput(dentry); | |
2198 | ||
2199 | return error; | |
2200 | } | |
2201 | ||
5590ff0d | 2202 | static long do_rmdir(int dfd, const char __user *pathname) |
1da177e4 LT |
2203 | { |
2204 | int error = 0; | |
2205 | char * name; | |
2206 | struct dentry *dentry; | |
2207 | struct nameidata nd; | |
2208 | ||
2ad94ae6 | 2209 | error = user_path_parent(dfd, pathname, &nd, &name); |
1da177e4 | 2210 | if (error) |
2ad94ae6 | 2211 | return error; |
1da177e4 LT |
2212 | |
2213 | switch(nd.last_type) { | |
0612d9fb OH |
2214 | case LAST_DOTDOT: |
2215 | error = -ENOTEMPTY; | |
2216 | goto exit1; | |
2217 | case LAST_DOT: | |
2218 | error = -EINVAL; | |
2219 | goto exit1; | |
2220 | case LAST_ROOT: | |
2221 | error = -EBUSY; | |
2222 | goto exit1; | |
1da177e4 | 2223 | } |
0612d9fb OH |
2224 | |
2225 | nd.flags &= ~LOOKUP_PARENT; | |
2226 | ||
4ac91378 | 2227 | mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
49705b77 | 2228 | dentry = lookup_hash(&nd); |
1da177e4 | 2229 | error = PTR_ERR(dentry); |
6902d925 DH |
2230 | if (IS_ERR(dentry)) |
2231 | goto exit2; | |
0622753b DH |
2232 | error = mnt_want_write(nd.path.mnt); |
2233 | if (error) | |
2234 | goto exit3; | |
be6d3e56 KT |
2235 | error = security_path_rmdir(&nd.path, dentry); |
2236 | if (error) | |
2237 | goto exit4; | |
4ac91378 | 2238 | error = vfs_rmdir(nd.path.dentry->d_inode, dentry); |
be6d3e56 | 2239 | exit4: |
0622753b DH |
2240 | mnt_drop_write(nd.path.mnt); |
2241 | exit3: | |
6902d925 DH |
2242 | dput(dentry); |
2243 | exit2: | |
4ac91378 | 2244 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
1da177e4 | 2245 | exit1: |
1d957f9b | 2246 | path_put(&nd.path); |
1da177e4 LT |
2247 | putname(name); |
2248 | return error; | |
2249 | } | |
2250 | ||
3cdad428 | 2251 | SYSCALL_DEFINE1(rmdir, const char __user *, pathname) |
5590ff0d UD |
2252 | { |
2253 | return do_rmdir(AT_FDCWD, pathname); | |
2254 | } | |
2255 | ||
1da177e4 LT |
2256 | int vfs_unlink(struct inode *dir, struct dentry *dentry) |
2257 | { | |
2258 | int error = may_delete(dir, dentry, 0); | |
2259 | ||
2260 | if (error) | |
2261 | return error; | |
2262 | ||
acfa4380 | 2263 | if (!dir->i_op->unlink) |
1da177e4 LT |
2264 | return -EPERM; |
2265 | ||
9e3509e2 | 2266 | vfs_dq_init(dir); |
1da177e4 | 2267 | |
1b1dcc1b | 2268 | mutex_lock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
2269 | if (d_mountpoint(dentry)) |
2270 | error = -EBUSY; | |
2271 | else { | |
2272 | error = security_inode_unlink(dir, dentry); | |
2273 | if (!error) | |
2274 | error = dir->i_op->unlink(dir, dentry); | |
2275 | } | |
1b1dcc1b | 2276 | mutex_unlock(&dentry->d_inode->i_mutex); |
1da177e4 LT |
2277 | |
2278 | /* We don't d_delete() NFS sillyrenamed files--they still exist. */ | |
2279 | if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { | |
ece95912 | 2280 | fsnotify_link_count(dentry->d_inode); |
e234f35c | 2281 | d_delete(dentry); |
1da177e4 | 2282 | } |
0eeca283 | 2283 | |
1da177e4 LT |
2284 | return error; |
2285 | } | |
2286 | ||
2287 | /* | |
2288 | * Make sure that the actual truncation of the file will occur outside its | |
1b1dcc1b | 2289 | * directory's i_mutex. Truncate can take a long time if there is a lot of |
1da177e4 LT |
2290 | * writeout happening, and we don't want to prevent access to the directory |
2291 | * while waiting on the I/O. | |
2292 | */ | |
5590ff0d | 2293 | static long do_unlinkat(int dfd, const char __user *pathname) |
1da177e4 | 2294 | { |
2ad94ae6 AV |
2295 | int error; |
2296 | char *name; | |
1da177e4 LT |
2297 | struct dentry *dentry; |
2298 | struct nameidata nd; | |
2299 | struct inode *inode = NULL; | |
2300 | ||
2ad94ae6 | 2301 | error = user_path_parent(dfd, pathname, &nd, &name); |
1da177e4 | 2302 | if (error) |
2ad94ae6 AV |
2303 | return error; |
2304 | ||
1da177e4 LT |
2305 | error = -EISDIR; |
2306 | if (nd.last_type != LAST_NORM) | |
2307 | goto exit1; | |
0612d9fb OH |
2308 | |
2309 | nd.flags &= ~LOOKUP_PARENT; | |
2310 | ||
4ac91378 | 2311 | mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
49705b77 | 2312 | dentry = lookup_hash(&nd); |
1da177e4 LT |
2313 | error = PTR_ERR(dentry); |
2314 | if (!IS_ERR(dentry)) { | |
2315 | /* Why not before? Because we want correct error value */ | |
2316 | if (nd.last.name[nd.last.len]) | |
2317 | goto slashes; | |
2318 | inode = dentry->d_inode; | |
2319 | if (inode) | |
2320 | atomic_inc(&inode->i_count); | |
0622753b DH |
2321 | error = mnt_want_write(nd.path.mnt); |
2322 | if (error) | |
2323 | goto exit2; | |
be6d3e56 KT |
2324 | error = security_path_unlink(&nd.path, dentry); |
2325 | if (error) | |
2326 | goto exit3; | |
4ac91378 | 2327 | error = vfs_unlink(nd.path.dentry->d_inode, dentry); |
be6d3e56 | 2328 | exit3: |
0622753b | 2329 | mnt_drop_write(nd.path.mnt); |
1da177e4 LT |
2330 | exit2: |
2331 | dput(dentry); | |
2332 | } | |
4ac91378 | 2333 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
1da177e4 LT |
2334 | if (inode) |
2335 | iput(inode); /* truncate the inode here */ | |
2336 | exit1: | |
1d957f9b | 2337 | path_put(&nd.path); |
1da177e4 LT |
2338 | putname(name); |
2339 | return error; | |
2340 | ||
2341 | slashes: | |
2342 | error = !dentry->d_inode ? -ENOENT : | |
2343 | S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; | |
2344 | goto exit2; | |
2345 | } | |
2346 | ||
2e4d0924 | 2347 | SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag) |
5590ff0d UD |
2348 | { |
2349 | if ((flag & ~AT_REMOVEDIR) != 0) | |
2350 | return -EINVAL; | |
2351 | ||
2352 | if (flag & AT_REMOVEDIR) | |
2353 | return do_rmdir(dfd, pathname); | |
2354 | ||
2355 | return do_unlinkat(dfd, pathname); | |
2356 | } | |
2357 | ||
3480b257 | 2358 | SYSCALL_DEFINE1(unlink, const char __user *, pathname) |
5590ff0d UD |
2359 | { |
2360 | return do_unlinkat(AT_FDCWD, pathname); | |
2361 | } | |
2362 | ||
db2e747b | 2363 | int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) |
1da177e4 | 2364 | { |
a95164d9 | 2365 | int error = may_create(dir, dentry); |
1da177e4 LT |
2366 | |
2367 | if (error) | |
2368 | return error; | |
2369 | ||
acfa4380 | 2370 | if (!dir->i_op->symlink) |
1da177e4 LT |
2371 | return -EPERM; |
2372 | ||
2373 | error = security_inode_symlink(dir, dentry, oldname); | |
2374 | if (error) | |
2375 | return error; | |
2376 | ||
9e3509e2 | 2377 | vfs_dq_init(dir); |
1da177e4 | 2378 | error = dir->i_op->symlink(dir, dentry, oldname); |
a74574aa | 2379 | if (!error) |
f38aa942 | 2380 | fsnotify_create(dir, dentry); |
1da177e4 LT |
2381 | return error; |
2382 | } | |
2383 | ||
2e4d0924 HC |
2384 | SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, |
2385 | int, newdfd, const char __user *, newname) | |
1da177e4 | 2386 | { |
2ad94ae6 AV |
2387 | int error; |
2388 | char *from; | |
2389 | char *to; | |
6902d925 DH |
2390 | struct dentry *dentry; |
2391 | struct nameidata nd; | |
1da177e4 LT |
2392 | |
2393 | from = getname(oldname); | |
2ad94ae6 | 2394 | if (IS_ERR(from)) |
1da177e4 | 2395 | return PTR_ERR(from); |
1da177e4 | 2396 | |
2ad94ae6 | 2397 | error = user_path_parent(newdfd, newname, &nd, &to); |
6902d925 | 2398 | if (error) |
2ad94ae6 AV |
2399 | goto out_putname; |
2400 | ||
6902d925 DH |
2401 | dentry = lookup_create(&nd, 0); |
2402 | error = PTR_ERR(dentry); | |
2403 | if (IS_ERR(dentry)) | |
2404 | goto out_unlock; | |
2405 | ||
75c3f29d DH |
2406 | error = mnt_want_write(nd.path.mnt); |
2407 | if (error) | |
2408 | goto out_dput; | |
be6d3e56 KT |
2409 | error = security_path_symlink(&nd.path, dentry, from); |
2410 | if (error) | |
2411 | goto out_drop_write; | |
db2e747b | 2412 | error = vfs_symlink(nd.path.dentry->d_inode, dentry, from); |
be6d3e56 | 2413 | out_drop_write: |
75c3f29d DH |
2414 | mnt_drop_write(nd.path.mnt); |
2415 | out_dput: | |
6902d925 DH |
2416 | dput(dentry); |
2417 | out_unlock: | |
4ac91378 | 2418 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
1d957f9b | 2419 | path_put(&nd.path); |
6902d925 DH |
2420 | putname(to); |
2421 | out_putname: | |
1da177e4 LT |
2422 | putname(from); |
2423 | return error; | |
2424 | } | |
2425 | ||
3480b257 | 2426 | SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) |
5590ff0d UD |
2427 | { |
2428 | return sys_symlinkat(oldname, AT_FDCWD, newname); | |
2429 | } | |
2430 | ||
1da177e4 LT |
2431 | int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) |
2432 | { | |
2433 | struct inode *inode = old_dentry->d_inode; | |
2434 | int error; | |
2435 | ||
2436 | if (!inode) | |
2437 | return -ENOENT; | |
2438 | ||
a95164d9 | 2439 | error = may_create(dir, new_dentry); |
1da177e4 LT |
2440 | if (error) |
2441 | return error; | |
2442 | ||
2443 | if (dir->i_sb != inode->i_sb) | |
2444 | return -EXDEV; | |
2445 | ||
2446 | /* | |
2447 | * A link to an append-only or immutable file cannot be created. | |
2448 | */ | |
2449 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) | |
2450 | return -EPERM; | |
acfa4380 | 2451 | if (!dir->i_op->link) |
1da177e4 | 2452 | return -EPERM; |
7e79eedb | 2453 | if (S_ISDIR(inode->i_mode)) |
1da177e4 LT |
2454 | return -EPERM; |
2455 | ||
2456 | error = security_inode_link(old_dentry, dir, new_dentry); | |
2457 | if (error) | |
2458 | return error; | |
2459 | ||
7e79eedb | 2460 | mutex_lock(&inode->i_mutex); |
9e3509e2 | 2461 | vfs_dq_init(dir); |
1da177e4 | 2462 | error = dir->i_op->link(old_dentry, dir, new_dentry); |
7e79eedb | 2463 | mutex_unlock(&inode->i_mutex); |
e31e14ec | 2464 | if (!error) |
7e79eedb | 2465 | fsnotify_link(dir, inode, new_dentry); |
1da177e4 LT |
2466 | return error; |
2467 | } | |
2468 | ||
2469 | /* | |
2470 | * Hardlinks are often used in delicate situations. We avoid | |
2471 | * security-related surprises by not following symlinks on the | |
2472 | * newname. --KAB | |
2473 | * | |
2474 | * We don't follow them on the oldname either to be compatible | |
2475 | * with linux 2.0, and to avoid hard-linking to directories | |
2476 | * and other special files. --ADM | |
2477 | */ | |
2e4d0924 HC |
2478 | SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, |
2479 | int, newdfd, const char __user *, newname, int, flags) | |
1da177e4 LT |
2480 | { |
2481 | struct dentry *new_dentry; | |
2d8f3038 AV |
2482 | struct nameidata nd; |
2483 | struct path old_path; | |
1da177e4 | 2484 | int error; |
2ad94ae6 | 2485 | char *to; |
1da177e4 | 2486 | |
45c9b11a | 2487 | if ((flags & ~AT_SYMLINK_FOLLOW) != 0) |
c04030e1 UD |
2488 | return -EINVAL; |
2489 | ||
2d8f3038 AV |
2490 | error = user_path_at(olddfd, oldname, |
2491 | flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0, | |
2492 | &old_path); | |
1da177e4 | 2493 | if (error) |
2ad94ae6 AV |
2494 | return error; |
2495 | ||
2496 | error = user_path_parent(newdfd, newname, &nd, &to); | |
1da177e4 LT |
2497 | if (error) |
2498 | goto out; | |
2499 | error = -EXDEV; | |
2d8f3038 | 2500 | if (old_path.mnt != nd.path.mnt) |
1da177e4 LT |
2501 | goto out_release; |
2502 | new_dentry = lookup_create(&nd, 0); | |
2503 | error = PTR_ERR(new_dentry); | |
6902d925 DH |
2504 | if (IS_ERR(new_dentry)) |
2505 | goto out_unlock; | |
75c3f29d DH |
2506 | error = mnt_want_write(nd.path.mnt); |
2507 | if (error) | |
2508 | goto out_dput; | |
be6d3e56 KT |
2509 | error = security_path_link(old_path.dentry, &nd.path, new_dentry); |
2510 | if (error) | |
2511 | goto out_drop_write; | |
2d8f3038 | 2512 | error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); |
be6d3e56 | 2513 | out_drop_write: |
75c3f29d DH |
2514 | mnt_drop_write(nd.path.mnt); |
2515 | out_dput: | |
6902d925 DH |
2516 | dput(new_dentry); |
2517 | out_unlock: | |
4ac91378 | 2518 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
1da177e4 | 2519 | out_release: |
1d957f9b | 2520 | path_put(&nd.path); |
2ad94ae6 | 2521 | putname(to); |
1da177e4 | 2522 | out: |
2d8f3038 | 2523 | path_put(&old_path); |
1da177e4 LT |
2524 | |
2525 | return error; | |
2526 | } | |
2527 | ||
3480b257 | 2528 | SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) |
5590ff0d | 2529 | { |
c04030e1 | 2530 | return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); |
5590ff0d UD |
2531 | } |
2532 | ||
1da177e4 LT |
2533 | /* |
2534 | * The worst of all namespace operations - renaming directory. "Perverted" | |
2535 | * doesn't even start to describe it. Somebody in UCB had a heck of a trip... | |
2536 | * Problems: | |
2537 | * a) we can get into loop creation. Check is done in is_subdir(). | |
2538 | * b) race potential - two innocent renames can create a loop together. | |
2539 | * That's where 4.4 screws up. Current fix: serialization on | |
a11f3a05 | 2540 | * sb->s_vfs_rename_mutex. We might be more accurate, but that's another |
1da177e4 LT |
2541 | * story. |
2542 | * c) we have to lock _three_ objects - parents and victim (if it exists). | |
1b1dcc1b | 2543 | * And that - after we got ->i_mutex on parents (until then we don't know |
1da177e4 LT |
2544 | * whether the target exists). Solution: try to be smart with locking |
2545 | * order for inodes. We rely on the fact that tree topology may change | |
a11f3a05 | 2546 | * only under ->s_vfs_rename_mutex _and_ that parent of the object we |
1da177e4 LT |
2547 | * move will be locked. Thus we can rank directories by the tree |
2548 | * (ancestors first) and rank all non-directories after them. | |
2549 | * That works since everybody except rename does "lock parent, lookup, | |
a11f3a05 | 2550 | * lock child" and rename is under ->s_vfs_rename_mutex. |
1da177e4 LT |
2551 | * HOWEVER, it relies on the assumption that any object with ->lookup() |
2552 | * has no more than 1 dentry. If "hybrid" objects will ever appear, | |
2553 | * we'd better make sure that there's no link(2) for them. | |
2554 | * d) some filesystems don't support opened-but-unlinked directories, | |
2555 | * either because of layout or because they are not ready to deal with | |
2556 | * all cases correctly. The latter will be fixed (taking this sort of | |
2557 | * stuff into VFS), but the former is not going away. Solution: the same | |
2558 | * trick as in rmdir(). | |
2559 | * e) conversion from fhandle to dentry may come in the wrong moment - when | |
1b1dcc1b | 2560 | * we are removing the target. Solution: we will have to grab ->i_mutex |
1da177e4 | 2561 | * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on |
1b1dcc1b | 2562 | * ->i_mutex on parents, which works but leads to some truely excessive |
1da177e4 LT |
2563 | * locking]. |
2564 | */ | |
75c96f85 AB |
2565 | static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, |
2566 | struct inode *new_dir, struct dentry *new_dentry) | |
1da177e4 LT |
2567 | { |
2568 | int error = 0; | |
2569 | struct inode *target; | |
2570 | ||
2571 | /* | |
2572 | * If we are going to change the parent - check write permissions, | |
2573 | * we'll need to flip '..'. | |
2574 | */ | |
2575 | if (new_dir != old_dir) { | |
f419a2e3 | 2576 | error = inode_permission(old_dentry->d_inode, MAY_WRITE); |
1da177e4 LT |
2577 | if (error) |
2578 | return error; | |
2579 | } | |
2580 | ||
2581 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); | |
2582 | if (error) | |
2583 | return error; | |
2584 | ||
2585 | target = new_dentry->d_inode; | |
2586 | if (target) { | |
1b1dcc1b | 2587 | mutex_lock(&target->i_mutex); |
1da177e4 LT |
2588 | dentry_unhash(new_dentry); |
2589 | } | |
2590 | if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) | |
2591 | error = -EBUSY; | |
2592 | else | |
2593 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); | |
2594 | if (target) { | |
2595 | if (!error) | |
2596 | target->i_flags |= S_DEAD; | |
1b1dcc1b | 2597 | mutex_unlock(&target->i_mutex); |
1da177e4 LT |
2598 | if (d_unhashed(new_dentry)) |
2599 | d_rehash(new_dentry); | |
2600 | dput(new_dentry); | |
2601 | } | |
e31e14ec | 2602 | if (!error) |
349457cc MF |
2603 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
2604 | d_move(old_dentry,new_dentry); | |
1da177e4 LT |
2605 | return error; |
2606 | } | |
2607 | ||
75c96f85 AB |
2608 | static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, |
2609 | struct inode *new_dir, struct dentry *new_dentry) | |
1da177e4 LT |
2610 | { |
2611 | struct inode *target; | |
2612 | int error; | |
2613 | ||
2614 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); | |
2615 | if (error) | |
2616 | return error; | |
2617 | ||
2618 | dget(new_dentry); | |
2619 | target = new_dentry->d_inode; | |
2620 | if (target) | |
1b1dcc1b | 2621 | mutex_lock(&target->i_mutex); |
1da177e4 LT |
2622 | if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) |
2623 | error = -EBUSY; | |
2624 | else | |
2625 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); | |
2626 | if (!error) { | |
349457cc | 2627 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
1da177e4 | 2628 | d_move(old_dentry, new_dentry); |
1da177e4 LT |
2629 | } |
2630 | if (target) | |
1b1dcc1b | 2631 | mutex_unlock(&target->i_mutex); |
1da177e4 LT |
2632 | dput(new_dentry); |
2633 | return error; | |
2634 | } | |
2635 | ||
2636 | int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, | |
2637 | struct inode *new_dir, struct dentry *new_dentry) | |
2638 | { | |
2639 | int error; | |
2640 | int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); | |
0eeca283 | 2641 | const char *old_name; |
1da177e4 LT |
2642 | |
2643 | if (old_dentry->d_inode == new_dentry->d_inode) | |
2644 | return 0; | |
2645 | ||
2646 | error = may_delete(old_dir, old_dentry, is_dir); | |
2647 | if (error) | |
2648 | return error; | |
2649 | ||
2650 | if (!new_dentry->d_inode) | |
a95164d9 | 2651 | error = may_create(new_dir, new_dentry); |
1da177e4 LT |
2652 | else |
2653 | error = may_delete(new_dir, new_dentry, is_dir); | |
2654 | if (error) | |
2655 | return error; | |
2656 | ||
acfa4380 | 2657 | if (!old_dir->i_op->rename) |
1da177e4 LT |
2658 | return -EPERM; |
2659 | ||
9e3509e2 JK |
2660 | vfs_dq_init(old_dir); |
2661 | vfs_dq_init(new_dir); | |
1da177e4 | 2662 | |
0eeca283 RL |
2663 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); |
2664 | ||
1da177e4 LT |
2665 | if (is_dir) |
2666 | error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); | |
2667 | else | |
2668 | error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); | |
2669 | if (!error) { | |
0eeca283 | 2670 | const char *new_name = old_dentry->d_name.name; |
89204c40 | 2671 | fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir, |
5a190ae6 | 2672 | new_dentry->d_inode, old_dentry); |
1da177e4 | 2673 | } |
0eeca283 RL |
2674 | fsnotify_oldname_free(old_name); |
2675 | ||
1da177e4 LT |
2676 | return error; |
2677 | } | |
2678 | ||
2e4d0924 HC |
2679 | SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, |
2680 | int, newdfd, const char __user *, newname) | |
1da177e4 | 2681 | { |
2ad94ae6 AV |
2682 | struct dentry *old_dir, *new_dir; |
2683 | struct dentry *old_dentry, *new_dentry; | |
2684 | struct dentry *trap; | |
1da177e4 | 2685 | struct nameidata oldnd, newnd; |
2ad94ae6 AV |
2686 | char *from; |
2687 | char *to; | |
2688 | int error; | |
1da177e4 | 2689 | |
2ad94ae6 | 2690 | error = user_path_parent(olddfd, oldname, &oldnd, &from); |
1da177e4 LT |
2691 | if (error) |
2692 | goto exit; | |
2693 | ||
2ad94ae6 | 2694 | error = user_path_parent(newdfd, newname, &newnd, &to); |
1da177e4 LT |
2695 | if (error) |
2696 | goto exit1; | |
2697 | ||
2698 | error = -EXDEV; | |
4ac91378 | 2699 | if (oldnd.path.mnt != newnd.path.mnt) |
1da177e4 LT |
2700 | goto exit2; |
2701 | ||
4ac91378 | 2702 | old_dir = oldnd.path.dentry; |
1da177e4 LT |
2703 | error = -EBUSY; |
2704 | if (oldnd.last_type != LAST_NORM) | |
2705 | goto exit2; | |
2706 | ||
4ac91378 | 2707 | new_dir = newnd.path.dentry; |
1da177e4 LT |
2708 | if (newnd.last_type != LAST_NORM) |
2709 | goto exit2; | |
2710 | ||
0612d9fb OH |
2711 | oldnd.flags &= ~LOOKUP_PARENT; |
2712 | newnd.flags &= ~LOOKUP_PARENT; | |
4e9ed2f8 | 2713 | newnd.flags |= LOOKUP_RENAME_TARGET; |
0612d9fb | 2714 | |
1da177e4 LT |
2715 | trap = lock_rename(new_dir, old_dir); |
2716 | ||
49705b77 | 2717 | old_dentry = lookup_hash(&oldnd); |
1da177e4 LT |
2718 | error = PTR_ERR(old_dentry); |
2719 | if (IS_ERR(old_dentry)) | |
2720 | goto exit3; | |
2721 | /* source must exist */ | |
2722 | error = -ENOENT; | |
2723 | if (!old_dentry->d_inode) | |
2724 | goto exit4; | |
2725 | /* unless the source is a directory trailing slashes give -ENOTDIR */ | |
2726 | if (!S_ISDIR(old_dentry->d_inode->i_mode)) { | |
2727 | error = -ENOTDIR; | |
2728 | if (oldnd.last.name[oldnd.last.len]) | |
2729 | goto exit4; | |
2730 | if (newnd.last.name[newnd.last.len]) | |
2731 | goto exit4; | |
2732 | } | |
2733 | /* source should not be ancestor of target */ | |
2734 | error = -EINVAL; | |
2735 | if (old_dentry == trap) | |
2736 | goto exit4; | |
49705b77 | 2737 | new_dentry = lookup_hash(&newnd); |
1da177e4 LT |
2738 | error = PTR_ERR(new_dentry); |
2739 | if (IS_ERR(new_dentry)) | |
2740 | goto exit4; | |
2741 | /* target should not be an ancestor of source */ | |
2742 | error = -ENOTEMPTY; | |
2743 | if (new_dentry == trap) | |
2744 | goto exit5; | |
2745 | ||
9079b1eb DH |
2746 | error = mnt_want_write(oldnd.path.mnt); |
2747 | if (error) | |
2748 | goto exit5; | |
be6d3e56 KT |
2749 | error = security_path_rename(&oldnd.path, old_dentry, |
2750 | &newnd.path, new_dentry); | |
2751 | if (error) | |
2752 | goto exit6; | |
1da177e4 LT |
2753 | error = vfs_rename(old_dir->d_inode, old_dentry, |
2754 | new_dir->d_inode, new_dentry); | |
be6d3e56 | 2755 | exit6: |
9079b1eb | 2756 | mnt_drop_write(oldnd.path.mnt); |
1da177e4 LT |
2757 | exit5: |
2758 | dput(new_dentry); | |
2759 | exit4: | |
2760 | dput(old_dentry); | |
2761 | exit3: | |
2762 | unlock_rename(new_dir, old_dir); | |
2763 | exit2: | |
1d957f9b | 2764 | path_put(&newnd.path); |
2ad94ae6 | 2765 | putname(to); |
1da177e4 | 2766 | exit1: |
1d957f9b | 2767 | path_put(&oldnd.path); |
1da177e4 | 2768 | putname(from); |
2ad94ae6 | 2769 | exit: |
1da177e4 LT |
2770 | return error; |
2771 | } | |
2772 | ||
a26eab24 | 2773 | SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) |
5590ff0d UD |
2774 | { |
2775 | return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); | |
2776 | } | |
2777 | ||
1da177e4 LT |
2778 | int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) |
2779 | { | |
2780 | int len; | |
2781 | ||
2782 | len = PTR_ERR(link); | |
2783 | if (IS_ERR(link)) | |
2784 | goto out; | |
2785 | ||
2786 | len = strlen(link); | |
2787 | if (len > (unsigned) buflen) | |
2788 | len = buflen; | |
2789 | if (copy_to_user(buffer, link, len)) | |
2790 | len = -EFAULT; | |
2791 | out: | |
2792 | return len; | |
2793 | } | |
2794 | ||
2795 | /* | |
2796 | * A helper for ->readlink(). This should be used *ONLY* for symlinks that | |
2797 | * have ->follow_link() touching nd only in nd_set_link(). Using (or not | |
2798 | * using) it for any given inode is up to filesystem. | |
2799 | */ | |
2800 | int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) | |
2801 | { | |
2802 | struct nameidata nd; | |
cc314eef | 2803 | void *cookie; |
694a1764 | 2804 | int res; |
cc314eef | 2805 | |
1da177e4 | 2806 | nd.depth = 0; |
cc314eef | 2807 | cookie = dentry->d_inode->i_op->follow_link(dentry, &nd); |
694a1764 MS |
2808 | if (IS_ERR(cookie)) |
2809 | return PTR_ERR(cookie); | |
2810 | ||
2811 | res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd)); | |
2812 | if (dentry->d_inode->i_op->put_link) | |
2813 | dentry->d_inode->i_op->put_link(dentry, &nd, cookie); | |
2814 | return res; | |
1da177e4 LT |
2815 | } |
2816 | ||
2817 | int vfs_follow_link(struct nameidata *nd, const char *link) | |
2818 | { | |
2819 | return __vfs_follow_link(nd, link); | |
2820 | } | |
2821 | ||
2822 | /* get the link contents into pagecache */ | |
2823 | static char *page_getlink(struct dentry * dentry, struct page **ppage) | |
2824 | { | |
ebd09abb DG |
2825 | char *kaddr; |
2826 | struct page *page; | |
1da177e4 | 2827 | struct address_space *mapping = dentry->d_inode->i_mapping; |
090d2b18 | 2828 | page = read_mapping_page(mapping, 0, NULL); |
1da177e4 | 2829 | if (IS_ERR(page)) |
6fe6900e | 2830 | return (char*)page; |
1da177e4 | 2831 | *ppage = page; |
ebd09abb DG |
2832 | kaddr = kmap(page); |
2833 | nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); | |
2834 | return kaddr; | |
1da177e4 LT |
2835 | } |
2836 | ||
2837 | int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) | |
2838 | { | |
2839 | struct page *page = NULL; | |
2840 | char *s = page_getlink(dentry, &page); | |
2841 | int res = vfs_readlink(dentry,buffer,buflen,s); | |
2842 | if (page) { | |
2843 | kunmap(page); | |
2844 | page_cache_release(page); | |
2845 | } | |
2846 | return res; | |
2847 | } | |
2848 | ||
cc314eef | 2849 | void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 2850 | { |
cc314eef | 2851 | struct page *page = NULL; |
1da177e4 | 2852 | nd_set_link(nd, page_getlink(dentry, &page)); |
cc314eef | 2853 | return page; |
1da177e4 LT |
2854 | } |
2855 | ||
cc314eef | 2856 | void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 | 2857 | { |
cc314eef LT |
2858 | struct page *page = cookie; |
2859 | ||
2860 | if (page) { | |
1da177e4 LT |
2861 | kunmap(page); |
2862 | page_cache_release(page); | |
1da177e4 LT |
2863 | } |
2864 | } | |
2865 | ||
54566b2c NP |
2866 | /* |
2867 | * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS | |
2868 | */ | |
2869 | int __page_symlink(struct inode *inode, const char *symname, int len, int nofs) | |
1da177e4 LT |
2870 | { |
2871 | struct address_space *mapping = inode->i_mapping; | |
0adb25d2 | 2872 | struct page *page; |
afddba49 | 2873 | void *fsdata; |
beb497ab | 2874 | int err; |
1da177e4 | 2875 | char *kaddr; |
54566b2c NP |
2876 | unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE; |
2877 | if (nofs) | |
2878 | flags |= AOP_FLAG_NOFS; | |
1da177e4 | 2879 | |
7e53cac4 | 2880 | retry: |
afddba49 | 2881 | err = pagecache_write_begin(NULL, mapping, 0, len-1, |
54566b2c | 2882 | flags, &page, &fsdata); |
1da177e4 | 2883 | if (err) |
afddba49 NP |
2884 | goto fail; |
2885 | ||
1da177e4 LT |
2886 | kaddr = kmap_atomic(page, KM_USER0); |
2887 | memcpy(kaddr, symname, len-1); | |
2888 | kunmap_atomic(kaddr, KM_USER0); | |
afddba49 NP |
2889 | |
2890 | err = pagecache_write_end(NULL, mapping, 0, len-1, len-1, | |
2891 | page, fsdata); | |
1da177e4 LT |
2892 | if (err < 0) |
2893 | goto fail; | |
afddba49 NP |
2894 | if (err < len-1) |
2895 | goto retry; | |
2896 | ||
1da177e4 LT |
2897 | mark_inode_dirty(inode); |
2898 | return 0; | |
1da177e4 LT |
2899 | fail: |
2900 | return err; | |
2901 | } | |
2902 | ||
0adb25d2 KK |
2903 | int page_symlink(struct inode *inode, const char *symname, int len) |
2904 | { | |
2905 | return __page_symlink(inode, symname, len, | |
54566b2c | 2906 | !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS)); |
0adb25d2 KK |
2907 | } |
2908 | ||
92e1d5be | 2909 | const struct inode_operations page_symlink_inode_operations = { |
1da177e4 LT |
2910 | .readlink = generic_readlink, |
2911 | .follow_link = page_follow_link_light, | |
2912 | .put_link = page_put_link, | |
2913 | }; | |
2914 | ||
2d8f3038 | 2915 | EXPORT_SYMBOL(user_path_at); |
1da177e4 LT |
2916 | EXPORT_SYMBOL(follow_down); |
2917 | EXPORT_SYMBOL(follow_up); | |
2918 | EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ | |
2919 | EXPORT_SYMBOL(getname); | |
2920 | EXPORT_SYMBOL(lock_rename); | |
1da177e4 LT |
2921 | EXPORT_SYMBOL(lookup_one_len); |
2922 | EXPORT_SYMBOL(page_follow_link_light); | |
2923 | EXPORT_SYMBOL(page_put_link); | |
2924 | EXPORT_SYMBOL(page_readlink); | |
0adb25d2 | 2925 | EXPORT_SYMBOL(__page_symlink); |
1da177e4 LT |
2926 | EXPORT_SYMBOL(page_symlink); |
2927 | EXPORT_SYMBOL(page_symlink_inode_operations); | |
2928 | EXPORT_SYMBOL(path_lookup); | |
d1811465 | 2929 | EXPORT_SYMBOL(kern_path); |
16f18200 | 2930 | EXPORT_SYMBOL(vfs_path_lookup); |
f419a2e3 | 2931 | EXPORT_SYMBOL(inode_permission); |
8c744fb8 | 2932 | EXPORT_SYMBOL(file_permission); |
1da177e4 LT |
2933 | EXPORT_SYMBOL(unlock_rename); |
2934 | EXPORT_SYMBOL(vfs_create); | |
2935 | EXPORT_SYMBOL(vfs_follow_link); | |
2936 | EXPORT_SYMBOL(vfs_link); | |
2937 | EXPORT_SYMBOL(vfs_mkdir); | |
2938 | EXPORT_SYMBOL(vfs_mknod); | |
2939 | EXPORT_SYMBOL(generic_permission); | |
2940 | EXPORT_SYMBOL(vfs_readlink); | |
2941 | EXPORT_SYMBOL(vfs_rename); | |
2942 | EXPORT_SYMBOL(vfs_rmdir); | |
2943 | EXPORT_SYMBOL(vfs_symlink); | |
2944 | EXPORT_SYMBOL(vfs_unlink); | |
2945 | EXPORT_SYMBOL(dentry_unhash); | |
2946 | EXPORT_SYMBOL(generic_readlink); |