]> git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - fs/ecryptfs/inode.c
check ATTR_SIZE contraints in inode_change_ok
[mirror_ubuntu-zesty-kernel.git] / fs / ecryptfs / inode.c
1 /**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompsion <mcthomps@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 * 02111-1307, USA.
24 */
25
26 #include <linux/file.h>
27 #include <linux/vmalloc.h>
28 #include <linux/pagemap.h>
29 #include <linux/dcache.h>
30 #include <linux/namei.h>
31 #include <linux/mount.h>
32 #include <linux/crypto.h>
33 #include <linux/fs_stack.h>
34 #include <linux/slab.h>
35 #include <asm/unaligned.h>
36 #include "ecryptfs_kernel.h"
37
38 static struct dentry *lock_parent(struct dentry *dentry)
39 {
40 struct dentry *dir;
41
42 dir = dget_parent(dentry);
43 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
44 return dir;
45 }
46
47 static void unlock_dir(struct dentry *dir)
48 {
49 mutex_unlock(&dir->d_inode->i_mutex);
50 dput(dir);
51 }
52
53 /**
54 * ecryptfs_create_underlying_file
55 * @lower_dir_inode: inode of the parent in the lower fs of the new file
56 * @dentry: New file's dentry
57 * @mode: The mode of the new file
58 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
59 *
60 * Creates the file in the lower file system.
61 *
62 * Returns zero on success; non-zero on error condition
63 */
64 static int
65 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
66 struct dentry *dentry, int mode,
67 struct nameidata *nd)
68 {
69 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
70 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
71 struct dentry *dentry_save;
72 struct vfsmount *vfsmount_save;
73 int rc;
74
75 dentry_save = nd->path.dentry;
76 vfsmount_save = nd->path.mnt;
77 nd->path.dentry = lower_dentry;
78 nd->path.mnt = lower_mnt;
79 rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
80 nd->path.dentry = dentry_save;
81 nd->path.mnt = vfsmount_save;
82 return rc;
83 }
84
85 /**
86 * ecryptfs_do_create
87 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
88 * @ecryptfs_dentry: New file's dentry in ecryptfs
89 * @mode: The mode of the new file
90 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
91 *
92 * Creates the underlying file and the eCryptfs inode which will link to
93 * it. It will also update the eCryptfs directory inode to mimic the
94 * stat of the lower directory inode.
95 *
96 * Returns zero on success; non-zero on error condition
97 */
98 static int
99 ecryptfs_do_create(struct inode *directory_inode,
100 struct dentry *ecryptfs_dentry, int mode,
101 struct nameidata *nd)
102 {
103 int rc;
104 struct dentry *lower_dentry;
105 struct dentry *lower_dir_dentry;
106
107 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
108 lower_dir_dentry = lock_parent(lower_dentry);
109 if (IS_ERR(lower_dir_dentry)) {
110 ecryptfs_printk(KERN_ERR, "Error locking directory of "
111 "dentry\n");
112 rc = PTR_ERR(lower_dir_dentry);
113 goto out;
114 }
115 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
116 ecryptfs_dentry, mode, nd);
117 if (rc) {
118 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
119 "rc = [%d]\n", __func__, rc);
120 goto out_lock;
121 }
122 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
123 directory_inode->i_sb, 0);
124 if (rc) {
125 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
126 goto out_lock;
127 }
128 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
129 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
130 out_lock:
131 unlock_dir(lower_dir_dentry);
132 out:
133 return rc;
134 }
135
136 /**
137 * grow_file
138 * @ecryptfs_dentry: the eCryptfs dentry
139 *
140 * This is the code which will grow the file to its correct size.
141 */
142 static int grow_file(struct dentry *ecryptfs_dentry)
143 {
144 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
145 char zero_virt[] = { 0x00 };
146 int rc = 0;
147
148 rc = ecryptfs_write(ecryptfs_inode, zero_virt, 0, 1);
149 i_size_write(ecryptfs_inode, 0);
150 rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
151 ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
152 ECRYPTFS_NEW_FILE;
153 return rc;
154 }
155
156 /**
157 * ecryptfs_initialize_file
158 *
159 * Cause the file to be changed from a basic empty file to an ecryptfs
160 * file with a header and first data page.
161 *
162 * Returns zero on success
163 */
164 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
165 {
166 struct ecryptfs_crypt_stat *crypt_stat =
167 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
168 int rc = 0;
169
170 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
171 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
172 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
173 goto out;
174 }
175 crypt_stat->flags |= ECRYPTFS_NEW_FILE;
176 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
177 rc = ecryptfs_new_file_context(ecryptfs_dentry);
178 if (rc) {
179 ecryptfs_printk(KERN_ERR, "Error creating new file "
180 "context; rc = [%d]\n", rc);
181 goto out;
182 }
183 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
184 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
185 if (rc) {
186 printk(KERN_ERR "%s: Error attempting to initialize "
187 "the persistent file for the dentry with name "
188 "[%s]; rc = [%d]\n", __func__,
189 ecryptfs_dentry->d_name.name, rc);
190 goto out;
191 }
192 }
193 rc = ecryptfs_write_metadata(ecryptfs_dentry);
194 if (rc) {
195 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
196 goto out;
197 }
198 rc = grow_file(ecryptfs_dentry);
199 if (rc)
200 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
201 out:
202 return rc;
203 }
204
205 /**
206 * ecryptfs_create
207 * @dir: The inode of the directory in which to create the file.
208 * @dentry: The eCryptfs dentry
209 * @mode: The mode of the new file.
210 * @nd: nameidata
211 *
212 * Creates a new file.
213 *
214 * Returns zero on success; non-zero on error condition
215 */
216 static int
217 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
218 int mode, struct nameidata *nd)
219 {
220 int rc;
221
222 /* ecryptfs_do_create() calls ecryptfs_interpose() */
223 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
224 if (unlikely(rc)) {
225 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
226 "lower filesystem\n");
227 goto out;
228 }
229 /* At this point, a file exists on "disk"; we need to make sure
230 * that this on disk file is prepared to be an ecryptfs file */
231 rc = ecryptfs_initialize_file(ecryptfs_dentry);
232 out:
233 return rc;
234 }
235
236 /**
237 * ecryptfs_lookup_and_interpose_lower - Perform a lookup
238 */
239 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
240 struct dentry *lower_dentry,
241 struct inode *ecryptfs_dir_inode,
242 struct nameidata *ecryptfs_nd)
243 {
244 struct dentry *lower_dir_dentry;
245 struct vfsmount *lower_mnt;
246 struct inode *lower_inode;
247 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
248 struct ecryptfs_crypt_stat *crypt_stat;
249 char *page_virt = NULL;
250 u64 file_size;
251 int rc = 0;
252
253 lower_dir_dentry = lower_dentry->d_parent;
254 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
255 ecryptfs_dentry->d_parent));
256 lower_inode = lower_dentry->d_inode;
257 fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
258 BUG_ON(!atomic_read(&lower_dentry->d_count));
259 ecryptfs_set_dentry_private(ecryptfs_dentry,
260 kmem_cache_alloc(ecryptfs_dentry_info_cache,
261 GFP_KERNEL));
262 if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
263 rc = -ENOMEM;
264 printk(KERN_ERR "%s: Out of memory whilst attempting "
265 "to allocate ecryptfs_dentry_info struct\n",
266 __func__);
267 goto out_dput;
268 }
269 ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
270 ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
271 if (!lower_dentry->d_inode) {
272 /* We want to add because we couldn't find in lower */
273 d_add(ecryptfs_dentry, NULL);
274 goto out;
275 }
276 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
277 ecryptfs_dir_inode->i_sb,
278 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
279 if (rc) {
280 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
281 __func__, rc);
282 goto out;
283 }
284 if (S_ISDIR(lower_inode->i_mode))
285 goto out;
286 if (S_ISLNK(lower_inode->i_mode))
287 goto out;
288 if (special_file(lower_inode->i_mode))
289 goto out;
290 if (!ecryptfs_nd)
291 goto out;
292 /* Released in this function */
293 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
294 if (!page_virt) {
295 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
296 __func__);
297 rc = -ENOMEM;
298 goto out;
299 }
300 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
301 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
302 if (rc) {
303 printk(KERN_ERR "%s: Error attempting to initialize "
304 "the persistent file for the dentry with name "
305 "[%s]; rc = [%d]\n", __func__,
306 ecryptfs_dentry->d_name.name, rc);
307 goto out_free_kmem;
308 }
309 }
310 crypt_stat = &ecryptfs_inode_to_private(
311 ecryptfs_dentry->d_inode)->crypt_stat;
312 /* TODO: lock for crypt_stat comparison */
313 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
314 ecryptfs_set_default_sizes(crypt_stat);
315 rc = ecryptfs_read_and_validate_header_region(page_virt,
316 ecryptfs_dentry->d_inode);
317 if (rc) {
318 memset(page_virt, 0, PAGE_CACHE_SIZE);
319 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
320 ecryptfs_dentry);
321 if (rc) {
322 rc = 0;
323 goto out_free_kmem;
324 }
325 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
326 }
327 mount_crypt_stat = &ecryptfs_superblock_to_private(
328 ecryptfs_dentry->d_sb)->mount_crypt_stat;
329 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
330 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
331 file_size = (crypt_stat->metadata_size
332 + i_size_read(lower_dentry->d_inode));
333 else
334 file_size = i_size_read(lower_dentry->d_inode);
335 } else {
336 file_size = get_unaligned_be64(page_virt);
337 }
338 i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
339 out_free_kmem:
340 kmem_cache_free(ecryptfs_header_cache_2, page_virt);
341 goto out;
342 out_dput:
343 dput(lower_dentry);
344 d_drop(ecryptfs_dentry);
345 out:
346 return rc;
347 }
348
349 /**
350 * ecryptfs_lookup
351 * @ecryptfs_dir_inode: The eCryptfs directory inode
352 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
353 * @ecryptfs_nd: nameidata; may be NULL
354 *
355 * Find a file on disk. If the file does not exist, then we'll add it to the
356 * dentry cache and continue on to read it from the disk.
357 */
358 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
359 struct dentry *ecryptfs_dentry,
360 struct nameidata *ecryptfs_nd)
361 {
362 char *encrypted_and_encoded_name = NULL;
363 size_t encrypted_and_encoded_name_size;
364 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
365 struct dentry *lower_dir_dentry, *lower_dentry;
366 int rc = 0;
367
368 ecryptfs_dentry->d_op = &ecryptfs_dops;
369 if ((ecryptfs_dentry->d_name.len == 1
370 && !strcmp(ecryptfs_dentry->d_name.name, "."))
371 || (ecryptfs_dentry->d_name.len == 2
372 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
373 goto out_d_drop;
374 }
375 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
376 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
377 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
378 lower_dir_dentry,
379 ecryptfs_dentry->d_name.len);
380 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
381 if (IS_ERR(lower_dentry)) {
382 rc = PTR_ERR(lower_dentry);
383 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
384 "[%d] on lower_dentry = [%s]\n", __func__, rc,
385 encrypted_and_encoded_name);
386 goto out_d_drop;
387 }
388 if (lower_dentry->d_inode)
389 goto lookup_and_interpose;
390 mount_crypt_stat = &ecryptfs_superblock_to_private(
391 ecryptfs_dentry->d_sb)->mount_crypt_stat;
392 if (!(mount_crypt_stat
393 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
394 goto lookup_and_interpose;
395 dput(lower_dentry);
396 rc = ecryptfs_encrypt_and_encode_filename(
397 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
398 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
399 ecryptfs_dentry->d_name.len);
400 if (rc) {
401 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
402 "filename; rc = [%d]\n", __func__, rc);
403 goto out_d_drop;
404 }
405 mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
406 lower_dentry = lookup_one_len(encrypted_and_encoded_name,
407 lower_dir_dentry,
408 encrypted_and_encoded_name_size - 1);
409 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
410 if (IS_ERR(lower_dentry)) {
411 rc = PTR_ERR(lower_dentry);
412 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
413 "[%d] on lower_dentry = [%s]\n", __func__, rc,
414 encrypted_and_encoded_name);
415 goto out_d_drop;
416 }
417 lookup_and_interpose:
418 rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
419 ecryptfs_dir_inode,
420 ecryptfs_nd);
421 goto out;
422 out_d_drop:
423 d_drop(ecryptfs_dentry);
424 out:
425 kfree(encrypted_and_encoded_name);
426 return ERR_PTR(rc);
427 }
428
429 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
430 struct dentry *new_dentry)
431 {
432 struct dentry *lower_old_dentry;
433 struct dentry *lower_new_dentry;
434 struct dentry *lower_dir_dentry;
435 u64 file_size_save;
436 int rc;
437
438 file_size_save = i_size_read(old_dentry->d_inode);
439 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
440 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
441 dget(lower_old_dentry);
442 dget(lower_new_dentry);
443 lower_dir_dentry = lock_parent(lower_new_dentry);
444 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
445 lower_new_dentry);
446 if (rc || !lower_new_dentry->d_inode)
447 goto out_lock;
448 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
449 if (rc)
450 goto out_lock;
451 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
452 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
453 old_dentry->d_inode->i_nlink =
454 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
455 i_size_write(new_dentry->d_inode, file_size_save);
456 out_lock:
457 unlock_dir(lower_dir_dentry);
458 dput(lower_new_dentry);
459 dput(lower_old_dentry);
460 return rc;
461 }
462
463 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
464 {
465 int rc = 0;
466 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
467 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
468 struct dentry *lower_dir_dentry;
469
470 dget(lower_dentry);
471 lower_dir_dentry = lock_parent(lower_dentry);
472 rc = vfs_unlink(lower_dir_inode, lower_dentry);
473 if (rc) {
474 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
475 goto out_unlock;
476 }
477 fsstack_copy_attr_times(dir, lower_dir_inode);
478 dentry->d_inode->i_nlink =
479 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
480 dentry->d_inode->i_ctime = dir->i_ctime;
481 d_drop(dentry);
482 out_unlock:
483 unlock_dir(lower_dir_dentry);
484 dput(lower_dentry);
485 return rc;
486 }
487
488 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
489 const char *symname)
490 {
491 int rc;
492 struct dentry *lower_dentry;
493 struct dentry *lower_dir_dentry;
494 char *encoded_symname;
495 size_t encoded_symlen;
496 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
497
498 lower_dentry = ecryptfs_dentry_to_lower(dentry);
499 dget(lower_dentry);
500 lower_dir_dentry = lock_parent(lower_dentry);
501 mount_crypt_stat = &ecryptfs_superblock_to_private(
502 dir->i_sb)->mount_crypt_stat;
503 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
504 &encoded_symlen,
505 NULL,
506 mount_crypt_stat, symname,
507 strlen(symname));
508 if (rc)
509 goto out_lock;
510 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
511 encoded_symname);
512 kfree(encoded_symname);
513 if (rc || !lower_dentry->d_inode)
514 goto out_lock;
515 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
516 if (rc)
517 goto out_lock;
518 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
519 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
520 out_lock:
521 unlock_dir(lower_dir_dentry);
522 dput(lower_dentry);
523 if (!dentry->d_inode)
524 d_drop(dentry);
525 return rc;
526 }
527
528 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
529 {
530 int rc;
531 struct dentry *lower_dentry;
532 struct dentry *lower_dir_dentry;
533
534 lower_dentry = ecryptfs_dentry_to_lower(dentry);
535 lower_dir_dentry = lock_parent(lower_dentry);
536 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
537 if (rc || !lower_dentry->d_inode)
538 goto out;
539 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
540 if (rc)
541 goto out;
542 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
543 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
544 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
545 out:
546 unlock_dir(lower_dir_dentry);
547 if (!dentry->d_inode)
548 d_drop(dentry);
549 return rc;
550 }
551
552 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
553 {
554 struct dentry *lower_dentry;
555 struct dentry *lower_dir_dentry;
556 int rc;
557
558 lower_dentry = ecryptfs_dentry_to_lower(dentry);
559 dget(dentry);
560 lower_dir_dentry = lock_parent(lower_dentry);
561 dget(lower_dentry);
562 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
563 dput(lower_dentry);
564 if (!rc)
565 d_delete(lower_dentry);
566 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
567 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
568 unlock_dir(lower_dir_dentry);
569 if (!rc)
570 d_drop(dentry);
571 dput(dentry);
572 return rc;
573 }
574
575 static int
576 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
577 {
578 int rc;
579 struct dentry *lower_dentry;
580 struct dentry *lower_dir_dentry;
581
582 lower_dentry = ecryptfs_dentry_to_lower(dentry);
583 lower_dir_dentry = lock_parent(lower_dentry);
584 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
585 if (rc || !lower_dentry->d_inode)
586 goto out;
587 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
588 if (rc)
589 goto out;
590 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
591 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
592 out:
593 unlock_dir(lower_dir_dentry);
594 if (!dentry->d_inode)
595 d_drop(dentry);
596 return rc;
597 }
598
599 static int
600 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
601 struct inode *new_dir, struct dentry *new_dentry)
602 {
603 int rc;
604 struct dentry *lower_old_dentry;
605 struct dentry *lower_new_dentry;
606 struct dentry *lower_old_dir_dentry;
607 struct dentry *lower_new_dir_dentry;
608 struct dentry *trap = NULL;
609
610 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
611 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
612 dget(lower_old_dentry);
613 dget(lower_new_dentry);
614 lower_old_dir_dentry = dget_parent(lower_old_dentry);
615 lower_new_dir_dentry = dget_parent(lower_new_dentry);
616 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
617 /* source should not be ancestor of target */
618 if (trap == lower_old_dentry) {
619 rc = -EINVAL;
620 goto out_lock;
621 }
622 /* target should not be ancestor of source */
623 if (trap == lower_new_dentry) {
624 rc = -ENOTEMPTY;
625 goto out_lock;
626 }
627 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
628 lower_new_dir_dentry->d_inode, lower_new_dentry);
629 if (rc)
630 goto out_lock;
631 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
632 if (new_dir != old_dir)
633 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
634 out_lock:
635 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
636 dput(lower_new_dentry->d_parent);
637 dput(lower_old_dentry->d_parent);
638 dput(lower_new_dentry);
639 dput(lower_old_dentry);
640 return rc;
641 }
642
643 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
644 size_t *bufsiz)
645 {
646 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
647 char *lower_buf;
648 size_t lower_bufsiz = PATH_MAX;
649 mm_segment_t old_fs;
650 int rc;
651
652 lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
653 if (!lower_buf) {
654 rc = -ENOMEM;
655 goto out;
656 }
657 old_fs = get_fs();
658 set_fs(get_ds());
659 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
660 (char __user *)lower_buf,
661 lower_bufsiz);
662 set_fs(old_fs);
663 if (rc < 0)
664 goto out;
665 lower_bufsiz = rc;
666 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
667 lower_buf, lower_bufsiz);
668 out:
669 kfree(lower_buf);
670 return rc;
671 }
672
673 static int
674 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
675 {
676 char *kbuf;
677 size_t kbufsiz, copied;
678 int rc;
679
680 rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
681 if (rc)
682 goto out;
683 copied = min_t(size_t, bufsiz, kbufsiz);
684 rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
685 kfree(kbuf);
686 fsstack_copy_attr_atime(dentry->d_inode,
687 ecryptfs_dentry_to_lower(dentry)->d_inode);
688 out:
689 return rc;
690 }
691
692 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
693 {
694 char *buf;
695 int len = PAGE_SIZE, rc;
696 mm_segment_t old_fs;
697
698 /* Released in ecryptfs_put_link(); only release here on error */
699 buf = kmalloc(len, GFP_KERNEL);
700 if (!buf) {
701 buf = ERR_PTR(-ENOMEM);
702 goto out;
703 }
704 old_fs = get_fs();
705 set_fs(get_ds());
706 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
707 set_fs(old_fs);
708 if (rc < 0) {
709 kfree(buf);
710 buf = ERR_PTR(rc);
711 } else
712 buf[rc] = '\0';
713 out:
714 nd_set_link(nd, buf);
715 return NULL;
716 }
717
718 static void
719 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
720 {
721 char *buf = nd_get_link(nd);
722 if (!IS_ERR(buf)) {
723 /* Free the char* */
724 kfree(buf);
725 }
726 }
727
728 /**
729 * upper_size_to_lower_size
730 * @crypt_stat: Crypt_stat associated with file
731 * @upper_size: Size of the upper file
732 *
733 * Calculate the required size of the lower file based on the
734 * specified size of the upper file. This calculation is based on the
735 * number of headers in the underlying file and the extent size.
736 *
737 * Returns Calculated size of the lower file.
738 */
739 static loff_t
740 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
741 loff_t upper_size)
742 {
743 loff_t lower_size;
744
745 lower_size = ecryptfs_lower_header_size(crypt_stat);
746 if (upper_size != 0) {
747 loff_t num_extents;
748
749 num_extents = upper_size >> crypt_stat->extent_shift;
750 if (upper_size & ~crypt_stat->extent_mask)
751 num_extents++;
752 lower_size += (num_extents * crypt_stat->extent_size);
753 }
754 return lower_size;
755 }
756
757 /**
758 * truncate_upper
759 * @dentry: The ecryptfs layer dentry
760 * @ia: Address of the ecryptfs inode's attributes
761 * @lower_ia: Address of the lower inode's attributes
762 *
763 * Function to handle truncations modifying the size of the file. Note
764 * that the file sizes are interpolated. When expanding, we are simply
765 * writing strings of 0's out. When truncating, we truncate the upper
766 * inode and update the lower_ia according to the page index
767 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
768 * the caller must use lower_ia in a call to notify_change() to perform
769 * the truncation of the lower inode.
770 *
771 * Returns zero on success; non-zero otherwise
772 */
773 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
774 struct iattr *lower_ia)
775 {
776 int rc = 0;
777 struct inode *inode = dentry->d_inode;
778 struct ecryptfs_crypt_stat *crypt_stat;
779 loff_t i_size = i_size_read(inode);
780 loff_t lower_size_before_truncate;
781 loff_t lower_size_after_truncate;
782
783 if (unlikely((ia->ia_size == i_size))) {
784 lower_ia->ia_valid &= ~ATTR_SIZE;
785 goto out;
786 }
787 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
788 /* Switch on growing or shrinking file */
789 if (ia->ia_size > i_size) {
790 char zero[] = { 0x00 };
791
792 lower_ia->ia_valid &= ~ATTR_SIZE;
793 /* Write a single 0 at the last position of the file;
794 * this triggers code that will fill in 0's throughout
795 * the intermediate portion of the previous end of the
796 * file and the new and of the file */
797 rc = ecryptfs_write(inode, zero,
798 (ia->ia_size - 1), 1);
799 } else { /* ia->ia_size < i_size_read(inode) */
800 /* We're chopping off all the pages down to the page
801 * in which ia->ia_size is located. Fill in the end of
802 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
803 * PAGE_CACHE_SIZE with zeros. */
804 size_t num_zeros = (PAGE_CACHE_SIZE
805 - (ia->ia_size & ~PAGE_CACHE_MASK));
806
807
808 /*
809 * XXX(truncate) this should really happen at the begginning
810 * of ->setattr. But the code is too messy to that as part
811 * of a larger patch. ecryptfs is also totally missing out
812 * on the inode_change_ok check at the beginning of
813 * ->setattr while would include this.
814 */
815 rc = inode_newsize_ok(inode, ia->ia_size);
816 if (rc)
817 goto out;
818
819 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
820 truncate_setsize(inode, ia->ia_size);
821 lower_ia->ia_size = ia->ia_size;
822 lower_ia->ia_valid |= ATTR_SIZE;
823 goto out;
824 }
825 if (num_zeros) {
826 char *zeros_virt;
827
828 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
829 if (!zeros_virt) {
830 rc = -ENOMEM;
831 goto out;
832 }
833 rc = ecryptfs_write(inode, zeros_virt,
834 ia->ia_size, num_zeros);
835 kfree(zeros_virt);
836 if (rc) {
837 printk(KERN_ERR "Error attempting to zero out "
838 "the remainder of the end page on "
839 "reducing truncate; rc = [%d]\n", rc);
840 goto out;
841 }
842 }
843 truncate_setsize(inode, ia->ia_size);
844 rc = ecryptfs_write_inode_size_to_metadata(inode);
845 if (rc) {
846 printk(KERN_ERR "Problem with "
847 "ecryptfs_write_inode_size_to_metadata; "
848 "rc = [%d]\n", rc);
849 goto out;
850 }
851 /* We are reducing the size of the ecryptfs file, and need to
852 * know if we need to reduce the size of the lower file. */
853 lower_size_before_truncate =
854 upper_size_to_lower_size(crypt_stat, i_size);
855 lower_size_after_truncate =
856 upper_size_to_lower_size(crypt_stat, ia->ia_size);
857 if (lower_size_after_truncate < lower_size_before_truncate) {
858 lower_ia->ia_size = lower_size_after_truncate;
859 lower_ia->ia_valid |= ATTR_SIZE;
860 } else
861 lower_ia->ia_valid &= ~ATTR_SIZE;
862 }
863 out:
864 return rc;
865 }
866
867 /**
868 * ecryptfs_truncate
869 * @dentry: The ecryptfs layer dentry
870 * @new_length: The length to expand the file to
871 *
872 * Simple function that handles the truncation of an eCryptfs inode and
873 * its corresponding lower inode.
874 *
875 * Returns zero on success; non-zero otherwise
876 */
877 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
878 {
879 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
880 struct iattr lower_ia = { .ia_valid = 0 };
881 int rc;
882
883 rc = truncate_upper(dentry, &ia, &lower_ia);
884 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
885 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
886
887 mutex_lock(&lower_dentry->d_inode->i_mutex);
888 rc = notify_change(lower_dentry, &lower_ia);
889 mutex_unlock(&lower_dentry->d_inode->i_mutex);
890 }
891 return rc;
892 }
893
894 static int
895 ecryptfs_permission(struct inode *inode, int mask)
896 {
897 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
898 }
899
900 /**
901 * ecryptfs_setattr
902 * @dentry: dentry handle to the inode to modify
903 * @ia: Structure with flags of what to change and values
904 *
905 * Updates the metadata of an inode. If the update is to the size
906 * i.e. truncation, then ecryptfs_truncate will handle the size modification
907 * of both the ecryptfs inode and the lower inode.
908 *
909 * All other metadata changes will be passed right to the lower filesystem,
910 * and we will just update our inode to look like the lower.
911 */
912 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
913 {
914 int rc = 0;
915 struct dentry *lower_dentry;
916 struct iattr lower_ia;
917 struct inode *inode;
918 struct inode *lower_inode;
919 struct ecryptfs_crypt_stat *crypt_stat;
920
921 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
922 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
923 ecryptfs_init_crypt_stat(crypt_stat);
924 inode = dentry->d_inode;
925 lower_inode = ecryptfs_inode_to_lower(inode);
926 lower_dentry = ecryptfs_dentry_to_lower(dentry);
927 mutex_lock(&crypt_stat->cs_mutex);
928 if (S_ISDIR(dentry->d_inode->i_mode))
929 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
930 else if (S_ISREG(dentry->d_inode->i_mode)
931 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
932 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
933 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
934
935 mount_crypt_stat = &ecryptfs_superblock_to_private(
936 dentry->d_sb)->mount_crypt_stat;
937 rc = ecryptfs_read_metadata(dentry);
938 if (rc) {
939 if (!(mount_crypt_stat->flags
940 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
941 rc = -EIO;
942 printk(KERN_WARNING "Either the lower file "
943 "is not in a valid eCryptfs format, "
944 "or the key could not be retrieved. "
945 "Plaintext passthrough mode is not "
946 "enabled; returning -EIO\n");
947 mutex_unlock(&crypt_stat->cs_mutex);
948 goto out;
949 }
950 rc = 0;
951 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
952 }
953 }
954 mutex_unlock(&crypt_stat->cs_mutex);
955 memcpy(&lower_ia, ia, sizeof(lower_ia));
956 if (ia->ia_valid & ATTR_FILE)
957 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
958 if (ia->ia_valid & ATTR_SIZE) {
959 rc = truncate_upper(dentry, ia, &lower_ia);
960 if (rc < 0)
961 goto out;
962 }
963
964 /*
965 * mode change is for clearing setuid/setgid bits. Allow lower fs
966 * to interpret this in its own way.
967 */
968 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
969 lower_ia.ia_valid &= ~ATTR_MODE;
970
971 mutex_lock(&lower_dentry->d_inode->i_mutex);
972 rc = notify_change(lower_dentry, &lower_ia);
973 mutex_unlock(&lower_dentry->d_inode->i_mutex);
974 out:
975 fsstack_copy_attr_all(inode, lower_inode);
976 return rc;
977 }
978
979 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
980 struct kstat *stat)
981 {
982 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
983 int rc = 0;
984
985 mount_crypt_stat = &ecryptfs_superblock_to_private(
986 dentry->d_sb)->mount_crypt_stat;
987 generic_fillattr(dentry->d_inode, stat);
988 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
989 char *target;
990 size_t targetsiz;
991
992 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
993 if (!rc) {
994 kfree(target);
995 stat->size = targetsiz;
996 }
997 }
998 return rc;
999 }
1000
1001 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1002 struct kstat *stat)
1003 {
1004 struct kstat lower_stat;
1005 int rc;
1006
1007 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1008 ecryptfs_dentry_to_lower(dentry), &lower_stat);
1009 if (!rc) {
1010 generic_fillattr(dentry->d_inode, stat);
1011 stat->blocks = lower_stat.blocks;
1012 }
1013 return rc;
1014 }
1015
1016 int
1017 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1018 size_t size, int flags)
1019 {
1020 int rc = 0;
1021 struct dentry *lower_dentry;
1022
1023 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1024 if (!lower_dentry->d_inode->i_op->setxattr) {
1025 rc = -EOPNOTSUPP;
1026 goto out;
1027 }
1028 mutex_lock(&lower_dentry->d_inode->i_mutex);
1029 rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
1030 size, flags);
1031 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1032 out:
1033 return rc;
1034 }
1035
1036 ssize_t
1037 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1038 void *value, size_t size)
1039 {
1040 int rc = 0;
1041
1042 if (!lower_dentry->d_inode->i_op->getxattr) {
1043 rc = -EOPNOTSUPP;
1044 goto out;
1045 }
1046 mutex_lock(&lower_dentry->d_inode->i_mutex);
1047 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1048 size);
1049 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1050 out:
1051 return rc;
1052 }
1053
1054 static ssize_t
1055 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1056 size_t size)
1057 {
1058 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1059 value, size);
1060 }
1061
1062 static ssize_t
1063 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1064 {
1065 int rc = 0;
1066 struct dentry *lower_dentry;
1067
1068 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1069 if (!lower_dentry->d_inode->i_op->listxattr) {
1070 rc = -EOPNOTSUPP;
1071 goto out;
1072 }
1073 mutex_lock(&lower_dentry->d_inode->i_mutex);
1074 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1075 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1076 out:
1077 return rc;
1078 }
1079
1080 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1081 {
1082 int rc = 0;
1083 struct dentry *lower_dentry;
1084
1085 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1086 if (!lower_dentry->d_inode->i_op->removexattr) {
1087 rc = -EOPNOTSUPP;
1088 goto out;
1089 }
1090 mutex_lock(&lower_dentry->d_inode->i_mutex);
1091 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1092 mutex_unlock(&lower_dentry->d_inode->i_mutex);
1093 out:
1094 return rc;
1095 }
1096
1097 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1098 {
1099 if ((ecryptfs_inode_to_lower(inode)
1100 == (struct inode *)candidate_lower_inode))
1101 return 1;
1102 else
1103 return 0;
1104 }
1105
1106 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1107 {
1108 ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1109 return 0;
1110 }
1111
1112 const struct inode_operations ecryptfs_symlink_iops = {
1113 .readlink = ecryptfs_readlink,
1114 .follow_link = ecryptfs_follow_link,
1115 .put_link = ecryptfs_put_link,
1116 .permission = ecryptfs_permission,
1117 .setattr = ecryptfs_setattr,
1118 .getattr = ecryptfs_getattr_link,
1119 .setxattr = ecryptfs_setxattr,
1120 .getxattr = ecryptfs_getxattr,
1121 .listxattr = ecryptfs_listxattr,
1122 .removexattr = ecryptfs_removexattr
1123 };
1124
1125 const struct inode_operations ecryptfs_dir_iops = {
1126 .create = ecryptfs_create,
1127 .lookup = ecryptfs_lookup,
1128 .link = ecryptfs_link,
1129 .unlink = ecryptfs_unlink,
1130 .symlink = ecryptfs_symlink,
1131 .mkdir = ecryptfs_mkdir,
1132 .rmdir = ecryptfs_rmdir,
1133 .mknod = ecryptfs_mknod,
1134 .rename = ecryptfs_rename,
1135 .permission = ecryptfs_permission,
1136 .setattr = ecryptfs_setattr,
1137 .setxattr = ecryptfs_setxattr,
1138 .getxattr = ecryptfs_getxattr,
1139 .listxattr = ecryptfs_listxattr,
1140 .removexattr = ecryptfs_removexattr
1141 };
1142
1143 const struct inode_operations ecryptfs_main_iops = {
1144 .permission = ecryptfs_permission,
1145 .setattr = ecryptfs_setattr,
1146 .getattr = ecryptfs_getattr,
1147 .setxattr = ecryptfs_setxattr,
1148 .getxattr = ecryptfs_getxattr,
1149 .listxattr = ecryptfs_listxattr,
1150 .removexattr = ecryptfs_removexattr
1151 };