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