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