]> Pileus Git - ~andy/linux/blob - fs/ecryptfs/inode.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
[~andy/linux] / 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_crypt_stat *crypt_stat;
229         char *page_virt = NULL;
230         int put_lower = 0, rc = 0;
231
232         lower_dir_dentry = lower_dentry->d_parent;
233         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
234                                    ecryptfs_dentry->d_parent));
235         lower_inode = lower_dentry->d_inode;
236         fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
237         BUG_ON(!lower_dentry->d_count);
238         ecryptfs_set_dentry_private(ecryptfs_dentry,
239                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
240                                                      GFP_KERNEL));
241         if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
242                 rc = -ENOMEM;
243                 printk(KERN_ERR "%s: Out of memory whilst attempting "
244                        "to allocate ecryptfs_dentry_info struct\n",
245                         __func__);
246                 goto out_put;
247         }
248         ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
249         ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
250         if (!lower_dentry->d_inode) {
251                 /* We want to add because we couldn't find in lower */
252                 d_add(ecryptfs_dentry, NULL);
253                 goto out;
254         }
255         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
256                                 ecryptfs_dir_inode->i_sb,
257                                 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
258         if (rc) {
259                 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
260                        __func__, rc);
261                 goto out;
262         }
263         if (S_ISDIR(lower_inode->i_mode))
264                 goto out;
265         if (S_ISLNK(lower_inode->i_mode))
266                 goto out;
267         if (special_file(lower_inode->i_mode))
268                 goto out;
269         /* Released in this function */
270         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
271         if (!page_virt) {
272                 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
273                        __func__);
274                 rc = -ENOMEM;
275                 goto out;
276         }
277         rc = ecryptfs_get_lower_file(ecryptfs_dentry);
278         if (rc) {
279                 printk(KERN_ERR "%s: Error attempting to initialize "
280                         "the lower file for the dentry with name "
281                         "[%s]; rc = [%d]\n", __func__,
282                         ecryptfs_dentry->d_name.name, rc);
283                 goto out_free_kmem;
284         }
285         put_lower = 1;
286         crypt_stat = &ecryptfs_inode_to_private(
287                                         ecryptfs_dentry->d_inode)->crypt_stat;
288         /* TODO: lock for crypt_stat comparison */
289         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
290                         ecryptfs_set_default_sizes(crypt_stat);
291         rc = ecryptfs_read_and_validate_header_region(page_virt,
292                                                       ecryptfs_dentry->d_inode);
293         if (rc) {
294                 memset(page_virt, 0, PAGE_CACHE_SIZE);
295                 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
296                                                              ecryptfs_dentry);
297                 if (rc) {
298                         rc = 0;
299                         goto out_free_kmem;
300                 }
301                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
302         }
303         ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
304 out_free_kmem:
305         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
306         goto out;
307 out_put:
308         dput(lower_dentry);
309         mntput(lower_mnt);
310         d_drop(ecryptfs_dentry);
311 out:
312         if (put_lower)
313                 ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
314         return rc;
315 }
316
317 /**
318  * ecryptfs_lookup
319  * @ecryptfs_dir_inode: The eCryptfs directory inode
320  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
321  * @ecryptfs_nd: nameidata; may be NULL
322  *
323  * Find a file on disk. If the file does not exist, then we'll add it to the
324  * dentry cache and continue on to read it from the disk.
325  */
326 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
327                                       struct dentry *ecryptfs_dentry,
328                                       struct nameidata *ecryptfs_nd)
329 {
330         char *encrypted_and_encoded_name = NULL;
331         size_t encrypted_and_encoded_name_size;
332         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
333         struct dentry *lower_dir_dentry, *lower_dentry;
334         int rc = 0;
335
336         if ((ecryptfs_dentry->d_name.len == 1
337              && !strcmp(ecryptfs_dentry->d_name.name, "."))
338             || (ecryptfs_dentry->d_name.len == 2
339                 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
340                 goto out_d_drop;
341         }
342         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
343         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
344         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
345                                       lower_dir_dentry,
346                                       ecryptfs_dentry->d_name.len);
347         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
348         if (IS_ERR(lower_dentry)) {
349                 rc = PTR_ERR(lower_dentry);
350                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
351                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
352                                 encrypted_and_encoded_name);
353                 goto out_d_drop;
354         }
355         if (lower_dentry->d_inode)
356                 goto lookup_and_interpose;
357         mount_crypt_stat = &ecryptfs_superblock_to_private(
358                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
359         if (!(mount_crypt_stat
360             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
361                 goto lookup_and_interpose;
362         dput(lower_dentry);
363         rc = ecryptfs_encrypt_and_encode_filename(
364                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
365                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
366                 ecryptfs_dentry->d_name.len);
367         if (rc) {
368                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
369                        "filename; rc = [%d]\n", __func__, rc);
370                 goto out_d_drop;
371         }
372         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
373         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
374                                       lower_dir_dentry,
375                                       encrypted_and_encoded_name_size);
376         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
377         if (IS_ERR(lower_dentry)) {
378                 rc = PTR_ERR(lower_dentry);
379                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
380                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
381                                 encrypted_and_encoded_name);
382                 goto out_d_drop;
383         }
384 lookup_and_interpose:
385         rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
386                                                  ecryptfs_dir_inode);
387         goto out;
388 out_d_drop:
389         d_drop(ecryptfs_dentry);
390 out:
391         kfree(encrypted_and_encoded_name);
392         return ERR_PTR(rc);
393 }
394
395 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
396                          struct dentry *new_dentry)
397 {
398         struct dentry *lower_old_dentry;
399         struct dentry *lower_new_dentry;
400         struct dentry *lower_dir_dentry;
401         u64 file_size_save;
402         int rc;
403
404         file_size_save = i_size_read(old_dentry->d_inode);
405         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
406         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
407         dget(lower_old_dentry);
408         dget(lower_new_dentry);
409         lower_dir_dentry = lock_parent(lower_new_dentry);
410         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
411                       lower_new_dentry);
412         if (rc || !lower_new_dentry->d_inode)
413                 goto out_lock;
414         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
415         if (rc)
416                 goto out_lock;
417         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
418         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
419         old_dentry->d_inode->i_nlink =
420                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
421         i_size_write(new_dentry->d_inode, file_size_save);
422 out_lock:
423         unlock_dir(lower_dir_dentry);
424         dput(lower_new_dentry);
425         dput(lower_old_dentry);
426         return rc;
427 }
428
429 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
430 {
431         int rc = 0;
432         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
433         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
434         struct dentry *lower_dir_dentry;
435
436         dget(lower_dentry);
437         lower_dir_dentry = lock_parent(lower_dentry);
438         rc = vfs_unlink(lower_dir_inode, lower_dentry);
439         if (rc) {
440                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
441                 goto out_unlock;
442         }
443         fsstack_copy_attr_times(dir, lower_dir_inode);
444         dentry->d_inode->i_nlink =
445                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
446         dentry->d_inode->i_ctime = dir->i_ctime;
447         d_drop(dentry);
448 out_unlock:
449         unlock_dir(lower_dir_dentry);
450         dput(lower_dentry);
451         return rc;
452 }
453
454 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
455                             const char *symname)
456 {
457         int rc;
458         struct dentry *lower_dentry;
459         struct dentry *lower_dir_dentry;
460         char *encoded_symname;
461         size_t encoded_symlen;
462         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
463
464         lower_dentry = ecryptfs_dentry_to_lower(dentry);
465         dget(lower_dentry);
466         lower_dir_dentry = lock_parent(lower_dentry);
467         mount_crypt_stat = &ecryptfs_superblock_to_private(
468                 dir->i_sb)->mount_crypt_stat;
469         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
470                                                   &encoded_symlen,
471                                                   NULL,
472                                                   mount_crypt_stat, symname,
473                                                   strlen(symname));
474         if (rc)
475                 goto out_lock;
476         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
477                          encoded_symname);
478         kfree(encoded_symname);
479         if (rc || !lower_dentry->d_inode)
480                 goto out_lock;
481         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
482         if (rc)
483                 goto out_lock;
484         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
485         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
486 out_lock:
487         unlock_dir(lower_dir_dentry);
488         dput(lower_dentry);
489         if (!dentry->d_inode)
490                 d_drop(dentry);
491         return rc;
492 }
493
494 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
495 {
496         int rc;
497         struct dentry *lower_dentry;
498         struct dentry *lower_dir_dentry;
499
500         lower_dentry = ecryptfs_dentry_to_lower(dentry);
501         lower_dir_dentry = lock_parent(lower_dentry);
502         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
503         if (rc || !lower_dentry->d_inode)
504                 goto out;
505         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
506         if (rc)
507                 goto out;
508         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
509         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
510         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
511 out:
512         unlock_dir(lower_dir_dentry);
513         if (!dentry->d_inode)
514                 d_drop(dentry);
515         return rc;
516 }
517
518 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
519 {
520         struct dentry *lower_dentry;
521         struct dentry *lower_dir_dentry;
522         int rc;
523
524         lower_dentry = ecryptfs_dentry_to_lower(dentry);
525         dget(dentry);
526         lower_dir_dentry = lock_parent(lower_dentry);
527         dget(lower_dentry);
528         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
529         dput(lower_dentry);
530         if (!rc && dentry->d_inode)
531                 clear_nlink(dentry->d_inode);
532         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
533         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
534         unlock_dir(lower_dir_dentry);
535         if (!rc)
536                 d_drop(dentry);
537         dput(dentry);
538         return rc;
539 }
540
541 static int
542 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
543 {
544         int rc;
545         struct dentry *lower_dentry;
546         struct dentry *lower_dir_dentry;
547
548         lower_dentry = ecryptfs_dentry_to_lower(dentry);
549         lower_dir_dentry = lock_parent(lower_dentry);
550         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
551         if (rc || !lower_dentry->d_inode)
552                 goto out;
553         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
554         if (rc)
555                 goto out;
556         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
557         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
558 out:
559         unlock_dir(lower_dir_dentry);
560         if (!dentry->d_inode)
561                 d_drop(dentry);
562         return rc;
563 }
564
565 static int
566 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
567                 struct inode *new_dir, struct dentry *new_dentry)
568 {
569         int rc;
570         struct dentry *lower_old_dentry;
571         struct dentry *lower_new_dentry;
572         struct dentry *lower_old_dir_dentry;
573         struct dentry *lower_new_dir_dentry;
574         struct dentry *trap = NULL;
575
576         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
577         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
578         dget(lower_old_dentry);
579         dget(lower_new_dentry);
580         lower_old_dir_dentry = dget_parent(lower_old_dentry);
581         lower_new_dir_dentry = dget_parent(lower_new_dentry);
582         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
583         /* source should not be ancestor of target */
584         if (trap == lower_old_dentry) {
585                 rc = -EINVAL;
586                 goto out_lock;
587         }
588         /* target should not be ancestor of source */
589         if (trap == lower_new_dentry) {
590                 rc = -ENOTEMPTY;
591                 goto out_lock;
592         }
593         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
594                         lower_new_dir_dentry->d_inode, lower_new_dentry);
595         if (rc)
596                 goto out_lock;
597         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
598         if (new_dir != old_dir)
599                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
600 out_lock:
601         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
602         dput(lower_new_dir_dentry);
603         dput(lower_old_dir_dentry);
604         dput(lower_new_dentry);
605         dput(lower_old_dentry);
606         return rc;
607 }
608
609 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
610                                    size_t *bufsiz)
611 {
612         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
613         char *lower_buf;
614         size_t lower_bufsiz = PATH_MAX;
615         mm_segment_t old_fs;
616         int rc;
617
618         lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
619         if (!lower_buf) {
620                 rc = -ENOMEM;
621                 goto out;
622         }
623         old_fs = get_fs();
624         set_fs(get_ds());
625         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
626                                                    (char __user *)lower_buf,
627                                                    lower_bufsiz);
628         set_fs(old_fs);
629         if (rc < 0)
630                 goto out;
631         lower_bufsiz = rc;
632         rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
633                                                   lower_buf, lower_bufsiz);
634 out:
635         kfree(lower_buf);
636         return rc;
637 }
638
639 static int
640 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
641 {
642         char *kbuf;
643         size_t kbufsiz, copied;
644         int rc;
645
646         rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
647         if (rc)
648                 goto out;
649         copied = min_t(size_t, bufsiz, kbufsiz);
650         rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
651         kfree(kbuf);
652         fsstack_copy_attr_atime(dentry->d_inode,
653                                 ecryptfs_dentry_to_lower(dentry)->d_inode);
654 out:
655         return rc;
656 }
657
658 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
659 {
660         char *buf;
661         int len = PAGE_SIZE, rc;
662         mm_segment_t old_fs;
663
664         /* Released in ecryptfs_put_link(); only release here on error */
665         buf = kmalloc(len, GFP_KERNEL);
666         if (!buf) {
667                 buf = ERR_PTR(-ENOMEM);
668                 goto out;
669         }
670         old_fs = get_fs();
671         set_fs(get_ds());
672         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
673         set_fs(old_fs);
674         if (rc < 0) {
675                 kfree(buf);
676                 buf = ERR_PTR(rc);
677         } else
678                 buf[rc] = '\0';
679 out:
680         nd_set_link(nd, buf);
681         return NULL;
682 }
683
684 static void
685 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
686 {
687         char *buf = nd_get_link(nd);
688         if (!IS_ERR(buf)) {
689                 /* Free the char* */
690                 kfree(buf);
691         }
692 }
693
694 /**
695  * upper_size_to_lower_size
696  * @crypt_stat: Crypt_stat associated with file
697  * @upper_size: Size of the upper file
698  *
699  * Calculate the required size of the lower file based on the
700  * specified size of the upper file. This calculation is based on the
701  * number of headers in the underlying file and the extent size.
702  *
703  * Returns Calculated size of the lower file.
704  */
705 static loff_t
706 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
707                          loff_t upper_size)
708 {
709         loff_t lower_size;
710
711         lower_size = ecryptfs_lower_header_size(crypt_stat);
712         if (upper_size != 0) {
713                 loff_t num_extents;
714
715                 num_extents = upper_size >> crypt_stat->extent_shift;
716                 if (upper_size & ~crypt_stat->extent_mask)
717                         num_extents++;
718                 lower_size += (num_extents * crypt_stat->extent_size);
719         }
720         return lower_size;
721 }
722
723 /**
724  * truncate_upper
725  * @dentry: The ecryptfs layer dentry
726  * @ia: Address of the ecryptfs inode's attributes
727  * @lower_ia: Address of the lower inode's attributes
728  *
729  * Function to handle truncations modifying the size of the file. Note
730  * that the file sizes are interpolated. When expanding, we are simply
731  * writing strings of 0's out. When truncating, we truncate the upper
732  * inode and update the lower_ia according to the page index
733  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
734  * the caller must use lower_ia in a call to notify_change() to perform
735  * the truncation of the lower inode.
736  *
737  * Returns zero on success; non-zero otherwise
738  */
739 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
740                           struct iattr *lower_ia)
741 {
742         int rc = 0;
743         struct inode *inode = dentry->d_inode;
744         struct ecryptfs_crypt_stat *crypt_stat;
745         loff_t i_size = i_size_read(inode);
746         loff_t lower_size_before_truncate;
747         loff_t lower_size_after_truncate;
748
749         if (unlikely((ia->ia_size == i_size))) {
750                 lower_ia->ia_valid &= ~ATTR_SIZE;
751                 return 0;
752         }
753         rc = ecryptfs_get_lower_file(dentry);
754         if (rc)
755                 return rc;
756         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
757         /* Switch on growing or shrinking file */
758         if (ia->ia_size > i_size) {
759                 char zero[] = { 0x00 };
760
761                 lower_ia->ia_valid &= ~ATTR_SIZE;
762                 /* Write a single 0 at the last position of the file;
763                  * this triggers code that will fill in 0's throughout
764                  * the intermediate portion of the previous end of the
765                  * file and the new and of the file */
766                 rc = ecryptfs_write(inode, zero,
767                                     (ia->ia_size - 1), 1);
768         } else { /* ia->ia_size < i_size_read(inode) */
769                 /* We're chopping off all the pages down to the page
770                  * in which ia->ia_size is located. Fill in the end of
771                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
772                  * PAGE_CACHE_SIZE with zeros. */
773                 size_t num_zeros = (PAGE_CACHE_SIZE
774                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
775
776
777                 /*
778                  * XXX(truncate) this should really happen at the begginning
779                  * of ->setattr.  But the code is too messy to that as part
780                  * of a larger patch.  ecryptfs is also totally missing out
781                  * on the inode_change_ok check at the beginning of
782                  * ->setattr while would include this.
783                  */
784                 rc = inode_newsize_ok(inode, ia->ia_size);
785                 if (rc)
786                         goto out;
787
788                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
789                         truncate_setsize(inode, ia->ia_size);
790                         lower_ia->ia_size = ia->ia_size;
791                         lower_ia->ia_valid |= ATTR_SIZE;
792                         goto out;
793                 }
794                 if (num_zeros) {
795                         char *zeros_virt;
796
797                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
798                         if (!zeros_virt) {
799                                 rc = -ENOMEM;
800                                 goto out;
801                         }
802                         rc = ecryptfs_write(inode, zeros_virt,
803                                             ia->ia_size, num_zeros);
804                         kfree(zeros_virt);
805                         if (rc) {
806                                 printk(KERN_ERR "Error attempting to zero out "
807                                        "the remainder of the end page on "
808                                        "reducing truncate; rc = [%d]\n", rc);
809                                 goto out;
810                         }
811                 }
812                 truncate_setsize(inode, ia->ia_size);
813                 rc = ecryptfs_write_inode_size_to_metadata(inode);
814                 if (rc) {
815                         printk(KERN_ERR "Problem with "
816                                "ecryptfs_write_inode_size_to_metadata; "
817                                "rc = [%d]\n", rc);
818                         goto out;
819                 }
820                 /* We are reducing the size of the ecryptfs file, and need to
821                  * know if we need to reduce the size of the lower file. */
822                 lower_size_before_truncate =
823                     upper_size_to_lower_size(crypt_stat, i_size);
824                 lower_size_after_truncate =
825                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
826                 if (lower_size_after_truncate < lower_size_before_truncate) {
827                         lower_ia->ia_size = lower_size_after_truncate;
828                         lower_ia->ia_valid |= ATTR_SIZE;
829                 } else
830                         lower_ia->ia_valid &= ~ATTR_SIZE;
831         }
832 out:
833         ecryptfs_put_lower_file(inode);
834         return rc;
835 }
836
837 /**
838  * ecryptfs_truncate
839  * @dentry: The ecryptfs layer dentry
840  * @new_length: The length to expand the file to
841  *
842  * Simple function that handles the truncation of an eCryptfs inode and
843  * its corresponding lower inode.
844  *
845  * Returns zero on success; non-zero otherwise
846  */
847 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
848 {
849         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
850         struct iattr lower_ia = { .ia_valid = 0 };
851         int rc;
852
853         rc = truncate_upper(dentry, &ia, &lower_ia);
854         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
855                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
856
857                 mutex_lock(&lower_dentry->d_inode->i_mutex);
858                 rc = notify_change(lower_dentry, &lower_ia);
859                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
860         }
861         return rc;
862 }
863
864 static int
865 ecryptfs_permission(struct inode *inode, int mask, unsigned int flags)
866 {
867         if (flags & IPERM_FLAG_RCU)
868                 return -ECHILD;
869         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
870 }
871
872 /**
873  * ecryptfs_setattr
874  * @dentry: dentry handle to the inode to modify
875  * @ia: Structure with flags of what to change and values
876  *
877  * Updates the metadata of an inode. If the update is to the size
878  * i.e. truncation, then ecryptfs_truncate will handle the size modification
879  * of both the ecryptfs inode and the lower inode.
880  *
881  * All other metadata changes will be passed right to the lower filesystem,
882  * and we will just update our inode to look like the lower.
883  */
884 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
885 {
886         int rc = 0;
887         struct dentry *lower_dentry;
888         struct iattr lower_ia;
889         struct inode *inode;
890         struct inode *lower_inode;
891         struct ecryptfs_crypt_stat *crypt_stat;
892
893         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
894         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
895                 ecryptfs_init_crypt_stat(crypt_stat);
896         inode = dentry->d_inode;
897         lower_inode = ecryptfs_inode_to_lower(inode);
898         lower_dentry = ecryptfs_dentry_to_lower(dentry);
899         mutex_lock(&crypt_stat->cs_mutex);
900         if (S_ISDIR(dentry->d_inode->i_mode))
901                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
902         else if (S_ISREG(dentry->d_inode->i_mode)
903                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
904                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
905                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
906
907                 mount_crypt_stat = &ecryptfs_superblock_to_private(
908                         dentry->d_sb)->mount_crypt_stat;
909                 rc = ecryptfs_get_lower_file(dentry);
910                 if (rc) {
911                         mutex_unlock(&crypt_stat->cs_mutex);
912                         goto out;
913                 }
914                 rc = ecryptfs_read_metadata(dentry);
915                 ecryptfs_put_lower_file(inode);
916                 if (rc) {
917                         if (!(mount_crypt_stat->flags
918                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
919                                 rc = -EIO;
920                                 printk(KERN_WARNING "Either the lower file "
921                                        "is not in a valid eCryptfs format, "
922                                        "or the key could not be retrieved. "
923                                        "Plaintext passthrough mode is not "
924                                        "enabled; returning -EIO\n");
925                                 mutex_unlock(&crypt_stat->cs_mutex);
926                                 goto out;
927                         }
928                         rc = 0;
929                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
930                                                | ECRYPTFS_ENCRYPTED);
931                 }
932         }
933         mutex_unlock(&crypt_stat->cs_mutex);
934         if (S_ISREG(inode->i_mode)) {
935                 rc = filemap_write_and_wait(inode->i_mapping);
936                 if (rc)
937                         goto out;
938                 fsstack_copy_attr_all(inode, lower_inode);
939         }
940         memcpy(&lower_ia, ia, sizeof(lower_ia));
941         if (ia->ia_valid & ATTR_FILE)
942                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
943         if (ia->ia_valid & ATTR_SIZE) {
944                 rc = truncate_upper(dentry, ia, &lower_ia);
945                 if (rc < 0)
946                         goto out;
947         }
948
949         /*
950          * mode change is for clearing setuid/setgid bits. Allow lower fs
951          * to interpret this in its own way.
952          */
953         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
954                 lower_ia.ia_valid &= ~ATTR_MODE;
955
956         mutex_lock(&lower_dentry->d_inode->i_mutex);
957         rc = notify_change(lower_dentry, &lower_ia);
958         mutex_unlock(&lower_dentry->d_inode->i_mutex);
959 out:
960         fsstack_copy_attr_all(inode, lower_inode);
961         return rc;
962 }
963
964 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
965                           struct kstat *stat)
966 {
967         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
968         int rc = 0;
969
970         mount_crypt_stat = &ecryptfs_superblock_to_private(
971                                                 dentry->d_sb)->mount_crypt_stat;
972         generic_fillattr(dentry->d_inode, stat);
973         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
974                 char *target;
975                 size_t targetsiz;
976
977                 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
978                 if (!rc) {
979                         kfree(target);
980                         stat->size = targetsiz;
981                 }
982         }
983         return rc;
984 }
985
986 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
987                      struct kstat *stat)
988 {
989         struct kstat lower_stat;
990         int rc;
991
992         rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
993                          ecryptfs_dentry_to_lower(dentry), &lower_stat);
994         if (!rc) {
995                 fsstack_copy_attr_all(dentry->d_inode,
996                                       ecryptfs_inode_to_lower(dentry->d_inode));
997                 generic_fillattr(dentry->d_inode, stat);
998                 stat->blocks = lower_stat.blocks;
999         }
1000         return rc;
1001 }
1002
1003 int
1004 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1005                   size_t size, int flags)
1006 {
1007         int rc = 0;
1008         struct dentry *lower_dentry;
1009
1010         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1011         if (!lower_dentry->d_inode->i_op->setxattr) {
1012                 rc = -EOPNOTSUPP;
1013                 goto out;
1014         }
1015
1016         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1017 out:
1018         return rc;
1019 }
1020
1021 ssize_t
1022 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1023                         void *value, size_t size)
1024 {
1025         int rc = 0;
1026
1027         if (!lower_dentry->d_inode->i_op->getxattr) {
1028                 rc = -EOPNOTSUPP;
1029                 goto out;
1030         }
1031         mutex_lock(&lower_dentry->d_inode->i_mutex);
1032         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1033                                                    size);
1034         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1035 out:
1036         return rc;
1037 }
1038
1039 static ssize_t
1040 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1041                   size_t size)
1042 {
1043         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1044                                        value, size);
1045 }
1046
1047 static ssize_t
1048 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1049 {
1050         int rc = 0;
1051         struct dentry *lower_dentry;
1052
1053         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1054         if (!lower_dentry->d_inode->i_op->listxattr) {
1055                 rc = -EOPNOTSUPP;
1056                 goto out;
1057         }
1058         mutex_lock(&lower_dentry->d_inode->i_mutex);
1059         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1060         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1061 out:
1062         return rc;
1063 }
1064
1065 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1066 {
1067         int rc = 0;
1068         struct dentry *lower_dentry;
1069
1070         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1071         if (!lower_dentry->d_inode->i_op->removexattr) {
1072                 rc = -EOPNOTSUPP;
1073                 goto out;
1074         }
1075         mutex_lock(&lower_dentry->d_inode->i_mutex);
1076         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1077         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1078 out:
1079         return rc;
1080 }
1081
1082 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1083 {
1084         if ((ecryptfs_inode_to_lower(inode)
1085              == (struct inode *)candidate_lower_inode))
1086                 return 1;
1087         else
1088                 return 0;
1089 }
1090
1091 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1092 {
1093         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1094         return 0;
1095 }
1096
1097 const struct inode_operations ecryptfs_symlink_iops = {
1098         .readlink = ecryptfs_readlink,
1099         .follow_link = ecryptfs_follow_link,
1100         .put_link = ecryptfs_put_link,
1101         .permission = ecryptfs_permission,
1102         .setattr = ecryptfs_setattr,
1103         .getattr = ecryptfs_getattr_link,
1104         .setxattr = ecryptfs_setxattr,
1105         .getxattr = ecryptfs_getxattr,
1106         .listxattr = ecryptfs_listxattr,
1107         .removexattr = ecryptfs_removexattr
1108 };
1109
1110 const struct inode_operations ecryptfs_dir_iops = {
1111         .create = ecryptfs_create,
1112         .lookup = ecryptfs_lookup,
1113         .link = ecryptfs_link,
1114         .unlink = ecryptfs_unlink,
1115         .symlink = ecryptfs_symlink,
1116         .mkdir = ecryptfs_mkdir,
1117         .rmdir = ecryptfs_rmdir,
1118         .mknod = ecryptfs_mknod,
1119         .rename = ecryptfs_rename,
1120         .permission = ecryptfs_permission,
1121         .setattr = ecryptfs_setattr,
1122         .setxattr = ecryptfs_setxattr,
1123         .getxattr = ecryptfs_getxattr,
1124         .listxattr = ecryptfs_listxattr,
1125         .removexattr = ecryptfs_removexattr
1126 };
1127
1128 const struct inode_operations ecryptfs_main_iops = {
1129         .permission = ecryptfs_permission,
1130         .setattr = ecryptfs_setattr,
1131         .getattr = ecryptfs_getattr,
1132         .setxattr = ecryptfs_setxattr,
1133         .getxattr = ecryptfs_getxattr,
1134         .listxattr = ecryptfs_listxattr,
1135         .removexattr = ecryptfs_removexattr
1136 };