Merge ../linus
[linux-2.6] / 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) 2004-2006 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 "ecryptfs_kernel.h"
35
36 static struct dentry *lock_parent(struct dentry *dentry)
37 {
38         struct dentry *dir;
39
40         dir = dget(dentry->d_parent);
41         mutex_lock(&(dir->d_inode->i_mutex));
42         return dir;
43 }
44
45 static void unlock_parent(struct dentry *dentry)
46 {
47         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
48         dput(dentry->d_parent);
49 }
50
51 static void unlock_dir(struct dentry *dir)
52 {
53         mutex_unlock(&dir->d_inode->i_mutex);
54         dput(dir);
55 }
56
57 /**
58  * ecryptfs_create_underlying_file
59  * @lower_dir_inode: inode of the parent in the lower fs of the new file
60  * @lower_dentry: New file's dentry in the lower fs
61  * @ecryptfs_dentry: New file's dentry in ecryptfs
62  * @mode: The mode of the new file
63  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
64  *
65  * Creates the file in the lower file system.
66  *
67  * Returns zero on success; non-zero on error condition
68  */
69 static int
70 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
71                                 struct dentry *dentry, int mode,
72                                 struct nameidata *nd)
73 {
74         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
75         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
76         struct dentry *dentry_save;
77         struct vfsmount *vfsmount_save;
78         int rc;
79
80         dentry_save = nd->dentry;
81         vfsmount_save = nd->mnt;
82         nd->dentry = lower_dentry;
83         nd->mnt = lower_mnt;
84         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
85         nd->dentry = dentry_save;
86         nd->mnt = vfsmount_save;
87         return rc;
88 }
89
90 /**
91  * ecryptfs_do_create
92  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
93  * @ecryptfs_dentry: New file's dentry in ecryptfs
94  * @mode: The mode of the new file
95  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
96  *
97  * Creates the underlying file and the eCryptfs inode which will link to
98  * it. It will also update the eCryptfs directory inode to mimic the
99  * stat of the lower directory inode.
100  *
101  * Returns zero on success; non-zero on error condition
102  */
103 static int
104 ecryptfs_do_create(struct inode *directory_inode,
105                    struct dentry *ecryptfs_dentry, int mode,
106                    struct nameidata *nd)
107 {
108         int rc;
109         struct dentry *lower_dentry;
110         struct dentry *lower_dir_dentry;
111
112         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
113         lower_dir_dentry = lock_parent(lower_dentry);
114         if (unlikely(IS_ERR(lower_dir_dentry))) {
115                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
116                                 "dentry\n");
117                 rc = PTR_ERR(lower_dir_dentry);
118                 goto out;
119         }
120         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
121                                              ecryptfs_dentry, mode, nd);
122         if (unlikely(rc)) {
123                 ecryptfs_printk(KERN_ERR,
124                                 "Failure to create underlying file\n");
125                 goto out_lock;
126         }
127         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
128                                 directory_inode->i_sb, 0);
129         if (rc) {
130                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
131                 goto out_lock;
132         }
133         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
134         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
135 out_lock:
136         unlock_dir(lower_dir_dentry);
137 out:
138         return rc;
139 }
140
141 /**
142  * grow_file
143  * @ecryptfs_dentry: the ecryptfs dentry
144  * @lower_file: The lower file
145  * @inode: The ecryptfs inode
146  * @lower_inode: The lower inode
147  *
148  * This is the code which will grow the file to its correct size.
149  */
150 static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
151                      struct inode *inode, struct inode *lower_inode)
152 {
153         int rc = 0;
154         struct file fake_file;
155         struct ecryptfs_file_info tmp_file_info;
156
157         memset(&fake_file, 0, sizeof(fake_file));
158         fake_file.f_path.dentry = ecryptfs_dentry;
159         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
160         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
161         ecryptfs_set_file_lower(&fake_file, lower_file);
162         rc = ecryptfs_fill_zeros(&fake_file, 1);
163         if (rc) {
164                 ECRYPTFS_SET_FLAG(
165                         ecryptfs_inode_to_private(inode)->crypt_stat.flags,
166                         ECRYPTFS_SECURITY_WARNING);
167                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
168                                 "in file; rc = [%d]\n", rc);
169                 goto out;
170         }
171         i_size_write(inode, 0);
172         ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
173         ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
174                           ECRYPTFS_NEW_FILE);
175 out:
176         return rc;
177 }
178
179 /**
180  * ecryptfs_initialize_file
181  *
182  * Cause the file to be changed from a basic empty file to an ecryptfs
183  * file with a header and first data page.
184  *
185  * Returns zero on success
186  */
187 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
188 {
189         int rc = 0;
190         int lower_flags;
191         struct ecryptfs_crypt_stat *crypt_stat;
192         struct dentry *lower_dentry;
193         struct file *lower_file;
194         struct inode *inode, *lower_inode;
195         struct vfsmount *lower_mnt;
196
197         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
198         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
199                         lower_dentry->d_name.name);
200         inode = ecryptfs_dentry->d_inode;
201         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
202         lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
203 #if BITS_PER_LONG != 32
204         lower_flags |= O_LARGEFILE;
205 #endif
206         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
207         /* Corresponding fput() at end of this function */
208         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
209                                            lower_flags))) {
210                 ecryptfs_printk(KERN_ERR,
211                                 "Error opening dentry; rc = [%i]\n", rc);
212                 goto out;
213         }
214         lower_inode = lower_dentry->d_inode;
215         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
216                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
217                 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
218                 goto out_fput;
219         }
220         ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
221         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
222         rc = ecryptfs_new_file_context(ecryptfs_dentry);
223         if (rc) {
224                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
225                                 "context\n");
226                 goto out_fput;
227         }
228         rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
229         if (rc) {
230                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
231                 goto out_fput;
232         }
233         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
234 out_fput:
235         if ((rc = ecryptfs_close_lower_file(lower_file)))
236                 printk(KERN_ERR "Error closing lower_file\n");
237 out:
238         return rc;
239 }
240
241 /**
242  * ecryptfs_create
243  * @dir: The inode of the directory in which to create the file.
244  * @dentry: The eCryptfs dentry
245  * @mode: The mode of the new file.
246  * @nd: nameidata
247  *
248  * Creates a new file.
249  *
250  * Returns zero on success; non-zero on error condition
251  */
252 static int
253 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
254                 int mode, struct nameidata *nd)
255 {
256         int rc;
257
258         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
259         if (unlikely(rc)) {
260                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
261                                 "lower filesystem\n");
262                 goto out;
263         }
264         /* At this point, a file exists on "disk"; we need to make sure
265          * that this on disk file is prepared to be an ecryptfs file */
266         rc = ecryptfs_initialize_file(ecryptfs_dentry);
267 out:
268         return rc;
269 }
270
271 /**
272  * ecryptfs_lookup
273  * @dir: inode
274  * @dentry: The dentry
275  * @nd: nameidata, may be NULL
276  *
277  * Find a file on disk. If the file does not exist, then we'll add it to the
278  * dentry cache and continue on to read it from the disk.
279  */
280 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
281                                       struct nameidata *nd)
282 {
283         int rc = 0;
284         struct dentry *lower_dir_dentry;
285         struct dentry *lower_dentry;
286         struct vfsmount *lower_mnt;
287         char *encoded_name;
288         unsigned int encoded_namelen;
289         struct ecryptfs_crypt_stat *crypt_stat = NULL;
290         char *page_virt = NULL;
291         struct inode *lower_inode;
292         u64 file_size;
293
294         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
295         dentry->d_op = &ecryptfs_dops;
296         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
297             || (dentry->d_name.len == 2
298                 && !strcmp(dentry->d_name.name, ".."))) {
299                 d_drop(dentry);
300                 goto out;
301         }
302         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
303                                                    dentry->d_name.name,
304                                                    dentry->d_name.len,
305                                                    &encoded_name);
306         if (encoded_namelen < 0) {
307                 rc = encoded_namelen;
308                 d_drop(dentry);
309                 goto out;
310         }
311         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
312                         "= [%d]\n", encoded_name, encoded_namelen);
313         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
314                                       encoded_namelen - 1);
315         kfree(encoded_name);
316         if (IS_ERR(lower_dentry)) {
317                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
318                 rc = PTR_ERR(lower_dentry);
319                 d_drop(dentry);
320                 goto out;
321         }
322         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
323         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
324                 "d_name.name = [%s]\n", lower_dentry,
325                 lower_dentry->d_name.name);
326         lower_inode = lower_dentry->d_inode;
327         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
328         BUG_ON(!atomic_read(&lower_dentry->d_count));
329         ecryptfs_set_dentry_private(dentry,
330                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
331                                                      GFP_KERNEL));
332         if (!ecryptfs_dentry_to_private(dentry)) {
333                 rc = -ENOMEM;
334                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
335                                 "to allocate ecryptfs_dentry_info struct\n");
336                 goto out_dput;
337         }
338         ecryptfs_set_dentry_lower(dentry, lower_dentry);
339         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
340         if (!lower_dentry->d_inode) {
341                 /* We want to add because we couldn't find in lower */
342                 d_add(dentry, NULL);
343                 goto out;
344         }
345         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
346         if (rc) {
347                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
348                 goto out_dput;
349         }
350         if (S_ISDIR(lower_inode->i_mode)) {
351                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
352                 goto out;
353         }
354         if (S_ISLNK(lower_inode->i_mode)) {
355                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
356                 goto out;
357         }
358         if (!nd) {
359                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
360                                 "as we *think* we are about to unlink\n");
361                 goto out;
362         }
363         /* Released in this function */
364         page_virt =
365             (char *)kmem_cache_alloc(ecryptfs_header_cache_2,
366                                      GFP_USER);
367         if (!page_virt) {
368                 rc = -ENOMEM;
369                 ecryptfs_printk(KERN_ERR,
370                                 "Cannot ecryptfs_kmalloc a page\n");
371                 goto out_dput;
372         }
373         memset(page_virt, 0, PAGE_CACHE_SIZE);
374         rc = ecryptfs_read_header_region(page_virt, lower_dentry, nd->mnt);
375         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
376         if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
377                 ecryptfs_set_default_sizes(crypt_stat);
378         if (rc) {
379                 rc = 0;
380                 ecryptfs_printk(KERN_WARNING, "Error reading header region;"
381                                 " assuming unencrypted\n");
382         } else {
383                 if (!contains_ecryptfs_marker(page_virt
384                                               + ECRYPTFS_FILE_SIZE_BYTES)) {
385                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
386                         goto out;
387                 }
388                 memcpy(&file_size, page_virt, sizeof(file_size));
389                 file_size = be64_to_cpu(file_size);
390                 i_size_write(dentry->d_inode, (loff_t)file_size);
391         }
392         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
393         goto out;
394
395 out_dput:
396         dput(lower_dentry);
397         d_drop(dentry);
398 out:
399         return ERR_PTR(rc);
400 }
401
402 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
403                          struct dentry *new_dentry)
404 {
405         struct dentry *lower_old_dentry;
406         struct dentry *lower_new_dentry;
407         struct dentry *lower_dir_dentry;
408         u64 file_size_save;
409         int rc;
410
411         file_size_save = i_size_read(old_dentry->d_inode);
412         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
413         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
414         dget(lower_old_dentry);
415         dget(lower_new_dentry);
416         lower_dir_dentry = lock_parent(lower_new_dentry);
417         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
418                       lower_new_dentry);
419         if (rc || !lower_new_dentry->d_inode)
420                 goto out_lock;
421         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
422         if (rc)
423                 goto out_lock;
424         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
425         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
426         old_dentry->d_inode->i_nlink =
427                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
428         i_size_write(new_dentry->d_inode, file_size_save);
429 out_lock:
430         unlock_dir(lower_dir_dentry);
431         dput(lower_new_dentry);
432         dput(lower_old_dentry);
433         d_drop(lower_old_dentry);
434         d_drop(new_dentry);
435         d_drop(old_dentry);
436         return rc;
437 }
438
439 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
440 {
441         int rc = 0;
442         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
443         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
444
445         lock_parent(lower_dentry);
446         rc = vfs_unlink(lower_dir_inode, lower_dentry);
447         if (rc) {
448                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
449                 goto out_unlock;
450         }
451         fsstack_copy_attr_times(dir, lower_dir_inode);
452         dentry->d_inode->i_nlink =
453                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
454         dentry->d_inode->i_ctime = dir->i_ctime;
455 out_unlock:
456         unlock_parent(lower_dentry);
457         return rc;
458 }
459
460 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
461                             const char *symname)
462 {
463         int rc;
464         struct dentry *lower_dentry;
465         struct dentry *lower_dir_dentry;
466         umode_t mode;
467         char *encoded_symname;
468         unsigned int encoded_symlen;
469         struct ecryptfs_crypt_stat *crypt_stat = NULL;
470
471         lower_dentry = ecryptfs_dentry_to_lower(dentry);
472         dget(lower_dentry);
473         lower_dir_dentry = lock_parent(lower_dentry);
474         mode = S_IALLUGO;
475         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
476                                                   strlen(symname),
477                                                   &encoded_symname);
478         if (encoded_symlen < 0) {
479                 rc = encoded_symlen;
480                 goto out_lock;
481         }
482         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
483                          encoded_symname, mode);
484         kfree(encoded_symname);
485         if (rc || !lower_dentry->d_inode)
486                 goto out_lock;
487         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
488         if (rc)
489                 goto out_lock;
490         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
491         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
492 out_lock:
493         unlock_dir(lower_dir_dentry);
494         dput(lower_dentry);
495         if (!dentry->d_inode)
496                 d_drop(dentry);
497         return rc;
498 }
499
500 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
501 {
502         int rc;
503         struct dentry *lower_dentry;
504         struct dentry *lower_dir_dentry;
505
506         lower_dentry = ecryptfs_dentry_to_lower(dentry);
507         lower_dir_dentry = lock_parent(lower_dentry);
508         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
509         if (rc || !lower_dentry->d_inode)
510                 goto out;
511         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
512         if (rc)
513                 goto out;
514         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
515         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
516         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
517 out:
518         unlock_dir(lower_dir_dentry);
519         if (!dentry->d_inode)
520                 d_drop(dentry);
521         return rc;
522 }
523
524 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
525 {
526         struct dentry *lower_dentry;
527         struct dentry *lower_dir_dentry;
528         int rc;
529
530         lower_dentry = ecryptfs_dentry_to_lower(dentry);
531         dget(dentry);
532         lower_dir_dentry = lock_parent(lower_dentry);
533         dget(lower_dentry);
534         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
535         dput(lower_dentry);
536         if (!rc)
537                 d_delete(lower_dentry);
538         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
539         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
540         unlock_dir(lower_dir_dentry);
541         if (!rc)
542                 d_drop(dentry);
543         dput(dentry);
544         return rc;
545 }
546
547 static int
548 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
549 {
550         int rc;
551         struct dentry *lower_dentry;
552         struct dentry *lower_dir_dentry;
553
554         lower_dentry = ecryptfs_dentry_to_lower(dentry);
555         lower_dir_dentry = lock_parent(lower_dentry);
556         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
557         if (rc || !lower_dentry->d_inode)
558                 goto out;
559         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
560         if (rc)
561                 goto out;
562         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
563         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
564 out:
565         unlock_dir(lower_dir_dentry);
566         if (!dentry->d_inode)
567                 d_drop(dentry);
568         return rc;
569 }
570
571 static int
572 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
573                 struct inode *new_dir, struct dentry *new_dentry)
574 {
575         int rc;
576         struct dentry *lower_old_dentry;
577         struct dentry *lower_new_dentry;
578         struct dentry *lower_old_dir_dentry;
579         struct dentry *lower_new_dir_dentry;
580
581         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
582         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
583         dget(lower_old_dentry);
584         dget(lower_new_dentry);
585         lower_old_dir_dentry = dget_parent(lower_old_dentry);
586         lower_new_dir_dentry = dget_parent(lower_new_dentry);
587         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
588         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
589                         lower_new_dir_dentry->d_inode, lower_new_dentry);
590         if (rc)
591                 goto out_lock;
592         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
593         if (new_dir != old_dir)
594                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
595 out_lock:
596         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
597         dput(lower_new_dentry->d_parent);
598         dput(lower_old_dentry->d_parent);
599         dput(lower_new_dentry);
600         dput(lower_old_dentry);
601         return rc;
602 }
603
604 static int
605 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
606 {
607         int rc;
608         struct dentry *lower_dentry;
609         char *decoded_name;
610         char *lower_buf;
611         mm_segment_t old_fs;
612         struct ecryptfs_crypt_stat *crypt_stat;
613
614         lower_dentry = ecryptfs_dentry_to_lower(dentry);
615         if (!lower_dentry->d_inode->i_op ||
616             !lower_dentry->d_inode->i_op->readlink) {
617                 rc = -EINVAL;
618                 goto out;
619         }
620         /* Released in this function */
621         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
622         if (lower_buf == NULL) {
623                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
624                 rc = -ENOMEM;
625                 goto out;
626         }
627         old_fs = get_fs();
628         set_fs(get_ds());
629         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
630                         "lower_dentry->d_name.name = [%s]\n",
631                         lower_dentry->d_name.name);
632         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
633                                                    (char __user *)lower_buf,
634                                                    bufsiz);
635         set_fs(old_fs);
636         if (rc >= 0) {
637                 crypt_stat = NULL;
638                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
639                                               &decoded_name);
640                 if (rc == -ENOMEM)
641                         goto out_free_lower_buf;
642                 if (rc > 0) {
643                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
644                                         "to userspace: [%*s]\n", rc,
645                                         decoded_name);
646                         if (copy_to_user(buf, decoded_name, rc))
647                                 rc = -EFAULT;
648                 }
649                 kfree(decoded_name);
650                 fsstack_copy_attr_atime(dentry->d_inode,
651                                         lower_dentry->d_inode);
652         }
653 out_free_lower_buf:
654         kfree(lower_buf);
655 out:
656         return rc;
657 }
658
659 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
660 {
661         char *buf;
662         int len = PAGE_SIZE, rc;
663         mm_segment_t old_fs;
664
665         /* Released in ecryptfs_put_link(); only release here on error */
666         buf = kmalloc(len, GFP_KERNEL);
667         if (!buf) {
668                 rc = -ENOMEM;
669                 goto out;
670         }
671         old_fs = get_fs();
672         set_fs(get_ds());
673         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
674                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
675         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
676         buf[rc] = '\0';
677         set_fs(old_fs);
678         if (rc < 0)
679                 goto out_free;
680         rc = 0;
681         nd_set_link(nd, buf);
682         goto out;
683 out_free:
684         kfree(buf);
685 out:
686         return ERR_PTR(rc);
687 }
688
689 static void
690 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
691 {
692         /* Free the char* */
693         kfree(nd_get_link(nd));
694 }
695
696 /**
697  * upper_size_to_lower_size
698  * @crypt_stat: Crypt_stat associated with file
699  * @upper_size: Size of the upper file
700  *
701  * Calculate the requried size of the lower file based on the
702  * specified size of the upper file. This calculation is based on the
703  * number of headers in the underlying file and the extent size.
704  *
705  * Returns Calculated size of the lower file.
706  */
707 static loff_t
708 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
709                          loff_t upper_size)
710 {
711         loff_t lower_size;
712
713         lower_size = ( crypt_stat->header_extent_size
714                        * crypt_stat->num_header_extents_at_front );
715         if (upper_size != 0) {
716                 loff_t num_extents;
717
718                 num_extents = upper_size >> crypt_stat->extent_shift;
719                 if (upper_size & ~crypt_stat->extent_mask)
720                         num_extents++;
721                 lower_size += (num_extents * crypt_stat->extent_size);
722         }
723         return lower_size;
724 }
725
726 /**
727  * ecryptfs_truncate
728  * @dentry: The ecryptfs layer dentry
729  * @new_length: The length to expand the file to
730  *
731  * Function to handle truncations modifying the size of the file. Note
732  * that the file sizes are interpolated. When expanding, we are simply
733  * writing strings of 0's out. When truncating, we need to modify the
734  * underlying file size according to the page index interpolations.
735  *
736  * Returns zero on success; non-zero otherwise
737  */
738 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
739 {
740         int rc = 0;
741         struct inode *inode = dentry->d_inode;
742         struct dentry *lower_dentry;
743         struct vfsmount *lower_mnt;
744         struct file fake_ecryptfs_file, *lower_file = NULL;
745         struct ecryptfs_crypt_stat *crypt_stat;
746         loff_t i_size = i_size_read(inode);
747         loff_t lower_size_before_truncate;
748         loff_t lower_size_after_truncate;
749
750         if (unlikely((new_length == i_size)))
751                 goto out;
752         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
753         /* Set up a fake ecryptfs file, this is used to interface with
754          * the file in the underlying filesystem so that the
755          * truncation has an effect there as well. */
756         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
757         fake_ecryptfs_file.f_path.dentry = dentry;
758         /* Released at out_free: label */
759         ecryptfs_set_file_private(&fake_ecryptfs_file,
760                                   kmem_cache_alloc(ecryptfs_file_info_cache,
761                                                    GFP_KERNEL));
762         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
763                 rc = -ENOMEM;
764                 goto out;
765         }
766         lower_dentry = ecryptfs_dentry_to_lower(dentry);
767         /* This dget & mntget is released through fput at out_fput: */
768         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
769         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
770                                            O_RDWR))) {
771                 ecryptfs_printk(KERN_ERR,
772                                 "Error opening dentry; rc = [%i]\n", rc);
773                 goto out_free;
774         }
775         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
776         /* Switch on growing or shrinking file */
777         if (new_length > i_size) {
778                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
779                 if (rc) {
780                         ecryptfs_printk(KERN_ERR,
781                                         "Problem with fill_zeros\n");
782                         goto out_fput;
783                 }
784                 i_size_write(inode, new_length);
785                 rc = ecryptfs_write_inode_size_to_header(lower_file,
786                                                          lower_dentry->d_inode,
787                                                          inode);
788                 if (rc) {
789                         ecryptfs_printk(KERN_ERR,
790                                         "Problem with ecryptfs_write"
791                                         "_inode_size\n");
792                         goto out_fput;
793                 }
794         } else { /* new_length < i_size_read(inode) */
795                 vmtruncate(inode, new_length);
796                 ecryptfs_write_inode_size_to_header(lower_file,
797                                                     lower_dentry->d_inode,
798                                                     inode);
799                 /* We are reducing the size of the ecryptfs file, and need to
800                  * know if we need to reduce the size of the lower file. */
801                 lower_size_before_truncate =
802                     upper_size_to_lower_size(crypt_stat, i_size);
803                 lower_size_after_truncate =
804                     upper_size_to_lower_size(crypt_stat, new_length);
805                 if (lower_size_after_truncate < lower_size_before_truncate)
806                         vmtruncate(lower_dentry->d_inode,
807                                    lower_size_after_truncate);
808         }
809         /* Update the access times */
810         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
811                 = CURRENT_TIME;
812         mark_inode_dirty_sync(inode);
813 out_fput:
814         if ((rc = ecryptfs_close_lower_file(lower_file)))
815                 printk(KERN_ERR "Error closing lower_file\n");
816 out_free:
817         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
818                 kmem_cache_free(ecryptfs_file_info_cache,
819                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
820 out:
821         return rc;
822 }
823
824 static int
825 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
826 {
827         int rc;
828
829         if (nd) {
830                 struct vfsmount *vfsmnt_save = nd->mnt;
831                 struct dentry *dentry_save = nd->dentry;
832
833                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
834                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
835                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
836                 nd->mnt = vfsmnt_save;
837                 nd->dentry = dentry_save;
838         } else
839                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
840         return rc;
841 }
842
843 /**
844  * ecryptfs_setattr
845  * @dentry: dentry handle to the inode to modify
846  * @ia: Structure with flags of what to change and values
847  *
848  * Updates the metadata of an inode. If the update is to the size
849  * i.e. truncation, then ecryptfs_truncate will handle the size modification
850  * of both the ecryptfs inode and the lower inode.
851  *
852  * All other metadata changes will be passed right to the lower filesystem,
853  * and we will just update our inode to look like the lower.
854  */
855 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
856 {
857         int rc = 0;
858         struct dentry *lower_dentry;
859         struct inode *inode;
860         struct inode *lower_inode;
861         struct ecryptfs_crypt_stat *crypt_stat;
862
863         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
864         lower_dentry = ecryptfs_dentry_to_lower(dentry);
865         inode = dentry->d_inode;
866         lower_inode = ecryptfs_inode_to_lower(inode);
867         if (ia->ia_valid & ATTR_SIZE) {
868                 ecryptfs_printk(KERN_DEBUG,
869                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
870                                 ia->ia_valid, ATTR_SIZE);
871                 rc = ecryptfs_truncate(dentry, ia->ia_size);
872                 /* ecryptfs_truncate handles resizing of the lower file */
873                 ia->ia_valid &= ~ATTR_SIZE;
874                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
875                                 ia->ia_valid);
876                 if (rc < 0)
877                         goto out;
878         }
879         rc = notify_change(lower_dentry, ia);
880 out:
881         fsstack_copy_attr_all(inode, lower_inode, NULL);
882         return rc;
883 }
884
885 static int
886 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
887                   size_t size, int flags)
888 {
889         int rc = 0;
890         struct dentry *lower_dentry;
891
892         lower_dentry = ecryptfs_dentry_to_lower(dentry);
893         if (!lower_dentry->d_inode->i_op->setxattr) {
894                 rc = -ENOSYS;
895                 goto out;
896         }
897         mutex_lock(&lower_dentry->d_inode->i_mutex);
898         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
899                                                    size, flags);
900         mutex_unlock(&lower_dentry->d_inode->i_mutex);
901 out:
902         return rc;
903 }
904
905 static ssize_t
906 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
907                   size_t size)
908 {
909         int rc = 0;
910         struct dentry *lower_dentry;
911
912         lower_dentry = ecryptfs_dentry_to_lower(dentry);
913         if (!lower_dentry->d_inode->i_op->getxattr) {
914                 rc = -ENOSYS;
915                 goto out;
916         }
917         mutex_lock(&lower_dentry->d_inode->i_mutex);
918         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
919                                                    size);
920         mutex_unlock(&lower_dentry->d_inode->i_mutex);
921 out:
922         return rc;
923 }
924
925 static ssize_t
926 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
927 {
928         int rc = 0;
929         struct dentry *lower_dentry;
930
931         lower_dentry = ecryptfs_dentry_to_lower(dentry);
932         if (!lower_dentry->d_inode->i_op->listxattr) {
933                 rc = -ENOSYS;
934                 goto out;
935         }
936         mutex_lock(&lower_dentry->d_inode->i_mutex);
937         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
938         mutex_unlock(&lower_dentry->d_inode->i_mutex);
939 out:
940         return rc;
941 }
942
943 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
944 {
945         int rc = 0;
946         struct dentry *lower_dentry;
947
948         lower_dentry = ecryptfs_dentry_to_lower(dentry);
949         if (!lower_dentry->d_inode->i_op->removexattr) {
950                 rc = -ENOSYS;
951                 goto out;
952         }
953         mutex_lock(&lower_dentry->d_inode->i_mutex);
954         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
955         mutex_unlock(&lower_dentry->d_inode->i_mutex);
956 out:
957         return rc;
958 }
959
960 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
961 {
962         if ((ecryptfs_inode_to_lower(inode)
963              == (struct inode *)candidate_lower_inode))
964                 return 1;
965         else
966                 return 0;
967 }
968
969 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
970 {
971         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
972         return 0;
973 }
974
975 struct inode_operations ecryptfs_symlink_iops = {
976         .readlink = ecryptfs_readlink,
977         .follow_link = ecryptfs_follow_link,
978         .put_link = ecryptfs_put_link,
979         .permission = ecryptfs_permission,
980         .setattr = ecryptfs_setattr,
981         .setxattr = ecryptfs_setxattr,
982         .getxattr = ecryptfs_getxattr,
983         .listxattr = ecryptfs_listxattr,
984         .removexattr = ecryptfs_removexattr
985 };
986
987 struct inode_operations ecryptfs_dir_iops = {
988         .create = ecryptfs_create,
989         .lookup = ecryptfs_lookup,
990         .link = ecryptfs_link,
991         .unlink = ecryptfs_unlink,
992         .symlink = ecryptfs_symlink,
993         .mkdir = ecryptfs_mkdir,
994         .rmdir = ecryptfs_rmdir,
995         .mknod = ecryptfs_mknod,
996         .rename = ecryptfs_rename,
997         .permission = ecryptfs_permission,
998         .setattr = ecryptfs_setattr,
999         .setxattr = ecryptfs_setxattr,
1000         .getxattr = ecryptfs_getxattr,
1001         .listxattr = ecryptfs_listxattr,
1002         .removexattr = ecryptfs_removexattr
1003 };
1004
1005 struct inode_operations ecryptfs_main_iops = {
1006         .permission = ecryptfs_permission,
1007         .setattr = ecryptfs_setattr,
1008         .setxattr = ecryptfs_setxattr,
1009         .getxattr = ecryptfs_getxattr,
1010         .listxattr = ecryptfs_listxattr,
1011         .removexattr = ecryptfs_removexattr
1012 };