eCryptfs: fix dentry handling on create error, unlink, and inode destroy
[linux-2.6.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 "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_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
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 (rc) {
123                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
124                        "rc = [%d]\n", __FUNCTION__, rc);
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  *
145  * This is the code which will grow the file to its correct size.
146  */
147 static int grow_file(struct dentry *ecryptfs_dentry)
148 {
149         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
150         struct file fake_file;
151         struct ecryptfs_file_info tmp_file_info;
152         char zero_virt[] = { 0x00 };
153         int rc = 0;
154
155         memset(&fake_file, 0, sizeof(fake_file));
156         fake_file.f_path.dentry = ecryptfs_dentry;
157         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
158         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
159         ecryptfs_set_file_lower(
160                 &fake_file,
161                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
162         rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
163         i_size_write(ecryptfs_inode, 0);
164         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
165         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
166                 ECRYPTFS_NEW_FILE;
167         return rc;
168 }
169
170 /**
171  * ecryptfs_initialize_file
172  *
173  * Cause the file to be changed from a basic empty file to an ecryptfs
174  * file with a header and first data page.
175  *
176  * Returns zero on success
177  */
178 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
179 {
180         struct ecryptfs_crypt_stat *crypt_stat =
181                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
182         int rc = 0;
183
184         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
185                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
186                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
187                 goto out;
188         }
189         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
190         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
191         rc = ecryptfs_new_file_context(ecryptfs_dentry);
192         if (rc) {
193                 ecryptfs_printk(KERN_ERR, "Error creating new file "
194                                 "context; rc = [%d]\n", rc);
195                 goto out;
196         }
197         rc = ecryptfs_write_metadata(ecryptfs_dentry);
198         if (rc) {
199                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
200                 goto out;
201         }
202         rc = grow_file(ecryptfs_dentry);
203         if (rc)
204                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
205 out:
206         return rc;
207 }
208
209 /**
210  * ecryptfs_create
211  * @dir: The inode of the directory in which to create the file.
212  * @dentry: The eCryptfs dentry
213  * @mode: The mode of the new file.
214  * @nd: nameidata
215  *
216  * Creates a new file.
217  *
218  * Returns zero on success; non-zero on error condition
219  */
220 static int
221 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
222                 int mode, struct nameidata *nd)
223 {
224         int rc;
225
226         /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
227          * the crypt_stat->lower_file (persistent file) */
228         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
229         if (unlikely(rc)) {
230                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
231                                 "lower filesystem\n");
232                 goto out;
233         }
234         /* At this point, a file exists on "disk"; we need to make sure
235          * that this on disk file is prepared to be an ecryptfs file */
236         rc = ecryptfs_initialize_file(ecryptfs_dentry);
237 out:
238         return rc;
239 }
240
241 /**
242  * ecryptfs_lookup
243  * @dir: inode
244  * @dentry: The dentry
245  * @nd: nameidata, may be NULL
246  *
247  * Find a file on disk. If the file does not exist, then we'll add it to the
248  * dentry cache and continue on to read it from the disk.
249  */
250 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
251                                       struct nameidata *nd)
252 {
253         int rc = 0;
254         struct dentry *lower_dir_dentry;
255         struct dentry *lower_dentry;
256         struct vfsmount *lower_mnt;
257         char *encoded_name;
258         int encoded_namelen;
259         struct ecryptfs_crypt_stat *crypt_stat = NULL;
260         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
261         char *page_virt = NULL;
262         struct inode *lower_inode;
263         u64 file_size;
264
265         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
266         dentry->d_op = &ecryptfs_dops;
267         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
268             || (dentry->d_name.len == 2
269                 && !strcmp(dentry->d_name.name, ".."))) {
270                 d_drop(dentry);
271                 goto out;
272         }
273         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
274                                                    dentry->d_name.name,
275                                                    dentry->d_name.len,
276                                                    &encoded_name);
277         if (encoded_namelen < 0) {
278                 rc = encoded_namelen;
279                 d_drop(dentry);
280                 goto out;
281         }
282         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
283                         "= [%d]\n", encoded_name, encoded_namelen);
284         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
285                                       encoded_namelen - 1);
286         kfree(encoded_name);
287         if (IS_ERR(lower_dentry)) {
288                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
289                 rc = PTR_ERR(lower_dentry);
290                 d_drop(dentry);
291                 goto out;
292         }
293         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
294         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
295                 "d_name.name = [%s]\n", lower_dentry,
296                 lower_dentry->d_name.name);
297         lower_inode = lower_dentry->d_inode;
298         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
299         BUG_ON(!atomic_read(&lower_dentry->d_count));
300         ecryptfs_set_dentry_private(dentry,
301                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
302                                                      GFP_KERNEL));
303         if (!ecryptfs_dentry_to_private(dentry)) {
304                 rc = -ENOMEM;
305                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
306                                 "to allocate ecryptfs_dentry_info struct\n");
307                 goto out_dput;
308         }
309         ecryptfs_set_dentry_lower(dentry, lower_dentry);
310         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
311         if (!lower_dentry->d_inode) {
312                 /* We want to add because we couldn't find in lower */
313                 d_add(dentry, NULL);
314                 goto out;
315         }
316         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
317         if (rc) {
318                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
319                 goto out_dput;
320         }
321         if (S_ISDIR(lower_inode->i_mode)) {
322                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
323                 goto out;
324         }
325         if (S_ISLNK(lower_inode->i_mode)) {
326                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
327                 goto out;
328         }
329         if (special_file(lower_inode->i_mode)) {
330                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
331                 goto out;
332         }
333         if (!nd) {
334                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
335                                 "as we *think* we are about to unlink\n");
336                 goto out;
337         }
338         /* Released in this function */
339         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
340                                       GFP_USER);
341         if (!page_virt) {
342                 rc = -ENOMEM;
343                 ecryptfs_printk(KERN_ERR,
344                                 "Cannot ecryptfs_kmalloc a page\n");
345                 goto out_dput;
346         }
347         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
348         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
349                 ecryptfs_set_default_sizes(crypt_stat);
350         rc = ecryptfs_read_and_validate_header_region(page_virt,
351                                                       dentry->d_inode);
352         if (rc) {
353                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
354                 if (rc) {
355                         printk(KERN_DEBUG "Valid metadata not found in header "
356                                "region or xattr region; treating file as "
357                                "unencrypted\n");
358                         rc = 0;
359                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
360                         goto out;
361                 }
362                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
363         }
364         mount_crypt_stat = &ecryptfs_superblock_to_private(
365                 dentry->d_sb)->mount_crypt_stat;
366         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
367                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
368                         file_size = ((crypt_stat->extent_size
369                                       * crypt_stat->num_header_extents_at_front)
370                                      + i_size_read(lower_dentry->d_inode));
371                 else
372                         file_size = i_size_read(lower_dentry->d_inode);
373         } else {
374                 memcpy(&file_size, page_virt, sizeof(file_size));
375                 file_size = be64_to_cpu(file_size);
376         }
377         i_size_write(dentry->d_inode, (loff_t)file_size);
378         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
379         goto out;
380
381 out_dput:
382         dput(lower_dentry);
383         d_drop(dentry);
384 out:
385         return ERR_PTR(rc);
386 }
387
388 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
389                          struct dentry *new_dentry)
390 {
391         struct dentry *lower_old_dentry;
392         struct dentry *lower_new_dentry;
393         struct dentry *lower_dir_dentry;
394         u64 file_size_save;
395         int rc;
396
397         file_size_save = i_size_read(old_dentry->d_inode);
398         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
399         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
400         dget(lower_old_dentry);
401         dget(lower_new_dentry);
402         lower_dir_dentry = lock_parent(lower_new_dentry);
403         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
404                       lower_new_dentry);
405         if (rc || !lower_new_dentry->d_inode)
406                 goto out_lock;
407         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
408         if (rc)
409                 goto out_lock;
410         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
411         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
412         old_dentry->d_inode->i_nlink =
413                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
414         i_size_write(new_dentry->d_inode, file_size_save);
415 out_lock:
416         unlock_dir(lower_dir_dentry);
417         dput(lower_new_dentry);
418         dput(lower_old_dentry);
419         d_drop(lower_old_dentry);
420         d_drop(new_dentry);
421         d_drop(old_dentry);
422         return rc;
423 }
424
425 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
426 {
427         int rc = 0;
428         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
429         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
430
431         lock_parent(lower_dentry);
432         rc = vfs_unlink(lower_dir_inode, lower_dentry);
433         if (rc) {
434                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
435                 goto out_unlock;
436         }
437         fsstack_copy_attr_times(dir, lower_dir_inode);
438         dentry->d_inode->i_nlink =
439                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
440         dentry->d_inode->i_ctime = dir->i_ctime;
441         d_drop(dentry);
442 out_unlock:
443         unlock_parent(lower_dentry);
444         return rc;
445 }
446
447 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
448                             const char *symname)
449 {
450         int rc;
451         struct dentry *lower_dentry;
452         struct dentry *lower_dir_dentry;
453         umode_t mode;
454         char *encoded_symname;
455         int encoded_symlen;
456         struct ecryptfs_crypt_stat *crypt_stat = NULL;
457
458         lower_dentry = ecryptfs_dentry_to_lower(dentry);
459         dget(lower_dentry);
460         lower_dir_dentry = lock_parent(lower_dentry);
461         mode = S_IALLUGO;
462         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
463                                                   strlen(symname),
464                                                   &encoded_symname);
465         if (encoded_symlen < 0) {
466                 rc = encoded_symlen;
467                 goto out_lock;
468         }
469         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
470                          encoded_symname, mode);
471         kfree(encoded_symname);
472         if (rc || !lower_dentry->d_inode)
473                 goto out_lock;
474         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
475         if (rc)
476                 goto out_lock;
477         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
478         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
479 out_lock:
480         unlock_dir(lower_dir_dentry);
481         dput(lower_dentry);
482         if (!dentry->d_inode)
483                 d_drop(dentry);
484         return rc;
485 }
486
487 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
488 {
489         int rc;
490         struct dentry *lower_dentry;
491         struct dentry *lower_dir_dentry;
492
493         lower_dentry = ecryptfs_dentry_to_lower(dentry);
494         lower_dir_dentry = lock_parent(lower_dentry);
495         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
496         if (rc || !lower_dentry->d_inode)
497                 goto out;
498         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
499         if (rc)
500                 goto out;
501         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
502         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
503         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
504 out:
505         unlock_dir(lower_dir_dentry);
506         if (!dentry->d_inode)
507                 d_drop(dentry);
508         return rc;
509 }
510
511 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
512 {
513         struct dentry *lower_dentry;
514         struct dentry *lower_dir_dentry;
515         int rc;
516
517         lower_dentry = ecryptfs_dentry_to_lower(dentry);
518         dget(dentry);
519         lower_dir_dentry = lock_parent(lower_dentry);
520         dget(lower_dentry);
521         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
522         dput(lower_dentry);
523         if (!rc)
524                 d_delete(lower_dentry);
525         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
526         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
527         unlock_dir(lower_dir_dentry);
528         if (!rc)
529                 d_drop(dentry);
530         dput(dentry);
531         return rc;
532 }
533
534 static int
535 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
536 {
537         int rc;
538         struct dentry *lower_dentry;
539         struct dentry *lower_dir_dentry;
540
541         lower_dentry = ecryptfs_dentry_to_lower(dentry);
542         lower_dir_dentry = lock_parent(lower_dentry);
543         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
544         if (rc || !lower_dentry->d_inode)
545                 goto out;
546         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
547         if (rc)
548                 goto out;
549         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
550         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
551 out:
552         unlock_dir(lower_dir_dentry);
553         if (!dentry->d_inode)
554                 d_drop(dentry);
555         return rc;
556 }
557
558 static int
559 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
560                 struct inode *new_dir, struct dentry *new_dentry)
561 {
562         int rc;
563         struct dentry *lower_old_dentry;
564         struct dentry *lower_new_dentry;
565         struct dentry *lower_old_dir_dentry;
566         struct dentry *lower_new_dir_dentry;
567
568         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
569         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
570         dget(lower_old_dentry);
571         dget(lower_new_dentry);
572         lower_old_dir_dentry = dget_parent(lower_old_dentry);
573         lower_new_dir_dentry = dget_parent(lower_new_dentry);
574         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
575         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
576                         lower_new_dir_dentry->d_inode, lower_new_dentry);
577         if (rc)
578                 goto out_lock;
579         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
580         if (new_dir != old_dir)
581                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
582 out_lock:
583         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
584         dput(lower_new_dentry->d_parent);
585         dput(lower_old_dentry->d_parent);
586         dput(lower_new_dentry);
587         dput(lower_old_dentry);
588         return rc;
589 }
590
591 static int
592 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
593 {
594         int rc;
595         struct dentry *lower_dentry;
596         char *decoded_name;
597         char *lower_buf;
598         mm_segment_t old_fs;
599         struct ecryptfs_crypt_stat *crypt_stat;
600
601         lower_dentry = ecryptfs_dentry_to_lower(dentry);
602         if (!lower_dentry->d_inode->i_op ||
603             !lower_dentry->d_inode->i_op->readlink) {
604                 rc = -EINVAL;
605                 goto out;
606         }
607         /* Released in this function */
608         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
609         if (lower_buf == NULL) {
610                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
611                 rc = -ENOMEM;
612                 goto out;
613         }
614         old_fs = get_fs();
615         set_fs(get_ds());
616         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
617                         "lower_dentry->d_name.name = [%s]\n",
618                         lower_dentry->d_name.name);
619         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
620                                                    (char __user *)lower_buf,
621                                                    bufsiz);
622         set_fs(old_fs);
623         if (rc >= 0) {
624                 crypt_stat = NULL;
625                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
626                                               &decoded_name);
627                 if (rc == -ENOMEM)
628                         goto out_free_lower_buf;
629                 if (rc > 0) {
630                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
631                                         "to userspace: [%*s]\n", rc,
632                                         decoded_name);
633                         if (copy_to_user(buf, decoded_name, rc))
634                                 rc = -EFAULT;
635                 }
636                 kfree(decoded_name);
637                 fsstack_copy_attr_atime(dentry->d_inode,
638                                         lower_dentry->d_inode);
639         }
640 out_free_lower_buf:
641         kfree(lower_buf);
642 out:
643         return rc;
644 }
645
646 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
647 {
648         char *buf;
649         int len = PAGE_SIZE, rc;
650         mm_segment_t old_fs;
651
652         /* Released in ecryptfs_put_link(); only release here on error */
653         buf = kmalloc(len, GFP_KERNEL);
654         if (!buf) {
655                 rc = -ENOMEM;
656                 goto out;
657         }
658         old_fs = get_fs();
659         set_fs(get_ds());
660         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
661                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
662         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
663         buf[rc] = '\0';
664         set_fs(old_fs);
665         if (rc < 0)
666                 goto out_free;
667         rc = 0;
668         nd_set_link(nd, buf);
669         goto out;
670 out_free:
671         kfree(buf);
672 out:
673         return ERR_PTR(rc);
674 }
675
676 static void
677 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
678 {
679         /* Free the char* */
680         kfree(nd_get_link(nd));
681 }
682
683 /**
684  * upper_size_to_lower_size
685  * @crypt_stat: Crypt_stat associated with file
686  * @upper_size: Size of the upper file
687  *
688  * Calculate the requried size of the lower file based on the
689  * specified size of the upper file. This calculation is based on the
690  * number of headers in the underlying file and the extent size.
691  *
692  * Returns Calculated size of the lower file.
693  */
694 static loff_t
695 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
696                          loff_t upper_size)
697 {
698         loff_t lower_size;
699
700         lower_size = (crypt_stat->extent_size
701                       * crypt_stat->num_header_extents_at_front);
702         if (upper_size != 0) {
703                 loff_t num_extents;
704
705                 num_extents = upper_size >> crypt_stat->extent_shift;
706                 if (upper_size & ~crypt_stat->extent_mask)
707                         num_extents++;
708                 lower_size += (num_extents * crypt_stat->extent_size);
709         }
710         return lower_size;
711 }
712
713 /**
714  * ecryptfs_truncate
715  * @dentry: The ecryptfs layer dentry
716  * @new_length: The length to expand the file to
717  *
718  * Function to handle truncations modifying the size of the file. Note
719  * that the file sizes are interpolated. When expanding, we are simply
720  * writing strings of 0's out. When truncating, we need to modify the
721  * underlying file size according to the page index interpolations.
722  *
723  * Returns zero on success; non-zero otherwise
724  */
725 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
726 {
727         int rc = 0;
728         struct inode *inode = dentry->d_inode;
729         struct dentry *lower_dentry;
730         struct file fake_ecryptfs_file;
731         struct ecryptfs_crypt_stat *crypt_stat;
732         loff_t i_size = i_size_read(inode);
733         loff_t lower_size_before_truncate;
734         loff_t lower_size_after_truncate;
735
736         if (unlikely((new_length == i_size)))
737                 goto out;
738         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
739         /* Set up a fake ecryptfs file, this is used to interface with
740          * the file in the underlying filesystem so that the
741          * truncation has an effect there as well. */
742         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
743         fake_ecryptfs_file.f_path.dentry = dentry;
744         /* Released at out_free: label */
745         ecryptfs_set_file_private(&fake_ecryptfs_file,
746                                   kmem_cache_alloc(ecryptfs_file_info_cache,
747                                                    GFP_KERNEL));
748         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
749                 rc = -ENOMEM;
750                 goto out;
751         }
752         lower_dentry = ecryptfs_dentry_to_lower(dentry);
753         ecryptfs_set_file_lower(
754                 &fake_ecryptfs_file,
755                 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
756         /* Switch on growing or shrinking file */
757         if (new_length > i_size) {
758                 char zero[] = { 0x00 };
759
760                 /* Write a single 0 at the last position of the file;
761                  * this triggers code that will fill in 0's throughout
762                  * the intermediate portion of the previous end of the
763                  * file and the new and of the file */
764                 rc = ecryptfs_write(&fake_ecryptfs_file, zero,
765                                     (new_length - 1), 1);
766         } else { /* new_length < i_size_read(inode) */
767                 /* We're chopping off all the pages down do the page
768                  * in which new_length is located. Fill in the end of
769                  * that page from (new_length & ~PAGE_CACHE_MASK) to
770                  * PAGE_CACHE_SIZE with zeros. */
771                 size_t num_zeros = (PAGE_CACHE_SIZE
772                                     - (new_length & ~PAGE_CACHE_MASK));
773
774                 if (num_zeros) {
775                         char *zeros_virt;
776
777                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
778                         if (!zeros_virt) {
779                                 rc = -ENOMEM;
780                                 goto out_free;
781                         }
782                         rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
783                                             new_length, num_zeros);
784                         kfree(zeros_virt);
785                         if (rc) {
786                                 printk(KERN_ERR "Error attempting to zero out "
787                                        "the remainder of the end page on "
788                                        "reducing truncate; rc = [%d]\n", rc);
789                                 goto out_free;
790                         }
791                 }
792                 vmtruncate(inode, new_length);
793                 rc = ecryptfs_write_inode_size_to_metadata(inode);
794                 if (rc) {
795                         printk(KERN_ERR "Problem with "
796                                "ecryptfs_write_inode_size_to_metadata; "
797                                "rc = [%d]\n", rc);
798                         goto out_free;
799                 }
800                 /* We are reducing the size of the ecryptfs file, and need to
801                  * know if we need to reduce the size of the lower file. */
802                 lower_size_before_truncate =
803                     upper_size_to_lower_size(crypt_stat, i_size);
804                 lower_size_after_truncate =
805                     upper_size_to_lower_size(crypt_stat, new_length);
806                 if (lower_size_after_truncate < lower_size_before_truncate)
807                         vmtruncate(lower_dentry->d_inode,
808                                    lower_size_after_truncate);
809         }
810 out_free:
811         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
812                 kmem_cache_free(ecryptfs_file_info_cache,
813                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
814 out:
815         return rc;
816 }
817
818 static int
819 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
820 {
821         int rc;
822
823         if (nd) {
824                 struct vfsmount *vfsmnt_save = nd->mnt;
825                 struct dentry *dentry_save = nd->dentry;
826
827                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
828                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
829                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
830                 nd->mnt = vfsmnt_save;
831                 nd->dentry = dentry_save;
832         } else
833                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
834         return rc;
835 }
836
837 /**
838  * ecryptfs_setattr
839  * @dentry: dentry handle to the inode to modify
840  * @ia: Structure with flags of what to change and values
841  *
842  * Updates the metadata of an inode. If the update is to the size
843  * i.e. truncation, then ecryptfs_truncate will handle the size modification
844  * of both the ecryptfs inode and the lower inode.
845  *
846  * All other metadata changes will be passed right to the lower filesystem,
847  * and we will just update our inode to look like the lower.
848  */
849 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
850 {
851         int rc = 0;
852         struct dentry *lower_dentry;
853         struct inode *inode;
854         struct inode *lower_inode;
855         struct ecryptfs_crypt_stat *crypt_stat;
856
857         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
858         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
859                 ecryptfs_init_crypt_stat(crypt_stat);
860         inode = dentry->d_inode;
861         lower_inode = ecryptfs_inode_to_lower(inode);
862         lower_dentry = ecryptfs_dentry_to_lower(dentry);
863         mutex_lock(&crypt_stat->cs_mutex);
864         if (S_ISDIR(dentry->d_inode->i_mode))
865                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
866         else if (S_ISREG(dentry->d_inode->i_mode)
867                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
868                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
869                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
870
871                 mount_crypt_stat = &ecryptfs_superblock_to_private(
872                         dentry->d_sb)->mount_crypt_stat;
873                 rc = ecryptfs_read_metadata(dentry);
874                 if (rc) {
875                         if (!(mount_crypt_stat->flags
876                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
877                                 rc = -EIO;
878                                 printk(KERN_WARNING "Attempt to read file that "
879                                        "is not in a valid eCryptfs format, "
880                                        "and plaintext passthrough mode is not "
881                                        "enabled; returning -EIO\n");
882
883                                 mutex_unlock(&crypt_stat->cs_mutex);
884                                 goto out;
885                         }
886                         rc = 0;
887                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
888                         mutex_unlock(&crypt_stat->cs_mutex);
889                         goto out;
890                 }
891         }
892         mutex_unlock(&crypt_stat->cs_mutex);
893         if (ia->ia_valid & ATTR_SIZE) {
894                 ecryptfs_printk(KERN_DEBUG,
895                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
896                                 ia->ia_valid, ATTR_SIZE);
897                 rc = ecryptfs_truncate(dentry, ia->ia_size);
898                 /* ecryptfs_truncate handles resizing of the lower file */
899                 ia->ia_valid &= ~ATTR_SIZE;
900                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
901                                 ia->ia_valid);
902                 if (rc < 0)
903                         goto out;
904         }
905
906         /*
907          * mode change is for clearing setuid/setgid bits. Allow lower fs
908          * to interpret this in its own way.
909          */
910         if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
911                 ia->ia_valid &= ~ATTR_MODE;
912
913         rc = notify_change(lower_dentry, ia);
914 out:
915         fsstack_copy_attr_all(inode, lower_inode, NULL);
916         return rc;
917 }
918
919 int
920 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
921                   size_t size, int flags)
922 {
923         int rc = 0;
924         struct dentry *lower_dentry;
925
926         lower_dentry = ecryptfs_dentry_to_lower(dentry);
927         if (!lower_dentry->d_inode->i_op->setxattr) {
928                 rc = -ENOSYS;
929                 goto out;
930         }
931         mutex_lock(&lower_dentry->d_inode->i_mutex);
932         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
933                                                    size, flags);
934         mutex_unlock(&lower_dentry->d_inode->i_mutex);
935 out:
936         return rc;
937 }
938
939 ssize_t
940 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
941                         void *value, size_t size)
942 {
943         int rc = 0;
944
945         if (!lower_dentry->d_inode->i_op->getxattr) {
946                 rc = -ENOSYS;
947                 goto out;
948         }
949         mutex_lock(&lower_dentry->d_inode->i_mutex);
950         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
951                                                    size);
952         mutex_unlock(&lower_dentry->d_inode->i_mutex);
953 out:
954         return rc;
955 }
956
957 ssize_t
958 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
959                   size_t size)
960 {
961         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
962                                        value, size);
963 }
964
965 static ssize_t
966 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
967 {
968         int rc = 0;
969         struct dentry *lower_dentry;
970
971         lower_dentry = ecryptfs_dentry_to_lower(dentry);
972         if (!lower_dentry->d_inode->i_op->listxattr) {
973                 rc = -ENOSYS;
974                 goto out;
975         }
976         mutex_lock(&lower_dentry->d_inode->i_mutex);
977         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
978         mutex_unlock(&lower_dentry->d_inode->i_mutex);
979 out:
980         return rc;
981 }
982
983 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
984 {
985         int rc = 0;
986         struct dentry *lower_dentry;
987
988         lower_dentry = ecryptfs_dentry_to_lower(dentry);
989         if (!lower_dentry->d_inode->i_op->removexattr) {
990                 rc = -ENOSYS;
991                 goto out;
992         }
993         mutex_lock(&lower_dentry->d_inode->i_mutex);
994         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
995         mutex_unlock(&lower_dentry->d_inode->i_mutex);
996 out:
997         return rc;
998 }
999
1000 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1001 {
1002         if ((ecryptfs_inode_to_lower(inode)
1003              == (struct inode *)candidate_lower_inode))
1004                 return 1;
1005         else
1006                 return 0;
1007 }
1008
1009 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1010 {
1011         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1012         return 0;
1013 }
1014
1015 const struct inode_operations ecryptfs_symlink_iops = {
1016         .readlink = ecryptfs_readlink,
1017         .follow_link = ecryptfs_follow_link,
1018         .put_link = ecryptfs_put_link,
1019         .permission = ecryptfs_permission,
1020         .setattr = ecryptfs_setattr,
1021         .setxattr = ecryptfs_setxattr,
1022         .getxattr = ecryptfs_getxattr,
1023         .listxattr = ecryptfs_listxattr,
1024         .removexattr = ecryptfs_removexattr
1025 };
1026
1027 const struct inode_operations ecryptfs_dir_iops = {
1028         .create = ecryptfs_create,
1029         .lookup = ecryptfs_lookup,
1030         .link = ecryptfs_link,
1031         .unlink = ecryptfs_unlink,
1032         .symlink = ecryptfs_symlink,
1033         .mkdir = ecryptfs_mkdir,
1034         .rmdir = ecryptfs_rmdir,
1035         .mknod = ecryptfs_mknod,
1036         .rename = ecryptfs_rename,
1037         .permission = ecryptfs_permission,
1038         .setattr = ecryptfs_setattr,
1039         .setxattr = ecryptfs_setxattr,
1040         .getxattr = ecryptfs_getxattr,
1041         .listxattr = ecryptfs_listxattr,
1042         .removexattr = ecryptfs_removexattr
1043 };
1044
1045 const struct inode_operations ecryptfs_main_iops = {
1046         .permission = ecryptfs_permission,
1047         .setattr = ecryptfs_setattr,
1048         .setxattr = ecryptfs_setxattr,
1049         .getxattr = ecryptfs_getxattr,
1050         .listxattr = ecryptfs_listxattr,
1051         .removexattr = ecryptfs_removexattr
1052 };