vmscan: fix shrinker callback bug in fs/super.c
[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 <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 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
55 {
56         if (ecryptfs_inode_to_lower(inode) == (struct inode *)lower_inode)
57                 return 1;
58         return 0;
59 }
60
61 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
62 {
63         struct inode *lower_inode = opaque;
64
65         ecryptfs_set_inode_lower(inode, lower_inode);
66         fsstack_copy_attr_all(inode, lower_inode);
67         /* i_size will be overwritten for encrypted regular files */
68         fsstack_copy_inode_size(inode, lower_inode);
69         inode->i_ino = lower_inode->i_ino;
70         inode->i_version++;
71         inode->i_mapping->a_ops = &ecryptfs_aops;
72         inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
73
74         if (S_ISLNK(inode->i_mode))
75                 inode->i_op = &ecryptfs_symlink_iops;
76         else if (S_ISDIR(inode->i_mode))
77                 inode->i_op = &ecryptfs_dir_iops;
78         else
79                 inode->i_op = &ecryptfs_main_iops;
80
81         if (S_ISDIR(inode->i_mode))
82                 inode->i_fop = &ecryptfs_dir_fops;
83         else if (special_file(inode->i_mode))
84                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
85         else
86                 inode->i_fop = &ecryptfs_main_fops;
87
88         return 0;
89 }
90
91 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
92                                           struct super_block *sb)
93 {
94         struct inode *inode;
95
96         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
97                 return ERR_PTR(-EXDEV);
98         if (!igrab(lower_inode))
99                 return ERR_PTR(-ESTALE);
100         inode = iget5_locked(sb, (unsigned long)lower_inode,
101                              ecryptfs_inode_test, ecryptfs_inode_set,
102                              lower_inode);
103         if (!inode) {
104                 iput(lower_inode);
105                 return ERR_PTR(-EACCES);
106         }
107         if (!(inode->i_state & I_NEW))
108                 iput(lower_inode);
109
110         return inode;
111 }
112
113 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
114                                  struct super_block *sb)
115 {
116         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
117
118         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
119                 unlock_new_inode(inode);
120
121         return inode;
122 }
123
124 /**
125  * ecryptfs_interpose
126  * @lower_dentry: Existing dentry in the lower filesystem
127  * @dentry: ecryptfs' dentry
128  * @sb: ecryptfs's super_block
129  *
130  * Interposes upper and lower dentries.
131  *
132  * Returns zero on success; non-zero otherwise
133  */
134 static int ecryptfs_interpose(struct dentry *lower_dentry,
135                               struct dentry *dentry, struct super_block *sb)
136 {
137         struct inode *inode = ecryptfs_get_inode(lower_dentry->d_inode, sb);
138
139         if (IS_ERR(inode))
140                 return PTR_ERR(inode);
141         d_instantiate(dentry, inode);
142
143         return 0;
144 }
145
146 /**
147  * ecryptfs_create_underlying_file
148  * @lower_dir_inode: inode of the parent in the lower fs of the new file
149  * @dentry: New file's dentry
150  * @mode: The mode of the new file
151  *
152  * Creates the file in the lower file system.
153  *
154  * Returns zero on success; non-zero on error condition
155  */
156 static int
157 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
158                                 struct dentry *dentry, int mode)
159 {
160         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
161         return vfs_create(lower_dir_inode, lower_dentry, mode, NULL);
162 }
163
164 /**
165  * ecryptfs_do_create
166  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
167  * @ecryptfs_dentry: New file's dentry in ecryptfs
168  * @mode: The mode of the new file
169  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
170  *
171  * Creates the underlying file and the eCryptfs inode which will link to
172  * it. It will also update the eCryptfs directory inode to mimic the
173  * stat of the lower directory inode.
174  *
175  * Returns zero on success; non-zero on error condition
176  */
177 static int
178 ecryptfs_do_create(struct inode *directory_inode,
179                    struct dentry *ecryptfs_dentry, int mode)
180 {
181         int rc;
182         struct dentry *lower_dentry;
183         struct dentry *lower_dir_dentry;
184
185         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
186         lower_dir_dentry = lock_parent(lower_dentry);
187         if (IS_ERR(lower_dir_dentry)) {
188                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
189                                 "dentry\n");
190                 rc = PTR_ERR(lower_dir_dentry);
191                 goto out;
192         }
193         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
194                                              ecryptfs_dentry, mode);
195         if (rc) {
196                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
197                        "rc = [%d]\n", __func__, rc);
198                 goto out_lock;
199         }
200         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
201                                 directory_inode->i_sb);
202         if (rc) {
203                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
204                 goto out_lock;
205         }
206         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
207         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
208 out_lock:
209         unlock_dir(lower_dir_dentry);
210 out:
211         return rc;
212 }
213
214 /**
215  * ecryptfs_initialize_file
216  *
217  * Cause the file to be changed from a basic empty file to an ecryptfs
218  * file with a header and first data page.
219  *
220  * Returns zero on success
221  */
222 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
223 {
224         struct ecryptfs_crypt_stat *crypt_stat =
225                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
226         int rc = 0;
227
228         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
229                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
230                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
231                 goto out;
232         }
233         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
234         rc = ecryptfs_new_file_context(ecryptfs_dentry);
235         if (rc) {
236                 ecryptfs_printk(KERN_ERR, "Error creating new file "
237                                 "context; rc = [%d]\n", rc);
238                 goto out;
239         }
240         rc = ecryptfs_get_lower_file(ecryptfs_dentry,
241                                      ecryptfs_dentry->d_inode);
242         if (rc) {
243                 printk(KERN_ERR "%s: Error attempting to initialize "
244                         "the lower file for the dentry with name "
245                         "[%s]; rc = [%d]\n", __func__,
246                         ecryptfs_dentry->d_name.name, rc);
247                 goto out;
248         }
249         rc = ecryptfs_write_metadata(ecryptfs_dentry);
250         if (rc)
251                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
252         ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
253 out:
254         return rc;
255 }
256
257 /**
258  * ecryptfs_create
259  * @dir: The inode of the directory in which to create the file.
260  * @dentry: The eCryptfs dentry
261  * @mode: The mode of the new file.
262  * @nd: nameidata
263  *
264  * Creates a new file.
265  *
266  * Returns zero on success; non-zero on error condition
267  */
268 static int
269 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
270                 int mode, struct nameidata *nd)
271 {
272         int rc;
273
274         /* ecryptfs_do_create() calls ecryptfs_interpose() */
275         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode);
276         if (unlikely(rc)) {
277                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
278                                 "lower filesystem\n");
279                 goto out;
280         }
281         /* At this point, a file exists on "disk"; we need to make sure
282          * that this on disk file is prepared to be an ecryptfs file */
283         rc = ecryptfs_initialize_file(ecryptfs_dentry);
284 out:
285         return rc;
286 }
287
288 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
289 {
290         struct ecryptfs_crypt_stat *crypt_stat;
291         int rc;
292
293         rc = ecryptfs_get_lower_file(dentry, inode);
294         if (rc) {
295                 printk(KERN_ERR "%s: Error attempting to initialize "
296                         "the lower file for the dentry with name "
297                         "[%s]; rc = [%d]\n", __func__,
298                         dentry->d_name.name, rc);
299                 return rc;
300         }
301
302         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
303         /* TODO: lock for crypt_stat comparison */
304         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
305                 ecryptfs_set_default_sizes(crypt_stat);
306
307         rc = ecryptfs_read_and_validate_header_region(inode);
308         ecryptfs_put_lower_file(inode);
309         if (rc) {
310                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
311                 if (!rc)
312                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
313         }
314
315         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
316         return 0;
317 }
318
319 /**
320  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
321  */
322 static int ecryptfs_lookup_interpose(struct dentry *dentry,
323                                      struct dentry *lower_dentry,
324                                      struct inode *dir_inode)
325 {
326         struct inode *inode, *lower_inode = lower_dentry->d_inode;
327         struct ecryptfs_dentry_info *dentry_info;
328         struct vfsmount *lower_mnt;
329         int rc = 0;
330
331         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
332         fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
333         BUG_ON(!lower_dentry->d_count);
334
335         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
336         ecryptfs_set_dentry_private(dentry, dentry_info);
337         if (!dentry_info) {
338                 printk(KERN_ERR "%s: Out of memory whilst attempting "
339                        "to allocate ecryptfs_dentry_info struct\n",
340                         __func__);
341                 dput(lower_dentry);
342                 mntput(lower_mnt);
343                 d_drop(dentry);
344                 return -ENOMEM;
345         }
346         ecryptfs_set_dentry_lower(dentry, lower_dentry);
347         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
348
349         if (!lower_dentry->d_inode) {
350                 /* We want to add because we couldn't find in lower */
351                 d_add(dentry, NULL);
352                 return 0;
353         }
354         inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
355         if (IS_ERR(inode)) {
356                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
357                        __func__, PTR_ERR(inode));
358                 return PTR_ERR(inode);
359         }
360         if (S_ISREG(inode->i_mode)) {
361                 rc = ecryptfs_i_size_read(dentry, inode);
362                 if (rc) {
363                         make_bad_inode(inode);
364                         return rc;
365                 }
366         }
367
368         if (inode->i_state & I_NEW)
369                 unlock_new_inode(inode);
370         d_add(dentry, inode);
371
372         return rc;
373 }
374
375 /**
376  * ecryptfs_lookup
377  * @ecryptfs_dir_inode: The eCryptfs directory inode
378  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
379  * @ecryptfs_nd: nameidata; may be NULL
380  *
381  * Find a file on disk. If the file does not exist, then we'll add it to the
382  * dentry cache and continue on to read it from the disk.
383  */
384 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
385                                       struct dentry *ecryptfs_dentry,
386                                       struct nameidata *ecryptfs_nd)
387 {
388         char *encrypted_and_encoded_name = NULL;
389         size_t encrypted_and_encoded_name_size;
390         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
391         struct dentry *lower_dir_dentry, *lower_dentry;
392         int rc = 0;
393
394         if ((ecryptfs_dentry->d_name.len == 1
395              && !strcmp(ecryptfs_dentry->d_name.name, "."))
396             || (ecryptfs_dentry->d_name.len == 2
397                 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
398                 goto out_d_drop;
399         }
400         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
401         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
402         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
403                                       lower_dir_dentry,
404                                       ecryptfs_dentry->d_name.len);
405         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
406         if (IS_ERR(lower_dentry)) {
407                 rc = PTR_ERR(lower_dentry);
408                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
409                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
410                                 encrypted_and_encoded_name);
411                 goto out_d_drop;
412         }
413         if (lower_dentry->d_inode)
414                 goto interpose;
415         mount_crypt_stat = &ecryptfs_superblock_to_private(
416                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
417         if (!(mount_crypt_stat
418             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
419                 goto interpose;
420         dput(lower_dentry);
421         rc = ecryptfs_encrypt_and_encode_filename(
422                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
423                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
424                 ecryptfs_dentry->d_name.len);
425         if (rc) {
426                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
427                        "filename; rc = [%d]\n", __func__, rc);
428                 goto out_d_drop;
429         }
430         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
431         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
432                                       lower_dir_dentry,
433                                       encrypted_and_encoded_name_size);
434         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
435         if (IS_ERR(lower_dentry)) {
436                 rc = PTR_ERR(lower_dentry);
437                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
438                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
439                                 encrypted_and_encoded_name);
440                 goto out_d_drop;
441         }
442 interpose:
443         rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
444                                        ecryptfs_dir_inode);
445         goto out;
446 out_d_drop:
447         d_drop(ecryptfs_dentry);
448 out:
449         kfree(encrypted_and_encoded_name);
450         return ERR_PTR(rc);
451 }
452
453 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
454                          struct dentry *new_dentry)
455 {
456         struct dentry *lower_old_dentry;
457         struct dentry *lower_new_dentry;
458         struct dentry *lower_dir_dentry;
459         u64 file_size_save;
460         int rc;
461
462         file_size_save = i_size_read(old_dentry->d_inode);
463         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
464         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
465         dget(lower_old_dentry);
466         dget(lower_new_dentry);
467         lower_dir_dentry = lock_parent(lower_new_dentry);
468         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
469                       lower_new_dentry);
470         if (rc || !lower_new_dentry->d_inode)
471                 goto out_lock;
472         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
473         if (rc)
474                 goto out_lock;
475         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
476         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
477         old_dentry->d_inode->i_nlink =
478                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
479         i_size_write(new_dentry->d_inode, file_size_save);
480 out_lock:
481         unlock_dir(lower_dir_dentry);
482         dput(lower_new_dentry);
483         dput(lower_old_dentry);
484         return rc;
485 }
486
487 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
488 {
489         int rc = 0;
490         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
491         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
492         struct dentry *lower_dir_dentry;
493
494         dget(lower_dentry);
495         lower_dir_dentry = lock_parent(lower_dentry);
496         rc = vfs_unlink(lower_dir_inode, lower_dentry);
497         if (rc) {
498                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
499                 goto out_unlock;
500         }
501         fsstack_copy_attr_times(dir, lower_dir_inode);
502         dentry->d_inode->i_nlink =
503                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
504         dentry->d_inode->i_ctime = dir->i_ctime;
505         d_drop(dentry);
506 out_unlock:
507         unlock_dir(lower_dir_dentry);
508         dput(lower_dentry);
509         return rc;
510 }
511
512 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
513                             const char *symname)
514 {
515         int rc;
516         struct dentry *lower_dentry;
517         struct dentry *lower_dir_dentry;
518         char *encoded_symname;
519         size_t encoded_symlen;
520         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
521
522         lower_dentry = ecryptfs_dentry_to_lower(dentry);
523         dget(lower_dentry);
524         lower_dir_dentry = lock_parent(lower_dentry);
525         mount_crypt_stat = &ecryptfs_superblock_to_private(
526                 dir->i_sb)->mount_crypt_stat;
527         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
528                                                   &encoded_symlen,
529                                                   NULL,
530                                                   mount_crypt_stat, symname,
531                                                   strlen(symname));
532         if (rc)
533                 goto out_lock;
534         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
535                          encoded_symname);
536         kfree(encoded_symname);
537         if (rc || !lower_dentry->d_inode)
538                 goto out_lock;
539         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
540         if (rc)
541                 goto out_lock;
542         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
543         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
544 out_lock:
545         unlock_dir(lower_dir_dentry);
546         dput(lower_dentry);
547         if (!dentry->d_inode)
548                 d_drop(dentry);
549         return rc;
550 }
551
552 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
553 {
554         int rc;
555         struct dentry *lower_dentry;
556         struct dentry *lower_dir_dentry;
557
558         lower_dentry = ecryptfs_dentry_to_lower(dentry);
559         lower_dir_dentry = lock_parent(lower_dentry);
560         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
561         if (rc || !lower_dentry->d_inode)
562                 goto out;
563         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
564         if (rc)
565                 goto out;
566         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
567         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
568         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
569 out:
570         unlock_dir(lower_dir_dentry);
571         if (!dentry->d_inode)
572                 d_drop(dentry);
573         return rc;
574 }
575
576 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
577 {
578         struct dentry *lower_dentry;
579         struct dentry *lower_dir_dentry;
580         int rc;
581
582         lower_dentry = ecryptfs_dentry_to_lower(dentry);
583         dget(dentry);
584         lower_dir_dentry = lock_parent(lower_dentry);
585         dget(lower_dentry);
586         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
587         dput(lower_dentry);
588         if (!rc && dentry->d_inode)
589                 clear_nlink(dentry->d_inode);
590         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
591         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
592         unlock_dir(lower_dir_dentry);
593         if (!rc)
594                 d_drop(dentry);
595         dput(dentry);
596         return rc;
597 }
598
599 static int
600 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
601 {
602         int rc;
603         struct dentry *lower_dentry;
604         struct dentry *lower_dir_dentry;
605
606         lower_dentry = ecryptfs_dentry_to_lower(dentry);
607         lower_dir_dentry = lock_parent(lower_dentry);
608         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
609         if (rc || !lower_dentry->d_inode)
610                 goto out;
611         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
612         if (rc)
613                 goto out;
614         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
615         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
616 out:
617         unlock_dir(lower_dir_dentry);
618         if (!dentry->d_inode)
619                 d_drop(dentry);
620         return rc;
621 }
622
623 static int
624 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
625                 struct inode *new_dir, struct dentry *new_dentry)
626 {
627         int rc;
628         struct dentry *lower_old_dentry;
629         struct dentry *lower_new_dentry;
630         struct dentry *lower_old_dir_dentry;
631         struct dentry *lower_new_dir_dentry;
632         struct dentry *trap = NULL;
633
634         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
635         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
636         dget(lower_old_dentry);
637         dget(lower_new_dentry);
638         lower_old_dir_dentry = dget_parent(lower_old_dentry);
639         lower_new_dir_dentry = dget_parent(lower_new_dentry);
640         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
641         /* source should not be ancestor of target */
642         if (trap == lower_old_dentry) {
643                 rc = -EINVAL;
644                 goto out_lock;
645         }
646         /* target should not be ancestor of source */
647         if (trap == lower_new_dentry) {
648                 rc = -ENOTEMPTY;
649                 goto out_lock;
650         }
651         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
652                         lower_new_dir_dentry->d_inode, lower_new_dentry);
653         if (rc)
654                 goto out_lock;
655         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
656         if (new_dir != old_dir)
657                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
658 out_lock:
659         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
660         dput(lower_new_dir_dentry);
661         dput(lower_old_dir_dentry);
662         dput(lower_new_dentry);
663         dput(lower_old_dentry);
664         return rc;
665 }
666
667 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
668                                    size_t *bufsiz)
669 {
670         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
671         char *lower_buf;
672         size_t lower_bufsiz = PATH_MAX;
673         mm_segment_t old_fs;
674         int rc;
675
676         lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
677         if (!lower_buf) {
678                 rc = -ENOMEM;
679                 goto out;
680         }
681         old_fs = get_fs();
682         set_fs(get_ds());
683         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
684                                                    (char __user *)lower_buf,
685                                                    lower_bufsiz);
686         set_fs(old_fs);
687         if (rc < 0)
688                 goto out;
689         lower_bufsiz = rc;
690         rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
691                                                   lower_buf, lower_bufsiz);
692 out:
693         kfree(lower_buf);
694         return rc;
695 }
696
697 static int
698 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
699 {
700         char *kbuf;
701         size_t kbufsiz, copied;
702         int rc;
703
704         rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
705         if (rc)
706                 goto out;
707         copied = min_t(size_t, bufsiz, kbufsiz);
708         rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
709         kfree(kbuf);
710         fsstack_copy_attr_atime(dentry->d_inode,
711                                 ecryptfs_dentry_to_lower(dentry)->d_inode);
712 out:
713         return rc;
714 }
715
716 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
717 {
718         char *buf;
719         int len = PAGE_SIZE, rc;
720         mm_segment_t old_fs;
721
722         /* Released in ecryptfs_put_link(); only release here on error */
723         buf = kmalloc(len, GFP_KERNEL);
724         if (!buf) {
725                 buf = ERR_PTR(-ENOMEM);
726                 goto out;
727         }
728         old_fs = get_fs();
729         set_fs(get_ds());
730         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
731         set_fs(old_fs);
732         if (rc < 0) {
733                 kfree(buf);
734                 buf = ERR_PTR(rc);
735         } else
736                 buf[rc] = '\0';
737 out:
738         nd_set_link(nd, buf);
739         return NULL;
740 }
741
742 static void
743 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
744 {
745         char *buf = nd_get_link(nd);
746         if (!IS_ERR(buf)) {
747                 /* Free the char* */
748                 kfree(buf);
749         }
750 }
751
752 /**
753  * upper_size_to_lower_size
754  * @crypt_stat: Crypt_stat associated with file
755  * @upper_size: Size of the upper file
756  *
757  * Calculate the required size of the lower file based on the
758  * specified size of the upper file. This calculation is based on the
759  * number of headers in the underlying file and the extent size.
760  *
761  * Returns Calculated size of the lower file.
762  */
763 static loff_t
764 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
765                          loff_t upper_size)
766 {
767         loff_t lower_size;
768
769         lower_size = ecryptfs_lower_header_size(crypt_stat);
770         if (upper_size != 0) {
771                 loff_t num_extents;
772
773                 num_extents = upper_size >> crypt_stat->extent_shift;
774                 if (upper_size & ~crypt_stat->extent_mask)
775                         num_extents++;
776                 lower_size += (num_extents * crypt_stat->extent_size);
777         }
778         return lower_size;
779 }
780
781 /**
782  * truncate_upper
783  * @dentry: The ecryptfs layer dentry
784  * @ia: Address of the ecryptfs inode's attributes
785  * @lower_ia: Address of the lower inode's attributes
786  *
787  * Function to handle truncations modifying the size of the file. Note
788  * that the file sizes are interpolated. When expanding, we are simply
789  * writing strings of 0's out. When truncating, we truncate the upper
790  * inode and update the lower_ia according to the page index
791  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
792  * the caller must use lower_ia in a call to notify_change() to perform
793  * the truncation of the lower inode.
794  *
795  * Returns zero on success; non-zero otherwise
796  */
797 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
798                           struct iattr *lower_ia)
799 {
800         int rc = 0;
801         struct inode *inode = dentry->d_inode;
802         struct ecryptfs_crypt_stat *crypt_stat;
803         loff_t i_size = i_size_read(inode);
804         loff_t lower_size_before_truncate;
805         loff_t lower_size_after_truncate;
806
807         if (unlikely((ia->ia_size == i_size))) {
808                 lower_ia->ia_valid &= ~ATTR_SIZE;
809                 return 0;
810         }
811         rc = ecryptfs_get_lower_file(dentry, inode);
812         if (rc)
813                 return rc;
814         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
815         /* Switch on growing or shrinking file */
816         if (ia->ia_size > i_size) {
817                 char zero[] = { 0x00 };
818
819                 lower_ia->ia_valid &= ~ATTR_SIZE;
820                 /* Write a single 0 at the last position of the file;
821                  * this triggers code that will fill in 0's throughout
822                  * the intermediate portion of the previous end of the
823                  * file and the new and of the file */
824                 rc = ecryptfs_write(inode, zero,
825                                     (ia->ia_size - 1), 1);
826         } else { /* ia->ia_size < i_size_read(inode) */
827                 /* We're chopping off all the pages down to the page
828                  * in which ia->ia_size is located. Fill in the end of
829                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
830                  * PAGE_CACHE_SIZE with zeros. */
831                 size_t num_zeros = (PAGE_CACHE_SIZE
832                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
833
834
835                 /*
836                  * XXX(truncate) this should really happen at the begginning
837                  * of ->setattr.  But the code is too messy to that as part
838                  * of a larger patch.  ecryptfs is also totally missing out
839                  * on the inode_change_ok check at the beginning of
840                  * ->setattr while would include this.
841                  */
842                 rc = inode_newsize_ok(inode, ia->ia_size);
843                 if (rc)
844                         goto out;
845
846                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
847                         truncate_setsize(inode, ia->ia_size);
848                         lower_ia->ia_size = ia->ia_size;
849                         lower_ia->ia_valid |= ATTR_SIZE;
850                         goto out;
851                 }
852                 if (num_zeros) {
853                         char *zeros_virt;
854
855                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
856                         if (!zeros_virt) {
857                                 rc = -ENOMEM;
858                                 goto out;
859                         }
860                         rc = ecryptfs_write(inode, zeros_virt,
861                                             ia->ia_size, num_zeros);
862                         kfree(zeros_virt);
863                         if (rc) {
864                                 printk(KERN_ERR "Error attempting to zero out "
865                                        "the remainder of the end page on "
866                                        "reducing truncate; rc = [%d]\n", rc);
867                                 goto out;
868                         }
869                 }
870                 truncate_setsize(inode, ia->ia_size);
871                 rc = ecryptfs_write_inode_size_to_metadata(inode);
872                 if (rc) {
873                         printk(KERN_ERR "Problem with "
874                                "ecryptfs_write_inode_size_to_metadata; "
875                                "rc = [%d]\n", rc);
876                         goto out;
877                 }
878                 /* We are reducing the size of the ecryptfs file, and need to
879                  * know if we need to reduce the size of the lower file. */
880                 lower_size_before_truncate =
881                     upper_size_to_lower_size(crypt_stat, i_size);
882                 lower_size_after_truncate =
883                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
884                 if (lower_size_after_truncate < lower_size_before_truncate) {
885                         lower_ia->ia_size = lower_size_after_truncate;
886                         lower_ia->ia_valid |= ATTR_SIZE;
887                 } else
888                         lower_ia->ia_valid &= ~ATTR_SIZE;
889         }
890 out:
891         ecryptfs_put_lower_file(inode);
892         return rc;
893 }
894
895 /**
896  * ecryptfs_truncate
897  * @dentry: The ecryptfs layer dentry
898  * @new_length: The length to expand the file to
899  *
900  * Simple function that handles the truncation of an eCryptfs inode and
901  * its corresponding lower inode.
902  *
903  * Returns zero on success; non-zero otherwise
904  */
905 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
906 {
907         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
908         struct iattr lower_ia = { .ia_valid = 0 };
909         int rc;
910
911         rc = truncate_upper(dentry, &ia, &lower_ia);
912         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
913                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
914
915                 mutex_lock(&lower_dentry->d_inode->i_mutex);
916                 rc = notify_change(lower_dentry, &lower_ia);
917                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
918         }
919         return rc;
920 }
921
922 static int
923 ecryptfs_permission(struct inode *inode, int mask)
924 {
925         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
926 }
927
928 /**
929  * ecryptfs_setattr
930  * @dentry: dentry handle to the inode to modify
931  * @ia: Structure with flags of what to change and values
932  *
933  * Updates the metadata of an inode. If the update is to the size
934  * i.e. truncation, then ecryptfs_truncate will handle the size modification
935  * of both the ecryptfs inode and the lower inode.
936  *
937  * All other metadata changes will be passed right to the lower filesystem,
938  * and we will just update our inode to look like the lower.
939  */
940 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
941 {
942         int rc = 0;
943         struct dentry *lower_dentry;
944         struct iattr lower_ia;
945         struct inode *inode;
946         struct inode *lower_inode;
947         struct ecryptfs_crypt_stat *crypt_stat;
948
949         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
950         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
951                 ecryptfs_init_crypt_stat(crypt_stat);
952         inode = dentry->d_inode;
953         lower_inode = ecryptfs_inode_to_lower(inode);
954         lower_dentry = ecryptfs_dentry_to_lower(dentry);
955         mutex_lock(&crypt_stat->cs_mutex);
956         if (S_ISDIR(dentry->d_inode->i_mode))
957                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
958         else if (S_ISREG(dentry->d_inode->i_mode)
959                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
960                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
961                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
962
963                 mount_crypt_stat = &ecryptfs_superblock_to_private(
964                         dentry->d_sb)->mount_crypt_stat;
965                 rc = ecryptfs_get_lower_file(dentry, inode);
966                 if (rc) {
967                         mutex_unlock(&crypt_stat->cs_mutex);
968                         goto out;
969                 }
970                 rc = ecryptfs_read_metadata(dentry);
971                 ecryptfs_put_lower_file(inode);
972                 if (rc) {
973                         if (!(mount_crypt_stat->flags
974                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
975                                 rc = -EIO;
976                                 printk(KERN_WARNING "Either the lower file "
977                                        "is not in a valid eCryptfs format, "
978                                        "or the key could not be retrieved. "
979                                        "Plaintext passthrough mode is not "
980                                        "enabled; returning -EIO\n");
981                                 mutex_unlock(&crypt_stat->cs_mutex);
982                                 goto out;
983                         }
984                         rc = 0;
985                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
986                                                | ECRYPTFS_ENCRYPTED);
987                 }
988         }
989         mutex_unlock(&crypt_stat->cs_mutex);
990         if (S_ISREG(inode->i_mode)) {
991                 rc = filemap_write_and_wait(inode->i_mapping);
992                 if (rc)
993                         goto out;
994                 fsstack_copy_attr_all(inode, lower_inode);
995         }
996         memcpy(&lower_ia, ia, sizeof(lower_ia));
997         if (ia->ia_valid & ATTR_FILE)
998                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
999         if (ia->ia_valid & ATTR_SIZE) {
1000                 rc = truncate_upper(dentry, ia, &lower_ia);
1001                 if (rc < 0)
1002                         goto out;
1003         }
1004
1005         /*
1006          * mode change is for clearing setuid/setgid bits. Allow lower fs
1007          * to interpret this in its own way.
1008          */
1009         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
1010                 lower_ia.ia_valid &= ~ATTR_MODE;
1011
1012         mutex_lock(&lower_dentry->d_inode->i_mutex);
1013         rc = notify_change(lower_dentry, &lower_ia);
1014         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1015 out:
1016         fsstack_copy_attr_all(inode, lower_inode);
1017         return rc;
1018 }
1019
1020 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
1021                           struct kstat *stat)
1022 {
1023         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1024         int rc = 0;
1025
1026         mount_crypt_stat = &ecryptfs_superblock_to_private(
1027                                                 dentry->d_sb)->mount_crypt_stat;
1028         generic_fillattr(dentry->d_inode, stat);
1029         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1030                 char *target;
1031                 size_t targetsiz;
1032
1033                 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1034                 if (!rc) {
1035                         kfree(target);
1036                         stat->size = targetsiz;
1037                 }
1038         }
1039         return rc;
1040 }
1041
1042 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1043                      struct kstat *stat)
1044 {
1045         struct kstat lower_stat;
1046         int rc;
1047
1048         rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1049                          ecryptfs_dentry_to_lower(dentry), &lower_stat);
1050         if (!rc) {
1051                 fsstack_copy_attr_all(dentry->d_inode,
1052                                       ecryptfs_inode_to_lower(dentry->d_inode));
1053                 generic_fillattr(dentry->d_inode, stat);
1054                 stat->blocks = lower_stat.blocks;
1055         }
1056         return rc;
1057 }
1058
1059 int
1060 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1061                   size_t size, int flags)
1062 {
1063         int rc = 0;
1064         struct dentry *lower_dentry;
1065
1066         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1067         if (!lower_dentry->d_inode->i_op->setxattr) {
1068                 rc = -EOPNOTSUPP;
1069                 goto out;
1070         }
1071
1072         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1073 out:
1074         return rc;
1075 }
1076
1077 ssize_t
1078 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1079                         void *value, size_t size)
1080 {
1081         int rc = 0;
1082
1083         if (!lower_dentry->d_inode->i_op->getxattr) {
1084                 rc = -EOPNOTSUPP;
1085                 goto out;
1086         }
1087         mutex_lock(&lower_dentry->d_inode->i_mutex);
1088         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1089                                                    size);
1090         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1091 out:
1092         return rc;
1093 }
1094
1095 static ssize_t
1096 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1097                   size_t size)
1098 {
1099         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1100                                        value, size);
1101 }
1102
1103 static ssize_t
1104 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1105 {
1106         int rc = 0;
1107         struct dentry *lower_dentry;
1108
1109         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1110         if (!lower_dentry->d_inode->i_op->listxattr) {
1111                 rc = -EOPNOTSUPP;
1112                 goto out;
1113         }
1114         mutex_lock(&lower_dentry->d_inode->i_mutex);
1115         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1116         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1117 out:
1118         return rc;
1119 }
1120
1121 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1122 {
1123         int rc = 0;
1124         struct dentry *lower_dentry;
1125
1126         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1127         if (!lower_dentry->d_inode->i_op->removexattr) {
1128                 rc = -EOPNOTSUPP;
1129                 goto out;
1130         }
1131         mutex_lock(&lower_dentry->d_inode->i_mutex);
1132         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1133         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1134 out:
1135         return rc;
1136 }
1137
1138 const struct inode_operations ecryptfs_symlink_iops = {
1139         .readlink = ecryptfs_readlink,
1140         .follow_link = ecryptfs_follow_link,
1141         .put_link = ecryptfs_put_link,
1142         .permission = ecryptfs_permission,
1143         .setattr = ecryptfs_setattr,
1144         .getattr = ecryptfs_getattr_link,
1145         .setxattr = ecryptfs_setxattr,
1146         .getxattr = ecryptfs_getxattr,
1147         .listxattr = ecryptfs_listxattr,
1148         .removexattr = ecryptfs_removexattr
1149 };
1150
1151 const struct inode_operations ecryptfs_dir_iops = {
1152         .create = ecryptfs_create,
1153         .lookup = ecryptfs_lookup,
1154         .link = ecryptfs_link,
1155         .unlink = ecryptfs_unlink,
1156         .symlink = ecryptfs_symlink,
1157         .mkdir = ecryptfs_mkdir,
1158         .rmdir = ecryptfs_rmdir,
1159         .mknod = ecryptfs_mknod,
1160         .rename = ecryptfs_rename,
1161         .permission = ecryptfs_permission,
1162         .setattr = ecryptfs_setattr,
1163         .setxattr = ecryptfs_setxattr,
1164         .getxattr = ecryptfs_getxattr,
1165         .listxattr = ecryptfs_listxattr,
1166         .removexattr = ecryptfs_removexattr
1167 };
1168
1169 const struct inode_operations ecryptfs_main_iops = {
1170         .permission = ecryptfs_permission,
1171         .setattr = ecryptfs_setattr,
1172         .getattr = ecryptfs_getattr,
1173         .setxattr = ecryptfs_setxattr,
1174         .getxattr = ecryptfs_getxattr,
1175         .listxattr = ecryptfs_listxattr,
1176         .removexattr = ecryptfs_removexattr
1177 };