ecryptfs: Fix warning in ecryptfs_process_response()
[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 <asm/unaligned.h>
36 #include "ecryptfs_kernel.h"
37
38 static struct dentry *lock_parent(struct dentry *dentry)
39 {
40         struct dentry *dir;
41
42         dir = dget_parent(dentry);
43         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
44         return dir;
45 }
46
47 static void unlock_dir(struct dentry *dir)
48 {
49         mutex_unlock(&dir->d_inode->i_mutex);
50         dput(dir);
51 }
52
53 /**
54  * ecryptfs_create_underlying_file
55  * @lower_dir_inode: inode of the parent in the lower fs of the new file
56  * @dentry: New file's dentry
57  * @mode: The mode of the new file
58  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
59  *
60  * Creates the file in the lower file system.
61  *
62  * Returns zero on success; non-zero on error condition
63  */
64 static int
65 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
66                                 struct dentry *dentry, int mode,
67                                 struct nameidata *nd)
68 {
69         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
70         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
71         struct dentry *dentry_save;
72         struct vfsmount *vfsmount_save;
73         int rc;
74
75         dentry_save = nd->path.dentry;
76         vfsmount_save = nd->path.mnt;
77         nd->path.dentry = lower_dentry;
78         nd->path.mnt = lower_mnt;
79         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
80         nd->path.dentry = dentry_save;
81         nd->path.mnt = vfsmount_save;
82         return rc;
83 }
84
85 /**
86  * ecryptfs_do_create
87  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
88  * @ecryptfs_dentry: New file's dentry in ecryptfs
89  * @mode: The mode of the new file
90  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
91  *
92  * Creates the underlying file and the eCryptfs inode which will link to
93  * it. It will also update the eCryptfs directory inode to mimic the
94  * stat of the lower directory inode.
95  *
96  * Returns zero on success; non-zero on error condition
97  */
98 static int
99 ecryptfs_do_create(struct inode *directory_inode,
100                    struct dentry *ecryptfs_dentry, int mode,
101                    struct nameidata *nd)
102 {
103         int rc;
104         struct dentry *lower_dentry;
105         struct dentry *lower_dir_dentry;
106
107         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
108         lower_dir_dentry = lock_parent(lower_dentry);
109         if (IS_ERR(lower_dir_dentry)) {
110                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
111                                 "dentry\n");
112                 rc = PTR_ERR(lower_dir_dentry);
113                 goto out;
114         }
115         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
116                                              ecryptfs_dentry, mode, nd);
117         if (rc) {
118                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
119                        "rc = [%d]\n", __func__, rc);
120                 goto out_lock;
121         }
122         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
123                                 directory_inode->i_sb, 0);
124         if (rc) {
125                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
126                 goto out_lock;
127         }
128         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
129         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
130 out_lock:
131         unlock_dir(lower_dir_dentry);
132 out:
133         return rc;
134 }
135
136 /**
137  * grow_file
138  * @ecryptfs_dentry: the eCryptfs dentry
139  *
140  * This is the code which will grow the file to its correct size.
141  */
142 static int grow_file(struct dentry *ecryptfs_dentry)
143 {
144         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
145         char zero_virt[] = { 0x00 };
146         int rc = 0;
147
148         rc = ecryptfs_write(ecryptfs_inode, zero_virt, 0, 1);
149         i_size_write(ecryptfs_inode, 0);
150         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
151         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
152                 ECRYPTFS_NEW_FILE;
153         return rc;
154 }
155
156 /**
157  * ecryptfs_initialize_file
158  *
159  * Cause the file to be changed from a basic empty file to an ecryptfs
160  * file with a header and first data page.
161  *
162  * Returns zero on success
163  */
164 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
165 {
166         struct ecryptfs_crypt_stat *crypt_stat =
167                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
168         int rc = 0;
169
170         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
171                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
172                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
173                 goto out;
174         }
175         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
176         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
177         rc = ecryptfs_new_file_context(ecryptfs_dentry);
178         if (rc) {
179                 ecryptfs_printk(KERN_ERR, "Error creating new file "
180                                 "context; rc = [%d]\n", rc);
181                 goto out;
182         }
183         if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
184                 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
185                 if (rc) {
186                         printk(KERN_ERR "%s: Error attempting to initialize "
187                                "the persistent file for the dentry with name "
188                                "[%s]; rc = [%d]\n", __func__,
189                                ecryptfs_dentry->d_name.name, rc);
190                         goto out;
191                 }
192         }
193         rc = ecryptfs_write_metadata(ecryptfs_dentry);
194         if (rc) {
195                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
196                 goto out;
197         }
198         rc = grow_file(ecryptfs_dentry);
199         if (rc)
200                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
201 out:
202         return rc;
203 }
204
205 /**
206  * ecryptfs_create
207  * @dir: The inode of the directory in which to create the file.
208  * @dentry: The eCryptfs dentry
209  * @mode: The mode of the new file.
210  * @nd: nameidata
211  *
212  * Creates a new file.
213  *
214  * Returns zero on success; non-zero on error condition
215  */
216 static int
217 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
218                 int mode, struct nameidata *nd)
219 {
220         int rc;
221
222         /* ecryptfs_do_create() calls ecryptfs_interpose() */
223         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
224         if (unlikely(rc)) {
225                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
226                                 "lower filesystem\n");
227                 goto out;
228         }
229         /* At this point, a file exists on "disk"; we need to make sure
230          * that this on disk file is prepared to be an ecryptfs file */
231         rc = ecryptfs_initialize_file(ecryptfs_dentry);
232 out:
233         return rc;
234 }
235
236 /**
237  * ecryptfs_lookup_and_interpose_lower - Perform a lookup
238  */
239 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
240                                         struct dentry *lower_dentry,
241                                         struct inode *ecryptfs_dir_inode,
242                                         struct nameidata *ecryptfs_nd)
243 {
244         struct dentry *lower_dir_dentry;
245         struct vfsmount *lower_mnt;
246         struct inode *lower_inode;
247         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
248         struct ecryptfs_crypt_stat *crypt_stat;
249         char *page_virt = NULL;
250         u64 file_size;
251         int rc = 0;
252
253         lower_dir_dentry = lower_dentry->d_parent;
254         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
255                                    ecryptfs_dentry->d_parent));
256         lower_inode = lower_dentry->d_inode;
257         fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
258         BUG_ON(!atomic_read(&lower_dentry->d_count));
259         ecryptfs_set_dentry_private(ecryptfs_dentry,
260                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
261                                                      GFP_KERNEL));
262         if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
263                 rc = -ENOMEM;
264                 printk(KERN_ERR "%s: Out of memory whilst attempting "
265                        "to allocate ecryptfs_dentry_info struct\n",
266                         __func__);
267                 goto out_dput;
268         }
269         ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
270         ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
271         if (!lower_dentry->d_inode) {
272                 /* We want to add because we couldn't find in lower */
273                 d_add(ecryptfs_dentry, NULL);
274                 goto out;
275         }
276         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
277                                 ecryptfs_dir_inode->i_sb,
278                                 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
279         if (rc) {
280                 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
281                        __func__, rc);
282                 goto out;
283         }
284         if (S_ISDIR(lower_inode->i_mode))
285                 goto out;
286         if (S_ISLNK(lower_inode->i_mode))
287                 goto out;
288         if (special_file(lower_inode->i_mode))
289                 goto out;
290         if (!ecryptfs_nd)
291                 goto out;
292         /* Released in this function */
293         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
294         if (!page_virt) {
295                 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
296                        __func__);
297                 rc = -ENOMEM;
298                 goto out;
299         }
300         if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
301                 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
302                 if (rc) {
303                         printk(KERN_ERR "%s: Error attempting to initialize "
304                                "the persistent file for the dentry with name "
305                                "[%s]; rc = [%d]\n", __func__,
306                                ecryptfs_dentry->d_name.name, rc);
307                         goto out_free_kmem;
308                 }
309         }
310         crypt_stat = &ecryptfs_inode_to_private(
311                                         ecryptfs_dentry->d_inode)->crypt_stat;
312         /* TODO: lock for crypt_stat comparison */
313         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
314                         ecryptfs_set_default_sizes(crypt_stat);
315         rc = ecryptfs_read_and_validate_header_region(page_virt,
316                                                       ecryptfs_dentry->d_inode);
317         if (rc) {
318                 memset(page_virt, 0, PAGE_CACHE_SIZE);
319                 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
320                                                              ecryptfs_dentry);
321                 if (rc) {
322                         rc = 0;
323                         goto out_free_kmem;
324                 }
325                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
326         }
327         mount_crypt_stat = &ecryptfs_superblock_to_private(
328                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
329         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
330                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
331                         file_size = (crypt_stat->metadata_size
332                                      + i_size_read(lower_dentry->d_inode));
333                 else
334                         file_size = i_size_read(lower_dentry->d_inode);
335         } else {
336                 file_size = get_unaligned_be64(page_virt);
337         }
338         i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
339 out_free_kmem:
340         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
341         goto out;
342 out_dput:
343         dput(lower_dentry);
344         d_drop(ecryptfs_dentry);
345 out:
346         return rc;
347 }
348
349 /**
350  * ecryptfs_lookup
351  * @ecryptfs_dir_inode: The eCryptfs directory inode
352  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
353  * @ecryptfs_nd: nameidata; may be NULL
354  *
355  * Find a file on disk. If the file does not exist, then we'll add it to the
356  * dentry cache and continue on to read it from the disk.
357  */
358 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
359                                       struct dentry *ecryptfs_dentry,
360                                       struct nameidata *ecryptfs_nd)
361 {
362         char *encrypted_and_encoded_name = NULL;
363         size_t encrypted_and_encoded_name_size;
364         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
365         struct dentry *lower_dir_dentry, *lower_dentry;
366         int rc = 0;
367
368         ecryptfs_dentry->d_op = &ecryptfs_dops;
369         if ((ecryptfs_dentry->d_name.len == 1
370              && !strcmp(ecryptfs_dentry->d_name.name, "."))
371             || (ecryptfs_dentry->d_name.len == 2
372                 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
373                 goto out_d_drop;
374         }
375         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
376         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
377         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
378                                       lower_dir_dentry,
379                                       ecryptfs_dentry->d_name.len);
380         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
381         if (IS_ERR(lower_dentry)) {
382                 rc = PTR_ERR(lower_dentry);
383                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
384                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
385                                 encrypted_and_encoded_name);
386                 goto out_d_drop;
387         }
388         if (lower_dentry->d_inode)
389                 goto lookup_and_interpose;
390         mount_crypt_stat = &ecryptfs_superblock_to_private(
391                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
392         if (!(mount_crypt_stat
393             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
394                 goto lookup_and_interpose;
395         dput(lower_dentry);
396         rc = ecryptfs_encrypt_and_encode_filename(
397                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
398                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
399                 ecryptfs_dentry->d_name.len);
400         if (rc) {
401                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
402                        "filename; rc = [%d]\n", __func__, rc);
403                 goto out_d_drop;
404         }
405         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
406         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
407                                       lower_dir_dentry,
408                                       encrypted_and_encoded_name_size - 1);
409         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
410         if (IS_ERR(lower_dentry)) {
411                 rc = PTR_ERR(lower_dentry);
412                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
413                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
414                                 encrypted_and_encoded_name);
415                 goto out_d_drop;
416         }
417 lookup_and_interpose:
418         rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
419                                                  ecryptfs_dir_inode,
420                                                  ecryptfs_nd);
421         goto out;
422 out_d_drop:
423         d_drop(ecryptfs_dentry);
424 out:
425         kfree(encrypted_and_encoded_name);
426         return ERR_PTR(rc);
427 }
428
429 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
430                          struct dentry *new_dentry)
431 {
432         struct dentry *lower_old_dentry;
433         struct dentry *lower_new_dentry;
434         struct dentry *lower_dir_dentry;
435         u64 file_size_save;
436         int rc;
437
438         file_size_save = i_size_read(old_dentry->d_inode);
439         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
440         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
441         dget(lower_old_dentry);
442         dget(lower_new_dentry);
443         lower_dir_dentry = lock_parent(lower_new_dentry);
444         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
445                       lower_new_dentry);
446         if (rc || !lower_new_dentry->d_inode)
447                 goto out_lock;
448         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
449         if (rc)
450                 goto out_lock;
451         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
452         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
453         old_dentry->d_inode->i_nlink =
454                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
455         i_size_write(new_dentry->d_inode, file_size_save);
456 out_lock:
457         unlock_dir(lower_dir_dentry);
458         dput(lower_new_dentry);
459         dput(lower_old_dentry);
460         return rc;
461 }
462
463 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
464 {
465         int rc = 0;
466         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
467         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
468         struct dentry *lower_dir_dentry;
469
470         dget(lower_dentry);
471         lower_dir_dentry = lock_parent(lower_dentry);
472         rc = vfs_unlink(lower_dir_inode, lower_dentry);
473         if (rc) {
474                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
475                 goto out_unlock;
476         }
477         fsstack_copy_attr_times(dir, lower_dir_inode);
478         dentry->d_inode->i_nlink =
479                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
480         dentry->d_inode->i_ctime = dir->i_ctime;
481         d_drop(dentry);
482 out_unlock:
483         unlock_dir(lower_dir_dentry);
484         dput(lower_dentry);
485         return rc;
486 }
487
488 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
489                             const char *symname)
490 {
491         int rc;
492         struct dentry *lower_dentry;
493         struct dentry *lower_dir_dentry;
494         char *encoded_symname;
495         size_t encoded_symlen;
496         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
497
498         lower_dentry = ecryptfs_dentry_to_lower(dentry);
499         dget(lower_dentry);
500         lower_dir_dentry = lock_parent(lower_dentry);
501         mount_crypt_stat = &ecryptfs_superblock_to_private(
502                 dir->i_sb)->mount_crypt_stat;
503         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
504                                                   &encoded_symlen,
505                                                   NULL,
506                                                   mount_crypt_stat, symname,
507                                                   strlen(symname));
508         if (rc)
509                 goto out_lock;
510         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
511                          encoded_symname);
512         kfree(encoded_symname);
513         if (rc || !lower_dentry->d_inode)
514                 goto out_lock;
515         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
516         if (rc)
517                 goto out_lock;
518         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
519         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
520 out_lock:
521         unlock_dir(lower_dir_dentry);
522         dput(lower_dentry);
523         if (!dentry->d_inode)
524                 d_drop(dentry);
525         return rc;
526 }
527
528 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
529 {
530         int rc;
531         struct dentry *lower_dentry;
532         struct dentry *lower_dir_dentry;
533
534         lower_dentry = ecryptfs_dentry_to_lower(dentry);
535         lower_dir_dentry = lock_parent(lower_dentry);
536         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
537         if (rc || !lower_dentry->d_inode)
538                 goto out;
539         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
540         if (rc)
541                 goto out;
542         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
543         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
544         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
545 out:
546         unlock_dir(lower_dir_dentry);
547         if (!dentry->d_inode)
548                 d_drop(dentry);
549         return rc;
550 }
551
552 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
553 {
554         struct dentry *lower_dentry;
555         struct dentry *lower_dir_dentry;
556         int rc;
557
558         lower_dentry = ecryptfs_dentry_to_lower(dentry);
559         dget(dentry);
560         lower_dir_dentry = lock_parent(lower_dentry);
561         dget(lower_dentry);
562         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
563         dput(lower_dentry);
564         if (!rc)
565                 d_delete(lower_dentry);
566         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
567         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
568         unlock_dir(lower_dir_dentry);
569         if (!rc)
570                 d_drop(dentry);
571         dput(dentry);
572         return rc;
573 }
574
575 static int
576 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
577 {
578         int rc;
579         struct dentry *lower_dentry;
580         struct dentry *lower_dir_dentry;
581
582         lower_dentry = ecryptfs_dentry_to_lower(dentry);
583         lower_dir_dentry = lock_parent(lower_dentry);
584         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
585         if (rc || !lower_dentry->d_inode)
586                 goto out;
587         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
588         if (rc)
589                 goto out;
590         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
591         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
592 out:
593         unlock_dir(lower_dir_dentry);
594         if (!dentry->d_inode)
595                 d_drop(dentry);
596         return rc;
597 }
598
599 static int
600 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
601                 struct inode *new_dir, struct dentry *new_dentry)
602 {
603         int rc;
604         struct dentry *lower_old_dentry;
605         struct dentry *lower_new_dentry;
606         struct dentry *lower_old_dir_dentry;
607         struct dentry *lower_new_dir_dentry;
608         struct dentry *trap = NULL;
609
610         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
611         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
612         dget(lower_old_dentry);
613         dget(lower_new_dentry);
614         lower_old_dir_dentry = dget_parent(lower_old_dentry);
615         lower_new_dir_dentry = dget_parent(lower_new_dentry);
616         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
617         /* source should not be ancestor of target */
618         if (trap == lower_old_dentry) {
619                 rc = -EINVAL;
620                 goto out_lock;
621         }
622         /* target should not be ancestor of source */
623         if (trap == lower_new_dentry) {
624                 rc = -ENOTEMPTY;
625                 goto out_lock;
626         }
627         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
628                         lower_new_dir_dentry->d_inode, lower_new_dentry);
629         if (rc)
630                 goto out_lock;
631         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
632         if (new_dir != old_dir)
633                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
634 out_lock:
635         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
636         dput(lower_new_dentry->d_parent);
637         dput(lower_old_dentry->d_parent);
638         dput(lower_new_dentry);
639         dput(lower_old_dentry);
640         return rc;
641 }
642
643 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
644                                    size_t *bufsiz)
645 {
646         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
647         char *lower_buf;
648         size_t lower_bufsiz = PATH_MAX;
649         mm_segment_t old_fs;
650         int rc;
651
652         lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
653         if (!lower_buf) {
654                 rc = -ENOMEM;
655                 goto out;
656         }
657         old_fs = get_fs();
658         set_fs(get_ds());
659         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
660                                                    (char __user *)lower_buf,
661                                                    lower_bufsiz);
662         set_fs(old_fs);
663         if (rc < 0)
664                 goto out;
665         lower_bufsiz = rc;
666         rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
667                                                   lower_buf, lower_bufsiz);
668 out:
669         kfree(lower_buf);
670         return rc;
671 }
672
673 static int
674 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
675 {
676         char *kbuf;
677         size_t kbufsiz, copied;
678         int rc;
679
680         rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
681         if (rc)
682                 goto out;
683         copied = min_t(size_t, bufsiz, kbufsiz);
684         rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
685         kfree(kbuf);
686         fsstack_copy_attr_atime(dentry->d_inode,
687                                 ecryptfs_dentry_to_lower(dentry)->d_inode);
688 out:
689         return rc;
690 }
691
692 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
693 {
694         char *buf;
695         int len = PAGE_SIZE, rc;
696         mm_segment_t old_fs;
697
698         /* Released in ecryptfs_put_link(); only release here on error */
699         buf = kmalloc(len, GFP_KERNEL);
700         if (!buf) {
701                 buf = ERR_PTR(-ENOMEM);
702                 goto out;
703         }
704         old_fs = get_fs();
705         set_fs(get_ds());
706         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
707         set_fs(old_fs);
708         if (rc < 0) {
709                 kfree(buf);
710                 buf = ERR_PTR(rc);
711         } else
712                 buf[rc] = '\0';
713 out:
714         nd_set_link(nd, buf);
715         return NULL;
716 }
717
718 static void
719 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
720 {
721         char *buf = nd_get_link(nd);
722         if (!IS_ERR(buf)) {
723                 /* Free the char* */
724                 kfree(buf);
725         }
726 }
727
728 /**
729  * upper_size_to_lower_size
730  * @crypt_stat: Crypt_stat associated with file
731  * @upper_size: Size of the upper file
732  *
733  * Calculate the required size of the lower file based on the
734  * specified size of the upper file. This calculation is based on the
735  * number of headers in the underlying file and the extent size.
736  *
737  * Returns Calculated size of the lower file.
738  */
739 static loff_t
740 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
741                          loff_t upper_size)
742 {
743         loff_t lower_size;
744
745         lower_size = ecryptfs_lower_header_size(crypt_stat);
746         if (upper_size != 0) {
747                 loff_t num_extents;
748
749                 num_extents = upper_size >> crypt_stat->extent_shift;
750                 if (upper_size & ~crypt_stat->extent_mask)
751                         num_extents++;
752                 lower_size += (num_extents * crypt_stat->extent_size);
753         }
754         return lower_size;
755 }
756
757 /**
758  * truncate_upper
759  * @dentry: The ecryptfs layer dentry
760  * @ia: Address of the ecryptfs inode's attributes
761  * @lower_ia: Address of the lower inode's attributes
762  *
763  * Function to handle truncations modifying the size of the file. Note
764  * that the file sizes are interpolated. When expanding, we are simply
765  * writing strings of 0's out. When truncating, we truncate the upper
766  * inode and update the lower_ia according to the page index
767  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
768  * the caller must use lower_ia in a call to notify_change() to perform
769  * the truncation of the lower inode.
770  *
771  * Returns zero on success; non-zero otherwise
772  */
773 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
774                           struct iattr *lower_ia)
775 {
776         int rc = 0;
777         struct inode *inode = dentry->d_inode;
778         struct ecryptfs_crypt_stat *crypt_stat;
779         loff_t i_size = i_size_read(inode);
780         loff_t lower_size_before_truncate;
781         loff_t lower_size_after_truncate;
782
783         if (unlikely((ia->ia_size == i_size))) {
784                 lower_ia->ia_valid &= ~ATTR_SIZE;
785                 goto out;
786         }
787         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
788         /* Switch on growing or shrinking file */
789         if (ia->ia_size > i_size) {
790                 char zero[] = { 0x00 };
791
792                 lower_ia->ia_valid &= ~ATTR_SIZE;
793                 /* Write a single 0 at the last position of the file;
794                  * this triggers code that will fill in 0's throughout
795                  * the intermediate portion of the previous end of the
796                  * file and the new and of the file */
797                 rc = ecryptfs_write(inode, zero,
798                                     (ia->ia_size - 1), 1);
799         } else { /* ia->ia_size < i_size_read(inode) */
800                 /* We're chopping off all the pages down to the page
801                  * in which ia->ia_size is located. Fill in the end of
802                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
803                  * PAGE_CACHE_SIZE with zeros. */
804                 size_t num_zeros = (PAGE_CACHE_SIZE
805                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
806
807                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
808                         rc = simple_setsize(inode, ia->ia_size);
809                         if (rc)
810                                 goto out;
811                         lower_ia->ia_size = ia->ia_size;
812                         lower_ia->ia_valid |= ATTR_SIZE;
813                         goto out;
814                 }
815                 if (num_zeros) {
816                         char *zeros_virt;
817
818                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
819                         if (!zeros_virt) {
820                                 rc = -ENOMEM;
821                                 goto out;
822                         }
823                         rc = ecryptfs_write(inode, zeros_virt,
824                                             ia->ia_size, num_zeros);
825                         kfree(zeros_virt);
826                         if (rc) {
827                                 printk(KERN_ERR "Error attempting to zero out "
828                                        "the remainder of the end page on "
829                                        "reducing truncate; rc = [%d]\n", rc);
830                                 goto out;
831                         }
832                 }
833                 simple_setsize(inode, ia->ia_size);
834                 rc = ecryptfs_write_inode_size_to_metadata(inode);
835                 if (rc) {
836                         printk(KERN_ERR "Problem with "
837                                "ecryptfs_write_inode_size_to_metadata; "
838                                "rc = [%d]\n", rc);
839                         goto out;
840                 }
841                 /* We are reducing the size of the ecryptfs file, and need to
842                  * know if we need to reduce the size of the lower file. */
843                 lower_size_before_truncate =
844                     upper_size_to_lower_size(crypt_stat, i_size);
845                 lower_size_after_truncate =
846                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
847                 if (lower_size_after_truncate < lower_size_before_truncate) {
848                         lower_ia->ia_size = lower_size_after_truncate;
849                         lower_ia->ia_valid |= ATTR_SIZE;
850                 } else
851                         lower_ia->ia_valid &= ~ATTR_SIZE;
852         }
853 out:
854         return rc;
855 }
856
857 /**
858  * ecryptfs_truncate
859  * @dentry: The ecryptfs layer dentry
860  * @new_length: The length to expand the file to
861  *
862  * Simple function that handles the truncation of an eCryptfs inode and
863  * its corresponding lower inode.
864  *
865  * Returns zero on success; non-zero otherwise
866  */
867 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
868 {
869         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
870         struct iattr lower_ia = { .ia_valid = 0 };
871         int rc;
872
873         rc = truncate_upper(dentry, &ia, &lower_ia);
874         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
875                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
876
877                 mutex_lock(&lower_dentry->d_inode->i_mutex);
878                 rc = notify_change(lower_dentry, &lower_ia);
879                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
880         }
881         return rc;
882 }
883
884 static int
885 ecryptfs_permission(struct inode *inode, int mask)
886 {
887         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
888 }
889
890 /**
891  * ecryptfs_setattr
892  * @dentry: dentry handle to the inode to modify
893  * @ia: Structure with flags of what to change and values
894  *
895  * Updates the metadata of an inode. If the update is to the size
896  * i.e. truncation, then ecryptfs_truncate will handle the size modification
897  * of both the ecryptfs inode and the lower inode.
898  *
899  * All other metadata changes will be passed right to the lower filesystem,
900  * and we will just update our inode to look like the lower.
901  */
902 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
903 {
904         int rc = 0;
905         struct dentry *lower_dentry;
906         struct iattr lower_ia;
907         struct inode *inode;
908         struct inode *lower_inode;
909         struct ecryptfs_crypt_stat *crypt_stat;
910
911         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
912         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
913                 ecryptfs_init_crypt_stat(crypt_stat);
914         inode = dentry->d_inode;
915         lower_inode = ecryptfs_inode_to_lower(inode);
916         lower_dentry = ecryptfs_dentry_to_lower(dentry);
917         mutex_lock(&crypt_stat->cs_mutex);
918         if (S_ISDIR(dentry->d_inode->i_mode))
919                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
920         else if (S_ISREG(dentry->d_inode->i_mode)
921                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
922                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
923                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
924
925                 mount_crypt_stat = &ecryptfs_superblock_to_private(
926                         dentry->d_sb)->mount_crypt_stat;
927                 rc = ecryptfs_read_metadata(dentry);
928                 if (rc) {
929                         if (!(mount_crypt_stat->flags
930                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
931                                 rc = -EIO;
932                                 printk(KERN_WARNING "Either the lower file "
933                                        "is not in a valid eCryptfs format, "
934                                        "or the key could not be retrieved. "
935                                        "Plaintext passthrough mode is not "
936                                        "enabled; returning -EIO\n");
937                                 mutex_unlock(&crypt_stat->cs_mutex);
938                                 goto out;
939                         }
940                         rc = 0;
941                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
942                 }
943         }
944         mutex_unlock(&crypt_stat->cs_mutex);
945         memcpy(&lower_ia, ia, sizeof(lower_ia));
946         if (ia->ia_valid & ATTR_FILE)
947                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
948         if (ia->ia_valid & ATTR_SIZE) {
949                 rc = truncate_upper(dentry, ia, &lower_ia);
950                 if (rc < 0)
951                         goto out;
952         }
953
954         /*
955          * mode change is for clearing setuid/setgid bits. Allow lower fs
956          * to interpret this in its own way.
957          */
958         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
959                 lower_ia.ia_valid &= ~ATTR_MODE;
960
961         mutex_lock(&lower_dentry->d_inode->i_mutex);
962         rc = notify_change(lower_dentry, &lower_ia);
963         mutex_unlock(&lower_dentry->d_inode->i_mutex);
964 out:
965         fsstack_copy_attr_all(inode, lower_inode);
966         return rc;
967 }
968
969 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
970                           struct kstat *stat)
971 {
972         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
973         int rc = 0;
974
975         mount_crypt_stat = &ecryptfs_superblock_to_private(
976                                                 dentry->d_sb)->mount_crypt_stat;
977         generic_fillattr(dentry->d_inode, stat);
978         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
979                 char *target;
980                 size_t targetsiz;
981
982                 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
983                 if (!rc) {
984                         kfree(target);
985                         stat->size = targetsiz;
986                 }
987         }
988         return rc;
989 }
990
991 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
992                      struct kstat *stat)
993 {
994         struct kstat lower_stat;
995         int rc;
996
997         rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
998                          ecryptfs_dentry_to_lower(dentry), &lower_stat);
999         if (!rc) {
1000                 generic_fillattr(dentry->d_inode, stat);
1001                 stat->blocks = lower_stat.blocks;
1002         }
1003         return rc;
1004 }
1005
1006 int
1007 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1008                   size_t size, int flags)
1009 {
1010         int rc = 0;
1011         struct dentry *lower_dentry;
1012
1013         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1014         if (!lower_dentry->d_inode->i_op->setxattr) {
1015                 rc = -EOPNOTSUPP;
1016                 goto out;
1017         }
1018         mutex_lock(&lower_dentry->d_inode->i_mutex);
1019         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
1020                                                    size, flags);
1021         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1022 out:
1023         return rc;
1024 }
1025
1026 ssize_t
1027 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1028                         void *value, size_t size)
1029 {
1030         int rc = 0;
1031
1032         if (!lower_dentry->d_inode->i_op->getxattr) {
1033                 rc = -EOPNOTSUPP;
1034                 goto out;
1035         }
1036         mutex_lock(&lower_dentry->d_inode->i_mutex);
1037         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1038                                                    size);
1039         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1040 out:
1041         return rc;
1042 }
1043
1044 static ssize_t
1045 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1046                   size_t size)
1047 {
1048         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1049                                        value, size);
1050 }
1051
1052 static ssize_t
1053 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1054 {
1055         int rc = 0;
1056         struct dentry *lower_dentry;
1057
1058         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1059         if (!lower_dentry->d_inode->i_op->listxattr) {
1060                 rc = -EOPNOTSUPP;
1061                 goto out;
1062         }
1063         mutex_lock(&lower_dentry->d_inode->i_mutex);
1064         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1065         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1066 out:
1067         return rc;
1068 }
1069
1070 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1071 {
1072         int rc = 0;
1073         struct dentry *lower_dentry;
1074
1075         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1076         if (!lower_dentry->d_inode->i_op->removexattr) {
1077                 rc = -EOPNOTSUPP;
1078                 goto out;
1079         }
1080         mutex_lock(&lower_dentry->d_inode->i_mutex);
1081         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1082         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1083 out:
1084         return rc;
1085 }
1086
1087 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1088 {
1089         if ((ecryptfs_inode_to_lower(inode)
1090              == (struct inode *)candidate_lower_inode))
1091                 return 1;
1092         else
1093                 return 0;
1094 }
1095
1096 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1097 {
1098         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1099         return 0;
1100 }
1101
1102 const struct inode_operations ecryptfs_symlink_iops = {
1103         .readlink = ecryptfs_readlink,
1104         .follow_link = ecryptfs_follow_link,
1105         .put_link = ecryptfs_put_link,
1106         .permission = ecryptfs_permission,
1107         .setattr = ecryptfs_setattr,
1108         .getattr = ecryptfs_getattr_link,
1109         .setxattr = ecryptfs_setxattr,
1110         .getxattr = ecryptfs_getxattr,
1111         .listxattr = ecryptfs_listxattr,
1112         .removexattr = ecryptfs_removexattr
1113 };
1114
1115 const struct inode_operations ecryptfs_dir_iops = {
1116         .create = ecryptfs_create,
1117         .lookup = ecryptfs_lookup,
1118         .link = ecryptfs_link,
1119         .unlink = ecryptfs_unlink,
1120         .symlink = ecryptfs_symlink,
1121         .mkdir = ecryptfs_mkdir,
1122         .rmdir = ecryptfs_rmdir,
1123         .mknod = ecryptfs_mknod,
1124         .rename = ecryptfs_rename,
1125         .permission = ecryptfs_permission,
1126         .setattr = ecryptfs_setattr,
1127         .setxattr = ecryptfs_setxattr,
1128         .getxattr = ecryptfs_getxattr,
1129         .listxattr = ecryptfs_listxattr,
1130         .removexattr = ecryptfs_removexattr
1131 };
1132
1133 const struct inode_operations ecryptfs_main_iops = {
1134         .permission = ecryptfs_permission,
1135         .setattr = ecryptfs_setattr,
1136         .getattr = ecryptfs_getattr,
1137         .setxattr = ecryptfs_setxattr,
1138         .getxattr = ecryptfs_getxattr,
1139         .listxattr = ecryptfs_listxattr,
1140         .removexattr = ecryptfs_removexattr
1141 };