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