eCryptfs: remove header_extent_size
[linux-2.6] / fs / ecryptfs / inode.c
1 /**
2  * eCryptfs: Linux filesystem encryption layer
3  *
4  * Copyright (C) 1997-2004 Erez Zadok
5  * Copyright (C) 2001-2004 Stony Brook University
6  * Copyright (C) 2004-2007 International Business Machines Corp.
7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation; either version 2 of the
13  * License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23  * 02111-1307, USA.
24  */
25
26 #include <linux/file.h>
27 #include <linux/vmalloc.h>
28 #include <linux/pagemap.h>
29 #include <linux/dcache.h>
30 #include <linux/namei.h>
31 #include <linux/mount.h>
32 #include <linux/crypto.h>
33 #include <linux/fs_stack.h>
34 #include "ecryptfs_kernel.h"
35
36 static struct dentry *lock_parent(struct dentry *dentry)
37 {
38         struct dentry *dir;
39
40         dir = dget(dentry->d_parent);
41         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
42         return dir;
43 }
44
45 static void unlock_parent(struct dentry *dentry)
46 {
47         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
48         dput(dentry->d_parent);
49 }
50
51 static void unlock_dir(struct dentry *dir)
52 {
53         mutex_unlock(&dir->d_inode->i_mutex);
54         dput(dir);
55 }
56
57 /**
58  * ecryptfs_create_underlying_file
59  * @lower_dir_inode: inode of the parent in the lower fs of the new file
60  * @lower_dentry: New file's dentry in the lower fs
61  * @ecryptfs_dentry: New file's dentry in ecryptfs
62  * @mode: The mode of the new file
63  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
64  *
65  * Creates the file in the lower file system.
66  *
67  * Returns zero on success; non-zero on error condition
68  */
69 static int
70 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
71                                 struct dentry *dentry, int mode,
72                                 struct nameidata *nd)
73 {
74         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
75         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
76         struct dentry *dentry_save;
77         struct vfsmount *vfsmount_save;
78         int rc;
79
80         dentry_save = nd->dentry;
81         vfsmount_save = nd->mnt;
82         nd->dentry = lower_dentry;
83         nd->mnt = lower_mnt;
84         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
85         nd->dentry = dentry_save;
86         nd->mnt = vfsmount_save;
87         return rc;
88 }
89
90 /**
91  * ecryptfs_do_create
92  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
93  * @ecryptfs_dentry: New file's dentry in ecryptfs
94  * @mode: The mode of the new file
95  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
96  *
97  * Creates the underlying file and the eCryptfs inode which will link to
98  * it. It will also update the eCryptfs directory inode to mimic the
99  * stat of the lower directory inode.
100  *
101  * Returns zero on success; non-zero on error condition
102  */
103 static int
104 ecryptfs_do_create(struct inode *directory_inode,
105                    struct dentry *ecryptfs_dentry, int mode,
106                    struct nameidata *nd)
107 {
108         int rc;
109         struct dentry *lower_dentry;
110         struct dentry *lower_dir_dentry;
111
112         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
113         lower_dir_dentry = lock_parent(lower_dentry);
114         if (unlikely(IS_ERR(lower_dir_dentry))) {
115                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
116                                 "dentry\n");
117                 rc = PTR_ERR(lower_dir_dentry);
118                 goto out;
119         }
120         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
121                                              ecryptfs_dentry, mode, nd);
122         if (unlikely(rc)) {
123                 ecryptfs_printk(KERN_ERR,
124                                 "Failure to create underlying file\n");
125                 goto out_lock;
126         }
127         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
128                                 directory_inode->i_sb, 0);
129         if (rc) {
130                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
131                 goto out_lock;
132         }
133         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
134         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
135 out_lock:
136         unlock_dir(lower_dir_dentry);
137 out:
138         return rc;
139 }
140
141 /**
142  * grow_file
143  * @ecryptfs_dentry: the ecryptfs dentry
144  * @lower_file: The lower file
145  * @inode: The ecryptfs inode
146  * @lower_inode: The lower inode
147  *
148  * This is the code which will grow the file to its correct size.
149  */
150 static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
151                      struct inode *inode, struct inode *lower_inode)
152 {
153         int rc = 0;
154         struct file fake_file;
155         struct ecryptfs_file_info tmp_file_info;
156
157         memset(&fake_file, 0, sizeof(fake_file));
158         fake_file.f_path.dentry = ecryptfs_dentry;
159         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
160         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
161         ecryptfs_set_file_lower(&fake_file, lower_file);
162         rc = ecryptfs_fill_zeros(&fake_file, 1);
163         if (rc) {
164                 ecryptfs_inode_to_private(inode)->crypt_stat.flags |=
165                         ECRYPTFS_SECURITY_WARNING;
166                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
167                                 "in file; rc = [%d]\n", rc);
168                 goto out;
169         }
170         i_size_write(inode, 0);
171         rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode,
172                         inode, ecryptfs_dentry,
173                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
174         ecryptfs_inode_to_private(inode)->crypt_stat.flags |= ECRYPTFS_NEW_FILE;
175 out:
176         return rc;
177 }
178
179 /**
180  * ecryptfs_initialize_file
181  *
182  * Cause the file to be changed from a basic empty file to an ecryptfs
183  * file with a header and first data page.
184  *
185  * Returns zero on success
186  */
187 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
188 {
189         int rc = 0;
190         int lower_flags;
191         struct ecryptfs_crypt_stat *crypt_stat;
192         struct dentry *lower_dentry;
193         struct file *lower_file;
194         struct inode *inode, *lower_inode;
195         struct vfsmount *lower_mnt;
196
197         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
198         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
199                         lower_dentry->d_name.name);
200         inode = ecryptfs_dentry->d_inode;
201         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
202         lower_flags = ((O_CREAT | O_TRUNC) & O_ACCMODE) | O_RDWR;
203         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
204         /* Corresponding fput() at end of this function */
205         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
206                                            lower_flags))) {
207                 ecryptfs_printk(KERN_ERR,
208                                 "Error opening dentry; rc = [%i]\n", rc);
209                 goto out;
210         }
211         lower_inode = lower_dentry->d_inode;
212         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
213                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
214                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
215                 goto out_fput;
216         }
217         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
218         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
219         rc = ecryptfs_new_file_context(ecryptfs_dentry);
220         if (rc) {
221                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
222                                 "context\n");
223                 goto out_fput;
224         }
225         rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
226         if (rc) {
227                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
228                 goto out_fput;
229         }
230         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
231 out_fput:
232         if ((rc = ecryptfs_close_lower_file(lower_file)))
233                 printk(KERN_ERR "Error closing lower_file\n");
234 out:
235         return rc;
236 }
237
238 /**
239  * ecryptfs_create
240  * @dir: The inode of the directory in which to create the file.
241  * @dentry: The eCryptfs dentry
242  * @mode: The mode of the new file.
243  * @nd: nameidata
244  *
245  * Creates a new file.
246  *
247  * Returns zero on success; non-zero on error condition
248  */
249 static int
250 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
251                 int mode, struct nameidata *nd)
252 {
253         int rc;
254
255         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
256         if (unlikely(rc)) {
257                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
258                                 "lower filesystem\n");
259                 goto out;
260         }
261         /* At this point, a file exists on "disk"; we need to make sure
262          * that this on disk file is prepared to be an ecryptfs file */
263         rc = ecryptfs_initialize_file(ecryptfs_dentry);
264 out:
265         return rc;
266 }
267
268 /**
269  * ecryptfs_lookup
270  * @dir: inode
271  * @dentry: The dentry
272  * @nd: nameidata, may be NULL
273  *
274  * Find a file on disk. If the file does not exist, then we'll add it to the
275  * dentry cache and continue on to read it from the disk.
276  */
277 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
278                                       struct nameidata *nd)
279 {
280         int rc = 0;
281         struct dentry *lower_dir_dentry;
282         struct dentry *lower_dentry;
283         struct vfsmount *lower_mnt;
284         char *encoded_name;
285         int encoded_namelen;
286         struct ecryptfs_crypt_stat *crypt_stat = NULL;
287         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
288         char *page_virt = NULL;
289         struct inode *lower_inode;
290         u64 file_size;
291
292         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
293         dentry->d_op = &ecryptfs_dops;
294         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
295             || (dentry->d_name.len == 2
296                 && !strcmp(dentry->d_name.name, ".."))) {
297                 d_drop(dentry);
298                 goto out;
299         }
300         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
301                                                    dentry->d_name.name,
302                                                    dentry->d_name.len,
303                                                    &encoded_name);
304         if (encoded_namelen < 0) {
305                 rc = encoded_namelen;
306                 d_drop(dentry);
307                 goto out;
308         }
309         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
310                         "= [%d]\n", encoded_name, encoded_namelen);
311         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
312                                       encoded_namelen - 1);
313         kfree(encoded_name);
314         if (IS_ERR(lower_dentry)) {
315                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
316                 rc = PTR_ERR(lower_dentry);
317                 d_drop(dentry);
318                 goto out;
319         }
320         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
321         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
322                 "d_name.name = [%s]\n", lower_dentry,
323                 lower_dentry->d_name.name);
324         lower_inode = lower_dentry->d_inode;
325         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
326         BUG_ON(!atomic_read(&lower_dentry->d_count));
327         ecryptfs_set_dentry_private(dentry,
328                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
329                                                      GFP_KERNEL));
330         if (!ecryptfs_dentry_to_private(dentry)) {
331                 rc = -ENOMEM;
332                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
333                                 "to allocate ecryptfs_dentry_info struct\n");
334                 goto out_dput;
335         }
336         ecryptfs_set_dentry_lower(dentry, lower_dentry);
337         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
338         if (!lower_dentry->d_inode) {
339                 /* We want to add because we couldn't find in lower */
340                 d_add(dentry, NULL);
341                 goto out;
342         }
343         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
344         if (rc) {
345                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
346                 goto out_dput;
347         }
348         if (S_ISDIR(lower_inode->i_mode)) {
349                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
350                 goto out;
351         }
352         if (S_ISLNK(lower_inode->i_mode)) {
353                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
354                 goto out;
355         }
356         if (special_file(lower_inode->i_mode)) {
357                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
358                 goto out;
359         }
360         if (!nd) {
361                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
362                                 "as we *think* we are about to unlink\n");
363                 goto out;
364         }
365         /* Released in this function */
366         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
367                                       GFP_USER);
368         if (!page_virt) {
369                 rc = -ENOMEM;
370                 ecryptfs_printk(KERN_ERR,
371                                 "Cannot ecryptfs_kmalloc a page\n");
372                 goto out_dput;
373         }
374         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
375         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
376                 ecryptfs_set_default_sizes(crypt_stat);
377         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
378                                                       nd->mnt);
379         if (rc) {
380                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
381                 if (rc) {
382                         printk(KERN_DEBUG "Valid metadata not found in header "
383                                "region or xattr region; treating file as "
384                                "unencrypted\n");
385                         rc = 0;
386                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
387                         goto out;
388                 }
389                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
390         }
391         mount_crypt_stat = &ecryptfs_superblock_to_private(
392                 dentry->d_sb)->mount_crypt_stat;
393         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
394                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
395                         file_size = ((crypt_stat->extent_size
396                                       * crypt_stat->num_header_extents_at_front)
397                                      + i_size_read(lower_dentry->d_inode));
398                 else
399                         file_size = i_size_read(lower_dentry->d_inode);
400         } else {
401                 memcpy(&file_size, page_virt, sizeof(file_size));
402                 file_size = be64_to_cpu(file_size);
403         }
404         i_size_write(dentry->d_inode, (loff_t)file_size);
405         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
406         goto out;
407
408 out_dput:
409         dput(lower_dentry);
410         d_drop(dentry);
411 out:
412         return ERR_PTR(rc);
413 }
414
415 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
416                          struct dentry *new_dentry)
417 {
418         struct dentry *lower_old_dentry;
419         struct dentry *lower_new_dentry;
420         struct dentry *lower_dir_dentry;
421         u64 file_size_save;
422         int rc;
423
424         file_size_save = i_size_read(old_dentry->d_inode);
425         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
426         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
427         dget(lower_old_dentry);
428         dget(lower_new_dentry);
429         lower_dir_dentry = lock_parent(lower_new_dentry);
430         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
431                       lower_new_dentry);
432         if (rc || !lower_new_dentry->d_inode)
433                 goto out_lock;
434         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
435         if (rc)
436                 goto out_lock;
437         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
438         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
439         old_dentry->d_inode->i_nlink =
440                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
441         i_size_write(new_dentry->d_inode, file_size_save);
442 out_lock:
443         unlock_dir(lower_dir_dentry);
444         dput(lower_new_dentry);
445         dput(lower_old_dentry);
446         d_drop(lower_old_dentry);
447         d_drop(new_dentry);
448         d_drop(old_dentry);
449         return rc;
450 }
451
452 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
453 {
454         int rc = 0;
455         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
456         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
457
458         lock_parent(lower_dentry);
459         rc = vfs_unlink(lower_dir_inode, lower_dentry);
460         if (rc) {
461                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
462                 goto out_unlock;
463         }
464         fsstack_copy_attr_times(dir, lower_dir_inode);
465         dentry->d_inode->i_nlink =
466                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
467         dentry->d_inode->i_ctime = dir->i_ctime;
468 out_unlock:
469         unlock_parent(lower_dentry);
470         return rc;
471 }
472
473 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
474                             const char *symname)
475 {
476         int rc;
477         struct dentry *lower_dentry;
478         struct dentry *lower_dir_dentry;
479         umode_t mode;
480         char *encoded_symname;
481         int encoded_symlen;
482         struct ecryptfs_crypt_stat *crypt_stat = NULL;
483
484         lower_dentry = ecryptfs_dentry_to_lower(dentry);
485         dget(lower_dentry);
486         lower_dir_dentry = lock_parent(lower_dentry);
487         mode = S_IALLUGO;
488         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
489                                                   strlen(symname),
490                                                   &encoded_symname);
491         if (encoded_symlen < 0) {
492                 rc = encoded_symlen;
493                 goto out_lock;
494         }
495         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
496                          encoded_symname, mode);
497         kfree(encoded_symname);
498         if (rc || !lower_dentry->d_inode)
499                 goto out_lock;
500         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
501         if (rc)
502                 goto out_lock;
503         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
504         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
505 out_lock:
506         unlock_dir(lower_dir_dentry);
507         dput(lower_dentry);
508         if (!dentry->d_inode)
509                 d_drop(dentry);
510         return rc;
511 }
512
513 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
514 {
515         int rc;
516         struct dentry *lower_dentry;
517         struct dentry *lower_dir_dentry;
518
519         lower_dentry = ecryptfs_dentry_to_lower(dentry);
520         lower_dir_dentry = lock_parent(lower_dentry);
521         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
522         if (rc || !lower_dentry->d_inode)
523                 goto out;
524         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
525         if (rc)
526                 goto out;
527         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
528         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
529         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
530 out:
531         unlock_dir(lower_dir_dentry);
532         if (!dentry->d_inode)
533                 d_drop(dentry);
534         return rc;
535 }
536
537 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
538 {
539         struct dentry *lower_dentry;
540         struct dentry *lower_dir_dentry;
541         int rc;
542
543         lower_dentry = ecryptfs_dentry_to_lower(dentry);
544         dget(dentry);
545         lower_dir_dentry = lock_parent(lower_dentry);
546         dget(lower_dentry);
547         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
548         dput(lower_dentry);
549         if (!rc)
550                 d_delete(lower_dentry);
551         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
552         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
553         unlock_dir(lower_dir_dentry);
554         if (!rc)
555                 d_drop(dentry);
556         dput(dentry);
557         return rc;
558 }
559
560 static int
561 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
562 {
563         int rc;
564         struct dentry *lower_dentry;
565         struct dentry *lower_dir_dentry;
566
567         lower_dentry = ecryptfs_dentry_to_lower(dentry);
568         lower_dir_dentry = lock_parent(lower_dentry);
569         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
570         if (rc || !lower_dentry->d_inode)
571                 goto out;
572         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
573         if (rc)
574                 goto out;
575         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
576         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
577 out:
578         unlock_dir(lower_dir_dentry);
579         if (!dentry->d_inode)
580                 d_drop(dentry);
581         return rc;
582 }
583
584 static int
585 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
586                 struct inode *new_dir, struct dentry *new_dentry)
587 {
588         int rc;
589         struct dentry *lower_old_dentry;
590         struct dentry *lower_new_dentry;
591         struct dentry *lower_old_dir_dentry;
592         struct dentry *lower_new_dir_dentry;
593
594         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
595         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
596         dget(lower_old_dentry);
597         dget(lower_new_dentry);
598         lower_old_dir_dentry = dget_parent(lower_old_dentry);
599         lower_new_dir_dentry = dget_parent(lower_new_dentry);
600         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
601         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
602                         lower_new_dir_dentry->d_inode, lower_new_dentry);
603         if (rc)
604                 goto out_lock;
605         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
606         if (new_dir != old_dir)
607                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
608 out_lock:
609         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
610         dput(lower_new_dentry->d_parent);
611         dput(lower_old_dentry->d_parent);
612         dput(lower_new_dentry);
613         dput(lower_old_dentry);
614         return rc;
615 }
616
617 static int
618 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
619 {
620         int rc;
621         struct dentry *lower_dentry;
622         char *decoded_name;
623         char *lower_buf;
624         mm_segment_t old_fs;
625         struct ecryptfs_crypt_stat *crypt_stat;
626
627         lower_dentry = ecryptfs_dentry_to_lower(dentry);
628         if (!lower_dentry->d_inode->i_op ||
629             !lower_dentry->d_inode->i_op->readlink) {
630                 rc = -EINVAL;
631                 goto out;
632         }
633         /* Released in this function */
634         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
635         if (lower_buf == NULL) {
636                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
637                 rc = -ENOMEM;
638                 goto out;
639         }
640         old_fs = get_fs();
641         set_fs(get_ds());
642         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
643                         "lower_dentry->d_name.name = [%s]\n",
644                         lower_dentry->d_name.name);
645         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
646                                                    (char __user *)lower_buf,
647                                                    bufsiz);
648         set_fs(old_fs);
649         if (rc >= 0) {
650                 crypt_stat = NULL;
651                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
652                                               &decoded_name);
653                 if (rc == -ENOMEM)
654                         goto out_free_lower_buf;
655                 if (rc > 0) {
656                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
657                                         "to userspace: [%*s]\n", rc,
658                                         decoded_name);
659                         if (copy_to_user(buf, decoded_name, rc))
660                                 rc = -EFAULT;
661                 }
662                 kfree(decoded_name);
663                 fsstack_copy_attr_atime(dentry->d_inode,
664                                         lower_dentry->d_inode);
665         }
666 out_free_lower_buf:
667         kfree(lower_buf);
668 out:
669         return rc;
670 }
671
672 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
673 {
674         char *buf;
675         int len = PAGE_SIZE, rc;
676         mm_segment_t old_fs;
677
678         /* Released in ecryptfs_put_link(); only release here on error */
679         buf = kmalloc(len, GFP_KERNEL);
680         if (!buf) {
681                 rc = -ENOMEM;
682                 goto out;
683         }
684         old_fs = get_fs();
685         set_fs(get_ds());
686         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
687                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
688         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
689         buf[rc] = '\0';
690         set_fs(old_fs);
691         if (rc < 0)
692                 goto out_free;
693         rc = 0;
694         nd_set_link(nd, buf);
695         goto out;
696 out_free:
697         kfree(buf);
698 out:
699         return ERR_PTR(rc);
700 }
701
702 static void
703 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
704 {
705         /* Free the char* */
706         kfree(nd_get_link(nd));
707 }
708
709 /**
710  * upper_size_to_lower_size
711  * @crypt_stat: Crypt_stat associated with file
712  * @upper_size: Size of the upper file
713  *
714  * Calculate the requried size of the lower file based on the
715  * specified size of the upper file. This calculation is based on the
716  * number of headers in the underlying file and the extent size.
717  *
718  * Returns Calculated size of the lower file.
719  */
720 static loff_t
721 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
722                          loff_t upper_size)
723 {
724         loff_t lower_size;
725
726         lower_size = (crypt_stat->extent_size
727                       * crypt_stat->num_header_extents_at_front);
728         if (upper_size != 0) {
729                 loff_t num_extents;
730
731                 num_extents = upper_size >> crypt_stat->extent_shift;
732                 if (upper_size & ~crypt_stat->extent_mask)
733                         num_extents++;
734                 lower_size += (num_extents * crypt_stat->extent_size);
735         }
736         return lower_size;
737 }
738
739 /**
740  * ecryptfs_truncate
741  * @dentry: The ecryptfs layer dentry
742  * @new_length: The length to expand the file to
743  *
744  * Function to handle truncations modifying the size of the file. Note
745  * that the file sizes are interpolated. When expanding, we are simply
746  * writing strings of 0's out. When truncating, we need to modify the
747  * underlying file size according to the page index interpolations.
748  *
749  * Returns zero on success; non-zero otherwise
750  */
751 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
752 {
753         int rc = 0;
754         struct inode *inode = dentry->d_inode;
755         struct dentry *lower_dentry;
756         struct vfsmount *lower_mnt;
757         struct file fake_ecryptfs_file, *lower_file = NULL;
758         struct ecryptfs_crypt_stat *crypt_stat;
759         loff_t i_size = i_size_read(inode);
760         loff_t lower_size_before_truncate;
761         loff_t lower_size_after_truncate;
762
763         if (unlikely((new_length == i_size)))
764                 goto out;
765         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
766         /* Set up a fake ecryptfs file, this is used to interface with
767          * the file in the underlying filesystem so that the
768          * truncation has an effect there as well. */
769         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
770         fake_ecryptfs_file.f_path.dentry = dentry;
771         /* Released at out_free: label */
772         ecryptfs_set_file_private(&fake_ecryptfs_file,
773                                   kmem_cache_alloc(ecryptfs_file_info_cache,
774                                                    GFP_KERNEL));
775         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
776                 rc = -ENOMEM;
777                 goto out;
778         }
779         lower_dentry = ecryptfs_dentry_to_lower(dentry);
780         /* This dget & mntget is released through fput at out_fput: */
781         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
782         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
783                                            O_RDWR))) {
784                 ecryptfs_printk(KERN_ERR,
785                                 "Error opening dentry; rc = [%i]\n", rc);
786                 goto out_free;
787         }
788         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
789         /* Switch on growing or shrinking file */
790         if (new_length > i_size) {
791                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
792                 if (rc) {
793                         ecryptfs_printk(KERN_ERR,
794                                         "Problem with fill_zeros\n");
795                         goto out_fput;
796                 }
797                 i_size_write(inode, new_length);
798                 rc = ecryptfs_write_inode_size_to_metadata(
799                         lower_file, lower_dentry->d_inode, inode, dentry,
800                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
801                 if (rc) {
802                         printk(KERN_ERR "Problem with "
803                                "ecryptfs_write_inode_size_to_metadata; "
804                                "rc = [%d]\n", rc);
805                         goto out_fput;
806                 }
807         } else { /* new_length < i_size_read(inode) */
808                 pgoff_t index = 0;
809                 int end_pos_in_page = -1;
810
811                 if (new_length != 0) {
812                         index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
813                         end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
814                 }
815                 if (end_pos_in_page != (PAGE_CACHE_SIZE - 1)) {
816                         if ((rc = ecryptfs_write_zeros(&fake_ecryptfs_file,
817                                                        index,
818                                                        (end_pos_in_page + 1),
819                                                        ((PAGE_CACHE_SIZE - 1)
820                                                         - end_pos_in_page)))) {
821                                 printk(KERN_ERR "Error attempting to zero out "
822                                        "the remainder of the end page on "
823                                        "reducing truncate; rc = [%d]\n", rc);
824                                 goto out_fput;
825                         }
826                 }
827                 vmtruncate(inode, new_length);
828                 rc = ecryptfs_write_inode_size_to_metadata(
829                         lower_file, lower_dentry->d_inode, inode, dentry,
830                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
831                 if (rc) {
832                         printk(KERN_ERR "Problem with "
833                                "ecryptfs_write_inode_size_to_metadata; "
834                                "rc = [%d]\n", rc);
835                         goto out_fput;
836                 }
837                 /* We are reducing the size of the ecryptfs file, and need to
838                  * know if we need to reduce the size of the lower file. */
839                 lower_size_before_truncate =
840                     upper_size_to_lower_size(crypt_stat, i_size);
841                 lower_size_after_truncate =
842                     upper_size_to_lower_size(crypt_stat, new_length);
843                 if (lower_size_after_truncate < lower_size_before_truncate)
844                         vmtruncate(lower_dentry->d_inode,
845                                    lower_size_after_truncate);
846         }
847         /* Update the access times */
848         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
849                 = CURRENT_TIME;
850         mark_inode_dirty_sync(inode);
851 out_fput:
852         if ((rc = ecryptfs_close_lower_file(lower_file)))
853                 printk(KERN_ERR "Error closing lower_file\n");
854 out_free:
855         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
856                 kmem_cache_free(ecryptfs_file_info_cache,
857                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
858 out:
859         return rc;
860 }
861
862 static int
863 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
864 {
865         int rc;
866
867         if (nd) {
868                 struct vfsmount *vfsmnt_save = nd->mnt;
869                 struct dentry *dentry_save = nd->dentry;
870
871                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
872                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
873                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
874                 nd->mnt = vfsmnt_save;
875                 nd->dentry = dentry_save;
876         } else
877                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
878         return rc;
879 }
880
881 /**
882  * ecryptfs_setattr
883  * @dentry: dentry handle to the inode to modify
884  * @ia: Structure with flags of what to change and values
885  *
886  * Updates the metadata of an inode. If the update is to the size
887  * i.e. truncation, then ecryptfs_truncate will handle the size modification
888  * of both the ecryptfs inode and the lower inode.
889  *
890  * All other metadata changes will be passed right to the lower filesystem,
891  * and we will just update our inode to look like the lower.
892  */
893 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
894 {
895         int rc = 0;
896         struct dentry *lower_dentry;
897         struct inode *inode;
898         struct inode *lower_inode;
899         struct ecryptfs_crypt_stat *crypt_stat;
900
901         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
902         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
903                 ecryptfs_init_crypt_stat(crypt_stat);
904         inode = dentry->d_inode;
905         lower_inode = ecryptfs_inode_to_lower(inode);
906         lower_dentry = ecryptfs_dentry_to_lower(dentry);
907         mutex_lock(&crypt_stat->cs_mutex);
908         if (S_ISDIR(dentry->d_inode->i_mode))
909                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
910         else if (S_ISREG(dentry->d_inode->i_mode)
911                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
912                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
913                 struct vfsmount *lower_mnt;
914                 struct file *lower_file = NULL;
915                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
916                 int lower_flags;
917
918                 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
919                 lower_flags = O_RDONLY;
920                 if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
921                                                    lower_mnt, lower_flags))) {
922                         printk(KERN_ERR
923                                "Error opening lower file; rc = [%d]\n", rc);
924                         mutex_unlock(&crypt_stat->cs_mutex);
925                         goto out;
926                 }
927                 mount_crypt_stat = &ecryptfs_superblock_to_private(
928                         dentry->d_sb)->mount_crypt_stat;
929                 if ((rc = ecryptfs_read_metadata(dentry, lower_file))) {
930                         if (!(mount_crypt_stat->flags
931                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
932                                 rc = -EIO;
933                                 printk(KERN_WARNING "Attempt to read file that "
934                                        "is not in a valid eCryptfs format, "
935                                        "and plaintext passthrough mode is not "
936                                        "enabled; returning -EIO\n");
937
938                                 mutex_unlock(&crypt_stat->cs_mutex);
939                                 fput(lower_file);
940                                 goto out;
941                         }
942                         rc = 0;
943                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
944                         mutex_unlock(&crypt_stat->cs_mutex);
945                         fput(lower_file);
946                         goto out;
947                 }
948                 fput(lower_file);
949         }
950         mutex_unlock(&crypt_stat->cs_mutex);
951         if (ia->ia_valid & ATTR_SIZE) {
952                 ecryptfs_printk(KERN_DEBUG,
953                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
954                                 ia->ia_valid, ATTR_SIZE);
955                 rc = ecryptfs_truncate(dentry, ia->ia_size);
956                 /* ecryptfs_truncate handles resizing of the lower file */
957                 ia->ia_valid &= ~ATTR_SIZE;
958                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
959                                 ia->ia_valid);
960                 if (rc < 0)
961                         goto out;
962         }
963         rc = notify_change(lower_dentry, ia);
964 out:
965         fsstack_copy_attr_all(inode, lower_inode, NULL);
966         return rc;
967 }
968
969 int
970 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
971                   size_t size, int flags)
972 {
973         int rc = 0;
974         struct dentry *lower_dentry;
975
976         lower_dentry = ecryptfs_dentry_to_lower(dentry);
977         if (!lower_dentry->d_inode->i_op->setxattr) {
978                 rc = -ENOSYS;
979                 goto out;
980         }
981         mutex_lock(&lower_dentry->d_inode->i_mutex);
982         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
983                                                    size, flags);
984         mutex_unlock(&lower_dentry->d_inode->i_mutex);
985 out:
986         return rc;
987 }
988
989 ssize_t
990 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
991                   size_t size)
992 {
993         int rc = 0;
994         struct dentry *lower_dentry;
995
996         lower_dentry = ecryptfs_dentry_to_lower(dentry);
997         if (!lower_dentry->d_inode->i_op->getxattr) {
998                 rc = -ENOSYS;
999                 goto out;
1000         }
1001         mutex_lock(&lower_dentry->d_inode->i_mutex);
1002         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1003                                                    size);
1004         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1005 out:
1006         return rc;
1007 }
1008
1009 static ssize_t
1010 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1011 {
1012         int rc = 0;
1013         struct dentry *lower_dentry;
1014
1015         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1016         if (!lower_dentry->d_inode->i_op->listxattr) {
1017                 rc = -ENOSYS;
1018                 goto out;
1019         }
1020         mutex_lock(&lower_dentry->d_inode->i_mutex);
1021         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1022         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1023 out:
1024         return rc;
1025 }
1026
1027 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1028 {
1029         int rc = 0;
1030         struct dentry *lower_dentry;
1031
1032         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1033         if (!lower_dentry->d_inode->i_op->removexattr) {
1034                 rc = -ENOSYS;
1035                 goto out;
1036         }
1037         mutex_lock(&lower_dentry->d_inode->i_mutex);
1038         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1039         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1040 out:
1041         return rc;
1042 }
1043
1044 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1045 {
1046         if ((ecryptfs_inode_to_lower(inode)
1047              == (struct inode *)candidate_lower_inode))
1048                 return 1;
1049         else
1050                 return 0;
1051 }
1052
1053 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1054 {
1055         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1056         return 0;
1057 }
1058
1059 const struct inode_operations ecryptfs_symlink_iops = {
1060         .readlink = ecryptfs_readlink,
1061         .follow_link = ecryptfs_follow_link,
1062         .put_link = ecryptfs_put_link,
1063         .permission = ecryptfs_permission,
1064         .setattr = ecryptfs_setattr,
1065         .setxattr = ecryptfs_setxattr,
1066         .getxattr = ecryptfs_getxattr,
1067         .listxattr = ecryptfs_listxattr,
1068         .removexattr = ecryptfs_removexattr
1069 };
1070
1071 const struct inode_operations ecryptfs_dir_iops = {
1072         .create = ecryptfs_create,
1073         .lookup = ecryptfs_lookup,
1074         .link = ecryptfs_link,
1075         .unlink = ecryptfs_unlink,
1076         .symlink = ecryptfs_symlink,
1077         .mkdir = ecryptfs_mkdir,
1078         .rmdir = ecryptfs_rmdir,
1079         .mknod = ecryptfs_mknod,
1080         .rename = ecryptfs_rename,
1081         .permission = ecryptfs_permission,
1082         .setattr = ecryptfs_setattr,
1083         .setxattr = ecryptfs_setxattr,
1084         .getxattr = ecryptfs_getxattr,
1085         .listxattr = ecryptfs_listxattr,
1086         .removexattr = ecryptfs_removexattr
1087 };
1088
1089 const struct inode_operations ecryptfs_main_iops = {
1090         .permission = ecryptfs_permission,
1091         .setattr = ecryptfs_setattr,
1092         .setxattr = ecryptfs_setxattr,
1093         .getxattr = ecryptfs_getxattr,
1094         .listxattr = ecryptfs_listxattr,
1095         .removexattr = ecryptfs_removexattr
1096 };