Pull acpi-debug into release branch
[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 (!nd) {
357                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
358                                 "as we *think* we are about to unlink\n");
359                 goto out;
360         }
361         /* Released in this function */
362         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
363                                       GFP_USER);
364         if (!page_virt) {
365                 rc = -ENOMEM;
366                 ecryptfs_printk(KERN_ERR,
367                                 "Cannot ecryptfs_kmalloc a page\n");
368                 goto out_dput;
369         }
370         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
371         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
372                 ecryptfs_set_default_sizes(crypt_stat);
373         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
374                                                       nd->mnt);
375         if (rc) {
376                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
377                 if (rc) {
378                         printk(KERN_DEBUG "Valid metadata not found in header "
379                                "region or xattr region; treating file as "
380                                "unencrypted\n");
381                         rc = 0;
382                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
383                         goto out;
384                 }
385                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
386         }
387         mount_crypt_stat = &ecryptfs_superblock_to_private(
388                 dentry->d_sb)->mount_crypt_stat;
389         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
390                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
391                         file_size = (crypt_stat->header_extent_size
392                                      + i_size_read(lower_dentry->d_inode));
393                 else
394                         file_size = i_size_read(lower_dentry->d_inode);
395         } else {
396                 memcpy(&file_size, page_virt, sizeof(file_size));
397                 file_size = be64_to_cpu(file_size);
398         }
399         i_size_write(dentry->d_inode, (loff_t)file_size);
400         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
401         goto out;
402
403 out_dput:
404         dput(lower_dentry);
405         d_drop(dentry);
406 out:
407         return ERR_PTR(rc);
408 }
409
410 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
411                          struct dentry *new_dentry)
412 {
413         struct dentry *lower_old_dentry;
414         struct dentry *lower_new_dentry;
415         struct dentry *lower_dir_dentry;
416         u64 file_size_save;
417         int rc;
418
419         file_size_save = i_size_read(old_dentry->d_inode);
420         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
421         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
422         dget(lower_old_dentry);
423         dget(lower_new_dentry);
424         lower_dir_dentry = lock_parent(lower_new_dentry);
425         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
426                       lower_new_dentry);
427         if (rc || !lower_new_dentry->d_inode)
428                 goto out_lock;
429         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
430         if (rc)
431                 goto out_lock;
432         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
433         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
434         old_dentry->d_inode->i_nlink =
435                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
436         i_size_write(new_dentry->d_inode, file_size_save);
437 out_lock:
438         unlock_dir(lower_dir_dentry);
439         dput(lower_new_dentry);
440         dput(lower_old_dentry);
441         d_drop(lower_old_dentry);
442         d_drop(new_dentry);
443         d_drop(old_dentry);
444         return rc;
445 }
446
447 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
448 {
449         int rc = 0;
450         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
451         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
452
453         lock_parent(lower_dentry);
454         rc = vfs_unlink(lower_dir_inode, lower_dentry);
455         if (rc) {
456                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
457                 goto out_unlock;
458         }
459         fsstack_copy_attr_times(dir, lower_dir_inode);
460         dentry->d_inode->i_nlink =
461                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
462         dentry->d_inode->i_ctime = dir->i_ctime;
463 out_unlock:
464         unlock_parent(lower_dentry);
465         return rc;
466 }
467
468 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
469                             const char *symname)
470 {
471         int rc;
472         struct dentry *lower_dentry;
473         struct dentry *lower_dir_dentry;
474         umode_t mode;
475         char *encoded_symname;
476         int encoded_symlen;
477         struct ecryptfs_crypt_stat *crypt_stat = NULL;
478
479         lower_dentry = ecryptfs_dentry_to_lower(dentry);
480         dget(lower_dentry);
481         lower_dir_dentry = lock_parent(lower_dentry);
482         mode = S_IALLUGO;
483         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
484                                                   strlen(symname),
485                                                   &encoded_symname);
486         if (encoded_symlen < 0) {
487                 rc = encoded_symlen;
488                 goto out_lock;
489         }
490         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
491                          encoded_symname, mode);
492         kfree(encoded_symname);
493         if (rc || !lower_dentry->d_inode)
494                 goto out_lock;
495         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
496         if (rc)
497                 goto out_lock;
498         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
499         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
500 out_lock:
501         unlock_dir(lower_dir_dentry);
502         dput(lower_dentry);
503         if (!dentry->d_inode)
504                 d_drop(dentry);
505         return rc;
506 }
507
508 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
509 {
510         int rc;
511         struct dentry *lower_dentry;
512         struct dentry *lower_dir_dentry;
513
514         lower_dentry = ecryptfs_dentry_to_lower(dentry);
515         lower_dir_dentry = lock_parent(lower_dentry);
516         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
517         if (rc || !lower_dentry->d_inode)
518                 goto out;
519         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
520         if (rc)
521                 goto out;
522         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
523         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
524         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
525 out:
526         unlock_dir(lower_dir_dentry);
527         if (!dentry->d_inode)
528                 d_drop(dentry);
529         return rc;
530 }
531
532 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
533 {
534         struct dentry *lower_dentry;
535         struct dentry *lower_dir_dentry;
536         int rc;
537
538         lower_dentry = ecryptfs_dentry_to_lower(dentry);
539         dget(dentry);
540         lower_dir_dentry = lock_parent(lower_dentry);
541         dget(lower_dentry);
542         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
543         dput(lower_dentry);
544         if (!rc)
545                 d_delete(lower_dentry);
546         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
547         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
548         unlock_dir(lower_dir_dentry);
549         if (!rc)
550                 d_drop(dentry);
551         dput(dentry);
552         return rc;
553 }
554
555 static int
556 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
557 {
558         int rc;
559         struct dentry *lower_dentry;
560         struct dentry *lower_dir_dentry;
561
562         lower_dentry = ecryptfs_dentry_to_lower(dentry);
563         lower_dir_dentry = lock_parent(lower_dentry);
564         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
565         if (rc || !lower_dentry->d_inode)
566                 goto out;
567         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
568         if (rc)
569                 goto out;
570         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
571         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
572 out:
573         unlock_dir(lower_dir_dentry);
574         if (!dentry->d_inode)
575                 d_drop(dentry);
576         return rc;
577 }
578
579 static int
580 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
581                 struct inode *new_dir, struct dentry *new_dentry)
582 {
583         int rc;
584         struct dentry *lower_old_dentry;
585         struct dentry *lower_new_dentry;
586         struct dentry *lower_old_dir_dentry;
587         struct dentry *lower_new_dir_dentry;
588
589         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
590         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
591         dget(lower_old_dentry);
592         dget(lower_new_dentry);
593         lower_old_dir_dentry = dget_parent(lower_old_dentry);
594         lower_new_dir_dentry = dget_parent(lower_new_dentry);
595         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
596         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
597                         lower_new_dir_dentry->d_inode, lower_new_dentry);
598         if (rc)
599                 goto out_lock;
600         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
601         if (new_dir != old_dir)
602                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
603 out_lock:
604         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
605         dput(lower_new_dentry->d_parent);
606         dput(lower_old_dentry->d_parent);
607         dput(lower_new_dentry);
608         dput(lower_old_dentry);
609         return rc;
610 }
611
612 static int
613 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
614 {
615         int rc;
616         struct dentry *lower_dentry;
617         char *decoded_name;
618         char *lower_buf;
619         mm_segment_t old_fs;
620         struct ecryptfs_crypt_stat *crypt_stat;
621
622         lower_dentry = ecryptfs_dentry_to_lower(dentry);
623         if (!lower_dentry->d_inode->i_op ||
624             !lower_dentry->d_inode->i_op->readlink) {
625                 rc = -EINVAL;
626                 goto out;
627         }
628         /* Released in this function */
629         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
630         if (lower_buf == NULL) {
631                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
632                 rc = -ENOMEM;
633                 goto out;
634         }
635         old_fs = get_fs();
636         set_fs(get_ds());
637         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
638                         "lower_dentry->d_name.name = [%s]\n",
639                         lower_dentry->d_name.name);
640         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
641                                                    (char __user *)lower_buf,
642                                                    bufsiz);
643         set_fs(old_fs);
644         if (rc >= 0) {
645                 crypt_stat = NULL;
646                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
647                                               &decoded_name);
648                 if (rc == -ENOMEM)
649                         goto out_free_lower_buf;
650                 if (rc > 0) {
651                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
652                                         "to userspace: [%*s]\n", rc,
653                                         decoded_name);
654                         if (copy_to_user(buf, decoded_name, rc))
655                                 rc = -EFAULT;
656                 }
657                 kfree(decoded_name);
658                 fsstack_copy_attr_atime(dentry->d_inode,
659                                         lower_dentry->d_inode);
660         }
661 out_free_lower_buf:
662         kfree(lower_buf);
663 out:
664         return rc;
665 }
666
667 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
668 {
669         char *buf;
670         int len = PAGE_SIZE, rc;
671         mm_segment_t old_fs;
672
673         /* Released in ecryptfs_put_link(); only release here on error */
674         buf = kmalloc(len, GFP_KERNEL);
675         if (!buf) {
676                 rc = -ENOMEM;
677                 goto out;
678         }
679         old_fs = get_fs();
680         set_fs(get_ds());
681         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
682                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
683         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
684         buf[rc] = '\0';
685         set_fs(old_fs);
686         if (rc < 0)
687                 goto out_free;
688         rc = 0;
689         nd_set_link(nd, buf);
690         goto out;
691 out_free:
692         kfree(buf);
693 out:
694         return ERR_PTR(rc);
695 }
696
697 static void
698 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
699 {
700         /* Free the char* */
701         kfree(nd_get_link(nd));
702 }
703
704 /**
705  * upper_size_to_lower_size
706  * @crypt_stat: Crypt_stat associated with file
707  * @upper_size: Size of the upper file
708  *
709  * Calculate the requried size of the lower file based on the
710  * specified size of the upper file. This calculation is based on the
711  * number of headers in the underlying file and the extent size.
712  *
713  * Returns Calculated size of the lower file.
714  */
715 static loff_t
716 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
717                          loff_t upper_size)
718 {
719         loff_t lower_size;
720
721         lower_size = ( crypt_stat->header_extent_size
722                        * crypt_stat->num_header_extents_at_front );
723         if (upper_size != 0) {
724                 loff_t num_extents;
725
726                 num_extents = upper_size >> crypt_stat->extent_shift;
727                 if (upper_size & ~crypt_stat->extent_mask)
728                         num_extents++;
729                 lower_size += (num_extents * crypt_stat->extent_size);
730         }
731         return lower_size;
732 }
733
734 /**
735  * ecryptfs_truncate
736  * @dentry: The ecryptfs layer dentry
737  * @new_length: The length to expand the file to
738  *
739  * Function to handle truncations modifying the size of the file. Note
740  * that the file sizes are interpolated. When expanding, we are simply
741  * writing strings of 0's out. When truncating, we need to modify the
742  * underlying file size according to the page index interpolations.
743  *
744  * Returns zero on success; non-zero otherwise
745  */
746 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
747 {
748         int rc = 0;
749         struct inode *inode = dentry->d_inode;
750         struct dentry *lower_dentry;
751         struct vfsmount *lower_mnt;
752         struct file fake_ecryptfs_file, *lower_file = NULL;
753         struct ecryptfs_crypt_stat *crypt_stat;
754         loff_t i_size = i_size_read(inode);
755         loff_t lower_size_before_truncate;
756         loff_t lower_size_after_truncate;
757
758         if (unlikely((new_length == i_size)))
759                 goto out;
760         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
761         /* Set up a fake ecryptfs file, this is used to interface with
762          * the file in the underlying filesystem so that the
763          * truncation has an effect there as well. */
764         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
765         fake_ecryptfs_file.f_path.dentry = dentry;
766         /* Released at out_free: label */
767         ecryptfs_set_file_private(&fake_ecryptfs_file,
768                                   kmem_cache_alloc(ecryptfs_file_info_cache,
769                                                    GFP_KERNEL));
770         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
771                 rc = -ENOMEM;
772                 goto out;
773         }
774         lower_dentry = ecryptfs_dentry_to_lower(dentry);
775         /* This dget & mntget is released through fput at out_fput: */
776         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
777         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
778                                            O_RDWR))) {
779                 ecryptfs_printk(KERN_ERR,
780                                 "Error opening dentry; rc = [%i]\n", rc);
781                 goto out_free;
782         }
783         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
784         /* Switch on growing or shrinking file */
785         if (new_length > i_size) {
786                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
787                 if (rc) {
788                         ecryptfs_printk(KERN_ERR,
789                                         "Problem with fill_zeros\n");
790                         goto out_fput;
791                 }
792                 i_size_write(inode, new_length);
793                 rc = ecryptfs_write_inode_size_to_metadata(
794                         lower_file, lower_dentry->d_inode, inode, dentry,
795                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
796                 if (rc) {
797                         printk(KERN_ERR "Problem with "
798                                "ecryptfs_write_inode_size_to_metadata; "
799                                "rc = [%d]\n", rc);
800                         goto out_fput;
801                 }
802         } else { /* new_length < i_size_read(inode) */
803                 pgoff_t index = 0;
804                 int end_pos_in_page = -1;
805
806                 if (new_length != 0) {
807                         index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
808                         end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
809                 }
810                 if (end_pos_in_page != (PAGE_CACHE_SIZE - 1)) {
811                         if ((rc = ecryptfs_write_zeros(&fake_ecryptfs_file,
812                                                        index,
813                                                        (end_pos_in_page + 1),
814                                                        ((PAGE_CACHE_SIZE - 1)
815                                                         - end_pos_in_page)))) {
816                                 printk(KERN_ERR "Error attempting to zero out "
817                                        "the remainder of the end page on "
818                                        "reducing truncate; rc = [%d]\n", rc);
819                                 goto out_fput;
820                         }
821                 }
822                 vmtruncate(inode, new_length);
823                 rc = ecryptfs_write_inode_size_to_metadata(
824                         lower_file, lower_dentry->d_inode, inode, dentry,
825                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
826                 if (rc) {
827                         printk(KERN_ERR "Problem with "
828                                "ecryptfs_write_inode_size_to_metadata; "
829                                "rc = [%d]\n", rc);
830                         goto out_fput;
831                 }
832                 /* We are reducing the size of the ecryptfs file, and need to
833                  * know if we need to reduce the size of the lower file. */
834                 lower_size_before_truncate =
835                     upper_size_to_lower_size(crypt_stat, i_size);
836                 lower_size_after_truncate =
837                     upper_size_to_lower_size(crypt_stat, new_length);
838                 if (lower_size_after_truncate < lower_size_before_truncate)
839                         vmtruncate(lower_dentry->d_inode,
840                                    lower_size_after_truncate);
841         }
842         /* Update the access times */
843         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
844                 = CURRENT_TIME;
845         mark_inode_dirty_sync(inode);
846 out_fput:
847         if ((rc = ecryptfs_close_lower_file(lower_file)))
848                 printk(KERN_ERR "Error closing lower_file\n");
849 out_free:
850         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
851                 kmem_cache_free(ecryptfs_file_info_cache,
852                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
853 out:
854         return rc;
855 }
856
857 static int
858 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
859 {
860         int rc;
861
862         if (nd) {
863                 struct vfsmount *vfsmnt_save = nd->mnt;
864                 struct dentry *dentry_save = nd->dentry;
865
866                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
867                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
868                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
869                 nd->mnt = vfsmnt_save;
870                 nd->dentry = dentry_save;
871         } else
872                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
873         return rc;
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 vfsmount *lower_mnt;
909                 struct file *lower_file = NULL;
910                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
911                 int lower_flags;
912
913                 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
914                 lower_flags = O_RDONLY;
915                 if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
916                                                    lower_mnt, lower_flags))) {
917                         printk(KERN_ERR
918                                "Error opening lower file; rc = [%d]\n", rc);
919                         mutex_unlock(&crypt_stat->cs_mutex);
920                         goto out;
921                 }
922                 mount_crypt_stat = &ecryptfs_superblock_to_private(
923                         dentry->d_sb)->mount_crypt_stat;
924                 if ((rc = ecryptfs_read_metadata(dentry, lower_file))) {
925                         if (!(mount_crypt_stat->flags
926                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
927                                 rc = -EIO;
928                                 printk(KERN_WARNING "Attempt to read file that "
929                                        "is not in a valid eCryptfs format, "
930                                        "and plaintext passthrough mode is not "
931                                        "enabled; returning -EIO\n");
932
933                                 mutex_unlock(&crypt_stat->cs_mutex);
934                                 fput(lower_file);
935                                 goto out;
936                         }
937                         rc = 0;
938                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
939                         mutex_unlock(&crypt_stat->cs_mutex);
940                         fput(lower_file);
941                         goto out;
942                 }
943                 fput(lower_file);
944         }
945         mutex_unlock(&crypt_stat->cs_mutex);
946         if (ia->ia_valid & ATTR_SIZE) {
947                 ecryptfs_printk(KERN_DEBUG,
948                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
949                                 ia->ia_valid, ATTR_SIZE);
950                 rc = ecryptfs_truncate(dentry, ia->ia_size);
951                 /* ecryptfs_truncate handles resizing of the lower file */
952                 ia->ia_valid &= ~ATTR_SIZE;
953                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
954                                 ia->ia_valid);
955                 if (rc < 0)
956                         goto out;
957         }
958         rc = notify_change(lower_dentry, ia);
959 out:
960         fsstack_copy_attr_all(inode, lower_inode, NULL);
961         return rc;
962 }
963
964 int
965 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
966                   size_t size, int flags)
967 {
968         int rc = 0;
969         struct dentry *lower_dentry;
970
971         lower_dentry = ecryptfs_dentry_to_lower(dentry);
972         if (!lower_dentry->d_inode->i_op->setxattr) {
973                 rc = -ENOSYS;
974                 goto out;
975         }
976         mutex_lock(&lower_dentry->d_inode->i_mutex);
977         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
978                                                    size, flags);
979         mutex_unlock(&lower_dentry->d_inode->i_mutex);
980 out:
981         return rc;
982 }
983
984 ssize_t
985 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
986                   size_t size)
987 {
988         int rc = 0;
989         struct dentry *lower_dentry;
990
991         lower_dentry = ecryptfs_dentry_to_lower(dentry);
992         if (!lower_dentry->d_inode->i_op->getxattr) {
993                 rc = -ENOSYS;
994                 goto out;
995         }
996         mutex_lock(&lower_dentry->d_inode->i_mutex);
997         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
998                                                    size);
999         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1000 out:
1001         return rc;
1002 }
1003
1004 static ssize_t
1005 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1006 {
1007         int rc = 0;
1008         struct dentry *lower_dentry;
1009
1010         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1011         if (!lower_dentry->d_inode->i_op->listxattr) {
1012                 rc = -ENOSYS;
1013                 goto out;
1014         }
1015         mutex_lock(&lower_dentry->d_inode->i_mutex);
1016         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1017         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1018 out:
1019         return rc;
1020 }
1021
1022 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1023 {
1024         int rc = 0;
1025         struct dentry *lower_dentry;
1026
1027         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1028         if (!lower_dentry->d_inode->i_op->removexattr) {
1029                 rc = -ENOSYS;
1030                 goto out;
1031         }
1032         mutex_lock(&lower_dentry->d_inode->i_mutex);
1033         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1034         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1035 out:
1036         return rc;
1037 }
1038
1039 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1040 {
1041         if ((ecryptfs_inode_to_lower(inode)
1042              == (struct inode *)candidate_lower_inode))
1043                 return 1;
1044         else
1045                 return 0;
1046 }
1047
1048 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1049 {
1050         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1051         return 0;
1052 }
1053
1054 const struct inode_operations ecryptfs_symlink_iops = {
1055         .readlink = ecryptfs_readlink,
1056         .follow_link = ecryptfs_follow_link,
1057         .put_link = ecryptfs_put_link,
1058         .permission = ecryptfs_permission,
1059         .setattr = ecryptfs_setattr,
1060         .setxattr = ecryptfs_setxattr,
1061         .getxattr = ecryptfs_getxattr,
1062         .listxattr = ecryptfs_listxattr,
1063         .removexattr = ecryptfs_removexattr
1064 };
1065
1066 const struct inode_operations ecryptfs_dir_iops = {
1067         .create = ecryptfs_create,
1068         .lookup = ecryptfs_lookup,
1069         .link = ecryptfs_link,
1070         .unlink = ecryptfs_unlink,
1071         .symlink = ecryptfs_symlink,
1072         .mkdir = ecryptfs_mkdir,
1073         .rmdir = ecryptfs_rmdir,
1074         .mknod = ecryptfs_mknod,
1075         .rename = ecryptfs_rename,
1076         .permission = ecryptfs_permission,
1077         .setattr = ecryptfs_setattr,
1078         .setxattr = ecryptfs_setxattr,
1079         .getxattr = ecryptfs_getxattr,
1080         .listxattr = ecryptfs_listxattr,
1081         .removexattr = ecryptfs_removexattr
1082 };
1083
1084 const struct inode_operations ecryptfs_main_iops = {
1085         .permission = ecryptfs_permission,
1086         .setattr = ecryptfs_setattr,
1087         .setxattr = ecryptfs_setxattr,
1088         .getxattr = ecryptfs_getxattr,
1089         .listxattr = ecryptfs_listxattr,
1090         .removexattr = ecryptfs_removexattr
1091 };