Merge branch 'upstream-jeff' of git://git.kernel.org/pub/scm/linux/kernel/git/romieu...
[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 (rc) {
123                 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
124                 struct ecryptfs_inode_info *inode_info =
125                         ecryptfs_inode_to_private(ecryptfs_inode);
126
127                 printk(KERN_WARNING "%s: Error creating underlying file; "
128                        "rc = [%d]; checking for existing\n", __FUNCTION__, rc);
129                 if (inode_info) {
130                         mutex_lock(&inode_info->lower_file_mutex);
131                         if (!inode_info->lower_file) {
132                                 mutex_unlock(&inode_info->lower_file_mutex);
133                                 printk(KERN_ERR "%s: Failure to set underlying "
134                                        "file; rc = [%d]\n", __FUNCTION__, rc);
135                                 goto out_lock;
136                         }
137                         mutex_unlock(&inode_info->lower_file_mutex);
138                 }
139         }
140         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
141                                 directory_inode->i_sb, 0);
142         if (rc) {
143                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
144                 goto out_lock;
145         }
146         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
147         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
148 out_lock:
149         unlock_dir(lower_dir_dentry);
150 out:
151         return rc;
152 }
153
154 /**
155  * grow_file
156  * @ecryptfs_dentry: the eCryptfs dentry
157  *
158  * This is the code which will grow the file to its correct size.
159  */
160 static int grow_file(struct dentry *ecryptfs_dentry)
161 {
162         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
163         struct file fake_file;
164         struct ecryptfs_file_info tmp_file_info;
165         char zero_virt[] = { 0x00 };
166         int rc = 0;
167
168         memset(&fake_file, 0, sizeof(fake_file));
169         fake_file.f_path.dentry = ecryptfs_dentry;
170         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
171         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
172         ecryptfs_set_file_lower(
173                 &fake_file,
174                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
175         rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
176         i_size_write(ecryptfs_inode, 0);
177         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
178         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
179                 ECRYPTFS_NEW_FILE;
180         return rc;
181 }
182
183 /**
184  * ecryptfs_initialize_file
185  *
186  * Cause the file to be changed from a basic empty file to an ecryptfs
187  * file with a header and first data page.
188  *
189  * Returns zero on success
190  */
191 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
192 {
193         struct ecryptfs_crypt_stat *crypt_stat =
194                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
195         int rc = 0;
196
197         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
198                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
199                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
200                 goto out;
201         }
202         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
203         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
204         rc = ecryptfs_new_file_context(ecryptfs_dentry);
205         if (rc) {
206                 ecryptfs_printk(KERN_ERR, "Error creating new file "
207                                 "context; rc = [%d]\n", rc);
208                 goto out;
209         }
210         rc = ecryptfs_write_metadata(ecryptfs_dentry);
211         if (rc) {
212                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
213                 goto out;
214         }
215         rc = grow_file(ecryptfs_dentry);
216         if (rc)
217                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
218 out:
219         return rc;
220 }
221
222 /**
223  * ecryptfs_create
224  * @dir: The inode of the directory in which to create the file.
225  * @dentry: The eCryptfs dentry
226  * @mode: The mode of the new file.
227  * @nd: nameidata
228  *
229  * Creates a new file.
230  *
231  * Returns zero on success; non-zero on error condition
232  */
233 static int
234 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
235                 int mode, struct nameidata *nd)
236 {
237         int rc;
238
239         /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
240          * the crypt_stat->lower_file (persistent file) */
241         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
242         if (unlikely(rc)) {
243                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
244                                 "lower filesystem\n");
245                 goto out;
246         }
247         /* At this point, a file exists on "disk"; we need to make sure
248          * that this on disk file is prepared to be an ecryptfs file */
249         rc = ecryptfs_initialize_file(ecryptfs_dentry);
250 out:
251         return rc;
252 }
253
254 /**
255  * ecryptfs_lookup
256  * @dir: inode
257  * @dentry: The dentry
258  * @nd: nameidata, may be NULL
259  *
260  * Find a file on disk. If the file does not exist, then we'll add it to the
261  * dentry cache and continue on to read it from the disk.
262  */
263 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
264                                       struct nameidata *nd)
265 {
266         int rc = 0;
267         struct dentry *lower_dir_dentry;
268         struct dentry *lower_dentry;
269         struct vfsmount *lower_mnt;
270         char *encoded_name;
271         int encoded_namelen;
272         struct ecryptfs_crypt_stat *crypt_stat = NULL;
273         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
274         char *page_virt = NULL;
275         struct inode *lower_inode;
276         u64 file_size;
277
278         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
279         dentry->d_op = &ecryptfs_dops;
280         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
281             || (dentry->d_name.len == 2
282                 && !strcmp(dentry->d_name.name, ".."))) {
283                 d_drop(dentry);
284                 goto out;
285         }
286         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
287                                                    dentry->d_name.name,
288                                                    dentry->d_name.len,
289                                                    &encoded_name);
290         if (encoded_namelen < 0) {
291                 rc = encoded_namelen;
292                 d_drop(dentry);
293                 goto out;
294         }
295         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
296                         "= [%d]\n", encoded_name, encoded_namelen);
297         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
298                                       encoded_namelen - 1);
299         kfree(encoded_name);
300         if (IS_ERR(lower_dentry)) {
301                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
302                 rc = PTR_ERR(lower_dentry);
303                 d_drop(dentry);
304                 goto out;
305         }
306         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
307         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
308                 "d_name.name = [%s]\n", lower_dentry,
309                 lower_dentry->d_name.name);
310         lower_inode = lower_dentry->d_inode;
311         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
312         BUG_ON(!atomic_read(&lower_dentry->d_count));
313         ecryptfs_set_dentry_private(dentry,
314                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
315                                                      GFP_KERNEL));
316         if (!ecryptfs_dentry_to_private(dentry)) {
317                 rc = -ENOMEM;
318                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
319                                 "to allocate ecryptfs_dentry_info struct\n");
320                 goto out_dput;
321         }
322         ecryptfs_set_dentry_lower(dentry, lower_dentry);
323         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
324         if (!lower_dentry->d_inode) {
325                 /* We want to add because we couldn't find in lower */
326                 d_add(dentry, NULL);
327                 goto out;
328         }
329         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
330         if (rc) {
331                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
332                 goto out_dput;
333         }
334         if (S_ISDIR(lower_inode->i_mode)) {
335                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
336                 goto out;
337         }
338         if (S_ISLNK(lower_inode->i_mode)) {
339                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
340                 goto out;
341         }
342         if (special_file(lower_inode->i_mode)) {
343                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
344                 goto out;
345         }
346         if (!nd) {
347                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
348                                 "as we *think* we are about to unlink\n");
349                 goto out;
350         }
351         /* Released in this function */
352         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
353                                       GFP_USER);
354         if (!page_virt) {
355                 rc = -ENOMEM;
356                 ecryptfs_printk(KERN_ERR,
357                                 "Cannot ecryptfs_kmalloc a page\n");
358                 goto out_dput;
359         }
360         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
361         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
362                 ecryptfs_set_default_sizes(crypt_stat);
363         rc = ecryptfs_read_and_validate_header_region(page_virt,
364                                                       dentry->d_inode);
365         if (rc) {
366                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
367                 if (rc) {
368                         printk(KERN_DEBUG "Valid metadata not found in header "
369                                "region or xattr region; treating file as "
370                                "unencrypted\n");
371                         rc = 0;
372                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
373                         goto out;
374                 }
375                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
376         }
377         mount_crypt_stat = &ecryptfs_superblock_to_private(
378                 dentry->d_sb)->mount_crypt_stat;
379         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
380                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
381                         file_size = ((crypt_stat->extent_size
382                                       * crypt_stat->num_header_extents_at_front)
383                                      + i_size_read(lower_dentry->d_inode));
384                 else
385                         file_size = i_size_read(lower_dentry->d_inode);
386         } else {
387                 memcpy(&file_size, page_virt, sizeof(file_size));
388                 file_size = be64_to_cpu(file_size);
389         }
390         i_size_write(dentry->d_inode, (loff_t)file_size);
391         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
392         goto out;
393
394 out_dput:
395         dput(lower_dentry);
396         d_drop(dentry);
397 out:
398         return ERR_PTR(rc);
399 }
400
401 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
402                          struct dentry *new_dentry)
403 {
404         struct dentry *lower_old_dentry;
405         struct dentry *lower_new_dentry;
406         struct dentry *lower_dir_dentry;
407         u64 file_size_save;
408         int rc;
409
410         file_size_save = i_size_read(old_dentry->d_inode);
411         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
412         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
413         dget(lower_old_dentry);
414         dget(lower_new_dentry);
415         lower_dir_dentry = lock_parent(lower_new_dentry);
416         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
417                       lower_new_dentry);
418         if (rc || !lower_new_dentry->d_inode)
419                 goto out_lock;
420         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
421         if (rc)
422                 goto out_lock;
423         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
424         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
425         old_dentry->d_inode->i_nlink =
426                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
427         i_size_write(new_dentry->d_inode, file_size_save);
428 out_lock:
429         unlock_dir(lower_dir_dentry);
430         dput(lower_new_dentry);
431         dput(lower_old_dentry);
432         d_drop(lower_old_dentry);
433         d_drop(new_dentry);
434         d_drop(old_dentry);
435         return rc;
436 }
437
438 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
439 {
440         int rc = 0;
441         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
442         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
443
444         lock_parent(lower_dentry);
445         rc = vfs_unlink(lower_dir_inode, lower_dentry);
446         if (rc) {
447                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
448                 goto out_unlock;
449         }
450         fsstack_copy_attr_times(dir, lower_dir_inode);
451         dentry->d_inode->i_nlink =
452                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
453         dentry->d_inode->i_ctime = dir->i_ctime;
454 out_unlock:
455         unlock_parent(lower_dentry);
456         return rc;
457 }
458
459 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
460                             const char *symname)
461 {
462         int rc;
463         struct dentry *lower_dentry;
464         struct dentry *lower_dir_dentry;
465         umode_t mode;
466         char *encoded_symname;
467         int encoded_symlen;
468         struct ecryptfs_crypt_stat *crypt_stat = NULL;
469
470         lower_dentry = ecryptfs_dentry_to_lower(dentry);
471         dget(lower_dentry);
472         lower_dir_dentry = lock_parent(lower_dentry);
473         mode = S_IALLUGO;
474         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
475                                                   strlen(symname),
476                                                   &encoded_symname);
477         if (encoded_symlen < 0) {
478                 rc = encoded_symlen;
479                 goto out_lock;
480         }
481         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
482                          encoded_symname, mode);
483         kfree(encoded_symname);
484         if (rc || !lower_dentry->d_inode)
485                 goto out_lock;
486         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
487         if (rc)
488                 goto out_lock;
489         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
490         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
491 out_lock:
492         unlock_dir(lower_dir_dentry);
493         dput(lower_dentry);
494         if (!dentry->d_inode)
495                 d_drop(dentry);
496         return rc;
497 }
498
499 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
500 {
501         int rc;
502         struct dentry *lower_dentry;
503         struct dentry *lower_dir_dentry;
504
505         lower_dentry = ecryptfs_dentry_to_lower(dentry);
506         lower_dir_dentry = lock_parent(lower_dentry);
507         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
508         if (rc || !lower_dentry->d_inode)
509                 goto out;
510         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
511         if (rc)
512                 goto out;
513         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
514         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
515         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
516 out:
517         unlock_dir(lower_dir_dentry);
518         if (!dentry->d_inode)
519                 d_drop(dentry);
520         return rc;
521 }
522
523 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
524 {
525         struct dentry *lower_dentry;
526         struct dentry *lower_dir_dentry;
527         int rc;
528
529         lower_dentry = ecryptfs_dentry_to_lower(dentry);
530         dget(dentry);
531         lower_dir_dentry = lock_parent(lower_dentry);
532         dget(lower_dentry);
533         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
534         dput(lower_dentry);
535         if (!rc)
536                 d_delete(lower_dentry);
537         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
538         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
539         unlock_dir(lower_dir_dentry);
540         if (!rc)
541                 d_drop(dentry);
542         dput(dentry);
543         return rc;
544 }
545
546 static int
547 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
548 {
549         int rc;
550         struct dentry *lower_dentry;
551         struct dentry *lower_dir_dentry;
552
553         lower_dentry = ecryptfs_dentry_to_lower(dentry);
554         lower_dir_dentry = lock_parent(lower_dentry);
555         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
556         if (rc || !lower_dentry->d_inode)
557                 goto out;
558         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
559         if (rc)
560                 goto out;
561         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
562         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
563 out:
564         unlock_dir(lower_dir_dentry);
565         if (!dentry->d_inode)
566                 d_drop(dentry);
567         return rc;
568 }
569
570 static int
571 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
572                 struct inode *new_dir, struct dentry *new_dentry)
573 {
574         int rc;
575         struct dentry *lower_old_dentry;
576         struct dentry *lower_new_dentry;
577         struct dentry *lower_old_dir_dentry;
578         struct dentry *lower_new_dir_dentry;
579
580         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
581         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
582         dget(lower_old_dentry);
583         dget(lower_new_dentry);
584         lower_old_dir_dentry = dget_parent(lower_old_dentry);
585         lower_new_dir_dentry = dget_parent(lower_new_dentry);
586         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
587         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
588                         lower_new_dir_dentry->d_inode, lower_new_dentry);
589         if (rc)
590                 goto out_lock;
591         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
592         if (new_dir != old_dir)
593                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
594 out_lock:
595         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
596         dput(lower_new_dentry->d_parent);
597         dput(lower_old_dentry->d_parent);
598         dput(lower_new_dentry);
599         dput(lower_old_dentry);
600         return rc;
601 }
602
603 static int
604 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
605 {
606         int rc;
607         struct dentry *lower_dentry;
608         char *decoded_name;
609         char *lower_buf;
610         mm_segment_t old_fs;
611         struct ecryptfs_crypt_stat *crypt_stat;
612
613         lower_dentry = ecryptfs_dentry_to_lower(dentry);
614         if (!lower_dentry->d_inode->i_op ||
615             !lower_dentry->d_inode->i_op->readlink) {
616                 rc = -EINVAL;
617                 goto out;
618         }
619         /* Released in this function */
620         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
621         if (lower_buf == NULL) {
622                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
623                 rc = -ENOMEM;
624                 goto out;
625         }
626         old_fs = get_fs();
627         set_fs(get_ds());
628         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
629                         "lower_dentry->d_name.name = [%s]\n",
630                         lower_dentry->d_name.name);
631         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
632                                                    (char __user *)lower_buf,
633                                                    bufsiz);
634         set_fs(old_fs);
635         if (rc >= 0) {
636                 crypt_stat = NULL;
637                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
638                                               &decoded_name);
639                 if (rc == -ENOMEM)
640                         goto out_free_lower_buf;
641                 if (rc > 0) {
642                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
643                                         "to userspace: [%*s]\n", rc,
644                                         decoded_name);
645                         if (copy_to_user(buf, decoded_name, rc))
646                                 rc = -EFAULT;
647                 }
648                 kfree(decoded_name);
649                 fsstack_copy_attr_atime(dentry->d_inode,
650                                         lower_dentry->d_inode);
651         }
652 out_free_lower_buf:
653         kfree(lower_buf);
654 out:
655         return rc;
656 }
657
658 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
659 {
660         char *buf;
661         int len = PAGE_SIZE, rc;
662         mm_segment_t old_fs;
663
664         /* Released in ecryptfs_put_link(); only release here on error */
665         buf = kmalloc(len, GFP_KERNEL);
666         if (!buf) {
667                 rc = -ENOMEM;
668                 goto out;
669         }
670         old_fs = get_fs();
671         set_fs(get_ds());
672         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
673                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
674         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
675         buf[rc] = '\0';
676         set_fs(old_fs);
677         if (rc < 0)
678                 goto out_free;
679         rc = 0;
680         nd_set_link(nd, buf);
681         goto out;
682 out_free:
683         kfree(buf);
684 out:
685         return ERR_PTR(rc);
686 }
687
688 static void
689 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
690 {
691         /* Free the char* */
692         kfree(nd_get_link(nd));
693 }
694
695 /**
696  * upper_size_to_lower_size
697  * @crypt_stat: Crypt_stat associated with file
698  * @upper_size: Size of the upper file
699  *
700  * Calculate the requried size of the lower file based on the
701  * specified size of the upper file. This calculation is based on the
702  * number of headers in the underlying file and the extent size.
703  *
704  * Returns Calculated size of the lower file.
705  */
706 static loff_t
707 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
708                          loff_t upper_size)
709 {
710         loff_t lower_size;
711
712         lower_size = (crypt_stat->extent_size
713                       * crypt_stat->num_header_extents_at_front);
714         if (upper_size != 0) {
715                 loff_t num_extents;
716
717                 num_extents = upper_size >> crypt_stat->extent_shift;
718                 if (upper_size & ~crypt_stat->extent_mask)
719                         num_extents++;
720                 lower_size += (num_extents * crypt_stat->extent_size);
721         }
722         return lower_size;
723 }
724
725 /**
726  * ecryptfs_truncate
727  * @dentry: The ecryptfs layer dentry
728  * @new_length: The length to expand the file to
729  *
730  * Function to handle truncations modifying the size of the file. Note
731  * that the file sizes are interpolated. When expanding, we are simply
732  * writing strings of 0's out. When truncating, we need to modify the
733  * underlying file size according to the page index interpolations.
734  *
735  * Returns zero on success; non-zero otherwise
736  */
737 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
738 {
739         int rc = 0;
740         struct inode *inode = dentry->d_inode;
741         struct dentry *lower_dentry;
742         struct file fake_ecryptfs_file;
743         struct ecryptfs_crypt_stat *crypt_stat;
744         loff_t i_size = i_size_read(inode);
745         loff_t lower_size_before_truncate;
746         loff_t lower_size_after_truncate;
747
748         if (unlikely((new_length == i_size)))
749                 goto out;
750         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
751         /* Set up a fake ecryptfs file, this is used to interface with
752          * the file in the underlying filesystem so that the
753          * truncation has an effect there as well. */
754         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
755         fake_ecryptfs_file.f_path.dentry = dentry;
756         /* Released at out_free: label */
757         ecryptfs_set_file_private(&fake_ecryptfs_file,
758                                   kmem_cache_alloc(ecryptfs_file_info_cache,
759                                                    GFP_KERNEL));
760         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
761                 rc = -ENOMEM;
762                 goto out;
763         }
764         lower_dentry = ecryptfs_dentry_to_lower(dentry);
765         ecryptfs_set_file_lower(
766                 &fake_ecryptfs_file,
767                 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
768         /* Switch on growing or shrinking file */
769         if (new_length > i_size) {
770                 char zero[] = { 0x00 };
771
772                 /* Write a single 0 at the last position of the file;
773                  * this triggers code that will fill in 0's throughout
774                  * the intermediate portion of the previous end of the
775                  * file and the new and of the file */
776                 rc = ecryptfs_write(&fake_ecryptfs_file, zero,
777                                     (new_length - 1), 1);
778         } else { /* new_length < i_size_read(inode) */
779                 /* We're chopping off all the pages down do the page
780                  * in which new_length is located. Fill in the end of
781                  * that page from (new_length & ~PAGE_CACHE_MASK) to
782                  * PAGE_CACHE_SIZE with zeros. */
783                 size_t num_zeros = (PAGE_CACHE_SIZE
784                                     - (new_length & ~PAGE_CACHE_MASK));
785
786                 if (num_zeros) {
787                         char *zeros_virt;
788
789                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
790                         if (!zeros_virt) {
791                                 rc = -ENOMEM;
792                                 goto out_free;
793                         }
794                         rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
795                                             new_length, num_zeros);
796                         kfree(zeros_virt);
797                         if (rc) {
798                                 printk(KERN_ERR "Error attempting to zero out "
799                                        "the remainder of the end page on "
800                                        "reducing truncate; rc = [%d]\n", rc);
801                                 goto out_free;
802                         }
803                 }
804                 vmtruncate(inode, new_length);
805                 rc = ecryptfs_write_inode_size_to_metadata(inode);
806                 if (rc) {
807                         printk(KERN_ERR "Problem with "
808                                "ecryptfs_write_inode_size_to_metadata; "
809                                "rc = [%d]\n", rc);
810                         goto out_free;
811                 }
812                 /* We are reducing the size of the ecryptfs file, and need to
813                  * know if we need to reduce the size of the lower file. */
814                 lower_size_before_truncate =
815                     upper_size_to_lower_size(crypt_stat, i_size);
816                 lower_size_after_truncate =
817                     upper_size_to_lower_size(crypt_stat, new_length);
818                 if (lower_size_after_truncate < lower_size_before_truncate)
819                         vmtruncate(lower_dentry->d_inode,
820                                    lower_size_after_truncate);
821         }
822 out_free:
823         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
824                 kmem_cache_free(ecryptfs_file_info_cache,
825                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
826 out:
827         return rc;
828 }
829
830 static int
831 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
832 {
833         int rc;
834
835         if (nd) {
836                 struct vfsmount *vfsmnt_save = nd->mnt;
837                 struct dentry *dentry_save = nd->dentry;
838
839                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
840                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
841                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
842                 nd->mnt = vfsmnt_save;
843                 nd->dentry = dentry_save;
844         } else
845                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
846         return rc;
847 }
848
849 /**
850  * ecryptfs_setattr
851  * @dentry: dentry handle to the inode to modify
852  * @ia: Structure with flags of what to change and values
853  *
854  * Updates the metadata of an inode. If the update is to the size
855  * i.e. truncation, then ecryptfs_truncate will handle the size modification
856  * of both the ecryptfs inode and the lower inode.
857  *
858  * All other metadata changes will be passed right to the lower filesystem,
859  * and we will just update our inode to look like the lower.
860  */
861 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
862 {
863         int rc = 0;
864         struct dentry *lower_dentry;
865         struct inode *inode;
866         struct inode *lower_inode;
867         struct ecryptfs_crypt_stat *crypt_stat;
868
869         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
870         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
871                 ecryptfs_init_crypt_stat(crypt_stat);
872         inode = dentry->d_inode;
873         lower_inode = ecryptfs_inode_to_lower(inode);
874         lower_dentry = ecryptfs_dentry_to_lower(dentry);
875         mutex_lock(&crypt_stat->cs_mutex);
876         if (S_ISDIR(dentry->d_inode->i_mode))
877                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
878         else if (S_ISREG(dentry->d_inode->i_mode)
879                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
880                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
881                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
882
883                 mount_crypt_stat = &ecryptfs_superblock_to_private(
884                         dentry->d_sb)->mount_crypt_stat;
885                 rc = ecryptfs_read_metadata(dentry);
886                 if (rc) {
887                         if (!(mount_crypt_stat->flags
888                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
889                                 rc = -EIO;
890                                 printk(KERN_WARNING "Attempt to read file that "
891                                        "is not in a valid eCryptfs format, "
892                                        "and plaintext passthrough mode is not "
893                                        "enabled; returning -EIO\n");
894
895                                 mutex_unlock(&crypt_stat->cs_mutex);
896                                 goto out;
897                         }
898                         rc = 0;
899                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
900                         mutex_unlock(&crypt_stat->cs_mutex);
901                         goto out;
902                 }
903         }
904         mutex_unlock(&crypt_stat->cs_mutex);
905         if (ia->ia_valid & ATTR_SIZE) {
906                 ecryptfs_printk(KERN_DEBUG,
907                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
908                                 ia->ia_valid, ATTR_SIZE);
909                 rc = ecryptfs_truncate(dentry, ia->ia_size);
910                 /* ecryptfs_truncate handles resizing of the lower file */
911                 ia->ia_valid &= ~ATTR_SIZE;
912                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
913                                 ia->ia_valid);
914                 if (rc < 0)
915                         goto out;
916         }
917
918         /*
919          * mode change is for clearing setuid/setgid bits. Allow lower fs
920          * to interpret this in its own way.
921          */
922         if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
923                 ia->ia_valid &= ~ATTR_MODE;
924
925         rc = notify_change(lower_dentry, ia);
926 out:
927         fsstack_copy_attr_all(inode, lower_inode, NULL);
928         return rc;
929 }
930
931 int
932 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
933                   size_t size, int flags)
934 {
935         int rc = 0;
936         struct dentry *lower_dentry;
937
938         lower_dentry = ecryptfs_dentry_to_lower(dentry);
939         if (!lower_dentry->d_inode->i_op->setxattr) {
940                 rc = -ENOSYS;
941                 goto out;
942         }
943         mutex_lock(&lower_dentry->d_inode->i_mutex);
944         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
945                                                    size, flags);
946         mutex_unlock(&lower_dentry->d_inode->i_mutex);
947 out:
948         return rc;
949 }
950
951 ssize_t
952 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
953                         void *value, size_t size)
954 {
955         int rc = 0;
956
957         if (!lower_dentry->d_inode->i_op->getxattr) {
958                 rc = -ENOSYS;
959                 goto out;
960         }
961         mutex_lock(&lower_dentry->d_inode->i_mutex);
962         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
963                                                    size);
964         mutex_unlock(&lower_dentry->d_inode->i_mutex);
965 out:
966         return rc;
967 }
968
969 ssize_t
970 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
971                   size_t size)
972 {
973         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
974                                        value, size);
975 }
976
977 static ssize_t
978 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
979 {
980         int rc = 0;
981         struct dentry *lower_dentry;
982
983         lower_dentry = ecryptfs_dentry_to_lower(dentry);
984         if (!lower_dentry->d_inode->i_op->listxattr) {
985                 rc = -ENOSYS;
986                 goto out;
987         }
988         mutex_lock(&lower_dentry->d_inode->i_mutex);
989         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
990         mutex_unlock(&lower_dentry->d_inode->i_mutex);
991 out:
992         return rc;
993 }
994
995 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
996 {
997         int rc = 0;
998         struct dentry *lower_dentry;
999
1000         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1001         if (!lower_dentry->d_inode->i_op->removexattr) {
1002                 rc = -ENOSYS;
1003                 goto out;
1004         }
1005         mutex_lock(&lower_dentry->d_inode->i_mutex);
1006         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1007         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1008 out:
1009         return rc;
1010 }
1011
1012 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1013 {
1014         if ((ecryptfs_inode_to_lower(inode)
1015              == (struct inode *)candidate_lower_inode))
1016                 return 1;
1017         else
1018                 return 0;
1019 }
1020
1021 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1022 {
1023         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1024         return 0;
1025 }
1026
1027 const struct inode_operations ecryptfs_symlink_iops = {
1028         .readlink = ecryptfs_readlink,
1029         .follow_link = ecryptfs_follow_link,
1030         .put_link = ecryptfs_put_link,
1031         .permission = ecryptfs_permission,
1032         .setattr = ecryptfs_setattr,
1033         .setxattr = ecryptfs_setxattr,
1034         .getxattr = ecryptfs_getxattr,
1035         .listxattr = ecryptfs_listxattr,
1036         .removexattr = ecryptfs_removexattr
1037 };
1038
1039 const struct inode_operations ecryptfs_dir_iops = {
1040         .create = ecryptfs_create,
1041         .lookup = ecryptfs_lookup,
1042         .link = ecryptfs_link,
1043         .unlink = ecryptfs_unlink,
1044         .symlink = ecryptfs_symlink,
1045         .mkdir = ecryptfs_mkdir,
1046         .rmdir = ecryptfs_rmdir,
1047         .mknod = ecryptfs_mknod,
1048         .rename = ecryptfs_rename,
1049         .permission = ecryptfs_permission,
1050         .setattr = ecryptfs_setattr,
1051         .setxattr = ecryptfs_setxattr,
1052         .getxattr = ecryptfs_getxattr,
1053         .listxattr = ecryptfs_listxattr,
1054         .removexattr = ecryptfs_removexattr
1055 };
1056
1057 const struct inode_operations ecryptfs_main_iops = {
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 };