Pull misc 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 (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->header_extent_size
396                                      + i_size_read(lower_dentry->d_inode));
397                 else
398                         file_size = i_size_read(lower_dentry->d_inode);
399         } else {
400                 memcpy(&file_size, page_virt, sizeof(file_size));
401                 file_size = be64_to_cpu(file_size);
402         }
403         i_size_write(dentry->d_inode, (loff_t)file_size);
404         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
405         goto out;
406
407 out_dput:
408         dput(lower_dentry);
409         d_drop(dentry);
410 out:
411         return ERR_PTR(rc);
412 }
413
414 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
415                          struct dentry *new_dentry)
416 {
417         struct dentry *lower_old_dentry;
418         struct dentry *lower_new_dentry;
419         struct dentry *lower_dir_dentry;
420         u64 file_size_save;
421         int rc;
422
423         file_size_save = i_size_read(old_dentry->d_inode);
424         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
425         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
426         dget(lower_old_dentry);
427         dget(lower_new_dentry);
428         lower_dir_dentry = lock_parent(lower_new_dentry);
429         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
430                       lower_new_dentry);
431         if (rc || !lower_new_dentry->d_inode)
432                 goto out_lock;
433         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
434         if (rc)
435                 goto out_lock;
436         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
437         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
438         old_dentry->d_inode->i_nlink =
439                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
440         i_size_write(new_dentry->d_inode, file_size_save);
441 out_lock:
442         unlock_dir(lower_dir_dentry);
443         dput(lower_new_dentry);
444         dput(lower_old_dentry);
445         d_drop(lower_old_dentry);
446         d_drop(new_dentry);
447         d_drop(old_dentry);
448         return rc;
449 }
450
451 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
452 {
453         int rc = 0;
454         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
455         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
456
457         lock_parent(lower_dentry);
458         rc = vfs_unlink(lower_dir_inode, lower_dentry);
459         if (rc) {
460                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
461                 goto out_unlock;
462         }
463         fsstack_copy_attr_times(dir, lower_dir_inode);
464         dentry->d_inode->i_nlink =
465                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
466         dentry->d_inode->i_ctime = dir->i_ctime;
467 out_unlock:
468         unlock_parent(lower_dentry);
469         return rc;
470 }
471
472 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
473                             const char *symname)
474 {
475         int rc;
476         struct dentry *lower_dentry;
477         struct dentry *lower_dir_dentry;
478         umode_t mode;
479         char *encoded_symname;
480         int encoded_symlen;
481         struct ecryptfs_crypt_stat *crypt_stat = NULL;
482
483         lower_dentry = ecryptfs_dentry_to_lower(dentry);
484         dget(lower_dentry);
485         lower_dir_dentry = lock_parent(lower_dentry);
486         mode = S_IALLUGO;
487         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
488                                                   strlen(symname),
489                                                   &encoded_symname);
490         if (encoded_symlen < 0) {
491                 rc = encoded_symlen;
492                 goto out_lock;
493         }
494         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
495                          encoded_symname, mode);
496         kfree(encoded_symname);
497         if (rc || !lower_dentry->d_inode)
498                 goto out_lock;
499         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
500         if (rc)
501                 goto out_lock;
502         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
503         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
504 out_lock:
505         unlock_dir(lower_dir_dentry);
506         dput(lower_dentry);
507         if (!dentry->d_inode)
508                 d_drop(dentry);
509         return rc;
510 }
511
512 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
513 {
514         int rc;
515         struct dentry *lower_dentry;
516         struct dentry *lower_dir_dentry;
517
518         lower_dentry = ecryptfs_dentry_to_lower(dentry);
519         lower_dir_dentry = lock_parent(lower_dentry);
520         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
521         if (rc || !lower_dentry->d_inode)
522                 goto out;
523         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
524         if (rc)
525                 goto out;
526         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
527         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
528         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
529 out:
530         unlock_dir(lower_dir_dentry);
531         if (!dentry->d_inode)
532                 d_drop(dentry);
533         return rc;
534 }
535
536 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
537 {
538         struct dentry *lower_dentry;
539         struct dentry *lower_dir_dentry;
540         int rc;
541
542         lower_dentry = ecryptfs_dentry_to_lower(dentry);
543         dget(dentry);
544         lower_dir_dentry = lock_parent(lower_dentry);
545         dget(lower_dentry);
546         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
547         dput(lower_dentry);
548         if (!rc)
549                 d_delete(lower_dentry);
550         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
551         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
552         unlock_dir(lower_dir_dentry);
553         if (!rc)
554                 d_drop(dentry);
555         dput(dentry);
556         return rc;
557 }
558
559 static int
560 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
561 {
562         int rc;
563         struct dentry *lower_dentry;
564         struct dentry *lower_dir_dentry;
565
566         lower_dentry = ecryptfs_dentry_to_lower(dentry);
567         lower_dir_dentry = lock_parent(lower_dentry);
568         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
569         if (rc || !lower_dentry->d_inode)
570                 goto out;
571         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
572         if (rc)
573                 goto out;
574         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
575         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
576 out:
577         unlock_dir(lower_dir_dentry);
578         if (!dentry->d_inode)
579                 d_drop(dentry);
580         return rc;
581 }
582
583 static int
584 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
585                 struct inode *new_dir, struct dentry *new_dentry)
586 {
587         int rc;
588         struct dentry *lower_old_dentry;
589         struct dentry *lower_new_dentry;
590         struct dentry *lower_old_dir_dentry;
591         struct dentry *lower_new_dir_dentry;
592
593         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
594         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
595         dget(lower_old_dentry);
596         dget(lower_new_dentry);
597         lower_old_dir_dentry = dget_parent(lower_old_dentry);
598         lower_new_dir_dentry = dget_parent(lower_new_dentry);
599         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
600         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
601                         lower_new_dir_dentry->d_inode, lower_new_dentry);
602         if (rc)
603                 goto out_lock;
604         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
605         if (new_dir != old_dir)
606                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
607 out_lock:
608         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
609         dput(lower_new_dentry->d_parent);
610         dput(lower_old_dentry->d_parent);
611         dput(lower_new_dentry);
612         dput(lower_old_dentry);
613         return rc;
614 }
615
616 static int
617 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
618 {
619         int rc;
620         struct dentry *lower_dentry;
621         char *decoded_name;
622         char *lower_buf;
623         mm_segment_t old_fs;
624         struct ecryptfs_crypt_stat *crypt_stat;
625
626         lower_dentry = ecryptfs_dentry_to_lower(dentry);
627         if (!lower_dentry->d_inode->i_op ||
628             !lower_dentry->d_inode->i_op->readlink) {
629                 rc = -EINVAL;
630                 goto out;
631         }
632         /* Released in this function */
633         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
634         if (lower_buf == NULL) {
635                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
636                 rc = -ENOMEM;
637                 goto out;
638         }
639         old_fs = get_fs();
640         set_fs(get_ds());
641         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
642                         "lower_dentry->d_name.name = [%s]\n",
643                         lower_dentry->d_name.name);
644         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
645                                                    (char __user *)lower_buf,
646                                                    bufsiz);
647         set_fs(old_fs);
648         if (rc >= 0) {
649                 crypt_stat = NULL;
650                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
651                                               &decoded_name);
652                 if (rc == -ENOMEM)
653                         goto out_free_lower_buf;
654                 if (rc > 0) {
655                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
656                                         "to userspace: [%*s]\n", rc,
657                                         decoded_name);
658                         if (copy_to_user(buf, decoded_name, rc))
659                                 rc = -EFAULT;
660                 }
661                 kfree(decoded_name);
662                 fsstack_copy_attr_atime(dentry->d_inode,
663                                         lower_dentry->d_inode);
664         }
665 out_free_lower_buf:
666         kfree(lower_buf);
667 out:
668         return rc;
669 }
670
671 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
672 {
673         char *buf;
674         int len = PAGE_SIZE, rc;
675         mm_segment_t old_fs;
676
677         /* Released in ecryptfs_put_link(); only release here on error */
678         buf = kmalloc(len, GFP_KERNEL);
679         if (!buf) {
680                 rc = -ENOMEM;
681                 goto out;
682         }
683         old_fs = get_fs();
684         set_fs(get_ds());
685         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
686                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
687         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
688         buf[rc] = '\0';
689         set_fs(old_fs);
690         if (rc < 0)
691                 goto out_free;
692         rc = 0;
693         nd_set_link(nd, buf);
694         goto out;
695 out_free:
696         kfree(buf);
697 out:
698         return ERR_PTR(rc);
699 }
700
701 static void
702 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
703 {
704         /* Free the char* */
705         kfree(nd_get_link(nd));
706 }
707
708 /**
709  * upper_size_to_lower_size
710  * @crypt_stat: Crypt_stat associated with file
711  * @upper_size: Size of the upper file
712  *
713  * Calculate the requried size of the lower file based on the
714  * specified size of the upper file. This calculation is based on the
715  * number of headers in the underlying file and the extent size.
716  *
717  * Returns Calculated size of the lower file.
718  */
719 static loff_t
720 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
721                          loff_t upper_size)
722 {
723         loff_t lower_size;
724
725         lower_size = ( crypt_stat->header_extent_size
726                        * crypt_stat->num_header_extents_at_front );
727         if (upper_size != 0) {
728                 loff_t num_extents;
729
730                 num_extents = upper_size >> crypt_stat->extent_shift;
731                 if (upper_size & ~crypt_stat->extent_mask)
732                         num_extents++;
733                 lower_size += (num_extents * crypt_stat->extent_size);
734         }
735         return lower_size;
736 }
737
738 /**
739  * ecryptfs_truncate
740  * @dentry: The ecryptfs layer dentry
741  * @new_length: The length to expand the file to
742  *
743  * Function to handle truncations modifying the size of the file. Note
744  * that the file sizes are interpolated. When expanding, we are simply
745  * writing strings of 0's out. When truncating, we need to modify the
746  * underlying file size according to the page index interpolations.
747  *
748  * Returns zero on success; non-zero otherwise
749  */
750 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
751 {
752         int rc = 0;
753         struct inode *inode = dentry->d_inode;
754         struct dentry *lower_dentry;
755         struct vfsmount *lower_mnt;
756         struct file fake_ecryptfs_file, *lower_file = NULL;
757         struct ecryptfs_crypt_stat *crypt_stat;
758         loff_t i_size = i_size_read(inode);
759         loff_t lower_size_before_truncate;
760         loff_t lower_size_after_truncate;
761
762         if (unlikely((new_length == i_size)))
763                 goto out;
764         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
765         /* Set up a fake ecryptfs file, this is used to interface with
766          * the file in the underlying filesystem so that the
767          * truncation has an effect there as well. */
768         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
769         fake_ecryptfs_file.f_path.dentry = dentry;
770         /* Released at out_free: label */
771         ecryptfs_set_file_private(&fake_ecryptfs_file,
772                                   kmem_cache_alloc(ecryptfs_file_info_cache,
773                                                    GFP_KERNEL));
774         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
775                 rc = -ENOMEM;
776                 goto out;
777         }
778         lower_dentry = ecryptfs_dentry_to_lower(dentry);
779         /* This dget & mntget is released through fput at out_fput: */
780         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
781         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
782                                            O_RDWR))) {
783                 ecryptfs_printk(KERN_ERR,
784                                 "Error opening dentry; rc = [%i]\n", rc);
785                 goto out_free;
786         }
787         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
788         /* Switch on growing or shrinking file */
789         if (new_length > i_size) {
790                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
791                 if (rc) {
792                         ecryptfs_printk(KERN_ERR,
793                                         "Problem with fill_zeros\n");
794                         goto out_fput;
795                 }
796                 i_size_write(inode, new_length);
797                 rc = ecryptfs_write_inode_size_to_metadata(
798                         lower_file, lower_dentry->d_inode, inode, dentry,
799                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
800                 if (rc) {
801                         printk(KERN_ERR "Problem with "
802                                "ecryptfs_write_inode_size_to_metadata; "
803                                "rc = [%d]\n", rc);
804                         goto out_fput;
805                 }
806         } else { /* new_length < i_size_read(inode) */
807                 pgoff_t index = 0;
808                 int end_pos_in_page = -1;
809
810                 if (new_length != 0) {
811                         index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
812                         end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
813                 }
814                 if (end_pos_in_page != (PAGE_CACHE_SIZE - 1)) {
815                         if ((rc = ecryptfs_write_zeros(&fake_ecryptfs_file,
816                                                        index,
817                                                        (end_pos_in_page + 1),
818                                                        ((PAGE_CACHE_SIZE - 1)
819                                                         - end_pos_in_page)))) {
820                                 printk(KERN_ERR "Error attempting to zero out "
821                                        "the remainder of the end page on "
822                                        "reducing truncate; rc = [%d]\n", rc);
823                                 goto out_fput;
824                         }
825                 }
826                 vmtruncate(inode, new_length);
827                 rc = ecryptfs_write_inode_size_to_metadata(
828                         lower_file, lower_dentry->d_inode, inode, dentry,
829                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
830                 if (rc) {
831                         printk(KERN_ERR "Problem with "
832                                "ecryptfs_write_inode_size_to_metadata; "
833                                "rc = [%d]\n", rc);
834                         goto out_fput;
835                 }
836                 /* We are reducing the size of the ecryptfs file, and need to
837                  * know if we need to reduce the size of the lower file. */
838                 lower_size_before_truncate =
839                     upper_size_to_lower_size(crypt_stat, i_size);
840                 lower_size_after_truncate =
841                     upper_size_to_lower_size(crypt_stat, new_length);
842                 if (lower_size_after_truncate < lower_size_before_truncate)
843                         vmtruncate(lower_dentry->d_inode,
844                                    lower_size_after_truncate);
845         }
846         /* Update the access times */
847         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
848                 = CURRENT_TIME;
849         mark_inode_dirty_sync(inode);
850 out_fput:
851         if ((rc = ecryptfs_close_lower_file(lower_file)))
852                 printk(KERN_ERR "Error closing lower_file\n");
853 out_free:
854         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
855                 kmem_cache_free(ecryptfs_file_info_cache,
856                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
857 out:
858         return rc;
859 }
860
861 static int
862 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
863 {
864         int rc;
865
866         if (nd) {
867                 struct vfsmount *vfsmnt_save = nd->mnt;
868                 struct dentry *dentry_save = nd->dentry;
869
870                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
871                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
872                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
873                 nd->mnt = vfsmnt_save;
874                 nd->dentry = dentry_save;
875         } else
876                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
877         return rc;
878 }
879
880 /**
881  * ecryptfs_setattr
882  * @dentry: dentry handle to the inode to modify
883  * @ia: Structure with flags of what to change and values
884  *
885  * Updates the metadata of an inode. If the update is to the size
886  * i.e. truncation, then ecryptfs_truncate will handle the size modification
887  * of both the ecryptfs inode and the lower inode.
888  *
889  * All other metadata changes will be passed right to the lower filesystem,
890  * and we will just update our inode to look like the lower.
891  */
892 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
893 {
894         int rc = 0;
895         struct dentry *lower_dentry;
896         struct inode *inode;
897         struct inode *lower_inode;
898         struct ecryptfs_crypt_stat *crypt_stat;
899
900         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
901         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
902                 ecryptfs_init_crypt_stat(crypt_stat);
903         inode = dentry->d_inode;
904         lower_inode = ecryptfs_inode_to_lower(inode);
905         lower_dentry = ecryptfs_dentry_to_lower(dentry);
906         mutex_lock(&crypt_stat->cs_mutex);
907         if (S_ISDIR(dentry->d_inode->i_mode))
908                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
909         else if (S_ISREG(dentry->d_inode->i_mode)
910                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
911                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
912                 struct vfsmount *lower_mnt;
913                 struct file *lower_file = NULL;
914                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
915                 int lower_flags;
916
917                 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
918                 lower_flags = O_RDONLY;
919                 if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
920                                                    lower_mnt, lower_flags))) {
921                         printk(KERN_ERR
922                                "Error opening lower file; rc = [%d]\n", rc);
923                         mutex_unlock(&crypt_stat->cs_mutex);
924                         goto out;
925                 }
926                 mount_crypt_stat = &ecryptfs_superblock_to_private(
927                         dentry->d_sb)->mount_crypt_stat;
928                 if ((rc = ecryptfs_read_metadata(dentry, lower_file))) {
929                         if (!(mount_crypt_stat->flags
930                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
931                                 rc = -EIO;
932                                 printk(KERN_WARNING "Attempt to read file that "
933                                        "is not in a valid eCryptfs format, "
934                                        "and plaintext passthrough mode is not "
935                                        "enabled; returning -EIO\n");
936
937                                 mutex_unlock(&crypt_stat->cs_mutex);
938                                 fput(lower_file);
939                                 goto out;
940                         }
941                         rc = 0;
942                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
943                         mutex_unlock(&crypt_stat->cs_mutex);
944                         fput(lower_file);
945                         goto out;
946                 }
947                 fput(lower_file);
948         }
949         mutex_unlock(&crypt_stat->cs_mutex);
950         if (ia->ia_valid & ATTR_SIZE) {
951                 ecryptfs_printk(KERN_DEBUG,
952                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
953                                 ia->ia_valid, ATTR_SIZE);
954                 rc = ecryptfs_truncate(dentry, ia->ia_size);
955                 /* ecryptfs_truncate handles resizing of the lower file */
956                 ia->ia_valid &= ~ATTR_SIZE;
957                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
958                                 ia->ia_valid);
959                 if (rc < 0)
960                         goto out;
961         }
962         rc = notify_change(lower_dentry, ia);
963 out:
964         fsstack_copy_attr_all(inode, lower_inode, NULL);
965         return rc;
966 }
967
968 int
969 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
970                   size_t size, int flags)
971 {
972         int rc = 0;
973         struct dentry *lower_dentry;
974
975         lower_dentry = ecryptfs_dentry_to_lower(dentry);
976         if (!lower_dentry->d_inode->i_op->setxattr) {
977                 rc = -ENOSYS;
978                 goto out;
979         }
980         mutex_lock(&lower_dentry->d_inode->i_mutex);
981         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
982                                                    size, flags);
983         mutex_unlock(&lower_dentry->d_inode->i_mutex);
984 out:
985         return rc;
986 }
987
988 ssize_t
989 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
990                   size_t size)
991 {
992         int rc = 0;
993         struct dentry *lower_dentry;
994
995         lower_dentry = ecryptfs_dentry_to_lower(dentry);
996         if (!lower_dentry->d_inode->i_op->getxattr) {
997                 rc = -ENOSYS;
998                 goto out;
999         }
1000         mutex_lock(&lower_dentry->d_inode->i_mutex);
1001         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1002                                                    size);
1003         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1004 out:
1005         return rc;
1006 }
1007
1008 static ssize_t
1009 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1010 {
1011         int rc = 0;
1012         struct dentry *lower_dentry;
1013
1014         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1015         if (!lower_dentry->d_inode->i_op->listxattr) {
1016                 rc = -ENOSYS;
1017                 goto out;
1018         }
1019         mutex_lock(&lower_dentry->d_inode->i_mutex);
1020         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1021         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1022 out:
1023         return rc;
1024 }
1025
1026 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1027 {
1028         int rc = 0;
1029         struct dentry *lower_dentry;
1030
1031         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1032         if (!lower_dentry->d_inode->i_op->removexattr) {
1033                 rc = -ENOSYS;
1034                 goto out;
1035         }
1036         mutex_lock(&lower_dentry->d_inode->i_mutex);
1037         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1038         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1039 out:
1040         return rc;
1041 }
1042
1043 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1044 {
1045         if ((ecryptfs_inode_to_lower(inode)
1046              == (struct inode *)candidate_lower_inode))
1047                 return 1;
1048         else
1049                 return 0;
1050 }
1051
1052 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1053 {
1054         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1055         return 0;
1056 }
1057
1058 const struct inode_operations ecryptfs_symlink_iops = {
1059         .readlink = ecryptfs_readlink,
1060         .follow_link = ecryptfs_follow_link,
1061         .put_link = ecryptfs_put_link,
1062         .permission = ecryptfs_permission,
1063         .setattr = ecryptfs_setattr,
1064         .setxattr = ecryptfs_setxattr,
1065         .getxattr = ecryptfs_getxattr,
1066         .listxattr = ecryptfs_listxattr,
1067         .removexattr = ecryptfs_removexattr
1068 };
1069
1070 const struct inode_operations ecryptfs_dir_iops = {
1071         .create = ecryptfs_create,
1072         .lookup = ecryptfs_lookup,
1073         .link = ecryptfs_link,
1074         .unlink = ecryptfs_unlink,
1075         .symlink = ecryptfs_symlink,
1076         .mkdir = ecryptfs_mkdir,
1077         .rmdir = ecryptfs_rmdir,
1078         .mknod = ecryptfs_mknod,
1079         .rename = ecryptfs_rename,
1080         .permission = ecryptfs_permission,
1081         .setattr = ecryptfs_setattr,
1082         .setxattr = ecryptfs_setxattr,
1083         .getxattr = ecryptfs_getxattr,
1084         .listxattr = ecryptfs_listxattr,
1085         .removexattr = ecryptfs_removexattr
1086 };
1087
1088 const struct inode_operations ecryptfs_main_iops = {
1089         .permission = ecryptfs_permission,
1090         .setattr = ecryptfs_setattr,
1091         .setxattr = ecryptfs_setxattr,
1092         .getxattr = ecryptfs_getxattr,
1093         .listxattr = ecryptfs_listxattr,
1094         .removexattr = ecryptfs_removexattr
1095 };