[PATCH] kill nameidata passing to permission(), rename to inode_permission()
[linux-2.6.git] / fs / ecryptfs / inode.c
1 /**
2  * eCryptfs: Linux filesystem encryption layer
3  *
4  * Copyright (C) 1997-2004 Erez Zadok
5  * Copyright (C) 2001-2004 Stony Brook University
6  * Copyright (C) 2004-2007 International Business Machines Corp.
7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation; either version 2 of the
13  * License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23  * 02111-1307, USA.
24  */
25
26 #include <linux/file.h>
27 #include <linux/vmalloc.h>
28 #include <linux/pagemap.h>
29 #include <linux/dcache.h>
30 #include <linux/namei.h>
31 #include <linux/mount.h>
32 #include <linux/crypto.h>
33 #include <linux/fs_stack.h>
34 #include <asm/unaligned.h>
35 #include "ecryptfs_kernel.h"
36
37 static struct dentry *lock_parent(struct dentry *dentry)
38 {
39         struct dentry *dir;
40
41         dir = dget_parent(dentry);
42         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
43         return dir;
44 }
45
46 static void unlock_dir(struct dentry *dir)
47 {
48         mutex_unlock(&dir->d_inode->i_mutex);
49         dput(dir);
50 }
51
52 /**
53  * ecryptfs_create_underlying_file
54  * @lower_dir_inode: inode of the parent in the lower fs of the new file
55  * @lower_dentry: New file's dentry in the lower fs
56  * @ecryptfs_dentry: New file's dentry in ecryptfs
57  * @mode: The mode of the new file
58  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
59  *
60  * Creates the file in the lower file system.
61  *
62  * Returns zero on success; non-zero on error condition
63  */
64 static int
65 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
66                                 struct dentry *dentry, int mode,
67                                 struct nameidata *nd)
68 {
69         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
70         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
71         struct dentry *dentry_save;
72         struct vfsmount *vfsmount_save;
73         int rc;
74
75         dentry_save = nd->path.dentry;
76         vfsmount_save = nd->path.mnt;
77         nd->path.dentry = lower_dentry;
78         nd->path.mnt = lower_mnt;
79         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
80         nd->path.dentry = dentry_save;
81         nd->path.mnt = vfsmount_save;
82         return rc;
83 }
84
85 /**
86  * ecryptfs_do_create
87  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
88  * @ecryptfs_dentry: New file's dentry in ecryptfs
89  * @mode: The mode of the new file
90  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
91  *
92  * Creates the underlying file and the eCryptfs inode which will link to
93  * it. It will also update the eCryptfs directory inode to mimic the
94  * stat of the lower directory inode.
95  *
96  * Returns zero on success; non-zero on error condition
97  */
98 static int
99 ecryptfs_do_create(struct inode *directory_inode,
100                    struct dentry *ecryptfs_dentry, int mode,
101                    struct nameidata *nd)
102 {
103         int rc;
104         struct dentry *lower_dentry;
105         struct dentry *lower_dir_dentry;
106
107         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
108         lower_dir_dentry = lock_parent(lower_dentry);
109         if (IS_ERR(lower_dir_dentry)) {
110                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
111                                 "dentry\n");
112                 rc = PTR_ERR(lower_dir_dentry);
113                 goto out;
114         }
115         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
116                                              ecryptfs_dentry, mode, nd);
117         if (rc) {
118                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
119                        "rc = [%d]\n", __func__, rc);
120                 goto out_lock;
121         }
122         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
123                                 directory_inode->i_sb, 0);
124         if (rc) {
125                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
126                 goto out_lock;
127         }
128         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
129         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
130 out_lock:
131         unlock_dir(lower_dir_dentry);
132 out:
133         return rc;
134 }
135
136 /**
137  * grow_file
138  * @ecryptfs_dentry: the eCryptfs dentry
139  *
140  * This is the code which will grow the file to its correct size.
141  */
142 static int grow_file(struct dentry *ecryptfs_dentry)
143 {
144         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
145         struct file fake_file;
146         struct ecryptfs_file_info tmp_file_info;
147         char zero_virt[] = { 0x00 };
148         int rc = 0;
149
150         memset(&fake_file, 0, sizeof(fake_file));
151         fake_file.f_path.dentry = ecryptfs_dentry;
152         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
153         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
154         ecryptfs_set_file_lower(
155                 &fake_file,
156                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
157         rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
158         i_size_write(ecryptfs_inode, 0);
159         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
160         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
161                 ECRYPTFS_NEW_FILE;
162         return rc;
163 }
164
165 /**
166  * ecryptfs_initialize_file
167  *
168  * Cause the file to be changed from a basic empty file to an ecryptfs
169  * file with a header and first data page.
170  *
171  * Returns zero on success
172  */
173 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
174 {
175         struct ecryptfs_crypt_stat *crypt_stat =
176                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
177         int rc = 0;
178
179         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
180                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
181                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
182                 goto out;
183         }
184         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
185         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
186         rc = ecryptfs_new_file_context(ecryptfs_dentry);
187         if (rc) {
188                 ecryptfs_printk(KERN_ERR, "Error creating new file "
189                                 "context; rc = [%d]\n", rc);
190                 goto out;
191         }
192         if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
193                 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
194                 if (rc) {
195                         printk(KERN_ERR "%s: Error attempting to initialize "
196                                "the persistent file for the dentry with name "
197                                "[%s]; rc = [%d]\n", __func__,
198                                ecryptfs_dentry->d_name.name, rc);
199                         goto out;
200                 }
201         }
202         rc = ecryptfs_write_metadata(ecryptfs_dentry);
203         if (rc) {
204                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
205                 goto out;
206         }
207         rc = grow_file(ecryptfs_dentry);
208         if (rc)
209                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
210 out:
211         return rc;
212 }
213
214 /**
215  * ecryptfs_create
216  * @dir: The inode of the directory in which to create the file.
217  * @dentry: The eCryptfs dentry
218  * @mode: The mode of the new file.
219  * @nd: nameidata
220  *
221  * Creates a new file.
222  *
223  * Returns zero on success; non-zero on error condition
224  */
225 static int
226 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
227                 int mode, struct nameidata *nd)
228 {
229         int rc;
230
231         /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
232          * the crypt_stat->lower_file (persistent file) */
233         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
234         if (unlikely(rc)) {
235                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
236                                 "lower filesystem\n");
237                 goto out;
238         }
239         /* At this point, a file exists on "disk"; we need to make sure
240          * that this on disk file is prepared to be an ecryptfs file */
241         rc = ecryptfs_initialize_file(ecryptfs_dentry);
242 out:
243         return rc;
244 }
245
246 /**
247  * ecryptfs_lookup
248  * @dir: inode
249  * @dentry: The dentry
250  * @nd: nameidata, may be NULL
251  *
252  * Find a file on disk. If the file does not exist, then we'll add it to the
253  * dentry cache and continue on to read it from the disk.
254  */
255 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
256                                       struct nameidata *nd)
257 {
258         int rc = 0;
259         struct dentry *lower_dir_dentry;
260         struct dentry *lower_dentry;
261         struct vfsmount *lower_mnt;
262         char *encoded_name;
263         int encoded_namelen;
264         struct ecryptfs_crypt_stat *crypt_stat = NULL;
265         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
266         char *page_virt = NULL;
267         struct inode *lower_inode;
268         u64 file_size;
269
270         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
271         dentry->d_op = &ecryptfs_dops;
272         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
273             || (dentry->d_name.len == 2
274                 && !strcmp(dentry->d_name.name, ".."))) {
275                 d_drop(dentry);
276                 goto out;
277         }
278         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
279                                                    dentry->d_name.name,
280                                                    dentry->d_name.len,
281                                                    &encoded_name);
282         if (encoded_namelen < 0) {
283                 rc = encoded_namelen;
284                 d_drop(dentry);
285                 goto out;
286         }
287         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
288                         "= [%d]\n", encoded_name, encoded_namelen);
289         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
290                                       encoded_namelen - 1);
291         kfree(encoded_name);
292         if (IS_ERR(lower_dentry)) {
293                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
294                 rc = PTR_ERR(lower_dentry);
295                 d_drop(dentry);
296                 goto out;
297         }
298         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
299         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
300                 "d_name.name = [%s]\n", lower_dentry,
301                 lower_dentry->d_name.name);
302         lower_inode = lower_dentry->d_inode;
303         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
304         BUG_ON(!atomic_read(&lower_dentry->d_count));
305         ecryptfs_set_dentry_private(dentry,
306                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
307                                                      GFP_KERNEL));
308         if (!ecryptfs_dentry_to_private(dentry)) {
309                 rc = -ENOMEM;
310                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
311                                 "to allocate ecryptfs_dentry_info struct\n");
312                 goto out_dput;
313         }
314         ecryptfs_set_dentry_lower(dentry, lower_dentry);
315         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
316         if (!lower_dentry->d_inode) {
317                 /* We want to add because we couldn't find in lower */
318                 d_add(dentry, NULL);
319                 goto out;
320         }
321         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb,
322                                 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
323         if (rc) {
324                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
325                 goto out;
326         }
327         if (S_ISDIR(lower_inode->i_mode)) {
328                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
329                 goto out;
330         }
331         if (S_ISLNK(lower_inode->i_mode)) {
332                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
333                 goto out;
334         }
335         if (special_file(lower_inode->i_mode)) {
336                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
337                 goto out;
338         }
339         if (!nd) {
340                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
341                                 "as we *think* we are about to unlink\n");
342                 goto out;
343         }
344         /* Released in this function */
345         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
346                                       GFP_USER);
347         if (!page_virt) {
348                 rc = -ENOMEM;
349                 ecryptfs_printk(KERN_ERR,
350                                 "Cannot ecryptfs_kmalloc a page\n");
351                 goto out;
352         }
353         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
354         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
355                 ecryptfs_set_default_sizes(crypt_stat);
356         if (!ecryptfs_inode_to_private(dentry->d_inode)->lower_file) {
357                 rc = ecryptfs_init_persistent_file(dentry);
358                 if (rc) {
359                         printk(KERN_ERR "%s: Error attempting to initialize "
360                                "the persistent file for the dentry with name "
361                                "[%s]; rc = [%d]\n", __func__,
362                                dentry->d_name.name, rc);
363                         goto out;
364                 }
365         }
366         rc = ecryptfs_read_and_validate_header_region(page_virt,
367                                                       dentry->d_inode);
368         if (rc) {
369                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
370                 if (rc) {
371                         printk(KERN_DEBUG "Valid metadata not found in header "
372                                "region or xattr region; treating file as "
373                                "unencrypted\n");
374                         rc = 0;
375                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
376                         goto out;
377                 }
378                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
379         }
380         mount_crypt_stat = &ecryptfs_superblock_to_private(
381                 dentry->d_sb)->mount_crypt_stat;
382         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
383                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
384                         file_size = (crypt_stat->num_header_bytes_at_front
385                                      + i_size_read(lower_dentry->d_inode));
386                 else
387                         file_size = i_size_read(lower_dentry->d_inode);
388         } else {
389                 file_size = get_unaligned_be64(page_virt);
390         }
391         i_size_write(dentry->d_inode, (loff_t)file_size);
392         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
393         goto out;
394
395 out_dput:
396         dput(lower_dentry);
397         d_drop(dentry);
398 out:
399         return ERR_PTR(rc);
400 }
401
402 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
403                          struct dentry *new_dentry)
404 {
405         struct dentry *lower_old_dentry;
406         struct dentry *lower_new_dentry;
407         struct dentry *lower_dir_dentry;
408         u64 file_size_save;
409         int rc;
410
411         file_size_save = i_size_read(old_dentry->d_inode);
412         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
413         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
414         dget(lower_old_dentry);
415         dget(lower_new_dentry);
416         lower_dir_dentry = lock_parent(lower_new_dentry);
417         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
418                       lower_new_dentry);
419         if (rc || !lower_new_dentry->d_inode)
420                 goto out_lock;
421         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
422         if (rc)
423                 goto out_lock;
424         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
425         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
426         old_dentry->d_inode->i_nlink =
427                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
428         i_size_write(new_dentry->d_inode, file_size_save);
429 out_lock:
430         unlock_dir(lower_dir_dentry);
431         dput(lower_new_dentry);
432         dput(lower_old_dentry);
433         d_drop(lower_old_dentry);
434         d_drop(new_dentry);
435         d_drop(old_dentry);
436         return rc;
437 }
438
439 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
440 {
441         int rc = 0;
442         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
443         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
444         struct dentry *lower_dir_dentry;
445
446         lower_dir_dentry = lock_parent(lower_dentry);
447         rc = vfs_unlink(lower_dir_inode, lower_dentry);
448         if (rc) {
449                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
450                 goto out_unlock;
451         }
452         fsstack_copy_attr_times(dir, lower_dir_inode);
453         dentry->d_inode->i_nlink =
454                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
455         dentry->d_inode->i_ctime = dir->i_ctime;
456         d_drop(dentry);
457 out_unlock:
458         unlock_dir(lower_dir_dentry);
459         return rc;
460 }
461
462 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
463                             const char *symname)
464 {
465         int rc;
466         struct dentry *lower_dentry;
467         struct dentry *lower_dir_dentry;
468         char *encoded_symname;
469         int encoded_symlen;
470         struct ecryptfs_crypt_stat *crypt_stat = NULL;
471
472         lower_dentry = ecryptfs_dentry_to_lower(dentry);
473         dget(lower_dentry);
474         lower_dir_dentry = lock_parent(lower_dentry);
475         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
476                                                   strlen(symname),
477                                                   &encoded_symname);
478         if (encoded_symlen < 0) {
479                 rc = encoded_symlen;
480                 goto out_lock;
481         }
482         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
483                          encoded_symname);
484         kfree(encoded_symname);
485         if (rc || !lower_dentry->d_inode)
486                 goto out_lock;
487         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
488         if (rc)
489                 goto out_lock;
490         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
491         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
492 out_lock:
493         unlock_dir(lower_dir_dentry);
494         dput(lower_dentry);
495         if (!dentry->d_inode)
496                 d_drop(dentry);
497         return rc;
498 }
499
500 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
501 {
502         int rc;
503         struct dentry *lower_dentry;
504         struct dentry *lower_dir_dentry;
505
506         lower_dentry = ecryptfs_dentry_to_lower(dentry);
507         lower_dir_dentry = lock_parent(lower_dentry);
508         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
509         if (rc || !lower_dentry->d_inode)
510                 goto out;
511         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
512         if (rc)
513                 goto out;
514         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
515         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
516         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
517 out:
518         unlock_dir(lower_dir_dentry);
519         if (!dentry->d_inode)
520                 d_drop(dentry);
521         return rc;
522 }
523
524 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
525 {
526         struct dentry *lower_dentry;
527         struct dentry *lower_dir_dentry;
528         int rc;
529
530         lower_dentry = ecryptfs_dentry_to_lower(dentry);
531         dget(dentry);
532         lower_dir_dentry = lock_parent(lower_dentry);
533         dget(lower_dentry);
534         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
535         dput(lower_dentry);
536         if (!rc)
537                 d_delete(lower_dentry);
538         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
539         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
540         unlock_dir(lower_dir_dentry);
541         if (!rc)
542                 d_drop(dentry);
543         dput(dentry);
544         return rc;
545 }
546
547 static int
548 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
549 {
550         int rc;
551         struct dentry *lower_dentry;
552         struct dentry *lower_dir_dentry;
553
554         lower_dentry = ecryptfs_dentry_to_lower(dentry);
555         lower_dir_dentry = lock_parent(lower_dentry);
556         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
557         if (rc || !lower_dentry->d_inode)
558                 goto out;
559         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
560         if (rc)
561                 goto out;
562         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
563         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
564 out:
565         unlock_dir(lower_dir_dentry);
566         if (!dentry->d_inode)
567                 d_drop(dentry);
568         return rc;
569 }
570
571 static int
572 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
573                 struct inode *new_dir, struct dentry *new_dentry)
574 {
575         int rc;
576         struct dentry *lower_old_dentry;
577         struct dentry *lower_new_dentry;
578         struct dentry *lower_old_dir_dentry;
579         struct dentry *lower_new_dir_dentry;
580
581         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
582         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
583         dget(lower_old_dentry);
584         dget(lower_new_dentry);
585         lower_old_dir_dentry = dget_parent(lower_old_dentry);
586         lower_new_dir_dentry = dget_parent(lower_new_dentry);
587         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
588         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
589                         lower_new_dir_dentry->d_inode, lower_new_dentry);
590         if (rc)
591                 goto out_lock;
592         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
593         if (new_dir != old_dir)
594                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
595 out_lock:
596         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
597         dput(lower_new_dentry->d_parent);
598         dput(lower_old_dentry->d_parent);
599         dput(lower_new_dentry);
600         dput(lower_old_dentry);
601         return rc;
602 }
603
604 static int
605 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
606 {
607         int rc;
608         struct dentry *lower_dentry;
609         char *decoded_name;
610         char *lower_buf;
611         mm_segment_t old_fs;
612         struct ecryptfs_crypt_stat *crypt_stat;
613
614         lower_dentry = ecryptfs_dentry_to_lower(dentry);
615         if (!lower_dentry->d_inode->i_op ||
616             !lower_dentry->d_inode->i_op->readlink) {
617                 rc = -EINVAL;
618                 goto out;
619         }
620         /* Released in this function */
621         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
622         if (lower_buf == NULL) {
623                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
624                 rc = -ENOMEM;
625                 goto out;
626         }
627         old_fs = get_fs();
628         set_fs(get_ds());
629         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
630                         "lower_dentry->d_name.name = [%s]\n",
631                         lower_dentry->d_name.name);
632         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
633                                                    (char __user *)lower_buf,
634                                                    bufsiz);
635         set_fs(old_fs);
636         if (rc >= 0) {
637                 crypt_stat = NULL;
638                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
639                                               &decoded_name);
640                 if (rc == -ENOMEM)
641                         goto out_free_lower_buf;
642                 if (rc > 0) {
643                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
644                                         "to userspace: [%*s]\n", rc,
645                                         decoded_name);
646                         if (copy_to_user(buf, decoded_name, rc))
647                                 rc = -EFAULT;
648                 }
649                 kfree(decoded_name);
650                 fsstack_copy_attr_atime(dentry->d_inode,
651                                         lower_dentry->d_inode);
652         }
653 out_free_lower_buf:
654         kfree(lower_buf);
655 out:
656         return rc;
657 }
658
659 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
660 {
661         char *buf;
662         int len = PAGE_SIZE, rc;
663         mm_segment_t old_fs;
664
665         /* Released in ecryptfs_put_link(); only release here on error */
666         buf = kmalloc(len, GFP_KERNEL);
667         if (!buf) {
668                 rc = -ENOMEM;
669                 goto out;
670         }
671         old_fs = get_fs();
672         set_fs(get_ds());
673         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
674                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
675         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
676         buf[rc] = '\0';
677         set_fs(old_fs);
678         if (rc < 0)
679                 goto out_free;
680         rc = 0;
681         nd_set_link(nd, buf);
682         goto out;
683 out_free:
684         kfree(buf);
685 out:
686         return ERR_PTR(rc);
687 }
688
689 static void
690 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
691 {
692         /* Free the char* */
693         kfree(nd_get_link(nd));
694 }
695
696 /**
697  * upper_size_to_lower_size
698  * @crypt_stat: Crypt_stat associated with file
699  * @upper_size: Size of the upper file
700  *
701  * Calculate the required size of the lower file based on the
702  * specified size of the upper file. This calculation is based on the
703  * number of headers in the underlying file and the extent size.
704  *
705  * Returns Calculated size of the lower file.
706  */
707 static loff_t
708 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
709                          loff_t upper_size)
710 {
711         loff_t lower_size;
712
713         lower_size = crypt_stat->num_header_bytes_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)
832 {
833         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
834 }
835
836 /**
837  * ecryptfs_setattr
838  * @dentry: dentry handle to the inode to modify
839  * @ia: Structure with flags of what to change and values
840  *
841  * Updates the metadata of an inode. If the update is to the size
842  * i.e. truncation, then ecryptfs_truncate will handle the size modification
843  * of both the ecryptfs inode and the lower inode.
844  *
845  * All other metadata changes will be passed right to the lower filesystem,
846  * and we will just update our inode to look like the lower.
847  */
848 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
849 {
850         int rc = 0;
851         struct dentry *lower_dentry;
852         struct inode *inode;
853         struct inode *lower_inode;
854         struct ecryptfs_crypt_stat *crypt_stat;
855
856         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
857         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
858                 ecryptfs_init_crypt_stat(crypt_stat);
859         inode = dentry->d_inode;
860         lower_inode = ecryptfs_inode_to_lower(inode);
861         lower_dentry = ecryptfs_dentry_to_lower(dentry);
862         mutex_lock(&crypt_stat->cs_mutex);
863         if (S_ISDIR(dentry->d_inode->i_mode))
864                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
865         else if (S_ISREG(dentry->d_inode->i_mode)
866                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
867                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
868                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
869
870                 mount_crypt_stat = &ecryptfs_superblock_to_private(
871                         dentry->d_sb)->mount_crypt_stat;
872                 rc = ecryptfs_read_metadata(dentry);
873                 if (rc) {
874                         if (!(mount_crypt_stat->flags
875                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
876                                 rc = -EIO;
877                                 printk(KERN_WARNING "Either the lower file "
878                                        "is not in a valid eCryptfs format, "
879                                        "or the key could not be retrieved. "
880                                        "Plaintext passthrough mode is not "
881                                        "enabled; returning -EIO\n");
882                                 mutex_unlock(&crypt_stat->cs_mutex);
883                                 goto out;
884                         }
885                         rc = 0;
886                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
887                         mutex_unlock(&crypt_stat->cs_mutex);
888                         goto out;
889                 }
890         }
891         mutex_unlock(&crypt_stat->cs_mutex);
892         if (ia->ia_valid & ATTR_SIZE) {
893                 ecryptfs_printk(KERN_DEBUG,
894                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
895                                 ia->ia_valid, ATTR_SIZE);
896                 rc = ecryptfs_truncate(dentry, ia->ia_size);
897                 /* ecryptfs_truncate handles resizing of the lower file */
898                 ia->ia_valid &= ~ATTR_SIZE;
899                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
900                                 ia->ia_valid);
901                 if (rc < 0)
902                         goto out;
903         }
904
905         /*
906          * mode change is for clearing setuid/setgid bits. Allow lower fs
907          * to interpret this in its own way.
908          */
909         if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
910                 ia->ia_valid &= ~ATTR_MODE;
911
912         mutex_lock(&lower_dentry->d_inode->i_mutex);
913         rc = notify_change(lower_dentry, ia);
914         mutex_unlock(&lower_dentry->d_inode->i_mutex);
915 out:
916         fsstack_copy_attr_all(inode, lower_inode, NULL);
917         return rc;
918 }
919
920 int
921 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
922                   size_t size, int flags)
923 {
924         int rc = 0;
925         struct dentry *lower_dentry;
926
927         lower_dentry = ecryptfs_dentry_to_lower(dentry);
928         if (!lower_dentry->d_inode->i_op->setxattr) {
929                 rc = -ENOSYS;
930                 goto out;
931         }
932         mutex_lock(&lower_dentry->d_inode->i_mutex);
933         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
934                                                    size, flags);
935         mutex_unlock(&lower_dentry->d_inode->i_mutex);
936 out:
937         return rc;
938 }
939
940 ssize_t
941 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
942                         void *value, size_t size)
943 {
944         int rc = 0;
945
946         if (!lower_dentry->d_inode->i_op->getxattr) {
947                 rc = -ENOSYS;
948                 goto out;
949         }
950         mutex_lock(&lower_dentry->d_inode->i_mutex);
951         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
952                                                    size);
953         mutex_unlock(&lower_dentry->d_inode->i_mutex);
954 out:
955         return rc;
956 }
957
958 static ssize_t
959 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
960                   size_t size)
961 {
962         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
963                                        value, size);
964 }
965
966 static ssize_t
967 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
968 {
969         int rc = 0;
970         struct dentry *lower_dentry;
971
972         lower_dentry = ecryptfs_dentry_to_lower(dentry);
973         if (!lower_dentry->d_inode->i_op->listxattr) {
974                 rc = -ENOSYS;
975                 goto out;
976         }
977         mutex_lock(&lower_dentry->d_inode->i_mutex);
978         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
979         mutex_unlock(&lower_dentry->d_inode->i_mutex);
980 out:
981         return rc;
982 }
983
984 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
985 {
986         int rc = 0;
987         struct dentry *lower_dentry;
988
989         lower_dentry = ecryptfs_dentry_to_lower(dentry);
990         if (!lower_dentry->d_inode->i_op->removexattr) {
991                 rc = -ENOSYS;
992                 goto out;
993         }
994         mutex_lock(&lower_dentry->d_inode->i_mutex);
995         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
996         mutex_unlock(&lower_dentry->d_inode->i_mutex);
997 out:
998         return rc;
999 }
1000
1001 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1002 {
1003         if ((ecryptfs_inode_to_lower(inode)
1004              == (struct inode *)candidate_lower_inode))
1005                 return 1;
1006         else
1007                 return 0;
1008 }
1009
1010 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1011 {
1012         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1013         return 0;
1014 }
1015
1016 const struct inode_operations ecryptfs_symlink_iops = {
1017         .readlink = ecryptfs_readlink,
1018         .follow_link = ecryptfs_follow_link,
1019         .put_link = ecryptfs_put_link,
1020         .permission = ecryptfs_permission,
1021         .setattr = ecryptfs_setattr,
1022         .setxattr = ecryptfs_setxattr,
1023         .getxattr = ecryptfs_getxattr,
1024         .listxattr = ecryptfs_listxattr,
1025         .removexattr = ecryptfs_removexattr
1026 };
1027
1028 const struct inode_operations ecryptfs_dir_iops = {
1029         .create = ecryptfs_create,
1030         .lookup = ecryptfs_lookup,
1031         .link = ecryptfs_link,
1032         .unlink = ecryptfs_unlink,
1033         .symlink = ecryptfs_symlink,
1034         .mkdir = ecryptfs_mkdir,
1035         .rmdir = ecryptfs_rmdir,
1036         .mknod = ecryptfs_mknod,
1037         .rename = ecryptfs_rename,
1038         .permission = ecryptfs_permission,
1039         .setattr = ecryptfs_setattr,
1040         .setxattr = ecryptfs_setxattr,
1041         .getxattr = ecryptfs_getxattr,
1042         .listxattr = ecryptfs_listxattr,
1043         .removexattr = ecryptfs_removexattr
1044 };
1045
1046 const struct inode_operations ecryptfs_main_iops = {
1047         .permission = ecryptfs_permission,
1048         .setattr = ecryptfs_setattr,
1049         .setxattr = ecryptfs_setxattr,
1050         .getxattr = ecryptfs_getxattr,
1051         .listxattr = ecryptfs_listxattr,
1052         .removexattr = ecryptfs_removexattr
1053 };