88ba4d43299a4d50334f64a93317785508e8bb2e
[firefly-linux-kernel-4.4.55.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  * @dentry: New file's dentry
56  * @mode: The mode of the new file
57  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
58  *
59  * Creates the file in the lower file system.
60  *
61  * Returns zero on success; non-zero on error condition
62  */
63 static int
64 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
65                                 struct dentry *dentry, int mode,
66                                 struct nameidata *nd)
67 {
68         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
69         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
70         struct dentry *dentry_save;
71         struct vfsmount *vfsmount_save;
72         unsigned int flags_save;
73         int rc;
74
75         dentry_save = nd->path.dentry;
76         vfsmount_save = nd->path.mnt;
77         flags_save = nd->flags;
78         nd->path.dentry = lower_dentry;
79         nd->path.mnt = lower_mnt;
80         nd->flags &= ~LOOKUP_OPEN;
81         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
82         nd->path.dentry = dentry_save;
83         nd->path.mnt = vfsmount_save;
84         nd->flags = flags_save;
85         return rc;
86 }
87
88 /**
89  * ecryptfs_do_create
90  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
91  * @ecryptfs_dentry: New file's dentry in ecryptfs
92  * @mode: The mode of the new file
93  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
94  *
95  * Creates the underlying file and the eCryptfs inode which will link to
96  * it. It will also update the eCryptfs directory inode to mimic the
97  * stat of the lower directory inode.
98  *
99  * Returns zero on success; non-zero on error condition
100  */
101 static int
102 ecryptfs_do_create(struct inode *directory_inode,
103                    struct dentry *ecryptfs_dentry, int mode,
104                    struct nameidata *nd)
105 {
106         int rc;
107         struct dentry *lower_dentry;
108         struct dentry *lower_dir_dentry;
109
110         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
111         lower_dir_dentry = lock_parent(lower_dentry);
112         if (IS_ERR(lower_dir_dentry)) {
113                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
114                                 "dentry\n");
115                 rc = PTR_ERR(lower_dir_dentry);
116                 goto out;
117         }
118         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
119                                              ecryptfs_dentry, mode, nd);
120         if (rc) {
121                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
122                        "rc = [%d]\n", __func__, rc);
123                 goto out_lock;
124         }
125         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
126                                 directory_inode->i_sb, 0);
127         if (rc) {
128                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
129                 goto out_lock;
130         }
131         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
132         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
133 out_lock:
134         unlock_dir(lower_dir_dentry);
135 out:
136         return rc;
137 }
138
139 /**
140  * grow_file
141  * @ecryptfs_dentry: the eCryptfs dentry
142  *
143  * This is the code which will grow the file to its correct size.
144  */
145 static int grow_file(struct dentry *ecryptfs_dentry)
146 {
147         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
148         struct file fake_file;
149         struct ecryptfs_file_info tmp_file_info;
150         char zero_virt[] = { 0x00 };
151         int rc = 0;
152
153         memset(&fake_file, 0, sizeof(fake_file));
154         fake_file.f_path.dentry = ecryptfs_dentry;
155         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
156         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
157         ecryptfs_set_file_lower(
158                 &fake_file,
159                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
160         rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
161         i_size_write(ecryptfs_inode, 0);
162         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
163         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
164                 ECRYPTFS_NEW_FILE;
165         return rc;
166 }
167
168 /**
169  * ecryptfs_initialize_file
170  *
171  * Cause the file to be changed from a basic empty file to an ecryptfs
172  * file with a header and first data page.
173  *
174  * Returns zero on success
175  */
176 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
177 {
178         struct ecryptfs_crypt_stat *crypt_stat =
179                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
180         int rc = 0;
181
182         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
183                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
184                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
185                 goto out;
186         }
187         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
188         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
189         rc = ecryptfs_new_file_context(ecryptfs_dentry);
190         if (rc) {
191                 ecryptfs_printk(KERN_ERR, "Error creating new file "
192                                 "context; rc = [%d]\n", rc);
193                 goto out;
194         }
195         if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
196                 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
197                 if (rc) {
198                         printk(KERN_ERR "%s: Error attempting to initialize "
199                                "the persistent file for the dentry with name "
200                                "[%s]; rc = [%d]\n", __func__,
201                                ecryptfs_dentry->d_name.name, rc);
202                         goto out;
203                 }
204         }
205         rc = ecryptfs_write_metadata(ecryptfs_dentry);
206         if (rc) {
207                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
208                 goto out;
209         }
210         rc = grow_file(ecryptfs_dentry);
211         if (rc)
212                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
213 out:
214         return rc;
215 }
216
217 /**
218  * ecryptfs_create
219  * @dir: The inode of the directory in which to create the file.
220  * @dentry: The eCryptfs dentry
221  * @mode: The mode of the new file.
222  * @nd: nameidata
223  *
224  * Creates a new file.
225  *
226  * Returns zero on success; non-zero on error condition
227  */
228 static int
229 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
230                 int mode, struct nameidata *nd)
231 {
232         int rc;
233
234         /* ecryptfs_do_create() calls ecryptfs_interpose() */
235         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
236         if (unlikely(rc)) {
237                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
238                                 "lower filesystem\n");
239                 goto out;
240         }
241         /* At this point, a file exists on "disk"; we need to make sure
242          * that this on disk file is prepared to be an ecryptfs file */
243         rc = ecryptfs_initialize_file(ecryptfs_dentry);
244 out:
245         return rc;
246 }
247
248 /**
249  * ecryptfs_lookup_and_interpose_lower - Perform a lookup
250  */
251 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
252                                         struct dentry *lower_dentry,
253                                         struct inode *ecryptfs_dir_inode,
254                                         struct nameidata *ecryptfs_nd)
255 {
256         struct dentry *lower_dir_dentry;
257         struct vfsmount *lower_mnt;
258         struct inode *lower_inode;
259         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
260         struct ecryptfs_crypt_stat *crypt_stat;
261         char *page_virt = NULL;
262         u64 file_size;
263         int rc = 0;
264
265         lower_dir_dentry = lower_dentry->d_parent;
266         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
267                                    ecryptfs_dentry->d_parent));
268         lower_inode = lower_dentry->d_inode;
269         fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
270         BUG_ON(!atomic_read(&lower_dentry->d_count));
271         ecryptfs_set_dentry_private(ecryptfs_dentry,
272                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
273                                                      GFP_KERNEL));
274         if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
275                 rc = -ENOMEM;
276                 printk(KERN_ERR "%s: Out of memory whilst attempting "
277                        "to allocate ecryptfs_dentry_info struct\n",
278                         __func__);
279                 goto out_put;
280         }
281         ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
282         ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
283         if (!lower_dentry->d_inode) {
284                 /* We want to add because we couldn't find in lower */
285                 d_add(ecryptfs_dentry, NULL);
286                 goto out;
287         }
288         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
289                                 ecryptfs_dir_inode->i_sb, 1);
290         if (rc) {
291                 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
292                        __func__, rc);
293                 goto out;
294         }
295         if (S_ISDIR(lower_inode->i_mode))
296                 goto out;
297         if (S_ISLNK(lower_inode->i_mode))
298                 goto out;
299         if (special_file(lower_inode->i_mode))
300                 goto out;
301         if (!ecryptfs_nd)
302                 goto out;
303         /* Released in this function */
304         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
305         if (!page_virt) {
306                 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
307                        __func__);
308                 rc = -ENOMEM;
309                 goto out;
310         }
311         if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
312                 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
313                 if (rc) {
314                         printk(KERN_ERR "%s: Error attempting to initialize "
315                                "the persistent file for the dentry with name "
316                                "[%s]; rc = [%d]\n", __func__,
317                                ecryptfs_dentry->d_name.name, rc);
318                         goto out_free_kmem;
319                 }
320         }
321         crypt_stat = &ecryptfs_inode_to_private(
322                                         ecryptfs_dentry->d_inode)->crypt_stat;
323         /* TODO: lock for crypt_stat comparison */
324         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
325                         ecryptfs_set_default_sizes(crypt_stat);
326         rc = ecryptfs_read_and_validate_header_region(page_virt,
327                                                       ecryptfs_dentry->d_inode);
328         if (rc) {
329                 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
330                                                              ecryptfs_dentry);
331                 if (rc) {
332                         rc = 0;
333                         goto out_free_kmem;
334                 }
335                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
336         }
337         mount_crypt_stat = &ecryptfs_superblock_to_private(
338                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
339         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
340                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
341                         file_size = (crypt_stat->num_header_bytes_at_front
342                                      + i_size_read(lower_dentry->d_inode));
343                 else
344                         file_size = i_size_read(lower_dentry->d_inode);
345         } else {
346                 file_size = get_unaligned_be64(page_virt);
347         }
348         i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
349 out_free_kmem:
350         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
351         goto out;
352 out_put:
353         dput(lower_dentry);
354         mntput(lower_mnt);
355         d_drop(ecryptfs_dentry);
356 out:
357         return rc;
358 }
359
360 /**
361  * ecryptfs_lookup
362  * @ecryptfs_dir_inode: The eCryptfs directory inode
363  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
364  * @ecryptfs_nd: nameidata; may be NULL
365  *
366  * Find a file on disk. If the file does not exist, then we'll add it to the
367  * dentry cache and continue on to read it from the disk.
368  */
369 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
370                                       struct dentry *ecryptfs_dentry,
371                                       struct nameidata *ecryptfs_nd)
372 {
373         char *encrypted_and_encoded_name = NULL;
374         size_t encrypted_and_encoded_name_size;
375         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
376         struct dentry *lower_dir_dentry, *lower_dentry;
377         int rc = 0;
378
379         ecryptfs_dentry->d_op = &ecryptfs_dops;
380         if ((ecryptfs_dentry->d_name.len == 1
381              && !strcmp(ecryptfs_dentry->d_name.name, "."))
382             || (ecryptfs_dentry->d_name.len == 2
383                 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
384                 goto out_d_drop;
385         }
386         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
387         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
388         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
389                                       lower_dir_dentry,
390                                       ecryptfs_dentry->d_name.len);
391         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
392         if (IS_ERR(lower_dentry)) {
393                 rc = PTR_ERR(lower_dentry);
394                 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
395                        "lower_dentry = [%s]\n", __func__, rc,
396                        ecryptfs_dentry->d_name.name);
397                 goto out_d_drop;
398         }
399         if (lower_dentry->d_inode)
400                 goto lookup_and_interpose;
401         mount_crypt_stat = &ecryptfs_superblock_to_private(
402                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
403         if (!(mount_crypt_stat
404             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
405                 goto lookup_and_interpose;
406         dput(lower_dentry);
407         rc = ecryptfs_encrypt_and_encode_filename(
408                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
409                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
410                 ecryptfs_dentry->d_name.len);
411         if (rc) {
412                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
413                        "filename; rc = [%d]\n", __func__, rc);
414                 goto out_d_drop;
415         }
416         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
417         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
418                                       lower_dir_dentry,
419                                       encrypted_and_encoded_name_size - 1);
420         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
421         if (IS_ERR(lower_dentry)) {
422                 rc = PTR_ERR(lower_dentry);
423                 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
424                        "lower_dentry = [%s]\n", __func__, rc,
425                        encrypted_and_encoded_name);
426                 goto out_d_drop;
427         }
428 lookup_and_interpose:
429         rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
430                                                  ecryptfs_dir_inode,
431                                                  ecryptfs_nd);
432         goto out;
433 out_d_drop:
434         d_drop(ecryptfs_dentry);
435 out:
436         kfree(encrypted_and_encoded_name);
437         return ERR_PTR(rc);
438 }
439
440 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
441                          struct dentry *new_dentry)
442 {
443         struct dentry *lower_old_dentry;
444         struct dentry *lower_new_dentry;
445         struct dentry *lower_dir_dentry;
446         u64 file_size_save;
447         int rc;
448
449         file_size_save = i_size_read(old_dentry->d_inode);
450         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
451         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
452         dget(lower_old_dentry);
453         dget(lower_new_dentry);
454         lower_dir_dentry = lock_parent(lower_new_dentry);
455         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
456                       lower_new_dentry);
457         if (rc || !lower_new_dentry->d_inode)
458                 goto out_lock;
459         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
460         if (rc)
461                 goto out_lock;
462         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
463         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
464         old_dentry->d_inode->i_nlink =
465                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
466         i_size_write(new_dentry->d_inode, file_size_save);
467 out_lock:
468         unlock_dir(lower_dir_dentry);
469         dput(lower_new_dentry);
470         dput(lower_old_dentry);
471         d_drop(lower_old_dentry);
472         d_drop(new_dentry);
473         d_drop(old_dentry);
474         return rc;
475 }
476
477 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
478 {
479         int rc = 0;
480         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
481         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
482         struct dentry *lower_dir_dentry;
483
484         dget(lower_dentry);
485         lower_dir_dentry = lock_parent(lower_dentry);
486         rc = vfs_unlink(lower_dir_inode, lower_dentry);
487         if (rc) {
488                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
489                 goto out_unlock;
490         }
491         fsstack_copy_attr_times(dir, lower_dir_inode);
492         dentry->d_inode->i_nlink =
493                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
494         dentry->d_inode->i_ctime = dir->i_ctime;
495         d_drop(dentry);
496 out_unlock:
497         unlock_dir(lower_dir_dentry);
498         dput(lower_dentry);
499         return rc;
500 }
501
502 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
503                             const char *symname)
504 {
505         int rc;
506         struct dentry *lower_dentry;
507         struct dentry *lower_dir_dentry;
508         char *encoded_symname;
509         size_t encoded_symlen;
510         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
511
512         lower_dentry = ecryptfs_dentry_to_lower(dentry);
513         dget(lower_dentry);
514         lower_dir_dentry = lock_parent(lower_dentry);
515         mount_crypt_stat = &ecryptfs_superblock_to_private(
516                 dir->i_sb)->mount_crypt_stat;
517         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
518                                                   &encoded_symlen,
519                                                   NULL,
520                                                   mount_crypt_stat, symname,
521                                                   strlen(symname));
522         if (rc)
523                 goto out_lock;
524         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
525                          encoded_symname);
526         kfree(encoded_symname);
527         if (rc || !lower_dentry->d_inode)
528                 goto out_lock;
529         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
530         if (rc)
531                 goto out_lock;
532         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
533         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
534 out_lock:
535         unlock_dir(lower_dir_dentry);
536         dput(lower_dentry);
537         if (!dentry->d_inode)
538                 d_drop(dentry);
539         return rc;
540 }
541
542 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
543 {
544         int rc;
545         struct dentry *lower_dentry;
546         struct dentry *lower_dir_dentry;
547
548         lower_dentry = ecryptfs_dentry_to_lower(dentry);
549         lower_dir_dentry = lock_parent(lower_dentry);
550         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
551         if (rc || !lower_dentry->d_inode)
552                 goto out;
553         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
554         if (rc)
555                 goto out;
556         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
557         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
558         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
559 out:
560         unlock_dir(lower_dir_dentry);
561         if (!dentry->d_inode)
562                 d_drop(dentry);
563         return rc;
564 }
565
566 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
567 {
568         struct dentry *lower_dentry;
569         struct dentry *lower_dir_dentry;
570         int rc;
571
572         lower_dentry = ecryptfs_dentry_to_lower(dentry);
573         dget(dentry);
574         lower_dir_dentry = lock_parent(lower_dentry);
575         dget(lower_dentry);
576         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
577         dput(lower_dentry);
578         if (!rc)
579                 d_delete(lower_dentry);
580         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
581         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
582         unlock_dir(lower_dir_dentry);
583         if (!rc)
584                 d_drop(dentry);
585         dput(dentry);
586         return rc;
587 }
588
589 static int
590 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
591 {
592         int rc;
593         struct dentry *lower_dentry;
594         struct dentry *lower_dir_dentry;
595
596         lower_dentry = ecryptfs_dentry_to_lower(dentry);
597         lower_dir_dentry = lock_parent(lower_dentry);
598         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
599         if (rc || !lower_dentry->d_inode)
600                 goto out;
601         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
602         if (rc)
603                 goto out;
604         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
605         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
606 out:
607         unlock_dir(lower_dir_dentry);
608         if (!dentry->d_inode)
609                 d_drop(dentry);
610         return rc;
611 }
612
613 static int
614 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
615                 struct inode *new_dir, struct dentry *new_dentry)
616 {
617         int rc;
618         struct dentry *lower_old_dentry;
619         struct dentry *lower_new_dentry;
620         struct dentry *lower_old_dir_dentry;
621         struct dentry *lower_new_dir_dentry;
622
623         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
624         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
625         dget(lower_old_dentry);
626         dget(lower_new_dentry);
627         lower_old_dir_dentry = dget_parent(lower_old_dentry);
628         lower_new_dir_dentry = dget_parent(lower_new_dentry);
629         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
630         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
631                         lower_new_dir_dentry->d_inode, lower_new_dentry);
632         if (rc)
633                 goto out_lock;
634         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
635         if (new_dir != old_dir)
636                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
637 out_lock:
638         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
639         dput(lower_new_dentry->d_parent);
640         dput(lower_old_dentry->d_parent);
641         dput(lower_new_dentry);
642         dput(lower_old_dentry);
643         return rc;
644 }
645
646 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
647                                    size_t *bufsiz)
648 {
649         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
650         char *lower_buf;
651         size_t lower_bufsiz = PATH_MAX;
652         mm_segment_t old_fs;
653         int rc;
654
655         lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
656         if (!lower_buf) {
657                 rc = -ENOMEM;
658                 goto out;
659         }
660         old_fs = get_fs();
661         set_fs(get_ds());
662         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
663                                                    (char __user *)lower_buf,
664                                                    lower_bufsiz);
665         set_fs(old_fs);
666         if (rc < 0)
667                 goto out;
668         lower_bufsiz = rc;
669         rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
670                                                   lower_buf, lower_bufsiz);
671 out:
672         kfree(lower_buf);
673         return rc;
674 }
675
676 static int
677 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
678 {
679         char *kbuf;
680         size_t kbufsiz, copied;
681         int rc;
682
683         rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
684         if (rc)
685                 goto out;
686         copied = min_t(size_t, bufsiz, kbufsiz);
687         rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
688         kfree(kbuf);
689         fsstack_copy_attr_atime(dentry->d_inode,
690                                 ecryptfs_dentry_to_lower(dentry)->d_inode);
691 out:
692         return rc;
693 }
694
695 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
696 {
697         char *buf;
698         int len = PAGE_SIZE, rc;
699         mm_segment_t old_fs;
700
701         /* Released in ecryptfs_put_link(); only release here on error */
702         buf = kmalloc(len, GFP_KERNEL);
703         if (!buf) {
704                 rc = -ENOMEM;
705                 goto out;
706         }
707         old_fs = get_fs();
708         set_fs(get_ds());
709         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
710         set_fs(old_fs);
711         if (rc < 0)
712                 goto out_free;
713         else
714                 buf[rc] = '\0';
715         rc = 0;
716         nd_set_link(nd, buf);
717         goto out;
718 out_free:
719         kfree(buf);
720 out:
721         return ERR_PTR(rc);
722 }
723
724 static void
725 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
726 {
727         /* Free the char* */
728         kfree(nd_get_link(nd));
729 }
730
731 /**
732  * upper_size_to_lower_size
733  * @crypt_stat: Crypt_stat associated with file
734  * @upper_size: Size of the upper file
735  *
736  * Calculate the required size of the lower file based on the
737  * specified size of the upper file. This calculation is based on the
738  * number of headers in the underlying file and the extent size.
739  *
740  * Returns Calculated size of the lower file.
741  */
742 static loff_t
743 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
744                          loff_t upper_size)
745 {
746         loff_t lower_size;
747
748         lower_size = crypt_stat->num_header_bytes_at_front;
749         if (upper_size != 0) {
750                 loff_t num_extents;
751
752                 num_extents = upper_size >> crypt_stat->extent_shift;
753                 if (upper_size & ~crypt_stat->extent_mask)
754                         num_extents++;
755                 lower_size += (num_extents * crypt_stat->extent_size);
756         }
757         return lower_size;
758 }
759
760 /**
761  * ecryptfs_truncate
762  * @dentry: The ecryptfs layer dentry
763  * @new_length: The length to expand the file to
764  *
765  * Function to handle truncations modifying the size of the file. Note
766  * that the file sizes are interpolated. When expanding, we are simply
767  * writing strings of 0's out. When truncating, we need to modify the
768  * underlying file size according to the page index interpolations.
769  *
770  * Returns zero on success; non-zero otherwise
771  */
772 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
773 {
774         int rc = 0;
775         struct inode *inode = dentry->d_inode;
776         struct dentry *lower_dentry;
777         struct file fake_ecryptfs_file;
778         struct ecryptfs_crypt_stat *crypt_stat;
779         loff_t i_size = i_size_read(inode);
780         loff_t lower_size_before_truncate;
781         loff_t lower_size_after_truncate;
782
783         if (unlikely((new_length == i_size)))
784                 goto out;
785         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
786         /* Set up a fake ecryptfs file, this is used to interface with
787          * the file in the underlying filesystem so that the
788          * truncation has an effect there as well. */
789         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
790         fake_ecryptfs_file.f_path.dentry = dentry;
791         /* Released at out_free: label */
792         ecryptfs_set_file_private(&fake_ecryptfs_file,
793                                   kmem_cache_alloc(ecryptfs_file_info_cache,
794                                                    GFP_KERNEL));
795         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
796                 rc = -ENOMEM;
797                 goto out;
798         }
799         lower_dentry = ecryptfs_dentry_to_lower(dentry);
800         ecryptfs_set_file_lower(
801                 &fake_ecryptfs_file,
802                 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
803         /* Switch on growing or shrinking file */
804         if (new_length > i_size) {
805                 char zero[] = { 0x00 };
806
807                 /* Write a single 0 at the last position of the file;
808                  * this triggers code that will fill in 0's throughout
809                  * the intermediate portion of the previous end of the
810                  * file and the new and of the file */
811                 rc = ecryptfs_write(&fake_ecryptfs_file, zero,
812                                     (new_length - 1), 1);
813         } else { /* new_length < i_size_read(inode) */
814                 /* We're chopping off all the pages down do the page
815                  * in which new_length is located. Fill in the end of
816                  * that page from (new_length & ~PAGE_CACHE_MASK) to
817                  * PAGE_CACHE_SIZE with zeros. */
818                 size_t num_zeros = (PAGE_CACHE_SIZE
819                                     - (new_length & ~PAGE_CACHE_MASK));
820
821                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
822                         rc = vmtruncate(inode, new_length);
823                         if (rc)
824                                 goto out_free;
825                         rc = vmtruncate(lower_dentry->d_inode, new_length);
826                         goto out_free;
827                 }
828                 if (num_zeros) {
829                         char *zeros_virt;
830
831                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
832                         if (!zeros_virt) {
833                                 rc = -ENOMEM;
834                                 goto out_free;
835                         }
836                         rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
837                                             new_length, num_zeros);
838                         kfree(zeros_virt);
839                         if (rc) {
840                                 printk(KERN_ERR "Error attempting to zero out "
841                                        "the remainder of the end page on "
842                                        "reducing truncate; rc = [%d]\n", rc);
843                                 goto out_free;
844                         }
845                 }
846                 vmtruncate(inode, new_length);
847                 rc = ecryptfs_write_inode_size_to_metadata(inode);
848                 if (rc) {
849                         printk(KERN_ERR "Problem with "
850                                "ecryptfs_write_inode_size_to_metadata; "
851                                "rc = [%d]\n", rc);
852                         goto out_free;
853                 }
854                 /* We are reducing the size of the ecryptfs file, and need to
855                  * know if we need to reduce the size of the lower file. */
856                 lower_size_before_truncate =
857                     upper_size_to_lower_size(crypt_stat, i_size);
858                 lower_size_after_truncate =
859                     upper_size_to_lower_size(crypt_stat, new_length);
860                 if (lower_size_after_truncate < lower_size_before_truncate)
861                         vmtruncate(lower_dentry->d_inode,
862                                    lower_size_after_truncate);
863         }
864 out_free:
865         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
866                 kmem_cache_free(ecryptfs_file_info_cache,
867                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
868 out:
869         return rc;
870 }
871
872 static int
873 ecryptfs_permission(struct inode *inode, int mask)
874 {
875         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
876 }
877
878 /**
879  * ecryptfs_setattr
880  * @dentry: dentry handle to the inode to modify
881  * @ia: Structure with flags of what to change and values
882  *
883  * Updates the metadata of an inode. If the update is to the size
884  * i.e. truncation, then ecryptfs_truncate will handle the size modification
885  * of both the ecryptfs inode and the lower inode.
886  *
887  * All other metadata changes will be passed right to the lower filesystem,
888  * and we will just update our inode to look like the lower.
889  */
890 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
891 {
892         int rc = 0;
893         struct dentry *lower_dentry;
894         struct inode *inode;
895         struct inode *lower_inode;
896         struct ecryptfs_crypt_stat *crypt_stat;
897
898         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
899         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
900                 ecryptfs_init_crypt_stat(crypt_stat);
901         inode = dentry->d_inode;
902         lower_inode = ecryptfs_inode_to_lower(inode);
903         lower_dentry = ecryptfs_dentry_to_lower(dentry);
904         mutex_lock(&crypt_stat->cs_mutex);
905         if (S_ISDIR(dentry->d_inode->i_mode))
906                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
907         else if (S_ISREG(dentry->d_inode->i_mode)
908                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
909                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
910                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
911
912                 mount_crypt_stat = &ecryptfs_superblock_to_private(
913                         dentry->d_sb)->mount_crypt_stat;
914                 rc = ecryptfs_read_metadata(dentry);
915                 if (rc) {
916                         if (!(mount_crypt_stat->flags
917                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
918                                 rc = -EIO;
919                                 printk(KERN_WARNING "Either the lower file "
920                                        "is not in a valid eCryptfs format, "
921                                        "or the key could not be retrieved. "
922                                        "Plaintext passthrough mode is not "
923                                        "enabled; returning -EIO\n");
924                                 mutex_unlock(&crypt_stat->cs_mutex);
925                                 goto out;
926                         }
927                         rc = 0;
928                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
929                 }
930         }
931         mutex_unlock(&crypt_stat->cs_mutex);
932         if (ia->ia_valid & ATTR_SIZE) {
933                 ecryptfs_printk(KERN_DEBUG,
934                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
935                                 ia->ia_valid, ATTR_SIZE);
936                 rc = ecryptfs_truncate(dentry, ia->ia_size);
937                 /* ecryptfs_truncate handles resizing of the lower file */
938                 ia->ia_valid &= ~ATTR_SIZE;
939                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
940                                 ia->ia_valid);
941                 if (rc < 0)
942                         goto out;
943         }
944
945         /*
946          * mode change is for clearing setuid/setgid bits. Allow lower fs
947          * to interpret this in its own way.
948          */
949         if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
950                 ia->ia_valid &= ~ATTR_MODE;
951
952         mutex_lock(&lower_dentry->d_inode->i_mutex);
953         rc = notify_change(lower_dentry, ia);
954         mutex_unlock(&lower_dentry->d_inode->i_mutex);
955 out:
956         fsstack_copy_attr_all(inode, lower_inode, NULL);
957         return rc;
958 }
959
960 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
961                           struct kstat *stat)
962 {
963         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
964         int rc = 0;
965
966         mount_crypt_stat = &ecryptfs_superblock_to_private(
967                                                 dentry->d_sb)->mount_crypt_stat;
968         generic_fillattr(dentry->d_inode, stat);
969         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
970                 char *target;
971                 size_t targetsiz;
972
973                 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
974                 if (!rc) {
975                         kfree(target);
976                         stat->size = targetsiz;
977                 }
978         }
979         return rc;
980 }
981
982 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
983                      struct kstat *stat)
984 {
985         struct kstat lower_stat;
986         int rc;
987
988         rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
989                          ecryptfs_dentry_to_lower(dentry), &lower_stat);
990         if (!rc) {
991                 fsstack_copy_attr_all(dentry->d_inode,
992                                       ecryptfs_inode_to_lower(dentry->d_inode), NULL);
993                 generic_fillattr(dentry->d_inode, stat);
994                 stat->blocks = lower_stat.blocks;
995         }
996         return rc;
997 }
998
999 int
1000 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1001                   size_t size, int flags)
1002 {
1003         int rc = 0;
1004         struct dentry *lower_dentry;
1005
1006         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1007         if (!lower_dentry->d_inode->i_op->setxattr) {
1008                 rc = -EOPNOTSUPP;
1009                 goto out;
1010         }
1011         mutex_lock(&lower_dentry->d_inode->i_mutex);
1012         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
1013                                                    size, flags);
1014         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1015 out:
1016         return rc;
1017 }
1018
1019 ssize_t
1020 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1021                         void *value, size_t size)
1022 {
1023         int rc = 0;
1024
1025         if (!lower_dentry->d_inode->i_op->getxattr) {
1026                 rc = -EOPNOTSUPP;
1027                 goto out;
1028         }
1029         mutex_lock(&lower_dentry->d_inode->i_mutex);
1030         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1031                                                    size);
1032         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1033 out:
1034         return rc;
1035 }
1036
1037 static ssize_t
1038 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1039                   size_t size)
1040 {
1041         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1042                                        value, size);
1043 }
1044
1045 static ssize_t
1046 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1047 {
1048         int rc = 0;
1049         struct dentry *lower_dentry;
1050
1051         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1052         if (!lower_dentry->d_inode->i_op->listxattr) {
1053                 rc = -EOPNOTSUPP;
1054                 goto out;
1055         }
1056         mutex_lock(&lower_dentry->d_inode->i_mutex);
1057         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1058         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1059 out:
1060         return rc;
1061 }
1062
1063 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1064 {
1065         int rc = 0;
1066         struct dentry *lower_dentry;
1067
1068         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1069         if (!lower_dentry->d_inode->i_op->removexattr) {
1070                 rc = -EOPNOTSUPP;
1071                 goto out;
1072         }
1073         mutex_lock(&lower_dentry->d_inode->i_mutex);
1074         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1075         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1076 out:
1077         return rc;
1078 }
1079
1080 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1081 {
1082         if ((ecryptfs_inode_to_lower(inode)
1083              == (struct inode *)candidate_lower_inode))
1084                 return 1;
1085         else
1086                 return 0;
1087 }
1088
1089 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1090 {
1091         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1092         return 0;
1093 }
1094
1095 const struct inode_operations ecryptfs_symlink_iops = {
1096         .readlink = ecryptfs_readlink,
1097         .follow_link = ecryptfs_follow_link,
1098         .put_link = ecryptfs_put_link,
1099         .permission = ecryptfs_permission,
1100         .setattr = ecryptfs_setattr,
1101         .getattr = ecryptfs_getattr_link,
1102         .setxattr = ecryptfs_setxattr,
1103         .getxattr = ecryptfs_getxattr,
1104         .listxattr = ecryptfs_listxattr,
1105         .removexattr = ecryptfs_removexattr
1106 };
1107
1108 const struct inode_operations ecryptfs_dir_iops = {
1109         .create = ecryptfs_create,
1110         .lookup = ecryptfs_lookup,
1111         .link = ecryptfs_link,
1112         .unlink = ecryptfs_unlink,
1113         .symlink = ecryptfs_symlink,
1114         .mkdir = ecryptfs_mkdir,
1115         .rmdir = ecryptfs_rmdir,
1116         .mknod = ecryptfs_mknod,
1117         .rename = ecryptfs_rename,
1118         .permission = ecryptfs_permission,
1119         .setattr = ecryptfs_setattr,
1120         .setxattr = ecryptfs_setxattr,
1121         .getxattr = ecryptfs_getxattr,
1122         .listxattr = ecryptfs_listxattr,
1123         .removexattr = ecryptfs_removexattr
1124 };
1125
1126 const struct inode_operations ecryptfs_main_iops = {
1127         .permission = ecryptfs_permission,
1128         .setattr = ecryptfs_setattr,
1129         .getattr = ecryptfs_getattr,
1130         .setxattr = ecryptfs_setxattr,
1131         .getxattr = ecryptfs_getxattr,
1132         .listxattr = ecryptfs_listxattr,
1133         .removexattr = ecryptfs_removexattr
1134 };