Merge master.kernel.org:/pub/scm/linux/kernel/git/willy/parisc-2.6
[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) 2004-2006 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 "ecryptfs_kernel.h"
34
35 static struct dentry *lock_parent(struct dentry *dentry)
36 {
37         struct dentry *dir;
38
39         dir = dget(dentry->d_parent);
40         mutex_lock(&(dir->d_inode->i_mutex));
41         return dir;
42 }
43
44 static void unlock_parent(struct dentry *dentry)
45 {
46         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
47         dput(dentry->d_parent);
48 }
49
50 static void unlock_dir(struct dentry *dir)
51 {
52         mutex_unlock(&dir->d_inode->i_mutex);
53         dput(dir);
54 }
55
56 void ecryptfs_copy_inode_size(struct inode *dst, const struct inode *src)
57 {
58         i_size_write(dst, i_size_read((struct inode *)src));
59         dst->i_blocks = src->i_blocks;
60 }
61
62 void ecryptfs_copy_attr_atime(struct inode *dest, const struct inode *src)
63 {
64         dest->i_atime = src->i_atime;
65 }
66
67 static void ecryptfs_copy_attr_times(struct inode *dest,
68                                      const struct inode *src)
69 {
70         dest->i_atime = src->i_atime;
71         dest->i_mtime = src->i_mtime;
72         dest->i_ctime = src->i_ctime;
73 }
74
75 static void ecryptfs_copy_attr_timesizes(struct inode *dest,
76                                          const struct inode *src)
77 {
78         dest->i_atime = src->i_atime;
79         dest->i_mtime = src->i_mtime;
80         dest->i_ctime = src->i_ctime;
81         ecryptfs_copy_inode_size(dest, src);
82 }
83
84 void ecryptfs_copy_attr_all(struct inode *dest, const struct inode *src)
85 {
86         dest->i_mode = src->i_mode;
87         dest->i_nlink = src->i_nlink;
88         dest->i_uid = src->i_uid;
89         dest->i_gid = src->i_gid;
90         dest->i_rdev = src->i_rdev;
91         dest->i_atime = src->i_atime;
92         dest->i_mtime = src->i_mtime;
93         dest->i_ctime = src->i_ctime;
94         dest->i_blkbits = src->i_blkbits;
95         dest->i_flags = src->i_flags;
96 }
97
98 /**
99  * ecryptfs_create_underlying_file
100  * @lower_dir_inode: inode of the parent in the lower fs of the new file
101  * @lower_dentry: New file's dentry in the lower fs
102  * @ecryptfs_dentry: New file's dentry in ecryptfs
103  * @mode: The mode of the new file
104  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
105  *
106  * Creates the file in the lower file system.
107  *
108  * Returns zero on success; non-zero on error condition
109  */
110 static int
111 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
112                                 struct dentry *dentry, int mode,
113                                 struct nameidata *nd)
114 {
115         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
116         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
117         struct dentry *dentry_save;
118         struct vfsmount *vfsmount_save;
119         int rc;
120
121         dentry_save = nd->dentry;
122         vfsmount_save = nd->mnt;
123         nd->dentry = lower_dentry;
124         nd->mnt = lower_mnt;
125         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
126         nd->dentry = dentry_save;
127         nd->mnt = vfsmount_save;
128         return rc;
129 }
130
131 /**
132  * ecryptfs_do_create
133  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
134  * @ecryptfs_dentry: New file's dentry in ecryptfs
135  * @mode: The mode of the new file
136  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
137  *
138  * Creates the underlying file and the eCryptfs inode which will link to
139  * it. It will also update the eCryptfs directory inode to mimic the
140  * stat of the lower directory inode.
141  *
142  * Returns zero on success; non-zero on error condition
143  */
144 static int
145 ecryptfs_do_create(struct inode *directory_inode,
146                    struct dentry *ecryptfs_dentry, int mode,
147                    struct nameidata *nd)
148 {
149         int rc;
150         struct dentry *lower_dentry;
151         struct dentry *lower_dir_dentry;
152
153         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
154         lower_dir_dentry = lock_parent(lower_dentry);
155         if (unlikely(IS_ERR(lower_dir_dentry))) {
156                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
157                                 "dentry\n");
158                 rc = PTR_ERR(lower_dir_dentry);
159                 goto out;
160         }
161         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
162                                              ecryptfs_dentry, mode, nd);
163         if (unlikely(rc)) {
164                 ecryptfs_printk(KERN_ERR,
165                                 "Failure to create underlying file\n");
166                 goto out_lock;
167         }
168         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
169                                 directory_inode->i_sb, 0);
170         if (rc) {
171                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
172                 goto out_lock;
173         }
174         ecryptfs_copy_attr_timesizes(directory_inode,
175                                      lower_dir_dentry->d_inode);
176 out_lock:
177         unlock_dir(lower_dir_dentry);
178 out:
179         return rc;
180 }
181
182 /**
183  * grow_file
184  * @ecryptfs_dentry: the ecryptfs dentry
185  * @lower_file: The lower file
186  * @inode: The ecryptfs inode
187  * @lower_inode: The lower inode
188  *
189  * This is the code which will grow the file to its correct size.
190  */
191 static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
192                      struct inode *inode, struct inode *lower_inode)
193 {
194         int rc = 0;
195         struct file fake_file;
196         struct ecryptfs_file_info tmp_file_info;
197
198         memset(&fake_file, 0, sizeof(fake_file));
199         fake_file.f_dentry = ecryptfs_dentry;
200         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
201         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
202         ecryptfs_set_file_lower(&fake_file, lower_file);
203         rc = ecryptfs_fill_zeros(&fake_file, 1);
204         if (rc) {
205                 ECRYPTFS_SET_FLAG(
206                         ecryptfs_inode_to_private(inode)->crypt_stat.flags,
207                         ECRYPTFS_SECURITY_WARNING);
208                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
209                                 "in file; rc = [%d]\n", rc);
210                 goto out;
211         }
212         i_size_write(inode, 0);
213         ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
214         ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
215                           ECRYPTFS_NEW_FILE);
216 out:
217         return rc;
218 }
219
220 /**
221  * ecryptfs_initialize_file
222  *
223  * Cause the file to be changed from a basic empty file to an ecryptfs
224  * file with a header and first data page.
225  *
226  * Returns zero on success
227  */
228 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
229 {
230         int rc = 0;
231         int lower_flags;
232         struct ecryptfs_crypt_stat *crypt_stat;
233         struct dentry *lower_dentry;
234         struct dentry *tlower_dentry = NULL;
235         struct file *lower_file;
236         struct inode *inode, *lower_inode;
237         struct vfsmount *lower_mnt;
238
239         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
240         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
241                         lower_dentry->d_name.name);
242         inode = ecryptfs_dentry->d_inode;
243         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
244         tlower_dentry = dget(lower_dentry);
245         if (!tlower_dentry) {
246                 rc = -ENOMEM;
247                 ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry\n");
248                 goto out;
249         }
250         lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
251 #if BITS_PER_LONG != 32
252         lower_flags |= O_LARGEFILE;
253 #endif
254         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
255         mntget(lower_mnt);
256         /* Corresponding fput() at end of this function */
257         lower_file = dentry_open(tlower_dentry, lower_mnt, lower_flags);
258         if (IS_ERR(lower_file)) {
259                 rc = PTR_ERR(lower_file);
260                 ecryptfs_printk(KERN_ERR,
261                                 "Error opening dentry; rc = [%i]\n", rc);
262                 goto out;
263         }
264         /* fput(lower_file) should handle the puts if we do this */
265         lower_file->f_dentry = tlower_dentry;
266         lower_file->f_vfsmnt = lower_mnt;
267         lower_inode = tlower_dentry->d_inode;
268         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
269                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
270                 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
271                 goto out_fput;
272         }
273         ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
274         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
275         rc = ecryptfs_new_file_context(ecryptfs_dentry);
276         if (rc) {
277                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
278                                 "context\n");
279                 goto out_fput;
280         }
281         rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
282         if (rc) {
283                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
284                 goto out_fput;
285         }
286         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
287 out_fput:
288         fput(lower_file);
289 out:
290         return rc;
291 }
292
293 /**
294  * ecryptfs_create
295  * @dir: The inode of the directory in which to create the file.
296  * @dentry: The eCryptfs dentry
297  * @mode: The mode of the new file.
298  * @nd: nameidata
299  *
300  * Creates a new file.
301  *
302  * Returns zero on success; non-zero on error condition
303  */
304 static int
305 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
306                 int mode, struct nameidata *nd)
307 {
308         int rc;
309
310         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
311         if (unlikely(rc)) {
312                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
313                                 "lower filesystem\n");
314                 goto out;
315         }
316         /* At this point, a file exists on "disk"; we need to make sure
317          * that this on disk file is prepared to be an ecryptfs file */
318         rc = ecryptfs_initialize_file(ecryptfs_dentry);
319 out:
320         return rc;
321 }
322
323 /**
324  * ecryptfs_lookup
325  * @dir: inode
326  * @dentry: The dentry
327  * @nd: nameidata, may be NULL
328  *
329  * Find a file on disk. If the file does not exist, then we'll add it to the
330  * dentry cache and continue on to read it from the disk.
331  */
332 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
333                                       struct nameidata *nd)
334 {
335         int rc = 0;
336         struct dentry *lower_dir_dentry;
337         struct dentry *lower_dentry;
338         struct vfsmount *lower_mnt;
339         struct dentry *tlower_dentry = NULL;
340         char *encoded_name;
341         unsigned int encoded_namelen;
342         struct ecryptfs_crypt_stat *crypt_stat = NULL;
343         char *page_virt = NULL;
344         struct inode *lower_inode;
345         u64 file_size;
346
347         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
348         dentry->d_op = &ecryptfs_dops;
349         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
350             || (dentry->d_name.len == 2 && !strcmp(dentry->d_name.name, "..")))
351                 goto out_drop;
352         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
353                                                    dentry->d_name.name,
354                                                    dentry->d_name.len,
355                                                    &encoded_name);
356         if (encoded_namelen < 0) {
357                 rc = encoded_namelen;
358                 goto out_drop;
359         }
360         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
361                         "= [%d]\n", encoded_name, encoded_namelen);
362         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
363                                       encoded_namelen - 1);
364         kfree(encoded_name);
365         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
366         if (IS_ERR(lower_dentry)) {
367                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
368                 rc = PTR_ERR(lower_dentry);
369                 goto out_drop;
370         }
371         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
372                 "d_name.name = [%s]\n", lower_dentry,
373                 lower_dentry->d_name.name);
374         lower_inode = lower_dentry->d_inode;
375         ecryptfs_copy_attr_atime(dir, lower_dir_dentry->d_inode);
376         BUG_ON(!atomic_read(&lower_dentry->d_count));
377         ecryptfs_set_dentry_private(dentry,
378                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
379                                                      SLAB_KERNEL));
380         if (!ecryptfs_dentry_to_private(dentry)) {
381                 rc = -ENOMEM;
382                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
383                                 "to allocate ecryptfs_dentry_info struct\n");
384                 goto out_dput;
385         }
386         ecryptfs_set_dentry_lower(dentry, lower_dentry);
387         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
388         if (!lower_dentry->d_inode) {
389                 /* We want to add because we couldn't find in lower */
390                 d_add(dentry, NULL);
391                 goto out;
392         }
393         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
394         if (rc) {
395                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
396                 goto out_dput;
397         }
398         if (S_ISDIR(lower_inode->i_mode)) {
399                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
400                 goto out;
401         }
402         if (S_ISLNK(lower_inode->i_mode)) {
403                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
404                 goto out;
405         }
406         if (!nd) {
407                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
408                                 "as we *think* we are about to unlink\n");
409                 goto out;
410         }
411         tlower_dentry = dget(lower_dentry);
412         if (!tlower_dentry || IS_ERR(tlower_dentry)) {
413                 rc = -ENOMEM;
414                 ecryptfs_printk(KERN_ERR, "Cannot dget lower_dentry\n");
415                 goto out_dput;
416         }
417         /* Released in this function */
418         page_virt =
419             (char *)kmem_cache_alloc(ecryptfs_header_cache_2,
420                                      SLAB_USER);
421         if (!page_virt) {
422                 rc = -ENOMEM;
423                 ecryptfs_printk(KERN_ERR,
424                                 "Cannot ecryptfs_kmalloc a page\n");
425                 goto out_dput;
426         }
427         memset(page_virt, 0, PAGE_CACHE_SIZE);
428         rc = ecryptfs_read_header_region(page_virt, tlower_dentry, nd->mnt);
429         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
430         if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
431                 ecryptfs_set_default_sizes(crypt_stat);
432         if (rc) {
433                 rc = 0;
434                 ecryptfs_printk(KERN_WARNING, "Error reading header region;"
435                                 " assuming unencrypted\n");
436         } else {
437                 if (!contains_ecryptfs_marker(page_virt
438                                               + ECRYPTFS_FILE_SIZE_BYTES)) {
439                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
440                         goto out;
441                 }
442                 memcpy(&file_size, page_virt, sizeof(file_size));
443                 file_size = be64_to_cpu(file_size);
444                 i_size_write(dentry->d_inode, (loff_t)file_size);
445         }
446         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
447         goto out;
448
449 out_dput:
450         dput(lower_dentry);
451         if (tlower_dentry)
452                 dput(tlower_dentry);
453 out_drop:
454         d_drop(dentry);
455 out:
456         return ERR_PTR(rc);
457 }
458
459 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
460                          struct dentry *new_dentry)
461 {
462         struct dentry *lower_old_dentry;
463         struct dentry *lower_new_dentry;
464         struct dentry *lower_dir_dentry;
465         u64 file_size_save;
466         int rc;
467
468         file_size_save = i_size_read(old_dentry->d_inode);
469         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
470         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
471         dget(lower_old_dentry);
472         dget(lower_new_dentry);
473         lower_dir_dentry = lock_parent(lower_new_dentry);
474         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
475                       lower_new_dentry);
476         if (rc || !lower_new_dentry->d_inode)
477                 goto out_lock;
478         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
479         if (rc)
480                 goto out_lock;
481         ecryptfs_copy_attr_timesizes(dir, lower_new_dentry->d_inode);
482         old_dentry->d_inode->i_nlink =
483                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
484         i_size_write(new_dentry->d_inode, file_size_save);
485 out_lock:
486         unlock_dir(lower_dir_dentry);
487         dput(lower_new_dentry);
488         dput(lower_old_dentry);
489         if (!new_dentry->d_inode)
490                 d_drop(new_dentry);
491         return rc;
492 }
493
494 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
495 {
496         int rc = 0;
497         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
498         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
499
500         lock_parent(lower_dentry);
501         rc = vfs_unlink(lower_dir_inode, lower_dentry);
502         if (rc) {
503                 ecryptfs_printk(KERN_ERR, "Error in vfs_unlink\n");
504                 goto out_unlock;
505         }
506         ecryptfs_copy_attr_times(dir, lower_dir_inode);
507         dentry->d_inode->i_nlink =
508                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
509         dentry->d_inode->i_ctime = dir->i_ctime;
510 out_unlock:
511         unlock_parent(lower_dentry);
512         return rc;
513 }
514
515 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
516                             const char *symname)
517 {
518         int rc;
519         struct dentry *lower_dentry;
520         struct dentry *lower_dir_dentry;
521         umode_t mode;
522         char *encoded_symname;
523         unsigned int encoded_symlen;
524         struct ecryptfs_crypt_stat *crypt_stat = NULL;
525
526         lower_dentry = ecryptfs_dentry_to_lower(dentry);
527         dget(lower_dentry);
528         lower_dir_dentry = lock_parent(lower_dentry);
529         mode = S_IALLUGO;
530         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
531                                                   strlen(symname),
532                                                   &encoded_symname);
533         if (encoded_symlen < 0) {
534                 rc = encoded_symlen;
535                 goto out_lock;
536         }
537         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
538                          encoded_symname, mode);
539         kfree(encoded_symname);
540         if (rc || !lower_dentry->d_inode)
541                 goto out_lock;
542         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
543         if (rc)
544                 goto out_lock;
545         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
546 out_lock:
547         unlock_dir(lower_dir_dentry);
548         dput(lower_dentry);
549         if (!dentry->d_inode)
550                 d_drop(dentry);
551         return rc;
552 }
553
554 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
555 {
556         int rc;
557         struct dentry *lower_dentry;
558         struct dentry *lower_dir_dentry;
559
560         lower_dentry = ecryptfs_dentry_to_lower(dentry);
561         lower_dir_dentry = lock_parent(lower_dentry);
562         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
563         if (rc || !lower_dentry->d_inode)
564                 goto out;
565         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
566         if (rc)
567                 goto out;
568         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
569         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
570 out:
571         unlock_dir(lower_dir_dentry);
572         if (!dentry->d_inode)
573                 d_drop(dentry);
574         return rc;
575 }
576
577 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
578 {
579         int rc = 0;
580         struct dentry *tdentry = NULL;
581         struct dentry *lower_dentry;
582         struct dentry *tlower_dentry = NULL;
583         struct dentry *lower_dir_dentry;
584
585         lower_dentry = ecryptfs_dentry_to_lower(dentry);
586         if (!(tdentry = dget(dentry))) {
587                 rc = -EINVAL;
588                 ecryptfs_printk(KERN_ERR, "Error dget'ing dentry [%p]\n",
589                                 dentry);
590                 goto out;
591         }
592         lower_dir_dentry = lock_parent(lower_dentry);
593         if (!(tlower_dentry = dget(lower_dentry))) {
594                 rc = -EINVAL;
595                 ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry "
596                                 "[%p]\n", lower_dentry);
597                 goto out;
598         }
599         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
600         if (!rc) {
601                 d_delete(tlower_dentry);
602                 tlower_dentry = NULL;
603         }
604         ecryptfs_copy_attr_times(dir, lower_dir_dentry->d_inode);
605         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
606         unlock_dir(lower_dir_dentry);
607         if (!rc)
608                 d_drop(dentry);
609 out:
610         if (tdentry)
611                 dput(tdentry);
612         if (tlower_dentry)
613                 dput(tlower_dentry);
614         return rc;
615 }
616
617 static int
618 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
619 {
620         int rc;
621         struct dentry *lower_dentry;
622         struct dentry *lower_dir_dentry;
623
624         lower_dentry = ecryptfs_dentry_to_lower(dentry);
625         lower_dir_dentry = lock_parent(lower_dentry);
626         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
627         if (rc || !lower_dentry->d_inode)
628                 goto out;
629         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
630         if (rc)
631                 goto out;
632         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
633 out:
634         unlock_dir(lower_dir_dentry);
635         if (!dentry->d_inode)
636                 d_drop(dentry);
637         return rc;
638 }
639
640 static int
641 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
642                 struct inode *new_dir, struct dentry *new_dentry)
643 {
644         int rc;
645         struct dentry *lower_old_dentry;
646         struct dentry *lower_new_dentry;
647         struct dentry *lower_old_dir_dentry;
648         struct dentry *lower_new_dir_dentry;
649
650         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
651         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
652         dget(lower_old_dentry);
653         dget(lower_new_dentry);
654         lower_old_dir_dentry = dget_parent(lower_old_dentry);
655         lower_new_dir_dentry = dget_parent(lower_new_dentry);
656         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
657         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
658                         lower_new_dir_dentry->d_inode, lower_new_dentry);
659         if (rc)
660                 goto out_lock;
661         ecryptfs_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
662         if (new_dir != old_dir)
663                 ecryptfs_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
664 out_lock:
665         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
666         dput(lower_new_dentry);
667         dput(lower_old_dentry);
668         return rc;
669 }
670
671 static int
672 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
673 {
674         int rc;
675         struct dentry *lower_dentry;
676         char *decoded_name;
677         char *lower_buf;
678         mm_segment_t old_fs;
679         struct ecryptfs_crypt_stat *crypt_stat;
680
681         lower_dentry = ecryptfs_dentry_to_lower(dentry);
682         if (!lower_dentry->d_inode->i_op ||
683             !lower_dentry->d_inode->i_op->readlink) {
684                 rc = -EINVAL;
685                 goto out;
686         }
687         /* Released in this function */
688         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
689         if (lower_buf == NULL) {
690                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
691                 rc = -ENOMEM;
692                 goto out;
693         }
694         old_fs = get_fs();
695         set_fs(get_ds());
696         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
697                         "lower_dentry->d_name.name = [%s]\n",
698                         lower_dentry->d_name.name);
699         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
700                                                    (char __user *)lower_buf,
701                                                    bufsiz);
702         set_fs(old_fs);
703         if (rc >= 0) {
704                 crypt_stat = NULL;
705                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
706                                               &decoded_name);
707                 if (rc == -ENOMEM)
708                         goto out_free_lower_buf;
709                 if (rc > 0) {
710                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
711                                         "to userspace: [%*s]\n", rc,
712                                         decoded_name);
713                         if (copy_to_user(buf, decoded_name, rc))
714                                 rc = -EFAULT;
715                 }
716                 kfree(decoded_name);
717                 ecryptfs_copy_attr_atime(dentry->d_inode,
718                                          lower_dentry->d_inode);
719         }
720 out_free_lower_buf:
721         kfree(lower_buf);
722 out:
723         return rc;
724 }
725
726 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
727 {
728         char *buf;
729         int len = PAGE_SIZE, rc;
730         mm_segment_t old_fs;
731
732         /* Released in ecryptfs_put_link(); only release here on error */
733         buf = kmalloc(len, GFP_KERNEL);
734         if (!buf) {
735                 rc = -ENOMEM;
736                 goto out;
737         }
738         old_fs = get_fs();
739         set_fs(get_ds());
740         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
741                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
742         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
743         buf[rc] = '\0';
744         set_fs(old_fs);
745         if (rc < 0)
746                 goto out_free;
747         rc = 0;
748         nd_set_link(nd, buf);
749         goto out;
750 out_free:
751         kfree(buf);
752 out:
753         return ERR_PTR(rc);
754 }
755
756 static void
757 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
758 {
759         /* Free the char* */
760         kfree(nd_get_link(nd));
761 }
762
763 /**
764  * upper_size_to_lower_size
765  * @crypt_stat: Crypt_stat associated with file
766  * @upper_size: Size of the upper file
767  *
768  * Calculate the requried size of the lower file based on the
769  * specified size of the upper file. This calculation is based on the
770  * number of headers in the underlying file and the extent size.
771  *
772  * Returns Calculated size of the lower file.
773  */
774 static loff_t
775 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
776                          loff_t upper_size)
777 {
778         loff_t lower_size;
779
780         lower_size = ( crypt_stat->header_extent_size
781                        * crypt_stat->num_header_extents_at_front );
782         if (upper_size != 0) {
783                 loff_t num_extents;
784
785                 num_extents = upper_size >> crypt_stat->extent_shift;
786                 if (upper_size & ~crypt_stat->extent_mask)
787                         num_extents++;
788                 lower_size += (num_extents * crypt_stat->extent_size);
789         }
790         return lower_size;
791 }
792
793 /**
794  * ecryptfs_truncate
795  * @dentry: The ecryptfs layer dentry
796  * @new_length: The length to expand the file to
797  *
798  * Function to handle truncations modifying the size of the file. Note
799  * that the file sizes are interpolated. When expanding, we are simply
800  * writing strings of 0's out. When truncating, we need to modify the
801  * underlying file size according to the page index interpolations.
802  *
803  * Returns zero on success; non-zero otherwise
804  */
805 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
806 {
807         int rc = 0;
808         struct inode *inode = dentry->d_inode;
809         struct dentry *lower_dentry;
810         struct vfsmount *lower_mnt;
811         struct file fake_ecryptfs_file, *lower_file = NULL;
812         struct ecryptfs_crypt_stat *crypt_stat;
813         loff_t i_size = i_size_read(inode);
814         loff_t lower_size_before_truncate;
815         loff_t lower_size_after_truncate;
816
817         if (unlikely((new_length == i_size)))
818                 goto out;
819         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
820         /* Set up a fake ecryptfs file, this is used to interface with
821          * the file in the underlying filesystem so that the
822          * truncation has an effect there as well. */
823         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
824         fake_ecryptfs_file.f_dentry = dentry;
825         /* Released at out_free: label */
826         ecryptfs_set_file_private(&fake_ecryptfs_file,
827                                   kmem_cache_alloc(ecryptfs_file_info_cache,
828                                                    SLAB_KERNEL));
829         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
830                 rc = -ENOMEM;
831                 goto out;
832         }
833         lower_dentry = ecryptfs_dentry_to_lower(dentry);
834         /* This dget & mntget is released through fput at out_fput: */
835         dget(lower_dentry);
836         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
837         mntget(lower_mnt);
838         lower_file = dentry_open(lower_dentry, lower_mnt, O_RDWR);
839         if (unlikely(IS_ERR(lower_file))) {
840                 rc = PTR_ERR(lower_file);
841                 goto out_free;
842         }
843         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
844         /* Switch on growing or shrinking file */
845         if (new_length > i_size) {
846                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
847                 if (rc) {
848                         ecryptfs_printk(KERN_ERR,
849                                         "Problem with fill_zeros\n");
850                         goto out_fput;
851                 }
852                 i_size_write(inode, new_length);
853                 rc = ecryptfs_write_inode_size_to_header(lower_file,
854                                                          lower_dentry->d_inode,
855                                                          inode);
856                 if (rc) {
857                         ecryptfs_printk(KERN_ERR,
858                                         "Problem with ecryptfs_write"
859                                         "_inode_size\n");
860                         goto out_fput;
861                 }
862         } else { /* new_length < i_size_read(inode) */
863                 vmtruncate(inode, new_length);
864                 ecryptfs_write_inode_size_to_header(lower_file,
865                                                     lower_dentry->d_inode,
866                                                     inode);
867                 /* We are reducing the size of the ecryptfs file, and need to
868                  * know if we need to reduce the size of the lower file. */
869                 lower_size_before_truncate =
870                     upper_size_to_lower_size(crypt_stat, i_size);
871                 lower_size_after_truncate =
872                     upper_size_to_lower_size(crypt_stat, new_length);
873                 if (lower_size_after_truncate < lower_size_before_truncate)
874                         vmtruncate(lower_dentry->d_inode,
875                                    lower_size_after_truncate);
876         }
877         /* Update the access times */
878         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
879                 = CURRENT_TIME;
880         mark_inode_dirty_sync(inode);
881 out_fput:
882         fput(lower_file);
883 out_free:
884         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
885                 kmem_cache_free(ecryptfs_file_info_cache,
886                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
887 out:
888         return rc;
889 }
890
891 static int
892 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
893 {
894         int rc;
895
896         if (nd) {
897                 struct vfsmount *vfsmnt_save = nd->mnt;
898                 struct dentry *dentry_save = nd->dentry;
899
900                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
901                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
902                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
903                 nd->mnt = vfsmnt_save;
904                 nd->dentry = dentry_save;
905         } else
906                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
907         return rc;
908 }
909
910 /**
911  * ecryptfs_setattr
912  * @dentry: dentry handle to the inode to modify
913  * @ia: Structure with flags of what to change and values
914  *
915  * Updates the metadata of an inode. If the update is to the size
916  * i.e. truncation, then ecryptfs_truncate will handle the size modification
917  * of both the ecryptfs inode and the lower inode.
918  *
919  * All other metadata changes will be passed right to the lower filesystem,
920  * and we will just update our inode to look like the lower.
921  */
922 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
923 {
924         int rc = 0;
925         struct dentry *lower_dentry;
926         struct inode *inode;
927         struct inode *lower_inode;
928         struct ecryptfs_crypt_stat *crypt_stat;
929
930         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
931         lower_dentry = ecryptfs_dentry_to_lower(dentry);
932         inode = dentry->d_inode;
933         lower_inode = ecryptfs_inode_to_lower(inode);
934         if (ia->ia_valid & ATTR_SIZE) {
935                 ecryptfs_printk(KERN_DEBUG,
936                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
937                                 ia->ia_valid, ATTR_SIZE);
938                 rc = ecryptfs_truncate(dentry, ia->ia_size);
939                 /* ecryptfs_truncate handles resizing of the lower file */
940                 ia->ia_valid &= ~ATTR_SIZE;
941                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
942                                 ia->ia_valid);
943                 if (rc < 0)
944                         goto out;
945         }
946         rc = notify_change(lower_dentry, ia);
947 out:
948         ecryptfs_copy_attr_all(inode, lower_inode);
949         return rc;
950 }
951
952 static int
953 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
954                   size_t size, int flags)
955 {
956         int rc = 0;
957         struct dentry *lower_dentry;
958
959         lower_dentry = ecryptfs_dentry_to_lower(dentry);
960         if (!lower_dentry->d_inode->i_op->setxattr) {
961                 rc = -ENOSYS;
962                 goto out;
963         }
964         mutex_lock(&lower_dentry->d_inode->i_mutex);
965         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
966                                                    size, flags);
967         mutex_unlock(&lower_dentry->d_inode->i_mutex);
968 out:
969         return rc;
970 }
971
972 static ssize_t
973 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
974                   size_t size)
975 {
976         int rc = 0;
977         struct dentry *lower_dentry;
978
979         lower_dentry = ecryptfs_dentry_to_lower(dentry);
980         if (!lower_dentry->d_inode->i_op->getxattr) {
981                 rc = -ENOSYS;
982                 goto out;
983         }
984         mutex_lock(&lower_dentry->d_inode->i_mutex);
985         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
986                                                    size);
987         mutex_unlock(&lower_dentry->d_inode->i_mutex);
988 out:
989         return rc;
990 }
991
992 static ssize_t
993 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
994 {
995         int rc = 0;
996         struct dentry *lower_dentry;
997
998         lower_dentry = ecryptfs_dentry_to_lower(dentry);
999         if (!lower_dentry->d_inode->i_op->listxattr) {
1000                 rc = -ENOSYS;
1001                 goto out;
1002         }
1003         mutex_lock(&lower_dentry->d_inode->i_mutex);
1004         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1005         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1006 out:
1007         return rc;
1008 }
1009
1010 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1011 {
1012         int rc = 0;
1013         struct dentry *lower_dentry;
1014
1015         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1016         if (!lower_dentry->d_inode->i_op->removexattr) {
1017                 rc = -ENOSYS;
1018                 goto out;
1019         }
1020         mutex_lock(&lower_dentry->d_inode->i_mutex);
1021         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1022         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1023 out:
1024         return rc;
1025 }
1026
1027 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1028 {
1029         if ((ecryptfs_inode_to_lower(inode)
1030              == (struct inode *)candidate_lower_inode))
1031                 return 1;
1032         else
1033                 return 0;
1034 }
1035
1036 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1037 {
1038         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1039         return 0;
1040 }
1041
1042 struct inode_operations ecryptfs_symlink_iops = {
1043         .readlink = ecryptfs_readlink,
1044         .follow_link = ecryptfs_follow_link,
1045         .put_link = ecryptfs_put_link,
1046         .permission = ecryptfs_permission,
1047         .setattr = ecryptfs_setattr,
1048         .setxattr = ecryptfs_setxattr,
1049         .getxattr = ecryptfs_getxattr,
1050         .listxattr = ecryptfs_listxattr,
1051         .removexattr = ecryptfs_removexattr
1052 };
1053
1054 struct inode_operations ecryptfs_dir_iops = {
1055         .create = ecryptfs_create,
1056         .lookup = ecryptfs_lookup,
1057         .link = ecryptfs_link,
1058         .unlink = ecryptfs_unlink,
1059         .symlink = ecryptfs_symlink,
1060         .mkdir = ecryptfs_mkdir,
1061         .rmdir = ecryptfs_rmdir,
1062         .mknod = ecryptfs_mknod,
1063         .rename = ecryptfs_rename,
1064         .permission = ecryptfs_permission,
1065         .setattr = ecryptfs_setattr,
1066         .setxattr = ecryptfs_setxattr,
1067         .getxattr = ecryptfs_getxattr,
1068         .listxattr = ecryptfs_listxattr,
1069         .removexattr = ecryptfs_removexattr
1070 };
1071
1072 struct inode_operations ecryptfs_main_iops = {
1073         .permission = ecryptfs_permission,
1074         .setattr = ecryptfs_setattr,
1075         .setxattr = ecryptfs_setxattr,
1076         .getxattr = ecryptfs_getxattr,
1077         .listxattr = ecryptfs_listxattr,
1078         .removexattr = ecryptfs_removexattr
1079 };