Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[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) 2004-2006 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 file *lower_file;
235         struct inode *inode, *lower_inode;
236         struct vfsmount *lower_mnt;
237
238         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
239         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
240                         lower_dentry->d_name.name);
241         inode = ecryptfs_dentry->d_inode;
242         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
243         lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
244 #if BITS_PER_LONG != 32
245         lower_flags |= O_LARGEFILE;
246 #endif
247         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
248         /* Corresponding fput() at end of this function */
249         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
250                                            lower_flags))) {
251                 ecryptfs_printk(KERN_ERR,
252                                 "Error opening dentry; rc = [%i]\n", rc);
253                 goto out;
254         }
255         lower_inode = lower_dentry->d_inode;
256         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
257                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
258                 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
259                 goto out_fput;
260         }
261         ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
262         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
263         rc = ecryptfs_new_file_context(ecryptfs_dentry);
264         if (rc) {
265                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
266                                 "context\n");
267                 goto out_fput;
268         }
269         rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
270         if (rc) {
271                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
272                 goto out_fput;
273         }
274         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
275 out_fput:
276         if ((rc = ecryptfs_close_lower_file(lower_file)))
277                 printk(KERN_ERR "Error closing lower_file\n");
278 out:
279         return rc;
280 }
281
282 /**
283  * ecryptfs_create
284  * @dir: The inode of the directory in which to create the file.
285  * @dentry: The eCryptfs dentry
286  * @mode: The mode of the new file.
287  * @nd: nameidata
288  *
289  * Creates a new file.
290  *
291  * Returns zero on success; non-zero on error condition
292  */
293 static int
294 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
295                 int mode, struct nameidata *nd)
296 {
297         int rc;
298
299         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
300         if (unlikely(rc)) {
301                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
302                                 "lower filesystem\n");
303                 goto out;
304         }
305         /* At this point, a file exists on "disk"; we need to make sure
306          * that this on disk file is prepared to be an ecryptfs file */
307         rc = ecryptfs_initialize_file(ecryptfs_dentry);
308 out:
309         return rc;
310 }
311
312 /**
313  * ecryptfs_lookup
314  * @dir: inode
315  * @dentry: The dentry
316  * @nd: nameidata, may be NULL
317  *
318  * Find a file on disk. If the file does not exist, then we'll add it to the
319  * dentry cache and continue on to read it from the disk.
320  */
321 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
322                                       struct nameidata *nd)
323 {
324         int rc = 0;
325         struct dentry *lower_dir_dentry;
326         struct dentry *lower_dentry;
327         struct vfsmount *lower_mnt;
328         char *encoded_name;
329         unsigned int encoded_namelen;
330         struct ecryptfs_crypt_stat *crypt_stat = NULL;
331         char *page_virt = NULL;
332         struct inode *lower_inode;
333         u64 file_size;
334
335         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
336         dentry->d_op = &ecryptfs_dops;
337         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
338             || (dentry->d_name.len == 2
339                 && !strcmp(dentry->d_name.name, ".."))) {
340                 d_drop(dentry);
341                 goto out;
342         }
343         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
344                                                    dentry->d_name.name,
345                                                    dentry->d_name.len,
346                                                    &encoded_name);
347         if (encoded_namelen < 0) {
348                 rc = encoded_namelen;
349                 d_drop(dentry);
350                 goto out;
351         }
352         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
353                         "= [%d]\n", encoded_name, encoded_namelen);
354         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
355                                       encoded_namelen - 1);
356         kfree(encoded_name);
357         if (IS_ERR(lower_dentry)) {
358                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
359                 rc = PTR_ERR(lower_dentry);
360                 d_drop(dentry);
361                 goto out;
362         }
363         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
364         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
365                 "d_name.name = [%s]\n", lower_dentry,
366                 lower_dentry->d_name.name);
367         lower_inode = lower_dentry->d_inode;
368         ecryptfs_copy_attr_atime(dir, lower_dir_dentry->d_inode);
369         BUG_ON(!atomic_read(&lower_dentry->d_count));
370         ecryptfs_set_dentry_private(dentry,
371                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
372                                                      SLAB_KERNEL));
373         if (!ecryptfs_dentry_to_private(dentry)) {
374                 rc = -ENOMEM;
375                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
376                                 "to allocate ecryptfs_dentry_info struct\n");
377                 goto out_dput;
378         }
379         ecryptfs_set_dentry_lower(dentry, lower_dentry);
380         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
381         if (!lower_dentry->d_inode) {
382                 /* We want to add because we couldn't find in lower */
383                 d_add(dentry, NULL);
384                 goto out;
385         }
386         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
387         if (rc) {
388                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
389                 goto out_dput;
390         }
391         if (S_ISDIR(lower_inode->i_mode)) {
392                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
393                 goto out;
394         }
395         if (S_ISLNK(lower_inode->i_mode)) {
396                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
397                 goto out;
398         }
399         if (!nd) {
400                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
401                                 "as we *think* we are about to unlink\n");
402                 goto out;
403         }
404         /* Released in this function */
405         page_virt =
406             (char *)kmem_cache_alloc(ecryptfs_header_cache_2,
407                                      SLAB_USER);
408         if (!page_virt) {
409                 rc = -ENOMEM;
410                 ecryptfs_printk(KERN_ERR,
411                                 "Cannot ecryptfs_kmalloc a page\n");
412                 goto out_dput;
413         }
414         memset(page_virt, 0, PAGE_CACHE_SIZE);
415         rc = ecryptfs_read_header_region(page_virt, lower_dentry, nd->mnt);
416         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
417         if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
418                 ecryptfs_set_default_sizes(crypt_stat);
419         if (rc) {
420                 rc = 0;
421                 ecryptfs_printk(KERN_WARNING, "Error reading header region;"
422                                 " assuming unencrypted\n");
423         } else {
424                 if (!contains_ecryptfs_marker(page_virt
425                                               + ECRYPTFS_FILE_SIZE_BYTES)) {
426                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
427                         goto out;
428                 }
429                 memcpy(&file_size, page_virt, sizeof(file_size));
430                 file_size = be64_to_cpu(file_size);
431                 i_size_write(dentry->d_inode, (loff_t)file_size);
432         }
433         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
434         goto out;
435
436 out_dput:
437         dput(lower_dentry);
438         d_drop(dentry);
439 out:
440         return ERR_PTR(rc);
441 }
442
443 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
444                          struct dentry *new_dentry)
445 {
446         struct dentry *lower_old_dentry;
447         struct dentry *lower_new_dentry;
448         struct dentry *lower_dir_dentry;
449         u64 file_size_save;
450         int rc;
451
452         file_size_save = i_size_read(old_dentry->d_inode);
453         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
454         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
455         dget(lower_old_dentry);
456         dget(lower_new_dentry);
457         lower_dir_dentry = lock_parent(lower_new_dentry);
458         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
459                       lower_new_dentry);
460         if (rc || !lower_new_dentry->d_inode)
461                 goto out_lock;
462         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
463         if (rc)
464                 goto out_lock;
465         ecryptfs_copy_attr_timesizes(dir, lower_new_dentry->d_inode);
466         old_dentry->d_inode->i_nlink =
467                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
468         i_size_write(new_dentry->d_inode, file_size_save);
469 out_lock:
470         unlock_dir(lower_dir_dentry);
471         dput(lower_new_dentry);
472         dput(lower_old_dentry);
473         d_drop(new_dentry);
474         d_drop(old_dentry);
475         return rc;
476 }
477
478 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
479 {
480         int rc = 0;
481         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
482         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
483
484         lock_parent(lower_dentry);
485         rc = vfs_unlink(lower_dir_inode, lower_dentry);
486         if (rc) {
487                 ecryptfs_printk(KERN_ERR, "Error in vfs_unlink\n");
488                 goto out_unlock;
489         }
490         ecryptfs_copy_attr_times(dir, lower_dir_inode);
491         dentry->d_inode->i_nlink =
492                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
493         dentry->d_inode->i_ctime = dir->i_ctime;
494 out_unlock:
495         unlock_parent(lower_dentry);
496         return rc;
497 }
498
499 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
500                             const char *symname)
501 {
502         int rc;
503         struct dentry *lower_dentry;
504         struct dentry *lower_dir_dentry;
505         umode_t mode;
506         char *encoded_symname;
507         unsigned int encoded_symlen;
508         struct ecryptfs_crypt_stat *crypt_stat = NULL;
509
510         lower_dentry = ecryptfs_dentry_to_lower(dentry);
511         dget(lower_dentry);
512         lower_dir_dentry = lock_parent(lower_dentry);
513         mode = S_IALLUGO;
514         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
515                                                   strlen(symname),
516                                                   &encoded_symname);
517         if (encoded_symlen < 0) {
518                 rc = encoded_symlen;
519                 goto out_lock;
520         }
521         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
522                          encoded_symname, mode);
523         kfree(encoded_symname);
524         if (rc || !lower_dentry->d_inode)
525                 goto out_lock;
526         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
527         if (rc)
528                 goto out_lock;
529         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
530 out_lock:
531         unlock_dir(lower_dir_dentry);
532         dput(lower_dentry);
533         if (!dentry->d_inode)
534                 d_drop(dentry);
535         return rc;
536 }
537
538 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
539 {
540         int rc;
541         struct dentry *lower_dentry;
542         struct dentry *lower_dir_dentry;
543
544         lower_dentry = ecryptfs_dentry_to_lower(dentry);
545         lower_dir_dentry = lock_parent(lower_dentry);
546         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
547         if (rc || !lower_dentry->d_inode)
548                 goto out;
549         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
550         if (rc)
551                 goto out;
552         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
553         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
554 out:
555         unlock_dir(lower_dir_dentry);
556         if (!dentry->d_inode)
557                 d_drop(dentry);
558         return rc;
559 }
560
561 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
562 {
563         struct dentry *lower_dentry;
564         struct dentry *lower_dir_dentry;
565         int rc;
566
567         lower_dentry = ecryptfs_dentry_to_lower(dentry);
568         dget(dentry);
569         lower_dir_dentry = lock_parent(lower_dentry);
570         dget(lower_dentry);
571         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
572         dput(lower_dentry);
573         if (!rc)
574                 d_delete(lower_dentry);
575         ecryptfs_copy_attr_times(dir, lower_dir_dentry->d_inode);
576         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
577         unlock_dir(lower_dir_dentry);
578         if (!rc)
579                 d_drop(dentry);
580         dput(dentry);
581         return rc;
582 }
583
584 static int
585 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
586 {
587         int rc;
588         struct dentry *lower_dentry;
589         struct dentry *lower_dir_dentry;
590
591         lower_dentry = ecryptfs_dentry_to_lower(dentry);
592         lower_dir_dentry = lock_parent(lower_dentry);
593         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
594         if (rc || !lower_dentry->d_inode)
595                 goto out;
596         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
597         if (rc)
598                 goto out;
599         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
600 out:
601         unlock_dir(lower_dir_dentry);
602         if (!dentry->d_inode)
603                 d_drop(dentry);
604         return rc;
605 }
606
607 static int
608 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
609                 struct inode *new_dir, struct dentry *new_dentry)
610 {
611         int rc;
612         struct dentry *lower_old_dentry;
613         struct dentry *lower_new_dentry;
614         struct dentry *lower_old_dir_dentry;
615         struct dentry *lower_new_dir_dentry;
616
617         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
618         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
619         dget(lower_old_dentry);
620         dget(lower_new_dentry);
621         lower_old_dir_dentry = dget_parent(lower_old_dentry);
622         lower_new_dir_dentry = dget_parent(lower_new_dentry);
623         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
624         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
625                         lower_new_dir_dentry->d_inode, lower_new_dentry);
626         if (rc)
627                 goto out_lock;
628         ecryptfs_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
629         if (new_dir != old_dir)
630                 ecryptfs_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
631 out_lock:
632         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
633         dput(lower_new_dentry);
634         dput(lower_old_dentry);
635         return rc;
636 }
637
638 static int
639 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
640 {
641         int rc;
642         struct dentry *lower_dentry;
643         char *decoded_name;
644         char *lower_buf;
645         mm_segment_t old_fs;
646         struct ecryptfs_crypt_stat *crypt_stat;
647
648         lower_dentry = ecryptfs_dentry_to_lower(dentry);
649         if (!lower_dentry->d_inode->i_op ||
650             !lower_dentry->d_inode->i_op->readlink) {
651                 rc = -EINVAL;
652                 goto out;
653         }
654         /* Released in this function */
655         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
656         if (lower_buf == NULL) {
657                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
658                 rc = -ENOMEM;
659                 goto out;
660         }
661         old_fs = get_fs();
662         set_fs(get_ds());
663         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
664                         "lower_dentry->d_name.name = [%s]\n",
665                         lower_dentry->d_name.name);
666         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
667                                                    (char __user *)lower_buf,
668                                                    bufsiz);
669         set_fs(old_fs);
670         if (rc >= 0) {
671                 crypt_stat = NULL;
672                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
673                                               &decoded_name);
674                 if (rc == -ENOMEM)
675                         goto out_free_lower_buf;
676                 if (rc > 0) {
677                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
678                                         "to userspace: [%*s]\n", rc,
679                                         decoded_name);
680                         if (copy_to_user(buf, decoded_name, rc))
681                                 rc = -EFAULT;
682                 }
683                 kfree(decoded_name);
684                 ecryptfs_copy_attr_atime(dentry->d_inode,
685                                          lower_dentry->d_inode);
686         }
687 out_free_lower_buf:
688         kfree(lower_buf);
689 out:
690         return rc;
691 }
692
693 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
694 {
695         char *buf;
696         int len = PAGE_SIZE, rc;
697         mm_segment_t old_fs;
698
699         /* Released in ecryptfs_put_link(); only release here on error */
700         buf = kmalloc(len, GFP_KERNEL);
701         if (!buf) {
702                 rc = -ENOMEM;
703                 goto out;
704         }
705         old_fs = get_fs();
706         set_fs(get_ds());
707         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
708                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
709         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
710         buf[rc] = '\0';
711         set_fs(old_fs);
712         if (rc < 0)
713                 goto out_free;
714         rc = 0;
715         nd_set_link(nd, buf);
716         goto out;
717 out_free:
718         kfree(buf);
719 out:
720         return ERR_PTR(rc);
721 }
722
723 static void
724 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
725 {
726         /* Free the char* */
727         kfree(nd_get_link(nd));
728 }
729
730 /**
731  * upper_size_to_lower_size
732  * @crypt_stat: Crypt_stat associated with file
733  * @upper_size: Size of the upper file
734  *
735  * Calculate the requried size of the lower file based on the
736  * specified size of the upper file. This calculation is based on the
737  * number of headers in the underlying file and the extent size.
738  *
739  * Returns Calculated size of the lower file.
740  */
741 static loff_t
742 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
743                          loff_t upper_size)
744 {
745         loff_t lower_size;
746
747         lower_size = ( crypt_stat->header_extent_size
748                        * crypt_stat->num_header_extents_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 vfsmount *lower_mnt;
778         struct file fake_ecryptfs_file, *lower_file = NULL;
779         struct ecryptfs_crypt_stat *crypt_stat;
780         loff_t i_size = i_size_read(inode);
781         loff_t lower_size_before_truncate;
782         loff_t lower_size_after_truncate;
783
784         if (unlikely((new_length == i_size)))
785                 goto out;
786         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
787         /* Set up a fake ecryptfs file, this is used to interface with
788          * the file in the underlying filesystem so that the
789          * truncation has an effect there as well. */
790         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
791         fake_ecryptfs_file.f_dentry = dentry;
792         /* Released at out_free: label */
793         ecryptfs_set_file_private(&fake_ecryptfs_file,
794                                   kmem_cache_alloc(ecryptfs_file_info_cache,
795                                                    SLAB_KERNEL));
796         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
797                 rc = -ENOMEM;
798                 goto out;
799         }
800         lower_dentry = ecryptfs_dentry_to_lower(dentry);
801         /* This dget & mntget is released through fput at out_fput: */
802         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
803         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
804                                            O_RDWR))) {
805                 ecryptfs_printk(KERN_ERR,
806                                 "Error opening dentry; rc = [%i]\n", rc);
807                 goto out_free;
808         }
809         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
810         /* Switch on growing or shrinking file */
811         if (new_length > i_size) {
812                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
813                 if (rc) {
814                         ecryptfs_printk(KERN_ERR,
815                                         "Problem with fill_zeros\n");
816                         goto out_fput;
817                 }
818                 i_size_write(inode, new_length);
819                 rc = ecryptfs_write_inode_size_to_header(lower_file,
820                                                          lower_dentry->d_inode,
821                                                          inode);
822                 if (rc) {
823                         ecryptfs_printk(KERN_ERR,
824                                         "Problem with ecryptfs_write"
825                                         "_inode_size\n");
826                         goto out_fput;
827                 }
828         } else { /* new_length < i_size_read(inode) */
829                 vmtruncate(inode, new_length);
830                 ecryptfs_write_inode_size_to_header(lower_file,
831                                                     lower_dentry->d_inode,
832                                                     inode);
833                 /* We are reducing the size of the ecryptfs file, and need to
834                  * know if we need to reduce the size of the lower file. */
835                 lower_size_before_truncate =
836                     upper_size_to_lower_size(crypt_stat, i_size);
837                 lower_size_after_truncate =
838                     upper_size_to_lower_size(crypt_stat, new_length);
839                 if (lower_size_after_truncate < lower_size_before_truncate)
840                         vmtruncate(lower_dentry->d_inode,
841                                    lower_size_after_truncate);
842         }
843         /* Update the access times */
844         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
845                 = CURRENT_TIME;
846         mark_inode_dirty_sync(inode);
847 out_fput:
848         if ((rc = ecryptfs_close_lower_file(lower_file)))
849                 printk(KERN_ERR "Error closing lower_file\n");
850 out_free:
851         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
852                 kmem_cache_free(ecryptfs_file_info_cache,
853                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
854 out:
855         return rc;
856 }
857
858 static int
859 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
860 {
861         int rc;
862
863         if (nd) {
864                 struct vfsmount *vfsmnt_save = nd->mnt;
865                 struct dentry *dentry_save = nd->dentry;
866
867                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
868                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
869                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
870                 nd->mnt = vfsmnt_save;
871                 nd->dentry = dentry_save;
872         } else
873                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
874         return rc;
875 }
876
877 /**
878  * ecryptfs_setattr
879  * @dentry: dentry handle to the inode to modify
880  * @ia: Structure with flags of what to change and values
881  *
882  * Updates the metadata of an inode. If the update is to the size
883  * i.e. truncation, then ecryptfs_truncate will handle the size modification
884  * of both the ecryptfs inode and the lower inode.
885  *
886  * All other metadata changes will be passed right to the lower filesystem,
887  * and we will just update our inode to look like the lower.
888  */
889 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
890 {
891         int rc = 0;
892         struct dentry *lower_dentry;
893         struct inode *inode;
894         struct inode *lower_inode;
895         struct ecryptfs_crypt_stat *crypt_stat;
896
897         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
898         lower_dentry = ecryptfs_dentry_to_lower(dentry);
899         inode = dentry->d_inode;
900         lower_inode = ecryptfs_inode_to_lower(inode);
901         if (ia->ia_valid & ATTR_SIZE) {
902                 ecryptfs_printk(KERN_DEBUG,
903                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
904                                 ia->ia_valid, ATTR_SIZE);
905                 rc = ecryptfs_truncate(dentry, ia->ia_size);
906                 /* ecryptfs_truncate handles resizing of the lower file */
907                 ia->ia_valid &= ~ATTR_SIZE;
908                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
909                                 ia->ia_valid);
910                 if (rc < 0)
911                         goto out;
912         }
913         rc = notify_change(lower_dentry, ia);
914 out:
915         ecryptfs_copy_attr_all(inode, lower_inode);
916         return rc;
917 }
918
919 static int
920 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
921                   size_t size, int flags)
922 {
923         int rc = 0;
924         struct dentry *lower_dentry;
925
926         lower_dentry = ecryptfs_dentry_to_lower(dentry);
927         if (!lower_dentry->d_inode->i_op->setxattr) {
928                 rc = -ENOSYS;
929                 goto out;
930         }
931         mutex_lock(&lower_dentry->d_inode->i_mutex);
932         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
933                                                    size, flags);
934         mutex_unlock(&lower_dentry->d_inode->i_mutex);
935 out:
936         return rc;
937 }
938
939 static ssize_t
940 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
941                   size_t size)
942 {
943         int rc = 0;
944         struct dentry *lower_dentry;
945
946         lower_dentry = ecryptfs_dentry_to_lower(dentry);
947         if (!lower_dentry->d_inode->i_op->getxattr) {
948                 rc = -ENOSYS;
949                 goto out;
950         }
951         mutex_lock(&lower_dentry->d_inode->i_mutex);
952         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
953                                                    size);
954         mutex_unlock(&lower_dentry->d_inode->i_mutex);
955 out:
956         return rc;
957 }
958
959 static ssize_t
960 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
961 {
962         int rc = 0;
963         struct dentry *lower_dentry;
964
965         lower_dentry = ecryptfs_dentry_to_lower(dentry);
966         if (!lower_dentry->d_inode->i_op->listxattr) {
967                 rc = -ENOSYS;
968                 goto out;
969         }
970         mutex_lock(&lower_dentry->d_inode->i_mutex);
971         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
972         mutex_unlock(&lower_dentry->d_inode->i_mutex);
973 out:
974         return rc;
975 }
976
977 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
978 {
979         int rc = 0;
980         struct dentry *lower_dentry;
981
982         lower_dentry = ecryptfs_dentry_to_lower(dentry);
983         if (!lower_dentry->d_inode->i_op->removexattr) {
984                 rc = -ENOSYS;
985                 goto out;
986         }
987         mutex_lock(&lower_dentry->d_inode->i_mutex);
988         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
989         mutex_unlock(&lower_dentry->d_inode->i_mutex);
990 out:
991         return rc;
992 }
993
994 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
995 {
996         if ((ecryptfs_inode_to_lower(inode)
997              == (struct inode *)candidate_lower_inode))
998                 return 1;
999         else
1000                 return 0;
1001 }
1002
1003 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1004 {
1005         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1006         return 0;
1007 }
1008
1009 struct inode_operations ecryptfs_symlink_iops = {
1010         .readlink = ecryptfs_readlink,
1011         .follow_link = ecryptfs_follow_link,
1012         .put_link = ecryptfs_put_link,
1013         .permission = ecryptfs_permission,
1014         .setattr = ecryptfs_setattr,
1015         .setxattr = ecryptfs_setxattr,
1016         .getxattr = ecryptfs_getxattr,
1017         .listxattr = ecryptfs_listxattr,
1018         .removexattr = ecryptfs_removexattr
1019 };
1020
1021 struct inode_operations ecryptfs_dir_iops = {
1022         .create = ecryptfs_create,
1023         .lookup = ecryptfs_lookup,
1024         .link = ecryptfs_link,
1025         .unlink = ecryptfs_unlink,
1026         .symlink = ecryptfs_symlink,
1027         .mkdir = ecryptfs_mkdir,
1028         .rmdir = ecryptfs_rmdir,
1029         .mknod = ecryptfs_mknod,
1030         .rename = ecryptfs_rename,
1031         .permission = ecryptfs_permission,
1032         .setattr = ecryptfs_setattr,
1033         .setxattr = ecryptfs_setxattr,
1034         .getxattr = ecryptfs_getxattr,
1035         .listxattr = ecryptfs_listxattr,
1036         .removexattr = ecryptfs_removexattr
1037 };
1038
1039 struct inode_operations ecryptfs_main_iops = {
1040         .permission = ecryptfs_permission,
1041         .setattr = ecryptfs_setattr,
1042         .setxattr = ecryptfs_setxattr,
1043         .getxattr = ecryptfs_getxattr,
1044         .listxattr = ecryptfs_listxattr,
1045         .removexattr = ecryptfs_removexattr
1046 };