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