Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq
[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) 2004-2007 International Business Machines Corp.
7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation; either version 2 of the
13  * License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23  * 02111-1307, USA.
24  */
25
26 #include <linux/file.h>
27 #include <linux/vmalloc.h>
28 #include <linux/pagemap.h>
29 #include <linux/dcache.h>
30 #include <linux/namei.h>
31 #include <linux/mount.h>
32 #include <linux/crypto.h>
33 #include <linux/fs_stack.h>
34 #include "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_inode_to_private(inode)->crypt_stat.flags |=
165                         ECRYPTFS_SECURITY_WARNING;
166                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
167                                 "in file; rc = [%d]\n", rc);
168                 goto out;
169         }
170         i_size_write(inode, 0);
171         ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode, inode,
172                                               ecryptfs_dentry,
173                                               ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
174         ecryptfs_inode_to_private(inode)->crypt_stat.flags |= 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_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                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
218                 goto out_fput;
219         }
220         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_metadata(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         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
291         char *page_virt = NULL;
292         struct inode *lower_inode;
293         u64 file_size;
294
295         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
296         dentry->d_op = &ecryptfs_dops;
297         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
298             || (dentry->d_name.len == 2
299                 && !strcmp(dentry->d_name.name, ".."))) {
300                 d_drop(dentry);
301                 goto out;
302         }
303         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
304                                                    dentry->d_name.name,
305                                                    dentry->d_name.len,
306                                                    &encoded_name);
307         if (encoded_namelen < 0) {
308                 rc = encoded_namelen;
309                 d_drop(dentry);
310                 goto out;
311         }
312         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
313                         "= [%d]\n", encoded_name, encoded_namelen);
314         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
315                                       encoded_namelen - 1);
316         kfree(encoded_name);
317         if (IS_ERR(lower_dentry)) {
318                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
319                 rc = PTR_ERR(lower_dentry);
320                 d_drop(dentry);
321                 goto out;
322         }
323         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
324         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
325                 "d_name.name = [%s]\n", lower_dentry,
326                 lower_dentry->d_name.name);
327         lower_inode = lower_dentry->d_inode;
328         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
329         BUG_ON(!atomic_read(&lower_dentry->d_count));
330         ecryptfs_set_dentry_private(dentry,
331                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
332                                                      GFP_KERNEL));
333         if (!ecryptfs_dentry_to_private(dentry)) {
334                 rc = -ENOMEM;
335                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
336                                 "to allocate ecryptfs_dentry_info struct\n");
337                 goto out_dput;
338         }
339         ecryptfs_set_dentry_lower(dentry, lower_dentry);
340         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
341         if (!lower_dentry->d_inode) {
342                 /* We want to add because we couldn't find in lower */
343                 d_add(dentry, NULL);
344                 goto out;
345         }
346         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
347         if (rc) {
348                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
349                 goto out_dput;
350         }
351         if (S_ISDIR(lower_inode->i_mode)) {
352                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
353                 goto out;
354         }
355         if (S_ISLNK(lower_inode->i_mode)) {
356                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
357                 goto out;
358         }
359         if (!nd) {
360                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
361                                 "as we *think* we are about to unlink\n");
362                 goto out;
363         }
364         /* Released in this function */
365         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
366                                       GFP_USER);
367         if (!page_virt) {
368                 rc = -ENOMEM;
369                 ecryptfs_printk(KERN_ERR,
370                                 "Cannot ecryptfs_kmalloc a page\n");
371                 goto out_dput;
372         }
373         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
374         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
375                 ecryptfs_set_default_sizes(crypt_stat);
376         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
377                                                       nd->mnt);
378         if (rc) {
379                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
380                 if (rc) {
381                         printk(KERN_DEBUG "Valid metadata not found in header "
382                                "region or xattr region; treating file as "
383                                "unencrypted\n");
384                         rc = 0;
385                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
386                         goto out;
387                 }
388                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
389         }
390         mount_crypt_stat = &ecryptfs_superblock_to_private(
391                 dentry->d_sb)->mount_crypt_stat;
392         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
393                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
394                         file_size = (crypt_stat->header_extent_size
395                                      + i_size_read(lower_dentry->d_inode));
396                 else
397                         file_size = i_size_read(lower_dentry->d_inode);
398         } else {
399                 memcpy(&file_size, page_virt, sizeof(file_size));
400                 file_size = be64_to_cpu(file_size);
401         }
402         i_size_write(dentry->d_inode, (loff_t)file_size);
403         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
404         goto out;
405
406 out_dput:
407         dput(lower_dentry);
408         d_drop(dentry);
409 out:
410         return ERR_PTR(rc);
411 }
412
413 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
414                          struct dentry *new_dentry)
415 {
416         struct dentry *lower_old_dentry;
417         struct dentry *lower_new_dentry;
418         struct dentry *lower_dir_dentry;
419         u64 file_size_save;
420         int rc;
421
422         file_size_save = i_size_read(old_dentry->d_inode);
423         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
424         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
425         dget(lower_old_dentry);
426         dget(lower_new_dentry);
427         lower_dir_dentry = lock_parent(lower_new_dentry);
428         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
429                       lower_new_dentry);
430         if (rc || !lower_new_dentry->d_inode)
431                 goto out_lock;
432         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
433         if (rc)
434                 goto out_lock;
435         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
436         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
437         old_dentry->d_inode->i_nlink =
438                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
439         i_size_write(new_dentry->d_inode, file_size_save);
440 out_lock:
441         unlock_dir(lower_dir_dentry);
442         dput(lower_new_dentry);
443         dput(lower_old_dentry);
444         d_drop(lower_old_dentry);
445         d_drop(new_dentry);
446         d_drop(old_dentry);
447         return rc;
448 }
449
450 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
451 {
452         int rc = 0;
453         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
454         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
455
456         lock_parent(lower_dentry);
457         rc = vfs_unlink(lower_dir_inode, lower_dentry);
458         if (rc) {
459                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
460                 goto out_unlock;
461         }
462         fsstack_copy_attr_times(dir, lower_dir_inode);
463         dentry->d_inode->i_nlink =
464                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
465         dentry->d_inode->i_ctime = dir->i_ctime;
466 out_unlock:
467         unlock_parent(lower_dentry);
468         return rc;
469 }
470
471 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
472                             const char *symname)
473 {
474         int rc;
475         struct dentry *lower_dentry;
476         struct dentry *lower_dir_dentry;
477         umode_t mode;
478         char *encoded_symname;
479         unsigned int encoded_symlen;
480         struct ecryptfs_crypt_stat *crypt_stat = NULL;
481
482         lower_dentry = ecryptfs_dentry_to_lower(dentry);
483         dget(lower_dentry);
484         lower_dir_dentry = lock_parent(lower_dentry);
485         mode = S_IALLUGO;
486         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
487                                                   strlen(symname),
488                                                   &encoded_symname);
489         if (encoded_symlen < 0) {
490                 rc = encoded_symlen;
491                 goto out_lock;
492         }
493         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
494                          encoded_symname, mode);
495         kfree(encoded_symname);
496         if (rc || !lower_dentry->d_inode)
497                 goto out_lock;
498         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
499         if (rc)
500                 goto out_lock;
501         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
502         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
503 out_lock:
504         unlock_dir(lower_dir_dentry);
505         dput(lower_dentry);
506         if (!dentry->d_inode)
507                 d_drop(dentry);
508         return rc;
509 }
510
511 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
512 {
513         int rc;
514         struct dentry *lower_dentry;
515         struct dentry *lower_dir_dentry;
516
517         lower_dentry = ecryptfs_dentry_to_lower(dentry);
518         lower_dir_dentry = lock_parent(lower_dentry);
519         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
520         if (rc || !lower_dentry->d_inode)
521                 goto out;
522         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
523         if (rc)
524                 goto out;
525         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
526         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
527         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
528 out:
529         unlock_dir(lower_dir_dentry);
530         if (!dentry->d_inode)
531                 d_drop(dentry);
532         return rc;
533 }
534
535 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
536 {
537         struct dentry *lower_dentry;
538         struct dentry *lower_dir_dentry;
539         int rc;
540
541         lower_dentry = ecryptfs_dentry_to_lower(dentry);
542         dget(dentry);
543         lower_dir_dentry = lock_parent(lower_dentry);
544         dget(lower_dentry);
545         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
546         dput(lower_dentry);
547         if (!rc)
548                 d_delete(lower_dentry);
549         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
550         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
551         unlock_dir(lower_dir_dentry);
552         if (!rc)
553                 d_drop(dentry);
554         dput(dentry);
555         return rc;
556 }
557
558 static int
559 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
560 {
561         int rc;
562         struct dentry *lower_dentry;
563         struct dentry *lower_dir_dentry;
564
565         lower_dentry = ecryptfs_dentry_to_lower(dentry);
566         lower_dir_dentry = lock_parent(lower_dentry);
567         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
568         if (rc || !lower_dentry->d_inode)
569                 goto out;
570         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
571         if (rc)
572                 goto out;
573         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
574         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
575 out:
576         unlock_dir(lower_dir_dentry);
577         if (!dentry->d_inode)
578                 d_drop(dentry);
579         return rc;
580 }
581
582 static int
583 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
584                 struct inode *new_dir, struct dentry *new_dentry)
585 {
586         int rc;
587         struct dentry *lower_old_dentry;
588         struct dentry *lower_new_dentry;
589         struct dentry *lower_old_dir_dentry;
590         struct dentry *lower_new_dir_dentry;
591
592         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
593         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
594         dget(lower_old_dentry);
595         dget(lower_new_dentry);
596         lower_old_dir_dentry = dget_parent(lower_old_dentry);
597         lower_new_dir_dentry = dget_parent(lower_new_dentry);
598         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
599         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
600                         lower_new_dir_dentry->d_inode, lower_new_dentry);
601         if (rc)
602                 goto out_lock;
603         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
604         if (new_dir != old_dir)
605                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
606 out_lock:
607         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
608         dput(lower_new_dentry->d_parent);
609         dput(lower_old_dentry->d_parent);
610         dput(lower_new_dentry);
611         dput(lower_old_dentry);
612         return rc;
613 }
614
615 static int
616 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
617 {
618         int rc;
619         struct dentry *lower_dentry;
620         char *decoded_name;
621         char *lower_buf;
622         mm_segment_t old_fs;
623         struct ecryptfs_crypt_stat *crypt_stat;
624
625         lower_dentry = ecryptfs_dentry_to_lower(dentry);
626         if (!lower_dentry->d_inode->i_op ||
627             !lower_dentry->d_inode->i_op->readlink) {
628                 rc = -EINVAL;
629                 goto out;
630         }
631         /* Released in this function */
632         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
633         if (lower_buf == NULL) {
634                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
635                 rc = -ENOMEM;
636                 goto out;
637         }
638         old_fs = get_fs();
639         set_fs(get_ds());
640         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
641                         "lower_dentry->d_name.name = [%s]\n",
642                         lower_dentry->d_name.name);
643         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
644                                                    (char __user *)lower_buf,
645                                                    bufsiz);
646         set_fs(old_fs);
647         if (rc >= 0) {
648                 crypt_stat = NULL;
649                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
650                                               &decoded_name);
651                 if (rc == -ENOMEM)
652                         goto out_free_lower_buf;
653                 if (rc > 0) {
654                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
655                                         "to userspace: [%*s]\n", rc,
656                                         decoded_name);
657                         if (copy_to_user(buf, decoded_name, rc))
658                                 rc = -EFAULT;
659                 }
660                 kfree(decoded_name);
661                 fsstack_copy_attr_atime(dentry->d_inode,
662                                         lower_dentry->d_inode);
663         }
664 out_free_lower_buf:
665         kfree(lower_buf);
666 out:
667         return rc;
668 }
669
670 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
671 {
672         char *buf;
673         int len = PAGE_SIZE, rc;
674         mm_segment_t old_fs;
675
676         /* Released in ecryptfs_put_link(); only release here on error */
677         buf = kmalloc(len, GFP_KERNEL);
678         if (!buf) {
679                 rc = -ENOMEM;
680                 goto out;
681         }
682         old_fs = get_fs();
683         set_fs(get_ds());
684         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
685                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
686         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
687         buf[rc] = '\0';
688         set_fs(old_fs);
689         if (rc < 0)
690                 goto out_free;
691         rc = 0;
692         nd_set_link(nd, buf);
693         goto out;
694 out_free:
695         kfree(buf);
696 out:
697         return ERR_PTR(rc);
698 }
699
700 static void
701 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
702 {
703         /* Free the char* */
704         kfree(nd_get_link(nd));
705 }
706
707 /**
708  * upper_size_to_lower_size
709  * @crypt_stat: Crypt_stat associated with file
710  * @upper_size: Size of the upper file
711  *
712  * Calculate the requried size of the lower file based on the
713  * specified size of the upper file. This calculation is based on the
714  * number of headers in the underlying file and the extent size.
715  *
716  * Returns Calculated size of the lower file.
717  */
718 static loff_t
719 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
720                          loff_t upper_size)
721 {
722         loff_t lower_size;
723
724         lower_size = ( crypt_stat->header_extent_size
725                        * crypt_stat->num_header_extents_at_front );
726         if (upper_size != 0) {
727                 loff_t num_extents;
728
729                 num_extents = upper_size >> crypt_stat->extent_shift;
730                 if (upper_size & ~crypt_stat->extent_mask)
731                         num_extents++;
732                 lower_size += (num_extents * crypt_stat->extent_size);
733         }
734         return lower_size;
735 }
736
737 /**
738  * ecryptfs_truncate
739  * @dentry: The ecryptfs layer dentry
740  * @new_length: The length to expand the file to
741  *
742  * Function to handle truncations modifying the size of the file. Note
743  * that the file sizes are interpolated. When expanding, we are simply
744  * writing strings of 0's out. When truncating, we need to modify the
745  * underlying file size according to the page index interpolations.
746  *
747  * Returns zero on success; non-zero otherwise
748  */
749 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
750 {
751         int rc = 0;
752         struct inode *inode = dentry->d_inode;
753         struct dentry *lower_dentry;
754         struct vfsmount *lower_mnt;
755         struct file fake_ecryptfs_file, *lower_file = NULL;
756         struct ecryptfs_crypt_stat *crypt_stat;
757         loff_t i_size = i_size_read(inode);
758         loff_t lower_size_before_truncate;
759         loff_t lower_size_after_truncate;
760
761         if (unlikely((new_length == i_size)))
762                 goto out;
763         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
764         /* Set up a fake ecryptfs file, this is used to interface with
765          * the file in the underlying filesystem so that the
766          * truncation has an effect there as well. */
767         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
768         fake_ecryptfs_file.f_path.dentry = dentry;
769         /* Released at out_free: label */
770         ecryptfs_set_file_private(&fake_ecryptfs_file,
771                                   kmem_cache_alloc(ecryptfs_file_info_cache,
772                                                    GFP_KERNEL));
773         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
774                 rc = -ENOMEM;
775                 goto out;
776         }
777         lower_dentry = ecryptfs_dentry_to_lower(dentry);
778         /* This dget & mntget is released through fput at out_fput: */
779         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
780         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
781                                            O_RDWR))) {
782                 ecryptfs_printk(KERN_ERR,
783                                 "Error opening dentry; rc = [%i]\n", rc);
784                 goto out_free;
785         }
786         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
787         /* Switch on growing or shrinking file */
788         if (new_length > i_size) {
789                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
790                 if (rc) {
791                         ecryptfs_printk(KERN_ERR,
792                                         "Problem with fill_zeros\n");
793                         goto out_fput;
794                 }
795                 i_size_write(inode, new_length);
796                 rc = ecryptfs_write_inode_size_to_metadata(
797                         lower_file, lower_dentry->d_inode, inode, dentry,
798                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
799                 if (rc) {
800                         printk(KERN_ERR "Problem with "
801                                "ecryptfs_write_inode_size_to_metadata; "
802                                "rc = [%d]\n", rc);
803                         goto out_fput;
804                 }
805         } else { /* new_length < i_size_read(inode) */
806                 vmtruncate(inode, new_length);
807                 rc = ecryptfs_write_inode_size_to_metadata(
808                         lower_file, lower_dentry->d_inode, inode, dentry,
809                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
810                 if (rc) {
811                         printk(KERN_ERR "Problem with "
812                                "ecryptfs_write_inode_size_to_metadata; "
813                                "rc = [%d]\n", rc);
814                         goto out_fput;
815                 }
816                 /* We are reducing the size of the ecryptfs file, and need to
817                  * know if we need to reduce the size of the lower file. */
818                 lower_size_before_truncate =
819                     upper_size_to_lower_size(crypt_stat, i_size);
820                 lower_size_after_truncate =
821                     upper_size_to_lower_size(crypt_stat, new_length);
822                 if (lower_size_after_truncate < lower_size_before_truncate)
823                         vmtruncate(lower_dentry->d_inode,
824                                    lower_size_after_truncate);
825         }
826         /* Update the access times */
827         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
828                 = CURRENT_TIME;
829         mark_inode_dirty_sync(inode);
830 out_fput:
831         if ((rc = ecryptfs_close_lower_file(lower_file)))
832                 printk(KERN_ERR "Error closing lower_file\n");
833 out_free:
834         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
835                 kmem_cache_free(ecryptfs_file_info_cache,
836                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
837 out:
838         return rc;
839 }
840
841 static int
842 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
843 {
844         int rc;
845
846         if (nd) {
847                 struct vfsmount *vfsmnt_save = nd->mnt;
848                 struct dentry *dentry_save = nd->dentry;
849
850                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
851                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
852                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
853                 nd->mnt = vfsmnt_save;
854                 nd->dentry = dentry_save;
855         } else
856                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
857         return rc;
858 }
859
860 /**
861  * ecryptfs_setattr
862  * @dentry: dentry handle to the inode to modify
863  * @ia: Structure with flags of what to change and values
864  *
865  * Updates the metadata of an inode. If the update is to the size
866  * i.e. truncation, then ecryptfs_truncate will handle the size modification
867  * of both the ecryptfs inode and the lower inode.
868  *
869  * All other metadata changes will be passed right to the lower filesystem,
870  * and we will just update our inode to look like the lower.
871  */
872 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
873 {
874         int rc = 0;
875         struct dentry *lower_dentry;
876         struct inode *inode;
877         struct inode *lower_inode;
878         struct ecryptfs_crypt_stat *crypt_stat;
879
880         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
881         lower_dentry = ecryptfs_dentry_to_lower(dentry);
882         inode = dentry->d_inode;
883         lower_inode = ecryptfs_inode_to_lower(inode);
884         if (ia->ia_valid & ATTR_SIZE) {
885                 ecryptfs_printk(KERN_DEBUG,
886                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
887                                 ia->ia_valid, ATTR_SIZE);
888                 rc = ecryptfs_truncate(dentry, ia->ia_size);
889                 /* ecryptfs_truncate handles resizing of the lower file */
890                 ia->ia_valid &= ~ATTR_SIZE;
891                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
892                                 ia->ia_valid);
893                 if (rc < 0)
894                         goto out;
895         }
896         rc = notify_change(lower_dentry, ia);
897 out:
898         fsstack_copy_attr_all(inode, lower_inode, NULL);
899         return rc;
900 }
901
902 int
903 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
904                   size_t size, int flags)
905 {
906         int rc = 0;
907         struct dentry *lower_dentry;
908
909         lower_dentry = ecryptfs_dentry_to_lower(dentry);
910         if (!lower_dentry->d_inode->i_op->setxattr) {
911                 rc = -ENOSYS;
912                 goto out;
913         }
914         mutex_lock(&lower_dentry->d_inode->i_mutex);
915         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
916                                                    size, flags);
917         mutex_unlock(&lower_dentry->d_inode->i_mutex);
918 out:
919         return rc;
920 }
921
922 ssize_t
923 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
924                   size_t size)
925 {
926         int rc = 0;
927         struct dentry *lower_dentry;
928
929         lower_dentry = ecryptfs_dentry_to_lower(dentry);
930         if (!lower_dentry->d_inode->i_op->getxattr) {
931                 rc = -ENOSYS;
932                 goto out;
933         }
934         mutex_lock(&lower_dentry->d_inode->i_mutex);
935         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
936                                                    size);
937         mutex_unlock(&lower_dentry->d_inode->i_mutex);
938 out:
939         return rc;
940 }
941
942 static ssize_t
943 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
944 {
945         int rc = 0;
946         struct dentry *lower_dentry;
947
948         lower_dentry = ecryptfs_dentry_to_lower(dentry);
949         if (!lower_dentry->d_inode->i_op->listxattr) {
950                 rc = -ENOSYS;
951                 goto out;
952         }
953         mutex_lock(&lower_dentry->d_inode->i_mutex);
954         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
955         mutex_unlock(&lower_dentry->d_inode->i_mutex);
956 out:
957         return rc;
958 }
959
960 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
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->removexattr) {
967                 rc = -ENOSYS;
968                 goto out;
969         }
970         mutex_lock(&lower_dentry->d_inode->i_mutex);
971         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
972         mutex_unlock(&lower_dentry->d_inode->i_mutex);
973 out:
974         return rc;
975 }
976
977 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
978 {
979         if ((ecryptfs_inode_to_lower(inode)
980              == (struct inode *)candidate_lower_inode))
981                 return 1;
982         else
983                 return 0;
984 }
985
986 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
987 {
988         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
989         return 0;
990 }
991
992 const struct inode_operations ecryptfs_symlink_iops = {
993         .readlink = ecryptfs_readlink,
994         .follow_link = ecryptfs_follow_link,
995         .put_link = ecryptfs_put_link,
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 const struct inode_operations ecryptfs_dir_iops = {
1005         .create = ecryptfs_create,
1006         .lookup = ecryptfs_lookup,
1007         .link = ecryptfs_link,
1008         .unlink = ecryptfs_unlink,
1009         .symlink = ecryptfs_symlink,
1010         .mkdir = ecryptfs_mkdir,
1011         .rmdir = ecryptfs_rmdir,
1012         .mknod = ecryptfs_mknod,
1013         .rename = ecryptfs_rename,
1014         .permission = ecryptfs_permission,
1015         .setattr = ecryptfs_setattr,
1016         .setxattr = ecryptfs_setxattr,
1017         .getxattr = ecryptfs_getxattr,
1018         .listxattr = ecryptfs_listxattr,
1019         .removexattr = ecryptfs_removexattr
1020 };
1021
1022 const struct inode_operations ecryptfs_main_iops = {
1023         .permission = ecryptfs_permission,
1024         .setattr = ecryptfs_setattr,
1025         .setxattr = ecryptfs_setxattr,
1026         .getxattr = ecryptfs_getxattr,
1027         .listxattr = ecryptfs_listxattr,
1028         .removexattr = ecryptfs_removexattr
1029 };