1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /**
3 * eCryptfs: Linux filesystem encryption layer
4 *
5 * Copyright (C) 1997-2004 Erez Zadok
6 * Copyright (C) 2001-2004 Stony Brook University
7 * Copyright (C) 2004-2007 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
9 * Michael C. Thompsion <mcthomps@us.ibm.com>
10 */
11
12 #include <linux/file.h>
13 #include <linux/vmalloc.h>
14 #include <linux/pagemap.h>
15 #include <linux/dcache.h>
16 #include <linux/namei.h>
17 #include <linux/mount.h>
18 #include <linux/fs_stack.h>
19 #include <linux/slab.h>
20 #include <linux/xattr.h>
21 #include <asm/unaligned.h>
22 #include "ecryptfs_kernel.h"
23
lock_parent(struct dentry * dentry)24 static struct dentry *lock_parent(struct dentry *dentry)
25 {
26 struct dentry *dir;
27
28 dir = dget_parent(dentry);
29 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
30 return dir;
31 }
32
unlock_dir(struct dentry * dir)33 static void unlock_dir(struct dentry *dir)
34 {
35 inode_unlock(d_inode(dir));
36 dput(dir);
37 }
38
ecryptfs_inode_test(struct inode * inode,void * lower_inode)39 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
40 {
41 return ecryptfs_inode_to_lower(inode) == lower_inode;
42 }
43
ecryptfs_inode_set(struct inode * inode,void * opaque)44 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
45 {
46 struct inode *lower_inode = opaque;
47
48 ecryptfs_set_inode_lower(inode, lower_inode);
49 fsstack_copy_attr_all(inode, lower_inode);
50 /* i_size will be overwritten for encrypted regular files */
51 fsstack_copy_inode_size(inode, lower_inode);
52 inode->i_ino = lower_inode->i_ino;
53 inode->i_mapping->a_ops = &ecryptfs_aops;
54
55 if (S_ISLNK(inode->i_mode))
56 inode->i_op = &ecryptfs_symlink_iops;
57 else if (S_ISDIR(inode->i_mode))
58 inode->i_op = &ecryptfs_dir_iops;
59 else
60 inode->i_op = &ecryptfs_main_iops;
61
62 if (S_ISDIR(inode->i_mode))
63 inode->i_fop = &ecryptfs_dir_fops;
64 else if (special_file(inode->i_mode))
65 init_special_inode(inode, inode->i_mode, inode->i_rdev);
66 else
67 inode->i_fop = &ecryptfs_main_fops;
68
69 return 0;
70 }
71
__ecryptfs_get_inode(struct inode * lower_inode,struct super_block * sb)72 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
73 struct super_block *sb)
74 {
75 struct inode *inode;
76
77 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
78 return ERR_PTR(-EXDEV);
79
80 /* Reject dealing with casefold directories. */
81 if (IS_CASEFOLDED(lower_inode)) {
82 pr_err_ratelimited("%s: Can't handle casefolded directory.\n",
83 __func__);
84 return ERR_PTR(-EREMOTE);
85 }
86
87 if (!igrab(lower_inode))
88 return ERR_PTR(-ESTALE);
89 inode = iget5_locked(sb, (unsigned long)lower_inode,
90 ecryptfs_inode_test, ecryptfs_inode_set,
91 lower_inode);
92 if (!inode) {
93 iput(lower_inode);
94 return ERR_PTR(-EACCES);
95 }
96 if (!(inode->i_state & I_NEW))
97 iput(lower_inode);
98
99 return inode;
100 }
101
ecryptfs_get_inode(struct inode * lower_inode,struct super_block * sb)102 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
103 struct super_block *sb)
104 {
105 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
106
107 if (!IS_ERR(inode) && (inode->i_state & I_NEW))
108 unlock_new_inode(inode);
109
110 return inode;
111 }
112
113 /**
114 * ecryptfs_interpose
115 * @lower_dentry: Existing dentry in the lower filesystem
116 * @dentry: ecryptfs' dentry
117 * @sb: ecryptfs's super_block
118 *
119 * Interposes upper and lower dentries.
120 *
121 * Returns zero on success; non-zero otherwise
122 */
ecryptfs_interpose(struct dentry * lower_dentry,struct dentry * dentry,struct super_block * sb)123 static int ecryptfs_interpose(struct dentry *lower_dentry,
124 struct dentry *dentry, struct super_block *sb)
125 {
126 struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
127
128 if (IS_ERR(inode))
129 return PTR_ERR(inode);
130 d_instantiate(dentry, inode);
131
132 return 0;
133 }
134
ecryptfs_do_unlink(struct inode * dir,struct dentry * dentry,struct inode * inode)135 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
136 struct inode *inode)
137 {
138 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
139 struct dentry *lower_dir_dentry;
140 struct inode *lower_dir_inode;
141 int rc;
142
143 lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
144 lower_dir_inode = d_inode(lower_dir_dentry);
145 inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
146 dget(lower_dentry); // don't even try to make the lower negative
147 if (lower_dentry->d_parent != lower_dir_dentry)
148 rc = -EINVAL;
149 else if (d_unhashed(lower_dentry))
150 rc = -EINVAL;
151 else
152 rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
153 if (rc) {
154 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
155 goto out_unlock;
156 }
157 fsstack_copy_attr_times(dir, lower_dir_inode);
158 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
159 inode->i_ctime = dir->i_ctime;
160 out_unlock:
161 dput(lower_dentry);
162 inode_unlock(lower_dir_inode);
163 if (!rc)
164 d_drop(dentry);
165 return rc;
166 }
167
168 /**
169 * ecryptfs_do_create
170 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
171 * @ecryptfs_dentry: New file's dentry in ecryptfs
172 * @mode: The mode of the new file
173 *
174 * Creates the underlying file and the eCryptfs inode which will link to
175 * it. It will also update the eCryptfs directory inode to mimic the
176 * stat of the lower directory inode.
177 *
178 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
179 */
180 static struct inode *
ecryptfs_do_create(struct inode * directory_inode,struct dentry * ecryptfs_dentry,umode_t mode)181 ecryptfs_do_create(struct inode *directory_inode,
182 struct dentry *ecryptfs_dentry, umode_t mode)
183 {
184 int rc;
185 struct dentry *lower_dentry;
186 struct dentry *lower_dir_dentry;
187 struct inode *inode;
188
189 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
190 lower_dir_dentry = lock_parent(lower_dentry);
191 rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
192 if (rc) {
193 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
194 "rc = [%d]\n", __func__, rc);
195 inode = ERR_PTR(rc);
196 goto out_lock;
197 }
198 inode = __ecryptfs_get_inode(d_inode(lower_dentry),
199 directory_inode->i_sb);
200 if (IS_ERR(inode)) {
201 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
202 goto out_lock;
203 }
204 fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
205 fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
206 out_lock:
207 unlock_dir(lower_dir_dentry);
208 return inode;
209 }
210
211 /**
212 * ecryptfs_initialize_file
213 *
214 * Cause the file to be changed from a basic empty file to an ecryptfs
215 * file with a header and first data page.
216 *
217 * Returns zero on success
218 */
ecryptfs_initialize_file(struct dentry * ecryptfs_dentry,struct inode * ecryptfs_inode)219 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
220 struct inode *ecryptfs_inode)
221 {
222 struct ecryptfs_crypt_stat *crypt_stat =
223 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
224 int rc = 0;
225
226 if (S_ISDIR(ecryptfs_inode->i_mode)) {
227 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
228 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
229 goto out;
230 }
231 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
232 rc = ecryptfs_new_file_context(ecryptfs_inode);
233 if (rc) {
234 ecryptfs_printk(KERN_ERR, "Error creating new file "
235 "context; rc = [%d]\n", rc);
236 goto out;
237 }
238 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
239 if (rc) {
240 printk(KERN_ERR "%s: Error attempting to initialize "
241 "the lower file for the dentry with name "
242 "[%pd]; rc = [%d]\n", __func__,
243 ecryptfs_dentry, rc);
244 goto out;
245 }
246 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
247 if (rc)
248 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
249 ecryptfs_put_lower_file(ecryptfs_inode);
250 out:
251 return rc;
252 }
253
254 /**
255 * ecryptfs_create
256 * @dir: The inode of the directory in which to create the file.
257 * @dentry: The eCryptfs dentry
258 * @mode: The mode of the new file.
259 *
260 * Creates a new file.
261 *
262 * Returns zero on success; non-zero on error condition
263 */
264 static int
ecryptfs_create(struct inode * directory_inode,struct dentry * ecryptfs_dentry,umode_t mode,bool excl)265 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
266 umode_t mode, bool excl)
267 {
268 struct inode *ecryptfs_inode;
269 int rc;
270
271 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
272 mode);
273 if (IS_ERR(ecryptfs_inode)) {
274 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
275 "lower filesystem\n");
276 rc = PTR_ERR(ecryptfs_inode);
277 goto out;
278 }
279 /* At this point, a file exists on "disk"; we need to make sure
280 * that this on disk file is prepared to be an ecryptfs file */
281 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
282 if (rc) {
283 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
284 ecryptfs_inode);
285 iget_failed(ecryptfs_inode);
286 goto out;
287 }
288 d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
289 out:
290 return rc;
291 }
292
ecryptfs_i_size_read(struct dentry * dentry,struct inode * inode)293 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
294 {
295 struct ecryptfs_crypt_stat *crypt_stat;
296 int rc;
297
298 rc = ecryptfs_get_lower_file(dentry, inode);
299 if (rc) {
300 printk(KERN_ERR "%s: Error attempting to initialize "
301 "the lower file for the dentry with name "
302 "[%pd]; rc = [%d]\n", __func__,
303 dentry, rc);
304 return rc;
305 }
306
307 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
308 /* TODO: lock for crypt_stat comparison */
309 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
310 ecryptfs_set_default_sizes(crypt_stat);
311
312 rc = ecryptfs_read_and_validate_header_region(inode);
313 ecryptfs_put_lower_file(inode);
314 if (rc) {
315 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
316 if (!rc)
317 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
318 }
319
320 /* Must return 0 to allow non-eCryptfs files to be looked up, too */
321 return 0;
322 }
323
324 /**
325 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
326 */
ecryptfs_lookup_interpose(struct dentry * dentry,struct dentry * lower_dentry)327 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
328 struct dentry *lower_dentry)
329 {
330 struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
331 struct inode *inode, *lower_inode;
332 struct ecryptfs_dentry_info *dentry_info;
333 int rc = 0;
334
335 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
336 if (!dentry_info) {
337 dput(lower_dentry);
338 return ERR_PTR(-ENOMEM);
339 }
340
341 fsstack_copy_attr_atime(d_inode(dentry->d_parent),
342 d_inode(path->dentry));
343 BUG_ON(!d_count(lower_dentry));
344
345 ecryptfs_set_dentry_private(dentry, dentry_info);
346 dentry_info->lower_path.mnt = mntget(path->mnt);
347 dentry_info->lower_path.dentry = lower_dentry;
348
349 /*
350 * negative dentry can go positive under us here - its parent is not
351 * locked. That's OK and that could happen just as we return from
352 * ecryptfs_lookup() anyway. Just need to be careful and fetch
353 * ->d_inode only once - it's not stable here.
354 */
355 lower_inode = READ_ONCE(lower_dentry->d_inode);
356
357 if (!lower_inode) {
358 /* We want to add because we couldn't find in lower */
359 d_add(dentry, NULL);
360 return NULL;
361 }
362 inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
363 if (IS_ERR(inode)) {
364 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
365 __func__, PTR_ERR(inode));
366 return ERR_CAST(inode);
367 }
368 if (S_ISREG(inode->i_mode)) {
369 rc = ecryptfs_i_size_read(dentry, inode);
370 if (rc) {
371 make_bad_inode(inode);
372 return ERR_PTR(rc);
373 }
374 }
375
376 if (inode->i_state & I_NEW)
377 unlock_new_inode(inode);
378 return d_splice_alias(inode, dentry);
379 }
380
381 /**
382 * ecryptfs_lookup
383 * @ecryptfs_dir_inode: The eCryptfs directory inode
384 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
385 * @flags: lookup flags
386 *
387 * Find a file on disk. If the file does not exist, then we'll add it to the
388 * dentry cache and continue on to read it from the disk.
389 */
ecryptfs_lookup(struct inode * ecryptfs_dir_inode,struct dentry * ecryptfs_dentry,unsigned int flags)390 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
391 struct dentry *ecryptfs_dentry,
392 unsigned int flags)
393 {
394 char *encrypted_and_encoded_name = NULL;
395 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
396 struct dentry *lower_dir_dentry, *lower_dentry;
397 const char *name = ecryptfs_dentry->d_name.name;
398 size_t len = ecryptfs_dentry->d_name.len;
399 struct dentry *res;
400 int rc = 0;
401
402 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
403
404 mount_crypt_stat = &ecryptfs_superblock_to_private(
405 ecryptfs_dentry->d_sb)->mount_crypt_stat;
406 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
407 rc = ecryptfs_encrypt_and_encode_filename(
408 &encrypted_and_encoded_name, &len,
409 mount_crypt_stat, name, len);
410 if (rc) {
411 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
412 "filename; rc = [%d]\n", __func__, rc);
413 return ERR_PTR(rc);
414 }
415 name = encrypted_and_encoded_name;
416 }
417
418 lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
419 if (IS_ERR(lower_dentry)) {
420 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
421 "[%ld] on lower_dentry = [%s]\n", __func__,
422 PTR_ERR(lower_dentry),
423 name);
424 res = ERR_CAST(lower_dentry);
425 } else {
426 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
427 }
428 kfree(encrypted_and_encoded_name);
429 return res;
430 }
431
ecryptfs_link(struct dentry * old_dentry,struct inode * dir,struct dentry * new_dentry)432 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
433 struct dentry *new_dentry)
434 {
435 struct dentry *lower_old_dentry;
436 struct dentry *lower_new_dentry;
437 struct dentry *lower_dir_dentry;
438 u64 file_size_save;
439 int rc;
440
441 file_size_save = i_size_read(d_inode(old_dentry));
442 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
443 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
444 dget(lower_old_dentry);
445 dget(lower_new_dentry);
446 lower_dir_dentry = lock_parent(lower_new_dentry);
447 rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
448 lower_new_dentry, NULL);
449 if (rc || d_really_is_negative(lower_new_dentry))
450 goto out_lock;
451 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
452 if (rc)
453 goto out_lock;
454 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
455 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
456 set_nlink(d_inode(old_dentry),
457 ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
458 i_size_write(d_inode(new_dentry), file_size_save);
459 out_lock:
460 unlock_dir(lower_dir_dentry);
461 dput(lower_new_dentry);
462 dput(lower_old_dentry);
463 return rc;
464 }
465
ecryptfs_unlink(struct inode * dir,struct dentry * dentry)466 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
467 {
468 return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
469 }
470
ecryptfs_symlink(struct inode * dir,struct dentry * dentry,const char * symname)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 char *encoded_symname;
478 size_t encoded_symlen;
479 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
480
481 lower_dentry = ecryptfs_dentry_to_lower(dentry);
482 dget(lower_dentry);
483 lower_dir_dentry = lock_parent(lower_dentry);
484 mount_crypt_stat = &ecryptfs_superblock_to_private(
485 dir->i_sb)->mount_crypt_stat;
486 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
487 &encoded_symlen,
488 mount_crypt_stat, symname,
489 strlen(symname));
490 if (rc)
491 goto out_lock;
492 rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
493 encoded_symname);
494 kfree(encoded_symname);
495 if (rc || d_really_is_negative(lower_dentry))
496 goto out_lock;
497 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
498 if (rc)
499 goto out_lock;
500 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
501 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
502 out_lock:
503 unlock_dir(lower_dir_dentry);
504 dput(lower_dentry);
505 if (d_really_is_negative(dentry))
506 d_drop(dentry);
507 return rc;
508 }
509
ecryptfs_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)510 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
511 {
512 int rc;
513 struct dentry *lower_dentry;
514 struct dentry *lower_dir_dentry;
515
516 lower_dentry = ecryptfs_dentry_to_lower(dentry);
517 lower_dir_dentry = lock_parent(lower_dentry);
518 rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
519 if (rc || d_really_is_negative(lower_dentry))
520 goto out;
521 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
522 if (rc)
523 goto out;
524 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
525 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
526 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
527 out:
528 unlock_dir(lower_dir_dentry);
529 if (d_really_is_negative(dentry))
530 d_drop(dentry);
531 return rc;
532 }
533
ecryptfs_rmdir(struct inode * dir,struct dentry * dentry)534 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
535 {
536 struct dentry *lower_dentry;
537 struct dentry *lower_dir_dentry;
538 struct inode *lower_dir_inode;
539 int rc;
540
541 lower_dentry = ecryptfs_dentry_to_lower(dentry);
542 lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
543 lower_dir_inode = d_inode(lower_dir_dentry);
544
545 inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
546 dget(lower_dentry); // don't even try to make the lower negative
547 if (lower_dentry->d_parent != lower_dir_dentry)
548 rc = -EINVAL;
549 else if (d_unhashed(lower_dentry))
550 rc = -EINVAL;
551 else
552 rc = vfs_rmdir(lower_dir_inode, lower_dentry);
553 if (!rc) {
554 clear_nlink(d_inode(dentry));
555 fsstack_copy_attr_times(dir, lower_dir_inode);
556 set_nlink(dir, lower_dir_inode->i_nlink);
557 }
558 dput(lower_dentry);
559 inode_unlock(lower_dir_inode);
560 if (!rc)
561 d_drop(dentry);
562 return rc;
563 }
564
565 static int
ecryptfs_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t dev)566 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
567 {
568 int rc;
569 struct dentry *lower_dentry;
570 struct dentry *lower_dir_dentry;
571
572 lower_dentry = ecryptfs_dentry_to_lower(dentry);
573 lower_dir_dentry = lock_parent(lower_dentry);
574 rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
575 if (rc || d_really_is_negative(lower_dentry))
576 goto out;
577 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
578 if (rc)
579 goto out;
580 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
581 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
582 out:
583 unlock_dir(lower_dir_dentry);
584 if (d_really_is_negative(dentry))
585 d_drop(dentry);
586 return rc;
587 }
588
589 static int
ecryptfs_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)590 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
591 struct inode *new_dir, struct dentry *new_dentry,
592 unsigned int flags)
593 {
594 int rc;
595 struct dentry *lower_old_dentry;
596 struct dentry *lower_new_dentry;
597 struct dentry *lower_old_dir_dentry;
598 struct dentry *lower_new_dir_dentry;
599 struct dentry *trap;
600 struct inode *target_inode;
601
602 if (flags)
603 return -EINVAL;
604
605 lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent);
606 lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent);
607
608 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
609 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
610
611 target_inode = d_inode(new_dentry);
612
613 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
614 dget(lower_new_dentry);
615 rc = -EINVAL;
616 if (lower_old_dentry->d_parent != lower_old_dir_dentry)
617 goto out_lock;
618 if (lower_new_dentry->d_parent != lower_new_dir_dentry)
619 goto out_lock;
620 if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
621 goto out_lock;
622 /* source should not be ancestor of target */
623 if (trap == lower_old_dentry)
624 goto out_lock;
625 /* target should not be ancestor of source */
626 if (trap == lower_new_dentry) {
627 rc = -ENOTEMPTY;
628 goto out_lock;
629 }
630 rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
631 d_inode(lower_new_dir_dentry), lower_new_dentry,
632 NULL, 0);
633 if (rc)
634 goto out_lock;
635 if (target_inode)
636 fsstack_copy_attr_all(target_inode,
637 ecryptfs_inode_to_lower(target_inode));
638 fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
639 if (new_dir != old_dir)
640 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
641 out_lock:
642 dput(lower_new_dentry);
643 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
644 return rc;
645 }
646
ecryptfs_readlink_lower(struct dentry * dentry,size_t * bufsiz)647 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
648 {
649 DEFINE_DELAYED_CALL(done);
650 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
651 const char *link;
652 char *buf;
653 int rc;
654
655 link = vfs_get_link(lower_dentry, &done);
656 if (IS_ERR(link))
657 return ERR_CAST(link);
658
659 rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
660 link, strlen(link));
661 do_delayed_call(&done);
662 if (rc)
663 return ERR_PTR(rc);
664
665 return buf;
666 }
667
ecryptfs_get_link(struct dentry * dentry,struct inode * inode,struct delayed_call * done)668 static const char *ecryptfs_get_link(struct dentry *dentry,
669 struct inode *inode,
670 struct delayed_call *done)
671 {
672 size_t len;
673 char *buf;
674
675 if (!dentry)
676 return ERR_PTR(-ECHILD);
677
678 buf = ecryptfs_readlink_lower(dentry, &len);
679 if (IS_ERR(buf))
680 return buf;
681 fsstack_copy_attr_atime(d_inode(dentry),
682 d_inode(ecryptfs_dentry_to_lower(dentry)));
683 buf[len] = '\0';
684 set_delayed_call(done, kfree_link, buf);
685 return buf;
686 }
687
688 /**
689 * upper_size_to_lower_size
690 * @crypt_stat: Crypt_stat associated with file
691 * @upper_size: Size of the upper file
692 *
693 * Calculate the required size of the lower file based on the
694 * specified size of the upper file. This calculation is based on the
695 * number of headers in the underlying file and the extent size.
696 *
697 * Returns Calculated size of the lower file.
698 */
699 static loff_t
upper_size_to_lower_size(struct ecryptfs_crypt_stat * crypt_stat,loff_t upper_size)700 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
701 loff_t upper_size)
702 {
703 loff_t lower_size;
704
705 lower_size = ecryptfs_lower_header_size(crypt_stat);
706 if (upper_size != 0) {
707 loff_t num_extents;
708
709 num_extents = upper_size >> crypt_stat->extent_shift;
710 if (upper_size & ~crypt_stat->extent_mask)
711 num_extents++;
712 lower_size += (num_extents * crypt_stat->extent_size);
713 }
714 return lower_size;
715 }
716
717 /**
718 * truncate_upper
719 * @dentry: The ecryptfs layer dentry
720 * @ia: Address of the ecryptfs inode's attributes
721 * @lower_ia: Address of the lower inode's attributes
722 *
723 * Function to handle truncations modifying the size of the file. Note
724 * that the file sizes are interpolated. When expanding, we are simply
725 * writing strings of 0's out. When truncating, we truncate the upper
726 * inode and update the lower_ia according to the page index
727 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
728 * the caller must use lower_ia in a call to notify_change() to perform
729 * the truncation of the lower inode.
730 *
731 * Returns zero on success; non-zero otherwise
732 */
truncate_upper(struct dentry * dentry,struct iattr * ia,struct iattr * lower_ia)733 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
734 struct iattr *lower_ia)
735 {
736 int rc = 0;
737 struct inode *inode = d_inode(dentry);
738 struct ecryptfs_crypt_stat *crypt_stat;
739 loff_t i_size = i_size_read(inode);
740 loff_t lower_size_before_truncate;
741 loff_t lower_size_after_truncate;
742
743 if (unlikely((ia->ia_size == i_size))) {
744 lower_ia->ia_valid &= ~ATTR_SIZE;
745 return 0;
746 }
747 rc = ecryptfs_get_lower_file(dentry, inode);
748 if (rc)
749 return rc;
750 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
751 /* Switch on growing or shrinking file */
752 if (ia->ia_size > i_size) {
753 char zero[] = { 0x00 };
754
755 lower_ia->ia_valid &= ~ATTR_SIZE;
756 /* Write a single 0 at the last position of the file;
757 * this triggers code that will fill in 0's throughout
758 * the intermediate portion of the previous end of the
759 * file and the new and of the file */
760 rc = ecryptfs_write(inode, zero,
761 (ia->ia_size - 1), 1);
762 } else { /* ia->ia_size < i_size_read(inode) */
763 /* We're chopping off all the pages down to the page
764 * in which ia->ia_size is located. Fill in the end of
765 * that page from (ia->ia_size & ~PAGE_MASK) to
766 * PAGE_SIZE with zeros. */
767 size_t num_zeros = (PAGE_SIZE
768 - (ia->ia_size & ~PAGE_MASK));
769
770 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
771 truncate_setsize(inode, ia->ia_size);
772 lower_ia->ia_size = ia->ia_size;
773 lower_ia->ia_valid |= ATTR_SIZE;
774 goto out;
775 }
776 if (num_zeros) {
777 char *zeros_virt;
778
779 zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
780 if (!zeros_virt) {
781 rc = -ENOMEM;
782 goto out;
783 }
784 rc = ecryptfs_write(inode, zeros_virt,
785 ia->ia_size, num_zeros);
786 kfree(zeros_virt);
787 if (rc) {
788 printk(KERN_ERR "Error attempting to zero out "
789 "the remainder of the end page on "
790 "reducing truncate; rc = [%d]\n", rc);
791 goto out;
792 }
793 }
794 truncate_setsize(inode, ia->ia_size);
795 rc = ecryptfs_write_inode_size_to_metadata(inode);
796 if (rc) {
797 printk(KERN_ERR "Problem with "
798 "ecryptfs_write_inode_size_to_metadata; "
799 "rc = [%d]\n", rc);
800 goto out;
801 }
802 /* We are reducing the size of the ecryptfs file, and need to
803 * know if we need to reduce the size of the lower file. */
804 lower_size_before_truncate =
805 upper_size_to_lower_size(crypt_stat, i_size);
806 lower_size_after_truncate =
807 upper_size_to_lower_size(crypt_stat, ia->ia_size);
808 if (lower_size_after_truncate < lower_size_before_truncate) {
809 lower_ia->ia_size = lower_size_after_truncate;
810 lower_ia->ia_valid |= ATTR_SIZE;
811 } else
812 lower_ia->ia_valid &= ~ATTR_SIZE;
813 }
814 out:
815 ecryptfs_put_lower_file(inode);
816 return rc;
817 }
818
ecryptfs_inode_newsize_ok(struct inode * inode,loff_t offset)819 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
820 {
821 struct ecryptfs_crypt_stat *crypt_stat;
822 loff_t lower_oldsize, lower_newsize;
823
824 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
825 lower_oldsize = upper_size_to_lower_size(crypt_stat,
826 i_size_read(inode));
827 lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
828 if (lower_newsize > lower_oldsize) {
829 /*
830 * The eCryptfs inode and the new *lower* size are mixed here
831 * because we may not have the lower i_mutex held and/or it may
832 * not be appropriate to call inode_newsize_ok() with inodes
833 * from other filesystems.
834 */
835 return inode_newsize_ok(inode, lower_newsize);
836 }
837
838 return 0;
839 }
840
841 /**
842 * ecryptfs_truncate
843 * @dentry: The ecryptfs layer dentry
844 * @new_length: The length to expand the file to
845 *
846 * Simple function that handles the truncation of an eCryptfs inode and
847 * its corresponding lower inode.
848 *
849 * Returns zero on success; non-zero otherwise
850 */
ecryptfs_truncate(struct dentry * dentry,loff_t new_length)851 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
852 {
853 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
854 struct iattr lower_ia = { .ia_valid = 0 };
855 int rc;
856
857 rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
858 if (rc)
859 return rc;
860
861 rc = truncate_upper(dentry, &ia, &lower_ia);
862 if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
863 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
864
865 inode_lock(d_inode(lower_dentry));
866 rc = notify_change(lower_dentry, &lower_ia, NULL);
867 inode_unlock(d_inode(lower_dentry));
868 }
869 return rc;
870 }
871
872 static int
ecryptfs_permission(struct inode * inode,int mask)873 ecryptfs_permission(struct inode *inode, int mask)
874 {
875 return inode_permission(ecryptfs_inode_to_lower(inode), mask);
876 }
877
878 /**
879 * ecryptfs_setattr
880 * @dentry: dentry handle to the inode to modify
881 * @ia: Structure with flags of what to change and values
882 *
883 * Updates the metadata of an inode. If the update is to the size
884 * i.e. truncation, then ecryptfs_truncate will handle the size modification
885 * of both the ecryptfs inode and the lower inode.
886 *
887 * All other metadata changes will be passed right to the lower filesystem,
888 * and we will just update our inode to look like the lower.
889 */
ecryptfs_setattr(struct dentry * dentry,struct iattr * ia)890 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
891 {
892 int rc = 0;
893 struct dentry *lower_dentry;
894 struct iattr lower_ia;
895 struct inode *inode;
896 struct inode *lower_inode;
897 struct ecryptfs_crypt_stat *crypt_stat;
898
899 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
900 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
901 rc = ecryptfs_init_crypt_stat(crypt_stat);
902 if (rc)
903 return rc;
904 }
905 inode = d_inode(dentry);
906 lower_inode = ecryptfs_inode_to_lower(inode);
907 lower_dentry = ecryptfs_dentry_to_lower(dentry);
908 mutex_lock(&crypt_stat->cs_mutex);
909 if (d_is_dir(dentry))
910 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
911 else if (d_is_reg(dentry)
912 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
913 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
914 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
915
916 mount_crypt_stat = &ecryptfs_superblock_to_private(
917 dentry->d_sb)->mount_crypt_stat;
918 rc = ecryptfs_get_lower_file(dentry, inode);
919 if (rc) {
920 mutex_unlock(&crypt_stat->cs_mutex);
921 goto out;
922 }
923 rc = ecryptfs_read_metadata(dentry);
924 ecryptfs_put_lower_file(inode);
925 if (rc) {
926 if (!(mount_crypt_stat->flags
927 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
928 rc = -EIO;
929 printk(KERN_WARNING "Either the lower file "
930 "is not in a valid eCryptfs format, "
931 "or the key could not be retrieved. "
932 "Plaintext passthrough mode is not "
933 "enabled; returning -EIO\n");
934 mutex_unlock(&crypt_stat->cs_mutex);
935 goto out;
936 }
937 rc = 0;
938 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
939 | ECRYPTFS_ENCRYPTED);
940 }
941 }
942 mutex_unlock(&crypt_stat->cs_mutex);
943
944 rc = setattr_prepare(dentry, ia);
945 if (rc)
946 goto out;
947 if (ia->ia_valid & ATTR_SIZE) {
948 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
949 if (rc)
950 goto out;
951 }
952
953 memcpy(&lower_ia, ia, sizeof(lower_ia));
954 if (ia->ia_valid & ATTR_FILE)
955 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
956 if (ia->ia_valid & ATTR_SIZE) {
957 rc = truncate_upper(dentry, ia, &lower_ia);
958 if (rc < 0)
959 goto out;
960 }
961
962 /*
963 * mode change is for clearing setuid/setgid bits. Allow lower fs
964 * to interpret this in its own way.
965 */
966 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
967 lower_ia.ia_valid &= ~ATTR_MODE;
968
969 inode_lock(d_inode(lower_dentry));
970 rc = notify_change(lower_dentry, &lower_ia, NULL);
971 inode_unlock(d_inode(lower_dentry));
972 out:
973 fsstack_copy_attr_all(inode, lower_inode);
974 return rc;
975 }
976
ecryptfs_getattr_link(const struct path * path,struct kstat * stat,u32 request_mask,unsigned int flags)977 static int ecryptfs_getattr_link(const struct path *path, struct kstat *stat,
978 u32 request_mask, unsigned int flags)
979 {
980 struct dentry *dentry = path->dentry;
981 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
982 int rc = 0;
983
984 mount_crypt_stat = &ecryptfs_superblock_to_private(
985 dentry->d_sb)->mount_crypt_stat;
986 generic_fillattr(d_inode(dentry), stat);
987 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
988 char *target;
989 size_t targetsiz;
990
991 target = ecryptfs_readlink_lower(dentry, &targetsiz);
992 if (!IS_ERR(target)) {
993 kfree(target);
994 stat->size = targetsiz;
995 } else {
996 rc = PTR_ERR(target);
997 }
998 }
999 return rc;
1000 }
1001
ecryptfs_getattr(const struct path * path,struct kstat * stat,u32 request_mask,unsigned int flags)1002 static int ecryptfs_getattr(const struct path *path, struct kstat *stat,
1003 u32 request_mask, unsigned int flags)
1004 {
1005 struct dentry *dentry = path->dentry;
1006 struct kstat lower_stat;
1007 int rc;
1008
1009 rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
1010 request_mask, flags);
1011 if (!rc) {
1012 fsstack_copy_attr_all(d_inode(dentry),
1013 ecryptfs_inode_to_lower(d_inode(dentry)));
1014 generic_fillattr(d_inode(dentry), stat);
1015 stat->blocks = lower_stat.blocks;
1016 }
1017 return rc;
1018 }
1019
1020 int
ecryptfs_setxattr(struct dentry * dentry,struct inode * inode,const char * name,const void * value,size_t size,int flags)1021 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1022 const char *name, const void *value,
1023 size_t size, int flags)
1024 {
1025 int rc;
1026 struct dentry *lower_dentry;
1027
1028 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1029 if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1030 rc = -EOPNOTSUPP;
1031 goto out;
1032 }
1033 rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1034 if (!rc && inode)
1035 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1036 out:
1037 return rc;
1038 }
1039
1040 ssize_t
ecryptfs_getxattr_lower(struct dentry * lower_dentry,struct inode * lower_inode,const char * name,void * value,size_t size)1041 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1042 const char *name, void *value, size_t size)
1043 {
1044 int rc;
1045
1046 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1047 rc = -EOPNOTSUPP;
1048 goto out;
1049 }
1050 inode_lock(lower_inode);
1051 rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size,
1052 XATTR_NOSECURITY);
1053 inode_unlock(lower_inode);
1054 out:
1055 return rc;
1056 }
1057
1058 static ssize_t
ecryptfs_getxattr(struct dentry * dentry,struct inode * inode,const char * name,void * value,size_t size)1059 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1060 const char *name, void *value, size_t size)
1061 {
1062 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1063 ecryptfs_inode_to_lower(inode),
1064 name, value, size);
1065 }
1066
1067 static ssize_t
ecryptfs_listxattr(struct dentry * dentry,char * list,size_t size)1068 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1069 {
1070 int rc = 0;
1071 struct dentry *lower_dentry;
1072
1073 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1074 if (!d_inode(lower_dentry)->i_op->listxattr) {
1075 rc = -EOPNOTSUPP;
1076 goto out;
1077 }
1078 inode_lock(d_inode(lower_dentry));
1079 rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1080 inode_unlock(d_inode(lower_dentry));
1081 out:
1082 return rc;
1083 }
1084
ecryptfs_removexattr(struct dentry * dentry,struct inode * inode,const char * name)1085 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1086 const char *name)
1087 {
1088 int rc;
1089 struct dentry *lower_dentry;
1090 struct inode *lower_inode;
1091
1092 lower_dentry = ecryptfs_dentry_to_lower(dentry);
1093 lower_inode = ecryptfs_inode_to_lower(inode);
1094 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1095 rc = -EOPNOTSUPP;
1096 goto out;
1097 }
1098 inode_lock(lower_inode);
1099 rc = __vfs_removexattr(lower_dentry, name);
1100 inode_unlock(lower_inode);
1101 out:
1102 return rc;
1103 }
1104
1105 const struct inode_operations ecryptfs_symlink_iops = {
1106 .get_link = ecryptfs_get_link,
1107 .permission = ecryptfs_permission,
1108 .setattr = ecryptfs_setattr,
1109 .getattr = ecryptfs_getattr_link,
1110 .listxattr = ecryptfs_listxattr,
1111 };
1112
1113 const struct inode_operations ecryptfs_dir_iops = {
1114 .create = ecryptfs_create,
1115 .lookup = ecryptfs_lookup,
1116 .link = ecryptfs_link,
1117 .unlink = ecryptfs_unlink,
1118 .symlink = ecryptfs_symlink,
1119 .mkdir = ecryptfs_mkdir,
1120 .rmdir = ecryptfs_rmdir,
1121 .mknod = ecryptfs_mknod,
1122 .rename = ecryptfs_rename,
1123 .permission = ecryptfs_permission,
1124 .setattr = ecryptfs_setattr,
1125 .listxattr = ecryptfs_listxattr,
1126 };
1127
1128 const struct inode_operations ecryptfs_main_iops = {
1129 .permission = ecryptfs_permission,
1130 .setattr = ecryptfs_setattr,
1131 .getattr = ecryptfs_getattr,
1132 .listxattr = ecryptfs_listxattr,
1133 };
1134
ecryptfs_xattr_get(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,void * buffer,size_t size,int flags)1135 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1136 struct dentry *dentry, struct inode *inode,
1137 const char *name, void *buffer, size_t size,
1138 int flags)
1139 {
1140 return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1141 }
1142
ecryptfs_xattr_set(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,const void * value,size_t size,int flags)1143 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1144 struct dentry *dentry, struct inode *inode,
1145 const char *name, const void *value, size_t size,
1146 int flags)
1147 {
1148 if (value)
1149 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1150 else {
1151 BUG_ON(flags != XATTR_REPLACE);
1152 return ecryptfs_removexattr(dentry, inode, name);
1153 }
1154 }
1155
1156 static const struct xattr_handler ecryptfs_xattr_handler = {
1157 .prefix = "", /* match anything */
1158 .get = ecryptfs_xattr_get,
1159 .set = ecryptfs_xattr_set,
1160 };
1161
1162 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1163 &ecryptfs_xattr_handler,
1164 NULL
1165 };
1166