1 /**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2003 Erez Zadok
5 * Copyright (C) 2001-2003 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. Thompson <mcthomps@us.ibm.com>
9 * Tyler Hicks <tyhicks@ou.edu>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License as
13 * published by the Free Software Foundation; either version 2 of the
14 * License, or (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
24 * 02111-1307, USA.
25 */
26
27 #include <linux/dcache.h>
28 #include <linux/file.h>
29 #include <linux/module.h>
30 #include <linux/namei.h>
31 #include <linux/skbuff.h>
32 #include <linux/crypto.h>
33 #include <linux/mount.h>
34 #include <linux/pagemap.h>
35 #include <linux/key.h>
36 #include <linux/parser.h>
37 #include <linux/fs_stack.h>
38 #include <linux/slab.h>
39 #include <linux/magic.h>
40 #include "ecryptfs_kernel.h"
41
42 /**
43 * Module parameter that defines the ecryptfs_verbosity level.
44 */
45 int ecryptfs_verbosity = 0;
46
47 module_param(ecryptfs_verbosity, int, 0);
48 MODULE_PARM_DESC(ecryptfs_verbosity,
49 "Initial verbosity level (0 or 1; defaults to "
50 "0, which is Quiet)");
51
52 /**
53 * Module parameter that defines the number of message buffer elements
54 */
55 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
56
57 module_param(ecryptfs_message_buf_len, uint, 0);
58 MODULE_PARM_DESC(ecryptfs_message_buf_len,
59 "Number of message buffer elements");
60
61 /**
62 * Module parameter that defines the maximum guaranteed amount of time to wait
63 * for a response from ecryptfsd. The actual sleep time will be, more than
64 * likely, a small amount greater than this specified value, but only less if
65 * the message successfully arrives.
66 */
67 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
68
69 module_param(ecryptfs_message_wait_timeout, long, 0);
70 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
71 "Maximum number of seconds that an operation will "
72 "sleep while waiting for a message response from "
73 "userspace");
74
75 /**
76 * Module parameter that is an estimate of the maximum number of users
77 * that will be concurrently using eCryptfs. Set this to the right
78 * value to balance performance and memory use.
79 */
80 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
81
82 module_param(ecryptfs_number_of_users, uint, 0);
83 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
84 "concurrent users of eCryptfs");
85
__ecryptfs_printk(const char * fmt,...)86 void __ecryptfs_printk(const char *fmt, ...)
87 {
88 va_list args;
89 va_start(args, fmt);
90 if (fmt[1] == '7') { /* KERN_DEBUG */
91 if (ecryptfs_verbosity >= 1)
92 vprintk(fmt, args);
93 } else
94 vprintk(fmt, args);
95 va_end(args);
96 }
97
98 /**
99 * ecryptfs_init_lower_file
100 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
101 * the lower dentry and the lower mount set
102 *
103 * eCryptfs only ever keeps a single open file for every lower
104 * inode. All I/O operations to the lower inode occur through that
105 * file. When the first eCryptfs dentry that interposes with the first
106 * lower dentry for that inode is created, this function creates the
107 * lower file struct and associates it with the eCryptfs
108 * inode. When all eCryptfs files associated with the inode are released, the
109 * file is closed.
110 *
111 * The lower file will be opened with read/write permissions, if
112 * possible. Otherwise, it is opened read-only.
113 *
114 * This function does nothing if a lower file is already
115 * associated with the eCryptfs inode.
116 *
117 * Returns zero on success; non-zero otherwise
118 */
ecryptfs_init_lower_file(struct dentry * dentry,struct file ** lower_file)119 static int ecryptfs_init_lower_file(struct dentry *dentry,
120 struct file **lower_file)
121 {
122 const struct cred *cred = current_cred();
123 struct path *path = ecryptfs_dentry_to_lower_path(dentry);
124 int rc;
125
126 rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
127 cred);
128 if (rc) {
129 printk(KERN_ERR "Error opening lower file "
130 "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
131 "rc = [%d]\n", path->dentry, path->mnt, rc);
132 (*lower_file) = NULL;
133 }
134 return rc;
135 }
136
ecryptfs_get_lower_file(struct dentry * dentry,struct inode * inode)137 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
138 {
139 struct ecryptfs_inode_info *inode_info;
140 int count, rc = 0;
141
142 inode_info = ecryptfs_inode_to_private(inode);
143 mutex_lock(&inode_info->lower_file_mutex);
144 count = atomic_inc_return(&inode_info->lower_file_count);
145 if (WARN_ON_ONCE(count < 1))
146 rc = -EINVAL;
147 else if (count == 1) {
148 rc = ecryptfs_init_lower_file(dentry,
149 &inode_info->lower_file);
150 if (rc)
151 atomic_set(&inode_info->lower_file_count, 0);
152 }
153 mutex_unlock(&inode_info->lower_file_mutex);
154 return rc;
155 }
156
ecryptfs_put_lower_file(struct inode * inode)157 void ecryptfs_put_lower_file(struct inode *inode)
158 {
159 struct ecryptfs_inode_info *inode_info;
160
161 inode_info = ecryptfs_inode_to_private(inode);
162 if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
163 &inode_info->lower_file_mutex)) {
164 filemap_write_and_wait(inode->i_mapping);
165 fput(inode_info->lower_file);
166 inode_info->lower_file = NULL;
167 mutex_unlock(&inode_info->lower_file_mutex);
168 }
169 }
170
171 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
172 ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
173 ecryptfs_opt_ecryptfs_key_bytes,
174 ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
175 ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
176 ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
177 ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
178 ecryptfs_opt_check_dev_ruid,
179 ecryptfs_opt_err };
180
181 static const match_table_t tokens = {
182 {ecryptfs_opt_sig, "sig=%s"},
183 {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
184 {ecryptfs_opt_cipher, "cipher=%s"},
185 {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
186 {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
187 {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
188 {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
189 {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
190 {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
191 {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
192 {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
193 {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
194 {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
195 {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
196 {ecryptfs_opt_err, NULL}
197 };
198
ecryptfs_init_global_auth_toks(struct ecryptfs_mount_crypt_stat * mount_crypt_stat)199 static int ecryptfs_init_global_auth_toks(
200 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
201 {
202 struct ecryptfs_global_auth_tok *global_auth_tok;
203 struct ecryptfs_auth_tok *auth_tok;
204 int rc = 0;
205
206 list_for_each_entry(global_auth_tok,
207 &mount_crypt_stat->global_auth_tok_list,
208 mount_crypt_stat_list) {
209 rc = ecryptfs_keyring_auth_tok_for_sig(
210 &global_auth_tok->global_auth_tok_key, &auth_tok,
211 global_auth_tok->sig);
212 if (rc) {
213 printk(KERN_ERR "Could not find valid key in user "
214 "session keyring for sig specified in mount "
215 "option: [%s]\n", global_auth_tok->sig);
216 global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
217 goto out;
218 } else {
219 global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
220 up_write(&(global_auth_tok->global_auth_tok_key)->sem);
221 }
222 }
223 out:
224 return rc;
225 }
226
ecryptfs_init_mount_crypt_stat(struct ecryptfs_mount_crypt_stat * mount_crypt_stat)227 static void ecryptfs_init_mount_crypt_stat(
228 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
229 {
230 memset((void *)mount_crypt_stat, 0,
231 sizeof(struct ecryptfs_mount_crypt_stat));
232 INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
233 mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
234 mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
235 }
236
237 /**
238 * ecryptfs_parse_options
239 * @sb: The ecryptfs super block
240 * @options: The options passed to the kernel
241 * @check_ruid: set to 1 if device uid should be checked against the ruid
242 *
243 * Parse mount options:
244 * debug=N - ecryptfs_verbosity level for debug output
245 * sig=XXX - description(signature) of the key to use
246 *
247 * Returns the dentry object of the lower-level (lower/interposed)
248 * directory; We want to mount our stackable file system on top of
249 * that lower directory.
250 *
251 * The signature of the key to use must be the description of a key
252 * already in the keyring. Mounting will fail if the key can not be
253 * found.
254 *
255 * Returns zero on success; non-zero on error
256 */
ecryptfs_parse_options(struct ecryptfs_sb_info * sbi,char * options,uid_t * check_ruid)257 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
258 uid_t *check_ruid)
259 {
260 char *p;
261 int rc = 0;
262 int sig_set = 0;
263 int cipher_name_set = 0;
264 int fn_cipher_name_set = 0;
265 int cipher_key_bytes;
266 int cipher_key_bytes_set = 0;
267 int fn_cipher_key_bytes;
268 int fn_cipher_key_bytes_set = 0;
269 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
270 &sbi->mount_crypt_stat;
271 substring_t args[MAX_OPT_ARGS];
272 int token;
273 char *sig_src;
274 char *cipher_name_dst;
275 char *cipher_name_src;
276 char *fn_cipher_name_dst;
277 char *fn_cipher_name_src;
278 char *fnek_dst;
279 char *fnek_src;
280 char *cipher_key_bytes_src;
281 char *fn_cipher_key_bytes_src;
282 u8 cipher_code;
283
284 *check_ruid = 0;
285
286 if (!options) {
287 rc = -EINVAL;
288 goto out;
289 }
290 ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
291 while ((p = strsep(&options, ",")) != NULL) {
292 if (!*p)
293 continue;
294 token = match_token(p, tokens, args);
295 switch (token) {
296 case ecryptfs_opt_sig:
297 case ecryptfs_opt_ecryptfs_sig:
298 sig_src = args[0].from;
299 rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
300 sig_src, 0);
301 if (rc) {
302 printk(KERN_ERR "Error attempting to register "
303 "global sig; rc = [%d]\n", rc);
304 goto out;
305 }
306 sig_set = 1;
307 break;
308 case ecryptfs_opt_cipher:
309 case ecryptfs_opt_ecryptfs_cipher:
310 cipher_name_src = args[0].from;
311 cipher_name_dst =
312 mount_crypt_stat->
313 global_default_cipher_name;
314 strncpy(cipher_name_dst, cipher_name_src,
315 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
316 cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
317 cipher_name_set = 1;
318 break;
319 case ecryptfs_opt_ecryptfs_key_bytes:
320 cipher_key_bytes_src = args[0].from;
321 cipher_key_bytes =
322 (int)simple_strtol(cipher_key_bytes_src,
323 &cipher_key_bytes_src, 0);
324 mount_crypt_stat->global_default_cipher_key_size =
325 cipher_key_bytes;
326 cipher_key_bytes_set = 1;
327 break;
328 case ecryptfs_opt_passthrough:
329 mount_crypt_stat->flags |=
330 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
331 break;
332 case ecryptfs_opt_xattr_metadata:
333 mount_crypt_stat->flags |=
334 ECRYPTFS_XATTR_METADATA_ENABLED;
335 break;
336 case ecryptfs_opt_encrypted_view:
337 mount_crypt_stat->flags |=
338 ECRYPTFS_XATTR_METADATA_ENABLED;
339 mount_crypt_stat->flags |=
340 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
341 break;
342 case ecryptfs_opt_fnek_sig:
343 fnek_src = args[0].from;
344 fnek_dst =
345 mount_crypt_stat->global_default_fnek_sig;
346 strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
347 mount_crypt_stat->global_default_fnek_sig[
348 ECRYPTFS_SIG_SIZE_HEX] = '\0';
349 rc = ecryptfs_add_global_auth_tok(
350 mount_crypt_stat,
351 mount_crypt_stat->global_default_fnek_sig,
352 ECRYPTFS_AUTH_TOK_FNEK);
353 if (rc) {
354 printk(KERN_ERR "Error attempting to register "
355 "global fnek sig [%s]; rc = [%d]\n",
356 mount_crypt_stat->global_default_fnek_sig,
357 rc);
358 goto out;
359 }
360 mount_crypt_stat->flags |=
361 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
362 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
363 break;
364 case ecryptfs_opt_fn_cipher:
365 fn_cipher_name_src = args[0].from;
366 fn_cipher_name_dst =
367 mount_crypt_stat->global_default_fn_cipher_name;
368 strncpy(fn_cipher_name_dst, fn_cipher_name_src,
369 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
370 mount_crypt_stat->global_default_fn_cipher_name[
371 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
372 fn_cipher_name_set = 1;
373 break;
374 case ecryptfs_opt_fn_cipher_key_bytes:
375 fn_cipher_key_bytes_src = args[0].from;
376 fn_cipher_key_bytes =
377 (int)simple_strtol(fn_cipher_key_bytes_src,
378 &fn_cipher_key_bytes_src, 0);
379 mount_crypt_stat->global_default_fn_cipher_key_bytes =
380 fn_cipher_key_bytes;
381 fn_cipher_key_bytes_set = 1;
382 break;
383 case ecryptfs_opt_unlink_sigs:
384 mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
385 break;
386 case ecryptfs_opt_mount_auth_tok_only:
387 mount_crypt_stat->flags |=
388 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
389 break;
390 case ecryptfs_opt_check_dev_ruid:
391 *check_ruid = 1;
392 break;
393 case ecryptfs_opt_err:
394 default:
395 printk(KERN_WARNING
396 "%s: eCryptfs: unrecognized option [%s]\n",
397 __func__, p);
398 }
399 }
400 if (!sig_set) {
401 rc = -EINVAL;
402 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
403 "auth tok signature as a mount "
404 "parameter; see the eCryptfs README\n");
405 goto out;
406 }
407 if (!cipher_name_set) {
408 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
409
410 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
411 strcpy(mount_crypt_stat->global_default_cipher_name,
412 ECRYPTFS_DEFAULT_CIPHER);
413 }
414 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
415 && !fn_cipher_name_set)
416 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
417 mount_crypt_stat->global_default_cipher_name);
418 if (!cipher_key_bytes_set)
419 mount_crypt_stat->global_default_cipher_key_size = 0;
420 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
421 && !fn_cipher_key_bytes_set)
422 mount_crypt_stat->global_default_fn_cipher_key_bytes =
423 mount_crypt_stat->global_default_cipher_key_size;
424
425 cipher_code = ecryptfs_code_for_cipher_string(
426 mount_crypt_stat->global_default_cipher_name,
427 mount_crypt_stat->global_default_cipher_key_size);
428 if (!cipher_code) {
429 ecryptfs_printk(KERN_ERR,
430 "eCryptfs doesn't support cipher: %s",
431 mount_crypt_stat->global_default_cipher_name);
432 rc = -EINVAL;
433 goto out;
434 }
435
436 mutex_lock(&key_tfm_list_mutex);
437 if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
438 NULL)) {
439 rc = ecryptfs_add_new_key_tfm(
440 NULL, mount_crypt_stat->global_default_cipher_name,
441 mount_crypt_stat->global_default_cipher_key_size);
442 if (rc) {
443 printk(KERN_ERR "Error attempting to initialize "
444 "cipher with name = [%s] and key size = [%td]; "
445 "rc = [%d]\n",
446 mount_crypt_stat->global_default_cipher_name,
447 mount_crypt_stat->global_default_cipher_key_size,
448 rc);
449 rc = -EINVAL;
450 mutex_unlock(&key_tfm_list_mutex);
451 goto out;
452 }
453 }
454 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
455 && !ecryptfs_tfm_exists(
456 mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
457 rc = ecryptfs_add_new_key_tfm(
458 NULL, mount_crypt_stat->global_default_fn_cipher_name,
459 mount_crypt_stat->global_default_fn_cipher_key_bytes);
460 if (rc) {
461 printk(KERN_ERR "Error attempting to initialize "
462 "cipher with name = [%s] and key size = [%td]; "
463 "rc = [%d]\n",
464 mount_crypt_stat->global_default_fn_cipher_name,
465 mount_crypt_stat->global_default_fn_cipher_key_bytes,
466 rc);
467 rc = -EINVAL;
468 mutex_unlock(&key_tfm_list_mutex);
469 goto out;
470 }
471 }
472 mutex_unlock(&key_tfm_list_mutex);
473 rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
474 if (rc)
475 printk(KERN_WARNING "One or more global auth toks could not "
476 "properly register; rc = [%d]\n", rc);
477 out:
478 return rc;
479 }
480
481 struct kmem_cache *ecryptfs_sb_info_cache;
482 static struct file_system_type ecryptfs_fs_type;
483
484 /**
485 * ecryptfs_get_sb
486 * @fs_type
487 * @flags
488 * @dev_name: The path to mount over
489 * @raw_data: The options passed into the kernel
490 */
ecryptfs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * raw_data)491 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
492 const char *dev_name, void *raw_data)
493 {
494 struct super_block *s;
495 struct ecryptfs_sb_info *sbi;
496 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
497 struct ecryptfs_dentry_info *root_info;
498 const char *err = "Getting sb failed";
499 struct inode *inode;
500 struct path path;
501 uid_t check_ruid;
502 int rc;
503
504 sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
505 if (!sbi) {
506 rc = -ENOMEM;
507 goto out;
508 }
509
510 if (!dev_name) {
511 rc = -EINVAL;
512 err = "Device name cannot be null";
513 goto out;
514 }
515
516 rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
517 if (rc) {
518 err = "Error parsing options";
519 goto out;
520 }
521 mount_crypt_stat = &sbi->mount_crypt_stat;
522
523 s = sget(fs_type, NULL, set_anon_super, flags, NULL);
524 if (IS_ERR(s)) {
525 rc = PTR_ERR(s);
526 goto out;
527 }
528
529 rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs");
530 if (rc)
531 goto out1;
532
533 ecryptfs_set_superblock_private(s, sbi);
534 s->s_bdi = &sbi->bdi;
535
536 /* ->kill_sb() will take care of sbi after that point */
537 sbi = NULL;
538 s->s_op = &ecryptfs_sops;
539 s->s_d_op = &ecryptfs_dops;
540
541 err = "Reading sb failed";
542 rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
543 if (rc) {
544 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
545 goto out1;
546 }
547 if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
548 rc = -EINVAL;
549 printk(KERN_ERR "Mount on filesystem of type "
550 "eCryptfs explicitly disallowed due to "
551 "known incompatibilities\n");
552 goto out_free;
553 }
554
555 if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
556 rc = -EPERM;
557 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
558 "requested user (uid: %d)\n",
559 i_uid_read(d_inode(path.dentry)),
560 from_kuid(&init_user_ns, current_uid()));
561 goto out_free;
562 }
563
564 ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
565
566 /**
567 * Set the POSIX ACL flag based on whether they're enabled in the lower
568 * mount.
569 */
570 s->s_flags = flags & ~MS_POSIXACL;
571 s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL;
572
573 /**
574 * Force a read-only eCryptfs mount when:
575 * 1) The lower mount is ro
576 * 2) The ecryptfs_encrypted_view mount option is specified
577 */
578 if (path.dentry->d_sb->s_flags & MS_RDONLY ||
579 mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
580 s->s_flags |= MS_RDONLY;
581
582 s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
583 s->s_blocksize = path.dentry->d_sb->s_blocksize;
584 s->s_magic = ECRYPTFS_SUPER_MAGIC;
585 s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
586
587 rc = -EINVAL;
588 if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
589 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
590 goto out_free;
591 }
592
593 inode = ecryptfs_get_inode(d_inode(path.dentry), s);
594 rc = PTR_ERR(inode);
595 if (IS_ERR(inode))
596 goto out_free;
597
598 s->s_root = d_make_root(inode);
599 if (!s->s_root) {
600 rc = -ENOMEM;
601 goto out_free;
602 }
603
604 rc = -ENOMEM;
605 root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
606 if (!root_info)
607 goto out_free;
608
609 /* ->kill_sb() will take care of root_info */
610 ecryptfs_set_dentry_private(s->s_root, root_info);
611 root_info->lower_path = path;
612
613 s->s_flags |= MS_ACTIVE;
614 return dget(s->s_root);
615
616 out_free:
617 path_put(&path);
618 out1:
619 deactivate_locked_super(s);
620 out:
621 if (sbi) {
622 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
623 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
624 }
625 printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
626 return ERR_PTR(rc);
627 }
628
629 /**
630 * ecryptfs_kill_block_super
631 * @sb: The ecryptfs super block
632 *
633 * Used to bring the superblock down and free the private data.
634 */
ecryptfs_kill_block_super(struct super_block * sb)635 static void ecryptfs_kill_block_super(struct super_block *sb)
636 {
637 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
638 kill_anon_super(sb);
639 if (!sb_info)
640 return;
641 ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
642 bdi_destroy(&sb_info->bdi);
643 kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
644 }
645
646 static struct file_system_type ecryptfs_fs_type = {
647 .owner = THIS_MODULE,
648 .name = "ecryptfs",
649 .mount = ecryptfs_mount,
650 .kill_sb = ecryptfs_kill_block_super,
651 .fs_flags = 0
652 };
653 MODULE_ALIAS_FS("ecryptfs");
654
655 /**
656 * inode_info_init_once
657 *
658 * Initializes the ecryptfs_inode_info_cache when it is created
659 */
660 static void
inode_info_init_once(void * vptr)661 inode_info_init_once(void *vptr)
662 {
663 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
664
665 inode_init_once(&ei->vfs_inode);
666 }
667
668 static struct ecryptfs_cache_info {
669 struct kmem_cache **cache;
670 const char *name;
671 size_t size;
672 void (*ctor)(void *obj);
673 } ecryptfs_cache_infos[] = {
674 {
675 .cache = &ecryptfs_auth_tok_list_item_cache,
676 .name = "ecryptfs_auth_tok_list_item",
677 .size = sizeof(struct ecryptfs_auth_tok_list_item),
678 },
679 {
680 .cache = &ecryptfs_file_info_cache,
681 .name = "ecryptfs_file_cache",
682 .size = sizeof(struct ecryptfs_file_info),
683 },
684 {
685 .cache = &ecryptfs_dentry_info_cache,
686 .name = "ecryptfs_dentry_info_cache",
687 .size = sizeof(struct ecryptfs_dentry_info),
688 },
689 {
690 .cache = &ecryptfs_inode_info_cache,
691 .name = "ecryptfs_inode_cache",
692 .size = sizeof(struct ecryptfs_inode_info),
693 .ctor = inode_info_init_once,
694 },
695 {
696 .cache = &ecryptfs_sb_info_cache,
697 .name = "ecryptfs_sb_cache",
698 .size = sizeof(struct ecryptfs_sb_info),
699 },
700 {
701 .cache = &ecryptfs_header_cache,
702 .name = "ecryptfs_headers",
703 .size = PAGE_CACHE_SIZE,
704 },
705 {
706 .cache = &ecryptfs_xattr_cache,
707 .name = "ecryptfs_xattr_cache",
708 .size = PAGE_CACHE_SIZE,
709 },
710 {
711 .cache = &ecryptfs_key_record_cache,
712 .name = "ecryptfs_key_record_cache",
713 .size = sizeof(struct ecryptfs_key_record),
714 },
715 {
716 .cache = &ecryptfs_key_sig_cache,
717 .name = "ecryptfs_key_sig_cache",
718 .size = sizeof(struct ecryptfs_key_sig),
719 },
720 {
721 .cache = &ecryptfs_global_auth_tok_cache,
722 .name = "ecryptfs_global_auth_tok_cache",
723 .size = sizeof(struct ecryptfs_global_auth_tok),
724 },
725 {
726 .cache = &ecryptfs_key_tfm_cache,
727 .name = "ecryptfs_key_tfm_cache",
728 .size = sizeof(struct ecryptfs_key_tfm),
729 },
730 };
731
ecryptfs_free_kmem_caches(void)732 static void ecryptfs_free_kmem_caches(void)
733 {
734 int i;
735
736 /*
737 * Make sure all delayed rcu free inodes are flushed before we
738 * destroy cache.
739 */
740 rcu_barrier();
741
742 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
743 struct ecryptfs_cache_info *info;
744
745 info = &ecryptfs_cache_infos[i];
746 if (*(info->cache))
747 kmem_cache_destroy(*(info->cache));
748 }
749 }
750
751 /**
752 * ecryptfs_init_kmem_caches
753 *
754 * Returns zero on success; non-zero otherwise
755 */
ecryptfs_init_kmem_caches(void)756 static int ecryptfs_init_kmem_caches(void)
757 {
758 int i;
759
760 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
761 struct ecryptfs_cache_info *info;
762
763 info = &ecryptfs_cache_infos[i];
764 *(info->cache) = kmem_cache_create(info->name, info->size,
765 0, SLAB_HWCACHE_ALIGN, info->ctor);
766 if (!*(info->cache)) {
767 ecryptfs_free_kmem_caches();
768 ecryptfs_printk(KERN_WARNING, "%s: "
769 "kmem_cache_create failed\n",
770 info->name);
771 return -ENOMEM;
772 }
773 }
774 return 0;
775 }
776
777 static struct kobject *ecryptfs_kobj;
778
version_show(struct kobject * kobj,struct kobj_attribute * attr,char * buff)779 static ssize_t version_show(struct kobject *kobj,
780 struct kobj_attribute *attr, char *buff)
781 {
782 return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
783 }
784
785 static struct kobj_attribute version_attr = __ATTR_RO(version);
786
787 static struct attribute *attributes[] = {
788 &version_attr.attr,
789 NULL,
790 };
791
792 static struct attribute_group attr_group = {
793 .attrs = attributes,
794 };
795
do_sysfs_registration(void)796 static int do_sysfs_registration(void)
797 {
798 int rc;
799
800 ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
801 if (!ecryptfs_kobj) {
802 printk(KERN_ERR "Unable to create ecryptfs kset\n");
803 rc = -ENOMEM;
804 goto out;
805 }
806 rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
807 if (rc) {
808 printk(KERN_ERR
809 "Unable to create ecryptfs version attributes\n");
810 kobject_put(ecryptfs_kobj);
811 }
812 out:
813 return rc;
814 }
815
do_sysfs_unregistration(void)816 static void do_sysfs_unregistration(void)
817 {
818 sysfs_remove_group(ecryptfs_kobj, &attr_group);
819 kobject_put(ecryptfs_kobj);
820 }
821
ecryptfs_init(void)822 static int __init ecryptfs_init(void)
823 {
824 int rc;
825
826 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
827 rc = -EINVAL;
828 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
829 "larger than the host's page size, and so "
830 "eCryptfs cannot run on this system. The "
831 "default eCryptfs extent size is [%u] bytes; "
832 "the page size is [%lu] bytes.\n",
833 ECRYPTFS_DEFAULT_EXTENT_SIZE,
834 (unsigned long)PAGE_CACHE_SIZE);
835 goto out;
836 }
837 rc = ecryptfs_init_kmem_caches();
838 if (rc) {
839 printk(KERN_ERR
840 "Failed to allocate one or more kmem_cache objects\n");
841 goto out;
842 }
843 rc = do_sysfs_registration();
844 if (rc) {
845 printk(KERN_ERR "sysfs registration failed\n");
846 goto out_free_kmem_caches;
847 }
848 rc = ecryptfs_init_kthread();
849 if (rc) {
850 printk(KERN_ERR "%s: kthread initialization failed; "
851 "rc = [%d]\n", __func__, rc);
852 goto out_do_sysfs_unregistration;
853 }
854 rc = ecryptfs_init_messaging();
855 if (rc) {
856 printk(KERN_ERR "Failure occurred while attempting to "
857 "initialize the communications channel to "
858 "ecryptfsd\n");
859 goto out_destroy_kthread;
860 }
861 rc = ecryptfs_init_crypto();
862 if (rc) {
863 printk(KERN_ERR "Failure whilst attempting to init crypto; "
864 "rc = [%d]\n", rc);
865 goto out_release_messaging;
866 }
867 rc = register_filesystem(&ecryptfs_fs_type);
868 if (rc) {
869 printk(KERN_ERR "Failed to register filesystem\n");
870 goto out_destroy_crypto;
871 }
872 if (ecryptfs_verbosity > 0)
873 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
874 "will be written to the syslog!\n", ecryptfs_verbosity);
875
876 goto out;
877 out_destroy_crypto:
878 ecryptfs_destroy_crypto();
879 out_release_messaging:
880 ecryptfs_release_messaging();
881 out_destroy_kthread:
882 ecryptfs_destroy_kthread();
883 out_do_sysfs_unregistration:
884 do_sysfs_unregistration();
885 out_free_kmem_caches:
886 ecryptfs_free_kmem_caches();
887 out:
888 return rc;
889 }
890
ecryptfs_exit(void)891 static void __exit ecryptfs_exit(void)
892 {
893 int rc;
894
895 rc = ecryptfs_destroy_crypto();
896 if (rc)
897 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
898 "rc = [%d]\n", rc);
899 ecryptfs_release_messaging();
900 ecryptfs_destroy_kthread();
901 do_sysfs_unregistration();
902 unregister_filesystem(&ecryptfs_fs_type);
903 ecryptfs_free_kmem_caches();
904 }
905
906 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
907 MODULE_DESCRIPTION("eCryptfs");
908
909 MODULE_LICENSE("GPL");
910
911 module_init(ecryptfs_init)
912 module_exit(ecryptfs_exit)
913