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