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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 */
44int ecryptfs_verbosity = 0;
45
46module_param(ecryptfs_verbosity, int, 0);
47MODULE_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 */
54unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
55
56module_param(ecryptfs_message_buf_len, uint, 0);
57MODULE_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 */
66signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
67
68module_param(ecryptfs_message_wait_timeout, long, 0);
69MODULE_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 */
79unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
80
81module_param(ecryptfs_number_of_users, uint, 0);
82MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
83 "concurrent users of eCryptfs");
84
85void __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 */
118static 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
136int 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
156void 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
170enum { 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
180static 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
198static 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 }
222out:
223 return rc;
224}
225
226static 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 */
256static 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",
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);
476out:
477 return rc;
478}
479
480struct kmem_cache *ecryptfs_sb_info_cache;
481static 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 */
490static 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 rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
510 if (rc) {
511 err = "Error parsing options";
512 goto out;
513 }
514 mount_crypt_stat = &sbi->mount_crypt_stat;
515
516 s = sget(fs_type, NULL, set_anon_super, flags, NULL);
517 if (IS_ERR(s)) {
518 rc = PTR_ERR(s);
519 goto out;
520 }
521
522 rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs");
523 if (rc)
524 goto out1;
525
526 ecryptfs_set_superblock_private(s, sbi);
527 s->s_bdi = &sbi->bdi;
528
529 /* ->kill_sb() will take care of sbi after that point */
530 sbi = NULL;
531 s->s_op = &ecryptfs_sops;
532 s->s_xattr = ecryptfs_xattr_handlers;
533 s->s_d_op = &ecryptfs_dops;
534
535 err = "Reading sb failed";
536 rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
537 if (rc) {
538 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
539 goto out1;
540 }
541 if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
542 rc = -EINVAL;
543 printk(KERN_ERR "Mount on filesystem of type "
544 "eCryptfs explicitly disallowed due to "
545 "known incompatibilities\n");
546 goto out_free;
547 }
548
549 if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
550 rc = -EPERM;
551 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
552 "requested user (uid: %d)\n",
553 i_uid_read(d_inode(path.dentry)),
554 from_kuid(&init_user_ns, current_uid()));
555 goto out_free;
556 }
557
558 ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
559
560 /**
561 * Set the POSIX ACL flag based on whether they're enabled in the lower
562 * mount.
563 */
564 s->s_flags = flags & ~MS_POSIXACL;
565 s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL;
566
567 /**
568 * Force a read-only eCryptfs mount when:
569 * 1) The lower mount is ro
570 * 2) The ecryptfs_encrypted_view mount option is specified
571 */
572 if (path.dentry->d_sb->s_flags & MS_RDONLY ||
573 mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
574 s->s_flags |= MS_RDONLY;
575
576 s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
577 s->s_blocksize = path.dentry->d_sb->s_blocksize;
578 s->s_magic = ECRYPTFS_SUPER_MAGIC;
579 s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
580
581 rc = -EINVAL;
582 if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
583 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
584 goto out_free;
585 }
586
587 inode = ecryptfs_get_inode(d_inode(path.dentry), s);
588 rc = PTR_ERR(inode);
589 if (IS_ERR(inode))
590 goto out_free;
591
592 s->s_root = d_make_root(inode);
593 if (!s->s_root) {
594 rc = -ENOMEM;
595 goto out_free;
596 }
597
598 rc = -ENOMEM;
599 root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
600 if (!root_info)
601 goto out_free;
602
603 /* ->kill_sb() will take care of root_info */
604 ecryptfs_set_dentry_private(s->s_root, root_info);
605 root_info->lower_path = path;
606
607 s->s_flags |= MS_ACTIVE;
608 return dget(s->s_root);
609
610out_free:
611 path_put(&path);
612out1:
613 deactivate_locked_super(s);
614out:
615 if (sbi) {
616 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
617 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
618 }
619 printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
620 return ERR_PTR(rc);
621}
622
623/**
624 * ecryptfs_kill_block_super
625 * @sb: The ecryptfs super block
626 *
627 * Used to bring the superblock down and free the private data.
628 */
629static void ecryptfs_kill_block_super(struct super_block *sb)
630{
631 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
632 kill_anon_super(sb);
633 if (!sb_info)
634 return;
635 ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
636 bdi_destroy(&sb_info->bdi);
637 kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
638}
639
640static struct file_system_type ecryptfs_fs_type = {
641 .owner = THIS_MODULE,
642 .name = "ecryptfs",
643 .mount = ecryptfs_mount,
644 .kill_sb = ecryptfs_kill_block_super,
645 .fs_flags = 0
646};
647MODULE_ALIAS_FS("ecryptfs");
648
649/**
650 * inode_info_init_once
651 *
652 * Initializes the ecryptfs_inode_info_cache when it is created
653 */
654static void
655inode_info_init_once(void *vptr)
656{
657 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
658
659 inode_init_once(&ei->vfs_inode);
660}
661
662static struct ecryptfs_cache_info {
663 struct kmem_cache **cache;
664 const char *name;
665 size_t size;
666 unsigned long flags;
667 void (*ctor)(void *obj);
668} ecryptfs_cache_infos[] = {
669 {
670 .cache = &ecryptfs_auth_tok_list_item_cache,
671 .name = "ecryptfs_auth_tok_list_item",
672 .size = sizeof(struct ecryptfs_auth_tok_list_item),
673 },
674 {
675 .cache = &ecryptfs_file_info_cache,
676 .name = "ecryptfs_file_cache",
677 .size = sizeof(struct ecryptfs_file_info),
678 },
679 {
680 .cache = &ecryptfs_dentry_info_cache,
681 .name = "ecryptfs_dentry_info_cache",
682 .size = sizeof(struct ecryptfs_dentry_info),
683 },
684 {
685 .cache = &ecryptfs_inode_info_cache,
686 .name = "ecryptfs_inode_cache",
687 .size = sizeof(struct ecryptfs_inode_info),
688 .flags = SLAB_ACCOUNT,
689 .ctor = inode_info_init_once,
690 },
691 {
692 .cache = &ecryptfs_sb_info_cache,
693 .name = "ecryptfs_sb_cache",
694 .size = sizeof(struct ecryptfs_sb_info),
695 },
696 {
697 .cache = &ecryptfs_header_cache,
698 .name = "ecryptfs_headers",
699 .size = PAGE_SIZE,
700 },
701 {
702 .cache = &ecryptfs_xattr_cache,
703 .name = "ecryptfs_xattr_cache",
704 .size = PAGE_SIZE,
705 },
706 {
707 .cache = &ecryptfs_key_record_cache,
708 .name = "ecryptfs_key_record_cache",
709 .size = sizeof(struct ecryptfs_key_record),
710 },
711 {
712 .cache = &ecryptfs_key_sig_cache,
713 .name = "ecryptfs_key_sig_cache",
714 .size = sizeof(struct ecryptfs_key_sig),
715 },
716 {
717 .cache = &ecryptfs_global_auth_tok_cache,
718 .name = "ecryptfs_global_auth_tok_cache",
719 .size = sizeof(struct ecryptfs_global_auth_tok),
720 },
721 {
722 .cache = &ecryptfs_key_tfm_cache,
723 .name = "ecryptfs_key_tfm_cache",
724 .size = sizeof(struct ecryptfs_key_tfm),
725 },
726};
727
728static void ecryptfs_free_kmem_caches(void)
729{
730 int i;
731
732 /*
733 * Make sure all delayed rcu free inodes are flushed before we
734 * destroy cache.
735 */
736 rcu_barrier();
737
738 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
739 struct ecryptfs_cache_info *info;
740
741 info = &ecryptfs_cache_infos[i];
742 kmem_cache_destroy(*(info->cache));
743 }
744}
745
746/**
747 * ecryptfs_init_kmem_caches
748 *
749 * Returns zero on success; non-zero otherwise
750 */
751static int ecryptfs_init_kmem_caches(void)
752{
753 int i;
754
755 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
756 struct ecryptfs_cache_info *info;
757
758 info = &ecryptfs_cache_infos[i];
759 *(info->cache) = kmem_cache_create(info->name, info->size, 0,
760 SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
761 if (!*(info->cache)) {
762 ecryptfs_free_kmem_caches();
763 ecryptfs_printk(KERN_WARNING, "%s: "
764 "kmem_cache_create failed\n",
765 info->name);
766 return -ENOMEM;
767 }
768 }
769 return 0;
770}
771
772static struct kobject *ecryptfs_kobj;
773
774static ssize_t version_show(struct kobject *kobj,
775 struct kobj_attribute *attr, char *buff)
776{
777 return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
778}
779
780static struct kobj_attribute version_attr = __ATTR_RO(version);
781
782static struct attribute *attributes[] = {
783 &version_attr.attr,
784 NULL,
785};
786
787static struct attribute_group attr_group = {
788 .attrs = attributes,
789};
790
791static int do_sysfs_registration(void)
792{
793 int rc;
794
795 ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
796 if (!ecryptfs_kobj) {
797 printk(KERN_ERR "Unable to create ecryptfs kset\n");
798 rc = -ENOMEM;
799 goto out;
800 }
801 rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
802 if (rc) {
803 printk(KERN_ERR
804 "Unable to create ecryptfs version attributes\n");
805 kobject_put(ecryptfs_kobj);
806 }
807out:
808 return rc;
809}
810
811static void do_sysfs_unregistration(void)
812{
813 sysfs_remove_group(ecryptfs_kobj, &attr_group);
814 kobject_put(ecryptfs_kobj);
815}
816
817static int __init ecryptfs_init(void)
818{
819 int rc;
820
821 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
822 rc = -EINVAL;
823 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
824 "larger than the host's page size, and so "
825 "eCryptfs cannot run on this system. The "
826 "default eCryptfs extent size is [%u] bytes; "
827 "the page size is [%lu] bytes.\n",
828 ECRYPTFS_DEFAULT_EXTENT_SIZE,
829 (unsigned long)PAGE_SIZE);
830 goto out;
831 }
832 rc = ecryptfs_init_kmem_caches();
833 if (rc) {
834 printk(KERN_ERR
835 "Failed to allocate one or more kmem_cache objects\n");
836 goto out;
837 }
838 rc = do_sysfs_registration();
839 if (rc) {
840 printk(KERN_ERR "sysfs registration failed\n");
841 goto out_free_kmem_caches;
842 }
843 rc = ecryptfs_init_kthread();
844 if (rc) {
845 printk(KERN_ERR "%s: kthread initialization failed; "
846 "rc = [%d]\n", __func__, rc);
847 goto out_do_sysfs_unregistration;
848 }
849 rc = ecryptfs_init_messaging();
850 if (rc) {
851 printk(KERN_ERR "Failure occurred while attempting to "
852 "initialize the communications channel to "
853 "ecryptfsd\n");
854 goto out_destroy_kthread;
855 }
856 rc = ecryptfs_init_crypto();
857 if (rc) {
858 printk(KERN_ERR "Failure whilst attempting to init crypto; "
859 "rc = [%d]\n", rc);
860 goto out_release_messaging;
861 }
862 rc = register_filesystem(&ecryptfs_fs_type);
863 if (rc) {
864 printk(KERN_ERR "Failed to register filesystem\n");
865 goto out_destroy_crypto;
866 }
867 if (ecryptfs_verbosity > 0)
868 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
869 "will be written to the syslog!\n", ecryptfs_verbosity);
870
871 goto out;
872out_destroy_crypto:
873 ecryptfs_destroy_crypto();
874out_release_messaging:
875 ecryptfs_release_messaging();
876out_destroy_kthread:
877 ecryptfs_destroy_kthread();
878out_do_sysfs_unregistration:
879 do_sysfs_unregistration();
880out_free_kmem_caches:
881 ecryptfs_free_kmem_caches();
882out:
883 return rc;
884}
885
886static void __exit ecryptfs_exit(void)
887{
888 int rc;
889
890 rc = ecryptfs_destroy_crypto();
891 if (rc)
892 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
893 "rc = [%d]\n", rc);
894 ecryptfs_release_messaging();
895 ecryptfs_destroy_kthread();
896 do_sysfs_unregistration();
897 unregister_filesystem(&ecryptfs_fs_type);
898 ecryptfs_free_kmem_caches();
899}
900
901MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
902MODULE_DESCRIPTION("eCryptfs");
903
904MODULE_LICENSE("GPL");
905
906module_init(ecryptfs_init)
907module_exit(ecryptfs_exit)
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * eCryptfs: Linux filesystem encryption layer
4 *
5 * Copyright (C) 1997-2003 Erez Zadok
6 * Copyright (C) 2001-2003 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. Thompson <mcthomps@us.ibm.com>
10 * Tyler Hicks <code@tyhicks.com>
11 */
12
13#include <linux/dcache.h>
14#include <linux/file.h>
15#include <linux/module.h>
16#include <linux/namei.h>
17#include <linux/skbuff.h>
18#include <linux/mount.h>
19#include <linux/pagemap.h>
20#include <linux/key.h>
21#include <linux/parser.h>
22#include <linux/fs_stack.h>
23#include <linux/slab.h>
24#include <linux/magic.h>
25#include "ecryptfs_kernel.h"
26
27/*
28 * Module parameter that defines the ecryptfs_verbosity level.
29 */
30int ecryptfs_verbosity = 0;
31
32module_param(ecryptfs_verbosity, int, 0);
33MODULE_PARM_DESC(ecryptfs_verbosity,
34 "Initial verbosity level (0 or 1; defaults to "
35 "0, which is Quiet)");
36
37/*
38 * Module parameter that defines the number of message buffer elements
39 */
40unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
41
42module_param(ecryptfs_message_buf_len, uint, 0);
43MODULE_PARM_DESC(ecryptfs_message_buf_len,
44 "Number of message buffer elements");
45
46/*
47 * Module parameter that defines the maximum guaranteed amount of time to wait
48 * for a response from ecryptfsd. The actual sleep time will be, more than
49 * likely, a small amount greater than this specified value, but only less if
50 * the message successfully arrives.
51 */
52signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
53
54module_param(ecryptfs_message_wait_timeout, long, 0);
55MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
56 "Maximum number of seconds that an operation will "
57 "sleep while waiting for a message response from "
58 "userspace");
59
60/*
61 * Module parameter that is an estimate of the maximum number of users
62 * that will be concurrently using eCryptfs. Set this to the right
63 * value to balance performance and memory use.
64 */
65unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
66
67module_param(ecryptfs_number_of_users, uint, 0);
68MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
69 "concurrent users of eCryptfs");
70
71void __ecryptfs_printk(const char *fmt, ...)
72{
73 va_list args;
74 va_start(args, fmt);
75 if (fmt[1] == '7') { /* KERN_DEBUG */
76 if (ecryptfs_verbosity >= 1)
77 vprintk(fmt, args);
78 } else
79 vprintk(fmt, args);
80 va_end(args);
81}
82
83/*
84 * ecryptfs_init_lower_file
85 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
86 * the lower dentry and the lower mount set
87 *
88 * eCryptfs only ever keeps a single open file for every lower
89 * inode. All I/O operations to the lower inode occur through that
90 * file. When the first eCryptfs dentry that interposes with the first
91 * lower dentry for that inode is created, this function creates the
92 * lower file struct and associates it with the eCryptfs
93 * inode. When all eCryptfs files associated with the inode are released, the
94 * file is closed.
95 *
96 * The lower file will be opened with read/write permissions, if
97 * possible. Otherwise, it is opened read-only.
98 *
99 * This function does nothing if a lower file is already
100 * associated with the eCryptfs inode.
101 *
102 * Returns zero on success; non-zero otherwise
103 */
104static int ecryptfs_init_lower_file(struct dentry *dentry,
105 struct file **lower_file)
106{
107 const struct cred *cred = current_cred();
108 const struct path *path = ecryptfs_dentry_to_lower_path(dentry);
109 int rc;
110
111 rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
112 cred);
113 if (rc) {
114 printk(KERN_ERR "Error opening lower file "
115 "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
116 "rc = [%d]\n", path->dentry, path->mnt, rc);
117 (*lower_file) = NULL;
118 }
119 return rc;
120}
121
122int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
123{
124 struct ecryptfs_inode_info *inode_info;
125 int count, rc = 0;
126
127 inode_info = ecryptfs_inode_to_private(inode);
128 mutex_lock(&inode_info->lower_file_mutex);
129 count = atomic_inc_return(&inode_info->lower_file_count);
130 if (WARN_ON_ONCE(count < 1))
131 rc = -EINVAL;
132 else if (count == 1) {
133 rc = ecryptfs_init_lower_file(dentry,
134 &inode_info->lower_file);
135 if (rc)
136 atomic_set(&inode_info->lower_file_count, 0);
137 }
138 mutex_unlock(&inode_info->lower_file_mutex);
139 return rc;
140}
141
142void ecryptfs_put_lower_file(struct inode *inode)
143{
144 struct ecryptfs_inode_info *inode_info;
145
146 inode_info = ecryptfs_inode_to_private(inode);
147 if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
148 &inode_info->lower_file_mutex)) {
149 filemap_write_and_wait(inode->i_mapping);
150 fput(inode_info->lower_file);
151 inode_info->lower_file = NULL;
152 mutex_unlock(&inode_info->lower_file_mutex);
153 }
154}
155
156enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
157 ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
158 ecryptfs_opt_ecryptfs_key_bytes,
159 ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
160 ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
161 ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
162 ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
163 ecryptfs_opt_check_dev_ruid,
164 ecryptfs_opt_err };
165
166static const match_table_t tokens = {
167 {ecryptfs_opt_sig, "sig=%s"},
168 {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
169 {ecryptfs_opt_cipher, "cipher=%s"},
170 {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
171 {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
172 {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
173 {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
174 {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
175 {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
176 {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
177 {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
178 {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
179 {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
180 {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
181 {ecryptfs_opt_err, NULL}
182};
183
184static int ecryptfs_init_global_auth_toks(
185 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
186{
187 struct ecryptfs_global_auth_tok *global_auth_tok;
188 struct ecryptfs_auth_tok *auth_tok;
189 int rc = 0;
190
191 list_for_each_entry(global_auth_tok,
192 &mount_crypt_stat->global_auth_tok_list,
193 mount_crypt_stat_list) {
194 rc = ecryptfs_keyring_auth_tok_for_sig(
195 &global_auth_tok->global_auth_tok_key, &auth_tok,
196 global_auth_tok->sig);
197 if (rc) {
198 printk(KERN_ERR "Could not find valid key in user "
199 "session keyring for sig specified in mount "
200 "option: [%s]\n", global_auth_tok->sig);
201 global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
202 goto out;
203 } else {
204 global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
205 up_write(&(global_auth_tok->global_auth_tok_key)->sem);
206 }
207 }
208out:
209 return rc;
210}
211
212static void ecryptfs_init_mount_crypt_stat(
213 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
214{
215 memset((void *)mount_crypt_stat, 0,
216 sizeof(struct ecryptfs_mount_crypt_stat));
217 INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
218 mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
219 mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
220}
221
222/**
223 * ecryptfs_parse_options
224 * @sbi: The ecryptfs super block
225 * @options: The options passed to the kernel
226 * @check_ruid: set to 1 if device uid should be checked against the ruid
227 *
228 * Parse mount options:
229 * debug=N - ecryptfs_verbosity level for debug output
230 * sig=XXX - description(signature) of the key to use
231 *
232 * Returns the dentry object of the lower-level (lower/interposed)
233 * directory; We want to mount our stackable file system on top of
234 * that lower directory.
235 *
236 * The signature of the key to use must be the description of a key
237 * already in the keyring. Mounting will fail if the key can not be
238 * found.
239 *
240 * Returns zero on success; non-zero on error
241 */
242static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
243 uid_t *check_ruid)
244{
245 char *p;
246 int rc = 0;
247 int sig_set = 0;
248 int cipher_name_set = 0;
249 int fn_cipher_name_set = 0;
250 int cipher_key_bytes;
251 int cipher_key_bytes_set = 0;
252 int fn_cipher_key_bytes;
253 int fn_cipher_key_bytes_set = 0;
254 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
255 &sbi->mount_crypt_stat;
256 substring_t args[MAX_OPT_ARGS];
257 int token;
258 char *sig_src;
259 char *cipher_name_dst;
260 char *cipher_name_src;
261 char *fn_cipher_name_dst;
262 char *fn_cipher_name_src;
263 char *fnek_dst;
264 char *fnek_src;
265 char *cipher_key_bytes_src;
266 char *fn_cipher_key_bytes_src;
267 u8 cipher_code;
268
269 *check_ruid = 0;
270
271 if (!options) {
272 rc = -EINVAL;
273 goto out;
274 }
275 ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
276 while ((p = strsep(&options, ",")) != NULL) {
277 if (!*p)
278 continue;
279 token = match_token(p, tokens, args);
280 switch (token) {
281 case ecryptfs_opt_sig:
282 case ecryptfs_opt_ecryptfs_sig:
283 sig_src = args[0].from;
284 rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
285 sig_src, 0);
286 if (rc) {
287 printk(KERN_ERR "Error attempting to register "
288 "global sig; rc = [%d]\n", rc);
289 goto out;
290 }
291 sig_set = 1;
292 break;
293 case ecryptfs_opt_cipher:
294 case ecryptfs_opt_ecryptfs_cipher:
295 cipher_name_src = args[0].from;
296 cipher_name_dst =
297 mount_crypt_stat->
298 global_default_cipher_name;
299 strncpy(cipher_name_dst, cipher_name_src,
300 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
301 cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
302 cipher_name_set = 1;
303 break;
304 case ecryptfs_opt_ecryptfs_key_bytes:
305 cipher_key_bytes_src = args[0].from;
306 cipher_key_bytes =
307 (int)simple_strtol(cipher_key_bytes_src,
308 &cipher_key_bytes_src, 0);
309 mount_crypt_stat->global_default_cipher_key_size =
310 cipher_key_bytes;
311 cipher_key_bytes_set = 1;
312 break;
313 case ecryptfs_opt_passthrough:
314 mount_crypt_stat->flags |=
315 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
316 break;
317 case ecryptfs_opt_xattr_metadata:
318 mount_crypt_stat->flags |=
319 ECRYPTFS_XATTR_METADATA_ENABLED;
320 break;
321 case ecryptfs_opt_encrypted_view:
322 mount_crypt_stat->flags |=
323 ECRYPTFS_XATTR_METADATA_ENABLED;
324 mount_crypt_stat->flags |=
325 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
326 break;
327 case ecryptfs_opt_fnek_sig:
328 fnek_src = args[0].from;
329 fnek_dst =
330 mount_crypt_stat->global_default_fnek_sig;
331 strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
332 mount_crypt_stat->global_default_fnek_sig[
333 ECRYPTFS_SIG_SIZE_HEX] = '\0';
334 rc = ecryptfs_add_global_auth_tok(
335 mount_crypt_stat,
336 mount_crypt_stat->global_default_fnek_sig,
337 ECRYPTFS_AUTH_TOK_FNEK);
338 if (rc) {
339 printk(KERN_ERR "Error attempting to register "
340 "global fnek sig [%s]; rc = [%d]\n",
341 mount_crypt_stat->global_default_fnek_sig,
342 rc);
343 goto out;
344 }
345 mount_crypt_stat->flags |=
346 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
347 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
348 break;
349 case ecryptfs_opt_fn_cipher:
350 fn_cipher_name_src = args[0].from;
351 fn_cipher_name_dst =
352 mount_crypt_stat->global_default_fn_cipher_name;
353 strncpy(fn_cipher_name_dst, fn_cipher_name_src,
354 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
355 mount_crypt_stat->global_default_fn_cipher_name[
356 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
357 fn_cipher_name_set = 1;
358 break;
359 case ecryptfs_opt_fn_cipher_key_bytes:
360 fn_cipher_key_bytes_src = args[0].from;
361 fn_cipher_key_bytes =
362 (int)simple_strtol(fn_cipher_key_bytes_src,
363 &fn_cipher_key_bytes_src, 0);
364 mount_crypt_stat->global_default_fn_cipher_key_bytes =
365 fn_cipher_key_bytes;
366 fn_cipher_key_bytes_set = 1;
367 break;
368 case ecryptfs_opt_unlink_sigs:
369 mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
370 break;
371 case ecryptfs_opt_mount_auth_tok_only:
372 mount_crypt_stat->flags |=
373 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
374 break;
375 case ecryptfs_opt_check_dev_ruid:
376 *check_ruid = 1;
377 break;
378 case ecryptfs_opt_err:
379 default:
380 printk(KERN_WARNING
381 "%s: eCryptfs: unrecognized option [%s]\n",
382 __func__, p);
383 }
384 }
385 if (!sig_set) {
386 rc = -EINVAL;
387 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
388 "auth tok signature as a mount "
389 "parameter; see the eCryptfs README\n");
390 goto out;
391 }
392 if (!cipher_name_set) {
393 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
394
395 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
396 strcpy(mount_crypt_stat->global_default_cipher_name,
397 ECRYPTFS_DEFAULT_CIPHER);
398 }
399 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
400 && !fn_cipher_name_set)
401 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
402 mount_crypt_stat->global_default_cipher_name);
403 if (!cipher_key_bytes_set)
404 mount_crypt_stat->global_default_cipher_key_size = 0;
405 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
406 && !fn_cipher_key_bytes_set)
407 mount_crypt_stat->global_default_fn_cipher_key_bytes =
408 mount_crypt_stat->global_default_cipher_key_size;
409
410 cipher_code = ecryptfs_code_for_cipher_string(
411 mount_crypt_stat->global_default_cipher_name,
412 mount_crypt_stat->global_default_cipher_key_size);
413 if (!cipher_code) {
414 ecryptfs_printk(KERN_ERR,
415 "eCryptfs doesn't support cipher: %s\n",
416 mount_crypt_stat->global_default_cipher_name);
417 rc = -EINVAL;
418 goto out;
419 }
420
421 mutex_lock(&key_tfm_list_mutex);
422 if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
423 NULL)) {
424 rc = ecryptfs_add_new_key_tfm(
425 NULL, mount_crypt_stat->global_default_cipher_name,
426 mount_crypt_stat->global_default_cipher_key_size);
427 if (rc) {
428 printk(KERN_ERR "Error attempting to initialize "
429 "cipher with name = [%s] and key size = [%td]; "
430 "rc = [%d]\n",
431 mount_crypt_stat->global_default_cipher_name,
432 mount_crypt_stat->global_default_cipher_key_size,
433 rc);
434 rc = -EINVAL;
435 mutex_unlock(&key_tfm_list_mutex);
436 goto out;
437 }
438 }
439 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
440 && !ecryptfs_tfm_exists(
441 mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
442 rc = ecryptfs_add_new_key_tfm(
443 NULL, mount_crypt_stat->global_default_fn_cipher_name,
444 mount_crypt_stat->global_default_fn_cipher_key_bytes);
445 if (rc) {
446 printk(KERN_ERR "Error attempting to initialize "
447 "cipher with name = [%s] and key size = [%td]; "
448 "rc = [%d]\n",
449 mount_crypt_stat->global_default_fn_cipher_name,
450 mount_crypt_stat->global_default_fn_cipher_key_bytes,
451 rc);
452 rc = -EINVAL;
453 mutex_unlock(&key_tfm_list_mutex);
454 goto out;
455 }
456 }
457 mutex_unlock(&key_tfm_list_mutex);
458 rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
459 if (rc)
460 printk(KERN_WARNING "One or more global auth toks could not "
461 "properly register; rc = [%d]\n", rc);
462out:
463 return rc;
464}
465
466struct kmem_cache *ecryptfs_sb_info_cache;
467static struct file_system_type ecryptfs_fs_type;
468
469/*
470 * ecryptfs_mount
471 * @fs_type: The filesystem type that the superblock should belong to
472 * @flags: The flags associated with the mount
473 * @dev_name: The path to mount over
474 * @raw_data: The options passed into the kernel
475 */
476static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
477 const char *dev_name, void *raw_data)
478{
479 struct super_block *s;
480 struct ecryptfs_sb_info *sbi;
481 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
482 struct ecryptfs_dentry_info *root_info;
483 const char *err = "Getting sb failed";
484 struct inode *inode;
485 struct path path;
486 uid_t check_ruid;
487 int rc;
488
489 sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
490 if (!sbi) {
491 rc = -ENOMEM;
492 goto out;
493 }
494
495 if (!dev_name) {
496 rc = -EINVAL;
497 err = "Device name cannot be null";
498 goto out;
499 }
500
501 rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
502 if (rc) {
503 err = "Error parsing options";
504 goto out;
505 }
506 mount_crypt_stat = &sbi->mount_crypt_stat;
507
508 s = sget(fs_type, NULL, set_anon_super, flags, NULL);
509 if (IS_ERR(s)) {
510 rc = PTR_ERR(s);
511 goto out;
512 }
513
514 rc = super_setup_bdi(s);
515 if (rc)
516 goto out1;
517
518 ecryptfs_set_superblock_private(s, sbi);
519
520 /* ->kill_sb() will take care of sbi after that point */
521 sbi = NULL;
522 s->s_op = &ecryptfs_sops;
523 s->s_xattr = ecryptfs_xattr_handlers;
524 s->s_d_op = &ecryptfs_dops;
525
526 err = "Reading sb failed";
527 rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
528 if (rc) {
529 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
530 goto out1;
531 }
532 if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
533 rc = -EINVAL;
534 printk(KERN_ERR "Mount on filesystem of type "
535 "eCryptfs explicitly disallowed due to "
536 "known incompatibilities\n");
537 goto out_free;
538 }
539
540 if (is_idmapped_mnt(path.mnt)) {
541 rc = -EINVAL;
542 printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
543 goto out_free;
544 }
545
546 if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
547 rc = -EPERM;
548 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
549 "requested user (uid: %d)\n",
550 i_uid_read(d_inode(path.dentry)),
551 from_kuid(&init_user_ns, current_uid()));
552 goto out_free;
553 }
554
555 ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
556
557 /**
558 * Set the POSIX ACL flag based on whether they're enabled in the lower
559 * mount.
560 */
561 s->s_flags = flags & ~SB_POSIXACL;
562 s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
563
564 /**
565 * Force a read-only eCryptfs mount when:
566 * 1) The lower mount is ro
567 * 2) The ecryptfs_encrypted_view mount option is specified
568 */
569 if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
570 s->s_flags |= SB_RDONLY;
571
572 s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
573 s->s_blocksize = path.dentry->d_sb->s_blocksize;
574 s->s_magic = ECRYPTFS_SUPER_MAGIC;
575 s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
576
577 rc = -EINVAL;
578 if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
579 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
580 goto out_free;
581 }
582
583 inode = ecryptfs_get_inode(d_inode(path.dentry), s);
584 rc = PTR_ERR(inode);
585 if (IS_ERR(inode))
586 goto out_free;
587
588 s->s_root = d_make_root(inode);
589 if (!s->s_root) {
590 rc = -ENOMEM;
591 goto out_free;
592 }
593
594 rc = -ENOMEM;
595 root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
596 if (!root_info)
597 goto out_free;
598
599 /* ->kill_sb() will take care of root_info */
600 ecryptfs_set_dentry_private(s->s_root, root_info);
601 root_info->lower_path = path;
602
603 s->s_flags |= SB_ACTIVE;
604 return dget(s->s_root);
605
606out_free:
607 path_put(&path);
608out1:
609 deactivate_locked_super(s);
610out:
611 if (sbi) {
612 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
613 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
614 }
615 printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
616 return ERR_PTR(rc);
617}
618
619/**
620 * ecryptfs_kill_block_super
621 * @sb: The ecryptfs super block
622 *
623 * Used to bring the superblock down and free the private data.
624 */
625static void ecryptfs_kill_block_super(struct super_block *sb)
626{
627 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
628 kill_anon_super(sb);
629 if (!sb_info)
630 return;
631 ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
632 kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
633}
634
635static struct file_system_type ecryptfs_fs_type = {
636 .owner = THIS_MODULE,
637 .name = "ecryptfs",
638 .mount = ecryptfs_mount,
639 .kill_sb = ecryptfs_kill_block_super,
640 .fs_flags = 0
641};
642MODULE_ALIAS_FS("ecryptfs");
643
644/*
645 * inode_info_init_once
646 *
647 * Initializes the ecryptfs_inode_info_cache when it is created
648 */
649static void
650inode_info_init_once(void *vptr)
651{
652 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
653
654 inode_init_once(&ei->vfs_inode);
655}
656
657static struct ecryptfs_cache_info {
658 struct kmem_cache **cache;
659 const char *name;
660 size_t size;
661 slab_flags_t flags;
662 void (*ctor)(void *obj);
663} ecryptfs_cache_infos[] = {
664 {
665 .cache = &ecryptfs_auth_tok_list_item_cache,
666 .name = "ecryptfs_auth_tok_list_item",
667 .size = sizeof(struct ecryptfs_auth_tok_list_item),
668 },
669 {
670 .cache = &ecryptfs_file_info_cache,
671 .name = "ecryptfs_file_cache",
672 .size = sizeof(struct ecryptfs_file_info),
673 },
674 {
675 .cache = &ecryptfs_dentry_info_cache,
676 .name = "ecryptfs_dentry_info_cache",
677 .size = sizeof(struct ecryptfs_dentry_info),
678 },
679 {
680 .cache = &ecryptfs_inode_info_cache,
681 .name = "ecryptfs_inode_cache",
682 .size = sizeof(struct ecryptfs_inode_info),
683 .flags = SLAB_ACCOUNT,
684 .ctor = inode_info_init_once,
685 },
686 {
687 .cache = &ecryptfs_sb_info_cache,
688 .name = "ecryptfs_sb_cache",
689 .size = sizeof(struct ecryptfs_sb_info),
690 },
691 {
692 .cache = &ecryptfs_header_cache,
693 .name = "ecryptfs_headers",
694 .size = PAGE_SIZE,
695 },
696 {
697 .cache = &ecryptfs_xattr_cache,
698 .name = "ecryptfs_xattr_cache",
699 .size = PAGE_SIZE,
700 },
701 {
702 .cache = &ecryptfs_key_record_cache,
703 .name = "ecryptfs_key_record_cache",
704 .size = sizeof(struct ecryptfs_key_record),
705 },
706 {
707 .cache = &ecryptfs_key_sig_cache,
708 .name = "ecryptfs_key_sig_cache",
709 .size = sizeof(struct ecryptfs_key_sig),
710 },
711 {
712 .cache = &ecryptfs_global_auth_tok_cache,
713 .name = "ecryptfs_global_auth_tok_cache",
714 .size = sizeof(struct ecryptfs_global_auth_tok),
715 },
716 {
717 .cache = &ecryptfs_key_tfm_cache,
718 .name = "ecryptfs_key_tfm_cache",
719 .size = sizeof(struct ecryptfs_key_tfm),
720 },
721};
722
723static void ecryptfs_free_kmem_caches(void)
724{
725 int i;
726
727 /*
728 * Make sure all delayed rcu free inodes are flushed before we
729 * destroy cache.
730 */
731 rcu_barrier();
732
733 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
734 struct ecryptfs_cache_info *info;
735
736 info = &ecryptfs_cache_infos[i];
737 kmem_cache_destroy(*(info->cache));
738 }
739}
740
741/**
742 * ecryptfs_init_kmem_caches
743 *
744 * Returns zero on success; non-zero otherwise
745 */
746static int ecryptfs_init_kmem_caches(void)
747{
748 int i;
749
750 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
751 struct ecryptfs_cache_info *info;
752
753 info = &ecryptfs_cache_infos[i];
754 *(info->cache) = kmem_cache_create(info->name, info->size, 0,
755 SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
756 if (!*(info->cache)) {
757 ecryptfs_free_kmem_caches();
758 ecryptfs_printk(KERN_WARNING, "%s: "
759 "kmem_cache_create failed\n",
760 info->name);
761 return -ENOMEM;
762 }
763 }
764 return 0;
765}
766
767static struct kobject *ecryptfs_kobj;
768
769static ssize_t version_show(struct kobject *kobj,
770 struct kobj_attribute *attr, char *buff)
771{
772 return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
773}
774
775static struct kobj_attribute version_attr = __ATTR_RO(version);
776
777static struct attribute *attributes[] = {
778 &version_attr.attr,
779 NULL,
780};
781
782static const struct attribute_group attr_group = {
783 .attrs = attributes,
784};
785
786static int do_sysfs_registration(void)
787{
788 int rc;
789
790 ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
791 if (!ecryptfs_kobj) {
792 printk(KERN_ERR "Unable to create ecryptfs kset\n");
793 rc = -ENOMEM;
794 goto out;
795 }
796 rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
797 if (rc) {
798 printk(KERN_ERR
799 "Unable to create ecryptfs version attributes\n");
800 kobject_put(ecryptfs_kobj);
801 }
802out:
803 return rc;
804}
805
806static void do_sysfs_unregistration(void)
807{
808 sysfs_remove_group(ecryptfs_kobj, &attr_group);
809 kobject_put(ecryptfs_kobj);
810}
811
812static int __init ecryptfs_init(void)
813{
814 int rc;
815
816 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
817 rc = -EINVAL;
818 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
819 "larger than the host's page size, and so "
820 "eCryptfs cannot run on this system. The "
821 "default eCryptfs extent size is [%u] bytes; "
822 "the page size is [%lu] bytes.\n",
823 ECRYPTFS_DEFAULT_EXTENT_SIZE,
824 (unsigned long)PAGE_SIZE);
825 goto out;
826 }
827 rc = ecryptfs_init_kmem_caches();
828 if (rc) {
829 printk(KERN_ERR
830 "Failed to allocate one or more kmem_cache objects\n");
831 goto out;
832 }
833 rc = do_sysfs_registration();
834 if (rc) {
835 printk(KERN_ERR "sysfs registration failed\n");
836 goto out_free_kmem_caches;
837 }
838 rc = ecryptfs_init_kthread();
839 if (rc) {
840 printk(KERN_ERR "%s: kthread initialization failed; "
841 "rc = [%d]\n", __func__, rc);
842 goto out_do_sysfs_unregistration;
843 }
844 rc = ecryptfs_init_messaging();
845 if (rc) {
846 printk(KERN_ERR "Failure occurred while attempting to "
847 "initialize the communications channel to "
848 "ecryptfsd\n");
849 goto out_destroy_kthread;
850 }
851 rc = ecryptfs_init_crypto();
852 if (rc) {
853 printk(KERN_ERR "Failure whilst attempting to init crypto; "
854 "rc = [%d]\n", rc);
855 goto out_release_messaging;
856 }
857 rc = register_filesystem(&ecryptfs_fs_type);
858 if (rc) {
859 printk(KERN_ERR "Failed to register filesystem\n");
860 goto out_destroy_crypto;
861 }
862 if (ecryptfs_verbosity > 0)
863 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
864 "will be written to the syslog!\n", ecryptfs_verbosity);
865
866 goto out;
867out_destroy_crypto:
868 ecryptfs_destroy_crypto();
869out_release_messaging:
870 ecryptfs_release_messaging();
871out_destroy_kthread:
872 ecryptfs_destroy_kthread();
873out_do_sysfs_unregistration:
874 do_sysfs_unregistration();
875out_free_kmem_caches:
876 ecryptfs_free_kmem_caches();
877out:
878 return rc;
879}
880
881static void __exit ecryptfs_exit(void)
882{
883 int rc;
884
885 rc = ecryptfs_destroy_crypto();
886 if (rc)
887 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
888 "rc = [%d]\n", rc);
889 ecryptfs_release_messaging();
890 ecryptfs_destroy_kthread();
891 do_sysfs_unregistration();
892 unregister_filesystem(&ecryptfs_fs_type);
893 ecryptfs_free_kmem_caches();
894}
895
896MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
897MODULE_DESCRIPTION("eCryptfs");
898
899MODULE_LICENSE("GPL");
900
901module_init(ecryptfs_init)
902module_exit(ecryptfs_exit)