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 "ecryptfs_kernel.h"
39
40 /**
41 * Module parameter that defines the ecryptfs_verbosity level.
42 */
43 int ecryptfs_verbosity = 0;
44
45 module_param(ecryptfs_verbosity, int, 0);
46 MODULE_PARM_DESC(ecryptfs_verbosity,
47 "Initial verbosity level (0 or 1; defaults to "
48 "0, which is Quiet)");
49
50 /**
51 * Module parameter that defines the number of message buffer elements
52 */
53 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
54
55 module_param(ecryptfs_message_buf_len, uint, 0);
56 MODULE_PARM_DESC(ecryptfs_message_buf_len,
57 "Number of message buffer elements");
58
59 /**
60 * Module parameter that defines the maximum guaranteed amount of time to wait
61 * for a response from ecryptfsd. The actual sleep time will be, more than
62 * likely, a small amount greater than this specified value, but only less if
63 * the message successfully arrives.
64 */
65 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
66
67 module_param(ecryptfs_message_wait_timeout, long, 0);
68 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
69 "Maximum number of seconds that an operation will "
70 "sleep while waiting for a message response from "
71 "userspace");
72
73 /**
74 * Module parameter that is an estimate of the maximum number of users
75 * that will be concurrently using eCryptfs. Set this to the right
76 * value to balance performance and memory use.
77 */
78 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
79
80 module_param(ecryptfs_number_of_users, uint, 0);
81 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
82 "concurrent users of eCryptfs");
83
__ecryptfs_printk(const char * fmt,...)84 void __ecryptfs_printk(const char *fmt, ...)
85 {
86 va_list args;
87 va_start(args, fmt);
88 if (fmt[1] == '7') { /* KERN_DEBUG */
89 if (ecryptfs_verbosity >= 1)
90 vprintk(fmt, args);
91 } else
92 vprintk(fmt, args);
93 va_end(args);
94 }
95
96 /**
97 * ecryptfs_init_persistent_file
98 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
99 * the lower dentry and the lower mount set
100 *
101 * eCryptfs only ever keeps a single open file for every lower
102 * inode. All I/O operations to the lower inode occur through that
103 * file. When the first eCryptfs dentry that interposes with the first
104 * lower dentry for that inode is created, this function creates the
105 * persistent file struct and associates it with the eCryptfs
106 * inode. When the eCryptfs inode is destroyed, the file is closed.
107 *
108 * The persistent file will be opened with read/write permissions, if
109 * possible. Otherwise, it is opened read-only.
110 *
111 * This function does nothing if a lower persistent file is already
112 * associated with the eCryptfs inode.
113 *
114 * Returns zero on success; non-zero otherwise
115 */
ecryptfs_init_persistent_file(struct dentry * ecryptfs_dentry)116 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
117 {
118 const struct cred *cred = current_cred();
119 struct ecryptfs_inode_info *inode_info =
120 ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
121 int rc = 0;
122
123 mutex_lock(&inode_info->lower_file_mutex);
124 if (!inode_info->lower_file) {
125 struct dentry *lower_dentry;
126 struct vfsmount *lower_mnt =
127 ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
128
129 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
130 rc = ecryptfs_privileged_open(&inode_info->lower_file,
131 lower_dentry, lower_mnt, cred);
132 if (rc || IS_ERR(inode_info->lower_file)) {
133 printk(KERN_ERR "Error opening lower persistent file "
134 "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
135 "rc = [%d]\n", lower_dentry, lower_mnt, rc);
136 rc = PTR_ERR(inode_info->lower_file);
137 inode_info->lower_file = NULL;
138 }
139 }
140 mutex_unlock(&inode_info->lower_file_mutex);
141 return rc;
142 }
143
144 /**
145 * ecryptfs_interpose
146 * @lower_dentry: Existing dentry in the lower filesystem
147 * @dentry: ecryptfs' dentry
148 * @sb: ecryptfs's super_block
149 * @flags: flags to govern behavior of interpose procedure
150 *
151 * Interposes upper and lower dentries.
152 *
153 * Returns zero on success; non-zero otherwise
154 */
ecryptfs_interpose(struct dentry * lower_dentry,struct dentry * dentry,struct super_block * sb,u32 flags)155 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
156 struct super_block *sb, u32 flags)
157 {
158 struct inode *lower_inode;
159 struct inode *inode;
160 int rc = 0;
161
162 lower_inode = lower_dentry->d_inode;
163 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
164 rc = -EXDEV;
165 goto out;
166 }
167 if (!igrab(lower_inode)) {
168 rc = -ESTALE;
169 goto out;
170 }
171 inode = iget5_locked(sb, (unsigned long)lower_inode,
172 ecryptfs_inode_test, ecryptfs_inode_set,
173 lower_inode);
174 if (!inode) {
175 rc = -EACCES;
176 iput(lower_inode);
177 goto out;
178 }
179 if (inode->i_state & I_NEW)
180 unlock_new_inode(inode);
181 else
182 iput(lower_inode);
183 if (S_ISLNK(lower_inode->i_mode))
184 inode->i_op = &ecryptfs_symlink_iops;
185 else if (S_ISDIR(lower_inode->i_mode))
186 inode->i_op = &ecryptfs_dir_iops;
187 if (S_ISDIR(lower_inode->i_mode))
188 inode->i_fop = &ecryptfs_dir_fops;
189 if (special_file(lower_inode->i_mode))
190 init_special_inode(inode, lower_inode->i_mode,
191 lower_inode->i_rdev);
192 dentry->d_op = &ecryptfs_dops;
193 if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
194 d_add(dentry, inode);
195 else
196 d_instantiate(dentry, inode);
197 fsstack_copy_attr_all(inode, lower_inode, NULL);
198 /* This size will be overwritten for real files w/ headers and
199 * other metadata */
200 fsstack_copy_inode_size(inode, lower_inode);
201 out:
202 return rc;
203 }
204
205 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
206 ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
207 ecryptfs_opt_ecryptfs_key_bytes,
208 ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
209 ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
210 ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
211 ecryptfs_opt_err };
212
213 static const match_table_t tokens = {
214 {ecryptfs_opt_sig, "sig=%s"},
215 {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
216 {ecryptfs_opt_cipher, "cipher=%s"},
217 {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
218 {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
219 {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
220 {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
221 {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
222 {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
223 {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
224 {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
225 {ecryptfs_opt_err, NULL}
226 };
227
ecryptfs_init_global_auth_toks(struct ecryptfs_mount_crypt_stat * mount_crypt_stat)228 static int ecryptfs_init_global_auth_toks(
229 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
230 {
231 struct ecryptfs_global_auth_tok *global_auth_tok;
232 int rc = 0;
233
234 list_for_each_entry(global_auth_tok,
235 &mount_crypt_stat->global_auth_tok_list,
236 mount_crypt_stat_list) {
237 rc = ecryptfs_keyring_auth_tok_for_sig(
238 &global_auth_tok->global_auth_tok_key,
239 &global_auth_tok->global_auth_tok,
240 global_auth_tok->sig);
241 if (rc) {
242 printk(KERN_ERR "Could not find valid key in user "
243 "session keyring for sig specified in mount "
244 "option: [%s]\n", global_auth_tok->sig);
245 global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
246 goto out;
247 } else
248 global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
249 }
250 out:
251 return rc;
252 }
253
ecryptfs_init_mount_crypt_stat(struct ecryptfs_mount_crypt_stat * mount_crypt_stat)254 static void ecryptfs_init_mount_crypt_stat(
255 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
256 {
257 memset((void *)mount_crypt_stat, 0,
258 sizeof(struct ecryptfs_mount_crypt_stat));
259 INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
260 mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
261 mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
262 }
263
264 /**
265 * ecryptfs_parse_options
266 * @sb: The ecryptfs super block
267 * @options: The options pased to the kernel
268 *
269 * Parse mount options:
270 * debug=N - ecryptfs_verbosity level for debug output
271 * sig=XXX - description(signature) of the key to use
272 *
273 * Returns the dentry object of the lower-level (lower/interposed)
274 * directory; We want to mount our stackable file system on top of
275 * that lower directory.
276 *
277 * The signature of the key to use must be the description of a key
278 * already in the keyring. Mounting will fail if the key can not be
279 * found.
280 *
281 * Returns zero on success; non-zero on error
282 */
ecryptfs_parse_options(struct super_block * sb,char * options)283 static int ecryptfs_parse_options(struct super_block *sb, char *options)
284 {
285 char *p;
286 int rc = 0;
287 int sig_set = 0;
288 int cipher_name_set = 0;
289 int fn_cipher_name_set = 0;
290 int cipher_key_bytes;
291 int cipher_key_bytes_set = 0;
292 int fn_cipher_key_bytes;
293 int fn_cipher_key_bytes_set = 0;
294 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
295 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
296 substring_t args[MAX_OPT_ARGS];
297 int token;
298 char *sig_src;
299 char *cipher_name_dst;
300 char *cipher_name_src;
301 char *fn_cipher_name_dst;
302 char *fn_cipher_name_src;
303 char *fnek_dst;
304 char *fnek_src;
305 char *cipher_key_bytes_src;
306 char *fn_cipher_key_bytes_src;
307
308 if (!options) {
309 rc = -EINVAL;
310 goto out;
311 }
312 ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
313 while ((p = strsep(&options, ",")) != NULL) {
314 if (!*p)
315 continue;
316 token = match_token(p, tokens, args);
317 switch (token) {
318 case ecryptfs_opt_sig:
319 case ecryptfs_opt_ecryptfs_sig:
320 sig_src = args[0].from;
321 rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
322 sig_src, 0);
323 if (rc) {
324 printk(KERN_ERR "Error attempting to register "
325 "global sig; rc = [%d]\n", rc);
326 goto out;
327 }
328 sig_set = 1;
329 break;
330 case ecryptfs_opt_cipher:
331 case ecryptfs_opt_ecryptfs_cipher:
332 cipher_name_src = args[0].from;
333 cipher_name_dst =
334 mount_crypt_stat->
335 global_default_cipher_name;
336 strncpy(cipher_name_dst, cipher_name_src,
337 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
338 cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
339 cipher_name_set = 1;
340 break;
341 case ecryptfs_opt_ecryptfs_key_bytes:
342 cipher_key_bytes_src = args[0].from;
343 cipher_key_bytes =
344 (int)simple_strtol(cipher_key_bytes_src,
345 &cipher_key_bytes_src, 0);
346 mount_crypt_stat->global_default_cipher_key_size =
347 cipher_key_bytes;
348 cipher_key_bytes_set = 1;
349 break;
350 case ecryptfs_opt_passthrough:
351 mount_crypt_stat->flags |=
352 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
353 break;
354 case ecryptfs_opt_xattr_metadata:
355 mount_crypt_stat->flags |=
356 ECRYPTFS_XATTR_METADATA_ENABLED;
357 break;
358 case ecryptfs_opt_encrypted_view:
359 mount_crypt_stat->flags |=
360 ECRYPTFS_XATTR_METADATA_ENABLED;
361 mount_crypt_stat->flags |=
362 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
363 break;
364 case ecryptfs_opt_fnek_sig:
365 fnek_src = args[0].from;
366 fnek_dst =
367 mount_crypt_stat->global_default_fnek_sig;
368 strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
369 mount_crypt_stat->global_default_fnek_sig[
370 ECRYPTFS_SIG_SIZE_HEX] = '\0';
371 rc = ecryptfs_add_global_auth_tok(
372 mount_crypt_stat,
373 mount_crypt_stat->global_default_fnek_sig,
374 ECRYPTFS_AUTH_TOK_FNEK);
375 if (rc) {
376 printk(KERN_ERR "Error attempting to register "
377 "global fnek sig [%s]; rc = [%d]\n",
378 mount_crypt_stat->global_default_fnek_sig,
379 rc);
380 goto out;
381 }
382 mount_crypt_stat->flags |=
383 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
384 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
385 break;
386 case ecryptfs_opt_fn_cipher:
387 fn_cipher_name_src = args[0].from;
388 fn_cipher_name_dst =
389 mount_crypt_stat->global_default_fn_cipher_name;
390 strncpy(fn_cipher_name_dst, fn_cipher_name_src,
391 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
392 mount_crypt_stat->global_default_fn_cipher_name[
393 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
394 fn_cipher_name_set = 1;
395 break;
396 case ecryptfs_opt_fn_cipher_key_bytes:
397 fn_cipher_key_bytes_src = args[0].from;
398 fn_cipher_key_bytes =
399 (int)simple_strtol(fn_cipher_key_bytes_src,
400 &fn_cipher_key_bytes_src, 0);
401 mount_crypt_stat->global_default_fn_cipher_key_bytes =
402 fn_cipher_key_bytes;
403 fn_cipher_key_bytes_set = 1;
404 break;
405 case ecryptfs_opt_err:
406 default:
407 printk(KERN_WARNING
408 "%s: eCryptfs: unrecognized option [%s]\n",
409 __func__, p);
410 }
411 }
412 if (!sig_set) {
413 rc = -EINVAL;
414 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
415 "auth tok signature as a mount "
416 "parameter; see the eCryptfs README\n");
417 goto out;
418 }
419 if (!cipher_name_set) {
420 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
421
422 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
423 strcpy(mount_crypt_stat->global_default_cipher_name,
424 ECRYPTFS_DEFAULT_CIPHER);
425 }
426 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
427 && !fn_cipher_name_set)
428 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
429 mount_crypt_stat->global_default_cipher_name);
430 if (!cipher_key_bytes_set)
431 mount_crypt_stat->global_default_cipher_key_size = 0;
432 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
433 && !fn_cipher_key_bytes_set)
434 mount_crypt_stat->global_default_fn_cipher_key_bytes =
435 mount_crypt_stat->global_default_cipher_key_size;
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
483 /**
484 * ecryptfs_fill_super
485 * @sb: The ecryptfs super block
486 * @raw_data: The options passed to mount
487 * @silent: Not used but required by function prototype
488 *
489 * Sets up what we can of the sb, rest is done in ecryptfs_read_super
490 *
491 * Returns zero on success; non-zero otherwise
492 */
493 static int
ecryptfs_fill_super(struct super_block * sb,void * raw_data,int silent)494 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
495 {
496 int rc = 0;
497
498 /* Released in ecryptfs_put_super() */
499 ecryptfs_set_superblock_private(sb,
500 kmem_cache_zalloc(ecryptfs_sb_info_cache,
501 GFP_KERNEL));
502 if (!ecryptfs_superblock_to_private(sb)) {
503 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
504 rc = -ENOMEM;
505 goto out;
506 }
507 sb->s_op = &ecryptfs_sops;
508 /* Released through deactivate_super(sb) from get_sb_nodev */
509 sb->s_root = d_alloc(NULL, &(const struct qstr) {
510 .hash = 0,.name = "/",.len = 1});
511 if (!sb->s_root) {
512 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
513 rc = -ENOMEM;
514 goto out;
515 }
516 sb->s_root->d_op = &ecryptfs_dops;
517 sb->s_root->d_sb = sb;
518 sb->s_root->d_parent = sb->s_root;
519 /* Released in d_release when dput(sb->s_root) is called */
520 /* through deactivate_super(sb) from get_sb_nodev() */
521 ecryptfs_set_dentry_private(sb->s_root,
522 kmem_cache_zalloc(ecryptfs_dentry_info_cache,
523 GFP_KERNEL));
524 if (!ecryptfs_dentry_to_private(sb->s_root)) {
525 ecryptfs_printk(KERN_ERR,
526 "dentry_info_cache alloc failed\n");
527 rc = -ENOMEM;
528 goto out;
529 }
530 rc = 0;
531 out:
532 /* Should be able to rely on deactivate_super called from
533 * get_sb_nodev */
534 return rc;
535 }
536
537 /**
538 * ecryptfs_read_super
539 * @sb: The ecryptfs super block
540 * @dev_name: The path to mount over
541 *
542 * Read the super block of the lower filesystem, and use
543 * ecryptfs_interpose to create our initial inode and super block
544 * struct.
545 */
ecryptfs_read_super(struct super_block * sb,const char * dev_name)546 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
547 {
548 struct path path;
549 int rc;
550
551 rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
552 if (rc) {
553 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
554 goto out;
555 }
556 ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
557 sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
558 sb->s_blocksize = path.dentry->d_sb->s_blocksize;
559 ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
560 ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
561 rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
562 if (rc)
563 goto out_free;
564 rc = 0;
565 goto out;
566 out_free:
567 path_put(&path);
568 out:
569 return rc;
570 }
571
572 /**
573 * ecryptfs_get_sb
574 * @fs_type
575 * @flags
576 * @dev_name: The path to mount over
577 * @raw_data: The options passed into the kernel
578 *
579 * The whole ecryptfs_get_sb process is broken into 4 functions:
580 * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
581 * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
582 * with as much information as it can before needing
583 * the lower filesystem.
584 * ecryptfs_read_super(): this accesses the lower filesystem and uses
585 * ecryptfs_interpolate to perform most of the linking
586 * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
587 */
ecryptfs_get_sb(struct file_system_type * fs_type,int flags,const char * dev_name,void * raw_data,struct vfsmount * mnt)588 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
589 const char *dev_name, void *raw_data,
590 struct vfsmount *mnt)
591 {
592 int rc;
593 struct super_block *sb;
594
595 rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
596 if (rc < 0) {
597 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
598 goto out;
599 }
600 sb = mnt->mnt_sb;
601 rc = ecryptfs_parse_options(sb, raw_data);
602 if (rc) {
603 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
604 goto out_abort;
605 }
606 rc = ecryptfs_read_super(sb, dev_name);
607 if (rc) {
608 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
609 goto out_abort;
610 }
611 goto out;
612 out_abort:
613 dput(sb->s_root);
614 up_write(&sb->s_umount);
615 deactivate_super(sb);
616 out:
617 return rc;
618 }
619
620 /**
621 * ecryptfs_kill_block_super
622 * @sb: The ecryptfs super block
623 *
624 * Used to bring the superblock down and free the private data.
625 * Private data is free'd in ecryptfs_put_super()
626 */
ecryptfs_kill_block_super(struct super_block * sb)627 static void ecryptfs_kill_block_super(struct super_block *sb)
628 {
629 generic_shutdown_super(sb);
630 }
631
632 static struct file_system_type ecryptfs_fs_type = {
633 .owner = THIS_MODULE,
634 .name = "ecryptfs",
635 .get_sb = ecryptfs_get_sb,
636 .kill_sb = ecryptfs_kill_block_super,
637 .fs_flags = 0
638 };
639
640 /**
641 * inode_info_init_once
642 *
643 * Initializes the ecryptfs_inode_info_cache when it is created
644 */
645 static void
inode_info_init_once(void * vptr)646 inode_info_init_once(void *vptr)
647 {
648 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
649
650 inode_init_once(&ei->vfs_inode);
651 }
652
653 static struct ecryptfs_cache_info {
654 struct kmem_cache **cache;
655 const char *name;
656 size_t size;
657 void (*ctor)(void *obj);
658 } ecryptfs_cache_infos[] = {
659 {
660 .cache = &ecryptfs_auth_tok_list_item_cache,
661 .name = "ecryptfs_auth_tok_list_item",
662 .size = sizeof(struct ecryptfs_auth_tok_list_item),
663 },
664 {
665 .cache = &ecryptfs_file_info_cache,
666 .name = "ecryptfs_file_cache",
667 .size = sizeof(struct ecryptfs_file_info),
668 },
669 {
670 .cache = &ecryptfs_dentry_info_cache,
671 .name = "ecryptfs_dentry_info_cache",
672 .size = sizeof(struct ecryptfs_dentry_info),
673 },
674 {
675 .cache = &ecryptfs_inode_info_cache,
676 .name = "ecryptfs_inode_cache",
677 .size = sizeof(struct ecryptfs_inode_info),
678 .ctor = inode_info_init_once,
679 },
680 {
681 .cache = &ecryptfs_sb_info_cache,
682 .name = "ecryptfs_sb_cache",
683 .size = sizeof(struct ecryptfs_sb_info),
684 },
685 {
686 .cache = &ecryptfs_header_cache_1,
687 .name = "ecryptfs_headers_1",
688 .size = PAGE_CACHE_SIZE,
689 },
690 {
691 .cache = &ecryptfs_header_cache_2,
692 .name = "ecryptfs_headers_2",
693 .size = PAGE_CACHE_SIZE,
694 },
695 {
696 .cache = &ecryptfs_xattr_cache,
697 .name = "ecryptfs_xattr_cache",
698 .size = PAGE_CACHE_SIZE,
699 },
700 {
701 .cache = &ecryptfs_key_record_cache,
702 .name = "ecryptfs_key_record_cache",
703 .size = sizeof(struct ecryptfs_key_record),
704 },
705 {
706 .cache = &ecryptfs_key_sig_cache,
707 .name = "ecryptfs_key_sig_cache",
708 .size = sizeof(struct ecryptfs_key_sig),
709 },
710 {
711 .cache = &ecryptfs_global_auth_tok_cache,
712 .name = "ecryptfs_global_auth_tok_cache",
713 .size = sizeof(struct ecryptfs_global_auth_tok),
714 },
715 {
716 .cache = &ecryptfs_key_tfm_cache,
717 .name = "ecryptfs_key_tfm_cache",
718 .size = sizeof(struct ecryptfs_key_tfm),
719 },
720 {
721 .cache = &ecryptfs_open_req_cache,
722 .name = "ecryptfs_open_req_cache",
723 .size = sizeof(struct ecryptfs_open_req),
724 },
725 };
726
ecryptfs_free_kmem_caches(void)727 static void ecryptfs_free_kmem_caches(void)
728 {
729 int i;
730
731 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
732 struct ecryptfs_cache_info *info;
733
734 info = &ecryptfs_cache_infos[i];
735 if (*(info->cache))
736 kmem_cache_destroy(*(info->cache));
737 }
738 }
739
740 /**
741 * ecryptfs_init_kmem_caches
742 *
743 * Returns zero on success; non-zero otherwise
744 */
ecryptfs_init_kmem_caches(void)745 static int ecryptfs_init_kmem_caches(void)
746 {
747 int i;
748
749 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
750 struct ecryptfs_cache_info *info;
751
752 info = &ecryptfs_cache_infos[i];
753 *(info->cache) = kmem_cache_create(info->name, info->size,
754 0, SLAB_HWCACHE_ALIGN, info->ctor);
755 if (!*(info->cache)) {
756 ecryptfs_free_kmem_caches();
757 ecryptfs_printk(KERN_WARNING, "%s: "
758 "kmem_cache_create failed\n",
759 info->name);
760 return -ENOMEM;
761 }
762 }
763 return 0;
764 }
765
766 static struct kobject *ecryptfs_kobj;
767
version_show(struct kobject * kobj,struct kobj_attribute * attr,char * buff)768 static ssize_t version_show(struct kobject *kobj,
769 struct kobj_attribute *attr, char *buff)
770 {
771 return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
772 }
773
774 static struct kobj_attribute version_attr = __ATTR_RO(version);
775
776 static struct attribute *attributes[] = {
777 &version_attr.attr,
778 NULL,
779 };
780
781 static struct attribute_group attr_group = {
782 .attrs = attributes,
783 };
784
do_sysfs_registration(void)785 static int do_sysfs_registration(void)
786 {
787 int rc;
788
789 ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
790 if (!ecryptfs_kobj) {
791 printk(KERN_ERR "Unable to create ecryptfs kset\n");
792 rc = -ENOMEM;
793 goto out;
794 }
795 rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
796 if (rc) {
797 printk(KERN_ERR
798 "Unable to create ecryptfs version attributes\n");
799 kobject_put(ecryptfs_kobj);
800 }
801 out:
802 return rc;
803 }
804
do_sysfs_unregistration(void)805 static void do_sysfs_unregistration(void)
806 {
807 sysfs_remove_group(ecryptfs_kobj, &attr_group);
808 kobject_put(ecryptfs_kobj);
809 }
810
ecryptfs_init(void)811 static int __init ecryptfs_init(void)
812 {
813 int rc;
814
815 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
816 rc = -EINVAL;
817 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
818 "larger than the host's page size, and so "
819 "eCryptfs cannot run on this system. The "
820 "default eCryptfs extent size is [%d] bytes; "
821 "the page size is [%d] bytes.\n",
822 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
823 goto out;
824 }
825 rc = ecryptfs_init_kmem_caches();
826 if (rc) {
827 printk(KERN_ERR
828 "Failed to allocate one or more kmem_cache objects\n");
829 goto out;
830 }
831 rc = register_filesystem(&ecryptfs_fs_type);
832 if (rc) {
833 printk(KERN_ERR "Failed to register filesystem\n");
834 goto out_free_kmem_caches;
835 }
836 rc = do_sysfs_registration();
837 if (rc) {
838 printk(KERN_ERR "sysfs registration failed\n");
839 goto out_unregister_filesystem;
840 }
841 rc = ecryptfs_init_kthread();
842 if (rc) {
843 printk(KERN_ERR "%s: kthread initialization failed; "
844 "rc = [%d]\n", __func__, rc);
845 goto out_do_sysfs_unregistration;
846 }
847 rc = ecryptfs_init_messaging();
848 if (rc) {
849 printk(KERN_ERR "Failure occured while attempting to "
850 "initialize the communications channel to "
851 "ecryptfsd\n");
852 goto out_destroy_kthread;
853 }
854 rc = ecryptfs_init_crypto();
855 if (rc) {
856 printk(KERN_ERR "Failure whilst attempting to init crypto; "
857 "rc = [%d]\n", rc);
858 goto out_release_messaging;
859 }
860 if (ecryptfs_verbosity > 0)
861 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
862 "will be written to the syslog!\n", ecryptfs_verbosity);
863
864 goto out;
865 out_release_messaging:
866 ecryptfs_release_messaging();
867 out_destroy_kthread:
868 ecryptfs_destroy_kthread();
869 out_do_sysfs_unregistration:
870 do_sysfs_unregistration();
871 out_unregister_filesystem:
872 unregister_filesystem(&ecryptfs_fs_type);
873 out_free_kmem_caches:
874 ecryptfs_free_kmem_caches();
875 out:
876 return rc;
877 }
878
ecryptfs_exit(void)879 static void __exit ecryptfs_exit(void)
880 {
881 int rc;
882
883 rc = ecryptfs_destroy_crypto();
884 if (rc)
885 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
886 "rc = [%d]\n", rc);
887 ecryptfs_release_messaging();
888 ecryptfs_destroy_kthread();
889 do_sysfs_unregistration();
890 unregister_filesystem(&ecryptfs_fs_type);
891 ecryptfs_free_kmem_caches();
892 }
893
894 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
895 MODULE_DESCRIPTION("eCryptfs");
896
897 MODULE_LICENSE("GPL");
898
899 module_init(ecryptfs_init)
900 module_exit(ecryptfs_exit)
901