xref: /openbmc/linux/fs/ecryptfs/main.c (revision 4800cd83)
1 /**
2  * eCryptfs: Linux filesystem encryption layer
3  *
4  * Copyright (C) 1997-2003 Erez Zadok
5  * Copyright (C) 2001-2003 Stony Brook University
6  * Copyright (C) 2004-2007 International Business Machines Corp.
7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8  *              Michael C. Thompson <mcthomps@us.ibm.com>
9  *              Tyler Hicks <tyhicks@ou.edu>
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public License as
13  * published by the Free Software Foundation; either version 2 of the
14  * License, or (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful, but
17  * WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19  * General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
24  * 02111-1307, USA.
25  */
26 
27 #include <linux/dcache.h>
28 #include <linux/file.h>
29 #include <linux/module.h>
30 #include <linux/namei.h>
31 #include <linux/skbuff.h>
32 #include <linux/crypto.h>
33 #include <linux/mount.h>
34 #include <linux/pagemap.h>
35 #include <linux/key.h>
36 #include <linux/parser.h>
37 #include <linux/fs_stack.h>
38 #include <linux/slab.h>
39 #include <linux/magic.h>
40 #include "ecryptfs_kernel.h"
41 
42 /**
43  * Module parameter that defines the ecryptfs_verbosity level.
44  */
45 int ecryptfs_verbosity = 0;
46 
47 module_param(ecryptfs_verbosity, int, 0);
48 MODULE_PARM_DESC(ecryptfs_verbosity,
49 		 "Initial verbosity level (0 or 1; defaults to "
50 		 "0, which is Quiet)");
51 
52 /**
53  * Module parameter that defines the number of message buffer elements
54  */
55 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
56 
57 module_param(ecryptfs_message_buf_len, uint, 0);
58 MODULE_PARM_DESC(ecryptfs_message_buf_len,
59 		 "Number of message buffer elements");
60 
61 /**
62  * Module parameter that defines the maximum guaranteed amount of time to wait
63  * for a response from ecryptfsd.  The actual sleep time will be, more than
64  * likely, a small amount greater than this specified value, but only less if
65  * the message successfully arrives.
66  */
67 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
68 
69 module_param(ecryptfs_message_wait_timeout, long, 0);
70 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
71 		 "Maximum number of seconds that an operation will "
72 		 "sleep while waiting for a message response from "
73 		 "userspace");
74 
75 /**
76  * Module parameter that is an estimate of the maximum number of users
77  * that will be concurrently using eCryptfs. Set this to the right
78  * value to balance performance and memory use.
79  */
80 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
81 
82 module_param(ecryptfs_number_of_users, uint, 0);
83 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
84 		 "concurrent users of eCryptfs");
85 
86 void __ecryptfs_printk(const char *fmt, ...)
87 {
88 	va_list args;
89 	va_start(args, fmt);
90 	if (fmt[1] == '7') { /* KERN_DEBUG */
91 		if (ecryptfs_verbosity >= 1)
92 			vprintk(fmt, args);
93 	} else
94 		vprintk(fmt, args);
95 	va_end(args);
96 }
97 
98 /**
99  * ecryptfs_init_persistent_file
100  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
101  *                   the lower dentry and the lower mount set
102  *
103  * eCryptfs only ever keeps a single open file for every lower
104  * inode. All I/O operations to the lower inode occur through that
105  * file. When the first eCryptfs dentry that interposes with the first
106  * lower dentry for that inode is created, this function creates the
107  * persistent file struct and associates it with the eCryptfs
108  * inode. When the eCryptfs inode is destroyed, the file is closed.
109  *
110  * The persistent 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 persistent file is already
114  * associated with the eCryptfs inode.
115  *
116  * Returns zero on success; non-zero otherwise
117  */
118 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
119 {
120 	const struct cred *cred = current_cred();
121 	struct ecryptfs_inode_info *inode_info =
122 		ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
123 	int rc = 0;
124 
125 	mutex_lock(&inode_info->lower_file_mutex);
126 	if (!inode_info->lower_file) {
127 		struct dentry *lower_dentry;
128 		struct vfsmount *lower_mnt =
129 			ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
130 
131 		lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
132 		rc = ecryptfs_privileged_open(&inode_info->lower_file,
133 					      lower_dentry, lower_mnt, cred);
134 		if (rc) {
135 			printk(KERN_ERR "Error opening lower persistent file "
136 			       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
137 			       "rc = [%d]\n", lower_dentry, lower_mnt, rc);
138 			inode_info->lower_file = NULL;
139 		}
140 	}
141 	mutex_unlock(&inode_info->lower_file_mutex);
142 	return rc;
143 }
144 
145 static struct inode *ecryptfs_get_inode(struct inode *lower_inode,
146 		       struct super_block *sb)
147 {
148 	struct inode *inode;
149 	int rc = 0;
150 
151 	if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
152 		rc = -EXDEV;
153 		goto out;
154 	}
155 	if (!igrab(lower_inode)) {
156 		rc = -ESTALE;
157 		goto out;
158 	}
159 	inode = iget5_locked(sb, (unsigned long)lower_inode,
160 			     ecryptfs_inode_test, ecryptfs_inode_set,
161 			     lower_inode);
162 	if (!inode) {
163 		rc = -EACCES;
164 		iput(lower_inode);
165 		goto out;
166 	}
167 	if (inode->i_state & I_NEW)
168 		unlock_new_inode(inode);
169 	else
170 		iput(lower_inode);
171 	if (S_ISLNK(lower_inode->i_mode))
172 		inode->i_op = &ecryptfs_symlink_iops;
173 	else if (S_ISDIR(lower_inode->i_mode))
174 		inode->i_op = &ecryptfs_dir_iops;
175 	if (S_ISDIR(lower_inode->i_mode))
176 		inode->i_fop = &ecryptfs_dir_fops;
177 	if (special_file(lower_inode->i_mode))
178 		init_special_inode(inode, lower_inode->i_mode,
179 				   lower_inode->i_rdev);
180 	fsstack_copy_attr_all(inode, lower_inode);
181 	/* This size will be overwritten for real files w/ headers and
182 	 * other metadata */
183 	fsstack_copy_inode_size(inode, lower_inode);
184 	return inode;
185 out:
186 	return ERR_PTR(rc);
187 }
188 
189 /**
190  * ecryptfs_interpose
191  * @lower_dentry: Existing dentry in the lower filesystem
192  * @dentry: ecryptfs' dentry
193  * @sb: ecryptfs's super_block
194  * @flags: flags to govern behavior of interpose procedure
195  *
196  * Interposes upper and lower dentries.
197  *
198  * Returns zero on success; non-zero otherwise
199  */
200 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
201 		       struct super_block *sb, u32 flags)
202 {
203 	struct inode *lower_inode = lower_dentry->d_inode;
204 	struct inode *inode = ecryptfs_get_inode(lower_inode, sb);
205 	if (IS_ERR(inode))
206 		return PTR_ERR(inode);
207 	if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
208 		d_add(dentry, inode);
209 	else
210 		d_instantiate(dentry, inode);
211 	return 0;
212 }
213 
214 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
215        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
216        ecryptfs_opt_ecryptfs_key_bytes,
217        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
218        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
219        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
220        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
221        ecryptfs_opt_err };
222 
223 static const match_table_t tokens = {
224 	{ecryptfs_opt_sig, "sig=%s"},
225 	{ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
226 	{ecryptfs_opt_cipher, "cipher=%s"},
227 	{ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
228 	{ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
229 	{ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
230 	{ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
231 	{ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
232 	{ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
233 	{ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
234 	{ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
235 	{ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
236 	{ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
237 	{ecryptfs_opt_err, NULL}
238 };
239 
240 static int ecryptfs_init_global_auth_toks(
241 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
242 {
243 	struct ecryptfs_global_auth_tok *global_auth_tok;
244 	int rc = 0;
245 
246 	list_for_each_entry(global_auth_tok,
247 			    &mount_crypt_stat->global_auth_tok_list,
248 			    mount_crypt_stat_list) {
249 		rc = ecryptfs_keyring_auth_tok_for_sig(
250 			&global_auth_tok->global_auth_tok_key,
251 			&global_auth_tok->global_auth_tok,
252 			global_auth_tok->sig);
253 		if (rc) {
254 			printk(KERN_ERR "Could not find valid key in user "
255 			       "session keyring for sig specified in mount "
256 			       "option: [%s]\n", global_auth_tok->sig);
257 			global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
258 			goto out;
259 		} else
260 			global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
261 	}
262 out:
263 	return rc;
264 }
265 
266 static void ecryptfs_init_mount_crypt_stat(
267 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
268 {
269 	memset((void *)mount_crypt_stat, 0,
270 	       sizeof(struct ecryptfs_mount_crypt_stat));
271 	INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
272 	mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
273 	mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
274 }
275 
276 /**
277  * ecryptfs_parse_options
278  * @sb: The ecryptfs super block
279  * @options: The options pased to the kernel
280  *
281  * Parse mount options:
282  * debug=N 	   - ecryptfs_verbosity level for debug output
283  * sig=XXX	   - description(signature) of the key to use
284  *
285  * Returns the dentry object of the lower-level (lower/interposed)
286  * directory; We want to mount our stackable file system on top of
287  * that lower directory.
288  *
289  * The signature of the key to use must be the description of a key
290  * already in the keyring. Mounting will fail if the key can not be
291  * found.
292  *
293  * Returns zero on success; non-zero on error
294  */
295 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options)
296 {
297 	char *p;
298 	int rc = 0;
299 	int sig_set = 0;
300 	int cipher_name_set = 0;
301 	int fn_cipher_name_set = 0;
302 	int cipher_key_bytes;
303 	int cipher_key_bytes_set = 0;
304 	int fn_cipher_key_bytes;
305 	int fn_cipher_key_bytes_set = 0;
306 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
307 		&sbi->mount_crypt_stat;
308 	substring_t args[MAX_OPT_ARGS];
309 	int token;
310 	char *sig_src;
311 	char *cipher_name_dst;
312 	char *cipher_name_src;
313 	char *fn_cipher_name_dst;
314 	char *fn_cipher_name_src;
315 	char *fnek_dst;
316 	char *fnek_src;
317 	char *cipher_key_bytes_src;
318 	char *fn_cipher_key_bytes_src;
319 
320 	if (!options) {
321 		rc = -EINVAL;
322 		goto out;
323 	}
324 	ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
325 	while ((p = strsep(&options, ",")) != NULL) {
326 		if (!*p)
327 			continue;
328 		token = match_token(p, tokens, args);
329 		switch (token) {
330 		case ecryptfs_opt_sig:
331 		case ecryptfs_opt_ecryptfs_sig:
332 			sig_src = args[0].from;
333 			rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
334 							  sig_src, 0);
335 			if (rc) {
336 				printk(KERN_ERR "Error attempting to register "
337 				       "global sig; rc = [%d]\n", rc);
338 				goto out;
339 			}
340 			sig_set = 1;
341 			break;
342 		case ecryptfs_opt_cipher:
343 		case ecryptfs_opt_ecryptfs_cipher:
344 			cipher_name_src = args[0].from;
345 			cipher_name_dst =
346 				mount_crypt_stat->
347 				global_default_cipher_name;
348 			strncpy(cipher_name_dst, cipher_name_src,
349 				ECRYPTFS_MAX_CIPHER_NAME_SIZE);
350 			cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
351 			cipher_name_set = 1;
352 			break;
353 		case ecryptfs_opt_ecryptfs_key_bytes:
354 			cipher_key_bytes_src = args[0].from;
355 			cipher_key_bytes =
356 				(int)simple_strtol(cipher_key_bytes_src,
357 						   &cipher_key_bytes_src, 0);
358 			mount_crypt_stat->global_default_cipher_key_size =
359 				cipher_key_bytes;
360 			cipher_key_bytes_set = 1;
361 			break;
362 		case ecryptfs_opt_passthrough:
363 			mount_crypt_stat->flags |=
364 				ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
365 			break;
366 		case ecryptfs_opt_xattr_metadata:
367 			mount_crypt_stat->flags |=
368 				ECRYPTFS_XATTR_METADATA_ENABLED;
369 			break;
370 		case ecryptfs_opt_encrypted_view:
371 			mount_crypt_stat->flags |=
372 				ECRYPTFS_XATTR_METADATA_ENABLED;
373 			mount_crypt_stat->flags |=
374 				ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
375 			break;
376 		case ecryptfs_opt_fnek_sig:
377 			fnek_src = args[0].from;
378 			fnek_dst =
379 				mount_crypt_stat->global_default_fnek_sig;
380 			strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
381 			mount_crypt_stat->global_default_fnek_sig[
382 				ECRYPTFS_SIG_SIZE_HEX] = '\0';
383 			rc = ecryptfs_add_global_auth_tok(
384 				mount_crypt_stat,
385 				mount_crypt_stat->global_default_fnek_sig,
386 				ECRYPTFS_AUTH_TOK_FNEK);
387 			if (rc) {
388 				printk(KERN_ERR "Error attempting to register "
389 				       "global fnek sig [%s]; rc = [%d]\n",
390 				       mount_crypt_stat->global_default_fnek_sig,
391 				       rc);
392 				goto out;
393 			}
394 			mount_crypt_stat->flags |=
395 				(ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
396 				 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
397 			break;
398 		case ecryptfs_opt_fn_cipher:
399 			fn_cipher_name_src = args[0].from;
400 			fn_cipher_name_dst =
401 				mount_crypt_stat->global_default_fn_cipher_name;
402 			strncpy(fn_cipher_name_dst, fn_cipher_name_src,
403 				ECRYPTFS_MAX_CIPHER_NAME_SIZE);
404 			mount_crypt_stat->global_default_fn_cipher_name[
405 				ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
406 			fn_cipher_name_set = 1;
407 			break;
408 		case ecryptfs_opt_fn_cipher_key_bytes:
409 			fn_cipher_key_bytes_src = args[0].from;
410 			fn_cipher_key_bytes =
411 				(int)simple_strtol(fn_cipher_key_bytes_src,
412 						   &fn_cipher_key_bytes_src, 0);
413 			mount_crypt_stat->global_default_fn_cipher_key_bytes =
414 				fn_cipher_key_bytes;
415 			fn_cipher_key_bytes_set = 1;
416 			break;
417 		case ecryptfs_opt_unlink_sigs:
418 			mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
419 			break;
420 		case ecryptfs_opt_mount_auth_tok_only:
421 			mount_crypt_stat->flags |=
422 				ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
423 			break;
424 		case ecryptfs_opt_err:
425 		default:
426 			printk(KERN_WARNING
427 			       "%s: eCryptfs: unrecognized option [%s]\n",
428 			       __func__, p);
429 		}
430 	}
431 	if (!sig_set) {
432 		rc = -EINVAL;
433 		ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
434 				"auth tok signature as a mount "
435 				"parameter; see the eCryptfs README\n");
436 		goto out;
437 	}
438 	if (!cipher_name_set) {
439 		int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
440 
441 		BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
442 		strcpy(mount_crypt_stat->global_default_cipher_name,
443 		       ECRYPTFS_DEFAULT_CIPHER);
444 	}
445 	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
446 	    && !fn_cipher_name_set)
447 		strcpy(mount_crypt_stat->global_default_fn_cipher_name,
448 		       mount_crypt_stat->global_default_cipher_name);
449 	if (!cipher_key_bytes_set)
450 		mount_crypt_stat->global_default_cipher_key_size = 0;
451 	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
452 	    && !fn_cipher_key_bytes_set)
453 		mount_crypt_stat->global_default_fn_cipher_key_bytes =
454 			mount_crypt_stat->global_default_cipher_key_size;
455 	mutex_lock(&key_tfm_list_mutex);
456 	if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
457 				 NULL)) {
458 		rc = ecryptfs_add_new_key_tfm(
459 			NULL, mount_crypt_stat->global_default_cipher_name,
460 			mount_crypt_stat->global_default_cipher_key_size);
461 		if (rc) {
462 			printk(KERN_ERR "Error attempting to initialize "
463 			       "cipher with name = [%s] and key size = [%td]; "
464 			       "rc = [%d]\n",
465 			       mount_crypt_stat->global_default_cipher_name,
466 			       mount_crypt_stat->global_default_cipher_key_size,
467 			       rc);
468 			rc = -EINVAL;
469 			mutex_unlock(&key_tfm_list_mutex);
470 			goto out;
471 		}
472 	}
473 	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
474 	    && !ecryptfs_tfm_exists(
475 		    mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
476 		rc = ecryptfs_add_new_key_tfm(
477 			NULL, mount_crypt_stat->global_default_fn_cipher_name,
478 			mount_crypt_stat->global_default_fn_cipher_key_bytes);
479 		if (rc) {
480 			printk(KERN_ERR "Error attempting to initialize "
481 			       "cipher with name = [%s] and key size = [%td]; "
482 			       "rc = [%d]\n",
483 			       mount_crypt_stat->global_default_fn_cipher_name,
484 			       mount_crypt_stat->global_default_fn_cipher_key_bytes,
485 			       rc);
486 			rc = -EINVAL;
487 			mutex_unlock(&key_tfm_list_mutex);
488 			goto out;
489 		}
490 	}
491 	mutex_unlock(&key_tfm_list_mutex);
492 	rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
493 	if (rc)
494 		printk(KERN_WARNING "One or more global auth toks could not "
495 		       "properly register; rc = [%d]\n", rc);
496 out:
497 	return rc;
498 }
499 
500 struct kmem_cache *ecryptfs_sb_info_cache;
501 static struct file_system_type ecryptfs_fs_type;
502 
503 /**
504  * ecryptfs_get_sb
505  * @fs_type
506  * @flags
507  * @dev_name: The path to mount over
508  * @raw_data: The options passed into the kernel
509  */
510 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
511 			const char *dev_name, void *raw_data)
512 {
513 	struct super_block *s;
514 	struct ecryptfs_sb_info *sbi;
515 	struct ecryptfs_dentry_info *root_info;
516 	const char *err = "Getting sb failed";
517 	struct inode *inode;
518 	struct path path;
519 	int rc;
520 
521 	sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
522 	if (!sbi) {
523 		rc = -ENOMEM;
524 		goto out;
525 	}
526 
527 	rc = ecryptfs_parse_options(sbi, raw_data);
528 	if (rc) {
529 		err = "Error parsing options";
530 		goto out;
531 	}
532 
533 	s = sget(fs_type, NULL, set_anon_super, NULL);
534 	if (IS_ERR(s)) {
535 		rc = PTR_ERR(s);
536 		goto out;
537 	}
538 
539 	s->s_flags = flags;
540 	rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
541 	if (rc)
542 		goto out1;
543 
544 	ecryptfs_set_superblock_private(s, sbi);
545 	s->s_bdi = &sbi->bdi;
546 
547 	/* ->kill_sb() will take care of sbi after that point */
548 	sbi = NULL;
549 	s->s_op = &ecryptfs_sops;
550 	s->s_d_op = &ecryptfs_dops;
551 
552 	err = "Reading sb failed";
553 	rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
554 	if (rc) {
555 		ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
556 		goto out1;
557 	}
558 	if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
559 		rc = -EINVAL;
560 		printk(KERN_ERR "Mount on filesystem of type "
561 			"eCryptfs explicitly disallowed due to "
562 			"known incompatibilities\n");
563 		goto out_free;
564 	}
565 	ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
566 	s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
567 	s->s_blocksize = path.dentry->d_sb->s_blocksize;
568 	s->s_magic = ECRYPTFS_SUPER_MAGIC;
569 
570 	inode = ecryptfs_get_inode(path.dentry->d_inode, s);
571 	rc = PTR_ERR(inode);
572 	if (IS_ERR(inode))
573 		goto out_free;
574 
575 	s->s_root = d_alloc_root(inode);
576 	if (!s->s_root) {
577 		iput(inode);
578 		rc = -ENOMEM;
579 		goto out_free;
580 	}
581 
582 	rc = -ENOMEM;
583 	root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
584 	if (!root_info)
585 		goto out_free;
586 
587 	/* ->kill_sb() will take care of root_info */
588 	ecryptfs_set_dentry_private(s->s_root, root_info);
589 	ecryptfs_set_dentry_lower(s->s_root, path.dentry);
590 	ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
591 
592 	s->s_flags |= MS_ACTIVE;
593 	return dget(s->s_root);
594 
595 out_free:
596 	path_put(&path);
597 out1:
598 	deactivate_locked_super(s);
599 out:
600 	if (sbi) {
601 		ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
602 		kmem_cache_free(ecryptfs_sb_info_cache, sbi);
603 	}
604 	printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
605 	return ERR_PTR(rc);
606 }
607 
608 /**
609  * ecryptfs_kill_block_super
610  * @sb: The ecryptfs super block
611  *
612  * Used to bring the superblock down and free the private data.
613  */
614 static void ecryptfs_kill_block_super(struct super_block *sb)
615 {
616 	struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
617 	kill_anon_super(sb);
618 	if (!sb_info)
619 		return;
620 	ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
621 	bdi_destroy(&sb_info->bdi);
622 	kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
623 }
624 
625 static struct file_system_type ecryptfs_fs_type = {
626 	.owner = THIS_MODULE,
627 	.name = "ecryptfs",
628 	.mount = ecryptfs_mount,
629 	.kill_sb = ecryptfs_kill_block_super,
630 	.fs_flags = 0
631 };
632 
633 /**
634  * inode_info_init_once
635  *
636  * Initializes the ecryptfs_inode_info_cache when it is created
637  */
638 static void
639 inode_info_init_once(void *vptr)
640 {
641 	struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
642 
643 	inode_init_once(&ei->vfs_inode);
644 }
645 
646 static struct ecryptfs_cache_info {
647 	struct kmem_cache **cache;
648 	const char *name;
649 	size_t size;
650 	void (*ctor)(void *obj);
651 } ecryptfs_cache_infos[] = {
652 	{
653 		.cache = &ecryptfs_auth_tok_list_item_cache,
654 		.name = "ecryptfs_auth_tok_list_item",
655 		.size = sizeof(struct ecryptfs_auth_tok_list_item),
656 	},
657 	{
658 		.cache = &ecryptfs_file_info_cache,
659 		.name = "ecryptfs_file_cache",
660 		.size = sizeof(struct ecryptfs_file_info),
661 	},
662 	{
663 		.cache = &ecryptfs_dentry_info_cache,
664 		.name = "ecryptfs_dentry_info_cache",
665 		.size = sizeof(struct ecryptfs_dentry_info),
666 	},
667 	{
668 		.cache = &ecryptfs_inode_info_cache,
669 		.name = "ecryptfs_inode_cache",
670 		.size = sizeof(struct ecryptfs_inode_info),
671 		.ctor = inode_info_init_once,
672 	},
673 	{
674 		.cache = &ecryptfs_sb_info_cache,
675 		.name = "ecryptfs_sb_cache",
676 		.size = sizeof(struct ecryptfs_sb_info),
677 	},
678 	{
679 		.cache = &ecryptfs_header_cache_1,
680 		.name = "ecryptfs_headers_1",
681 		.size = PAGE_CACHE_SIZE,
682 	},
683 	{
684 		.cache = &ecryptfs_header_cache_2,
685 		.name = "ecryptfs_headers_2",
686 		.size = PAGE_CACHE_SIZE,
687 	},
688 	{
689 		.cache = &ecryptfs_xattr_cache,
690 		.name = "ecryptfs_xattr_cache",
691 		.size = PAGE_CACHE_SIZE,
692 	},
693 	{
694 		.cache = &ecryptfs_key_record_cache,
695 		.name = "ecryptfs_key_record_cache",
696 		.size = sizeof(struct ecryptfs_key_record),
697 	},
698 	{
699 		.cache = &ecryptfs_key_sig_cache,
700 		.name = "ecryptfs_key_sig_cache",
701 		.size = sizeof(struct ecryptfs_key_sig),
702 	},
703 	{
704 		.cache = &ecryptfs_global_auth_tok_cache,
705 		.name = "ecryptfs_global_auth_tok_cache",
706 		.size = sizeof(struct ecryptfs_global_auth_tok),
707 	},
708 	{
709 		.cache = &ecryptfs_key_tfm_cache,
710 		.name = "ecryptfs_key_tfm_cache",
711 		.size = sizeof(struct ecryptfs_key_tfm),
712 	},
713 	{
714 		.cache = &ecryptfs_open_req_cache,
715 		.name = "ecryptfs_open_req_cache",
716 		.size = sizeof(struct ecryptfs_open_req),
717 	},
718 };
719 
720 static void ecryptfs_free_kmem_caches(void)
721 {
722 	int i;
723 
724 	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
725 		struct ecryptfs_cache_info *info;
726 
727 		info = &ecryptfs_cache_infos[i];
728 		if (*(info->cache))
729 			kmem_cache_destroy(*(info->cache));
730 	}
731 }
732 
733 /**
734  * ecryptfs_init_kmem_caches
735  *
736  * Returns zero on success; non-zero otherwise
737  */
738 static int ecryptfs_init_kmem_caches(void)
739 {
740 	int i;
741 
742 	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
743 		struct ecryptfs_cache_info *info;
744 
745 		info = &ecryptfs_cache_infos[i];
746 		*(info->cache) = kmem_cache_create(info->name, info->size,
747 				0, SLAB_HWCACHE_ALIGN, info->ctor);
748 		if (!*(info->cache)) {
749 			ecryptfs_free_kmem_caches();
750 			ecryptfs_printk(KERN_WARNING, "%s: "
751 					"kmem_cache_create failed\n",
752 					info->name);
753 			return -ENOMEM;
754 		}
755 	}
756 	return 0;
757 }
758 
759 static struct kobject *ecryptfs_kobj;
760 
761 static ssize_t version_show(struct kobject *kobj,
762 			    struct kobj_attribute *attr, char *buff)
763 {
764 	return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
765 }
766 
767 static struct kobj_attribute version_attr = __ATTR_RO(version);
768 
769 static struct attribute *attributes[] = {
770 	&version_attr.attr,
771 	NULL,
772 };
773 
774 static struct attribute_group attr_group = {
775 	.attrs = attributes,
776 };
777 
778 static int do_sysfs_registration(void)
779 {
780 	int rc;
781 
782 	ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
783 	if (!ecryptfs_kobj) {
784 		printk(KERN_ERR "Unable to create ecryptfs kset\n");
785 		rc = -ENOMEM;
786 		goto out;
787 	}
788 	rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
789 	if (rc) {
790 		printk(KERN_ERR
791 		       "Unable to create ecryptfs version attributes\n");
792 		kobject_put(ecryptfs_kobj);
793 	}
794 out:
795 	return rc;
796 }
797 
798 static void do_sysfs_unregistration(void)
799 {
800 	sysfs_remove_group(ecryptfs_kobj, &attr_group);
801 	kobject_put(ecryptfs_kobj);
802 }
803 
804 static int __init ecryptfs_init(void)
805 {
806 	int rc;
807 
808 	if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
809 		rc = -EINVAL;
810 		ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
811 				"larger than the host's page size, and so "
812 				"eCryptfs cannot run on this system. The "
813 				"default eCryptfs extent size is [%u] bytes; "
814 				"the page size is [%lu] bytes.\n",
815 				ECRYPTFS_DEFAULT_EXTENT_SIZE,
816 				(unsigned long)PAGE_CACHE_SIZE);
817 		goto out;
818 	}
819 	rc = ecryptfs_init_kmem_caches();
820 	if (rc) {
821 		printk(KERN_ERR
822 		       "Failed to allocate one or more kmem_cache objects\n");
823 		goto out;
824 	}
825 	rc = register_filesystem(&ecryptfs_fs_type);
826 	if (rc) {
827 		printk(KERN_ERR "Failed to register filesystem\n");
828 		goto out_free_kmem_caches;
829 	}
830 	rc = do_sysfs_registration();
831 	if (rc) {
832 		printk(KERN_ERR "sysfs registration failed\n");
833 		goto out_unregister_filesystem;
834 	}
835 	rc = ecryptfs_init_kthread();
836 	if (rc) {
837 		printk(KERN_ERR "%s: kthread initialization failed; "
838 		       "rc = [%d]\n", __func__, rc);
839 		goto out_do_sysfs_unregistration;
840 	}
841 	rc = ecryptfs_init_messaging();
842 	if (rc) {
843 		printk(KERN_ERR "Failure occured while attempting to "
844 				"initialize the communications channel to "
845 				"ecryptfsd\n");
846 		goto out_destroy_kthread;
847 	}
848 	rc = ecryptfs_init_crypto();
849 	if (rc) {
850 		printk(KERN_ERR "Failure whilst attempting to init crypto; "
851 		       "rc = [%d]\n", rc);
852 		goto out_release_messaging;
853 	}
854 	if (ecryptfs_verbosity > 0)
855 		printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
856 			"will be written to the syslog!\n", ecryptfs_verbosity);
857 
858 	goto out;
859 out_release_messaging:
860 	ecryptfs_release_messaging();
861 out_destroy_kthread:
862 	ecryptfs_destroy_kthread();
863 out_do_sysfs_unregistration:
864 	do_sysfs_unregistration();
865 out_unregister_filesystem:
866 	unregister_filesystem(&ecryptfs_fs_type);
867 out_free_kmem_caches:
868 	ecryptfs_free_kmem_caches();
869 out:
870 	return rc;
871 }
872 
873 static void __exit ecryptfs_exit(void)
874 {
875 	int rc;
876 
877 	rc = ecryptfs_destroy_crypto();
878 	if (rc)
879 		printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
880 		       "rc = [%d]\n", rc);
881 	ecryptfs_release_messaging();
882 	ecryptfs_destroy_kthread();
883 	do_sysfs_unregistration();
884 	unregister_filesystem(&ecryptfs_fs_type);
885 	ecryptfs_free_kmem_caches();
886 }
887 
888 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
889 MODULE_DESCRIPTION("eCryptfs");
890 
891 MODULE_LICENSE("GPL");
892 
893 module_init(ecryptfs_init)
894 module_exit(ecryptfs_exit)
895