xref: /openbmc/linux/fs/ecryptfs/main.c (revision 9d56dd3b083a3bec56e9da35ce07baca81030b03)
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 
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  */
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) {
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 			inode_info->lower_file = NULL;
137 		}
138 	}
139 	mutex_unlock(&inode_info->lower_file_mutex);
140 	return rc;
141 }
142 
143 /**
144  * ecryptfs_interpose
145  * @lower_dentry: Existing dentry in the lower filesystem
146  * @dentry: ecryptfs' dentry
147  * @sb: ecryptfs's super_block
148  * @flags: flags to govern behavior of interpose procedure
149  *
150  * Interposes upper and lower dentries.
151  *
152  * Returns zero on success; non-zero otherwise
153  */
154 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
155 		       struct super_block *sb, u32 flags)
156 {
157 	struct inode *lower_inode;
158 	struct inode *inode;
159 	int rc = 0;
160 
161 	lower_inode = lower_dentry->d_inode;
162 	if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
163 		rc = -EXDEV;
164 		goto out;
165 	}
166 	if (!igrab(lower_inode)) {
167 		rc = -ESTALE;
168 		goto out;
169 	}
170 	inode = iget5_locked(sb, (unsigned long)lower_inode,
171 			     ecryptfs_inode_test, ecryptfs_inode_set,
172 			     lower_inode);
173 	if (!inode) {
174 		rc = -EACCES;
175 		iput(lower_inode);
176 		goto out;
177 	}
178 	if (inode->i_state & I_NEW)
179 		unlock_new_inode(inode);
180 	else
181 		iput(lower_inode);
182 	if (S_ISLNK(lower_inode->i_mode))
183 		inode->i_op = &ecryptfs_symlink_iops;
184 	else if (S_ISDIR(lower_inode->i_mode))
185 		inode->i_op = &ecryptfs_dir_iops;
186 	if (S_ISDIR(lower_inode->i_mode))
187 		inode->i_fop = &ecryptfs_dir_fops;
188 	if (special_file(lower_inode->i_mode))
189 		init_special_inode(inode, lower_inode->i_mode,
190 				   lower_inode->i_rdev);
191 	dentry->d_op = &ecryptfs_dops;
192 	fsstack_copy_attr_all(inode, lower_inode);
193 	/* This size will be overwritten for real files w/ headers and
194 	 * other metadata */
195 	fsstack_copy_inode_size(inode, lower_inode);
196 	if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
197 		d_add(dentry, inode);
198 	else
199 		d_instantiate(dentry, inode);
200 out:
201 	return rc;
202 }
203 
204 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
205        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
206        ecryptfs_opt_ecryptfs_key_bytes,
207        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
208        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
209        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
210        ecryptfs_opt_unlink_sigs, ecryptfs_opt_err };
211 
212 static const match_table_t tokens = {
213 	{ecryptfs_opt_sig, "sig=%s"},
214 	{ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
215 	{ecryptfs_opt_cipher, "cipher=%s"},
216 	{ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
217 	{ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
218 	{ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
219 	{ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
220 	{ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
221 	{ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
222 	{ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
223 	{ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
224 	{ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
225 	{ecryptfs_opt_err, NULL}
226 };
227 
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 
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  */
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_unlink_sigs:
406 			mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
407 			break;
408 		case ecryptfs_opt_err:
409 		default:
410 			printk(KERN_WARNING
411 			       "%s: eCryptfs: unrecognized option [%s]\n",
412 			       __func__, p);
413 		}
414 	}
415 	if (!sig_set) {
416 		rc = -EINVAL;
417 		ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
418 				"auth tok signature as a mount "
419 				"parameter; see the eCryptfs README\n");
420 		goto out;
421 	}
422 	if (!cipher_name_set) {
423 		int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
424 
425 		BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
426 		strcpy(mount_crypt_stat->global_default_cipher_name,
427 		       ECRYPTFS_DEFAULT_CIPHER);
428 	}
429 	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
430 	    && !fn_cipher_name_set)
431 		strcpy(mount_crypt_stat->global_default_fn_cipher_name,
432 		       mount_crypt_stat->global_default_cipher_name);
433 	if (!cipher_key_bytes_set)
434 		mount_crypt_stat->global_default_cipher_key_size = 0;
435 	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
436 	    && !fn_cipher_key_bytes_set)
437 		mount_crypt_stat->global_default_fn_cipher_key_bytes =
438 			mount_crypt_stat->global_default_cipher_key_size;
439 	mutex_lock(&key_tfm_list_mutex);
440 	if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
441 				 NULL)) {
442 		rc = ecryptfs_add_new_key_tfm(
443 			NULL, mount_crypt_stat->global_default_cipher_name,
444 			mount_crypt_stat->global_default_cipher_key_size);
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_cipher_name,
450 			       mount_crypt_stat->global_default_cipher_key_size,
451 			       rc);
452 			rc = -EINVAL;
453 			mutex_unlock(&key_tfm_list_mutex);
454 			goto out;
455 		}
456 	}
457 	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
458 	    && !ecryptfs_tfm_exists(
459 		    mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
460 		rc = ecryptfs_add_new_key_tfm(
461 			NULL, mount_crypt_stat->global_default_fn_cipher_name,
462 			mount_crypt_stat->global_default_fn_cipher_key_bytes);
463 		if (rc) {
464 			printk(KERN_ERR "Error attempting to initialize "
465 			       "cipher with name = [%s] and key size = [%td]; "
466 			       "rc = [%d]\n",
467 			       mount_crypt_stat->global_default_fn_cipher_name,
468 			       mount_crypt_stat->global_default_fn_cipher_key_bytes,
469 			       rc);
470 			rc = -EINVAL;
471 			mutex_unlock(&key_tfm_list_mutex);
472 			goto out;
473 		}
474 	}
475 	mutex_unlock(&key_tfm_list_mutex);
476 	rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
477 	if (rc)
478 		printk(KERN_WARNING "One or more global auth toks could not "
479 		       "properly register; rc = [%d]\n", rc);
480 out:
481 	return rc;
482 }
483 
484 struct kmem_cache *ecryptfs_sb_info_cache;
485 
486 /**
487  * ecryptfs_fill_super
488  * @sb: The ecryptfs super block
489  * @raw_data: The options passed to mount
490  * @silent: Not used but required by function prototype
491  *
492  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
493  *
494  * Returns zero on success; non-zero otherwise
495  */
496 static int
497 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
498 {
499 	int rc = 0;
500 
501 	/* Released in ecryptfs_put_super() */
502 	ecryptfs_set_superblock_private(sb,
503 					kmem_cache_zalloc(ecryptfs_sb_info_cache,
504 							 GFP_KERNEL));
505 	if (!ecryptfs_superblock_to_private(sb)) {
506 		ecryptfs_printk(KERN_WARNING, "Out of memory\n");
507 		rc = -ENOMEM;
508 		goto out;
509 	}
510 	sb->s_op = &ecryptfs_sops;
511 	/* Released through deactivate_super(sb) from get_sb_nodev */
512 	sb->s_root = d_alloc(NULL, &(const struct qstr) {
513 			     .hash = 0,.name = "/",.len = 1});
514 	if (!sb->s_root) {
515 		ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
516 		rc = -ENOMEM;
517 		goto out;
518 	}
519 	sb->s_root->d_op = &ecryptfs_dops;
520 	sb->s_root->d_sb = sb;
521 	sb->s_root->d_parent = sb->s_root;
522 	/* Released in d_release when dput(sb->s_root) is called */
523 	/* through deactivate_super(sb) from get_sb_nodev() */
524 	ecryptfs_set_dentry_private(sb->s_root,
525 				    kmem_cache_zalloc(ecryptfs_dentry_info_cache,
526 						     GFP_KERNEL));
527 	if (!ecryptfs_dentry_to_private(sb->s_root)) {
528 		ecryptfs_printk(KERN_ERR,
529 				"dentry_info_cache alloc failed\n");
530 		rc = -ENOMEM;
531 		goto out;
532 	}
533 	rc = 0;
534 out:
535 	/* Should be able to rely on deactivate_super called from
536 	 * get_sb_nodev */
537 	return rc;
538 }
539 
540 /**
541  * ecryptfs_read_super
542  * @sb: The ecryptfs super block
543  * @dev_name: The path to mount over
544  *
545  * Read the super block of the lower filesystem, and use
546  * ecryptfs_interpose to create our initial inode and super block
547  * struct.
548  */
549 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
550 {
551 	struct path path;
552 	int rc;
553 
554 	rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
555 	if (rc) {
556 		ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
557 		goto out;
558 	}
559 	ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
560 	sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
561 	sb->s_blocksize = path.dentry->d_sb->s_blocksize;
562 	ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
563 	ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
564 	rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
565 	if (rc)
566 		goto out_free;
567 	rc = 0;
568 	goto out;
569 out_free:
570 	path_put(&path);
571 out:
572 	return rc;
573 }
574 
575 /**
576  * ecryptfs_get_sb
577  * @fs_type
578  * @flags
579  * @dev_name: The path to mount over
580  * @raw_data: The options passed into the kernel
581  *
582  * The whole ecryptfs_get_sb process is broken into 4 functions:
583  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
584  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
585  *                        with as much information as it can before needing
586  *                        the lower filesystem.
587  * ecryptfs_read_super(): this accesses the lower filesystem and uses
588  *                        ecryptfs_interpolate to perform most of the linking
589  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
590  */
591 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
592 			const char *dev_name, void *raw_data,
593 			struct vfsmount *mnt)
594 {
595 	int rc;
596 	struct super_block *sb;
597 
598 	rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
599 	if (rc < 0) {
600 		printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
601 		goto out;
602 	}
603 	sb = mnt->mnt_sb;
604 	rc = ecryptfs_parse_options(sb, raw_data);
605 	if (rc) {
606 		printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
607 		goto out_abort;
608 	}
609 	rc = ecryptfs_read_super(sb, dev_name);
610 	if (rc) {
611 		printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
612 		goto out_abort;
613 	}
614 	goto out;
615 out_abort:
616 	dput(sb->s_root); /* aka mnt->mnt_root, as set by get_sb_nodev() */
617 	deactivate_locked_super(sb);
618 out:
619 	return rc;
620 }
621 
622 /**
623  * ecryptfs_kill_block_super
624  * @sb: The ecryptfs super block
625  *
626  * Used to bring the superblock down and free the private data.
627  * Private data is free'd in ecryptfs_put_super()
628  */
629 static void ecryptfs_kill_block_super(struct super_block *sb)
630 {
631 	generic_shutdown_super(sb);
632 }
633 
634 static struct file_system_type ecryptfs_fs_type = {
635 	.owner = THIS_MODULE,
636 	.name = "ecryptfs",
637 	.get_sb = ecryptfs_get_sb,
638 	.kill_sb = ecryptfs_kill_block_super,
639 	.fs_flags = 0
640 };
641 
642 /**
643  * inode_info_init_once
644  *
645  * Initializes the ecryptfs_inode_info_cache when it is created
646  */
647 static void
648 inode_info_init_once(void *vptr)
649 {
650 	struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
651 
652 	inode_init_once(&ei->vfs_inode);
653 }
654 
655 static struct ecryptfs_cache_info {
656 	struct kmem_cache **cache;
657 	const char *name;
658 	size_t size;
659 	void (*ctor)(void *obj);
660 } ecryptfs_cache_infos[] = {
661 	{
662 		.cache = &ecryptfs_auth_tok_list_item_cache,
663 		.name = "ecryptfs_auth_tok_list_item",
664 		.size = sizeof(struct ecryptfs_auth_tok_list_item),
665 	},
666 	{
667 		.cache = &ecryptfs_file_info_cache,
668 		.name = "ecryptfs_file_cache",
669 		.size = sizeof(struct ecryptfs_file_info),
670 	},
671 	{
672 		.cache = &ecryptfs_dentry_info_cache,
673 		.name = "ecryptfs_dentry_info_cache",
674 		.size = sizeof(struct ecryptfs_dentry_info),
675 	},
676 	{
677 		.cache = &ecryptfs_inode_info_cache,
678 		.name = "ecryptfs_inode_cache",
679 		.size = sizeof(struct ecryptfs_inode_info),
680 		.ctor = inode_info_init_once,
681 	},
682 	{
683 		.cache = &ecryptfs_sb_info_cache,
684 		.name = "ecryptfs_sb_cache",
685 		.size = sizeof(struct ecryptfs_sb_info),
686 	},
687 	{
688 		.cache = &ecryptfs_header_cache_1,
689 		.name = "ecryptfs_headers_1",
690 		.size = PAGE_CACHE_SIZE,
691 	},
692 	{
693 		.cache = &ecryptfs_header_cache_2,
694 		.name = "ecryptfs_headers_2",
695 		.size = PAGE_CACHE_SIZE,
696 	},
697 	{
698 		.cache = &ecryptfs_xattr_cache,
699 		.name = "ecryptfs_xattr_cache",
700 		.size = PAGE_CACHE_SIZE,
701 	},
702 	{
703 		.cache = &ecryptfs_key_record_cache,
704 		.name = "ecryptfs_key_record_cache",
705 		.size = sizeof(struct ecryptfs_key_record),
706 	},
707 	{
708 		.cache = &ecryptfs_key_sig_cache,
709 		.name = "ecryptfs_key_sig_cache",
710 		.size = sizeof(struct ecryptfs_key_sig),
711 	},
712 	{
713 		.cache = &ecryptfs_global_auth_tok_cache,
714 		.name = "ecryptfs_global_auth_tok_cache",
715 		.size = sizeof(struct ecryptfs_global_auth_tok),
716 	},
717 	{
718 		.cache = &ecryptfs_key_tfm_cache,
719 		.name = "ecryptfs_key_tfm_cache",
720 		.size = sizeof(struct ecryptfs_key_tfm),
721 	},
722 	{
723 		.cache = &ecryptfs_open_req_cache,
724 		.name = "ecryptfs_open_req_cache",
725 		.size = sizeof(struct ecryptfs_open_req),
726 	},
727 };
728 
729 static void ecryptfs_free_kmem_caches(void)
730 {
731 	int i;
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 		if (*(info->cache))
738 			kmem_cache_destroy(*(info->cache));
739 	}
740 }
741 
742 /**
743  * ecryptfs_init_kmem_caches
744  *
745  * Returns zero on success; non-zero otherwise
746  */
747 static int ecryptfs_init_kmem_caches(void)
748 {
749 	int i;
750 
751 	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
752 		struct ecryptfs_cache_info *info;
753 
754 		info = &ecryptfs_cache_infos[i];
755 		*(info->cache) = kmem_cache_create(info->name, info->size,
756 				0, SLAB_HWCACHE_ALIGN, info->ctor);
757 		if (!*(info->cache)) {
758 			ecryptfs_free_kmem_caches();
759 			ecryptfs_printk(KERN_WARNING, "%s: "
760 					"kmem_cache_create failed\n",
761 					info->name);
762 			return -ENOMEM;
763 		}
764 	}
765 	return 0;
766 }
767 
768 static struct kobject *ecryptfs_kobj;
769 
770 static ssize_t version_show(struct kobject *kobj,
771 			    struct kobj_attribute *attr, char *buff)
772 {
773 	return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
774 }
775 
776 static struct kobj_attribute version_attr = __ATTR_RO(version);
777 
778 static struct attribute *attributes[] = {
779 	&version_attr.attr,
780 	NULL,
781 };
782 
783 static struct attribute_group attr_group = {
784 	.attrs = attributes,
785 };
786 
787 static int do_sysfs_registration(void)
788 {
789 	int rc;
790 
791 	ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
792 	if (!ecryptfs_kobj) {
793 		printk(KERN_ERR "Unable to create ecryptfs kset\n");
794 		rc = -ENOMEM;
795 		goto out;
796 	}
797 	rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
798 	if (rc) {
799 		printk(KERN_ERR
800 		       "Unable to create ecryptfs version attributes\n");
801 		kobject_put(ecryptfs_kobj);
802 	}
803 out:
804 	return rc;
805 }
806 
807 static void do_sysfs_unregistration(void)
808 {
809 	sysfs_remove_group(ecryptfs_kobj, &attr_group);
810 	kobject_put(ecryptfs_kobj);
811 }
812 
813 static int __init ecryptfs_init(void)
814 {
815 	int rc;
816 
817 	if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
818 		rc = -EINVAL;
819 		ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
820 				"larger than the host's page size, and so "
821 				"eCryptfs cannot run on this system. The "
822 				"default eCryptfs extent size is [%d] bytes; "
823 				"the page size is [%d] bytes.\n",
824 				ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_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 = register_filesystem(&ecryptfs_fs_type);
834 	if (rc) {
835 		printk(KERN_ERR "Failed to register filesystem\n");
836 		goto out_free_kmem_caches;
837 	}
838 	rc = do_sysfs_registration();
839 	if (rc) {
840 		printk(KERN_ERR "sysfs registration failed\n");
841 		goto out_unregister_filesystem;
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 occured 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 	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;
867 out_release_messaging:
868 	ecryptfs_release_messaging();
869 out_destroy_kthread:
870 	ecryptfs_destroy_kthread();
871 out_do_sysfs_unregistration:
872 	do_sysfs_unregistration();
873 out_unregister_filesystem:
874 	unregister_filesystem(&ecryptfs_fs_type);
875 out_free_kmem_caches:
876 	ecryptfs_free_kmem_caches();
877 out:
878 	return rc;
879 }
880 
881 static 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 
896 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
897 MODULE_DESCRIPTION("eCryptfs");
898 
899 MODULE_LICENSE("GPL");
900 
901 module_init(ecryptfs_init)
902 module_exit(ecryptfs_exit)
903