xref: /openbmc/linux/fs/ecryptfs/main.c (revision 6774def6)
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_lower_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  * lower file struct and associates it with the eCryptfs
108  * inode. When all eCryptfs files associated with the inode are released, the
109  * file is closed.
110  *
111  * The lower file will be opened with read/write permissions, if
112  * possible. Otherwise, it is opened read-only.
113  *
114  * This function does nothing if a lower file is already
115  * associated with the eCryptfs inode.
116  *
117  * Returns zero on success; non-zero otherwise
118  */
119 static int ecryptfs_init_lower_file(struct dentry *dentry,
120 				    struct file **lower_file)
121 {
122 	const struct cred *cred = current_cred();
123 	struct path *path = ecryptfs_dentry_to_lower_path(dentry);
124 	int rc;
125 
126 	rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
127 				      cred);
128 	if (rc) {
129 		printk(KERN_ERR "Error opening lower file "
130 		       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
131 		       "rc = [%d]\n", path->dentry, path->mnt, rc);
132 		(*lower_file) = NULL;
133 	}
134 	return rc;
135 }
136 
137 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
138 {
139 	struct ecryptfs_inode_info *inode_info;
140 	int count, rc = 0;
141 
142 	inode_info = ecryptfs_inode_to_private(inode);
143 	mutex_lock(&inode_info->lower_file_mutex);
144 	count = atomic_inc_return(&inode_info->lower_file_count);
145 	if (WARN_ON_ONCE(count < 1))
146 		rc = -EINVAL;
147 	else if (count == 1) {
148 		rc = ecryptfs_init_lower_file(dentry,
149 					      &inode_info->lower_file);
150 		if (rc)
151 			atomic_set(&inode_info->lower_file_count, 0);
152 	}
153 	mutex_unlock(&inode_info->lower_file_mutex);
154 	return rc;
155 }
156 
157 void ecryptfs_put_lower_file(struct inode *inode)
158 {
159 	struct ecryptfs_inode_info *inode_info;
160 
161 	inode_info = ecryptfs_inode_to_private(inode);
162 	if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
163 				      &inode_info->lower_file_mutex)) {
164 		filemap_write_and_wait(inode->i_mapping);
165 		fput(inode_info->lower_file);
166 		inode_info->lower_file = NULL;
167 		mutex_unlock(&inode_info->lower_file_mutex);
168 	}
169 }
170 
171 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
172        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
173        ecryptfs_opt_ecryptfs_key_bytes,
174        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
175        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
176        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
177        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
178        ecryptfs_opt_check_dev_ruid,
179        ecryptfs_opt_err };
180 
181 static const match_table_t tokens = {
182 	{ecryptfs_opt_sig, "sig=%s"},
183 	{ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
184 	{ecryptfs_opt_cipher, "cipher=%s"},
185 	{ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
186 	{ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
187 	{ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
188 	{ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
189 	{ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
190 	{ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
191 	{ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
192 	{ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
193 	{ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
194 	{ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
195 	{ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
196 	{ecryptfs_opt_err, NULL}
197 };
198 
199 static int ecryptfs_init_global_auth_toks(
200 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
201 {
202 	struct ecryptfs_global_auth_tok *global_auth_tok;
203 	struct ecryptfs_auth_tok *auth_tok;
204 	int rc = 0;
205 
206 	list_for_each_entry(global_auth_tok,
207 			    &mount_crypt_stat->global_auth_tok_list,
208 			    mount_crypt_stat_list) {
209 		rc = ecryptfs_keyring_auth_tok_for_sig(
210 			&global_auth_tok->global_auth_tok_key, &auth_tok,
211 			global_auth_tok->sig);
212 		if (rc) {
213 			printk(KERN_ERR "Could not find valid key in user "
214 			       "session keyring for sig specified in mount "
215 			       "option: [%s]\n", global_auth_tok->sig);
216 			global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
217 			goto out;
218 		} else {
219 			global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
220 			up_write(&(global_auth_tok->global_auth_tok_key)->sem);
221 		}
222 	}
223 out:
224 	return rc;
225 }
226 
227 static void ecryptfs_init_mount_crypt_stat(
228 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
229 {
230 	memset((void *)mount_crypt_stat, 0,
231 	       sizeof(struct ecryptfs_mount_crypt_stat));
232 	INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
233 	mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
234 	mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
235 }
236 
237 /**
238  * ecryptfs_parse_options
239  * @sb: The ecryptfs super block
240  * @options: The options passed to the kernel
241  * @check_ruid: set to 1 if device uid should be checked against the ruid
242  *
243  * Parse mount options:
244  * debug=N 	   - ecryptfs_verbosity level for debug output
245  * sig=XXX	   - description(signature) of the key to use
246  *
247  * Returns the dentry object of the lower-level (lower/interposed)
248  * directory; We want to mount our stackable file system on top of
249  * that lower directory.
250  *
251  * The signature of the key to use must be the description of a key
252  * already in the keyring. Mounting will fail if the key can not be
253  * found.
254  *
255  * Returns zero on success; non-zero on error
256  */
257 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
258 				  uid_t *check_ruid)
259 {
260 	char *p;
261 	int rc = 0;
262 	int sig_set = 0;
263 	int cipher_name_set = 0;
264 	int fn_cipher_name_set = 0;
265 	int cipher_key_bytes;
266 	int cipher_key_bytes_set = 0;
267 	int fn_cipher_key_bytes;
268 	int fn_cipher_key_bytes_set = 0;
269 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
270 		&sbi->mount_crypt_stat;
271 	substring_t args[MAX_OPT_ARGS];
272 	int token;
273 	char *sig_src;
274 	char *cipher_name_dst;
275 	char *cipher_name_src;
276 	char *fn_cipher_name_dst;
277 	char *fn_cipher_name_src;
278 	char *fnek_dst;
279 	char *fnek_src;
280 	char *cipher_key_bytes_src;
281 	char *fn_cipher_key_bytes_src;
282 	u8 cipher_code;
283 
284 	*check_ruid = 0;
285 
286 	if (!options) {
287 		rc = -EINVAL;
288 		goto out;
289 	}
290 	ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
291 	while ((p = strsep(&options, ",")) != NULL) {
292 		if (!*p)
293 			continue;
294 		token = match_token(p, tokens, args);
295 		switch (token) {
296 		case ecryptfs_opt_sig:
297 		case ecryptfs_opt_ecryptfs_sig:
298 			sig_src = args[0].from;
299 			rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
300 							  sig_src, 0);
301 			if (rc) {
302 				printk(KERN_ERR "Error attempting to register "
303 				       "global sig; rc = [%d]\n", rc);
304 				goto out;
305 			}
306 			sig_set = 1;
307 			break;
308 		case ecryptfs_opt_cipher:
309 		case ecryptfs_opt_ecryptfs_cipher:
310 			cipher_name_src = args[0].from;
311 			cipher_name_dst =
312 				mount_crypt_stat->
313 				global_default_cipher_name;
314 			strncpy(cipher_name_dst, cipher_name_src,
315 				ECRYPTFS_MAX_CIPHER_NAME_SIZE);
316 			cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
317 			cipher_name_set = 1;
318 			break;
319 		case ecryptfs_opt_ecryptfs_key_bytes:
320 			cipher_key_bytes_src = args[0].from;
321 			cipher_key_bytes =
322 				(int)simple_strtol(cipher_key_bytes_src,
323 						   &cipher_key_bytes_src, 0);
324 			mount_crypt_stat->global_default_cipher_key_size =
325 				cipher_key_bytes;
326 			cipher_key_bytes_set = 1;
327 			break;
328 		case ecryptfs_opt_passthrough:
329 			mount_crypt_stat->flags |=
330 				ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
331 			break;
332 		case ecryptfs_opt_xattr_metadata:
333 			mount_crypt_stat->flags |=
334 				ECRYPTFS_XATTR_METADATA_ENABLED;
335 			break;
336 		case ecryptfs_opt_encrypted_view:
337 			mount_crypt_stat->flags |=
338 				ECRYPTFS_XATTR_METADATA_ENABLED;
339 			mount_crypt_stat->flags |=
340 				ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
341 			break;
342 		case ecryptfs_opt_fnek_sig:
343 			fnek_src = args[0].from;
344 			fnek_dst =
345 				mount_crypt_stat->global_default_fnek_sig;
346 			strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
347 			mount_crypt_stat->global_default_fnek_sig[
348 				ECRYPTFS_SIG_SIZE_HEX] = '\0';
349 			rc = ecryptfs_add_global_auth_tok(
350 				mount_crypt_stat,
351 				mount_crypt_stat->global_default_fnek_sig,
352 				ECRYPTFS_AUTH_TOK_FNEK);
353 			if (rc) {
354 				printk(KERN_ERR "Error attempting to register "
355 				       "global fnek sig [%s]; rc = [%d]\n",
356 				       mount_crypt_stat->global_default_fnek_sig,
357 				       rc);
358 				goto out;
359 			}
360 			mount_crypt_stat->flags |=
361 				(ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
362 				 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
363 			break;
364 		case ecryptfs_opt_fn_cipher:
365 			fn_cipher_name_src = args[0].from;
366 			fn_cipher_name_dst =
367 				mount_crypt_stat->global_default_fn_cipher_name;
368 			strncpy(fn_cipher_name_dst, fn_cipher_name_src,
369 				ECRYPTFS_MAX_CIPHER_NAME_SIZE);
370 			mount_crypt_stat->global_default_fn_cipher_name[
371 				ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
372 			fn_cipher_name_set = 1;
373 			break;
374 		case ecryptfs_opt_fn_cipher_key_bytes:
375 			fn_cipher_key_bytes_src = args[0].from;
376 			fn_cipher_key_bytes =
377 				(int)simple_strtol(fn_cipher_key_bytes_src,
378 						   &fn_cipher_key_bytes_src, 0);
379 			mount_crypt_stat->global_default_fn_cipher_key_bytes =
380 				fn_cipher_key_bytes;
381 			fn_cipher_key_bytes_set = 1;
382 			break;
383 		case ecryptfs_opt_unlink_sigs:
384 			mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
385 			break;
386 		case ecryptfs_opt_mount_auth_tok_only:
387 			mount_crypt_stat->flags |=
388 				ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
389 			break;
390 		case ecryptfs_opt_check_dev_ruid:
391 			*check_ruid = 1;
392 			break;
393 		case ecryptfs_opt_err:
394 		default:
395 			printk(KERN_WARNING
396 			       "%s: eCryptfs: unrecognized option [%s]\n",
397 			       __func__, p);
398 		}
399 	}
400 	if (!sig_set) {
401 		rc = -EINVAL;
402 		ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
403 				"auth tok signature as a mount "
404 				"parameter; see the eCryptfs README\n");
405 		goto out;
406 	}
407 	if (!cipher_name_set) {
408 		int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
409 
410 		BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
411 		strcpy(mount_crypt_stat->global_default_cipher_name,
412 		       ECRYPTFS_DEFAULT_CIPHER);
413 	}
414 	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
415 	    && !fn_cipher_name_set)
416 		strcpy(mount_crypt_stat->global_default_fn_cipher_name,
417 		       mount_crypt_stat->global_default_cipher_name);
418 	if (!cipher_key_bytes_set)
419 		mount_crypt_stat->global_default_cipher_key_size = 0;
420 	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
421 	    && !fn_cipher_key_bytes_set)
422 		mount_crypt_stat->global_default_fn_cipher_key_bytes =
423 			mount_crypt_stat->global_default_cipher_key_size;
424 
425 	cipher_code = ecryptfs_code_for_cipher_string(
426 		mount_crypt_stat->global_default_cipher_name,
427 		mount_crypt_stat->global_default_cipher_key_size);
428 	if (!cipher_code) {
429 		ecryptfs_printk(KERN_ERR,
430 				"eCryptfs doesn't support cipher: %s",
431 				mount_crypt_stat->global_default_cipher_name);
432 		rc = -EINVAL;
433 		goto out;
434 	}
435 
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 static struct file_system_type ecryptfs_fs_type;
483 
484 /**
485  * ecryptfs_get_sb
486  * @fs_type
487  * @flags
488  * @dev_name: The path to mount over
489  * @raw_data: The options passed into the kernel
490  */
491 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
492 			const char *dev_name, void *raw_data)
493 {
494 	struct super_block *s;
495 	struct ecryptfs_sb_info *sbi;
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 
515 	s = sget(fs_type, NULL, set_anon_super, flags, NULL);
516 	if (IS_ERR(s)) {
517 		rc = PTR_ERR(s);
518 		goto out;
519 	}
520 
521 	rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
522 	if (rc)
523 		goto out1;
524 
525 	ecryptfs_set_superblock_private(s, sbi);
526 	s->s_bdi = &sbi->bdi;
527 
528 	/* ->kill_sb() will take care of sbi after that point */
529 	sbi = NULL;
530 	s->s_op = &ecryptfs_sops;
531 	s->s_d_op = &ecryptfs_dops;
532 
533 	err = "Reading sb failed";
534 	rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
535 	if (rc) {
536 		ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
537 		goto out1;
538 	}
539 	if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
540 		rc = -EINVAL;
541 		printk(KERN_ERR "Mount on filesystem of type "
542 			"eCryptfs explicitly disallowed due to "
543 			"known incompatibilities\n");
544 		goto out_free;
545 	}
546 
547 	if (check_ruid && !uid_eq(path.dentry->d_inode->i_uid, current_uid())) {
548 		rc = -EPERM;
549 		printk(KERN_ERR "Mount of device (uid: %d) not owned by "
550 		       "requested user (uid: %d)\n",
551 			i_uid_read(path.dentry->d_inode),
552 			from_kuid(&init_user_ns, current_uid()));
553 		goto out_free;
554 	}
555 
556 	ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
557 
558 	/**
559 	 * Set the POSIX ACL flag based on whether they're enabled in the lower
560 	 * mount. Force a read-only eCryptfs mount if the lower mount is ro.
561 	 * Allow a ro eCryptfs mount even when the lower mount is rw.
562 	 */
563 	s->s_flags = flags & ~MS_POSIXACL;
564 	s->s_flags |= path.dentry->d_sb->s_flags & (MS_RDONLY | MS_POSIXACL);
565 
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 	s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
570 
571 	rc = -EINVAL;
572 	if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
573 		pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
574 		goto out_free;
575 	}
576 
577 	inode = ecryptfs_get_inode(path.dentry->d_inode, s);
578 	rc = PTR_ERR(inode);
579 	if (IS_ERR(inode))
580 		goto out_free;
581 
582 	s->s_root = d_make_root(inode);
583 	if (!s->s_root) {
584 		rc = -ENOMEM;
585 		goto out_free;
586 	}
587 
588 	rc = -ENOMEM;
589 	root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
590 	if (!root_info)
591 		goto out_free;
592 
593 	/* ->kill_sb() will take care of root_info */
594 	ecryptfs_set_dentry_private(s->s_root, root_info);
595 	root_info->lower_path = path;
596 
597 	s->s_flags |= MS_ACTIVE;
598 	return dget(s->s_root);
599 
600 out_free:
601 	path_put(&path);
602 out1:
603 	deactivate_locked_super(s);
604 out:
605 	if (sbi) {
606 		ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
607 		kmem_cache_free(ecryptfs_sb_info_cache, sbi);
608 	}
609 	printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
610 	return ERR_PTR(rc);
611 }
612 
613 /**
614  * ecryptfs_kill_block_super
615  * @sb: The ecryptfs super block
616  *
617  * Used to bring the superblock down and free the private data.
618  */
619 static void ecryptfs_kill_block_super(struct super_block *sb)
620 {
621 	struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
622 	kill_anon_super(sb);
623 	if (!sb_info)
624 		return;
625 	ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
626 	bdi_destroy(&sb_info->bdi);
627 	kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
628 }
629 
630 static struct file_system_type ecryptfs_fs_type = {
631 	.owner = THIS_MODULE,
632 	.name = "ecryptfs",
633 	.mount = ecryptfs_mount,
634 	.kill_sb = ecryptfs_kill_block_super,
635 	.fs_flags = 0
636 };
637 MODULE_ALIAS_FS("ecryptfs");
638 
639 /**
640  * inode_info_init_once
641  *
642  * Initializes the ecryptfs_inode_info_cache when it is created
643  */
644 static void
645 inode_info_init_once(void *vptr)
646 {
647 	struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
648 
649 	inode_init_once(&ei->vfs_inode);
650 }
651 
652 static struct ecryptfs_cache_info {
653 	struct kmem_cache **cache;
654 	const char *name;
655 	size_t size;
656 	void (*ctor)(void *obj);
657 } ecryptfs_cache_infos[] = {
658 	{
659 		.cache = &ecryptfs_auth_tok_list_item_cache,
660 		.name = "ecryptfs_auth_tok_list_item",
661 		.size = sizeof(struct ecryptfs_auth_tok_list_item),
662 	},
663 	{
664 		.cache = &ecryptfs_file_info_cache,
665 		.name = "ecryptfs_file_cache",
666 		.size = sizeof(struct ecryptfs_file_info),
667 	},
668 	{
669 		.cache = &ecryptfs_dentry_info_cache,
670 		.name = "ecryptfs_dentry_info_cache",
671 		.size = sizeof(struct ecryptfs_dentry_info),
672 	},
673 	{
674 		.cache = &ecryptfs_inode_info_cache,
675 		.name = "ecryptfs_inode_cache",
676 		.size = sizeof(struct ecryptfs_inode_info),
677 		.ctor = inode_info_init_once,
678 	},
679 	{
680 		.cache = &ecryptfs_sb_info_cache,
681 		.name = "ecryptfs_sb_cache",
682 		.size = sizeof(struct ecryptfs_sb_info),
683 	},
684 	{
685 		.cache = &ecryptfs_header_cache,
686 		.name = "ecryptfs_headers",
687 		.size = PAGE_CACHE_SIZE,
688 	},
689 	{
690 		.cache = &ecryptfs_xattr_cache,
691 		.name = "ecryptfs_xattr_cache",
692 		.size = PAGE_CACHE_SIZE,
693 	},
694 	{
695 		.cache = &ecryptfs_key_record_cache,
696 		.name = "ecryptfs_key_record_cache",
697 		.size = sizeof(struct ecryptfs_key_record),
698 	},
699 	{
700 		.cache = &ecryptfs_key_sig_cache,
701 		.name = "ecryptfs_key_sig_cache",
702 		.size = sizeof(struct ecryptfs_key_sig),
703 	},
704 	{
705 		.cache = &ecryptfs_global_auth_tok_cache,
706 		.name = "ecryptfs_global_auth_tok_cache",
707 		.size = sizeof(struct ecryptfs_global_auth_tok),
708 	},
709 	{
710 		.cache = &ecryptfs_key_tfm_cache,
711 		.name = "ecryptfs_key_tfm_cache",
712 		.size = sizeof(struct ecryptfs_key_tfm),
713 	},
714 };
715 
716 static void ecryptfs_free_kmem_caches(void)
717 {
718 	int i;
719 
720 	/*
721 	 * Make sure all delayed rcu free inodes are flushed before we
722 	 * destroy cache.
723 	 */
724 	rcu_barrier();
725 
726 	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
727 		struct ecryptfs_cache_info *info;
728 
729 		info = &ecryptfs_cache_infos[i];
730 		if (*(info->cache))
731 			kmem_cache_destroy(*(info->cache));
732 	}
733 }
734 
735 /**
736  * ecryptfs_init_kmem_caches
737  *
738  * Returns zero on success; non-zero otherwise
739  */
740 static int ecryptfs_init_kmem_caches(void)
741 {
742 	int i;
743 
744 	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
745 		struct ecryptfs_cache_info *info;
746 
747 		info = &ecryptfs_cache_infos[i];
748 		*(info->cache) = kmem_cache_create(info->name, info->size,
749 				0, SLAB_HWCACHE_ALIGN, info->ctor);
750 		if (!*(info->cache)) {
751 			ecryptfs_free_kmem_caches();
752 			ecryptfs_printk(KERN_WARNING, "%s: "
753 					"kmem_cache_create failed\n",
754 					info->name);
755 			return -ENOMEM;
756 		}
757 	}
758 	return 0;
759 }
760 
761 static struct kobject *ecryptfs_kobj;
762 
763 static ssize_t version_show(struct kobject *kobj,
764 			    struct kobj_attribute *attr, char *buff)
765 {
766 	return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
767 }
768 
769 static struct kobj_attribute version_attr = __ATTR_RO(version);
770 
771 static struct attribute *attributes[] = {
772 	&version_attr.attr,
773 	NULL,
774 };
775 
776 static struct attribute_group attr_group = {
777 	.attrs = attributes,
778 };
779 
780 static int do_sysfs_registration(void)
781 {
782 	int rc;
783 
784 	ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
785 	if (!ecryptfs_kobj) {
786 		printk(KERN_ERR "Unable to create ecryptfs kset\n");
787 		rc = -ENOMEM;
788 		goto out;
789 	}
790 	rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
791 	if (rc) {
792 		printk(KERN_ERR
793 		       "Unable to create ecryptfs version attributes\n");
794 		kobject_put(ecryptfs_kobj);
795 	}
796 out:
797 	return rc;
798 }
799 
800 static void do_sysfs_unregistration(void)
801 {
802 	sysfs_remove_group(ecryptfs_kobj, &attr_group);
803 	kobject_put(ecryptfs_kobj);
804 }
805 
806 static int __init ecryptfs_init(void)
807 {
808 	int rc;
809 
810 	if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
811 		rc = -EINVAL;
812 		ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
813 				"larger than the host's page size, and so "
814 				"eCryptfs cannot run on this system. The "
815 				"default eCryptfs extent size is [%u] bytes; "
816 				"the page size is [%lu] bytes.\n",
817 				ECRYPTFS_DEFAULT_EXTENT_SIZE,
818 				(unsigned long)PAGE_CACHE_SIZE);
819 		goto out;
820 	}
821 	rc = ecryptfs_init_kmem_caches();
822 	if (rc) {
823 		printk(KERN_ERR
824 		       "Failed to allocate one or more kmem_cache objects\n");
825 		goto out;
826 	}
827 	rc = do_sysfs_registration();
828 	if (rc) {
829 		printk(KERN_ERR "sysfs registration failed\n");
830 		goto out_free_kmem_caches;
831 	}
832 	rc = ecryptfs_init_kthread();
833 	if (rc) {
834 		printk(KERN_ERR "%s: kthread initialization failed; "
835 		       "rc = [%d]\n", __func__, rc);
836 		goto out_do_sysfs_unregistration;
837 	}
838 	rc = ecryptfs_init_messaging();
839 	if (rc) {
840 		printk(KERN_ERR "Failure occurred while attempting to "
841 				"initialize the communications channel to "
842 				"ecryptfsd\n");
843 		goto out_destroy_kthread;
844 	}
845 	rc = ecryptfs_init_crypto();
846 	if (rc) {
847 		printk(KERN_ERR "Failure whilst attempting to init crypto; "
848 		       "rc = [%d]\n", rc);
849 		goto out_release_messaging;
850 	}
851 	rc = register_filesystem(&ecryptfs_fs_type);
852 	if (rc) {
853 		printk(KERN_ERR "Failed to register filesystem\n");
854 		goto out_destroy_crypto;
855 	}
856 	if (ecryptfs_verbosity > 0)
857 		printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
858 			"will be written to the syslog!\n", ecryptfs_verbosity);
859 
860 	goto out;
861 out_destroy_crypto:
862 	ecryptfs_destroy_crypto();
863 out_release_messaging:
864 	ecryptfs_release_messaging();
865 out_destroy_kthread:
866 	ecryptfs_destroy_kthread();
867 out_do_sysfs_unregistration:
868 	do_sysfs_unregistration();
869 out_free_kmem_caches:
870 	ecryptfs_free_kmem_caches();
871 out:
872 	return rc;
873 }
874 
875 static void __exit ecryptfs_exit(void)
876 {
877 	int rc;
878 
879 	rc = ecryptfs_destroy_crypto();
880 	if (rc)
881 		printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
882 		       "rc = [%d]\n", rc);
883 	ecryptfs_release_messaging();
884 	ecryptfs_destroy_kthread();
885 	do_sysfs_unregistration();
886 	unregister_filesystem(&ecryptfs_fs_type);
887 	ecryptfs_free_kmem_caches();
888 }
889 
890 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
891 MODULE_DESCRIPTION("eCryptfs");
892 
893 MODULE_LICENSE("GPL");
894 
895 module_init(ecryptfs_init)
896 module_exit(ecryptfs_exit)
897