1/**
  2 * eCryptfs: Linux filesystem encryption layer
  3 *
  4 * Copyright (C) 1997-2003 Erez Zadok
  5 * Copyright (C) 2001-2003 Stony Brook University
  6 * Copyright (C) 2004-2007 International Business Machines Corp.
  7 *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  8 *              Michael C. Thompson <mcthomps@us.ibm.com>
  9 *              Tyler Hicks <tyhicks@ou.edu>
 10 *
 11 * This program is free software; you can redistribute it and/or
 12 * modify it under the terms of the GNU General Public License as
 13 * published by the Free Software Foundation; either version 2 of the
 14 * License, or (at your option) any later version.
 15 *
 16 * This program is distributed in the hope that it will be useful, but
 17 * WITHOUT ANY WARRANTY; without even the implied warranty of
 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 19 * General Public License for more details.
 20 *
 21 * You should have received a copy of the GNU General Public License
 22 * along with this program; if not, write to the Free Software
 23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 24 * 02111-1307, USA.
 25 */
 26
 27#include <linux/dcache.h>
 28#include <linux/file.h>
 29#include <linux/module.h>
 30#include <linux/namei.h>
 31#include <linux/skbuff.h>
 32#include <linux/mount.h>
 33#include <linux/pagemap.h>
 34#include <linux/key.h>
 35#include <linux/parser.h>
 36#include <linux/fs_stack.h>
 37#include <linux/slab.h>
 38#include <linux/magic.h>
 39#include "ecryptfs_kernel.h"
 40
 41/**
 42 * Module parameter that defines the ecryptfs_verbosity level.
 43 */
 44int ecryptfs_verbosity = 0;
 45
 46module_param(ecryptfs_verbosity, int, 0);
 47MODULE_PARM_DESC(ecryptfs_verbosity,
 48		 "Initial verbosity level (0 or 1; defaults to "
 49		 "0, which is Quiet)");
 50
 51/**
 52 * Module parameter that defines the number of message buffer elements
 53 */
 54unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
 55
 56module_param(ecryptfs_message_buf_len, uint, 0);
 57MODULE_PARM_DESC(ecryptfs_message_buf_len,
 58		 "Number of message buffer elements");
 59
 60/**
 61 * Module parameter that defines the maximum guaranteed amount of time to wait
 62 * for a response from ecryptfsd.  The actual sleep time will be, more than
 63 * likely, a small amount greater than this specified value, but only less if
 64 * the message successfully arrives.
 65 */
 66signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
 67
 68module_param(ecryptfs_message_wait_timeout, long, 0);
 69MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
 70		 "Maximum number of seconds that an operation will "
 71		 "sleep while waiting for a message response from "
 72		 "userspace");
 73
 74/**
 75 * Module parameter that is an estimate of the maximum number of users
 76 * that will be concurrently using eCryptfs. Set this to the right
 77 * value to balance performance and memory use.
 78 */
 79unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
 80
 81module_param(ecryptfs_number_of_users, uint, 0);
 82MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
 83		 "concurrent users of eCryptfs");
 84
 85void __ecryptfs_printk(const char *fmt, ...)
 86{
 87	va_list args;
 88	va_start(args, fmt);
 89	if (fmt[1] == '7') { /* KERN_DEBUG */
 90		if (ecryptfs_verbosity >= 1)
 91			vprintk(fmt, args);
 92	} else
 93		vprintk(fmt, args);
 94	va_end(args);
 95}
 96
 97/**
 98 * ecryptfs_init_lower_file
 99 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
100 *                   the lower dentry and the lower mount set
101 *
102 * eCryptfs only ever keeps a single open file for every lower
103 * inode. All I/O operations to the lower inode occur through that
104 * file. When the first eCryptfs dentry that interposes with the first
105 * lower dentry for that inode is created, this function creates the
106 * lower file struct and associates it with the eCryptfs
107 * inode. When all eCryptfs files associated with the inode are released, the
108 * file is closed.
109 *
110 * The lower file will be opened with read/write permissions, if
111 * possible. Otherwise, it is opened read-only.
112 *
113 * This function does nothing if a lower file is already
114 * associated with the eCryptfs inode.
115 *
116 * Returns zero on success; non-zero otherwise
117 */
118static int ecryptfs_init_lower_file(struct dentry *dentry,
119				    struct file **lower_file)
120{
121	const struct cred *cred = current_cred();
122	struct path *path = ecryptfs_dentry_to_lower_path(dentry);
123	int rc;
124
125	rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
126				      cred);
127	if (rc) {
128		printk(KERN_ERR "Error opening lower file "
129		       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
130		       "rc = [%d]\n", path->dentry, path->mnt, rc);
131		(*lower_file) = NULL;
132	}
133	return rc;
134}
135
136int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
137{
138	struct ecryptfs_inode_info *inode_info;
139	int count, rc = 0;
140
141	inode_info = ecryptfs_inode_to_private(inode);
142	mutex_lock(&inode_info->lower_file_mutex);
143	count = atomic_inc_return(&inode_info->lower_file_count);
144	if (WARN_ON_ONCE(count < 1))
145		rc = -EINVAL;
146	else if (count == 1) {
147		rc = ecryptfs_init_lower_file(dentry,
148					      &inode_info->lower_file);
149		if (rc)
150			atomic_set(&inode_info->lower_file_count, 0);
151	}
152	mutex_unlock(&inode_info->lower_file_mutex);
153	return rc;
154}
155
156void ecryptfs_put_lower_file(struct inode *inode)
157{
158	struct ecryptfs_inode_info *inode_info;
159
160	inode_info = ecryptfs_inode_to_private(inode);
161	if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
162				      &inode_info->lower_file_mutex)) {
163		filemap_write_and_wait(inode->i_mapping);
164		fput(inode_info->lower_file);
165		inode_info->lower_file = NULL;
166		mutex_unlock(&inode_info->lower_file_mutex);
167	}
168}
169
170enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
171       ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
172       ecryptfs_opt_ecryptfs_key_bytes,
173       ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
174       ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
175       ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
176       ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
177       ecryptfs_opt_check_dev_ruid,
178       ecryptfs_opt_err };
179
180static const match_table_t tokens = {
181	{ecryptfs_opt_sig, "sig=%s"},
182	{ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
183	{ecryptfs_opt_cipher, "cipher=%s"},
184	{ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
185	{ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
186	{ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
187	{ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
188	{ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
189	{ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
190	{ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
191	{ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
192	{ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
193	{ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
194	{ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
195	{ecryptfs_opt_err, NULL}
196};
197
198static int ecryptfs_init_global_auth_toks(
199	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
200{
201	struct ecryptfs_global_auth_tok *global_auth_tok;
202	struct ecryptfs_auth_tok *auth_tok;
203	int rc = 0;
204
205	list_for_each_entry(global_auth_tok,
206			    &mount_crypt_stat->global_auth_tok_list,
207			    mount_crypt_stat_list) {
208		rc = ecryptfs_keyring_auth_tok_for_sig(
209			&global_auth_tok->global_auth_tok_key, &auth_tok,
210			global_auth_tok->sig);
211		if (rc) {
212			printk(KERN_ERR "Could not find valid key in user "
213			       "session keyring for sig specified in mount "
214			       "option: [%s]\n", global_auth_tok->sig);
215			global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
216			goto out;
217		} else {
218			global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
219			up_write(&(global_auth_tok->global_auth_tok_key)->sem);
220		}
221	}
222out:
223	return rc;
224}
225
226static void ecryptfs_init_mount_crypt_stat(
227	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
228{
229	memset((void *)mount_crypt_stat, 0,
230	       sizeof(struct ecryptfs_mount_crypt_stat));
231	INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
232	mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
233	mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
234}
235
236/**
237 * ecryptfs_parse_options
238 * @sb: The ecryptfs super block
239 * @options: The options passed to the kernel
240 * @check_ruid: set to 1 if device uid should be checked against the ruid
241 *
242 * Parse mount options:
243 * debug=N 	   - ecryptfs_verbosity level for debug output
244 * sig=XXX	   - description(signature) of the key to use
245 *
246 * Returns the dentry object of the lower-level (lower/interposed)
247 * directory; We want to mount our stackable file system on top of
248 * that lower directory.
249 *
250 * The signature of the key to use must be the description of a key
251 * already in the keyring. Mounting will fail if the key can not be
252 * found.
253 *
254 * Returns zero on success; non-zero on error
255 */
256static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
257				  uid_t *check_ruid)
258{
259	char *p;
260	int rc = 0;
261	int sig_set = 0;
262	int cipher_name_set = 0;
263	int fn_cipher_name_set = 0;
264	int cipher_key_bytes;
265	int cipher_key_bytes_set = 0;
266	int fn_cipher_key_bytes;
267	int fn_cipher_key_bytes_set = 0;
268	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
269		&sbi->mount_crypt_stat;
270	substring_t args[MAX_OPT_ARGS];
271	int token;
272	char *sig_src;
273	char *cipher_name_dst;
274	char *cipher_name_src;
275	char *fn_cipher_name_dst;
276	char *fn_cipher_name_src;
277	char *fnek_dst;
278	char *fnek_src;
279	char *cipher_key_bytes_src;
280	char *fn_cipher_key_bytes_src;
281	u8 cipher_code;
282
283	*check_ruid = 0;
284
285	if (!options) {
286		rc = -EINVAL;
287		goto out;
288	}
289	ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
290	while ((p = strsep(&options, ",")) != NULL) {
291		if (!*p)
292			continue;
293		token = match_token(p, tokens, args);
294		switch (token) {
295		case ecryptfs_opt_sig:
296		case ecryptfs_opt_ecryptfs_sig:
297			sig_src = args[0].from;
298			rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
299							  sig_src, 0);
300			if (rc) {
301				printk(KERN_ERR "Error attempting to register "
302				       "global sig; rc = [%d]\n", rc);
303				goto out;
304			}
305			sig_set = 1;
306			break;
307		case ecryptfs_opt_cipher:
308		case ecryptfs_opt_ecryptfs_cipher:
309			cipher_name_src = args[0].from;
310			cipher_name_dst =
311				mount_crypt_stat->
312				global_default_cipher_name;
313			strncpy(cipher_name_dst, cipher_name_src,
314				ECRYPTFS_MAX_CIPHER_NAME_SIZE);
315			cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
316			cipher_name_set = 1;
317			break;
318		case ecryptfs_opt_ecryptfs_key_bytes:
319			cipher_key_bytes_src = args[0].from;
320			cipher_key_bytes =
321				(int)simple_strtol(cipher_key_bytes_src,
322						   &cipher_key_bytes_src, 0);
323			mount_crypt_stat->global_default_cipher_key_size =
324				cipher_key_bytes;
325			cipher_key_bytes_set = 1;
326			break;
327		case ecryptfs_opt_passthrough:
328			mount_crypt_stat->flags |=
329				ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
330			break;
331		case ecryptfs_opt_xattr_metadata:
332			mount_crypt_stat->flags |=
333				ECRYPTFS_XATTR_METADATA_ENABLED;
334			break;
335		case ecryptfs_opt_encrypted_view:
336			mount_crypt_stat->flags |=
337				ECRYPTFS_XATTR_METADATA_ENABLED;
338			mount_crypt_stat->flags |=
339				ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
340			break;
341		case ecryptfs_opt_fnek_sig:
342			fnek_src = args[0].from;
343			fnek_dst =
344				mount_crypt_stat->global_default_fnek_sig;
345			strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
346			mount_crypt_stat->global_default_fnek_sig[
347				ECRYPTFS_SIG_SIZE_HEX] = '\0';
348			rc = ecryptfs_add_global_auth_tok(
349				mount_crypt_stat,
350				mount_crypt_stat->global_default_fnek_sig,
351				ECRYPTFS_AUTH_TOK_FNEK);
352			if (rc) {
353				printk(KERN_ERR "Error attempting to register "
354				       "global fnek sig [%s]; rc = [%d]\n",
355				       mount_crypt_stat->global_default_fnek_sig,
356				       rc);
357				goto out;
358			}
359			mount_crypt_stat->flags |=
360				(ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
361				 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
362			break;
363		case ecryptfs_opt_fn_cipher:
364			fn_cipher_name_src = args[0].from;
365			fn_cipher_name_dst =
366				mount_crypt_stat->global_default_fn_cipher_name;
367			strncpy(fn_cipher_name_dst, fn_cipher_name_src,
368				ECRYPTFS_MAX_CIPHER_NAME_SIZE);
369			mount_crypt_stat->global_default_fn_cipher_name[
370				ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
371			fn_cipher_name_set = 1;
372			break;
373		case ecryptfs_opt_fn_cipher_key_bytes:
374			fn_cipher_key_bytes_src = args[0].from;
375			fn_cipher_key_bytes =
376				(int)simple_strtol(fn_cipher_key_bytes_src,
377						   &fn_cipher_key_bytes_src, 0);
378			mount_crypt_stat->global_default_fn_cipher_key_bytes =
379				fn_cipher_key_bytes;
380			fn_cipher_key_bytes_set = 1;
381			break;
382		case ecryptfs_opt_unlink_sigs:
383			mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
384			break;
385		case ecryptfs_opt_mount_auth_tok_only:
386			mount_crypt_stat->flags |=
387				ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
388			break;
389		case ecryptfs_opt_check_dev_ruid:
390			*check_ruid = 1;
391			break;
392		case ecryptfs_opt_err:
393		default:
394			printk(KERN_WARNING
395			       "%s: eCryptfs: unrecognized option [%s]\n",
396			       __func__, p);
397		}
398	}
399	if (!sig_set) {
400		rc = -EINVAL;
401		ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
402				"auth tok signature as a mount "
403				"parameter; see the eCryptfs README\n");
404		goto out;
405	}
406	if (!cipher_name_set) {
407		int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
408
409		BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
410		strcpy(mount_crypt_stat->global_default_cipher_name,
411		       ECRYPTFS_DEFAULT_CIPHER);
412	}
413	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
414	    && !fn_cipher_name_set)
415		strcpy(mount_crypt_stat->global_default_fn_cipher_name,
416		       mount_crypt_stat->global_default_cipher_name);
417	if (!cipher_key_bytes_set)
418		mount_crypt_stat->global_default_cipher_key_size = 0;
419	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
420	    && !fn_cipher_key_bytes_set)
421		mount_crypt_stat->global_default_fn_cipher_key_bytes =
422			mount_crypt_stat->global_default_cipher_key_size;
423
424	cipher_code = ecryptfs_code_for_cipher_string(
425		mount_crypt_stat->global_default_cipher_name,
426		mount_crypt_stat->global_default_cipher_key_size);
427	if (!cipher_code) {
428		ecryptfs_printk(KERN_ERR,
429				"eCryptfs doesn't support cipher: %s",
430				mount_crypt_stat->global_default_cipher_name);
431		rc = -EINVAL;
432		goto out;
433	}
434
435	mutex_lock(&key_tfm_list_mutex);
436	if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
437				 NULL)) {
438		rc = ecryptfs_add_new_key_tfm(
439			NULL, mount_crypt_stat->global_default_cipher_name,
440			mount_crypt_stat->global_default_cipher_key_size);
441		if (rc) {
442			printk(KERN_ERR "Error attempting to initialize "
443			       "cipher with name = [%s] and key size = [%td]; "
444			       "rc = [%d]\n",
445			       mount_crypt_stat->global_default_cipher_name,
446			       mount_crypt_stat->global_default_cipher_key_size,
447			       rc);
448			rc = -EINVAL;
449			mutex_unlock(&key_tfm_list_mutex);
450			goto out;
451		}
452	}
453	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
454	    && !ecryptfs_tfm_exists(
455		    mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
456		rc = ecryptfs_add_new_key_tfm(
457			NULL, mount_crypt_stat->global_default_fn_cipher_name,
458			mount_crypt_stat->global_default_fn_cipher_key_bytes);
459		if (rc) {
460			printk(KERN_ERR "Error attempting to initialize "
461			       "cipher with name = [%s] and key size = [%td]; "
462			       "rc = [%d]\n",
463			       mount_crypt_stat->global_default_fn_cipher_name,
464			       mount_crypt_stat->global_default_fn_cipher_key_bytes,
465			       rc);
466			rc = -EINVAL;
467			mutex_unlock(&key_tfm_list_mutex);
468			goto out;
469		}
470	}
471	mutex_unlock(&key_tfm_list_mutex);
472	rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
473	if (rc)
474		printk(KERN_WARNING "One or more global auth toks could not "
475		       "properly register; rc = [%d]\n", rc);
476out:
477	return rc;
478}
479
480struct kmem_cache *ecryptfs_sb_info_cache;
481static struct file_system_type ecryptfs_fs_type;
482
483/**
484 * ecryptfs_get_sb
485 * @fs_type
486 * @flags
487 * @dev_name: The path to mount over
488 * @raw_data: The options passed into the kernel
489 */
490static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
491			const char *dev_name, void *raw_data)
492{
493	struct super_block *s;
494	struct ecryptfs_sb_info *sbi;
495	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
496	struct ecryptfs_dentry_info *root_info;
497	const char *err = "Getting sb failed";
498	struct inode *inode;
499	struct path path;
500	uid_t check_ruid;
501	int rc;
502
503	sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
504	if (!sbi) {
505		rc = -ENOMEM;
506		goto out;
507	}
508
509	rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
510	if (rc) {
511		err = "Error parsing options";
512		goto out;
513	}
514	mount_crypt_stat = &sbi->mount_crypt_stat;
515
516	s = sget(fs_type, NULL, set_anon_super, flags, NULL);
517	if (IS_ERR(s)) {
518		rc = PTR_ERR(s);
519		goto out;
520	}
521
522	rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs");
523	if (rc)
524		goto out1;
525
526	ecryptfs_set_superblock_private(s, sbi);
527	s->s_bdi = &sbi->bdi;
528
529	/* ->kill_sb() will take care of sbi after that point */
530	sbi = NULL;
531	s->s_op = &ecryptfs_sops;
 
532	s->s_d_op = &ecryptfs_dops;
533
534	err = "Reading sb failed";
535	rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
536	if (rc) {
537		ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
538		goto out1;
539	}
540	if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
541		rc = -EINVAL;
542		printk(KERN_ERR "Mount on filesystem of type "
543			"eCryptfs explicitly disallowed due to "
544			"known incompatibilities\n");
545		goto out_free;
546	}
547
548	if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
549		rc = -EPERM;
550		printk(KERN_ERR "Mount of device (uid: %d) not owned by "
551		       "requested user (uid: %d)\n",
552			i_uid_read(d_inode(path.dentry)),
553			from_kuid(&init_user_ns, current_uid()));
554		goto out_free;
555	}
556
557	ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
558
559	/**
560	 * Set the POSIX ACL flag based on whether they're enabled in the lower
561	 * mount.
562	 */
563	s->s_flags = flags & ~MS_POSIXACL;
564	s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL;
565
566	/**
567	 * Force a read-only eCryptfs mount when:
568	 *   1) The lower mount is ro
569	 *   2) The ecryptfs_encrypted_view mount option is specified
570	 */
571	if (path.dentry->d_sb->s_flags & MS_RDONLY ||
572	    mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
573		s->s_flags |= MS_RDONLY;
574
575	s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
576	s->s_blocksize = path.dentry->d_sb->s_blocksize;
577	s->s_magic = ECRYPTFS_SUPER_MAGIC;
578	s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
579
580	rc = -EINVAL;
581	if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
582		pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
583		goto out_free;
584	}
585
586	inode = ecryptfs_get_inode(d_inode(path.dentry), s);
587	rc = PTR_ERR(inode);
588	if (IS_ERR(inode))
589		goto out_free;
590
591	s->s_root = d_make_root(inode);
592	if (!s->s_root) {
593		rc = -ENOMEM;
594		goto out_free;
595	}
596
597	rc = -ENOMEM;
598	root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
599	if (!root_info)
600		goto out_free;
601
602	/* ->kill_sb() will take care of root_info */
603	ecryptfs_set_dentry_private(s->s_root, root_info);
604	root_info->lower_path = path;
605
606	s->s_flags |= MS_ACTIVE;
607	return dget(s->s_root);
608
609out_free:
610	path_put(&path);
611out1:
612	deactivate_locked_super(s);
613out:
614	if (sbi) {
615		ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
616		kmem_cache_free(ecryptfs_sb_info_cache, sbi);
617	}
618	printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
619	return ERR_PTR(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 */
628static void ecryptfs_kill_block_super(struct super_block *sb)
629{
630	struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
631	kill_anon_super(sb);
632	if (!sb_info)
633		return;
634	ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
635	bdi_destroy(&sb_info->bdi);
636	kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
637}
638
639static struct file_system_type ecryptfs_fs_type = {
640	.owner = THIS_MODULE,
641	.name = "ecryptfs",
642	.mount = ecryptfs_mount,
643	.kill_sb = ecryptfs_kill_block_super,
644	.fs_flags = 0
645};
646MODULE_ALIAS_FS("ecryptfs");
647
648/**
649 * inode_info_init_once
650 *
651 * Initializes the ecryptfs_inode_info_cache when it is created
652 */
653static void
654inode_info_init_once(void *vptr)
655{
656	struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
657
658	inode_init_once(&ei->vfs_inode);
659}
660
661static struct ecryptfs_cache_info {
662	struct kmem_cache **cache;
663	const char *name;
664	size_t size;
665	unsigned long flags;
666	void (*ctor)(void *obj);
667} ecryptfs_cache_infos[] = {
668	{
669		.cache = &ecryptfs_auth_tok_list_item_cache,
670		.name = "ecryptfs_auth_tok_list_item",
671		.size = sizeof(struct ecryptfs_auth_tok_list_item),
672	},
673	{
674		.cache = &ecryptfs_file_info_cache,
675		.name = "ecryptfs_file_cache",
676		.size = sizeof(struct ecryptfs_file_info),
677	},
678	{
679		.cache = &ecryptfs_dentry_info_cache,
680		.name = "ecryptfs_dentry_info_cache",
681		.size = sizeof(struct ecryptfs_dentry_info),
682	},
683	{
684		.cache = &ecryptfs_inode_info_cache,
685		.name = "ecryptfs_inode_cache",
686		.size = sizeof(struct ecryptfs_inode_info),
687		.flags = SLAB_ACCOUNT,
688		.ctor = inode_info_init_once,
689	},
690	{
691		.cache = &ecryptfs_sb_info_cache,
692		.name = "ecryptfs_sb_cache",
693		.size = sizeof(struct ecryptfs_sb_info),
694	},
695	{
696		.cache = &ecryptfs_header_cache,
697		.name = "ecryptfs_headers",
698		.size = PAGE_SIZE,
699	},
700	{
701		.cache = &ecryptfs_xattr_cache,
702		.name = "ecryptfs_xattr_cache",
703		.size = PAGE_SIZE,
704	},
705	{
706		.cache = &ecryptfs_key_record_cache,
707		.name = "ecryptfs_key_record_cache",
708		.size = sizeof(struct ecryptfs_key_record),
709	},
710	{
711		.cache = &ecryptfs_key_sig_cache,
712		.name = "ecryptfs_key_sig_cache",
713		.size = sizeof(struct ecryptfs_key_sig),
714	},
715	{
716		.cache = &ecryptfs_global_auth_tok_cache,
717		.name = "ecryptfs_global_auth_tok_cache",
718		.size = sizeof(struct ecryptfs_global_auth_tok),
719	},
720	{
721		.cache = &ecryptfs_key_tfm_cache,
722		.name = "ecryptfs_key_tfm_cache",
723		.size = sizeof(struct ecryptfs_key_tfm),
724	},
725};
726
727static void ecryptfs_free_kmem_caches(void)
728{
729	int i;
730
731	/*
732	 * Make sure all delayed rcu free inodes are flushed before we
733	 * destroy cache.
734	 */
735	rcu_barrier();
736
737	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
738		struct ecryptfs_cache_info *info;
739
740		info = &ecryptfs_cache_infos[i];
741		if (*(info->cache))
742			kmem_cache_destroy(*(info->cache));
743	}
744}
745
746/**
747 * ecryptfs_init_kmem_caches
748 *
749 * Returns zero on success; non-zero otherwise
750 */
751static int ecryptfs_init_kmem_caches(void)
752{
753	int i;
754
755	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
756		struct ecryptfs_cache_info *info;
757
758		info = &ecryptfs_cache_infos[i];
759		*(info->cache) = kmem_cache_create(info->name, info->size, 0,
760				SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
761		if (!*(info->cache)) {
762			ecryptfs_free_kmem_caches();
763			ecryptfs_printk(KERN_WARNING, "%s: "
764					"kmem_cache_create failed\n",
765					info->name);
766			return -ENOMEM;
767		}
768	}
769	return 0;
770}
771
772static struct kobject *ecryptfs_kobj;
773
774static ssize_t version_show(struct kobject *kobj,
775			    struct kobj_attribute *attr, char *buff)
776{
777	return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
778}
779
780static struct kobj_attribute version_attr = __ATTR_RO(version);
781
782static struct attribute *attributes[] = {
783	&version_attr.attr,
784	NULL,
785};
786
787static struct attribute_group attr_group = {
788	.attrs = attributes,
789};
790
791static int do_sysfs_registration(void)
792{
793	int rc;
794
795	ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
796	if (!ecryptfs_kobj) {
797		printk(KERN_ERR "Unable to create ecryptfs kset\n");
798		rc = -ENOMEM;
799		goto out;
800	}
801	rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
802	if (rc) {
803		printk(KERN_ERR
804		       "Unable to create ecryptfs version attributes\n");
805		kobject_put(ecryptfs_kobj);
806	}
807out:
808	return rc;
809}
810
811static void do_sysfs_unregistration(void)
812{
813	sysfs_remove_group(ecryptfs_kobj, &attr_group);
814	kobject_put(ecryptfs_kobj);
815}
816
817static int __init ecryptfs_init(void)
818{
819	int rc;
820
821	if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
822		rc = -EINVAL;
823		ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
824				"larger than the host's page size, and so "
825				"eCryptfs cannot run on this system. The "
826				"default eCryptfs extent size is [%u] bytes; "
827				"the page size is [%lu] bytes.\n",
828				ECRYPTFS_DEFAULT_EXTENT_SIZE,
829				(unsigned long)PAGE_SIZE);
830		goto out;
831	}
832	rc = ecryptfs_init_kmem_caches();
833	if (rc) {
834		printk(KERN_ERR
835		       "Failed to allocate one or more kmem_cache objects\n");
836		goto out;
837	}
838	rc = do_sysfs_registration();
839	if (rc) {
840		printk(KERN_ERR "sysfs registration failed\n");
841		goto out_free_kmem_caches;
842	}
843	rc = ecryptfs_init_kthread();
844	if (rc) {
845		printk(KERN_ERR "%s: kthread initialization failed; "
846		       "rc = [%d]\n", __func__, rc);
847		goto out_do_sysfs_unregistration;
848	}
849	rc = ecryptfs_init_messaging();
850	if (rc) {
851		printk(KERN_ERR "Failure occurred while attempting to "
852				"initialize the communications channel to "
853				"ecryptfsd\n");
854		goto out_destroy_kthread;
855	}
856	rc = ecryptfs_init_crypto();
857	if (rc) {
858		printk(KERN_ERR "Failure whilst attempting to init crypto; "
859		       "rc = [%d]\n", rc);
860		goto out_release_messaging;
861	}
862	rc = register_filesystem(&ecryptfs_fs_type);
863	if (rc) {
864		printk(KERN_ERR "Failed to register filesystem\n");
865		goto out_destroy_crypto;
866	}
867	if (ecryptfs_verbosity > 0)
868		printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
869			"will be written to the syslog!\n", ecryptfs_verbosity);
870
871	goto out;
872out_destroy_crypto:
873	ecryptfs_destroy_crypto();
874out_release_messaging:
875	ecryptfs_release_messaging();
876out_destroy_kthread:
877	ecryptfs_destroy_kthread();
878out_do_sysfs_unregistration:
879	do_sysfs_unregistration();
880out_free_kmem_caches:
881	ecryptfs_free_kmem_caches();
882out:
883	return rc;
884}
885
886static void __exit ecryptfs_exit(void)
887{
888	int rc;
889
890	rc = ecryptfs_destroy_crypto();
891	if (rc)
892		printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
893		       "rc = [%d]\n", rc);
894	ecryptfs_release_messaging();
895	ecryptfs_destroy_kthread();
896	do_sysfs_unregistration();
897	unregister_filesystem(&ecryptfs_fs_type);
898	ecryptfs_free_kmem_caches();
899}
900
901MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
902MODULE_DESCRIPTION("eCryptfs");
903
904MODULE_LICENSE("GPL");
905
906module_init(ecryptfs_init)
907module_exit(ecryptfs_exit)