Merge branch 'for-np' of git://git.wormnet.eu/alex/ts78xx into orion/master
[linux-2.6] / fs / ecryptfs / main.c
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 || IS_ERR(inode_info->lower_file)) {
133                         printk(KERN_ERR "Error opening lower persistent file "
134                                "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
135                                "rc = [%d]\n", lower_dentry, lower_mnt, rc);
136                         rc = PTR_ERR(inode_info->lower_file);
137                         inode_info->lower_file = NULL;
138                 }
139         }
140         mutex_unlock(&inode_info->lower_file_mutex);
141         return rc;
142 }
143
144 /**
145  * ecryptfs_interpose
146  * @lower_dentry: Existing dentry in the lower filesystem
147  * @dentry: ecryptfs' dentry
148  * @sb: ecryptfs's super_block
149  * @flags: flags to govern behavior of interpose procedure
150  *
151  * Interposes upper and lower dentries.
152  *
153  * Returns zero on success; non-zero otherwise
154  */
155 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
156                        struct super_block *sb, u32 flags)
157 {
158         struct inode *lower_inode;
159         struct inode *inode;
160         int rc = 0;
161
162         lower_inode = lower_dentry->d_inode;
163         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
164                 rc = -EXDEV;
165                 goto out;
166         }
167         if (!igrab(lower_inode)) {
168                 rc = -ESTALE;
169                 goto out;
170         }
171         inode = iget5_locked(sb, (unsigned long)lower_inode,
172                              ecryptfs_inode_test, ecryptfs_inode_set,
173                              lower_inode);
174         if (!inode) {
175                 rc = -EACCES;
176                 iput(lower_inode);
177                 goto out;
178         }
179         if (inode->i_state & I_NEW)
180                 unlock_new_inode(inode);
181         else
182                 iput(lower_inode);
183         if (S_ISLNK(lower_inode->i_mode))
184                 inode->i_op = &ecryptfs_symlink_iops;
185         else if (S_ISDIR(lower_inode->i_mode))
186                 inode->i_op = &ecryptfs_dir_iops;
187         if (S_ISDIR(lower_inode->i_mode))
188                 inode->i_fop = &ecryptfs_dir_fops;
189         if (special_file(lower_inode->i_mode))
190                 init_special_inode(inode, lower_inode->i_mode,
191                                    lower_inode->i_rdev);
192         dentry->d_op = &ecryptfs_dops;
193         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
194                 d_add(dentry, inode);
195         else
196                 d_instantiate(dentry, inode);
197         fsstack_copy_attr_all(inode, lower_inode, NULL);
198         /* This size will be overwritten for real files w/ headers and
199          * other metadata */
200         fsstack_copy_inode_size(inode, lower_inode);
201 out:
202         return rc;
203 }
204
205 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
206        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
207        ecryptfs_opt_ecryptfs_key_bytes,
208        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
209        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
210        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
211        ecryptfs_opt_err };
212
213 static const match_table_t tokens = {
214         {ecryptfs_opt_sig, "sig=%s"},
215         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
216         {ecryptfs_opt_cipher, "cipher=%s"},
217         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
218         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
219         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
220         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
221         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
222         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
223         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
224         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
225         {ecryptfs_opt_err, NULL}
226 };
227
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);
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                         if (rc) {
375                                 printk(KERN_ERR "Error attempting to register "
376                                        "global fnek sig [%s]; rc = [%d]\n",
377                                        mount_crypt_stat->global_default_fnek_sig,
378                                        rc);
379                                 goto out;
380                         }
381                         mount_crypt_stat->flags |=
382                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
383                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
384                         break;
385                 case ecryptfs_opt_fn_cipher:
386                         fn_cipher_name_src = args[0].from;
387                         fn_cipher_name_dst =
388                                 mount_crypt_stat->global_default_fn_cipher_name;
389                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
390                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
391                         mount_crypt_stat->global_default_fn_cipher_name[
392                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
393                         fn_cipher_name_set = 1;
394                         break;
395                 case ecryptfs_opt_fn_cipher_key_bytes:
396                         fn_cipher_key_bytes_src = args[0].from;
397                         fn_cipher_key_bytes =
398                                 (int)simple_strtol(fn_cipher_key_bytes_src,
399                                                    &fn_cipher_key_bytes_src, 0);
400                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
401                                 fn_cipher_key_bytes;
402                         fn_cipher_key_bytes_set = 1;
403                         break;
404                 case ecryptfs_opt_err:
405                 default:
406                         printk(KERN_WARNING
407                                "%s: eCryptfs: unrecognized option [%s]\n",
408                                __func__, p);
409                 }
410         }
411         if (!sig_set) {
412                 rc = -EINVAL;
413                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
414                                 "auth tok signature as a mount "
415                                 "parameter; see the eCryptfs README\n");
416                 goto out;
417         }
418         if (!cipher_name_set) {
419                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
420
421                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
422                 strcpy(mount_crypt_stat->global_default_cipher_name,
423                        ECRYPTFS_DEFAULT_CIPHER);
424         }
425         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
426             && !fn_cipher_name_set)
427                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
428                        mount_crypt_stat->global_default_cipher_name);
429         if (!cipher_key_bytes_set)
430                 mount_crypt_stat->global_default_cipher_key_size = 0;
431         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
432             && !fn_cipher_key_bytes_set)
433                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
434                         mount_crypt_stat->global_default_cipher_key_size;
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);
476 out:
477         return rc;
478 }
479
480 struct kmem_cache *ecryptfs_sb_info_cache;
481
482 /**
483  * ecryptfs_fill_super
484  * @sb: The ecryptfs super block
485  * @raw_data: The options passed to mount
486  * @silent: Not used but required by function prototype
487  *
488  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
489  *
490  * Returns zero on success; non-zero otherwise
491  */
492 static int
493 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
494 {
495         int rc = 0;
496
497         /* Released in ecryptfs_put_super() */
498         ecryptfs_set_superblock_private(sb,
499                                         kmem_cache_zalloc(ecryptfs_sb_info_cache,
500                                                          GFP_KERNEL));
501         if (!ecryptfs_superblock_to_private(sb)) {
502                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
503                 rc = -ENOMEM;
504                 goto out;
505         }
506         sb->s_op = &ecryptfs_sops;
507         /* Released through deactivate_super(sb) from get_sb_nodev */
508         sb->s_root = d_alloc(NULL, &(const struct qstr) {
509                              .hash = 0,.name = "/",.len = 1});
510         if (!sb->s_root) {
511                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
512                 rc = -ENOMEM;
513                 goto out;
514         }
515         sb->s_root->d_op = &ecryptfs_dops;
516         sb->s_root->d_sb = sb;
517         sb->s_root->d_parent = sb->s_root;
518         /* Released in d_release when dput(sb->s_root) is called */
519         /* through deactivate_super(sb) from get_sb_nodev() */
520         ecryptfs_set_dentry_private(sb->s_root,
521                                     kmem_cache_zalloc(ecryptfs_dentry_info_cache,
522                                                      GFP_KERNEL));
523         if (!ecryptfs_dentry_to_private(sb->s_root)) {
524                 ecryptfs_printk(KERN_ERR,
525                                 "dentry_info_cache alloc failed\n");
526                 rc = -ENOMEM;
527                 goto out;
528         }
529         rc = 0;
530 out:
531         /* Should be able to rely on deactivate_super called from
532          * get_sb_nodev */
533         return rc;
534 }
535
536 /**
537  * ecryptfs_read_super
538  * @sb: The ecryptfs super block
539  * @dev_name: The path to mount over
540  *
541  * Read the super block of the lower filesystem, and use
542  * ecryptfs_interpose to create our initial inode and super block
543  * struct.
544  */
545 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
546 {
547         struct path path;
548         int rc;
549
550         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
551         if (rc) {
552                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
553                 goto out;
554         }
555         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
556         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
557         sb->s_blocksize = path.dentry->d_sb->s_blocksize;
558         ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
559         ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
560         rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
561         if (rc)
562                 goto out_free;
563         rc = 0;
564         goto out;
565 out_free:
566         path_put(&path);
567 out:
568         return rc;
569 }
570
571 /**
572  * ecryptfs_get_sb
573  * @fs_type
574  * @flags
575  * @dev_name: The path to mount over
576  * @raw_data: The options passed into the kernel
577  *
578  * The whole ecryptfs_get_sb process is broken into 4 functions:
579  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
580  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
581  *                        with as much information as it can before needing
582  *                        the lower filesystem.
583  * ecryptfs_read_super(): this accesses the lower filesystem and uses
584  *                        ecryptfs_interpolate to perform most of the linking
585  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
586  */
587 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
588                         const char *dev_name, void *raw_data,
589                         struct vfsmount *mnt)
590 {
591         int rc;
592         struct super_block *sb;
593
594         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
595         if (rc < 0) {
596                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
597                 goto out;
598         }
599         sb = mnt->mnt_sb;
600         rc = ecryptfs_parse_options(sb, raw_data);
601         if (rc) {
602                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
603                 goto out_abort;
604         }
605         rc = ecryptfs_read_super(sb, dev_name);
606         if (rc) {
607                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
608                 goto out_abort;
609         }
610         goto out;
611 out_abort:
612         dput(sb->s_root);
613         up_write(&sb->s_umount);
614         deactivate_super(sb);
615 out:
616         return rc;
617 }
618
619 /**
620  * ecryptfs_kill_block_super
621  * @sb: The ecryptfs super block
622  *
623  * Used to bring the superblock down and free the private data.
624  * Private data is free'd in ecryptfs_put_super()
625  */
626 static void ecryptfs_kill_block_super(struct super_block *sb)
627 {
628         generic_shutdown_super(sb);
629 }
630
631 static struct file_system_type ecryptfs_fs_type = {
632         .owner = THIS_MODULE,
633         .name = "ecryptfs",
634         .get_sb = ecryptfs_get_sb,
635         .kill_sb = ecryptfs_kill_block_super,
636         .fs_flags = 0
637 };
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_1,
686                 .name = "ecryptfs_headers_1",
687                 .size = PAGE_CACHE_SIZE,
688         },
689         {
690                 .cache = &ecryptfs_header_cache_2,
691                 .name = "ecryptfs_headers_2",
692                 .size = PAGE_CACHE_SIZE,
693         },
694         {
695                 .cache = &ecryptfs_xattr_cache,
696                 .name = "ecryptfs_xattr_cache",
697                 .size = PAGE_CACHE_SIZE,
698         },
699         {
700                 .cache = &ecryptfs_key_record_cache,
701                 .name = "ecryptfs_key_record_cache",
702                 .size = sizeof(struct ecryptfs_key_record),
703         },
704         {
705                 .cache = &ecryptfs_key_sig_cache,
706                 .name = "ecryptfs_key_sig_cache",
707                 .size = sizeof(struct ecryptfs_key_sig),
708         },
709         {
710                 .cache = &ecryptfs_global_auth_tok_cache,
711                 .name = "ecryptfs_global_auth_tok_cache",
712                 .size = sizeof(struct ecryptfs_global_auth_tok),
713         },
714         {
715                 .cache = &ecryptfs_key_tfm_cache,
716                 .name = "ecryptfs_key_tfm_cache",
717                 .size = sizeof(struct ecryptfs_key_tfm),
718         },
719         {
720                 .cache = &ecryptfs_open_req_cache,
721                 .name = "ecryptfs_open_req_cache",
722                 .size = sizeof(struct ecryptfs_open_req),
723         },
724 };
725
726 static void ecryptfs_free_kmem_caches(void)
727 {
728         int i;
729
730         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
731                 struct ecryptfs_cache_info *info;
732
733                 info = &ecryptfs_cache_infos[i];
734                 if (*(info->cache))
735                         kmem_cache_destroy(*(info->cache));
736         }
737 }
738
739 /**
740  * ecryptfs_init_kmem_caches
741  *
742  * Returns zero on success; non-zero otherwise
743  */
744 static int ecryptfs_init_kmem_caches(void)
745 {
746         int i;
747
748         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
749                 struct ecryptfs_cache_info *info;
750
751                 info = &ecryptfs_cache_infos[i];
752                 *(info->cache) = kmem_cache_create(info->name, info->size,
753                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
754                 if (!*(info->cache)) {
755                         ecryptfs_free_kmem_caches();
756                         ecryptfs_printk(KERN_WARNING, "%s: "
757                                         "kmem_cache_create failed\n",
758                                         info->name);
759                         return -ENOMEM;
760                 }
761         }
762         return 0;
763 }
764
765 static struct kobject *ecryptfs_kobj;
766
767 static ssize_t version_show(struct kobject *kobj,
768                             struct kobj_attribute *attr, char *buff)
769 {
770         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
771 }
772
773 static struct kobj_attribute version_attr = __ATTR_RO(version);
774
775 static struct attribute *attributes[] = {
776         &version_attr.attr,
777         NULL,
778 };
779
780 static struct attribute_group attr_group = {
781         .attrs = attributes,
782 };
783
784 static int do_sysfs_registration(void)
785 {
786         int rc;
787
788         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
789         if (!ecryptfs_kobj) {
790                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
791                 rc = -ENOMEM;
792                 goto out;
793         }
794         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
795         if (rc) {
796                 printk(KERN_ERR
797                        "Unable to create ecryptfs version attributes\n");
798                 kobject_put(ecryptfs_kobj);
799         }
800 out:
801         return rc;
802 }
803
804 static void do_sysfs_unregistration(void)
805 {
806         sysfs_remove_group(ecryptfs_kobj, &attr_group);
807         kobject_put(ecryptfs_kobj);
808 }
809
810 static int __init ecryptfs_init(void)
811 {
812         int rc;
813
814         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
815                 rc = -EINVAL;
816                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
817                                 "larger than the host's page size, and so "
818                                 "eCryptfs cannot run on this system. The "
819                                 "default eCryptfs extent size is [%d] bytes; "
820                                 "the page size is [%d] bytes.\n",
821                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
822                 goto out;
823         }
824         rc = ecryptfs_init_kmem_caches();
825         if (rc) {
826                 printk(KERN_ERR
827                        "Failed to allocate one or more kmem_cache objects\n");
828                 goto out;
829         }
830         rc = register_filesystem(&ecryptfs_fs_type);
831         if (rc) {
832                 printk(KERN_ERR "Failed to register filesystem\n");
833                 goto out_free_kmem_caches;
834         }
835         rc = do_sysfs_registration();
836         if (rc) {
837                 printk(KERN_ERR "sysfs registration failed\n");
838                 goto out_unregister_filesystem;
839         }
840         rc = ecryptfs_init_kthread();
841         if (rc) {
842                 printk(KERN_ERR "%s: kthread initialization failed; "
843                        "rc = [%d]\n", __func__, rc);
844                 goto out_do_sysfs_unregistration;
845         }
846         rc = ecryptfs_init_messaging();
847         if (rc) {
848                 printk(KERN_ERR "Failure occured while attempting to "
849                                 "initialize the communications channel to "
850                                 "ecryptfsd\n");
851                 goto out_destroy_kthread;
852         }
853         rc = ecryptfs_init_crypto();
854         if (rc) {
855                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
856                        "rc = [%d]\n", rc);
857                 goto out_release_messaging;
858         }
859         if (ecryptfs_verbosity > 0)
860                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
861                         "will be written to the syslog!\n", ecryptfs_verbosity);
862
863         goto out;
864 out_release_messaging:
865         ecryptfs_release_messaging();
866 out_destroy_kthread:
867         ecryptfs_destroy_kthread();
868 out_do_sysfs_unregistration:
869         do_sysfs_unregistration();
870 out_unregister_filesystem:
871         unregister_filesystem(&ecryptfs_fs_type);
872 out_free_kmem_caches:
873         ecryptfs_free_kmem_caches();
874 out:
875         return rc;
876 }
877
878 static void __exit ecryptfs_exit(void)
879 {
880         int rc;
881
882         rc = ecryptfs_destroy_crypto();
883         if (rc)
884                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
885                        "rc = [%d]\n", rc);
886         ecryptfs_release_messaging();
887         ecryptfs_destroy_kthread();
888         do_sysfs_unregistration();
889         unregister_filesystem(&ecryptfs_fs_type);
890         ecryptfs_free_kmem_caches();
891 }
892
893 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
894 MODULE_DESCRIPTION("eCryptfs");
895
896 MODULE_LICENSE("GPL");
897
898 module_init(ecryptfs_init)
899 module_exit(ecryptfs_exit)