Untangling ima mess, part 2: deal with counters
[linux-2.6.git] / 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) {
133                         printk(KERN_ERR "Error opening lower persistent file "
134                                "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
135                                "rc = [%d]\n", lower_dentry, lower_mnt, rc);
136                         inode_info->lower_file = NULL;
137                 }
138         }
139         mutex_unlock(&inode_info->lower_file_mutex);
140         return rc;
141 }
142
143 /**
144  * ecryptfs_interpose
145  * @lower_dentry: Existing dentry in the lower filesystem
146  * @dentry: ecryptfs' dentry
147  * @sb: ecryptfs's super_block
148  * @flags: flags to govern behavior of interpose procedure
149  *
150  * Interposes upper and lower dentries.
151  *
152  * Returns zero on success; non-zero otherwise
153  */
154 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
155                        struct super_block *sb, u32 flags)
156 {
157         struct inode *lower_inode;
158         struct inode *inode;
159         int rc = 0;
160
161         lower_inode = lower_dentry->d_inode;
162         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
163                 rc = -EXDEV;
164                 goto out;
165         }
166         if (!igrab(lower_inode)) {
167                 rc = -ESTALE;
168                 goto out;
169         }
170         inode = iget5_locked(sb, (unsigned long)lower_inode,
171                              ecryptfs_inode_test, ecryptfs_inode_set,
172                              lower_inode);
173         if (!inode) {
174                 rc = -EACCES;
175                 iput(lower_inode);
176                 goto out;
177         }
178         if (inode->i_state & I_NEW)
179                 unlock_new_inode(inode);
180         else
181                 iput(lower_inode);
182         if (S_ISLNK(lower_inode->i_mode))
183                 inode->i_op = &ecryptfs_symlink_iops;
184         else if (S_ISDIR(lower_inode->i_mode))
185                 inode->i_op = &ecryptfs_dir_iops;
186         if (S_ISDIR(lower_inode->i_mode))
187                 inode->i_fop = &ecryptfs_dir_fops;
188         if (special_file(lower_inode->i_mode))
189                 init_special_inode(inode, lower_inode->i_mode,
190                                    lower_inode->i_rdev);
191         dentry->d_op = &ecryptfs_dops;
192         fsstack_copy_attr_all(inode, lower_inode, NULL);
193         /* This size will be overwritten for real files w/ headers and
194          * other metadata */
195         fsstack_copy_inode_size(inode, lower_inode);
196         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
197                 d_add(dentry, inode);
198         else
199                 d_instantiate(dentry, inode);
200 out:
201         return rc;
202 }
203
204 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
205        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
206        ecryptfs_opt_ecryptfs_key_bytes,
207        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
208        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
209        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
210        ecryptfs_opt_unlink_sigs, ecryptfs_opt_err };
211
212 static const match_table_t tokens = {
213         {ecryptfs_opt_sig, "sig=%s"},
214         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
215         {ecryptfs_opt_cipher, "cipher=%s"},
216         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
217         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
218         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
219         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
220         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
221         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
222         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
223         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
224         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
225         {ecryptfs_opt_err, NULL}
226 };
227
228 static int ecryptfs_init_global_auth_toks(
229         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
230 {
231         struct ecryptfs_global_auth_tok *global_auth_tok;
232         int rc = 0;
233
234         list_for_each_entry(global_auth_tok,
235                             &mount_crypt_stat->global_auth_tok_list,
236                             mount_crypt_stat_list) {
237                 rc = ecryptfs_keyring_auth_tok_for_sig(
238                         &global_auth_tok->global_auth_tok_key,
239                         &global_auth_tok->global_auth_tok,
240                         global_auth_tok->sig);
241                 if (rc) {
242                         printk(KERN_ERR "Could not find valid key in user "
243                                "session keyring for sig specified in mount "
244                                "option: [%s]\n", global_auth_tok->sig);
245                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
246                         goto out;
247                 } else
248                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
249         }
250 out:
251         return rc;
252 }
253
254 static void ecryptfs_init_mount_crypt_stat(
255         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
256 {
257         memset((void *)mount_crypt_stat, 0,
258                sizeof(struct ecryptfs_mount_crypt_stat));
259         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
260         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
261         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
262 }
263
264 /**
265  * ecryptfs_parse_options
266  * @sb: The ecryptfs super block
267  * @options: The options pased to the kernel
268  *
269  * Parse mount options:
270  * debug=N         - ecryptfs_verbosity level for debug output
271  * sig=XXX         - description(signature) of the key to use
272  *
273  * Returns the dentry object of the lower-level (lower/interposed)
274  * directory; We want to mount our stackable file system on top of
275  * that lower directory.
276  *
277  * The signature of the key to use must be the description of a key
278  * already in the keyring. Mounting will fail if the key can not be
279  * found.
280  *
281  * Returns zero on success; non-zero on error
282  */
283 static int ecryptfs_parse_options(struct super_block *sb, char *options)
284 {
285         char *p;
286         int rc = 0;
287         int sig_set = 0;
288         int cipher_name_set = 0;
289         int fn_cipher_name_set = 0;
290         int cipher_key_bytes;
291         int cipher_key_bytes_set = 0;
292         int fn_cipher_key_bytes;
293         int fn_cipher_key_bytes_set = 0;
294         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
295                 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
296         substring_t args[MAX_OPT_ARGS];
297         int token;
298         char *sig_src;
299         char *cipher_name_dst;
300         char *cipher_name_src;
301         char *fn_cipher_name_dst;
302         char *fn_cipher_name_src;
303         char *fnek_dst;
304         char *fnek_src;
305         char *cipher_key_bytes_src;
306         char *fn_cipher_key_bytes_src;
307
308         if (!options) {
309                 rc = -EINVAL;
310                 goto out;
311         }
312         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
313         while ((p = strsep(&options, ",")) != NULL) {
314                 if (!*p)
315                         continue;
316                 token = match_token(p, tokens, args);
317                 switch (token) {
318                 case ecryptfs_opt_sig:
319                 case ecryptfs_opt_ecryptfs_sig:
320                         sig_src = args[0].from;
321                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
322                                                           sig_src, 0);
323                         if (rc) {
324                                 printk(KERN_ERR "Error attempting to register "
325                                        "global sig; rc = [%d]\n", rc);
326                                 goto out;
327                         }
328                         sig_set = 1;
329                         break;
330                 case ecryptfs_opt_cipher:
331                 case ecryptfs_opt_ecryptfs_cipher:
332                         cipher_name_src = args[0].from;
333                         cipher_name_dst =
334                                 mount_crypt_stat->
335                                 global_default_cipher_name;
336                         strncpy(cipher_name_dst, cipher_name_src,
337                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
338                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
339                         cipher_name_set = 1;
340                         break;
341                 case ecryptfs_opt_ecryptfs_key_bytes:
342                         cipher_key_bytes_src = args[0].from;
343                         cipher_key_bytes =
344                                 (int)simple_strtol(cipher_key_bytes_src,
345                                                    &cipher_key_bytes_src, 0);
346                         mount_crypt_stat->global_default_cipher_key_size =
347                                 cipher_key_bytes;
348                         cipher_key_bytes_set = 1;
349                         break;
350                 case ecryptfs_opt_passthrough:
351                         mount_crypt_stat->flags |=
352                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
353                         break;
354                 case ecryptfs_opt_xattr_metadata:
355                         mount_crypt_stat->flags |=
356                                 ECRYPTFS_XATTR_METADATA_ENABLED;
357                         break;
358                 case ecryptfs_opt_encrypted_view:
359                         mount_crypt_stat->flags |=
360                                 ECRYPTFS_XATTR_METADATA_ENABLED;
361                         mount_crypt_stat->flags |=
362                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
363                         break;
364                 case ecryptfs_opt_fnek_sig:
365                         fnek_src = args[0].from;
366                         fnek_dst =
367                                 mount_crypt_stat->global_default_fnek_sig;
368                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
369                         mount_crypt_stat->global_default_fnek_sig[
370                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
371                         rc = ecryptfs_add_global_auth_tok(
372                                 mount_crypt_stat,
373                                 mount_crypt_stat->global_default_fnek_sig,
374                                 ECRYPTFS_AUTH_TOK_FNEK);
375                         if (rc) {
376                                 printk(KERN_ERR "Error attempting to register "
377                                        "global fnek sig [%s]; rc = [%d]\n",
378                                        mount_crypt_stat->global_default_fnek_sig,
379                                        rc);
380                                 goto out;
381                         }
382                         mount_crypt_stat->flags |=
383                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
384                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
385                         break;
386                 case ecryptfs_opt_fn_cipher:
387                         fn_cipher_name_src = args[0].from;
388                         fn_cipher_name_dst =
389                                 mount_crypt_stat->global_default_fn_cipher_name;
390                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
391                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
392                         mount_crypt_stat->global_default_fn_cipher_name[
393                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
394                         fn_cipher_name_set = 1;
395                         break;
396                 case ecryptfs_opt_fn_cipher_key_bytes:
397                         fn_cipher_key_bytes_src = args[0].from;
398                         fn_cipher_key_bytes =
399                                 (int)simple_strtol(fn_cipher_key_bytes_src,
400                                                    &fn_cipher_key_bytes_src, 0);
401                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
402                                 fn_cipher_key_bytes;
403                         fn_cipher_key_bytes_set = 1;
404                         break;
405                 case ecryptfs_opt_unlink_sigs:
406                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
407                         break;
408                 case ecryptfs_opt_err:
409                 default:
410                         printk(KERN_WARNING
411                                "%s: eCryptfs: unrecognized option [%s]\n",
412                                __func__, p);
413                 }
414         }
415         if (!sig_set) {
416                 rc = -EINVAL;
417                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
418                                 "auth tok signature as a mount "
419                                 "parameter; see the eCryptfs README\n");
420                 goto out;
421         }
422         if (!cipher_name_set) {
423                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
424
425                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
426                 strcpy(mount_crypt_stat->global_default_cipher_name,
427                        ECRYPTFS_DEFAULT_CIPHER);
428         }
429         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
430             && !fn_cipher_name_set)
431                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
432                        mount_crypt_stat->global_default_cipher_name);
433         if (!cipher_key_bytes_set)
434                 mount_crypt_stat->global_default_cipher_key_size = 0;
435         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
436             && !fn_cipher_key_bytes_set)
437                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
438                         mount_crypt_stat->global_default_cipher_key_size;
439         mutex_lock(&key_tfm_list_mutex);
440         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
441                                  NULL)) {
442                 rc = ecryptfs_add_new_key_tfm(
443                         NULL, mount_crypt_stat->global_default_cipher_name,
444                         mount_crypt_stat->global_default_cipher_key_size);
445                 if (rc) {
446                         printk(KERN_ERR "Error attempting to initialize "
447                                "cipher with name = [%s] and key size = [%td]; "
448                                "rc = [%d]\n",
449                                mount_crypt_stat->global_default_cipher_name,
450                                mount_crypt_stat->global_default_cipher_key_size,
451                                rc);
452                         rc = -EINVAL;
453                         mutex_unlock(&key_tfm_list_mutex);
454                         goto out;
455                 }
456         }
457         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
458             && !ecryptfs_tfm_exists(
459                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
460                 rc = ecryptfs_add_new_key_tfm(
461                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
462                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
463                 if (rc) {
464                         printk(KERN_ERR "Error attempting to initialize "
465                                "cipher with name = [%s] and key size = [%td]; "
466                                "rc = [%d]\n",
467                                mount_crypt_stat->global_default_fn_cipher_name,
468                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
469                                rc);
470                         rc = -EINVAL;
471                         mutex_unlock(&key_tfm_list_mutex);
472                         goto out;
473                 }
474         }
475         mutex_unlock(&key_tfm_list_mutex);
476         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
477         if (rc)
478                 printk(KERN_WARNING "One or more global auth toks could not "
479                        "properly register; rc = [%d]\n", rc);
480 out:
481         return rc;
482 }
483
484 struct kmem_cache *ecryptfs_sb_info_cache;
485
486 /**
487  * ecryptfs_fill_super
488  * @sb: The ecryptfs super block
489  * @raw_data: The options passed to mount
490  * @silent: Not used but required by function prototype
491  *
492  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
493  *
494  * Returns zero on success; non-zero otherwise
495  */
496 static int
497 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
498 {
499         int rc = 0;
500
501         /* Released in ecryptfs_put_super() */
502         ecryptfs_set_superblock_private(sb,
503                                         kmem_cache_zalloc(ecryptfs_sb_info_cache,
504                                                          GFP_KERNEL));
505         if (!ecryptfs_superblock_to_private(sb)) {
506                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
507                 rc = -ENOMEM;
508                 goto out;
509         }
510         sb->s_op = &ecryptfs_sops;
511         /* Released through deactivate_super(sb) from get_sb_nodev */
512         sb->s_root = d_alloc(NULL, &(const struct qstr) {
513                              .hash = 0,.name = "/",.len = 1});
514         if (!sb->s_root) {
515                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
516                 rc = -ENOMEM;
517                 goto out;
518         }
519         sb->s_root->d_op = &ecryptfs_dops;
520         sb->s_root->d_sb = sb;
521         sb->s_root->d_parent = sb->s_root;
522         /* Released in d_release when dput(sb->s_root) is called */
523         /* through deactivate_super(sb) from get_sb_nodev() */
524         ecryptfs_set_dentry_private(sb->s_root,
525                                     kmem_cache_zalloc(ecryptfs_dentry_info_cache,
526                                                      GFP_KERNEL));
527         if (!ecryptfs_dentry_to_private(sb->s_root)) {
528                 ecryptfs_printk(KERN_ERR,
529                                 "dentry_info_cache alloc failed\n");
530                 rc = -ENOMEM;
531                 goto out;
532         }
533         rc = 0;
534 out:
535         /* Should be able to rely on deactivate_super called from
536          * get_sb_nodev */
537         return rc;
538 }
539
540 /**
541  * ecryptfs_read_super
542  * @sb: The ecryptfs super block
543  * @dev_name: The path to mount over
544  *
545  * Read the super block of the lower filesystem, and use
546  * ecryptfs_interpose to create our initial inode and super block
547  * struct.
548  */
549 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
550 {
551         struct path path;
552         int rc;
553
554         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
555         if (rc) {
556                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
557                 goto out;
558         }
559         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
560         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
561         sb->s_blocksize = path.dentry->d_sb->s_blocksize;
562         ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
563         ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
564         rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
565         if (rc)
566                 goto out_free;
567         rc = 0;
568         goto out;
569 out_free:
570         path_put(&path);
571 out:
572         return rc;
573 }
574
575 /**
576  * ecryptfs_get_sb
577  * @fs_type
578  * @flags
579  * @dev_name: The path to mount over
580  * @raw_data: The options passed into the kernel
581  *
582  * The whole ecryptfs_get_sb process is broken into 4 functions:
583  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
584  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
585  *                        with as much information as it can before needing
586  *                        the lower filesystem.
587  * ecryptfs_read_super(): this accesses the lower filesystem and uses
588  *                        ecryptfs_interpolate to perform most of the linking
589  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
590  */
591 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
592                         const char *dev_name, void *raw_data,
593                         struct vfsmount *mnt)
594 {
595         int rc;
596         struct super_block *sb;
597
598         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
599         if (rc < 0) {
600                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
601                 goto out;
602         }
603         sb = mnt->mnt_sb;
604         rc = ecryptfs_parse_options(sb, raw_data);
605         if (rc) {
606                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
607                 goto out_abort;
608         }
609         rc = ecryptfs_read_super(sb, dev_name);
610         if (rc) {
611                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
612                 goto out_abort;
613         }
614         goto out;
615 out_abort:
616         dput(sb->s_root); /* aka mnt->mnt_root, as set by get_sb_nodev() */
617         deactivate_locked_super(sb);
618 out:
619         return rc;
620 }
621
622 /**
623  * ecryptfs_kill_block_super
624  * @sb: The ecryptfs super block
625  *
626  * Used to bring the superblock down and free the private data.
627  * Private data is free'd in ecryptfs_put_super()
628  */
629 static void ecryptfs_kill_block_super(struct super_block *sb)
630 {
631         generic_shutdown_super(sb);
632 }
633
634 static struct file_system_type ecryptfs_fs_type = {
635         .owner = THIS_MODULE,
636         .name = "ecryptfs",
637         .get_sb = ecryptfs_get_sb,
638         .kill_sb = ecryptfs_kill_block_super,
639         .fs_flags = 0
640 };
641
642 /**
643  * inode_info_init_once
644  *
645  * Initializes the ecryptfs_inode_info_cache when it is created
646  */
647 static void
648 inode_info_init_once(void *vptr)
649 {
650         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
651
652         inode_init_once(&ei->vfs_inode);
653 }
654
655 static struct ecryptfs_cache_info {
656         struct kmem_cache **cache;
657         const char *name;
658         size_t size;
659         void (*ctor)(void *obj);
660 } ecryptfs_cache_infos[] = {
661         {
662                 .cache = &ecryptfs_auth_tok_list_item_cache,
663                 .name = "ecryptfs_auth_tok_list_item",
664                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
665         },
666         {
667                 .cache = &ecryptfs_file_info_cache,
668                 .name = "ecryptfs_file_cache",
669                 .size = sizeof(struct ecryptfs_file_info),
670         },
671         {
672                 .cache = &ecryptfs_dentry_info_cache,
673                 .name = "ecryptfs_dentry_info_cache",
674                 .size = sizeof(struct ecryptfs_dentry_info),
675         },
676         {
677                 .cache = &ecryptfs_inode_info_cache,
678                 .name = "ecryptfs_inode_cache",
679                 .size = sizeof(struct ecryptfs_inode_info),
680                 .ctor = inode_info_init_once,
681         },
682         {
683                 .cache = &ecryptfs_sb_info_cache,
684                 .name = "ecryptfs_sb_cache",
685                 .size = sizeof(struct ecryptfs_sb_info),
686         },
687         {
688                 .cache = &ecryptfs_header_cache_1,
689                 .name = "ecryptfs_headers_1",
690                 .size = PAGE_CACHE_SIZE,
691         },
692         {
693                 .cache = &ecryptfs_header_cache_2,
694                 .name = "ecryptfs_headers_2",
695                 .size = PAGE_CACHE_SIZE,
696         },
697         {
698                 .cache = &ecryptfs_xattr_cache,
699                 .name = "ecryptfs_xattr_cache",
700                 .size = PAGE_CACHE_SIZE,
701         },
702         {
703                 .cache = &ecryptfs_key_record_cache,
704                 .name = "ecryptfs_key_record_cache",
705                 .size = sizeof(struct ecryptfs_key_record),
706         },
707         {
708                 .cache = &ecryptfs_key_sig_cache,
709                 .name = "ecryptfs_key_sig_cache",
710                 .size = sizeof(struct ecryptfs_key_sig),
711         },
712         {
713                 .cache = &ecryptfs_global_auth_tok_cache,
714                 .name = "ecryptfs_global_auth_tok_cache",
715                 .size = sizeof(struct ecryptfs_global_auth_tok),
716         },
717         {
718                 .cache = &ecryptfs_key_tfm_cache,
719                 .name = "ecryptfs_key_tfm_cache",
720                 .size = sizeof(struct ecryptfs_key_tfm),
721         },
722         {
723                 .cache = &ecryptfs_open_req_cache,
724                 .name = "ecryptfs_open_req_cache",
725                 .size = sizeof(struct ecryptfs_open_req),
726         },
727 };
728
729 static void ecryptfs_free_kmem_caches(void)
730 {
731         int i;
732
733         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
734                 struct ecryptfs_cache_info *info;
735
736                 info = &ecryptfs_cache_infos[i];
737                 if (*(info->cache))
738                         kmem_cache_destroy(*(info->cache));
739         }
740 }
741
742 /**
743  * ecryptfs_init_kmem_caches
744  *
745  * Returns zero on success; non-zero otherwise
746  */
747 static int ecryptfs_init_kmem_caches(void)
748 {
749         int i;
750
751         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
752                 struct ecryptfs_cache_info *info;
753
754                 info = &ecryptfs_cache_infos[i];
755                 *(info->cache) = kmem_cache_create(info->name, info->size,
756                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
757                 if (!*(info->cache)) {
758                         ecryptfs_free_kmem_caches();
759                         ecryptfs_printk(KERN_WARNING, "%s: "
760                                         "kmem_cache_create failed\n",
761                                         info->name);
762                         return -ENOMEM;
763                 }
764         }
765         return 0;
766 }
767
768 static struct kobject *ecryptfs_kobj;
769
770 static ssize_t version_show(struct kobject *kobj,
771                             struct kobj_attribute *attr, char *buff)
772 {
773         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
774 }
775
776 static struct kobj_attribute version_attr = __ATTR_RO(version);
777
778 static struct attribute *attributes[] = {
779         &version_attr.attr,
780         NULL,
781 };
782
783 static struct attribute_group attr_group = {
784         .attrs = attributes,
785 };
786
787 static int do_sysfs_registration(void)
788 {
789         int rc;
790
791         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
792         if (!ecryptfs_kobj) {
793                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
794                 rc = -ENOMEM;
795                 goto out;
796         }
797         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
798         if (rc) {
799                 printk(KERN_ERR
800                        "Unable to create ecryptfs version attributes\n");
801                 kobject_put(ecryptfs_kobj);
802         }
803 out:
804         return rc;
805 }
806
807 static void do_sysfs_unregistration(void)
808 {
809         sysfs_remove_group(ecryptfs_kobj, &attr_group);
810         kobject_put(ecryptfs_kobj);
811 }
812
813 static int __init ecryptfs_init(void)
814 {
815         int rc;
816
817         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
818                 rc = -EINVAL;
819                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
820                                 "larger than the host's page size, and so "
821                                 "eCryptfs cannot run on this system. The "
822                                 "default eCryptfs extent size is [%d] bytes; "
823                                 "the page size is [%d] bytes.\n",
824                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE);
825                 goto out;
826         }
827         rc = ecryptfs_init_kmem_caches();
828         if (rc) {
829                 printk(KERN_ERR
830                        "Failed to allocate one or more kmem_cache objects\n");
831                 goto out;
832         }
833         rc = register_filesystem(&ecryptfs_fs_type);
834         if (rc) {
835                 printk(KERN_ERR "Failed to register filesystem\n");
836                 goto out_free_kmem_caches;
837         }
838         rc = do_sysfs_registration();
839         if (rc) {
840                 printk(KERN_ERR "sysfs registration failed\n");
841                 goto out_unregister_filesystem;
842         }
843         rc = ecryptfs_init_kthread();
844         if (rc) {
845                 printk(KERN_ERR "%s: kthread initialization failed; "
846                        "rc = [%d]\n", __func__, rc);
847                 goto out_do_sysfs_unregistration;
848         }
849         rc = ecryptfs_init_messaging();
850         if (rc) {
851                 printk(KERN_ERR "Failure occured while attempting to "
852                                 "initialize the communications channel to "
853                                 "ecryptfsd\n");
854                 goto out_destroy_kthread;
855         }
856         rc = ecryptfs_init_crypto();
857         if (rc) {
858                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
859                        "rc = [%d]\n", rc);
860                 goto out_release_messaging;
861         }
862         if (ecryptfs_verbosity > 0)
863                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
864                         "will be written to the syslog!\n", ecryptfs_verbosity);
865
866         goto out;
867 out_release_messaging:
868         ecryptfs_release_messaging();
869 out_destroy_kthread:
870         ecryptfs_destroy_kthread();
871 out_do_sysfs_unregistration:
872         do_sysfs_unregistration();
873 out_unregister_filesystem:
874         unregister_filesystem(&ecryptfs_fs_type);
875 out_free_kmem_caches:
876         ecryptfs_free_kmem_caches();
877 out:
878         return rc;
879 }
880
881 static void __exit ecryptfs_exit(void)
882 {
883         int rc;
884
885         rc = ecryptfs_destroy_crypto();
886         if (rc)
887                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
888                        "rc = [%d]\n", rc);
889         ecryptfs_release_messaging();
890         ecryptfs_destroy_kthread();
891         do_sysfs_unregistration();
892         unregister_filesystem(&ecryptfs_fs_type);
893         ecryptfs_free_kmem_caches();
894 }
895
896 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
897 MODULE_DESCRIPTION("eCryptfs");
898
899 MODULE_LICENSE("GPL");
900
901 module_init(ecryptfs_init)
902 module_exit(ecryptfs_exit)