c6ac85d6c701f5b7d82e069c9a3f82a67a51d0b3
[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 <linux/ima.h>
39 #include "ecryptfs_kernel.h"
40
41 /**
42  * Module parameter that defines the ecryptfs_verbosity level.
43  */
44 int ecryptfs_verbosity = 0;
45
46 module_param(ecryptfs_verbosity, int, 0);
47 MODULE_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  */
54 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
55
56 module_param(ecryptfs_message_buf_len, uint, 0);
57 MODULE_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  */
66 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
67
68 module_param(ecryptfs_message_wait_timeout, long, 0);
69 MODULE_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  */
79 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
80
81 module_param(ecryptfs_number_of_users, uint, 0);
82 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
83                  "concurrent users of eCryptfs");
84
85 void __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_persistent_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  * persistent file struct and associates it with the eCryptfs
107  * inode. When the eCryptfs inode is destroyed, the file is closed.
108  *
109  * The persistent file will be opened with read/write permissions, if
110  * possible. Otherwise, it is opened read-only.
111  *
112  * This function does nothing if a lower persistent file is already
113  * associated with the eCryptfs inode.
114  *
115  * Returns zero on success; non-zero otherwise
116  */
117 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
118 {
119         const struct cred *cred = current_cred();
120         struct ecryptfs_inode_info *inode_info =
121                 ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
122         int opened_lower_file = 0;
123         int rc = 0;
124
125         mutex_lock(&inode_info->lower_file_mutex);
126         if (!inode_info->lower_file) {
127                 struct dentry *lower_dentry;
128                 struct vfsmount *lower_mnt =
129                         ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
130
131                 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
132                 rc = ecryptfs_privileged_open(&inode_info->lower_file,
133                                               lower_dentry, lower_mnt, cred);
134                 if (rc) {
135                         printk(KERN_ERR "Error opening lower persistent file "
136                                "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
137                                "rc = [%d]\n", lower_dentry, lower_mnt, rc);
138                         inode_info->lower_file = NULL;
139                 } else
140                         opened_lower_file = 1;
141         }
142         mutex_unlock(&inode_info->lower_file_mutex);
143         if (opened_lower_file)
144                 ima_counts_get(inode_info->lower_file);
145         return rc;
146 }
147
148 /**
149  * ecryptfs_interpose
150  * @lower_dentry: Existing dentry in the lower filesystem
151  * @dentry: ecryptfs' dentry
152  * @sb: ecryptfs's super_block
153  * @flags: flags to govern behavior of interpose procedure
154  *
155  * Interposes upper and lower dentries.
156  *
157  * Returns zero on success; non-zero otherwise
158  */
159 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry,
160                        struct super_block *sb, u32 flags)
161 {
162         struct inode *lower_inode;
163         struct inode *inode;
164         int rc = 0;
165
166         lower_inode = lower_dentry->d_inode;
167         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) {
168                 rc = -EXDEV;
169                 goto out;
170         }
171         if (!igrab(lower_inode)) {
172                 rc = -ESTALE;
173                 goto out;
174         }
175         inode = iget5_locked(sb, (unsigned long)lower_inode,
176                              ecryptfs_inode_test, ecryptfs_inode_set,
177                              lower_inode);
178         if (!inode) {
179                 rc = -EACCES;
180                 iput(lower_inode);
181                 goto out;
182         }
183         if (inode->i_state & I_NEW)
184                 unlock_new_inode(inode);
185         else
186                 iput(lower_inode);
187         if (S_ISLNK(lower_inode->i_mode))
188                 inode->i_op = &ecryptfs_symlink_iops;
189         else if (S_ISDIR(lower_inode->i_mode))
190                 inode->i_op = &ecryptfs_dir_iops;
191         if (S_ISDIR(lower_inode->i_mode))
192                 inode->i_fop = &ecryptfs_dir_fops;
193         if (special_file(lower_inode->i_mode))
194                 init_special_inode(inode, lower_inode->i_mode,
195                                    lower_inode->i_rdev);
196         dentry->d_op = &ecryptfs_dops;
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         if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD)
202                 d_add(dentry, inode);
203         else
204                 d_instantiate(dentry, inode);
205 out:
206         return rc;
207 }
208
209 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
210        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
211        ecryptfs_opt_ecryptfs_key_bytes,
212        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
213        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
214        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
215        ecryptfs_opt_unlink_sigs, ecryptfs_opt_err };
216
217 static const match_table_t tokens = {
218         {ecryptfs_opt_sig, "sig=%s"},
219         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
220         {ecryptfs_opt_cipher, "cipher=%s"},
221         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
222         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
223         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
224         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
225         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
226         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
227         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
228         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
229         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
230         {ecryptfs_opt_err, NULL}
231 };
232
233 static int ecryptfs_init_global_auth_toks(
234         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
235 {
236         struct ecryptfs_global_auth_tok *global_auth_tok;
237         int rc = 0;
238
239         list_for_each_entry(global_auth_tok,
240                             &mount_crypt_stat->global_auth_tok_list,
241                             mount_crypt_stat_list) {
242                 rc = ecryptfs_keyring_auth_tok_for_sig(
243                         &global_auth_tok->global_auth_tok_key,
244                         &global_auth_tok->global_auth_tok,
245                         global_auth_tok->sig);
246                 if (rc) {
247                         printk(KERN_ERR "Could not find valid key in user "
248                                "session keyring for sig specified in mount "
249                                "option: [%s]\n", global_auth_tok->sig);
250                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
251                         goto out;
252                 } else
253                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
254         }
255 out:
256         return rc;
257 }
258
259 static void ecryptfs_init_mount_crypt_stat(
260         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
261 {
262         memset((void *)mount_crypt_stat, 0,
263                sizeof(struct ecryptfs_mount_crypt_stat));
264         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
265         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
266         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
267 }
268
269 /**
270  * ecryptfs_parse_options
271  * @sb: The ecryptfs super block
272  * @options: The options pased to the kernel
273  *
274  * Parse mount options:
275  * debug=N         - ecryptfs_verbosity level for debug output
276  * sig=XXX         - description(signature) of the key to use
277  *
278  * Returns the dentry object of the lower-level (lower/interposed)
279  * directory; We want to mount our stackable file system on top of
280  * that lower directory.
281  *
282  * The signature of the key to use must be the description of a key
283  * already in the keyring. Mounting will fail if the key can not be
284  * found.
285  *
286  * Returns zero on success; non-zero on error
287  */
288 static int ecryptfs_parse_options(struct super_block *sb, char *options)
289 {
290         char *p;
291         int rc = 0;
292         int sig_set = 0;
293         int cipher_name_set = 0;
294         int fn_cipher_name_set = 0;
295         int cipher_key_bytes;
296         int cipher_key_bytes_set = 0;
297         int fn_cipher_key_bytes;
298         int fn_cipher_key_bytes_set = 0;
299         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
300                 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
301         substring_t args[MAX_OPT_ARGS];
302         int token;
303         char *sig_src;
304         char *cipher_name_dst;
305         char *cipher_name_src;
306         char *fn_cipher_name_dst;
307         char *fn_cipher_name_src;
308         char *fnek_dst;
309         char *fnek_src;
310         char *cipher_key_bytes_src;
311         char *fn_cipher_key_bytes_src;
312
313         if (!options) {
314                 rc = -EINVAL;
315                 goto out;
316         }
317         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
318         while ((p = strsep(&options, ",")) != NULL) {
319                 if (!*p)
320                         continue;
321                 token = match_token(p, tokens, args);
322                 switch (token) {
323                 case ecryptfs_opt_sig:
324                 case ecryptfs_opt_ecryptfs_sig:
325                         sig_src = args[0].from;
326                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
327                                                           sig_src, 0);
328                         if (rc) {
329                                 printk(KERN_ERR "Error attempting to register "
330                                        "global sig; rc = [%d]\n", rc);
331                                 goto out;
332                         }
333                         sig_set = 1;
334                         break;
335                 case ecryptfs_opt_cipher:
336                 case ecryptfs_opt_ecryptfs_cipher:
337                         cipher_name_src = args[0].from;
338                         cipher_name_dst =
339                                 mount_crypt_stat->
340                                 global_default_cipher_name;
341                         strncpy(cipher_name_dst, cipher_name_src,
342                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
343                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
344                         cipher_name_set = 1;
345                         break;
346                 case ecryptfs_opt_ecryptfs_key_bytes:
347                         cipher_key_bytes_src = args[0].from;
348                         cipher_key_bytes =
349                                 (int)simple_strtol(cipher_key_bytes_src,
350                                                    &cipher_key_bytes_src, 0);
351                         mount_crypt_stat->global_default_cipher_key_size =
352                                 cipher_key_bytes;
353                         cipher_key_bytes_set = 1;
354                         break;
355                 case ecryptfs_opt_passthrough:
356                         mount_crypt_stat->flags |=
357                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
358                         break;
359                 case ecryptfs_opt_xattr_metadata:
360                         mount_crypt_stat->flags |=
361                                 ECRYPTFS_XATTR_METADATA_ENABLED;
362                         break;
363                 case ecryptfs_opt_encrypted_view:
364                         mount_crypt_stat->flags |=
365                                 ECRYPTFS_XATTR_METADATA_ENABLED;
366                         mount_crypt_stat->flags |=
367                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
368                         break;
369                 case ecryptfs_opt_fnek_sig:
370                         fnek_src = args[0].from;
371                         fnek_dst =
372                                 mount_crypt_stat->global_default_fnek_sig;
373                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
374                         mount_crypt_stat->global_default_fnek_sig[
375                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
376                         rc = ecryptfs_add_global_auth_tok(
377                                 mount_crypt_stat,
378                                 mount_crypt_stat->global_default_fnek_sig,
379                                 ECRYPTFS_AUTH_TOK_FNEK);
380                         if (rc) {
381                                 printk(KERN_ERR "Error attempting to register "
382                                        "global fnek sig [%s]; rc = [%d]\n",
383                                        mount_crypt_stat->global_default_fnek_sig,
384                                        rc);
385                                 goto out;
386                         }
387                         mount_crypt_stat->flags |=
388                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
389                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
390                         break;
391                 case ecryptfs_opt_fn_cipher:
392                         fn_cipher_name_src = args[0].from;
393                         fn_cipher_name_dst =
394                                 mount_crypt_stat->global_default_fn_cipher_name;
395                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
396                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
397                         mount_crypt_stat->global_default_fn_cipher_name[
398                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
399                         fn_cipher_name_set = 1;
400                         break;
401                 case ecryptfs_opt_fn_cipher_key_bytes:
402                         fn_cipher_key_bytes_src = args[0].from;
403                         fn_cipher_key_bytes =
404                                 (int)simple_strtol(fn_cipher_key_bytes_src,
405                                                    &fn_cipher_key_bytes_src, 0);
406                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
407                                 fn_cipher_key_bytes;
408                         fn_cipher_key_bytes_set = 1;
409                         break;
410                 case ecryptfs_opt_unlink_sigs:
411                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
412                         break;
413                 case ecryptfs_opt_err:
414                 default:
415                         printk(KERN_WARNING
416                                "%s: eCryptfs: unrecognized option [%s]\n",
417                                __func__, p);
418                 }
419         }
420         if (!sig_set) {
421                 rc = -EINVAL;
422                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
423                                 "auth tok signature as a mount "
424                                 "parameter; see the eCryptfs README\n");
425                 goto out;
426         }
427         if (!cipher_name_set) {
428                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
429
430                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
431                 strcpy(mount_crypt_stat->global_default_cipher_name,
432                        ECRYPTFS_DEFAULT_CIPHER);
433         }
434         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
435             && !fn_cipher_name_set)
436                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
437                        mount_crypt_stat->global_default_cipher_name);
438         if (!cipher_key_bytes_set)
439                 mount_crypt_stat->global_default_cipher_key_size = 0;
440         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
441             && !fn_cipher_key_bytes_set)
442                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
443                         mount_crypt_stat->global_default_cipher_key_size;
444         mutex_lock(&key_tfm_list_mutex);
445         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
446                                  NULL)) {
447                 rc = ecryptfs_add_new_key_tfm(
448                         NULL, mount_crypt_stat->global_default_cipher_name,
449                         mount_crypt_stat->global_default_cipher_key_size);
450                 if (rc) {
451                         printk(KERN_ERR "Error attempting to initialize "
452                                "cipher with name = [%s] and key size = [%td]; "
453                                "rc = [%d]\n",
454                                mount_crypt_stat->global_default_cipher_name,
455                                mount_crypt_stat->global_default_cipher_key_size,
456                                rc);
457                         rc = -EINVAL;
458                         mutex_unlock(&key_tfm_list_mutex);
459                         goto out;
460                 }
461         }
462         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
463             && !ecryptfs_tfm_exists(
464                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
465                 rc = ecryptfs_add_new_key_tfm(
466                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
467                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
468                 if (rc) {
469                         printk(KERN_ERR "Error attempting to initialize "
470                                "cipher with name = [%s] and key size = [%td]; "
471                                "rc = [%d]\n",
472                                mount_crypt_stat->global_default_fn_cipher_name,
473                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
474                                rc);
475                         rc = -EINVAL;
476                         mutex_unlock(&key_tfm_list_mutex);
477                         goto out;
478                 }
479         }
480         mutex_unlock(&key_tfm_list_mutex);
481         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
482         if (rc)
483                 printk(KERN_WARNING "One or more global auth toks could not "
484                        "properly register; rc = [%d]\n", rc);
485 out:
486         return rc;
487 }
488
489 struct kmem_cache *ecryptfs_sb_info_cache;
490
491 /**
492  * ecryptfs_fill_super
493  * @sb: The ecryptfs super block
494  * @raw_data: The options passed to mount
495  * @silent: Not used but required by function prototype
496  *
497  * Sets up what we can of the sb, rest is done in ecryptfs_read_super
498  *
499  * Returns zero on success; non-zero otherwise
500  */
501 static int
502 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent)
503 {
504         int rc = 0;
505
506         /* Released in ecryptfs_put_super() */
507         ecryptfs_set_superblock_private(sb,
508                                         kmem_cache_zalloc(ecryptfs_sb_info_cache,
509                                                          GFP_KERNEL));
510         if (!ecryptfs_superblock_to_private(sb)) {
511                 ecryptfs_printk(KERN_WARNING, "Out of memory\n");
512                 rc = -ENOMEM;
513                 goto out;
514         }
515         sb->s_op = &ecryptfs_sops;
516         /* Released through deactivate_super(sb) from get_sb_nodev */
517         sb->s_root = d_alloc(NULL, &(const struct qstr) {
518                              .hash = 0,.name = "/",.len = 1});
519         if (!sb->s_root) {
520                 ecryptfs_printk(KERN_ERR, "d_alloc failed\n");
521                 rc = -ENOMEM;
522                 goto out;
523         }
524         sb->s_root->d_op = &ecryptfs_dops;
525         sb->s_root->d_sb = sb;
526         sb->s_root->d_parent = sb->s_root;
527         /* Released in d_release when dput(sb->s_root) is called */
528         /* through deactivate_super(sb) from get_sb_nodev() */
529         ecryptfs_set_dentry_private(sb->s_root,
530                                     kmem_cache_zalloc(ecryptfs_dentry_info_cache,
531                                                      GFP_KERNEL));
532         if (!ecryptfs_dentry_to_private(sb->s_root)) {
533                 ecryptfs_printk(KERN_ERR,
534                                 "dentry_info_cache alloc failed\n");
535                 rc = -ENOMEM;
536                 goto out;
537         }
538         rc = 0;
539 out:
540         /* Should be able to rely on deactivate_super called from
541          * get_sb_nodev */
542         return rc;
543 }
544
545 /**
546  * ecryptfs_read_super
547  * @sb: The ecryptfs super block
548  * @dev_name: The path to mount over
549  *
550  * Read the super block of the lower filesystem, and use
551  * ecryptfs_interpose to create our initial inode and super block
552  * struct.
553  */
554 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
555 {
556         struct path path;
557         int rc;
558
559         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
560         if (rc) {
561                 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n");
562                 goto out;
563         }
564         ecryptfs_set_superblock_lower(sb, path.dentry->d_sb);
565         sb->s_maxbytes = path.dentry->d_sb->s_maxbytes;
566         sb->s_blocksize = path.dentry->d_sb->s_blocksize;
567         ecryptfs_set_dentry_lower(sb->s_root, path.dentry);
568         ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt);
569         rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0);
570         if (rc)
571                 goto out_free;
572         rc = 0;
573         goto out;
574 out_free:
575         path_put(&path);
576 out:
577         return rc;
578 }
579
580 /**
581  * ecryptfs_get_sb
582  * @fs_type
583  * @flags
584  * @dev_name: The path to mount over
585  * @raw_data: The options passed into the kernel
586  *
587  * The whole ecryptfs_get_sb process is broken into 4 functions:
588  * ecryptfs_parse_options(): handle options passed to ecryptfs, if any
589  * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block
590  *                        with as much information as it can before needing
591  *                        the lower filesystem.
592  * ecryptfs_read_super(): this accesses the lower filesystem and uses
593  *                        ecryptfs_interpolate to perform most of the linking
594  * ecryptfs_interpolate(): links the lower filesystem into ecryptfs
595  */
596 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags,
597                         const char *dev_name, void *raw_data,
598                         struct vfsmount *mnt)
599 {
600         int rc;
601         struct super_block *sb;
602
603         rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt);
604         if (rc < 0) {
605                 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc);
606                 goto out;
607         }
608         sb = mnt->mnt_sb;
609         rc = ecryptfs_parse_options(sb, raw_data);
610         if (rc) {
611                 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc);
612                 goto out_abort;
613         }
614         rc = ecryptfs_read_super(sb, dev_name);
615         if (rc) {
616                 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc);
617                 goto out_abort;
618         }
619         goto out;
620 out_abort:
621         dput(sb->s_root); /* aka mnt->mnt_root, as set by get_sb_nodev() */
622         deactivate_locked_super(sb);
623 out:
624         return rc;
625 }
626
627 /**
628  * ecryptfs_kill_block_super
629  * @sb: The ecryptfs super block
630  *
631  * Used to bring the superblock down and free the private data.
632  * Private data is free'd in ecryptfs_put_super()
633  */
634 static void ecryptfs_kill_block_super(struct super_block *sb)
635 {
636         generic_shutdown_super(sb);
637 }
638
639 static struct file_system_type ecryptfs_fs_type = {
640         .owner = THIS_MODULE,
641         .name = "ecryptfs",
642         .get_sb = ecryptfs_get_sb,
643         .kill_sb = ecryptfs_kill_block_super,
644         .fs_flags = 0
645 };
646
647 /**
648  * inode_info_init_once
649  *
650  * Initializes the ecryptfs_inode_info_cache when it is created
651  */
652 static void
653 inode_info_init_once(void *vptr)
654 {
655         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
656
657         inode_init_once(&ei->vfs_inode);
658 }
659
660 static struct ecryptfs_cache_info {
661         struct kmem_cache **cache;
662         const char *name;
663         size_t size;
664         void (*ctor)(void *obj);
665 } ecryptfs_cache_infos[] = {
666         {
667                 .cache = &ecryptfs_auth_tok_list_item_cache,
668                 .name = "ecryptfs_auth_tok_list_item",
669                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
670         },
671         {
672                 .cache = &ecryptfs_file_info_cache,
673                 .name = "ecryptfs_file_cache",
674                 .size = sizeof(struct ecryptfs_file_info),
675         },
676         {
677                 .cache = &ecryptfs_dentry_info_cache,
678                 .name = "ecryptfs_dentry_info_cache",
679                 .size = sizeof(struct ecryptfs_dentry_info),
680         },
681         {
682                 .cache = &ecryptfs_inode_info_cache,
683                 .name = "ecryptfs_inode_cache",
684                 .size = sizeof(struct ecryptfs_inode_info),
685                 .ctor = inode_info_init_once,
686         },
687         {
688                 .cache = &ecryptfs_sb_info_cache,
689                 .name = "ecryptfs_sb_cache",
690                 .size = sizeof(struct ecryptfs_sb_info),
691         },
692         {
693                 .cache = &ecryptfs_header_cache_1,
694                 .name = "ecryptfs_headers_1",
695                 .size = PAGE_CACHE_SIZE,
696         },
697         {
698                 .cache = &ecryptfs_header_cache_2,
699                 .name = "ecryptfs_headers_2",
700                 .size = PAGE_CACHE_SIZE,
701         },
702         {
703                 .cache = &ecryptfs_xattr_cache,
704                 .name = "ecryptfs_xattr_cache",
705                 .size = PAGE_CACHE_SIZE,
706         },
707         {
708                 .cache = &ecryptfs_key_record_cache,
709                 .name = "ecryptfs_key_record_cache",
710                 .size = sizeof(struct ecryptfs_key_record),
711         },
712         {
713                 .cache = &ecryptfs_key_sig_cache,
714                 .name = "ecryptfs_key_sig_cache",
715                 .size = sizeof(struct ecryptfs_key_sig),
716         },
717         {
718                 .cache = &ecryptfs_global_auth_tok_cache,
719                 .name = "ecryptfs_global_auth_tok_cache",
720                 .size = sizeof(struct ecryptfs_global_auth_tok),
721         },
722         {
723                 .cache = &ecryptfs_key_tfm_cache,
724                 .name = "ecryptfs_key_tfm_cache",
725                 .size = sizeof(struct ecryptfs_key_tfm),
726         },
727         {
728                 .cache = &ecryptfs_open_req_cache,
729                 .name = "ecryptfs_open_req_cache",
730                 .size = sizeof(struct ecryptfs_open_req),
731         },
732 };
733
734 static void ecryptfs_free_kmem_caches(void)
735 {
736         int i;
737
738         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
739                 struct ecryptfs_cache_info *info;
740
741                 info = &ecryptfs_cache_infos[i];
742                 if (*(info->cache))
743                         kmem_cache_destroy(*(info->cache));
744         }
745 }
746
747 /**
748  * ecryptfs_init_kmem_caches
749  *
750  * Returns zero on success; non-zero otherwise
751  */
752 static int ecryptfs_init_kmem_caches(void)
753 {
754         int i;
755
756         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
757                 struct ecryptfs_cache_info *info;
758
759                 info = &ecryptfs_cache_infos[i];
760                 *(info->cache) = kmem_cache_create(info->name, info->size,
761                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
762                 if (!*(info->cache)) {
763                         ecryptfs_free_kmem_caches();
764                         ecryptfs_printk(KERN_WARNING, "%s: "
765                                         "kmem_cache_create failed\n",
766                                         info->name);
767                         return -ENOMEM;
768                 }
769         }
770         return 0;
771 }
772
773 static struct kobject *ecryptfs_kobj;
774
775 static ssize_t version_show(struct kobject *kobj,
776                             struct kobj_attribute *attr, char *buff)
777 {
778         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
779 }
780
781 static struct kobj_attribute version_attr = __ATTR_RO(version);
782
783 static struct attribute *attributes[] = {
784         &version_attr.attr,
785         NULL,
786 };
787
788 static struct attribute_group attr_group = {
789         .attrs = attributes,
790 };
791
792 static int do_sysfs_registration(void)
793 {
794         int rc;
795
796         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
797         if (!ecryptfs_kobj) {
798                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
799                 rc = -ENOMEM;
800                 goto out;
801         }
802         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
803         if (rc) {
804                 printk(KERN_ERR
805                        "Unable to create ecryptfs version attributes\n");
806                 kobject_put(ecryptfs_kobj);
807         }
808 out:
809         return rc;
810 }
811
812 static void do_sysfs_unregistration(void)
813 {
814         sysfs_remove_group(ecryptfs_kobj, &attr_group);
815         kobject_put(ecryptfs_kobj);
816 }
817
818 static int __init ecryptfs_init(void)
819 {
820         int rc;
821
822         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
823                 rc = -EINVAL;
824                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
825                                 "larger than the host's page size, and so "
826                                 "eCryptfs cannot run on this system. The "
827                                 "default eCryptfs extent size is [%d] bytes; "
828                                 "the page size is [%d] bytes.\n",
829                                 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_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 = register_filesystem(&ecryptfs_fs_type);
839         if (rc) {
840                 printk(KERN_ERR "Failed to register filesystem\n");
841                 goto out_free_kmem_caches;
842         }
843         rc = do_sysfs_registration();
844         if (rc) {
845                 printk(KERN_ERR "sysfs registration failed\n");
846                 goto out_unregister_filesystem;
847         }
848         rc = ecryptfs_init_kthread();
849         if (rc) {
850                 printk(KERN_ERR "%s: kthread initialization failed; "
851                        "rc = [%d]\n", __func__, rc);
852                 goto out_do_sysfs_unregistration;
853         }
854         rc = ecryptfs_init_messaging();
855         if (rc) {
856                 printk(KERN_ERR "Failure occured while attempting to "
857                                 "initialize the communications channel to "
858                                 "ecryptfsd\n");
859                 goto out_destroy_kthread;
860         }
861         rc = ecryptfs_init_crypto();
862         if (rc) {
863                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
864                        "rc = [%d]\n", rc);
865                 goto out_release_messaging;
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;
872 out_release_messaging:
873         ecryptfs_release_messaging();
874 out_destroy_kthread:
875         ecryptfs_destroy_kthread();
876 out_do_sysfs_unregistration:
877         do_sysfs_unregistration();
878 out_unregister_filesystem:
879         unregister_filesystem(&ecryptfs_fs_type);
880 out_free_kmem_caches:
881         ecryptfs_free_kmem_caches();
882 out:
883         return rc;
884 }
885
886 static 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
901 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
902 MODULE_DESCRIPTION("eCryptfs");
903
904 MODULE_LICENSE("GPL");
905
906 module_init(ecryptfs_init)
907 module_exit(ecryptfs_exit)