switch open-coded instances of d_make_root() to new helper
[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/slab.h>
39 #include <linux/magic.h>
40 #include "ecryptfs_kernel.h"
41
42 /**
43  * Module parameter that defines the ecryptfs_verbosity level.
44  */
45 int ecryptfs_verbosity = 0;
46
47 module_param(ecryptfs_verbosity, int, 0);
48 MODULE_PARM_DESC(ecryptfs_verbosity,
49                  "Initial verbosity level (0 or 1; defaults to "
50                  "0, which is Quiet)");
51
52 /**
53  * Module parameter that defines the number of message buffer elements
54  */
55 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
56
57 module_param(ecryptfs_message_buf_len, uint, 0);
58 MODULE_PARM_DESC(ecryptfs_message_buf_len,
59                  "Number of message buffer elements");
60
61 /**
62  * Module parameter that defines the maximum guaranteed amount of time to wait
63  * for a response from ecryptfsd.  The actual sleep time will be, more than
64  * likely, a small amount greater than this specified value, but only less if
65  * the message successfully arrives.
66  */
67 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
68
69 module_param(ecryptfs_message_wait_timeout, long, 0);
70 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
71                  "Maximum number of seconds that an operation will "
72                  "sleep while waiting for a message response from "
73                  "userspace");
74
75 /**
76  * Module parameter that is an estimate of the maximum number of users
77  * that will be concurrently using eCryptfs. Set this to the right
78  * value to balance performance and memory use.
79  */
80 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
81
82 module_param(ecryptfs_number_of_users, uint, 0);
83 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
84                  "concurrent users of eCryptfs");
85
86 void __ecryptfs_printk(const char *fmt, ...)
87 {
88         va_list args;
89         va_start(args, fmt);
90         if (fmt[1] == '7') { /* KERN_DEBUG */
91                 if (ecryptfs_verbosity >= 1)
92                         vprintk(fmt, args);
93         } else
94                 vprintk(fmt, args);
95         va_end(args);
96 }
97
98 /**
99  * ecryptfs_init_lower_file
100  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
101  *                   the lower dentry and the lower mount set
102  *
103  * eCryptfs only ever keeps a single open file for every lower
104  * inode. All I/O operations to the lower inode occur through that
105  * file. When the first eCryptfs dentry that interposes with the first
106  * lower dentry for that inode is created, this function creates the
107  * lower file struct and associates it with the eCryptfs
108  * inode. When all eCryptfs files associated with the inode are released, the
109  * file is closed.
110  *
111  * The lower file will be opened with read/write permissions, if
112  * possible. Otherwise, it is opened read-only.
113  *
114  * This function does nothing if a lower file is already
115  * associated with the eCryptfs inode.
116  *
117  * Returns zero on success; non-zero otherwise
118  */
119 static int ecryptfs_init_lower_file(struct dentry *dentry,
120                                     struct file **lower_file)
121 {
122         const struct cred *cred = current_cred();
123         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
124         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
125         int rc;
126
127         rc = ecryptfs_privileged_open(lower_file, lower_dentry, lower_mnt,
128                                       cred);
129         if (rc) {
130                 printk(KERN_ERR "Error opening lower file "
131                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
132                        "rc = [%d]\n", lower_dentry, lower_mnt, rc);
133                 (*lower_file) = NULL;
134         }
135         return rc;
136 }
137
138 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
139 {
140         struct ecryptfs_inode_info *inode_info;
141         int count, rc = 0;
142
143         inode_info = ecryptfs_inode_to_private(inode);
144         mutex_lock(&inode_info->lower_file_mutex);
145         count = atomic_inc_return(&inode_info->lower_file_count);
146         if (WARN_ON_ONCE(count < 1))
147                 rc = -EINVAL;
148         else if (count == 1) {
149                 rc = ecryptfs_init_lower_file(dentry,
150                                               &inode_info->lower_file);
151                 if (rc)
152                         atomic_set(&inode_info->lower_file_count, 0);
153         }
154         mutex_unlock(&inode_info->lower_file_mutex);
155         return rc;
156 }
157
158 void ecryptfs_put_lower_file(struct inode *inode)
159 {
160         struct ecryptfs_inode_info *inode_info;
161
162         inode_info = ecryptfs_inode_to_private(inode);
163         if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
164                                       &inode_info->lower_file_mutex)) {
165                 fput(inode_info->lower_file);
166                 inode_info->lower_file = NULL;
167                 mutex_unlock(&inode_info->lower_file_mutex);
168         }
169 }
170
171 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
172        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
173        ecryptfs_opt_ecryptfs_key_bytes,
174        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
175        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
176        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
177        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
178        ecryptfs_opt_check_dev_ruid,
179        ecryptfs_opt_err };
180
181 static const match_table_t tokens = {
182         {ecryptfs_opt_sig, "sig=%s"},
183         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
184         {ecryptfs_opt_cipher, "cipher=%s"},
185         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
186         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
187         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
188         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
189         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
190         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
191         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
192         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
193         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
194         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
195         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
196         {ecryptfs_opt_err, NULL}
197 };
198
199 static int ecryptfs_init_global_auth_toks(
200         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
201 {
202         struct ecryptfs_global_auth_tok *global_auth_tok;
203         struct ecryptfs_auth_tok *auth_tok;
204         int rc = 0;
205
206         list_for_each_entry(global_auth_tok,
207                             &mount_crypt_stat->global_auth_tok_list,
208                             mount_crypt_stat_list) {
209                 rc = ecryptfs_keyring_auth_tok_for_sig(
210                         &global_auth_tok->global_auth_tok_key, &auth_tok,
211                         global_auth_tok->sig);
212                 if (rc) {
213                         printk(KERN_ERR "Could not find valid key in user "
214                                "session keyring for sig specified in mount "
215                                "option: [%s]\n", global_auth_tok->sig);
216                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
217                         goto out;
218                 } else {
219                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
220                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
221                 }
222         }
223 out:
224         return rc;
225 }
226
227 static void ecryptfs_init_mount_crypt_stat(
228         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
229 {
230         memset((void *)mount_crypt_stat, 0,
231                sizeof(struct ecryptfs_mount_crypt_stat));
232         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
233         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
234         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
235 }
236
237 /**
238  * ecryptfs_parse_options
239  * @sb: The ecryptfs super block
240  * @options: The options passed to the kernel
241  * @check_ruid: set to 1 if device uid should be checked against the ruid
242  *
243  * Parse mount options:
244  * debug=N         - ecryptfs_verbosity level for debug output
245  * sig=XXX         - description(signature) of the key to use
246  *
247  * Returns the dentry object of the lower-level (lower/interposed)
248  * directory; We want to mount our stackable file system on top of
249  * that lower directory.
250  *
251  * The signature of the key to use must be the description of a key
252  * already in the keyring. Mounting will fail if the key can not be
253  * found.
254  *
255  * Returns zero on success; non-zero on error
256  */
257 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
258                                   uid_t *check_ruid)
259 {
260         char *p;
261         int rc = 0;
262         int sig_set = 0;
263         int cipher_name_set = 0;
264         int fn_cipher_name_set = 0;
265         int cipher_key_bytes;
266         int cipher_key_bytes_set = 0;
267         int fn_cipher_key_bytes;
268         int fn_cipher_key_bytes_set = 0;
269         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
270                 &sbi->mount_crypt_stat;
271         substring_t args[MAX_OPT_ARGS];
272         int token;
273         char *sig_src;
274         char *cipher_name_dst;
275         char *cipher_name_src;
276         char *fn_cipher_name_dst;
277         char *fn_cipher_name_src;
278         char *fnek_dst;
279         char *fnek_src;
280         char *cipher_key_bytes_src;
281         char *fn_cipher_key_bytes_src;
282
283         *check_ruid = 0;
284
285         if (!options) {
286                 rc = -EINVAL;
287                 goto out;
288         }
289         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
290         while ((p = strsep(&options, ",")) != NULL) {
291                 if (!*p)
292                         continue;
293                 token = match_token(p, tokens, args);
294                 switch (token) {
295                 case ecryptfs_opt_sig:
296                 case ecryptfs_opt_ecryptfs_sig:
297                         sig_src = args[0].from;
298                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
299                                                           sig_src, 0);
300                         if (rc) {
301                                 printk(KERN_ERR "Error attempting to register "
302                                        "global sig; rc = [%d]\n", rc);
303                                 goto out;
304                         }
305                         sig_set = 1;
306                         break;
307                 case ecryptfs_opt_cipher:
308                 case ecryptfs_opt_ecryptfs_cipher:
309                         cipher_name_src = args[0].from;
310                         cipher_name_dst =
311                                 mount_crypt_stat->
312                                 global_default_cipher_name;
313                         strncpy(cipher_name_dst, cipher_name_src,
314                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
315                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
316                         cipher_name_set = 1;
317                         break;
318                 case ecryptfs_opt_ecryptfs_key_bytes:
319                         cipher_key_bytes_src = args[0].from;
320                         cipher_key_bytes =
321                                 (int)simple_strtol(cipher_key_bytes_src,
322                                                    &cipher_key_bytes_src, 0);
323                         mount_crypt_stat->global_default_cipher_key_size =
324                                 cipher_key_bytes;
325                         cipher_key_bytes_set = 1;
326                         break;
327                 case ecryptfs_opt_passthrough:
328                         mount_crypt_stat->flags |=
329                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
330                         break;
331                 case ecryptfs_opt_xattr_metadata:
332                         mount_crypt_stat->flags |=
333                                 ECRYPTFS_XATTR_METADATA_ENABLED;
334                         break;
335                 case ecryptfs_opt_encrypted_view:
336                         mount_crypt_stat->flags |=
337                                 ECRYPTFS_XATTR_METADATA_ENABLED;
338                         mount_crypt_stat->flags |=
339                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
340                         break;
341                 case ecryptfs_opt_fnek_sig:
342                         fnek_src = args[0].from;
343                         fnek_dst =
344                                 mount_crypt_stat->global_default_fnek_sig;
345                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
346                         mount_crypt_stat->global_default_fnek_sig[
347                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
348                         rc = ecryptfs_add_global_auth_tok(
349                                 mount_crypt_stat,
350                                 mount_crypt_stat->global_default_fnek_sig,
351                                 ECRYPTFS_AUTH_TOK_FNEK);
352                         if (rc) {
353                                 printk(KERN_ERR "Error attempting to register "
354                                        "global fnek sig [%s]; rc = [%d]\n",
355                                        mount_crypt_stat->global_default_fnek_sig,
356                                        rc);
357                                 goto out;
358                         }
359                         mount_crypt_stat->flags |=
360                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
361                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
362                         break;
363                 case ecryptfs_opt_fn_cipher:
364                         fn_cipher_name_src = args[0].from;
365                         fn_cipher_name_dst =
366                                 mount_crypt_stat->global_default_fn_cipher_name;
367                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
368                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
369                         mount_crypt_stat->global_default_fn_cipher_name[
370                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
371                         fn_cipher_name_set = 1;
372                         break;
373                 case ecryptfs_opt_fn_cipher_key_bytes:
374                         fn_cipher_key_bytes_src = args[0].from;
375                         fn_cipher_key_bytes =
376                                 (int)simple_strtol(fn_cipher_key_bytes_src,
377                                                    &fn_cipher_key_bytes_src, 0);
378                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
379                                 fn_cipher_key_bytes;
380                         fn_cipher_key_bytes_set = 1;
381                         break;
382                 case ecryptfs_opt_unlink_sigs:
383                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
384                         break;
385                 case ecryptfs_opt_mount_auth_tok_only:
386                         mount_crypt_stat->flags |=
387                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
388                         break;
389                 case ecryptfs_opt_check_dev_ruid:
390                         *check_ruid = 1;
391                         break;
392                 case ecryptfs_opt_err:
393                 default:
394                         printk(KERN_WARNING
395                                "%s: eCryptfs: unrecognized option [%s]\n",
396                                __func__, p);
397                 }
398         }
399         if (!sig_set) {
400                 rc = -EINVAL;
401                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
402                                 "auth tok signature as a mount "
403                                 "parameter; see the eCryptfs README\n");
404                 goto out;
405         }
406         if (!cipher_name_set) {
407                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
408
409                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
410                 strcpy(mount_crypt_stat->global_default_cipher_name,
411                        ECRYPTFS_DEFAULT_CIPHER);
412         }
413         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
414             && !fn_cipher_name_set)
415                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
416                        mount_crypt_stat->global_default_cipher_name);
417         if (!cipher_key_bytes_set)
418                 mount_crypt_stat->global_default_cipher_key_size = 0;
419         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
420             && !fn_cipher_key_bytes_set)
421                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
422                         mount_crypt_stat->global_default_cipher_key_size;
423         mutex_lock(&key_tfm_list_mutex);
424         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
425                                  NULL)) {
426                 rc = ecryptfs_add_new_key_tfm(
427                         NULL, mount_crypt_stat->global_default_cipher_name,
428                         mount_crypt_stat->global_default_cipher_key_size);
429                 if (rc) {
430                         printk(KERN_ERR "Error attempting to initialize "
431                                "cipher with name = [%s] and key size = [%td]; "
432                                "rc = [%d]\n",
433                                mount_crypt_stat->global_default_cipher_name,
434                                mount_crypt_stat->global_default_cipher_key_size,
435                                rc);
436                         rc = -EINVAL;
437                         mutex_unlock(&key_tfm_list_mutex);
438                         goto out;
439                 }
440         }
441         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
442             && !ecryptfs_tfm_exists(
443                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
444                 rc = ecryptfs_add_new_key_tfm(
445                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
446                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
447                 if (rc) {
448                         printk(KERN_ERR "Error attempting to initialize "
449                                "cipher with name = [%s] and key size = [%td]; "
450                                "rc = [%d]\n",
451                                mount_crypt_stat->global_default_fn_cipher_name,
452                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
453                                rc);
454                         rc = -EINVAL;
455                         mutex_unlock(&key_tfm_list_mutex);
456                         goto out;
457                 }
458         }
459         mutex_unlock(&key_tfm_list_mutex);
460         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
461         if (rc)
462                 printk(KERN_WARNING "One or more global auth toks could not "
463                        "properly register; rc = [%d]\n", rc);
464 out:
465         return rc;
466 }
467
468 struct kmem_cache *ecryptfs_sb_info_cache;
469 static struct file_system_type ecryptfs_fs_type;
470
471 /**
472  * ecryptfs_get_sb
473  * @fs_type
474  * @flags
475  * @dev_name: The path to mount over
476  * @raw_data: The options passed into the kernel
477  */
478 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
479                         const char *dev_name, void *raw_data)
480 {
481         struct super_block *s;
482         struct ecryptfs_sb_info *sbi;
483         struct ecryptfs_dentry_info *root_info;
484         const char *err = "Getting sb failed";
485         struct inode *inode;
486         struct path path;
487         uid_t check_ruid;
488         int rc;
489
490         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
491         if (!sbi) {
492                 rc = -ENOMEM;
493                 goto out;
494         }
495
496         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
497         if (rc) {
498                 err = "Error parsing options";
499                 goto out;
500         }
501
502         s = sget(fs_type, NULL, set_anon_super, NULL);
503         if (IS_ERR(s)) {
504                 rc = PTR_ERR(s);
505                 goto out;
506         }
507
508         s->s_flags = flags;
509         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
510         if (rc)
511                 goto out1;
512
513         ecryptfs_set_superblock_private(s, sbi);
514         s->s_bdi = &sbi->bdi;
515
516         /* ->kill_sb() will take care of sbi after that point */
517         sbi = NULL;
518         s->s_op = &ecryptfs_sops;
519         s->s_d_op = &ecryptfs_dops;
520
521         err = "Reading sb failed";
522         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
523         if (rc) {
524                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
525                 goto out1;
526         }
527         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
528                 rc = -EINVAL;
529                 printk(KERN_ERR "Mount on filesystem of type "
530                         "eCryptfs explicitly disallowed due to "
531                         "known incompatibilities\n");
532                 goto out_free;
533         }
534
535         if (check_ruid && path.dentry->d_inode->i_uid != current_uid()) {
536                 rc = -EPERM;
537                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
538                        "requested user (uid: %d)\n",
539                        path.dentry->d_inode->i_uid, current_uid());
540                 goto out_free;
541         }
542
543         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
544         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
545         s->s_blocksize = path.dentry->d_sb->s_blocksize;
546         s->s_magic = ECRYPTFS_SUPER_MAGIC;
547
548         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
549         rc = PTR_ERR(inode);
550         if (IS_ERR(inode))
551                 goto out_free;
552
553         s->s_root = d_make_root(inode);
554         if (!s->s_root) {
555                 rc = -ENOMEM;
556                 goto out_free;
557         }
558
559         rc = -ENOMEM;
560         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
561         if (!root_info)
562                 goto out_free;
563
564         /* ->kill_sb() will take care of root_info */
565         ecryptfs_set_dentry_private(s->s_root, root_info);
566         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
567         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
568
569         s->s_flags |= MS_ACTIVE;
570         return dget(s->s_root);
571
572 out_free:
573         path_put(&path);
574 out1:
575         deactivate_locked_super(s);
576 out:
577         if (sbi) {
578                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
579                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
580         }
581         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
582         return ERR_PTR(rc);
583 }
584
585 /**
586  * ecryptfs_kill_block_super
587  * @sb: The ecryptfs super block
588  *
589  * Used to bring the superblock down and free the private data.
590  */
591 static void ecryptfs_kill_block_super(struct super_block *sb)
592 {
593         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
594         kill_anon_super(sb);
595         if (!sb_info)
596                 return;
597         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
598         bdi_destroy(&sb_info->bdi);
599         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
600 }
601
602 static struct file_system_type ecryptfs_fs_type = {
603         .owner = THIS_MODULE,
604         .name = "ecryptfs",
605         .mount = ecryptfs_mount,
606         .kill_sb = ecryptfs_kill_block_super,
607         .fs_flags = 0
608 };
609
610 /**
611  * inode_info_init_once
612  *
613  * Initializes the ecryptfs_inode_info_cache when it is created
614  */
615 static void
616 inode_info_init_once(void *vptr)
617 {
618         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
619
620         inode_init_once(&ei->vfs_inode);
621 }
622
623 static struct ecryptfs_cache_info {
624         struct kmem_cache **cache;
625         const char *name;
626         size_t size;
627         void (*ctor)(void *obj);
628 } ecryptfs_cache_infos[] = {
629         {
630                 .cache = &ecryptfs_auth_tok_list_item_cache,
631                 .name = "ecryptfs_auth_tok_list_item",
632                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
633         },
634         {
635                 .cache = &ecryptfs_file_info_cache,
636                 .name = "ecryptfs_file_cache",
637                 .size = sizeof(struct ecryptfs_file_info),
638         },
639         {
640                 .cache = &ecryptfs_dentry_info_cache,
641                 .name = "ecryptfs_dentry_info_cache",
642                 .size = sizeof(struct ecryptfs_dentry_info),
643         },
644         {
645                 .cache = &ecryptfs_inode_info_cache,
646                 .name = "ecryptfs_inode_cache",
647                 .size = sizeof(struct ecryptfs_inode_info),
648                 .ctor = inode_info_init_once,
649         },
650         {
651                 .cache = &ecryptfs_sb_info_cache,
652                 .name = "ecryptfs_sb_cache",
653                 .size = sizeof(struct ecryptfs_sb_info),
654         },
655         {
656                 .cache = &ecryptfs_header_cache,
657                 .name = "ecryptfs_headers",
658                 .size = PAGE_CACHE_SIZE,
659         },
660         {
661                 .cache = &ecryptfs_xattr_cache,
662                 .name = "ecryptfs_xattr_cache",
663                 .size = PAGE_CACHE_SIZE,
664         },
665         {
666                 .cache = &ecryptfs_key_record_cache,
667                 .name = "ecryptfs_key_record_cache",
668                 .size = sizeof(struct ecryptfs_key_record),
669         },
670         {
671                 .cache = &ecryptfs_key_sig_cache,
672                 .name = "ecryptfs_key_sig_cache",
673                 .size = sizeof(struct ecryptfs_key_sig),
674         },
675         {
676                 .cache = &ecryptfs_global_auth_tok_cache,
677                 .name = "ecryptfs_global_auth_tok_cache",
678                 .size = sizeof(struct ecryptfs_global_auth_tok),
679         },
680         {
681                 .cache = &ecryptfs_key_tfm_cache,
682                 .name = "ecryptfs_key_tfm_cache",
683                 .size = sizeof(struct ecryptfs_key_tfm),
684         },
685         {
686                 .cache = &ecryptfs_open_req_cache,
687                 .name = "ecryptfs_open_req_cache",
688                 .size = sizeof(struct ecryptfs_open_req),
689         },
690 };
691
692 static void ecryptfs_free_kmem_caches(void)
693 {
694         int i;
695
696         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
697                 struct ecryptfs_cache_info *info;
698
699                 info = &ecryptfs_cache_infos[i];
700                 if (*(info->cache))
701                         kmem_cache_destroy(*(info->cache));
702         }
703 }
704
705 /**
706  * ecryptfs_init_kmem_caches
707  *
708  * Returns zero on success; non-zero otherwise
709  */
710 static int ecryptfs_init_kmem_caches(void)
711 {
712         int i;
713
714         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
715                 struct ecryptfs_cache_info *info;
716
717                 info = &ecryptfs_cache_infos[i];
718                 *(info->cache) = kmem_cache_create(info->name, info->size,
719                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
720                 if (!*(info->cache)) {
721                         ecryptfs_free_kmem_caches();
722                         ecryptfs_printk(KERN_WARNING, "%s: "
723                                         "kmem_cache_create failed\n",
724                                         info->name);
725                         return -ENOMEM;
726                 }
727         }
728         return 0;
729 }
730
731 static struct kobject *ecryptfs_kobj;
732
733 static ssize_t version_show(struct kobject *kobj,
734                             struct kobj_attribute *attr, char *buff)
735 {
736         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
737 }
738
739 static struct kobj_attribute version_attr = __ATTR_RO(version);
740
741 static struct attribute *attributes[] = {
742         &version_attr.attr,
743         NULL,
744 };
745
746 static struct attribute_group attr_group = {
747         .attrs = attributes,
748 };
749
750 static int do_sysfs_registration(void)
751 {
752         int rc;
753
754         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
755         if (!ecryptfs_kobj) {
756                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
757                 rc = -ENOMEM;
758                 goto out;
759         }
760         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
761         if (rc) {
762                 printk(KERN_ERR
763                        "Unable to create ecryptfs version attributes\n");
764                 kobject_put(ecryptfs_kobj);
765         }
766 out:
767         return rc;
768 }
769
770 static void do_sysfs_unregistration(void)
771 {
772         sysfs_remove_group(ecryptfs_kobj, &attr_group);
773         kobject_put(ecryptfs_kobj);
774 }
775
776 static int __init ecryptfs_init(void)
777 {
778         int rc;
779
780         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
781                 rc = -EINVAL;
782                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
783                                 "larger than the host's page size, and so "
784                                 "eCryptfs cannot run on this system. The "
785                                 "default eCryptfs extent size is [%u] bytes; "
786                                 "the page size is [%lu] bytes.\n",
787                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
788                                 (unsigned long)PAGE_CACHE_SIZE);
789                 goto out;
790         }
791         rc = ecryptfs_init_kmem_caches();
792         if (rc) {
793                 printk(KERN_ERR
794                        "Failed to allocate one or more kmem_cache objects\n");
795                 goto out;
796         }
797         rc = register_filesystem(&ecryptfs_fs_type);
798         if (rc) {
799                 printk(KERN_ERR "Failed to register filesystem\n");
800                 goto out_free_kmem_caches;
801         }
802         rc = do_sysfs_registration();
803         if (rc) {
804                 printk(KERN_ERR "sysfs registration failed\n");
805                 goto out_unregister_filesystem;
806         }
807         rc = ecryptfs_init_kthread();
808         if (rc) {
809                 printk(KERN_ERR "%s: kthread initialization failed; "
810                        "rc = [%d]\n", __func__, rc);
811                 goto out_do_sysfs_unregistration;
812         }
813         rc = ecryptfs_init_messaging();
814         if (rc) {
815                 printk(KERN_ERR "Failure occurred while attempting to "
816                                 "initialize the communications channel to "
817                                 "ecryptfsd\n");
818                 goto out_destroy_kthread;
819         }
820         rc = ecryptfs_init_crypto();
821         if (rc) {
822                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
823                        "rc = [%d]\n", rc);
824                 goto out_release_messaging;
825         }
826         if (ecryptfs_verbosity > 0)
827                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
828                         "will be written to the syslog!\n", ecryptfs_verbosity);
829
830         goto out;
831 out_release_messaging:
832         ecryptfs_release_messaging();
833 out_destroy_kthread:
834         ecryptfs_destroy_kthread();
835 out_do_sysfs_unregistration:
836         do_sysfs_unregistration();
837 out_unregister_filesystem:
838         unregister_filesystem(&ecryptfs_fs_type);
839 out_free_kmem_caches:
840         ecryptfs_free_kmem_caches();
841 out:
842         return rc;
843 }
844
845 static void __exit ecryptfs_exit(void)
846 {
847         int rc;
848
849         rc = ecryptfs_destroy_crypto();
850         if (rc)
851                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
852                        "rc = [%d]\n", rc);
853         ecryptfs_release_messaging();
854         ecryptfs_destroy_kthread();
855         do_sysfs_unregistration();
856         unregister_filesystem(&ecryptfs_fs_type);
857         ecryptfs_free_kmem_caches();
858 }
859
860 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
861 MODULE_DESCRIPTION("eCryptfs");
862
863 MODULE_LICENSE("GPL");
864
865 module_init(ecryptfs_init)
866 module_exit(ecryptfs_exit)