25aeaa7328badd90fafe2519f2ea4f65bd69e865
[muen/linux.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/mount.h>
33 #include <linux/pagemap.h>
34 #include <linux/key.h>
35 #include <linux/parser.h>
36 #include <linux/fs_stack.h>
37 #include <linux/slab.h>
38 #include <linux/magic.h>
39 #include "ecryptfs_kernel.h"
40
41 /**
42  * Module parameter that defines the ecryptfs_verbosity level.
43  */
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_lower_file
99  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
100  *                   the lower dentry and the lower mount set
101  *
102  * eCryptfs only ever keeps a single open file for every lower
103  * inode. All I/O operations to the lower inode occur through that
104  * file. When the first eCryptfs dentry that interposes with the first
105  * lower dentry for that inode is created, this function creates the
106  * lower file struct and associates it with the eCryptfs
107  * inode. When all eCryptfs files associated with the inode are released, the
108  * file is closed.
109  *
110  * The lower file will be opened with read/write permissions, if
111  * possible. Otherwise, it is opened read-only.
112  *
113  * This function does nothing if a lower file is already
114  * associated with the eCryptfs inode.
115  *
116  * Returns zero on success; non-zero otherwise
117  */
118 static int ecryptfs_init_lower_file(struct dentry *dentry,
119                                     struct file **lower_file)
120 {
121         const struct cred *cred = current_cred();
122         struct path *path = ecryptfs_dentry_to_lower_path(dentry);
123         int rc;
124
125         rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
126                                       cred);
127         if (rc) {
128                 printk(KERN_ERR "Error opening lower file "
129                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
130                        "rc = [%d]\n", path->dentry, path->mnt, rc);
131                 (*lower_file) = NULL;
132         }
133         return rc;
134 }
135
136 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
137 {
138         struct ecryptfs_inode_info *inode_info;
139         int count, rc = 0;
140
141         inode_info = ecryptfs_inode_to_private(inode);
142         mutex_lock(&inode_info->lower_file_mutex);
143         count = atomic_inc_return(&inode_info->lower_file_count);
144         if (WARN_ON_ONCE(count < 1))
145                 rc = -EINVAL;
146         else if (count == 1) {
147                 rc = ecryptfs_init_lower_file(dentry,
148                                               &inode_info->lower_file);
149                 if (rc)
150                         atomic_set(&inode_info->lower_file_count, 0);
151         }
152         mutex_unlock(&inode_info->lower_file_mutex);
153         return rc;
154 }
155
156 void ecryptfs_put_lower_file(struct inode *inode)
157 {
158         struct ecryptfs_inode_info *inode_info;
159
160         inode_info = ecryptfs_inode_to_private(inode);
161         if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
162                                       &inode_info->lower_file_mutex)) {
163                 filemap_write_and_wait(inode->i_mapping);
164                 fput(inode_info->lower_file);
165                 inode_info->lower_file = NULL;
166                 mutex_unlock(&inode_info->lower_file_mutex);
167         }
168 }
169
170 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
171        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
172        ecryptfs_opt_ecryptfs_key_bytes,
173        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
174        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
175        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
176        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
177        ecryptfs_opt_check_dev_ruid,
178        ecryptfs_opt_err };
179
180 static const match_table_t tokens = {
181         {ecryptfs_opt_sig, "sig=%s"},
182         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
183         {ecryptfs_opt_cipher, "cipher=%s"},
184         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
185         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
186         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
187         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
188         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
189         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
190         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
191         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
192         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
193         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
194         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
195         {ecryptfs_opt_err, NULL}
196 };
197
198 static int ecryptfs_init_global_auth_toks(
199         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
200 {
201         struct ecryptfs_global_auth_tok *global_auth_tok;
202         struct ecryptfs_auth_tok *auth_tok;
203         int rc = 0;
204
205         list_for_each_entry(global_auth_tok,
206                             &mount_crypt_stat->global_auth_tok_list,
207                             mount_crypt_stat_list) {
208                 rc = ecryptfs_keyring_auth_tok_for_sig(
209                         &global_auth_tok->global_auth_tok_key, &auth_tok,
210                         global_auth_tok->sig);
211                 if (rc) {
212                         printk(KERN_ERR "Could not find valid key in user "
213                                "session keyring for sig specified in mount "
214                                "option: [%s]\n", global_auth_tok->sig);
215                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
216                         goto out;
217                 } else {
218                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
219                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
220                 }
221         }
222 out:
223         return rc;
224 }
225
226 static void ecryptfs_init_mount_crypt_stat(
227         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
228 {
229         memset((void *)mount_crypt_stat, 0,
230                sizeof(struct ecryptfs_mount_crypt_stat));
231         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
232         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
233         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
234 }
235
236 /**
237  * ecryptfs_parse_options
238  * @sb: The ecryptfs super block
239  * @options: The options passed to the kernel
240  * @check_ruid: set to 1 if device uid should be checked against the ruid
241  *
242  * Parse mount options:
243  * debug=N         - ecryptfs_verbosity level for debug output
244  * sig=XXX         - description(signature) of the key to use
245  *
246  * Returns the dentry object of the lower-level (lower/interposed)
247  * directory; We want to mount our stackable file system on top of
248  * that lower directory.
249  *
250  * The signature of the key to use must be the description of a key
251  * already in the keyring. Mounting will fail if the key can not be
252  * found.
253  *
254  * Returns zero on success; non-zero on error
255  */
256 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
257                                   uid_t *check_ruid)
258 {
259         char *p;
260         int rc = 0;
261         int sig_set = 0;
262         int cipher_name_set = 0;
263         int fn_cipher_name_set = 0;
264         int cipher_key_bytes;
265         int cipher_key_bytes_set = 0;
266         int fn_cipher_key_bytes;
267         int fn_cipher_key_bytes_set = 0;
268         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
269                 &sbi->mount_crypt_stat;
270         substring_t args[MAX_OPT_ARGS];
271         int token;
272         char *sig_src;
273         char *cipher_name_dst;
274         char *cipher_name_src;
275         char *fn_cipher_name_dst;
276         char *fn_cipher_name_src;
277         char *fnek_dst;
278         char *fnek_src;
279         char *cipher_key_bytes_src;
280         char *fn_cipher_key_bytes_src;
281         u8 cipher_code;
282
283         *check_ruid = 0;
284
285         if (!options) {
286                 rc = -EINVAL;
287                 goto out;
288         }
289         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
290         while ((p = strsep(&options, ",")) != NULL) {
291                 if (!*p)
292                         continue;
293                 token = match_token(p, tokens, args);
294                 switch (token) {
295                 case ecryptfs_opt_sig:
296                 case ecryptfs_opt_ecryptfs_sig:
297                         sig_src = args[0].from;
298                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
299                                                           sig_src, 0);
300                         if (rc) {
301                                 printk(KERN_ERR "Error attempting to register "
302                                        "global sig; rc = [%d]\n", rc);
303                                 goto out;
304                         }
305                         sig_set = 1;
306                         break;
307                 case ecryptfs_opt_cipher:
308                 case ecryptfs_opt_ecryptfs_cipher:
309                         cipher_name_src = args[0].from;
310                         cipher_name_dst =
311                                 mount_crypt_stat->
312                                 global_default_cipher_name;
313                         strncpy(cipher_name_dst, cipher_name_src,
314                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
315                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
316                         cipher_name_set = 1;
317                         break;
318                 case ecryptfs_opt_ecryptfs_key_bytes:
319                         cipher_key_bytes_src = args[0].from;
320                         cipher_key_bytes =
321                                 (int)simple_strtol(cipher_key_bytes_src,
322                                                    &cipher_key_bytes_src, 0);
323                         mount_crypt_stat->global_default_cipher_key_size =
324                                 cipher_key_bytes;
325                         cipher_key_bytes_set = 1;
326                         break;
327                 case ecryptfs_opt_passthrough:
328                         mount_crypt_stat->flags |=
329                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
330                         break;
331                 case ecryptfs_opt_xattr_metadata:
332                         mount_crypt_stat->flags |=
333                                 ECRYPTFS_XATTR_METADATA_ENABLED;
334                         break;
335                 case ecryptfs_opt_encrypted_view:
336                         mount_crypt_stat->flags |=
337                                 ECRYPTFS_XATTR_METADATA_ENABLED;
338                         mount_crypt_stat->flags |=
339                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
340                         break;
341                 case ecryptfs_opt_fnek_sig:
342                         fnek_src = args[0].from;
343                         fnek_dst =
344                                 mount_crypt_stat->global_default_fnek_sig;
345                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
346                         mount_crypt_stat->global_default_fnek_sig[
347                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
348                         rc = ecryptfs_add_global_auth_tok(
349                                 mount_crypt_stat,
350                                 mount_crypt_stat->global_default_fnek_sig,
351                                 ECRYPTFS_AUTH_TOK_FNEK);
352                         if (rc) {
353                                 printk(KERN_ERR "Error attempting to register "
354                                        "global fnek sig [%s]; rc = [%d]\n",
355                                        mount_crypt_stat->global_default_fnek_sig,
356                                        rc);
357                                 goto out;
358                         }
359                         mount_crypt_stat->flags |=
360                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
361                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
362                         break;
363                 case ecryptfs_opt_fn_cipher:
364                         fn_cipher_name_src = args[0].from;
365                         fn_cipher_name_dst =
366                                 mount_crypt_stat->global_default_fn_cipher_name;
367                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
368                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
369                         mount_crypt_stat->global_default_fn_cipher_name[
370                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
371                         fn_cipher_name_set = 1;
372                         break;
373                 case ecryptfs_opt_fn_cipher_key_bytes:
374                         fn_cipher_key_bytes_src = args[0].from;
375                         fn_cipher_key_bytes =
376                                 (int)simple_strtol(fn_cipher_key_bytes_src,
377                                                    &fn_cipher_key_bytes_src, 0);
378                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
379                                 fn_cipher_key_bytes;
380                         fn_cipher_key_bytes_set = 1;
381                         break;
382                 case ecryptfs_opt_unlink_sigs:
383                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
384                         break;
385                 case ecryptfs_opt_mount_auth_tok_only:
386                         mount_crypt_stat->flags |=
387                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
388                         break;
389                 case ecryptfs_opt_check_dev_ruid:
390                         *check_ruid = 1;
391                         break;
392                 case ecryptfs_opt_err:
393                 default:
394                         printk(KERN_WARNING
395                                "%s: eCryptfs: unrecognized option [%s]\n",
396                                __func__, p);
397                 }
398         }
399         if (!sig_set) {
400                 rc = -EINVAL;
401                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
402                                 "auth tok signature as a mount "
403                                 "parameter; see the eCryptfs README\n");
404                 goto out;
405         }
406         if (!cipher_name_set) {
407                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
408
409                 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
410                 strcpy(mount_crypt_stat->global_default_cipher_name,
411                        ECRYPTFS_DEFAULT_CIPHER);
412         }
413         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
414             && !fn_cipher_name_set)
415                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
416                        mount_crypt_stat->global_default_cipher_name);
417         if (!cipher_key_bytes_set)
418                 mount_crypt_stat->global_default_cipher_key_size = 0;
419         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
420             && !fn_cipher_key_bytes_set)
421                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
422                         mount_crypt_stat->global_default_cipher_key_size;
423
424         cipher_code = ecryptfs_code_for_cipher_string(
425                 mount_crypt_stat->global_default_cipher_name,
426                 mount_crypt_stat->global_default_cipher_key_size);
427         if (!cipher_code) {
428                 ecryptfs_printk(KERN_ERR,
429                                 "eCryptfs doesn't support cipher: %s",
430                                 mount_crypt_stat->global_default_cipher_name);
431                 rc = -EINVAL;
432                 goto out;
433         }
434
435         mutex_lock(&key_tfm_list_mutex);
436         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
437                                  NULL)) {
438                 rc = ecryptfs_add_new_key_tfm(
439                         NULL, mount_crypt_stat->global_default_cipher_name,
440                         mount_crypt_stat->global_default_cipher_key_size);
441                 if (rc) {
442                         printk(KERN_ERR "Error attempting to initialize "
443                                "cipher with name = [%s] and key size = [%td]; "
444                                "rc = [%d]\n",
445                                mount_crypt_stat->global_default_cipher_name,
446                                mount_crypt_stat->global_default_cipher_key_size,
447                                rc);
448                         rc = -EINVAL;
449                         mutex_unlock(&key_tfm_list_mutex);
450                         goto out;
451                 }
452         }
453         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
454             && !ecryptfs_tfm_exists(
455                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
456                 rc = ecryptfs_add_new_key_tfm(
457                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
458                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
459                 if (rc) {
460                         printk(KERN_ERR "Error attempting to initialize "
461                                "cipher with name = [%s] and key size = [%td]; "
462                                "rc = [%d]\n",
463                                mount_crypt_stat->global_default_fn_cipher_name,
464                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
465                                rc);
466                         rc = -EINVAL;
467                         mutex_unlock(&key_tfm_list_mutex);
468                         goto out;
469                 }
470         }
471         mutex_unlock(&key_tfm_list_mutex);
472         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
473         if (rc)
474                 printk(KERN_WARNING "One or more global auth toks could not "
475                        "properly register; rc = [%d]\n", rc);
476 out:
477         return rc;
478 }
479
480 struct kmem_cache *ecryptfs_sb_info_cache;
481 static struct file_system_type ecryptfs_fs_type;
482
483 /**
484  * ecryptfs_get_sb
485  * @fs_type
486  * @flags
487  * @dev_name: The path to mount over
488  * @raw_data: The options passed into the kernel
489  */
490 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
491                         const char *dev_name, void *raw_data)
492 {
493         struct super_block *s;
494         struct ecryptfs_sb_info *sbi;
495         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
496         struct ecryptfs_dentry_info *root_info;
497         const char *err = "Getting sb failed";
498         struct inode *inode;
499         struct path path;
500         uid_t check_ruid;
501         int rc;
502
503         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
504         if (!sbi) {
505                 rc = -ENOMEM;
506                 goto out;
507         }
508
509         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
510         if (rc) {
511                 err = "Error parsing options";
512                 goto out;
513         }
514         mount_crypt_stat = &sbi->mount_crypt_stat;
515
516         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
517         if (IS_ERR(s)) {
518                 rc = PTR_ERR(s);
519                 goto out;
520         }
521
522         rc = super_setup_bdi(s);
523         if (rc)
524                 goto out1;
525
526         ecryptfs_set_superblock_private(s, sbi);
527
528         /* ->kill_sb() will take care of sbi after that point */
529         sbi = NULL;
530         s->s_op = &ecryptfs_sops;
531         s->s_xattr = ecryptfs_xattr_handlers;
532         s->s_d_op = &ecryptfs_dops;
533
534         err = "Reading sb failed";
535         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
536         if (rc) {
537                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
538                 goto out1;
539         }
540         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
541                 rc = -EINVAL;
542                 printk(KERN_ERR "Mount on filesystem of type "
543                         "eCryptfs explicitly disallowed due to "
544                         "known incompatibilities\n");
545                 goto out_free;
546         }
547
548         if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
549                 rc = -EPERM;
550                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
551                        "requested user (uid: %d)\n",
552                         i_uid_read(d_inode(path.dentry)),
553                         from_kuid(&init_user_ns, current_uid()));
554                 goto out_free;
555         }
556
557         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
558
559         /**
560          * Set the POSIX ACL flag based on whether they're enabled in the lower
561          * mount.
562          */
563         s->s_flags = flags & ~MS_POSIXACL;
564         s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL;
565
566         /**
567          * Force a read-only eCryptfs mount when:
568          *   1) The lower mount is ro
569          *   2) The ecryptfs_encrypted_view mount option is specified
570          */
571         if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
572                 s->s_flags |= MS_RDONLY;
573
574         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
575         s->s_blocksize = path.dentry->d_sb->s_blocksize;
576         s->s_magic = ECRYPTFS_SUPER_MAGIC;
577         s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
578
579         rc = -EINVAL;
580         if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
581                 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
582                 goto out_free;
583         }
584
585         inode = ecryptfs_get_inode(d_inode(path.dentry), s);
586         rc = PTR_ERR(inode);
587         if (IS_ERR(inode))
588                 goto out_free;
589
590         s->s_root = d_make_root(inode);
591         if (!s->s_root) {
592                 rc = -ENOMEM;
593                 goto out_free;
594         }
595
596         rc = -ENOMEM;
597         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
598         if (!root_info)
599                 goto out_free;
600
601         /* ->kill_sb() will take care of root_info */
602         ecryptfs_set_dentry_private(s->s_root, root_info);
603         root_info->lower_path = path;
604
605         s->s_flags |= MS_ACTIVE;
606         return dget(s->s_root);
607
608 out_free:
609         path_put(&path);
610 out1:
611         deactivate_locked_super(s);
612 out:
613         if (sbi) {
614                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
615                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
616         }
617         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
618         return ERR_PTR(rc);
619 }
620
621 /**
622  * ecryptfs_kill_block_super
623  * @sb: The ecryptfs super block
624  *
625  * Used to bring the superblock down and free the private data.
626  */
627 static void ecryptfs_kill_block_super(struct super_block *sb)
628 {
629         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
630         kill_anon_super(sb);
631         if (!sb_info)
632                 return;
633         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
634         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
635 }
636
637 static struct file_system_type ecryptfs_fs_type = {
638         .owner = THIS_MODULE,
639         .name = "ecryptfs",
640         .mount = ecryptfs_mount,
641         .kill_sb = ecryptfs_kill_block_super,
642         .fs_flags = 0
643 };
644 MODULE_ALIAS_FS("ecryptfs");
645
646 /**
647  * inode_info_init_once
648  *
649  * Initializes the ecryptfs_inode_info_cache when it is created
650  */
651 static void
652 inode_info_init_once(void *vptr)
653 {
654         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
655
656         inode_init_once(&ei->vfs_inode);
657 }
658
659 static struct ecryptfs_cache_info {
660         struct kmem_cache **cache;
661         const char *name;
662         size_t size;
663         slab_flags_t flags;
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                 .flags = SLAB_ACCOUNT,
686                 .ctor = inode_info_init_once,
687         },
688         {
689                 .cache = &ecryptfs_sb_info_cache,
690                 .name = "ecryptfs_sb_cache",
691                 .size = sizeof(struct ecryptfs_sb_info),
692         },
693         {
694                 .cache = &ecryptfs_header_cache,
695                 .name = "ecryptfs_headers",
696                 .size = PAGE_SIZE,
697         },
698         {
699                 .cache = &ecryptfs_xattr_cache,
700                 .name = "ecryptfs_xattr_cache",
701                 .size = PAGE_SIZE,
702         },
703         {
704                 .cache = &ecryptfs_key_record_cache,
705                 .name = "ecryptfs_key_record_cache",
706                 .size = sizeof(struct ecryptfs_key_record),
707         },
708         {
709                 .cache = &ecryptfs_key_sig_cache,
710                 .name = "ecryptfs_key_sig_cache",
711                 .size = sizeof(struct ecryptfs_key_sig),
712         },
713         {
714                 .cache = &ecryptfs_global_auth_tok_cache,
715                 .name = "ecryptfs_global_auth_tok_cache",
716                 .size = sizeof(struct ecryptfs_global_auth_tok),
717         },
718         {
719                 .cache = &ecryptfs_key_tfm_cache,
720                 .name = "ecryptfs_key_tfm_cache",
721                 .size = sizeof(struct ecryptfs_key_tfm),
722         },
723 };
724
725 static void ecryptfs_free_kmem_caches(void)
726 {
727         int i;
728
729         /*
730          * Make sure all delayed rcu free inodes are flushed before we
731          * destroy cache.
732          */
733         rcu_barrier();
734
735         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
736                 struct ecryptfs_cache_info *info;
737
738                 info = &ecryptfs_cache_infos[i];
739                 kmem_cache_destroy(*(info->cache));
740         }
741 }
742
743 /**
744  * ecryptfs_init_kmem_caches
745  *
746  * Returns zero on success; non-zero otherwise
747  */
748 static int ecryptfs_init_kmem_caches(void)
749 {
750         int i;
751
752         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
753                 struct ecryptfs_cache_info *info;
754
755                 info = &ecryptfs_cache_infos[i];
756                 *(info->cache) = kmem_cache_create(info->name, info->size, 0,
757                                 SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
758                 if (!*(info->cache)) {
759                         ecryptfs_free_kmem_caches();
760                         ecryptfs_printk(KERN_WARNING, "%s: "
761                                         "kmem_cache_create failed\n",
762                                         info->name);
763                         return -ENOMEM;
764                 }
765         }
766         return 0;
767 }
768
769 static struct kobject *ecryptfs_kobj;
770
771 static ssize_t version_show(struct kobject *kobj,
772                             struct kobj_attribute *attr, char *buff)
773 {
774         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
775 }
776
777 static struct kobj_attribute version_attr = __ATTR_RO(version);
778
779 static struct attribute *attributes[] = {
780         &version_attr.attr,
781         NULL,
782 };
783
784 static struct attribute_group attr_group = {
785         .attrs = attributes,
786 };
787
788 static int do_sysfs_registration(void)
789 {
790         int rc;
791
792         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
793         if (!ecryptfs_kobj) {
794                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
795                 rc = -ENOMEM;
796                 goto out;
797         }
798         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
799         if (rc) {
800                 printk(KERN_ERR
801                        "Unable to create ecryptfs version attributes\n");
802                 kobject_put(ecryptfs_kobj);
803         }
804 out:
805         return rc;
806 }
807
808 static void do_sysfs_unregistration(void)
809 {
810         sysfs_remove_group(ecryptfs_kobj, &attr_group);
811         kobject_put(ecryptfs_kobj);
812 }
813
814 static int __init ecryptfs_init(void)
815 {
816         int rc;
817
818         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
819                 rc = -EINVAL;
820                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
821                                 "larger than the host's page size, and so "
822                                 "eCryptfs cannot run on this system. The "
823                                 "default eCryptfs extent size is [%u] bytes; "
824                                 "the page size is [%lu] bytes.\n",
825                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
826                                 (unsigned long)PAGE_SIZE);
827                 goto out;
828         }
829         rc = ecryptfs_init_kmem_caches();
830         if (rc) {
831                 printk(KERN_ERR
832                        "Failed to allocate one or more kmem_cache objects\n");
833                 goto out;
834         }
835         rc = do_sysfs_registration();
836         if (rc) {
837                 printk(KERN_ERR "sysfs registration failed\n");
838                 goto out_free_kmem_caches;
839         }
840         rc = ecryptfs_init_kthread();
841         if (rc) {
842                 printk(KERN_ERR "%s: kthread initialization failed; "
843                        "rc = [%d]\n", __func__, rc);
844                 goto out_do_sysfs_unregistration;
845         }
846         rc = ecryptfs_init_messaging();
847         if (rc) {
848                 printk(KERN_ERR "Failure occurred while attempting to "
849                                 "initialize the communications channel to "
850                                 "ecryptfsd\n");
851                 goto out_destroy_kthread;
852         }
853         rc = ecryptfs_init_crypto();
854         if (rc) {
855                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
856                        "rc = [%d]\n", rc);
857                 goto out_release_messaging;
858         }
859         rc = register_filesystem(&ecryptfs_fs_type);
860         if (rc) {
861                 printk(KERN_ERR "Failed to register filesystem\n");
862                 goto out_destroy_crypto;
863         }
864         if (ecryptfs_verbosity > 0)
865                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
866                         "will be written to the syslog!\n", ecryptfs_verbosity);
867
868         goto out;
869 out_destroy_crypto:
870         ecryptfs_destroy_crypto();
871 out_release_messaging:
872         ecryptfs_release_messaging();
873 out_destroy_kthread:
874         ecryptfs_destroy_kthread();
875 out_do_sysfs_unregistration:
876         do_sysfs_unregistration();
877 out_free_kmem_caches:
878         ecryptfs_free_kmem_caches();
879 out:
880         return rc;
881 }
882
883 static void __exit ecryptfs_exit(void)
884 {
885         int rc;
886
887         rc = ecryptfs_destroy_crypto();
888         if (rc)
889                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
890                        "rc = [%d]\n", rc);
891         ecryptfs_release_messaging();
892         ecryptfs_destroy_kthread();
893         do_sysfs_unregistration();
894         unregister_filesystem(&ecryptfs_fs_type);
895         ecryptfs_free_kmem_caches();
896 }
897
898 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
899 MODULE_DESCRIPTION("eCryptfs");
900
901 MODULE_LICENSE("GPL");
902
903 module_init(ecryptfs_init)
904 module_exit(ecryptfs_exit)