1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * eCryptfs: Linux filesystem encryption layer
4 *
5 * Copyright (C) 1997-2003 Erez Zadok
6 * Copyright (C) 2001-2003 Stony Brook University
7 * Copyright (C) 2004-2007 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
10 * Tyler Hicks <code@tyhicks.com>
11 */
12
13#include <linux/dcache.h>
14#include <linux/file.h>
15#include <linux/module.h>
16#include <linux/namei.h>
17#include <linux/skbuff.h>
18#include <linux/mount.h>
19#include <linux/pagemap.h>
20#include <linux/key.h>
21#include <linux/parser.h>
22#include <linux/fs_stack.h>
23#include <linux/slab.h>
24#include <linux/magic.h>
25#include "ecryptfs_kernel.h"
26
27/*
28 * Module parameter that defines the ecryptfs_verbosity level.
29 */
30int ecryptfs_verbosity = 0;
31
32module_param(ecryptfs_verbosity, int, 0);
33MODULE_PARM_DESC(ecryptfs_verbosity,
34 "Initial verbosity level (0 or 1; defaults to "
35 "0, which is Quiet)");
36
37/*
38 * Module parameter that defines the number of message buffer elements
39 */
40unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
41
42module_param(ecryptfs_message_buf_len, uint, 0);
43MODULE_PARM_DESC(ecryptfs_message_buf_len,
44 "Number of message buffer elements");
45
46/*
47 * Module parameter that defines the maximum guaranteed amount of time to wait
48 * for a response from ecryptfsd. The actual sleep time will be, more than
49 * likely, a small amount greater than this specified value, but only less if
50 * the message successfully arrives.
51 */
52signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
53
54module_param(ecryptfs_message_wait_timeout, long, 0);
55MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
56 "Maximum number of seconds that an operation will "
57 "sleep while waiting for a message response from "
58 "userspace");
59
60/*
61 * Module parameter that is an estimate of the maximum number of users
62 * that will be concurrently using eCryptfs. Set this to the right
63 * value to balance performance and memory use.
64 */
65unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
66
67module_param(ecryptfs_number_of_users, uint, 0);
68MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
69 "concurrent users of eCryptfs");
70
71void __ecryptfs_printk(const char *fmt, ...)
72{
73 va_list args;
74 va_start(args, fmt);
75 if (fmt[1] == '7') { /* KERN_DEBUG */
76 if (ecryptfs_verbosity >= 1)
77 vprintk(fmt, args);
78 } else
79 vprintk(fmt, args);
80 va_end(args);
81}
82
83/*
84 * ecryptfs_init_lower_file
85 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
86 * the lower dentry and the lower mount set
87 *
88 * eCryptfs only ever keeps a single open file for every lower
89 * inode. All I/O operations to the lower inode occur through that
90 * file. When the first eCryptfs dentry that interposes with the first
91 * lower dentry for that inode is created, this function creates the
92 * lower file struct and associates it with the eCryptfs
93 * inode. When all eCryptfs files associated with the inode are released, the
94 * file is closed.
95 *
96 * The lower file will be opened with read/write permissions, if
97 * possible. Otherwise, it is opened read-only.
98 *
99 * This function does nothing if a lower file is already
100 * associated with the eCryptfs inode.
101 *
102 * Returns zero on success; non-zero otherwise
103 */
104static int ecryptfs_init_lower_file(struct dentry *dentry,
105 struct file **lower_file)
106{
107 const struct cred *cred = current_cred();
108 const struct path *path = ecryptfs_dentry_to_lower_path(dentry);
109 int rc;
110
111 rc = ecryptfs_privileged_open(lower_file, lower_dentry: path->dentry, lower_mnt: path->mnt,
112 cred);
113 if (rc) {
114 printk(KERN_ERR "Error opening lower file "
115 "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
116 "rc = [%d]\n", path->dentry, path->mnt, rc);
117 (*lower_file) = NULL;
118 }
119 return rc;
120}
121
122int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
123{
124 struct ecryptfs_inode_info *inode_info;
125 int count, rc = 0;
126
127 inode_info = ecryptfs_inode_to_private(inode);
128 mutex_lock(&inode_info->lower_file_mutex);
129 count = atomic_inc_return(v: &inode_info->lower_file_count);
130 if (WARN_ON_ONCE(count < 1))
131 rc = -EINVAL;
132 else if (count == 1) {
133 rc = ecryptfs_init_lower_file(dentry,
134 lower_file: &inode_info->lower_file);
135 if (rc)
136 atomic_set(v: &inode_info->lower_file_count, i: 0);
137 }
138 mutex_unlock(lock: &inode_info->lower_file_mutex);
139 return rc;
140}
141
142void ecryptfs_put_lower_file(struct inode *inode)
143{
144 struct ecryptfs_inode_info *inode_info;
145
146 inode_info = ecryptfs_inode_to_private(inode);
147 if (atomic_dec_and_mutex_lock(cnt: &inode_info->lower_file_count,
148 lock: &inode_info->lower_file_mutex)) {
149 filemap_write_and_wait(mapping: inode->i_mapping);
150 fput(inode_info->lower_file);
151 inode_info->lower_file = NULL;
152 mutex_unlock(lock: &inode_info->lower_file_mutex);
153 }
154}
155
156enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
157 ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
158 ecryptfs_opt_ecryptfs_key_bytes,
159 ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
160 ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
161 ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
162 ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
163 ecryptfs_opt_check_dev_ruid,
164 ecryptfs_opt_err };
165
166static const match_table_t tokens = {
167 {ecryptfs_opt_sig, "sig=%s"},
168 {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
169 {ecryptfs_opt_cipher, "cipher=%s"},
170 {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
171 {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
172 {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
173 {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
174 {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
175 {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
176 {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
177 {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
178 {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
179 {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
180 {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
181 {ecryptfs_opt_err, NULL}
182};
183
184static int ecryptfs_init_global_auth_toks(
185 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
186{
187 struct ecryptfs_global_auth_tok *global_auth_tok;
188 struct ecryptfs_auth_tok *auth_tok;
189 int rc = 0;
190
191 list_for_each_entry(global_auth_tok,
192 &mount_crypt_stat->global_auth_tok_list,
193 mount_crypt_stat_list) {
194 rc = ecryptfs_keyring_auth_tok_for_sig(
195 auth_tok_key: &global_auth_tok->global_auth_tok_key, auth_tok: &auth_tok,
196 sig: global_auth_tok->sig);
197 if (rc) {
198 printk(KERN_ERR "Could not find valid key in user "
199 "session keyring for sig specified in mount "
200 "option: [%s]\n", global_auth_tok->sig);
201 global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
202 goto out;
203 } else {
204 global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
205 up_write(sem: &(global_auth_tok->global_auth_tok_key)->sem);
206 }
207 }
208out:
209 return rc;
210}
211
212static void ecryptfs_init_mount_crypt_stat(
213 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
214{
215 memset((void *)mount_crypt_stat, 0,
216 sizeof(struct ecryptfs_mount_crypt_stat));
217 INIT_LIST_HEAD(list: &mount_crypt_stat->global_auth_tok_list);
218 mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
219 mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
220}
221
222/**
223 * ecryptfs_parse_options
224 * @sbi: The ecryptfs super block
225 * @options: The options passed to the kernel
226 * @check_ruid: set to 1 if device uid should be checked against the ruid
227 *
228 * Parse mount options:
229 * debug=N - ecryptfs_verbosity level for debug output
230 * sig=XXX - description(signature) of the key to use
231 *
232 * Returns the dentry object of the lower-level (lower/interposed)
233 * directory; We want to mount our stackable file system on top of
234 * that lower directory.
235 *
236 * The signature of the key to use must be the description of a key
237 * already in the keyring. Mounting will fail if the key can not be
238 * found.
239 *
240 * Returns zero on success; non-zero on error
241 */
242static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
243 uid_t *check_ruid)
244{
245 char *p;
246 int rc = 0;
247 int sig_set = 0;
248 int cipher_name_set = 0;
249 int fn_cipher_name_set = 0;
250 int cipher_key_bytes;
251 int cipher_key_bytes_set = 0;
252 int fn_cipher_key_bytes;
253 int fn_cipher_key_bytes_set = 0;
254 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
255 &sbi->mount_crypt_stat;
256 substring_t args[MAX_OPT_ARGS];
257 int token;
258 char *sig_src;
259 char *cipher_name_dst;
260 char *cipher_name_src;
261 char *fn_cipher_name_dst;
262 char *fn_cipher_name_src;
263 char *fnek_dst;
264 char *fnek_src;
265 char *cipher_key_bytes_src;
266 char *fn_cipher_key_bytes_src;
267 u8 cipher_code;
268
269 *check_ruid = 0;
270
271 if (!options) {
272 rc = -EINVAL;
273 goto out;
274 }
275 ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
276 while ((p = strsep(&options, ",")) != NULL) {
277 if (!*p)
278 continue;
279 token = match_token(p, table: tokens, args);
280 switch (token) {
281 case ecryptfs_opt_sig:
282 case ecryptfs_opt_ecryptfs_sig:
283 sig_src = args[0].from;
284 rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
285 sig: sig_src, global_auth_tok_flags: 0);
286 if (rc) {
287 printk(KERN_ERR "Error attempting to register "
288 "global sig; rc = [%d]\n", rc);
289 goto out;
290 }
291 sig_set = 1;
292 break;
293 case ecryptfs_opt_cipher:
294 case ecryptfs_opt_ecryptfs_cipher:
295 cipher_name_src = args[0].from;
296 cipher_name_dst =
297 mount_crypt_stat->
298 global_default_cipher_name;
299 strncpy(p: cipher_name_dst, q: cipher_name_src,
300 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
301 cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
302 cipher_name_set = 1;
303 break;
304 case ecryptfs_opt_ecryptfs_key_bytes:
305 cipher_key_bytes_src = args[0].from;
306 cipher_key_bytes =
307 (int)simple_strtol(cipher_key_bytes_src,
308 &cipher_key_bytes_src, 0);
309 mount_crypt_stat->global_default_cipher_key_size =
310 cipher_key_bytes;
311 cipher_key_bytes_set = 1;
312 break;
313 case ecryptfs_opt_passthrough:
314 mount_crypt_stat->flags |=
315 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
316 break;
317 case ecryptfs_opt_xattr_metadata:
318 mount_crypt_stat->flags |=
319 ECRYPTFS_XATTR_METADATA_ENABLED;
320 break;
321 case ecryptfs_opt_encrypted_view:
322 mount_crypt_stat->flags |=
323 ECRYPTFS_XATTR_METADATA_ENABLED;
324 mount_crypt_stat->flags |=
325 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
326 break;
327 case ecryptfs_opt_fnek_sig:
328 fnek_src = args[0].from;
329 fnek_dst =
330 mount_crypt_stat->global_default_fnek_sig;
331 strncpy(p: fnek_dst, q: fnek_src, ECRYPTFS_SIG_SIZE_HEX);
332 mount_crypt_stat->global_default_fnek_sig[
333 ECRYPTFS_SIG_SIZE_HEX] = '\0';
334 rc = ecryptfs_add_global_auth_tok(
335 mount_crypt_stat,
336 sig: mount_crypt_stat->global_default_fnek_sig,
337 ECRYPTFS_AUTH_TOK_FNEK);
338 if (rc) {
339 printk(KERN_ERR "Error attempting to register "
340 "global fnek sig [%s]; rc = [%d]\n",
341 mount_crypt_stat->global_default_fnek_sig,
342 rc);
343 goto out;
344 }
345 mount_crypt_stat->flags |=
346 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
347 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
348 break;
349 case ecryptfs_opt_fn_cipher:
350 fn_cipher_name_src = args[0].from;
351 fn_cipher_name_dst =
352 mount_crypt_stat->global_default_fn_cipher_name;
353 strncpy(p: fn_cipher_name_dst, q: fn_cipher_name_src,
354 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
355 mount_crypt_stat->global_default_fn_cipher_name[
356 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
357 fn_cipher_name_set = 1;
358 break;
359 case ecryptfs_opt_fn_cipher_key_bytes:
360 fn_cipher_key_bytes_src = args[0].from;
361 fn_cipher_key_bytes =
362 (int)simple_strtol(fn_cipher_key_bytes_src,
363 &fn_cipher_key_bytes_src, 0);
364 mount_crypt_stat->global_default_fn_cipher_key_bytes =
365 fn_cipher_key_bytes;
366 fn_cipher_key_bytes_set = 1;
367 break;
368 case ecryptfs_opt_unlink_sigs:
369 mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
370 break;
371 case ecryptfs_opt_mount_auth_tok_only:
372 mount_crypt_stat->flags |=
373 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
374 break;
375 case ecryptfs_opt_check_dev_ruid:
376 *check_ruid = 1;
377 break;
378 case ecryptfs_opt_err:
379 default:
380 printk(KERN_WARNING
381 "%s: eCryptfs: unrecognized option [%s]\n",
382 __func__, p);
383 }
384 }
385 if (!sig_set) {
386 rc = -EINVAL;
387 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
388 "auth tok signature as a mount "
389 "parameter; see the eCryptfs README\n");
390 goto out;
391 }
392 if (!cipher_name_set) {
393 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
394
395 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
396 strcpy(p: mount_crypt_stat->global_default_cipher_name,
397 ECRYPTFS_DEFAULT_CIPHER);
398 }
399 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
400 && !fn_cipher_name_set)
401 strcpy(p: mount_crypt_stat->global_default_fn_cipher_name,
402 q: mount_crypt_stat->global_default_cipher_name);
403 if (!cipher_key_bytes_set)
404 mount_crypt_stat->global_default_cipher_key_size = 0;
405 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
406 && !fn_cipher_key_bytes_set)
407 mount_crypt_stat->global_default_fn_cipher_key_bytes =
408 mount_crypt_stat->global_default_cipher_key_size;
409
410 cipher_code = ecryptfs_code_for_cipher_string(
411 cipher_name: mount_crypt_stat->global_default_cipher_name,
412 key_bytes: mount_crypt_stat->global_default_cipher_key_size);
413 if (!cipher_code) {
414 ecryptfs_printk(KERN_ERR,
415 "eCryptfs doesn't support cipher: %s\n",
416 mount_crypt_stat->global_default_cipher_name);
417 rc = -EINVAL;
418 goto out;
419 }
420
421 mutex_lock(&key_tfm_list_mutex);
422 if (!ecryptfs_tfm_exists(cipher_name: mount_crypt_stat->global_default_cipher_name,
423 NULL)) {
424 rc = ecryptfs_add_new_key_tfm(
425 NULL, cipher_name: mount_crypt_stat->global_default_cipher_name,
426 key_size: mount_crypt_stat->global_default_cipher_key_size);
427 if (rc) {
428 printk(KERN_ERR "Error attempting to initialize "
429 "cipher with name = [%s] and key size = [%td]; "
430 "rc = [%d]\n",
431 mount_crypt_stat->global_default_cipher_name,
432 mount_crypt_stat->global_default_cipher_key_size,
433 rc);
434 rc = -EINVAL;
435 mutex_unlock(lock: &key_tfm_list_mutex);
436 goto out;
437 }
438 }
439 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
440 && !ecryptfs_tfm_exists(
441 cipher_name: mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
442 rc = ecryptfs_add_new_key_tfm(
443 NULL, cipher_name: mount_crypt_stat->global_default_fn_cipher_name,
444 key_size: mount_crypt_stat->global_default_fn_cipher_key_bytes);
445 if (rc) {
446 printk(KERN_ERR "Error attempting to initialize "
447 "cipher with name = [%s] and key size = [%td]; "
448 "rc = [%d]\n",
449 mount_crypt_stat->global_default_fn_cipher_name,
450 mount_crypt_stat->global_default_fn_cipher_key_bytes,
451 rc);
452 rc = -EINVAL;
453 mutex_unlock(lock: &key_tfm_list_mutex);
454 goto out;
455 }
456 }
457 mutex_unlock(lock: &key_tfm_list_mutex);
458 rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
459 if (rc)
460 printk(KERN_WARNING "One or more global auth toks could not "
461 "properly register; rc = [%d]\n", rc);
462out:
463 return rc;
464}
465
466struct kmem_cache *ecryptfs_sb_info_cache;
467static struct file_system_type ecryptfs_fs_type;
468
469/*
470 * ecryptfs_mount
471 * @fs_type: The filesystem type that the superblock should belong to
472 * @flags: The flags associated with the mount
473 * @dev_name: The path to mount over
474 * @raw_data: The options passed into the kernel
475 */
476static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
477 const char *dev_name, void *raw_data)
478{
479 struct super_block *s;
480 struct ecryptfs_sb_info *sbi;
481 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
482 struct ecryptfs_dentry_info *root_info;
483 const char *err = "Getting sb failed";
484 struct inode *inode;
485 struct path path;
486 uid_t check_ruid;
487 int rc;
488
489 sbi = kmem_cache_zalloc(k: ecryptfs_sb_info_cache, GFP_KERNEL);
490 if (!sbi) {
491 rc = -ENOMEM;
492 goto out;
493 }
494
495 if (!dev_name) {
496 rc = -EINVAL;
497 err = "Device name cannot be null";
498 goto out;
499 }
500
501 rc = ecryptfs_parse_options(sbi, options: raw_data, check_ruid: &check_ruid);
502 if (rc) {
503 err = "Error parsing options";
504 goto out;
505 }
506 mount_crypt_stat = &sbi->mount_crypt_stat;
507
508 s = sget(type: fs_type, NULL, set: set_anon_super, flags, NULL);
509 if (IS_ERR(ptr: s)) {
510 rc = PTR_ERR(ptr: s);
511 goto out;
512 }
513
514 rc = super_setup_bdi(sb: s);
515 if (rc)
516 goto out1;
517
518 ecryptfs_set_superblock_private(sb: s, sb_info: sbi);
519
520 /* ->kill_sb() will take care of sbi after that point */
521 sbi = NULL;
522 s->s_op = &ecryptfs_sops;
523 s->s_xattr = ecryptfs_xattr_handlers;
524 s->s_d_op = &ecryptfs_dops;
525
526 err = "Reading sb failed";
527 rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
528 if (rc) {
529 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
530 goto out1;
531 }
532 if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
533 rc = -EINVAL;
534 printk(KERN_ERR "Mount on filesystem of type "
535 "eCryptfs explicitly disallowed due to "
536 "known incompatibilities\n");
537 goto out_free;
538 }
539
540 if (is_idmapped_mnt(mnt: path.mnt)) {
541 rc = -EINVAL;
542 printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
543 goto out_free;
544 }
545
546 if (check_ruid && !uid_eq(left: d_inode(dentry: path.dentry)->i_uid, current_uid())) {
547 rc = -EPERM;
548 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
549 "requested user (uid: %d)\n",
550 i_uid_read(d_inode(path.dentry)),
551 from_kuid(&init_user_ns, current_uid()));
552 goto out_free;
553 }
554
555 ecryptfs_set_superblock_lower(sb: s, lower_sb: path.dentry->d_sb);
556
557 /**
558 * Set the POSIX ACL flag based on whether they're enabled in the lower
559 * mount.
560 */
561 s->s_flags = flags & ~SB_POSIXACL;
562 s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
563
564 /**
565 * Force a read-only eCryptfs mount when:
566 * 1) The lower mount is ro
567 * 2) The ecryptfs_encrypted_view mount option is specified
568 */
569 if (sb_rdonly(sb: path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
570 s->s_flags |= SB_RDONLY;
571
572 s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
573 s->s_blocksize = path.dentry->d_sb->s_blocksize;
574 s->s_magic = ECRYPTFS_SUPER_MAGIC;
575 s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
576
577 rc = -EINVAL;
578 if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
579 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
580 goto out_free;
581 }
582
583 inode = ecryptfs_get_inode(lower_inode: d_inode(dentry: path.dentry), sb: s);
584 rc = PTR_ERR(ptr: inode);
585 if (IS_ERR(ptr: inode))
586 goto out_free;
587
588 s->s_root = d_make_root(inode);
589 if (!s->s_root) {
590 rc = -ENOMEM;
591 goto out_free;
592 }
593
594 rc = -ENOMEM;
595 root_info = kmem_cache_zalloc(k: ecryptfs_dentry_info_cache, GFP_KERNEL);
596 if (!root_info)
597 goto out_free;
598
599 /* ->kill_sb() will take care of root_info */
600 ecryptfs_set_dentry_private(dentry: s->s_root, dentry_info: root_info);
601 root_info->lower_path = path;
602
603 s->s_flags |= SB_ACTIVE;
604 return dget(dentry: s->s_root);
605
606out_free:
607 path_put(&path);
608out1:
609 deactivate_locked_super(sb: s);
610out:
611 if (sbi) {
612 ecryptfs_destroy_mount_crypt_stat(mount_crypt_stat: &sbi->mount_crypt_stat);
613 kmem_cache_free(s: ecryptfs_sb_info_cache, objp: sbi);
614 }
615 printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
616 return ERR_PTR(error: rc);
617}
618
619/**
620 * ecryptfs_kill_block_super
621 * @sb: The ecryptfs super block
622 *
623 * Used to bring the superblock down and free the private data.
624 */
625static void ecryptfs_kill_block_super(struct super_block *sb)
626{
627 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
628 kill_anon_super(sb);
629 if (!sb_info)
630 return;
631 ecryptfs_destroy_mount_crypt_stat(mount_crypt_stat: &sb_info->mount_crypt_stat);
632 kmem_cache_free(s: ecryptfs_sb_info_cache, objp: sb_info);
633}
634
635static struct file_system_type ecryptfs_fs_type = {
636 .owner = THIS_MODULE,
637 .name = "ecryptfs",
638 .mount = ecryptfs_mount,
639 .kill_sb = ecryptfs_kill_block_super,
640 .fs_flags = 0
641};
642MODULE_ALIAS_FS("ecryptfs");
643
644/*
645 * inode_info_init_once
646 *
647 * Initializes the ecryptfs_inode_info_cache when it is created
648 */
649static void
650inode_info_init_once(void *vptr)
651{
652 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
653
654 inode_init_once(&ei->vfs_inode);
655}
656
657static struct ecryptfs_cache_info {
658 struct kmem_cache **cache;
659 const char *name;
660 size_t size;
661 slab_flags_t flags;
662 void (*ctor)(void *obj);
663} ecryptfs_cache_infos[] = {
664 {
665 .cache = &ecryptfs_auth_tok_list_item_cache,
666 .name = "ecryptfs_auth_tok_list_item",
667 .size = sizeof(struct ecryptfs_auth_tok_list_item),
668 },
669 {
670 .cache = &ecryptfs_file_info_cache,
671 .name = "ecryptfs_file_cache",
672 .size = sizeof(struct ecryptfs_file_info),
673 },
674 {
675 .cache = &ecryptfs_dentry_info_cache,
676 .name = "ecryptfs_dentry_info_cache",
677 .size = sizeof(struct ecryptfs_dentry_info),
678 },
679 {
680 .cache = &ecryptfs_inode_info_cache,
681 .name = "ecryptfs_inode_cache",
682 .size = sizeof(struct ecryptfs_inode_info),
683 .flags = SLAB_ACCOUNT,
684 .ctor = inode_info_init_once,
685 },
686 {
687 .cache = &ecryptfs_sb_info_cache,
688 .name = "ecryptfs_sb_cache",
689 .size = sizeof(struct ecryptfs_sb_info),
690 },
691 {
692 .cache = &ecryptfs_header_cache,
693 .name = "ecryptfs_headers",
694 .size = PAGE_SIZE,
695 },
696 {
697 .cache = &ecryptfs_xattr_cache,
698 .name = "ecryptfs_xattr_cache",
699 .size = PAGE_SIZE,
700 },
701 {
702 .cache = &ecryptfs_key_record_cache,
703 .name = "ecryptfs_key_record_cache",
704 .size = sizeof(struct ecryptfs_key_record),
705 },
706 {
707 .cache = &ecryptfs_key_sig_cache,
708 .name = "ecryptfs_key_sig_cache",
709 .size = sizeof(struct ecryptfs_key_sig),
710 },
711 {
712 .cache = &ecryptfs_global_auth_tok_cache,
713 .name = "ecryptfs_global_auth_tok_cache",
714 .size = sizeof(struct ecryptfs_global_auth_tok),
715 },
716 {
717 .cache = &ecryptfs_key_tfm_cache,
718 .name = "ecryptfs_key_tfm_cache",
719 .size = sizeof(struct ecryptfs_key_tfm),
720 },
721};
722
723static void ecryptfs_free_kmem_caches(void)
724{
725 int i;
726
727 /*
728 * Make sure all delayed rcu free inodes are flushed before we
729 * destroy cache.
730 */
731 rcu_barrier();
732
733 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
734 struct ecryptfs_cache_info *info;
735
736 info = &ecryptfs_cache_infos[i];
737 kmem_cache_destroy(s: *(info->cache));
738 }
739}
740
741/**
742 * ecryptfs_init_kmem_caches
743 *
744 * Returns zero on success; non-zero otherwise
745 */
746static int ecryptfs_init_kmem_caches(void)
747{
748 int i;
749
750 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
751 struct ecryptfs_cache_info *info;
752
753 info = &ecryptfs_cache_infos[i];
754 *(info->cache) = kmem_cache_create(name: info->name, size: info->size, align: 0,
755 SLAB_HWCACHE_ALIGN | info->flags, ctor: info->ctor);
756 if (!*(info->cache)) {
757 ecryptfs_free_kmem_caches();
758 ecryptfs_printk(KERN_WARNING, "%s: "
759 "kmem_cache_create failed\n",
760 info->name);
761 return -ENOMEM;
762 }
763 }
764 return 0;
765}
766
767static struct kobject *ecryptfs_kobj;
768
769static ssize_t version_show(struct kobject *kobj,
770 struct kobj_attribute *attr, char *buff)
771{
772 return snprintf(buf: buff, PAGE_SIZE, fmt: "%d\n", ECRYPTFS_VERSIONING_MASK);
773}
774
775static struct kobj_attribute version_attr = __ATTR_RO(version);
776
777static struct attribute *attributes[] = {
778 &version_attr.attr,
779 NULL,
780};
781
782static const struct attribute_group attr_group = {
783 .attrs = attributes,
784};
785
786static int do_sysfs_registration(void)
787{
788 int rc;
789
790 ecryptfs_kobj = kobject_create_and_add(name: "ecryptfs", parent: fs_kobj);
791 if (!ecryptfs_kobj) {
792 printk(KERN_ERR "Unable to create ecryptfs kset\n");
793 rc = -ENOMEM;
794 goto out;
795 }
796 rc = sysfs_create_group(kobj: ecryptfs_kobj, grp: &attr_group);
797 if (rc) {
798 printk(KERN_ERR
799 "Unable to create ecryptfs version attributes\n");
800 kobject_put(kobj: ecryptfs_kobj);
801 }
802out:
803 return rc;
804}
805
806static void do_sysfs_unregistration(void)
807{
808 sysfs_remove_group(kobj: ecryptfs_kobj, grp: &attr_group);
809 kobject_put(kobj: ecryptfs_kobj);
810}
811
812static int __init ecryptfs_init(void)
813{
814 int rc;
815
816 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
817 rc = -EINVAL;
818 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
819 "larger than the host's page size, and so "
820 "eCryptfs cannot run on this system. The "
821 "default eCryptfs extent size is [%u] bytes; "
822 "the page size is [%lu] bytes.\n",
823 ECRYPTFS_DEFAULT_EXTENT_SIZE,
824 (unsigned long)PAGE_SIZE);
825 goto out;
826 }
827 rc = ecryptfs_init_kmem_caches();
828 if (rc) {
829 printk(KERN_ERR
830 "Failed to allocate one or more kmem_cache objects\n");
831 goto out;
832 }
833 rc = do_sysfs_registration();
834 if (rc) {
835 printk(KERN_ERR "sysfs registration failed\n");
836 goto out_free_kmem_caches;
837 }
838 rc = ecryptfs_init_kthread();
839 if (rc) {
840 printk(KERN_ERR "%s: kthread initialization failed; "
841 "rc = [%d]\n", __func__, rc);
842 goto out_do_sysfs_unregistration;
843 }
844 rc = ecryptfs_init_messaging();
845 if (rc) {
846 printk(KERN_ERR "Failure occurred while attempting to "
847 "initialize the communications channel to "
848 "ecryptfsd\n");
849 goto out_destroy_kthread;
850 }
851 rc = ecryptfs_init_crypto();
852 if (rc) {
853 printk(KERN_ERR "Failure whilst attempting to init crypto; "
854 "rc = [%d]\n", rc);
855 goto out_release_messaging;
856 }
857 rc = register_filesystem(&ecryptfs_fs_type);
858 if (rc) {
859 printk(KERN_ERR "Failed to register filesystem\n");
860 goto out_destroy_crypto;
861 }
862 if (ecryptfs_verbosity > 0)
863 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
864 "will be written to the syslog!\n", ecryptfs_verbosity);
865
866 goto out;
867out_destroy_crypto:
868 ecryptfs_destroy_crypto();
869out_release_messaging:
870 ecryptfs_release_messaging();
871out_destroy_kthread:
872 ecryptfs_destroy_kthread();
873out_do_sysfs_unregistration:
874 do_sysfs_unregistration();
875out_free_kmem_caches:
876 ecryptfs_free_kmem_caches();
877out:
878 return rc;
879}
880
881static void __exit ecryptfs_exit(void)
882{
883 int rc;
884
885 rc = ecryptfs_destroy_crypto();
886 if (rc)
887 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
888 "rc = [%d]\n", rc);
889 ecryptfs_release_messaging();
890 ecryptfs_destroy_kthread();
891 do_sysfs_unregistration();
892 unregister_filesystem(&ecryptfs_fs_type);
893 ecryptfs_free_kmem_caches();
894}
895
896MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
897MODULE_DESCRIPTION("eCryptfs");
898
899MODULE_LICENSE("GPL");
900
901module_init(ecryptfs_init)
902module_exit(ecryptfs_exit)
903

source code of linux/fs/ecryptfs/main.c