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/pagemap.h>
19#include <linux/key.h>
20#include <linux/fs_context.h>
21#include <linux/fs_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 {
157 Opt_sig, Opt_ecryptfs_sig, Opt_cipher, Opt_ecryptfs_cipher,
158 Opt_ecryptfs_key_bytes, Opt_passthrough, Opt_xattr_metadata,
159 Opt_encrypted_view, Opt_fnek_sig, Opt_fn_cipher,
160 Opt_fn_cipher_key_bytes, Opt_unlink_sigs, Opt_mount_auth_tok_only,
161 Opt_check_dev_ruid
162};
163
164static const struct fs_parameter_spec ecryptfs_fs_param_spec[] = {
165 fsparam_string ("sig", Opt_sig),
166 fsparam_string ("ecryptfs_sig", Opt_ecryptfs_sig),
167 fsparam_string ("cipher", Opt_cipher),
168 fsparam_string ("ecryptfs_cipher", Opt_ecryptfs_cipher),
169 fsparam_u32 ("ecryptfs_key_bytes", Opt_ecryptfs_key_bytes),
170 fsparam_flag ("ecryptfs_passthrough", Opt_passthrough),
171 fsparam_flag ("ecryptfs_xattr_metadata", Opt_xattr_metadata),
172 fsparam_flag ("ecryptfs_encrypted_view", Opt_encrypted_view),
173 fsparam_string ("ecryptfs_fnek_sig", Opt_fnek_sig),
174 fsparam_string ("ecryptfs_fn_cipher", Opt_fn_cipher),
175 fsparam_u32 ("ecryptfs_fn_key_bytes", Opt_fn_cipher_key_bytes),
176 fsparam_flag ("ecryptfs_unlink_sigs", Opt_unlink_sigs),
177 fsparam_flag ("ecryptfs_mount_auth_tok_only", Opt_mount_auth_tok_only),
178 fsparam_flag ("ecryptfs_check_dev_ruid", Opt_check_dev_ruid),
179 {}
180};
181
182static int ecryptfs_init_global_auth_toks(
183 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
184{
185 struct ecryptfs_global_auth_tok *global_auth_tok;
186 struct ecryptfs_auth_tok *auth_tok;
187 int rc = 0;
188
189 list_for_each_entry(global_auth_tok,
190 &mount_crypt_stat->global_auth_tok_list,
191 mount_crypt_stat_list) {
192 rc = ecryptfs_keyring_auth_tok_for_sig(
193 auth_tok_key: &global_auth_tok->global_auth_tok_key, auth_tok: &auth_tok,
194 sig: global_auth_tok->sig);
195 if (rc) {
196 printk(KERN_ERR "Could not find valid key in user "
197 "session keyring for sig specified in mount "
198 "option: [%s]\n", global_auth_tok->sig);
199 global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
200 goto out;
201 } else {
202 global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
203 up_write(sem: &(global_auth_tok->global_auth_tok_key)->sem);
204 }
205 }
206out:
207 return rc;
208}
209
210static void ecryptfs_init_mount_crypt_stat(
211 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
212{
213 memset((void *)mount_crypt_stat, 0,
214 sizeof(struct ecryptfs_mount_crypt_stat));
215 INIT_LIST_HEAD(list: &mount_crypt_stat->global_auth_tok_list);
216 mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
217 mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
218}
219
220struct ecryptfs_fs_context {
221 /* Mount option status trackers */
222 bool check_ruid;
223 bool sig_set;
224 bool cipher_name_set;
225 bool cipher_key_bytes_set;
226 bool fn_cipher_name_set;
227 bool fn_cipher_key_bytes_set;
228};
229
230/**
231 * ecryptfs_parse_param
232 * @fc: The ecryptfs filesystem context
233 * @param: The mount parameter to parse
234 *
235 * The signature of the key to use must be the description of a key
236 * already in the keyring. Mounting will fail if the key can not be
237 * found.
238 *
239 * Returns zero on success; non-zero on error
240 */
241static int ecryptfs_parse_param(
242 struct fs_context *fc,
243 struct fs_parameter *param)
244{
245 int rc;
246 int opt;
247 struct fs_parse_result result;
248 struct ecryptfs_fs_context *ctx = fc->fs_private;
249 struct ecryptfs_sb_info *sbi = fc->s_fs_info;
250 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
251 &sbi->mount_crypt_stat;
252
253 opt = fs_parse(fc, desc: ecryptfs_fs_param_spec, param, result: &result);
254 if (opt < 0)
255 return opt;
256
257 switch (opt) {
258 case Opt_sig:
259 case Opt_ecryptfs_sig:
260 rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
261 sig: param->string, global_auth_tok_flags: 0);
262 if (rc) {
263 printk(KERN_ERR "Error attempting to register "
264 "global sig; rc = [%d]\n", rc);
265 return rc;
266 }
267 ctx->sig_set = 1;
268 break;
269 case Opt_cipher:
270 case Opt_ecryptfs_cipher:
271 strscpy(mount_crypt_stat->global_default_cipher_name,
272 param->string);
273 ctx->cipher_name_set = 1;
274 break;
275 case Opt_ecryptfs_key_bytes:
276 mount_crypt_stat->global_default_cipher_key_size =
277 result.uint_32;
278 ctx->cipher_key_bytes_set = 1;
279 break;
280 case Opt_passthrough:
281 mount_crypt_stat->flags |=
282 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
283 break;
284 case Opt_xattr_metadata:
285 mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
286 break;
287 case Opt_encrypted_view:
288 mount_crypt_stat->flags |= ECRYPTFS_XATTR_METADATA_ENABLED;
289 mount_crypt_stat->flags |= ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
290 break;
291 case Opt_fnek_sig:
292 strscpy(mount_crypt_stat->global_default_fnek_sig,
293 param->string);
294 rc = ecryptfs_add_global_auth_tok(
295 mount_crypt_stat,
296 sig: mount_crypt_stat->global_default_fnek_sig,
297 ECRYPTFS_AUTH_TOK_FNEK);
298 if (rc) {
299 printk(KERN_ERR "Error attempting to register "
300 "global fnek sig [%s]; rc = [%d]\n",
301 mount_crypt_stat->global_default_fnek_sig, rc);
302 return rc;
303 }
304 mount_crypt_stat->flags |=
305 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
306 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
307 break;
308 case Opt_fn_cipher:
309 strscpy(mount_crypt_stat->global_default_fn_cipher_name,
310 param->string);
311 ctx->fn_cipher_name_set = 1;
312 break;
313 case Opt_fn_cipher_key_bytes:
314 mount_crypt_stat->global_default_fn_cipher_key_bytes =
315 result.uint_32;
316 ctx->fn_cipher_key_bytes_set = 1;
317 break;
318 case Opt_unlink_sigs:
319 mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
320 break;
321 case Opt_mount_auth_tok_only:
322 mount_crypt_stat->flags |= ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
323 break;
324 case Opt_check_dev_ruid:
325 ctx->check_ruid = 1;
326 break;
327 default:
328 return -EINVAL;
329 }
330
331 return 0;
332}
333
334static int ecryptfs_validate_options(struct fs_context *fc)
335{
336 int rc = 0;
337 u8 cipher_code;
338 struct ecryptfs_fs_context *ctx = fc->fs_private;
339 struct ecryptfs_sb_info *sbi = fc->s_fs_info;
340 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
341
342
343 mount_crypt_stat = &sbi->mount_crypt_stat;
344
345 if (!ctx->sig_set) {
346 rc = -EINVAL;
347 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
348 "auth tok signature as a mount "
349 "parameter; see the eCryptfs README\n");
350 goto out;
351 }
352 if (!ctx->cipher_name_set) {
353 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
354
355 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
356 strcpy(p: mount_crypt_stat->global_default_cipher_name,
357 ECRYPTFS_DEFAULT_CIPHER);
358 }
359 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
360 && !ctx->fn_cipher_name_set)
361 strcpy(p: mount_crypt_stat->global_default_fn_cipher_name,
362 q: mount_crypt_stat->global_default_cipher_name);
363 if (!ctx->cipher_key_bytes_set)
364 mount_crypt_stat->global_default_cipher_key_size = 0;
365 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
366 && !ctx->fn_cipher_key_bytes_set)
367 mount_crypt_stat->global_default_fn_cipher_key_bytes =
368 mount_crypt_stat->global_default_cipher_key_size;
369
370 cipher_code = ecryptfs_code_for_cipher_string(
371 cipher_name: mount_crypt_stat->global_default_cipher_name,
372 key_bytes: mount_crypt_stat->global_default_cipher_key_size);
373 if (!cipher_code) {
374 ecryptfs_printk(KERN_ERR,
375 "eCryptfs doesn't support cipher: %s\n",
376 mount_crypt_stat->global_default_cipher_name);
377 rc = -EINVAL;
378 goto out;
379 }
380
381 mutex_lock(&key_tfm_list_mutex);
382 if (!ecryptfs_tfm_exists(cipher_name: mount_crypt_stat->global_default_cipher_name,
383 NULL)) {
384 rc = ecryptfs_add_new_key_tfm(
385 NULL, cipher_name: mount_crypt_stat->global_default_cipher_name,
386 key_size: mount_crypt_stat->global_default_cipher_key_size);
387 if (rc) {
388 printk(KERN_ERR "Error attempting to initialize "
389 "cipher with name = [%s] and key size = [%td]; "
390 "rc = [%d]\n",
391 mount_crypt_stat->global_default_cipher_name,
392 mount_crypt_stat->global_default_cipher_key_size,
393 rc);
394 rc = -EINVAL;
395 mutex_unlock(lock: &key_tfm_list_mutex);
396 goto out;
397 }
398 }
399 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
400 && !ecryptfs_tfm_exists(
401 cipher_name: mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
402 rc = ecryptfs_add_new_key_tfm(
403 NULL, cipher_name: mount_crypt_stat->global_default_fn_cipher_name,
404 key_size: mount_crypt_stat->global_default_fn_cipher_key_bytes);
405 if (rc) {
406 printk(KERN_ERR "Error attempting to initialize "
407 "cipher with name = [%s] and key size = [%td]; "
408 "rc = [%d]\n",
409 mount_crypt_stat->global_default_fn_cipher_name,
410 mount_crypt_stat->global_default_fn_cipher_key_bytes,
411 rc);
412 rc = -EINVAL;
413 mutex_unlock(lock: &key_tfm_list_mutex);
414 goto out;
415 }
416 }
417 mutex_unlock(lock: &key_tfm_list_mutex);
418 rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
419 if (rc)
420 printk(KERN_WARNING "One or more global auth toks could not "
421 "properly register; rc = [%d]\n", rc);
422out:
423 return rc;
424}
425
426struct kmem_cache *ecryptfs_sb_info_cache;
427static struct file_system_type ecryptfs_fs_type;
428
429/*
430 * ecryptfs_get_tree
431 * @fc: The filesystem context
432 */
433static int ecryptfs_get_tree(struct fs_context *fc)
434{
435 struct super_block *s;
436 struct ecryptfs_fs_context *ctx = fc->fs_private;
437 struct ecryptfs_sb_info *sbi = fc->s_fs_info;
438 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
439 struct ecryptfs_dentry_info *root_info;
440 const char *err = "Getting sb failed";
441 struct inode *inode;
442 struct path path;
443 int rc;
444
445 if (!fc->source) {
446 rc = -EINVAL;
447 err = "Device name cannot be null";
448 goto out;
449 }
450
451 mount_crypt_stat = &sbi->mount_crypt_stat;
452 rc = ecryptfs_validate_options(fc);
453 if (rc) {
454 err = "Error validating options";
455 goto out;
456 }
457
458 s = sget_fc(fc, NULL, set: set_anon_super_fc);
459 if (IS_ERR(ptr: s)) {
460 rc = PTR_ERR(ptr: s);
461 goto out;
462 }
463
464 rc = super_setup_bdi(sb: s);
465 if (rc)
466 goto out1;
467
468 ecryptfs_set_superblock_private(sb: s, sb_info: sbi);
469
470 /* ->kill_sb() will take care of sbi after that point */
471 sbi = NULL;
472 s->s_op = &ecryptfs_sops;
473 s->s_xattr = ecryptfs_xattr_handlers;
474 s->s_d_op = &ecryptfs_dops;
475
476 err = "Reading sb failed";
477 rc = kern_path(fc->source, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
478 if (rc) {
479 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
480 goto out1;
481 }
482 if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
483 rc = -EINVAL;
484 printk(KERN_ERR "Mount on filesystem of type "
485 "eCryptfs explicitly disallowed due to "
486 "known incompatibilities\n");
487 goto out_free;
488 }
489
490 if (is_idmapped_mnt(mnt: path.mnt)) {
491 rc = -EINVAL;
492 printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
493 goto out_free;
494 }
495
496 if (ctx->check_ruid &&
497 !uid_eq(left: d_inode(dentry: path.dentry)->i_uid, current_uid())) {
498 rc = -EPERM;
499 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
500 "requested user (uid: %d)\n",
501 i_uid_read(d_inode(path.dentry)),
502 from_kuid(&init_user_ns, current_uid()));
503 goto out_free;
504 }
505
506 ecryptfs_set_superblock_lower(sb: s, lower_sb: path.dentry->d_sb);
507
508 /**
509 * Set the POSIX ACL flag based on whether they're enabled in the lower
510 * mount.
511 */
512 s->s_flags = fc->sb_flags & ~SB_POSIXACL;
513 s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
514
515 /**
516 * Force a read-only eCryptfs mount when:
517 * 1) The lower mount is ro
518 * 2) The ecryptfs_encrypted_view mount option is specified
519 */
520 if (sb_rdonly(sb: path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
521 s->s_flags |= SB_RDONLY;
522
523 s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
524 s->s_blocksize = path.dentry->d_sb->s_blocksize;
525 s->s_magic = ECRYPTFS_SUPER_MAGIC;
526 s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
527
528 rc = -EINVAL;
529 if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
530 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
531 goto out_free;
532 }
533
534 inode = ecryptfs_get_inode(lower_inode: d_inode(dentry: path.dentry), sb: s);
535 rc = PTR_ERR(ptr: inode);
536 if (IS_ERR(ptr: inode))
537 goto out_free;
538
539 s->s_root = d_make_root(inode);
540 if (!s->s_root) {
541 rc = -ENOMEM;
542 goto out_free;
543 }
544
545 rc = -ENOMEM;
546 root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
547 if (!root_info)
548 goto out_free;
549
550 /* ->kill_sb() will take care of root_info */
551 ecryptfs_set_dentry_private(dentry: s->s_root, dentry_info: root_info);
552 root_info->lower_path = path;
553
554 s->s_flags |= SB_ACTIVE;
555 fc->root = dget(dentry: s->s_root);
556 return 0;
557
558out_free:
559 path_put(&path);
560out1:
561 deactivate_locked_super(sb: s);
562out:
563 if (sbi)
564 ecryptfs_destroy_mount_crypt_stat(mount_crypt_stat: &sbi->mount_crypt_stat);
565
566 printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
567 return rc;
568}
569
570/**
571 * ecryptfs_kill_block_super
572 * @sb: The ecryptfs super block
573 *
574 * Used to bring the superblock down and free the private data.
575 */
576static void ecryptfs_kill_block_super(struct super_block *sb)
577{
578 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
579 kill_anon_super(sb);
580 if (!sb_info)
581 return;
582 ecryptfs_destroy_mount_crypt_stat(mount_crypt_stat: &sb_info->mount_crypt_stat);
583 kmem_cache_free(s: ecryptfs_sb_info_cache, objp: sb_info);
584}
585
586static void ecryptfs_free_fc(struct fs_context *fc)
587{
588 struct ecryptfs_fs_context *ctx = fc->fs_private;
589 struct ecryptfs_sb_info *sbi = fc->s_fs_info;
590
591 kfree(objp: ctx);
592
593 if (sbi) {
594 ecryptfs_destroy_mount_crypt_stat(mount_crypt_stat: &sbi->mount_crypt_stat);
595 kmem_cache_free(s: ecryptfs_sb_info_cache, objp: sbi);
596 }
597}
598
599static const struct fs_context_operations ecryptfs_context_ops = {
600 .free = ecryptfs_free_fc,
601 .parse_param = ecryptfs_parse_param,
602 .get_tree = ecryptfs_get_tree,
603 .reconfigure = NULL,
604};
605
606static int ecryptfs_init_fs_context(struct fs_context *fc)
607{
608 struct ecryptfs_fs_context *ctx;
609 struct ecryptfs_sb_info *sbi = NULL;
610
611 ctx = kzalloc(sizeof(struct ecryptfs_fs_context), GFP_KERNEL);
612 if (!ctx)
613 return -ENOMEM;
614 sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
615 if (!sbi) {
616 kfree(objp: ctx);
617 ctx = NULL;
618 return -ENOMEM;
619 }
620
621 ecryptfs_init_mount_crypt_stat(mount_crypt_stat: &sbi->mount_crypt_stat);
622
623 fc->fs_private = ctx;
624 fc->s_fs_info = sbi;
625 fc->ops = &ecryptfs_context_ops;
626 return 0;
627}
628
629static struct file_system_type ecryptfs_fs_type = {
630 .owner = THIS_MODULE,
631 .name = "ecryptfs",
632 .init_fs_context = ecryptfs_init_fs_context,
633 .parameters = ecryptfs_fs_param_spec,
634 .kill_sb = ecryptfs_kill_block_super,
635 .fs_flags = 0
636};
637MODULE_ALIAS_FS("ecryptfs");
638
639/*
640 * inode_info_init_once
641 *
642 * Initializes the ecryptfs_inode_info_cache when it is created
643 */
644static void
645inode_info_init_once(void *vptr)
646{
647 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
648
649 inode_init_once(&ei->vfs_inode);
650}
651
652static struct ecryptfs_cache_info {
653 struct kmem_cache **cache;
654 const char *name;
655 size_t size;
656 slab_flags_t flags;
657 void (*ctor)(void *obj);
658} ecryptfs_cache_infos[] = {
659 {
660 .cache = &ecryptfs_auth_tok_list_item_cache,
661 .name = "ecryptfs_auth_tok_list_item",
662 .size = sizeof(struct ecryptfs_auth_tok_list_item),
663 },
664 {
665 .cache = &ecryptfs_file_info_cache,
666 .name = "ecryptfs_file_cache",
667 .size = sizeof(struct ecryptfs_file_info),
668 },
669 {
670 .cache = &ecryptfs_dentry_info_cache,
671 .name = "ecryptfs_dentry_info_cache",
672 .size = sizeof(struct ecryptfs_dentry_info),
673 },
674 {
675 .cache = &ecryptfs_inode_info_cache,
676 .name = "ecryptfs_inode_cache",
677 .size = sizeof(struct ecryptfs_inode_info),
678 .flags = SLAB_ACCOUNT,
679 .ctor = inode_info_init_once,
680 },
681 {
682 .cache = &ecryptfs_sb_info_cache,
683 .name = "ecryptfs_sb_cache",
684 .size = sizeof(struct ecryptfs_sb_info),
685 },
686 {
687 .cache = &ecryptfs_header_cache,
688 .name = "ecryptfs_headers",
689 .size = PAGE_SIZE,
690 },
691 {
692 .cache = &ecryptfs_xattr_cache,
693 .name = "ecryptfs_xattr_cache",
694 .size = PAGE_SIZE,
695 },
696 {
697 .cache = &ecryptfs_key_record_cache,
698 .name = "ecryptfs_key_record_cache",
699 .size = sizeof(struct ecryptfs_key_record),
700 },
701 {
702 .cache = &ecryptfs_key_sig_cache,
703 .name = "ecryptfs_key_sig_cache",
704 .size = sizeof(struct ecryptfs_key_sig),
705 },
706 {
707 .cache = &ecryptfs_global_auth_tok_cache,
708 .name = "ecryptfs_global_auth_tok_cache",
709 .size = sizeof(struct ecryptfs_global_auth_tok),
710 },
711 {
712 .cache = &ecryptfs_key_tfm_cache,
713 .name = "ecryptfs_key_tfm_cache",
714 .size = sizeof(struct ecryptfs_key_tfm),
715 },
716};
717
718static void ecryptfs_free_kmem_caches(void)
719{
720 int i;
721
722 /*
723 * Make sure all delayed rcu free inodes are flushed before we
724 * destroy cache.
725 */
726 rcu_barrier();
727
728 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
729 struct ecryptfs_cache_info *info;
730
731 info = &ecryptfs_cache_infos[i];
732 kmem_cache_destroy(s: *(info->cache));
733 }
734}
735
736/**
737 * ecryptfs_init_kmem_caches
738 *
739 * Returns zero on success; non-zero otherwise
740 */
741static int ecryptfs_init_kmem_caches(void)
742{
743 int i;
744
745 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
746 struct ecryptfs_cache_info *info;
747
748 info = &ecryptfs_cache_infos[i];
749 *(info->cache) = kmem_cache_create(info->name, info->size, 0,
750 SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
751 if (!*(info->cache)) {
752 ecryptfs_free_kmem_caches();
753 ecryptfs_printk(KERN_WARNING, "%s: "
754 "kmem_cache_create failed\n",
755 info->name);
756 return -ENOMEM;
757 }
758 }
759 return 0;
760}
761
762static struct kobject *ecryptfs_kobj;
763
764static ssize_t version_show(struct kobject *kobj,
765 struct kobj_attribute *attr, char *buff)
766{
767 return snprintf(buf: buff, PAGE_SIZE, fmt: "%d\n", ECRYPTFS_VERSIONING_MASK);
768}
769
770static struct kobj_attribute version_attr = __ATTR_RO(version);
771
772static struct attribute *attributes[] = {
773 &version_attr.attr,
774 NULL,
775};
776
777static const struct attribute_group attr_group = {
778 .attrs = attributes,
779};
780
781static int do_sysfs_registration(void)
782{
783 int rc;
784
785 ecryptfs_kobj = kobject_create_and_add(name: "ecryptfs", parent: fs_kobj);
786 if (!ecryptfs_kobj) {
787 printk(KERN_ERR "Unable to create ecryptfs kset\n");
788 rc = -ENOMEM;
789 goto out;
790 }
791 rc = sysfs_create_group(kobj: ecryptfs_kobj, grp: &attr_group);
792 if (rc) {
793 printk(KERN_ERR
794 "Unable to create ecryptfs version attributes\n");
795 kobject_put(kobj: ecryptfs_kobj);
796 }
797out:
798 return rc;
799}
800
801static void do_sysfs_unregistration(void)
802{
803 sysfs_remove_group(kobj: ecryptfs_kobj, grp: &attr_group);
804 kobject_put(kobj: ecryptfs_kobj);
805}
806
807static int __init ecryptfs_init(void)
808{
809 int rc;
810
811 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
812 rc = -EINVAL;
813 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
814 "larger than the host's page size, and so "
815 "eCryptfs cannot run on this system. The "
816 "default eCryptfs extent size is [%u] bytes; "
817 "the page size is [%lu] bytes.\n",
818 ECRYPTFS_DEFAULT_EXTENT_SIZE,
819 (unsigned long)PAGE_SIZE);
820 goto out;
821 }
822 rc = ecryptfs_init_kmem_caches();
823 if (rc) {
824 printk(KERN_ERR
825 "Failed to allocate one or more kmem_cache objects\n");
826 goto out;
827 }
828 rc = do_sysfs_registration();
829 if (rc) {
830 printk(KERN_ERR "sysfs registration failed\n");
831 goto out_free_kmem_caches;
832 }
833 rc = ecryptfs_init_kthread();
834 if (rc) {
835 printk(KERN_ERR "%s: kthread initialization failed; "
836 "rc = [%d]\n", __func__, rc);
837 goto out_do_sysfs_unregistration;
838 }
839 rc = ecryptfs_init_messaging();
840 if (rc) {
841 printk(KERN_ERR "Failure occurred while attempting to "
842 "initialize the communications channel to "
843 "ecryptfsd\n");
844 goto out_destroy_kthread;
845 }
846 rc = ecryptfs_init_crypto();
847 if (rc) {
848 printk(KERN_ERR "Failure whilst attempting to init crypto; "
849 "rc = [%d]\n", rc);
850 goto out_release_messaging;
851 }
852 rc = register_filesystem(&ecryptfs_fs_type);
853 if (rc) {
854 printk(KERN_ERR "Failed to register filesystem\n");
855 goto out_destroy_crypto;
856 }
857 if (ecryptfs_verbosity > 0)
858 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
859 "will be written to the syslog!\n", ecryptfs_verbosity);
860
861 goto out;
862out_destroy_crypto:
863 ecryptfs_destroy_crypto();
864out_release_messaging:
865 ecryptfs_release_messaging();
866out_destroy_kthread:
867 ecryptfs_destroy_kthread();
868out_do_sysfs_unregistration:
869 do_sysfs_unregistration();
870out_free_kmem_caches:
871 ecryptfs_free_kmem_caches();
872out:
873 return rc;
874}
875
876static void __exit ecryptfs_exit(void)
877{
878 int rc;
879
880 rc = ecryptfs_destroy_crypto();
881 if (rc)
882 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
883 "rc = [%d]\n", rc);
884 ecryptfs_release_messaging();
885 ecryptfs_destroy_kthread();
886 do_sysfs_unregistration();
887 unregister_filesystem(&ecryptfs_fs_type);
888 ecryptfs_free_kmem_caches();
889}
890
891MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
892MODULE_DESCRIPTION("eCryptfs");
893
894MODULE_LICENSE("GPL");
895
896module_init(ecryptfs_init)
897module_exit(ecryptfs_exit)
898

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