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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 struct path *path = ecryptfs_dentry_to_lower_path(dentry);
109 int rc;
110
111 rc = ecryptfs_privileged_open(lower_file, path->dentry, 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(&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 &inode_info->lower_file);
135 if (rc)
136 atomic_set(&inode_info->lower_file_count, 0);
137 }
138 mutex_unlock(&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(&inode_info->lower_file_count,
148 &inode_info->lower_file_mutex)) {
149 filemap_write_and_wait(inode->i_mapping);
150 fput(inode_info->lower_file);
151 inode_info->lower_file = NULL;
152 mutex_unlock(&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 &global_auth_tok->global_auth_tok_key, &auth_tok,
196 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(&(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(&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 * @sb: 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, 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_src, 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(cipher_name_dst, 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(fnek_dst, 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 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(fn_cipher_name_dst, 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(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(mount_crypt_stat->global_default_fn_cipher_name,
402 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 mount_crypt_stat->global_default_cipher_name,
412 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(mount_crypt_stat->global_default_cipher_name,
423 NULL)) {
424 rc = ecryptfs_add_new_key_tfm(
425 NULL, mount_crypt_stat->global_default_cipher_name,
426 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(&key_tfm_list_mutex);
436 goto out;
437 }
438 }
439 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
440 && !ecryptfs_tfm_exists(
441 mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
442 rc = ecryptfs_add_new_key_tfm(
443 NULL, mount_crypt_stat->global_default_fn_cipher_name,
444 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(&key_tfm_list_mutex);
454 goto out;
455 }
456 }
457 mutex_unlock(&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_get_sb
471 * @fs_type
472 * @flags
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(ecryptfs_sb_info_cache, GFP_KERNEL);
490 if (!sbi) {
491 rc = -ENOMEM;
492 goto out;
493 }
494
495 rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
496 if (rc) {
497 err = "Error parsing options";
498 goto out;
499 }
500 mount_crypt_stat = &sbi->mount_crypt_stat;
501
502 s = sget(fs_type, NULL, set_anon_super, flags, NULL);
503 if (IS_ERR(s)) {
504 rc = PTR_ERR(s);
505 goto out;
506 }
507
508 rc = super_setup_bdi(s);
509 if (rc)
510 goto out1;
511
512 ecryptfs_set_superblock_private(s, sbi);
513
514 /* ->kill_sb() will take care of sbi after that point */
515 sbi = NULL;
516 s->s_op = &ecryptfs_sops;
517 s->s_xattr = ecryptfs_xattr_handlers;
518 s->s_d_op = &ecryptfs_dops;
519
520 err = "Reading sb failed";
521 rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
522 if (rc) {
523 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
524 goto out1;
525 }
526 if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
527 rc = -EINVAL;
528 printk(KERN_ERR "Mount on filesystem of type "
529 "eCryptfs explicitly disallowed due to "
530 "known incompatibilities\n");
531 goto out_free;
532 }
533
534 if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
535 rc = -EPERM;
536 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
537 "requested user (uid: %d)\n",
538 i_uid_read(d_inode(path.dentry)),
539 from_kuid(&init_user_ns, current_uid()));
540 goto out_free;
541 }
542
543 ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
544
545 /**
546 * Set the POSIX ACL flag based on whether they're enabled in the lower
547 * mount.
548 */
549 s->s_flags = flags & ~SB_POSIXACL;
550 s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
551
552 /**
553 * Force a read-only eCryptfs mount when:
554 * 1) The lower mount is ro
555 * 2) The ecryptfs_encrypted_view mount option is specified
556 */
557 if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
558 s->s_flags |= SB_RDONLY;
559
560 s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
561 s->s_blocksize = path.dentry->d_sb->s_blocksize;
562 s->s_magic = ECRYPTFS_SUPER_MAGIC;
563 s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
564
565 rc = -EINVAL;
566 if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
567 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
568 goto out_free;
569 }
570
571 inode = ecryptfs_get_inode(d_inode(path.dentry), s);
572 rc = PTR_ERR(inode);
573 if (IS_ERR(inode))
574 goto out_free;
575
576 s->s_root = d_make_root(inode);
577 if (!s->s_root) {
578 rc = -ENOMEM;
579 goto out_free;
580 }
581
582 rc = -ENOMEM;
583 root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
584 if (!root_info)
585 goto out_free;
586
587 /* ->kill_sb() will take care of root_info */
588 ecryptfs_set_dentry_private(s->s_root, root_info);
589 root_info->lower_path = path;
590
591 s->s_flags |= SB_ACTIVE;
592 return dget(s->s_root);
593
594out_free:
595 path_put(&path);
596out1:
597 deactivate_locked_super(s);
598out:
599 if (sbi) {
600 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
601 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
602 }
603 printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
604 return ERR_PTR(rc);
605}
606
607/**
608 * ecryptfs_kill_block_super
609 * @sb: The ecryptfs super block
610 *
611 * Used to bring the superblock down and free the private data.
612 */
613static void ecryptfs_kill_block_super(struct super_block *sb)
614{
615 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
616 kill_anon_super(sb);
617 if (!sb_info)
618 return;
619 ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
620 kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
621}
622
623static struct file_system_type ecryptfs_fs_type = {
624 .owner = THIS_MODULE,
625 .name = "ecryptfs",
626 .mount = ecryptfs_mount,
627 .kill_sb = ecryptfs_kill_block_super,
628 .fs_flags = 0
629};
630MODULE_ALIAS_FS("ecryptfs");
631
632/**
633 * inode_info_init_once
634 *
635 * Initializes the ecryptfs_inode_info_cache when it is created
636 */
637static void
638inode_info_init_once(void *vptr)
639{
640 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
641
642 inode_init_once(&ei->vfs_inode);
643}
644
645static struct ecryptfs_cache_info {
646 struct kmem_cache **cache;
647 const char *name;
648 size_t size;
649 slab_flags_t flags;
650 void (*ctor)(void *obj);
651} ecryptfs_cache_infos[] = {
652 {
653 .cache = &ecryptfs_auth_tok_list_item_cache,
654 .name = "ecryptfs_auth_tok_list_item",
655 .size = sizeof(struct ecryptfs_auth_tok_list_item),
656 },
657 {
658 .cache = &ecryptfs_file_info_cache,
659 .name = "ecryptfs_file_cache",
660 .size = sizeof(struct ecryptfs_file_info),
661 },
662 {
663 .cache = &ecryptfs_dentry_info_cache,
664 .name = "ecryptfs_dentry_info_cache",
665 .size = sizeof(struct ecryptfs_dentry_info),
666 },
667 {
668 .cache = &ecryptfs_inode_info_cache,
669 .name = "ecryptfs_inode_cache",
670 .size = sizeof(struct ecryptfs_inode_info),
671 .flags = SLAB_ACCOUNT,
672 .ctor = inode_info_init_once,
673 },
674 {
675 .cache = &ecryptfs_sb_info_cache,
676 .name = "ecryptfs_sb_cache",
677 .size = sizeof(struct ecryptfs_sb_info),
678 },
679 {
680 .cache = &ecryptfs_header_cache,
681 .name = "ecryptfs_headers",
682 .size = PAGE_SIZE,
683 },
684 {
685 .cache = &ecryptfs_xattr_cache,
686 .name = "ecryptfs_xattr_cache",
687 .size = PAGE_SIZE,
688 },
689 {
690 .cache = &ecryptfs_key_record_cache,
691 .name = "ecryptfs_key_record_cache",
692 .size = sizeof(struct ecryptfs_key_record),
693 },
694 {
695 .cache = &ecryptfs_key_sig_cache,
696 .name = "ecryptfs_key_sig_cache",
697 .size = sizeof(struct ecryptfs_key_sig),
698 },
699 {
700 .cache = &ecryptfs_global_auth_tok_cache,
701 .name = "ecryptfs_global_auth_tok_cache",
702 .size = sizeof(struct ecryptfs_global_auth_tok),
703 },
704 {
705 .cache = &ecryptfs_key_tfm_cache,
706 .name = "ecryptfs_key_tfm_cache",
707 .size = sizeof(struct ecryptfs_key_tfm),
708 },
709};
710
711static void ecryptfs_free_kmem_caches(void)
712{
713 int i;
714
715 /*
716 * Make sure all delayed rcu free inodes are flushed before we
717 * destroy cache.
718 */
719 rcu_barrier();
720
721 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
722 struct ecryptfs_cache_info *info;
723
724 info = &ecryptfs_cache_infos[i];
725 kmem_cache_destroy(*(info->cache));
726 }
727}
728
729/**
730 * ecryptfs_init_kmem_caches
731 *
732 * Returns zero on success; non-zero otherwise
733 */
734static int ecryptfs_init_kmem_caches(void)
735{
736 int i;
737
738 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
739 struct ecryptfs_cache_info *info;
740
741 info = &ecryptfs_cache_infos[i];
742 *(info->cache) = kmem_cache_create(info->name, info->size, 0,
743 SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
744 if (!*(info->cache)) {
745 ecryptfs_free_kmem_caches();
746 ecryptfs_printk(KERN_WARNING, "%s: "
747 "kmem_cache_create failed\n",
748 info->name);
749 return -ENOMEM;
750 }
751 }
752 return 0;
753}
754
755static struct kobject *ecryptfs_kobj;
756
757static ssize_t version_show(struct kobject *kobj,
758 struct kobj_attribute *attr, char *buff)
759{
760 return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
761}
762
763static struct kobj_attribute version_attr = __ATTR_RO(version);
764
765static struct attribute *attributes[] = {
766 &version_attr.attr,
767 NULL,
768};
769
770static const struct attribute_group attr_group = {
771 .attrs = attributes,
772};
773
774static int do_sysfs_registration(void)
775{
776 int rc;
777
778 ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
779 if (!ecryptfs_kobj) {
780 printk(KERN_ERR "Unable to create ecryptfs kset\n");
781 rc = -ENOMEM;
782 goto out;
783 }
784 rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
785 if (rc) {
786 printk(KERN_ERR
787 "Unable to create ecryptfs version attributes\n");
788 kobject_put(ecryptfs_kobj);
789 }
790out:
791 return rc;
792}
793
794static void do_sysfs_unregistration(void)
795{
796 sysfs_remove_group(ecryptfs_kobj, &attr_group);
797 kobject_put(ecryptfs_kobj);
798}
799
800static int __init ecryptfs_init(void)
801{
802 int rc;
803
804 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
805 rc = -EINVAL;
806 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
807 "larger than the host's page size, and so "
808 "eCryptfs cannot run on this system. The "
809 "default eCryptfs extent size is [%u] bytes; "
810 "the page size is [%lu] bytes.\n",
811 ECRYPTFS_DEFAULT_EXTENT_SIZE,
812 (unsigned long)PAGE_SIZE);
813 goto out;
814 }
815 rc = ecryptfs_init_kmem_caches();
816 if (rc) {
817 printk(KERN_ERR
818 "Failed to allocate one or more kmem_cache objects\n");
819 goto out;
820 }
821 rc = do_sysfs_registration();
822 if (rc) {
823 printk(KERN_ERR "sysfs registration failed\n");
824 goto out_free_kmem_caches;
825 }
826 rc = ecryptfs_init_kthread();
827 if (rc) {
828 printk(KERN_ERR "%s: kthread initialization failed; "
829 "rc = [%d]\n", __func__, rc);
830 goto out_do_sysfs_unregistration;
831 }
832 rc = ecryptfs_init_messaging();
833 if (rc) {
834 printk(KERN_ERR "Failure occurred while attempting to "
835 "initialize the communications channel to "
836 "ecryptfsd\n");
837 goto out_destroy_kthread;
838 }
839 rc = ecryptfs_init_crypto();
840 if (rc) {
841 printk(KERN_ERR "Failure whilst attempting to init crypto; "
842 "rc = [%d]\n", rc);
843 goto out_release_messaging;
844 }
845 rc = register_filesystem(&ecryptfs_fs_type);
846 if (rc) {
847 printk(KERN_ERR "Failed to register filesystem\n");
848 goto out_destroy_crypto;
849 }
850 if (ecryptfs_verbosity > 0)
851 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
852 "will be written to the syslog!\n", ecryptfs_verbosity);
853
854 goto out;
855out_destroy_crypto:
856 ecryptfs_destroy_crypto();
857out_release_messaging:
858 ecryptfs_release_messaging();
859out_destroy_kthread:
860 ecryptfs_destroy_kthread();
861out_do_sysfs_unregistration:
862 do_sysfs_unregistration();
863out_free_kmem_caches:
864 ecryptfs_free_kmem_caches();
865out:
866 return rc;
867}
868
869static void __exit ecryptfs_exit(void)
870{
871 int rc;
872
873 rc = ecryptfs_destroy_crypto();
874 if (rc)
875 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
876 "rc = [%d]\n", rc);
877 ecryptfs_release_messaging();
878 ecryptfs_destroy_kthread();
879 do_sysfs_unregistration();
880 unregister_filesystem(&ecryptfs_fs_type);
881 ecryptfs_free_kmem_caches();
882}
883
884MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
885MODULE_DESCRIPTION("eCryptfs");
886
887MODULE_LICENSE("GPL");
888
889module_init(ecryptfs_init)
890module_exit(ecryptfs_exit)
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, path->dentry, 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(&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 &inode_info->lower_file);
135 if (rc)
136 atomic_set(&inode_info->lower_file_count, 0);
137 }
138 mutex_unlock(&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(&inode_info->lower_file_count,
148 &inode_info->lower_file_mutex)) {
149 filemap_write_and_wait(inode->i_mapping);
150 fput(inode_info->lower_file);
151 inode_info->lower_file = NULL;
152 mutex_unlock(&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 &global_auth_tok->global_auth_tok_key, &auth_tok,
194 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(&(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(&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, ecryptfs_fs_param_spec, param, &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 param->string, 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 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(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(mount_crypt_stat->global_default_fn_cipher_name,
362 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 mount_crypt_stat->global_default_cipher_name,
372 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(mount_crypt_stat->global_default_cipher_name,
383 NULL)) {
384 rc = ecryptfs_add_new_key_tfm(
385 NULL, mount_crypt_stat->global_default_cipher_name,
386 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(&key_tfm_list_mutex);
396 goto out;
397 }
398 }
399 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
400 && !ecryptfs_tfm_exists(
401 mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
402 rc = ecryptfs_add_new_key_tfm(
403 NULL, mount_crypt_stat->global_default_fn_cipher_name,
404 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(&key_tfm_list_mutex);
414 goto out;
415 }
416 }
417 mutex_unlock(&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_anon_super_fc);
459 if (IS_ERR(s)) {
460 rc = PTR_ERR(s);
461 goto out;
462 }
463
464 rc = super_setup_bdi(s);
465 if (rc)
466 goto out1;
467
468 ecryptfs_set_superblock_private(s, 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(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(d_inode(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(s, 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(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(d_inode(path.dentry), s);
535 rc = PTR_ERR(inode);
536 if (IS_ERR(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(s->s_root, root_info);
552 root_info->lower_path = path;
553
554 s->s_flags |= SB_ACTIVE;
555 fc->root = dget(s->s_root);
556 return 0;
557
558out_free:
559 path_put(&path);
560out1:
561 deactivate_locked_super(s);
562out:
563 if (sbi)
564 ecryptfs_destroy_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(&sb_info->mount_crypt_stat);
583 kmem_cache_free(ecryptfs_sb_info_cache, 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(ctx);
592
593 if (sbi) {
594 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
595 kmem_cache_free(ecryptfs_sb_info_cache, 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(ctx);
617 ctx = NULL;
618 return -ENOMEM;
619 }
620
621 ecryptfs_init_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(*(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(buff, PAGE_SIZE, "%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("ecryptfs", 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(ecryptfs_kobj, &attr_group);
792 if (rc) {
793 printk(KERN_ERR
794 "Unable to create ecryptfs version attributes\n");
795 kobject_put(ecryptfs_kobj);
796 }
797out:
798 return rc;
799}
800
801static void do_sysfs_unregistration(void)
802{
803 sysfs_remove_group(ecryptfs_kobj, &attr_group);
804 kobject_put(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)