1 /** 2 * eCryptfs: Linux filesystem encryption layer 3 * 4 * Copyright (C) 1997-2003 Erez Zadok 5 * Copyright (C) 2001-2003 Stony Brook University 6 * Copyright (C) 2004-2007 International Business Machines Corp. 7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> 8 * Michael C. Thompson <mcthomps@us.ibm.com> 9 * Tyler Hicks <tyhicks@ou.edu> 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License as 13 * published by the Free Software Foundation; either version 2 of the 14 * License, or (at your option) any later version. 15 * 16 * This program is distributed in the hope that it will be useful, but 17 * WITHOUT ANY WARRANTY; without even the implied warranty of 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 19 * General Public License for more details. 20 * 21 * You should have received a copy of the GNU General Public License 22 * along with this program; if not, write to the Free Software 23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 24 * 02111-1307, USA. 25 */ 26 27 #include <linux/dcache.h> 28 #include <linux/file.h> 29 #include <linux/module.h> 30 #include <linux/namei.h> 31 #include <linux/skbuff.h> 32 #include <linux/mount.h> 33 #include <linux/pagemap.h> 34 #include <linux/key.h> 35 #include <linux/parser.h> 36 #include <linux/fs_stack.h> 37 #include <linux/slab.h> 38 #include <linux/magic.h> 39 #include "ecryptfs_kernel.h" 40 41 /** 42 * Module parameter that defines the ecryptfs_verbosity level. 43 */ 44 int ecryptfs_verbosity = 0; 45 46 module_param(ecryptfs_verbosity, int, 0); 47 MODULE_PARM_DESC(ecryptfs_verbosity, 48 "Initial verbosity level (0 or 1; defaults to " 49 "0, which is Quiet)"); 50 51 /** 52 * Module parameter that defines the number of message buffer elements 53 */ 54 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS; 55 56 module_param(ecryptfs_message_buf_len, uint, 0); 57 MODULE_PARM_DESC(ecryptfs_message_buf_len, 58 "Number of message buffer elements"); 59 60 /** 61 * Module parameter that defines the maximum guaranteed amount of time to wait 62 * for a response from ecryptfsd. The actual sleep time will be, more than 63 * likely, a small amount greater than this specified value, but only less if 64 * the message successfully arrives. 65 */ 66 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ; 67 68 module_param(ecryptfs_message_wait_timeout, long, 0); 69 MODULE_PARM_DESC(ecryptfs_message_wait_timeout, 70 "Maximum number of seconds that an operation will " 71 "sleep while waiting for a message response from " 72 "userspace"); 73 74 /** 75 * Module parameter that is an estimate of the maximum number of users 76 * that will be concurrently using eCryptfs. Set this to the right 77 * value to balance performance and memory use. 78 */ 79 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS; 80 81 module_param(ecryptfs_number_of_users, uint, 0); 82 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of " 83 "concurrent users of eCryptfs"); 84 85 void __ecryptfs_printk(const char *fmt, ...) 86 { 87 va_list args; 88 va_start(args, fmt); 89 if (fmt[1] == '7') { /* KERN_DEBUG */ 90 if (ecryptfs_verbosity >= 1) 91 vprintk(fmt, args); 92 } else 93 vprintk(fmt, args); 94 va_end(args); 95 } 96 97 /** 98 * ecryptfs_init_lower_file 99 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with 100 * the lower dentry and the lower mount set 101 * 102 * eCryptfs only ever keeps a single open file for every lower 103 * inode. All I/O operations to the lower inode occur through that 104 * file. When the first eCryptfs dentry that interposes with the first 105 * lower dentry for that inode is created, this function creates the 106 * lower file struct and associates it with the eCryptfs 107 * inode. When all eCryptfs files associated with the inode are released, the 108 * file is closed. 109 * 110 * The lower file will be opened with read/write permissions, if 111 * possible. Otherwise, it is opened read-only. 112 * 113 * This function does nothing if a lower file is already 114 * associated with the eCryptfs inode. 115 * 116 * Returns zero on success; non-zero otherwise 117 */ 118 static int ecryptfs_init_lower_file(struct dentry *dentry, 119 struct file **lower_file) 120 { 121 const struct cred *cred = current_cred(); 122 struct path *path = ecryptfs_dentry_to_lower_path(dentry); 123 int rc; 124 125 rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt, 126 cred); 127 if (rc) { 128 printk(KERN_ERR "Error opening lower file " 129 "for lower_dentry [0x%p] and lower_mnt [0x%p]; " 130 "rc = [%d]\n", path->dentry, path->mnt, rc); 131 (*lower_file) = NULL; 132 } 133 return rc; 134 } 135 136 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode) 137 { 138 struct ecryptfs_inode_info *inode_info; 139 int count, rc = 0; 140 141 inode_info = ecryptfs_inode_to_private(inode); 142 mutex_lock(&inode_info->lower_file_mutex); 143 count = atomic_inc_return(&inode_info->lower_file_count); 144 if (WARN_ON_ONCE(count < 1)) 145 rc = -EINVAL; 146 else if (count == 1) { 147 rc = ecryptfs_init_lower_file(dentry, 148 &inode_info->lower_file); 149 if (rc) 150 atomic_set(&inode_info->lower_file_count, 0); 151 } 152 mutex_unlock(&inode_info->lower_file_mutex); 153 return rc; 154 } 155 156 void ecryptfs_put_lower_file(struct inode *inode) 157 { 158 struct ecryptfs_inode_info *inode_info; 159 160 inode_info = ecryptfs_inode_to_private(inode); 161 if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count, 162 &inode_info->lower_file_mutex)) { 163 filemap_write_and_wait(inode->i_mapping); 164 fput(inode_info->lower_file); 165 inode_info->lower_file = NULL; 166 mutex_unlock(&inode_info->lower_file_mutex); 167 } 168 } 169 170 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig, 171 ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher, 172 ecryptfs_opt_ecryptfs_key_bytes, 173 ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata, 174 ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig, 175 ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes, 176 ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only, 177 ecryptfs_opt_check_dev_ruid, 178 ecryptfs_opt_err }; 179 180 static const match_table_t tokens = { 181 {ecryptfs_opt_sig, "sig=%s"}, 182 {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"}, 183 {ecryptfs_opt_cipher, "cipher=%s"}, 184 {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"}, 185 {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"}, 186 {ecryptfs_opt_passthrough, "ecryptfs_passthrough"}, 187 {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"}, 188 {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"}, 189 {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"}, 190 {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"}, 191 {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"}, 192 {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"}, 193 {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"}, 194 {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"}, 195 {ecryptfs_opt_err, NULL} 196 }; 197 198 static int ecryptfs_init_global_auth_toks( 199 struct ecryptfs_mount_crypt_stat *mount_crypt_stat) 200 { 201 struct ecryptfs_global_auth_tok *global_auth_tok; 202 struct ecryptfs_auth_tok *auth_tok; 203 int rc = 0; 204 205 list_for_each_entry(global_auth_tok, 206 &mount_crypt_stat->global_auth_tok_list, 207 mount_crypt_stat_list) { 208 rc = ecryptfs_keyring_auth_tok_for_sig( 209 &global_auth_tok->global_auth_tok_key, &auth_tok, 210 global_auth_tok->sig); 211 if (rc) { 212 printk(KERN_ERR "Could not find valid key in user " 213 "session keyring for sig specified in mount " 214 "option: [%s]\n", global_auth_tok->sig); 215 global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID; 216 goto out; 217 } else { 218 global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID; 219 up_write(&(global_auth_tok->global_auth_tok_key)->sem); 220 } 221 } 222 out: 223 return rc; 224 } 225 226 static void ecryptfs_init_mount_crypt_stat( 227 struct ecryptfs_mount_crypt_stat *mount_crypt_stat) 228 { 229 memset((void *)mount_crypt_stat, 0, 230 sizeof(struct ecryptfs_mount_crypt_stat)); 231 INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list); 232 mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex); 233 mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED; 234 } 235 236 /** 237 * ecryptfs_parse_options 238 * @sb: The ecryptfs super block 239 * @options: The options passed to the kernel 240 * @check_ruid: set to 1 if device uid should be checked against the ruid 241 * 242 * Parse mount options: 243 * debug=N - ecryptfs_verbosity level for debug output 244 * sig=XXX - description(signature) of the key to use 245 * 246 * Returns the dentry object of the lower-level (lower/interposed) 247 * directory; We want to mount our stackable file system on top of 248 * that lower directory. 249 * 250 * The signature of the key to use must be the description of a key 251 * already in the keyring. Mounting will fail if the key can not be 252 * found. 253 * 254 * Returns zero on success; non-zero on error 255 */ 256 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options, 257 uid_t *check_ruid) 258 { 259 char *p; 260 int rc = 0; 261 int sig_set = 0; 262 int cipher_name_set = 0; 263 int fn_cipher_name_set = 0; 264 int cipher_key_bytes; 265 int cipher_key_bytes_set = 0; 266 int fn_cipher_key_bytes; 267 int fn_cipher_key_bytes_set = 0; 268 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 269 &sbi->mount_crypt_stat; 270 substring_t args[MAX_OPT_ARGS]; 271 int token; 272 char *sig_src; 273 char *cipher_name_dst; 274 char *cipher_name_src; 275 char *fn_cipher_name_dst; 276 char *fn_cipher_name_src; 277 char *fnek_dst; 278 char *fnek_src; 279 char *cipher_key_bytes_src; 280 char *fn_cipher_key_bytes_src; 281 u8 cipher_code; 282 283 *check_ruid = 0; 284 285 if (!options) { 286 rc = -EINVAL; 287 goto out; 288 } 289 ecryptfs_init_mount_crypt_stat(mount_crypt_stat); 290 while ((p = strsep(&options, ",")) != NULL) { 291 if (!*p) 292 continue; 293 token = match_token(p, tokens, args); 294 switch (token) { 295 case ecryptfs_opt_sig: 296 case ecryptfs_opt_ecryptfs_sig: 297 sig_src = args[0].from; 298 rc = ecryptfs_add_global_auth_tok(mount_crypt_stat, 299 sig_src, 0); 300 if (rc) { 301 printk(KERN_ERR "Error attempting to register " 302 "global sig; rc = [%d]\n", rc); 303 goto out; 304 } 305 sig_set = 1; 306 break; 307 case ecryptfs_opt_cipher: 308 case ecryptfs_opt_ecryptfs_cipher: 309 cipher_name_src = args[0].from; 310 cipher_name_dst = 311 mount_crypt_stat-> 312 global_default_cipher_name; 313 strncpy(cipher_name_dst, cipher_name_src, 314 ECRYPTFS_MAX_CIPHER_NAME_SIZE); 315 cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; 316 cipher_name_set = 1; 317 break; 318 case ecryptfs_opt_ecryptfs_key_bytes: 319 cipher_key_bytes_src = args[0].from; 320 cipher_key_bytes = 321 (int)simple_strtol(cipher_key_bytes_src, 322 &cipher_key_bytes_src, 0); 323 mount_crypt_stat->global_default_cipher_key_size = 324 cipher_key_bytes; 325 cipher_key_bytes_set = 1; 326 break; 327 case ecryptfs_opt_passthrough: 328 mount_crypt_stat->flags |= 329 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED; 330 break; 331 case ecryptfs_opt_xattr_metadata: 332 mount_crypt_stat->flags |= 333 ECRYPTFS_XATTR_METADATA_ENABLED; 334 break; 335 case ecryptfs_opt_encrypted_view: 336 mount_crypt_stat->flags |= 337 ECRYPTFS_XATTR_METADATA_ENABLED; 338 mount_crypt_stat->flags |= 339 ECRYPTFS_ENCRYPTED_VIEW_ENABLED; 340 break; 341 case ecryptfs_opt_fnek_sig: 342 fnek_src = args[0].from; 343 fnek_dst = 344 mount_crypt_stat->global_default_fnek_sig; 345 strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX); 346 mount_crypt_stat->global_default_fnek_sig[ 347 ECRYPTFS_SIG_SIZE_HEX] = '\0'; 348 rc = ecryptfs_add_global_auth_tok( 349 mount_crypt_stat, 350 mount_crypt_stat->global_default_fnek_sig, 351 ECRYPTFS_AUTH_TOK_FNEK); 352 if (rc) { 353 printk(KERN_ERR "Error attempting to register " 354 "global fnek sig [%s]; rc = [%d]\n", 355 mount_crypt_stat->global_default_fnek_sig, 356 rc); 357 goto out; 358 } 359 mount_crypt_stat->flags |= 360 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES 361 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK); 362 break; 363 case ecryptfs_opt_fn_cipher: 364 fn_cipher_name_src = args[0].from; 365 fn_cipher_name_dst = 366 mount_crypt_stat->global_default_fn_cipher_name; 367 strncpy(fn_cipher_name_dst, fn_cipher_name_src, 368 ECRYPTFS_MAX_CIPHER_NAME_SIZE); 369 mount_crypt_stat->global_default_fn_cipher_name[ 370 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; 371 fn_cipher_name_set = 1; 372 break; 373 case ecryptfs_opt_fn_cipher_key_bytes: 374 fn_cipher_key_bytes_src = args[0].from; 375 fn_cipher_key_bytes = 376 (int)simple_strtol(fn_cipher_key_bytes_src, 377 &fn_cipher_key_bytes_src, 0); 378 mount_crypt_stat->global_default_fn_cipher_key_bytes = 379 fn_cipher_key_bytes; 380 fn_cipher_key_bytes_set = 1; 381 break; 382 case ecryptfs_opt_unlink_sigs: 383 mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS; 384 break; 385 case ecryptfs_opt_mount_auth_tok_only: 386 mount_crypt_stat->flags |= 387 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY; 388 break; 389 case ecryptfs_opt_check_dev_ruid: 390 *check_ruid = 1; 391 break; 392 case ecryptfs_opt_err: 393 default: 394 printk(KERN_WARNING 395 "%s: eCryptfs: unrecognized option [%s]\n", 396 __func__, p); 397 } 398 } 399 if (!sig_set) { 400 rc = -EINVAL; 401 ecryptfs_printk(KERN_ERR, "You must supply at least one valid " 402 "auth tok signature as a mount " 403 "parameter; see the eCryptfs README\n"); 404 goto out; 405 } 406 if (!cipher_name_set) { 407 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER); 408 409 BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE); 410 strcpy(mount_crypt_stat->global_default_cipher_name, 411 ECRYPTFS_DEFAULT_CIPHER); 412 } 413 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) 414 && !fn_cipher_name_set) 415 strcpy(mount_crypt_stat->global_default_fn_cipher_name, 416 mount_crypt_stat->global_default_cipher_name); 417 if (!cipher_key_bytes_set) 418 mount_crypt_stat->global_default_cipher_key_size = 0; 419 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) 420 && !fn_cipher_key_bytes_set) 421 mount_crypt_stat->global_default_fn_cipher_key_bytes = 422 mount_crypt_stat->global_default_cipher_key_size; 423 424 cipher_code = ecryptfs_code_for_cipher_string( 425 mount_crypt_stat->global_default_cipher_name, 426 mount_crypt_stat->global_default_cipher_key_size); 427 if (!cipher_code) { 428 ecryptfs_printk(KERN_ERR, 429 "eCryptfs doesn't support cipher: %s", 430 mount_crypt_stat->global_default_cipher_name); 431 rc = -EINVAL; 432 goto out; 433 } 434 435 mutex_lock(&key_tfm_list_mutex); 436 if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name, 437 NULL)) { 438 rc = ecryptfs_add_new_key_tfm( 439 NULL, mount_crypt_stat->global_default_cipher_name, 440 mount_crypt_stat->global_default_cipher_key_size); 441 if (rc) { 442 printk(KERN_ERR "Error attempting to initialize " 443 "cipher with name = [%s] and key size = [%td]; " 444 "rc = [%d]\n", 445 mount_crypt_stat->global_default_cipher_name, 446 mount_crypt_stat->global_default_cipher_key_size, 447 rc); 448 rc = -EINVAL; 449 mutex_unlock(&key_tfm_list_mutex); 450 goto out; 451 } 452 } 453 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) 454 && !ecryptfs_tfm_exists( 455 mount_crypt_stat->global_default_fn_cipher_name, NULL)) { 456 rc = ecryptfs_add_new_key_tfm( 457 NULL, mount_crypt_stat->global_default_fn_cipher_name, 458 mount_crypt_stat->global_default_fn_cipher_key_bytes); 459 if (rc) { 460 printk(KERN_ERR "Error attempting to initialize " 461 "cipher with name = [%s] and key size = [%td]; " 462 "rc = [%d]\n", 463 mount_crypt_stat->global_default_fn_cipher_name, 464 mount_crypt_stat->global_default_fn_cipher_key_bytes, 465 rc); 466 rc = -EINVAL; 467 mutex_unlock(&key_tfm_list_mutex); 468 goto out; 469 } 470 } 471 mutex_unlock(&key_tfm_list_mutex); 472 rc = ecryptfs_init_global_auth_toks(mount_crypt_stat); 473 if (rc) 474 printk(KERN_WARNING "One or more global auth toks could not " 475 "properly register; rc = [%d]\n", rc); 476 out: 477 return rc; 478 } 479 480 struct kmem_cache *ecryptfs_sb_info_cache; 481 static struct file_system_type ecryptfs_fs_type; 482 483 /** 484 * ecryptfs_get_sb 485 * @fs_type 486 * @flags 487 * @dev_name: The path to mount over 488 * @raw_data: The options passed into the kernel 489 */ 490 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags, 491 const char *dev_name, void *raw_data) 492 { 493 struct super_block *s; 494 struct ecryptfs_sb_info *sbi; 495 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 496 struct ecryptfs_dentry_info *root_info; 497 const char *err = "Getting sb failed"; 498 struct inode *inode; 499 struct path path; 500 uid_t check_ruid; 501 int rc; 502 503 sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL); 504 if (!sbi) { 505 rc = -ENOMEM; 506 goto out; 507 } 508 509 rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid); 510 if (rc) { 511 err = "Error parsing options"; 512 goto out; 513 } 514 mount_crypt_stat = &sbi->mount_crypt_stat; 515 516 s = sget(fs_type, NULL, set_anon_super, flags, NULL); 517 if (IS_ERR(s)) { 518 rc = PTR_ERR(s); 519 goto out; 520 } 521 522 rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs"); 523 if (rc) 524 goto out1; 525 526 ecryptfs_set_superblock_private(s, sbi); 527 s->s_bdi = &sbi->bdi; 528 529 /* ->kill_sb() will take care of sbi after that point */ 530 sbi = NULL; 531 s->s_op = &ecryptfs_sops; 532 s->s_xattr = ecryptfs_xattr_handlers; 533 s->s_d_op = &ecryptfs_dops; 534 535 err = "Reading sb failed"; 536 rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); 537 if (rc) { 538 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n"); 539 goto out1; 540 } 541 if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) { 542 rc = -EINVAL; 543 printk(KERN_ERR "Mount on filesystem of type " 544 "eCryptfs explicitly disallowed due to " 545 "known incompatibilities\n"); 546 goto out_free; 547 } 548 549 if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) { 550 rc = -EPERM; 551 printk(KERN_ERR "Mount of device (uid: %d) not owned by " 552 "requested user (uid: %d)\n", 553 i_uid_read(d_inode(path.dentry)), 554 from_kuid(&init_user_ns, current_uid())); 555 goto out_free; 556 } 557 558 ecryptfs_set_superblock_lower(s, path.dentry->d_sb); 559 560 /** 561 * Set the POSIX ACL flag based on whether they're enabled in the lower 562 * mount. 563 */ 564 s->s_flags = flags & ~MS_POSIXACL; 565 s->s_flags |= path.dentry->d_sb->s_flags & MS_POSIXACL; 566 567 /** 568 * Force a read-only eCryptfs mount when: 569 * 1) The lower mount is ro 570 * 2) The ecryptfs_encrypted_view mount option is specified 571 */ 572 if (path.dentry->d_sb->s_flags & MS_RDONLY || 573 mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) 574 s->s_flags |= MS_RDONLY; 575 576 s->s_maxbytes = path.dentry->d_sb->s_maxbytes; 577 s->s_blocksize = path.dentry->d_sb->s_blocksize; 578 s->s_magic = ECRYPTFS_SUPER_MAGIC; 579 s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1; 580 581 rc = -EINVAL; 582 if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { 583 pr_err("eCryptfs: maximum fs stacking depth exceeded\n"); 584 goto out_free; 585 } 586 587 inode = ecryptfs_get_inode(d_inode(path.dentry), s); 588 rc = PTR_ERR(inode); 589 if (IS_ERR(inode)) 590 goto out_free; 591 592 s->s_root = d_make_root(inode); 593 if (!s->s_root) { 594 rc = -ENOMEM; 595 goto out_free; 596 } 597 598 rc = -ENOMEM; 599 root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL); 600 if (!root_info) 601 goto out_free; 602 603 /* ->kill_sb() will take care of root_info */ 604 ecryptfs_set_dentry_private(s->s_root, root_info); 605 root_info->lower_path = path; 606 607 s->s_flags |= MS_ACTIVE; 608 return dget(s->s_root); 609 610 out_free: 611 path_put(&path); 612 out1: 613 deactivate_locked_super(s); 614 out: 615 if (sbi) { 616 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat); 617 kmem_cache_free(ecryptfs_sb_info_cache, sbi); 618 } 619 printk(KERN_ERR "%s; rc = [%d]\n", err, rc); 620 return ERR_PTR(rc); 621 } 622 623 /** 624 * ecryptfs_kill_block_super 625 * @sb: The ecryptfs super block 626 * 627 * Used to bring the superblock down and free the private data. 628 */ 629 static void ecryptfs_kill_block_super(struct super_block *sb) 630 { 631 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb); 632 kill_anon_super(sb); 633 if (!sb_info) 634 return; 635 ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat); 636 bdi_destroy(&sb_info->bdi); 637 kmem_cache_free(ecryptfs_sb_info_cache, sb_info); 638 } 639 640 static struct file_system_type ecryptfs_fs_type = { 641 .owner = THIS_MODULE, 642 .name = "ecryptfs", 643 .mount = ecryptfs_mount, 644 .kill_sb = ecryptfs_kill_block_super, 645 .fs_flags = 0 646 }; 647 MODULE_ALIAS_FS("ecryptfs"); 648 649 /** 650 * inode_info_init_once 651 * 652 * Initializes the ecryptfs_inode_info_cache when it is created 653 */ 654 static void 655 inode_info_init_once(void *vptr) 656 { 657 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr; 658 659 inode_init_once(&ei->vfs_inode); 660 } 661 662 static struct ecryptfs_cache_info { 663 struct kmem_cache **cache; 664 const char *name; 665 size_t size; 666 unsigned long flags; 667 void (*ctor)(void *obj); 668 } ecryptfs_cache_infos[] = { 669 { 670 .cache = &ecryptfs_auth_tok_list_item_cache, 671 .name = "ecryptfs_auth_tok_list_item", 672 .size = sizeof(struct ecryptfs_auth_tok_list_item), 673 }, 674 { 675 .cache = &ecryptfs_file_info_cache, 676 .name = "ecryptfs_file_cache", 677 .size = sizeof(struct ecryptfs_file_info), 678 }, 679 { 680 .cache = &ecryptfs_dentry_info_cache, 681 .name = "ecryptfs_dentry_info_cache", 682 .size = sizeof(struct ecryptfs_dentry_info), 683 }, 684 { 685 .cache = &ecryptfs_inode_info_cache, 686 .name = "ecryptfs_inode_cache", 687 .size = sizeof(struct ecryptfs_inode_info), 688 .flags = SLAB_ACCOUNT, 689 .ctor = inode_info_init_once, 690 }, 691 { 692 .cache = &ecryptfs_sb_info_cache, 693 .name = "ecryptfs_sb_cache", 694 .size = sizeof(struct ecryptfs_sb_info), 695 }, 696 { 697 .cache = &ecryptfs_header_cache, 698 .name = "ecryptfs_headers", 699 .size = PAGE_SIZE, 700 }, 701 { 702 .cache = &ecryptfs_xattr_cache, 703 .name = "ecryptfs_xattr_cache", 704 .size = PAGE_SIZE, 705 }, 706 { 707 .cache = &ecryptfs_key_record_cache, 708 .name = "ecryptfs_key_record_cache", 709 .size = sizeof(struct ecryptfs_key_record), 710 }, 711 { 712 .cache = &ecryptfs_key_sig_cache, 713 .name = "ecryptfs_key_sig_cache", 714 .size = sizeof(struct ecryptfs_key_sig), 715 }, 716 { 717 .cache = &ecryptfs_global_auth_tok_cache, 718 .name = "ecryptfs_global_auth_tok_cache", 719 .size = sizeof(struct ecryptfs_global_auth_tok), 720 }, 721 { 722 .cache = &ecryptfs_key_tfm_cache, 723 .name = "ecryptfs_key_tfm_cache", 724 .size = sizeof(struct ecryptfs_key_tfm), 725 }, 726 }; 727 728 static void ecryptfs_free_kmem_caches(void) 729 { 730 int i; 731 732 /* 733 * Make sure all delayed rcu free inodes are flushed before we 734 * destroy cache. 735 */ 736 rcu_barrier(); 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 kmem_cache_destroy(*(info->cache)); 743 } 744 } 745 746 /** 747 * ecryptfs_init_kmem_caches 748 * 749 * Returns zero on success; non-zero otherwise 750 */ 751 static int ecryptfs_init_kmem_caches(void) 752 { 753 int i; 754 755 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) { 756 struct ecryptfs_cache_info *info; 757 758 info = &ecryptfs_cache_infos[i]; 759 *(info->cache) = kmem_cache_create(info->name, info->size, 0, 760 SLAB_HWCACHE_ALIGN | info->flags, info->ctor); 761 if (!*(info->cache)) { 762 ecryptfs_free_kmem_caches(); 763 ecryptfs_printk(KERN_WARNING, "%s: " 764 "kmem_cache_create failed\n", 765 info->name); 766 return -ENOMEM; 767 } 768 } 769 return 0; 770 } 771 772 static struct kobject *ecryptfs_kobj; 773 774 static ssize_t version_show(struct kobject *kobj, 775 struct kobj_attribute *attr, char *buff) 776 { 777 return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK); 778 } 779 780 static struct kobj_attribute version_attr = __ATTR_RO(version); 781 782 static struct attribute *attributes[] = { 783 &version_attr.attr, 784 NULL, 785 }; 786 787 static struct attribute_group attr_group = { 788 .attrs = attributes, 789 }; 790 791 static int do_sysfs_registration(void) 792 { 793 int rc; 794 795 ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj); 796 if (!ecryptfs_kobj) { 797 printk(KERN_ERR "Unable to create ecryptfs kset\n"); 798 rc = -ENOMEM; 799 goto out; 800 } 801 rc = sysfs_create_group(ecryptfs_kobj, &attr_group); 802 if (rc) { 803 printk(KERN_ERR 804 "Unable to create ecryptfs version attributes\n"); 805 kobject_put(ecryptfs_kobj); 806 } 807 out: 808 return rc; 809 } 810 811 static void do_sysfs_unregistration(void) 812 { 813 sysfs_remove_group(ecryptfs_kobj, &attr_group); 814 kobject_put(ecryptfs_kobj); 815 } 816 817 static int __init ecryptfs_init(void) 818 { 819 int rc; 820 821 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) { 822 rc = -EINVAL; 823 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is " 824 "larger than the host's page size, and so " 825 "eCryptfs cannot run on this system. The " 826 "default eCryptfs extent size is [%u] bytes; " 827 "the page size is [%lu] bytes.\n", 828 ECRYPTFS_DEFAULT_EXTENT_SIZE, 829 (unsigned long)PAGE_SIZE); 830 goto out; 831 } 832 rc = ecryptfs_init_kmem_caches(); 833 if (rc) { 834 printk(KERN_ERR 835 "Failed to allocate one or more kmem_cache objects\n"); 836 goto out; 837 } 838 rc = do_sysfs_registration(); 839 if (rc) { 840 printk(KERN_ERR "sysfs registration failed\n"); 841 goto out_free_kmem_caches; 842 } 843 rc = ecryptfs_init_kthread(); 844 if (rc) { 845 printk(KERN_ERR "%s: kthread initialization failed; " 846 "rc = [%d]\n", __func__, rc); 847 goto out_do_sysfs_unregistration; 848 } 849 rc = ecryptfs_init_messaging(); 850 if (rc) { 851 printk(KERN_ERR "Failure occurred while attempting to " 852 "initialize the communications channel to " 853 "ecryptfsd\n"); 854 goto out_destroy_kthread; 855 } 856 rc = ecryptfs_init_crypto(); 857 if (rc) { 858 printk(KERN_ERR "Failure whilst attempting to init crypto; " 859 "rc = [%d]\n", rc); 860 goto out_release_messaging; 861 } 862 rc = register_filesystem(&ecryptfs_fs_type); 863 if (rc) { 864 printk(KERN_ERR "Failed to register filesystem\n"); 865 goto out_destroy_crypto; 866 } 867 if (ecryptfs_verbosity > 0) 868 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values " 869 "will be written to the syslog!\n", ecryptfs_verbosity); 870 871 goto out; 872 out_destroy_crypto: 873 ecryptfs_destroy_crypto(); 874 out_release_messaging: 875 ecryptfs_release_messaging(); 876 out_destroy_kthread: 877 ecryptfs_destroy_kthread(); 878 out_do_sysfs_unregistration: 879 do_sysfs_unregistration(); 880 out_free_kmem_caches: 881 ecryptfs_free_kmem_caches(); 882 out: 883 return rc; 884 } 885 886 static void __exit ecryptfs_exit(void) 887 { 888 int rc; 889 890 rc = ecryptfs_destroy_crypto(); 891 if (rc) 892 printk(KERN_ERR "Failure whilst attempting to destroy crypto; " 893 "rc = [%d]\n", rc); 894 ecryptfs_release_messaging(); 895 ecryptfs_destroy_kthread(); 896 do_sysfs_unregistration(); 897 unregister_filesystem(&ecryptfs_fs_type); 898 ecryptfs_free_kmem_caches(); 899 } 900 901 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>"); 902 MODULE_DESCRIPTION("eCryptfs"); 903 904 MODULE_LICENSE("GPL"); 905 906 module_init(ecryptfs_init) 907 module_exit(ecryptfs_exit) 908