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