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 "ecryptfs_kernel.h" 39 40 /** 41 * Module parameter that defines the ecryptfs_verbosity level. 42 */ 43 int ecryptfs_verbosity = 0; 44 45 module_param(ecryptfs_verbosity, int, 0); 46 MODULE_PARM_DESC(ecryptfs_verbosity, 47 "Initial verbosity level (0 or 1; defaults to " 48 "0, which is Quiet)"); 49 50 /** 51 * Module parameter that defines the number of message buffer elements 52 */ 53 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS; 54 55 module_param(ecryptfs_message_buf_len, uint, 0); 56 MODULE_PARM_DESC(ecryptfs_message_buf_len, 57 "Number of message buffer elements"); 58 59 /** 60 * Module parameter that defines the maximum guaranteed amount of time to wait 61 * for a response from ecryptfsd. The actual sleep time will be, more than 62 * likely, a small amount greater than this specified value, but only less if 63 * the message successfully arrives. 64 */ 65 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ; 66 67 module_param(ecryptfs_message_wait_timeout, long, 0); 68 MODULE_PARM_DESC(ecryptfs_message_wait_timeout, 69 "Maximum number of seconds that an operation will " 70 "sleep while waiting for a message response from " 71 "userspace"); 72 73 /** 74 * Module parameter that is an estimate of the maximum number of users 75 * that will be concurrently using eCryptfs. Set this to the right 76 * value to balance performance and memory use. 77 */ 78 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS; 79 80 module_param(ecryptfs_number_of_users, uint, 0); 81 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of " 82 "concurrent users of eCryptfs"); 83 84 void __ecryptfs_printk(const char *fmt, ...) 85 { 86 va_list args; 87 va_start(args, fmt); 88 if (fmt[1] == '7') { /* KERN_DEBUG */ 89 if (ecryptfs_verbosity >= 1) 90 vprintk(fmt, args); 91 } else 92 vprintk(fmt, args); 93 va_end(args); 94 } 95 96 /** 97 * ecryptfs_init_persistent_file 98 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with 99 * the lower dentry and the lower mount set 100 * 101 * eCryptfs only ever keeps a single open file for every lower 102 * inode. All I/O operations to the lower inode occur through that 103 * file. When the first eCryptfs dentry that interposes with the first 104 * lower dentry for that inode is created, this function creates the 105 * persistent file struct and associates it with the eCryptfs 106 * inode. When the eCryptfs inode is destroyed, the file is closed. 107 * 108 * The persistent file will be opened with read/write permissions, if 109 * possible. Otherwise, it is opened read-only. 110 * 111 * This function does nothing if a lower persistent file is already 112 * associated with the eCryptfs inode. 113 * 114 * Returns zero on success; non-zero otherwise 115 */ 116 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry) 117 { 118 const struct cred *cred = current_cred(); 119 struct ecryptfs_inode_info *inode_info = 120 ecryptfs_inode_to_private(ecryptfs_dentry->d_inode); 121 int rc = 0; 122 123 mutex_lock(&inode_info->lower_file_mutex); 124 if (!inode_info->lower_file) { 125 struct dentry *lower_dentry; 126 struct vfsmount *lower_mnt = 127 ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry); 128 129 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); 130 rc = ecryptfs_privileged_open(&inode_info->lower_file, 131 lower_dentry, lower_mnt, cred); 132 if (rc || IS_ERR(inode_info->lower_file)) { 133 printk(KERN_ERR "Error opening lower persistent file " 134 "for lower_dentry [0x%p] and lower_mnt [0x%p]; " 135 "rc = [%d]\n", lower_dentry, lower_mnt, rc); 136 rc = PTR_ERR(inode_info->lower_file); 137 inode_info->lower_file = NULL; 138 } 139 } 140 mutex_unlock(&inode_info->lower_file_mutex); 141 return rc; 142 } 143 144 /** 145 * ecryptfs_interpose 146 * @lower_dentry: Existing dentry in the lower filesystem 147 * @dentry: ecryptfs' dentry 148 * @sb: ecryptfs's super_block 149 * @flags: flags to govern behavior of interpose procedure 150 * 151 * Interposes upper and lower dentries. 152 * 153 * Returns zero on success; non-zero otherwise 154 */ 155 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry, 156 struct super_block *sb, u32 flags) 157 { 158 struct inode *lower_inode; 159 struct inode *inode; 160 int rc = 0; 161 162 lower_inode = lower_dentry->d_inode; 163 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) { 164 rc = -EXDEV; 165 goto out; 166 } 167 if (!igrab(lower_inode)) { 168 rc = -ESTALE; 169 goto out; 170 } 171 inode = iget5_locked(sb, (unsigned long)lower_inode, 172 ecryptfs_inode_test, ecryptfs_inode_set, 173 lower_inode); 174 if (!inode) { 175 rc = -EACCES; 176 iput(lower_inode); 177 goto out; 178 } 179 if (inode->i_state & I_NEW) 180 unlock_new_inode(inode); 181 else 182 iput(lower_inode); 183 if (S_ISLNK(lower_inode->i_mode)) 184 inode->i_op = &ecryptfs_symlink_iops; 185 else if (S_ISDIR(lower_inode->i_mode)) 186 inode->i_op = &ecryptfs_dir_iops; 187 if (S_ISDIR(lower_inode->i_mode)) 188 inode->i_fop = &ecryptfs_dir_fops; 189 if (special_file(lower_inode->i_mode)) 190 init_special_inode(inode, lower_inode->i_mode, 191 lower_inode->i_rdev); 192 dentry->d_op = &ecryptfs_dops; 193 if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD) 194 d_add(dentry, inode); 195 else 196 d_instantiate(dentry, inode); 197 fsstack_copy_attr_all(inode, lower_inode, NULL); 198 /* This size will be overwritten for real files w/ headers and 199 * other metadata */ 200 fsstack_copy_inode_size(inode, lower_inode); 201 out: 202 return rc; 203 } 204 205 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig, 206 ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher, 207 ecryptfs_opt_ecryptfs_key_bytes, 208 ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata, 209 ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig, 210 ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes, 211 ecryptfs_opt_err }; 212 213 static const match_table_t tokens = { 214 {ecryptfs_opt_sig, "sig=%s"}, 215 {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"}, 216 {ecryptfs_opt_cipher, "cipher=%s"}, 217 {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"}, 218 {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"}, 219 {ecryptfs_opt_passthrough, "ecryptfs_passthrough"}, 220 {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"}, 221 {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"}, 222 {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"}, 223 {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"}, 224 {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"}, 225 {ecryptfs_opt_err, NULL} 226 }; 227 228 static int ecryptfs_init_global_auth_toks( 229 struct ecryptfs_mount_crypt_stat *mount_crypt_stat) 230 { 231 struct ecryptfs_global_auth_tok *global_auth_tok; 232 int rc = 0; 233 234 list_for_each_entry(global_auth_tok, 235 &mount_crypt_stat->global_auth_tok_list, 236 mount_crypt_stat_list) { 237 rc = ecryptfs_keyring_auth_tok_for_sig( 238 &global_auth_tok->global_auth_tok_key, 239 &global_auth_tok->global_auth_tok, 240 global_auth_tok->sig); 241 if (rc) { 242 printk(KERN_ERR "Could not find valid key in user " 243 "session keyring for sig specified in mount " 244 "option: [%s]\n", global_auth_tok->sig); 245 global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID; 246 goto out; 247 } else 248 global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID; 249 } 250 out: 251 return rc; 252 } 253 254 static void ecryptfs_init_mount_crypt_stat( 255 struct ecryptfs_mount_crypt_stat *mount_crypt_stat) 256 { 257 memset((void *)mount_crypt_stat, 0, 258 sizeof(struct ecryptfs_mount_crypt_stat)); 259 INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list); 260 mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex); 261 mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED; 262 } 263 264 /** 265 * ecryptfs_parse_options 266 * @sb: The ecryptfs super block 267 * @options: The options pased to the kernel 268 * 269 * Parse mount options: 270 * debug=N - ecryptfs_verbosity level for debug output 271 * sig=XXX - description(signature) of the key to use 272 * 273 * Returns the dentry object of the lower-level (lower/interposed) 274 * directory; We want to mount our stackable file system on top of 275 * that lower directory. 276 * 277 * The signature of the key to use must be the description of a key 278 * already in the keyring. Mounting will fail if the key can not be 279 * found. 280 * 281 * Returns zero on success; non-zero on error 282 */ 283 static int ecryptfs_parse_options(struct super_block *sb, char *options) 284 { 285 char *p; 286 int rc = 0; 287 int sig_set = 0; 288 int cipher_name_set = 0; 289 int fn_cipher_name_set = 0; 290 int cipher_key_bytes; 291 int cipher_key_bytes_set = 0; 292 int fn_cipher_key_bytes; 293 int fn_cipher_key_bytes_set = 0; 294 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = 295 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; 296 substring_t args[MAX_OPT_ARGS]; 297 int token; 298 char *sig_src; 299 char *cipher_name_dst; 300 char *cipher_name_src; 301 char *fn_cipher_name_dst; 302 char *fn_cipher_name_src; 303 char *fnek_dst; 304 char *fnek_src; 305 char *cipher_key_bytes_src; 306 char *fn_cipher_key_bytes_src; 307 308 if (!options) { 309 rc = -EINVAL; 310 goto out; 311 } 312 ecryptfs_init_mount_crypt_stat(mount_crypt_stat); 313 while ((p = strsep(&options, ",")) != NULL) { 314 if (!*p) 315 continue; 316 token = match_token(p, tokens, args); 317 switch (token) { 318 case ecryptfs_opt_sig: 319 case ecryptfs_opt_ecryptfs_sig: 320 sig_src = args[0].from; 321 rc = ecryptfs_add_global_auth_tok(mount_crypt_stat, 322 sig_src, 0); 323 if (rc) { 324 printk(KERN_ERR "Error attempting to register " 325 "global sig; rc = [%d]\n", rc); 326 goto out; 327 } 328 sig_set = 1; 329 break; 330 case ecryptfs_opt_cipher: 331 case ecryptfs_opt_ecryptfs_cipher: 332 cipher_name_src = args[0].from; 333 cipher_name_dst = 334 mount_crypt_stat-> 335 global_default_cipher_name; 336 strncpy(cipher_name_dst, cipher_name_src, 337 ECRYPTFS_MAX_CIPHER_NAME_SIZE); 338 cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; 339 cipher_name_set = 1; 340 break; 341 case ecryptfs_opt_ecryptfs_key_bytes: 342 cipher_key_bytes_src = args[0].from; 343 cipher_key_bytes = 344 (int)simple_strtol(cipher_key_bytes_src, 345 &cipher_key_bytes_src, 0); 346 mount_crypt_stat->global_default_cipher_key_size = 347 cipher_key_bytes; 348 cipher_key_bytes_set = 1; 349 break; 350 case ecryptfs_opt_passthrough: 351 mount_crypt_stat->flags |= 352 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED; 353 break; 354 case ecryptfs_opt_xattr_metadata: 355 mount_crypt_stat->flags |= 356 ECRYPTFS_XATTR_METADATA_ENABLED; 357 break; 358 case ecryptfs_opt_encrypted_view: 359 mount_crypt_stat->flags |= 360 ECRYPTFS_XATTR_METADATA_ENABLED; 361 mount_crypt_stat->flags |= 362 ECRYPTFS_ENCRYPTED_VIEW_ENABLED; 363 break; 364 case ecryptfs_opt_fnek_sig: 365 fnek_src = args[0].from; 366 fnek_dst = 367 mount_crypt_stat->global_default_fnek_sig; 368 strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX); 369 mount_crypt_stat->global_default_fnek_sig[ 370 ECRYPTFS_SIG_SIZE_HEX] = '\0'; 371 rc = ecryptfs_add_global_auth_tok( 372 mount_crypt_stat, 373 mount_crypt_stat->global_default_fnek_sig, 374 ECRYPTFS_AUTH_TOK_FNEK); 375 if (rc) { 376 printk(KERN_ERR "Error attempting to register " 377 "global fnek sig [%s]; rc = [%d]\n", 378 mount_crypt_stat->global_default_fnek_sig, 379 rc); 380 goto out; 381 } 382 mount_crypt_stat->flags |= 383 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES 384 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK); 385 break; 386 case ecryptfs_opt_fn_cipher: 387 fn_cipher_name_src = args[0].from; 388 fn_cipher_name_dst = 389 mount_crypt_stat->global_default_fn_cipher_name; 390 strncpy(fn_cipher_name_dst, fn_cipher_name_src, 391 ECRYPTFS_MAX_CIPHER_NAME_SIZE); 392 mount_crypt_stat->global_default_fn_cipher_name[ 393 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; 394 fn_cipher_name_set = 1; 395 break; 396 case ecryptfs_opt_fn_cipher_key_bytes: 397 fn_cipher_key_bytes_src = args[0].from; 398 fn_cipher_key_bytes = 399 (int)simple_strtol(fn_cipher_key_bytes_src, 400 &fn_cipher_key_bytes_src, 0); 401 mount_crypt_stat->global_default_fn_cipher_key_bytes = 402 fn_cipher_key_bytes; 403 fn_cipher_key_bytes_set = 1; 404 break; 405 case ecryptfs_opt_err: 406 default: 407 printk(KERN_WARNING 408 "%s: eCryptfs: unrecognized option [%s]\n", 409 __func__, p); 410 } 411 } 412 if (!sig_set) { 413 rc = -EINVAL; 414 ecryptfs_printk(KERN_ERR, "You must supply at least one valid " 415 "auth tok signature as a mount " 416 "parameter; see the eCryptfs README\n"); 417 goto out; 418 } 419 if (!cipher_name_set) { 420 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER); 421 422 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE); 423 strcpy(mount_crypt_stat->global_default_cipher_name, 424 ECRYPTFS_DEFAULT_CIPHER); 425 } 426 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) 427 && !fn_cipher_name_set) 428 strcpy(mount_crypt_stat->global_default_fn_cipher_name, 429 mount_crypt_stat->global_default_cipher_name); 430 if (!cipher_key_bytes_set) 431 mount_crypt_stat->global_default_cipher_key_size = 0; 432 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) 433 && !fn_cipher_key_bytes_set) 434 mount_crypt_stat->global_default_fn_cipher_key_bytes = 435 mount_crypt_stat->global_default_cipher_key_size; 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; 482 483 /** 484 * ecryptfs_fill_super 485 * @sb: The ecryptfs super block 486 * @raw_data: The options passed to mount 487 * @silent: Not used but required by function prototype 488 * 489 * Sets up what we can of the sb, rest is done in ecryptfs_read_super 490 * 491 * Returns zero on success; non-zero otherwise 492 */ 493 static int 494 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent) 495 { 496 int rc = 0; 497 498 /* Released in ecryptfs_put_super() */ 499 ecryptfs_set_superblock_private(sb, 500 kmem_cache_zalloc(ecryptfs_sb_info_cache, 501 GFP_KERNEL)); 502 if (!ecryptfs_superblock_to_private(sb)) { 503 ecryptfs_printk(KERN_WARNING, "Out of memory\n"); 504 rc = -ENOMEM; 505 goto out; 506 } 507 sb->s_op = &ecryptfs_sops; 508 /* Released through deactivate_super(sb) from get_sb_nodev */ 509 sb->s_root = d_alloc(NULL, &(const struct qstr) { 510 .hash = 0,.name = "/",.len = 1}); 511 if (!sb->s_root) { 512 ecryptfs_printk(KERN_ERR, "d_alloc failed\n"); 513 rc = -ENOMEM; 514 goto out; 515 } 516 sb->s_root->d_op = &ecryptfs_dops; 517 sb->s_root->d_sb = sb; 518 sb->s_root->d_parent = sb->s_root; 519 /* Released in d_release when dput(sb->s_root) is called */ 520 /* through deactivate_super(sb) from get_sb_nodev() */ 521 ecryptfs_set_dentry_private(sb->s_root, 522 kmem_cache_zalloc(ecryptfs_dentry_info_cache, 523 GFP_KERNEL)); 524 if (!ecryptfs_dentry_to_private(sb->s_root)) { 525 ecryptfs_printk(KERN_ERR, 526 "dentry_info_cache alloc failed\n"); 527 rc = -ENOMEM; 528 goto out; 529 } 530 rc = 0; 531 out: 532 /* Should be able to rely on deactivate_super called from 533 * get_sb_nodev */ 534 return rc; 535 } 536 537 /** 538 * ecryptfs_read_super 539 * @sb: The ecryptfs super block 540 * @dev_name: The path to mount over 541 * 542 * Read the super block of the lower filesystem, and use 543 * ecryptfs_interpose to create our initial inode and super block 544 * struct. 545 */ 546 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name) 547 { 548 struct path path; 549 int rc; 550 551 rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); 552 if (rc) { 553 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n"); 554 goto out; 555 } 556 ecryptfs_set_superblock_lower(sb, path.dentry->d_sb); 557 sb->s_maxbytes = path.dentry->d_sb->s_maxbytes; 558 sb->s_blocksize = path.dentry->d_sb->s_blocksize; 559 ecryptfs_set_dentry_lower(sb->s_root, path.dentry); 560 ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt); 561 rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0); 562 if (rc) 563 goto out_free; 564 rc = 0; 565 goto out; 566 out_free: 567 path_put(&path); 568 out: 569 return rc; 570 } 571 572 /** 573 * ecryptfs_get_sb 574 * @fs_type 575 * @flags 576 * @dev_name: The path to mount over 577 * @raw_data: The options passed into the kernel 578 * 579 * The whole ecryptfs_get_sb process is broken into 4 functions: 580 * ecryptfs_parse_options(): handle options passed to ecryptfs, if any 581 * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block 582 * with as much information as it can before needing 583 * the lower filesystem. 584 * ecryptfs_read_super(): this accesses the lower filesystem and uses 585 * ecryptfs_interpolate to perform most of the linking 586 * ecryptfs_interpolate(): links the lower filesystem into ecryptfs 587 */ 588 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags, 589 const char *dev_name, void *raw_data, 590 struct vfsmount *mnt) 591 { 592 int rc; 593 struct super_block *sb; 594 595 rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt); 596 if (rc < 0) { 597 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc); 598 goto out; 599 } 600 sb = mnt->mnt_sb; 601 rc = ecryptfs_parse_options(sb, raw_data); 602 if (rc) { 603 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc); 604 goto out_abort; 605 } 606 rc = ecryptfs_read_super(sb, dev_name); 607 if (rc) { 608 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc); 609 goto out_abort; 610 } 611 goto out; 612 out_abort: 613 dput(sb->s_root); 614 up_write(&sb->s_umount); 615 deactivate_super(sb); 616 out: 617 return rc; 618 } 619 620 /** 621 * ecryptfs_kill_block_super 622 * @sb: The ecryptfs super block 623 * 624 * Used to bring the superblock down and free the private data. 625 * Private data is free'd in ecryptfs_put_super() 626 */ 627 static void ecryptfs_kill_block_super(struct super_block *sb) 628 { 629 generic_shutdown_super(sb); 630 } 631 632 static struct file_system_type ecryptfs_fs_type = { 633 .owner = THIS_MODULE, 634 .name = "ecryptfs", 635 .get_sb = ecryptfs_get_sb, 636 .kill_sb = ecryptfs_kill_block_super, 637 .fs_flags = 0 638 }; 639 640 /** 641 * inode_info_init_once 642 * 643 * Initializes the ecryptfs_inode_info_cache when it is created 644 */ 645 static void 646 inode_info_init_once(void *vptr) 647 { 648 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr; 649 650 inode_init_once(&ei->vfs_inode); 651 } 652 653 static struct ecryptfs_cache_info { 654 struct kmem_cache **cache; 655 const char *name; 656 size_t size; 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 .ctor = inode_info_init_once, 679 }, 680 { 681 .cache = &ecryptfs_sb_info_cache, 682 .name = "ecryptfs_sb_cache", 683 .size = sizeof(struct ecryptfs_sb_info), 684 }, 685 { 686 .cache = &ecryptfs_header_cache_1, 687 .name = "ecryptfs_headers_1", 688 .size = PAGE_CACHE_SIZE, 689 }, 690 { 691 .cache = &ecryptfs_header_cache_2, 692 .name = "ecryptfs_headers_2", 693 .size = PAGE_CACHE_SIZE, 694 }, 695 { 696 .cache = &ecryptfs_xattr_cache, 697 .name = "ecryptfs_xattr_cache", 698 .size = PAGE_CACHE_SIZE, 699 }, 700 { 701 .cache = &ecryptfs_key_record_cache, 702 .name = "ecryptfs_key_record_cache", 703 .size = sizeof(struct ecryptfs_key_record), 704 }, 705 { 706 .cache = &ecryptfs_key_sig_cache, 707 .name = "ecryptfs_key_sig_cache", 708 .size = sizeof(struct ecryptfs_key_sig), 709 }, 710 { 711 .cache = &ecryptfs_global_auth_tok_cache, 712 .name = "ecryptfs_global_auth_tok_cache", 713 .size = sizeof(struct ecryptfs_global_auth_tok), 714 }, 715 { 716 .cache = &ecryptfs_key_tfm_cache, 717 .name = "ecryptfs_key_tfm_cache", 718 .size = sizeof(struct ecryptfs_key_tfm), 719 }, 720 { 721 .cache = &ecryptfs_open_req_cache, 722 .name = "ecryptfs_open_req_cache", 723 .size = sizeof(struct ecryptfs_open_req), 724 }, 725 }; 726 727 static void ecryptfs_free_kmem_caches(void) 728 { 729 int i; 730 731 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) { 732 struct ecryptfs_cache_info *info; 733 734 info = &ecryptfs_cache_infos[i]; 735 if (*(info->cache)) 736 kmem_cache_destroy(*(info->cache)); 737 } 738 } 739 740 /** 741 * ecryptfs_init_kmem_caches 742 * 743 * Returns zero on success; non-zero otherwise 744 */ 745 static int ecryptfs_init_kmem_caches(void) 746 { 747 int i; 748 749 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) { 750 struct ecryptfs_cache_info *info; 751 752 info = &ecryptfs_cache_infos[i]; 753 *(info->cache) = kmem_cache_create(info->name, info->size, 754 0, SLAB_HWCACHE_ALIGN, info->ctor); 755 if (!*(info->cache)) { 756 ecryptfs_free_kmem_caches(); 757 ecryptfs_printk(KERN_WARNING, "%s: " 758 "kmem_cache_create failed\n", 759 info->name); 760 return -ENOMEM; 761 } 762 } 763 return 0; 764 } 765 766 static struct kobject *ecryptfs_kobj; 767 768 static ssize_t version_show(struct kobject *kobj, 769 struct kobj_attribute *attr, char *buff) 770 { 771 return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK); 772 } 773 774 static struct kobj_attribute version_attr = __ATTR_RO(version); 775 776 static struct attribute *attributes[] = { 777 &version_attr.attr, 778 NULL, 779 }; 780 781 static struct attribute_group attr_group = { 782 .attrs = attributes, 783 }; 784 785 static int do_sysfs_registration(void) 786 { 787 int rc; 788 789 ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj); 790 if (!ecryptfs_kobj) { 791 printk(KERN_ERR "Unable to create ecryptfs kset\n"); 792 rc = -ENOMEM; 793 goto out; 794 } 795 rc = sysfs_create_group(ecryptfs_kobj, &attr_group); 796 if (rc) { 797 printk(KERN_ERR 798 "Unable to create ecryptfs version attributes\n"); 799 kobject_put(ecryptfs_kobj); 800 } 801 out: 802 return rc; 803 } 804 805 static void do_sysfs_unregistration(void) 806 { 807 sysfs_remove_group(ecryptfs_kobj, &attr_group); 808 kobject_put(ecryptfs_kobj); 809 } 810 811 static int __init ecryptfs_init(void) 812 { 813 int rc; 814 815 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) { 816 rc = -EINVAL; 817 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is " 818 "larger than the host's page size, and so " 819 "eCryptfs cannot run on this system. The " 820 "default eCryptfs extent size is [%d] bytes; " 821 "the page size is [%d] bytes.\n", 822 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE); 823 goto out; 824 } 825 rc = ecryptfs_init_kmem_caches(); 826 if (rc) { 827 printk(KERN_ERR 828 "Failed to allocate one or more kmem_cache objects\n"); 829 goto out; 830 } 831 rc = register_filesystem(&ecryptfs_fs_type); 832 if (rc) { 833 printk(KERN_ERR "Failed to register filesystem\n"); 834 goto out_free_kmem_caches; 835 } 836 rc = do_sysfs_registration(); 837 if (rc) { 838 printk(KERN_ERR "sysfs registration failed\n"); 839 goto out_unregister_filesystem; 840 } 841 rc = ecryptfs_init_kthread(); 842 if (rc) { 843 printk(KERN_ERR "%s: kthread initialization failed; " 844 "rc = [%d]\n", __func__, rc); 845 goto out_do_sysfs_unregistration; 846 } 847 rc = ecryptfs_init_messaging(); 848 if (rc) { 849 printk(KERN_ERR "Failure occured while attempting to " 850 "initialize the communications channel to " 851 "ecryptfsd\n"); 852 goto out_destroy_kthread; 853 } 854 rc = ecryptfs_init_crypto(); 855 if (rc) { 856 printk(KERN_ERR "Failure whilst attempting to init crypto; " 857 "rc = [%d]\n", rc); 858 goto out_release_messaging; 859 } 860 if (ecryptfs_verbosity > 0) 861 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values " 862 "will be written to the syslog!\n", ecryptfs_verbosity); 863 864 goto out; 865 out_release_messaging: 866 ecryptfs_release_messaging(); 867 out_destroy_kthread: 868 ecryptfs_destroy_kthread(); 869 out_do_sysfs_unregistration: 870 do_sysfs_unregistration(); 871 out_unregister_filesystem: 872 unregister_filesystem(&ecryptfs_fs_type); 873 out_free_kmem_caches: 874 ecryptfs_free_kmem_caches(); 875 out: 876 return rc; 877 } 878 879 static void __exit ecryptfs_exit(void) 880 { 881 int rc; 882 883 rc = ecryptfs_destroy_crypto(); 884 if (rc) 885 printk(KERN_ERR "Failure whilst attempting to destroy crypto; " 886 "rc = [%d]\n", rc); 887 ecryptfs_release_messaging(); 888 ecryptfs_destroy_kthread(); 889 do_sysfs_unregistration(); 890 unregister_filesystem(&ecryptfs_fs_type); 891 ecryptfs_free_kmem_caches(); 892 } 893 894 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>"); 895 MODULE_DESCRIPTION("eCryptfs"); 896 897 MODULE_LICENSE("GPL"); 898 899 module_init(ecryptfs_init) 900 module_exit(ecryptfs_exit) 901