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) { 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 inode_info->lower_file = NULL; 137 } 138 } 139 mutex_unlock(&inode_info->lower_file_mutex); 140 return rc; 141 } 142 143 /** 144 * ecryptfs_interpose 145 * @lower_dentry: Existing dentry in the lower filesystem 146 * @dentry: ecryptfs' dentry 147 * @sb: ecryptfs's super_block 148 * @flags: flags to govern behavior of interpose procedure 149 * 150 * Interposes upper and lower dentries. 151 * 152 * Returns zero on success; non-zero otherwise 153 */ 154 int ecryptfs_interpose(struct dentry *lower_dentry, struct dentry *dentry, 155 struct super_block *sb, u32 flags) 156 { 157 struct inode *lower_inode; 158 struct inode *inode; 159 int rc = 0; 160 161 lower_inode = lower_dentry->d_inode; 162 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) { 163 rc = -EXDEV; 164 goto out; 165 } 166 if (!igrab(lower_inode)) { 167 rc = -ESTALE; 168 goto out; 169 } 170 inode = iget5_locked(sb, (unsigned long)lower_inode, 171 ecryptfs_inode_test, ecryptfs_inode_set, 172 lower_inode); 173 if (!inode) { 174 rc = -EACCES; 175 iput(lower_inode); 176 goto out; 177 } 178 if (inode->i_state & I_NEW) 179 unlock_new_inode(inode); 180 else 181 iput(lower_inode); 182 if (S_ISLNK(lower_inode->i_mode)) 183 inode->i_op = &ecryptfs_symlink_iops; 184 else if (S_ISDIR(lower_inode->i_mode)) 185 inode->i_op = &ecryptfs_dir_iops; 186 if (S_ISDIR(lower_inode->i_mode)) 187 inode->i_fop = &ecryptfs_dir_fops; 188 if (special_file(lower_inode->i_mode)) 189 init_special_inode(inode, lower_inode->i_mode, 190 lower_inode->i_rdev); 191 dentry->d_op = &ecryptfs_dops; 192 fsstack_copy_attr_all(inode, lower_inode); 193 /* This size will be overwritten for real files w/ headers and 194 * other metadata */ 195 fsstack_copy_inode_size(inode, lower_inode); 196 if (flags & ECRYPTFS_INTERPOSE_FLAG_D_ADD) 197 d_add(dentry, inode); 198 else 199 d_instantiate(dentry, inode); 200 out: 201 return rc; 202 } 203 204 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig, 205 ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher, 206 ecryptfs_opt_ecryptfs_key_bytes, 207 ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata, 208 ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig, 209 ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes, 210 ecryptfs_opt_unlink_sigs, ecryptfs_opt_err }; 211 212 static const match_table_t tokens = { 213 {ecryptfs_opt_sig, "sig=%s"}, 214 {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"}, 215 {ecryptfs_opt_cipher, "cipher=%s"}, 216 {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"}, 217 {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"}, 218 {ecryptfs_opt_passthrough, "ecryptfs_passthrough"}, 219 {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"}, 220 {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"}, 221 {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"}, 222 {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"}, 223 {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"}, 224 {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"}, 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_unlink_sigs: 406 mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS; 407 break; 408 case ecryptfs_opt_err: 409 default: 410 printk(KERN_WARNING 411 "%s: eCryptfs: unrecognized option [%s]\n", 412 __func__, p); 413 } 414 } 415 if (!sig_set) { 416 rc = -EINVAL; 417 ecryptfs_printk(KERN_ERR, "You must supply at least one valid " 418 "auth tok signature as a mount " 419 "parameter; see the eCryptfs README\n"); 420 goto out; 421 } 422 if (!cipher_name_set) { 423 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER); 424 425 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE); 426 strcpy(mount_crypt_stat->global_default_cipher_name, 427 ECRYPTFS_DEFAULT_CIPHER); 428 } 429 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) 430 && !fn_cipher_name_set) 431 strcpy(mount_crypt_stat->global_default_fn_cipher_name, 432 mount_crypt_stat->global_default_cipher_name); 433 if (!cipher_key_bytes_set) 434 mount_crypt_stat->global_default_cipher_key_size = 0; 435 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) 436 && !fn_cipher_key_bytes_set) 437 mount_crypt_stat->global_default_fn_cipher_key_bytes = 438 mount_crypt_stat->global_default_cipher_key_size; 439 mutex_lock(&key_tfm_list_mutex); 440 if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name, 441 NULL)) { 442 rc = ecryptfs_add_new_key_tfm( 443 NULL, mount_crypt_stat->global_default_cipher_name, 444 mount_crypt_stat->global_default_cipher_key_size); 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_cipher_name, 450 mount_crypt_stat->global_default_cipher_key_size, 451 rc); 452 rc = -EINVAL; 453 mutex_unlock(&key_tfm_list_mutex); 454 goto out; 455 } 456 } 457 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) 458 && !ecryptfs_tfm_exists( 459 mount_crypt_stat->global_default_fn_cipher_name, NULL)) { 460 rc = ecryptfs_add_new_key_tfm( 461 NULL, mount_crypt_stat->global_default_fn_cipher_name, 462 mount_crypt_stat->global_default_fn_cipher_key_bytes); 463 if (rc) { 464 printk(KERN_ERR "Error attempting to initialize " 465 "cipher with name = [%s] and key size = [%td]; " 466 "rc = [%d]\n", 467 mount_crypt_stat->global_default_fn_cipher_name, 468 mount_crypt_stat->global_default_fn_cipher_key_bytes, 469 rc); 470 rc = -EINVAL; 471 mutex_unlock(&key_tfm_list_mutex); 472 goto out; 473 } 474 } 475 mutex_unlock(&key_tfm_list_mutex); 476 rc = ecryptfs_init_global_auth_toks(mount_crypt_stat); 477 if (rc) 478 printk(KERN_WARNING "One or more global auth toks could not " 479 "properly register; rc = [%d]\n", rc); 480 out: 481 return rc; 482 } 483 484 struct kmem_cache *ecryptfs_sb_info_cache; 485 486 /** 487 * ecryptfs_fill_super 488 * @sb: The ecryptfs super block 489 * @raw_data: The options passed to mount 490 * @silent: Not used but required by function prototype 491 * 492 * Sets up what we can of the sb, rest is done in ecryptfs_read_super 493 * 494 * Returns zero on success; non-zero otherwise 495 */ 496 static int 497 ecryptfs_fill_super(struct super_block *sb, void *raw_data, int silent) 498 { 499 int rc = 0; 500 501 /* Released in ecryptfs_put_super() */ 502 ecryptfs_set_superblock_private(sb, 503 kmem_cache_zalloc(ecryptfs_sb_info_cache, 504 GFP_KERNEL)); 505 if (!ecryptfs_superblock_to_private(sb)) { 506 ecryptfs_printk(KERN_WARNING, "Out of memory\n"); 507 rc = -ENOMEM; 508 goto out; 509 } 510 sb->s_op = &ecryptfs_sops; 511 /* Released through deactivate_super(sb) from get_sb_nodev */ 512 sb->s_root = d_alloc(NULL, &(const struct qstr) { 513 .hash = 0,.name = "/",.len = 1}); 514 if (!sb->s_root) { 515 ecryptfs_printk(KERN_ERR, "d_alloc failed\n"); 516 rc = -ENOMEM; 517 goto out; 518 } 519 sb->s_root->d_op = &ecryptfs_dops; 520 sb->s_root->d_sb = sb; 521 sb->s_root->d_parent = sb->s_root; 522 /* Released in d_release when dput(sb->s_root) is called */ 523 /* through deactivate_super(sb) from get_sb_nodev() */ 524 ecryptfs_set_dentry_private(sb->s_root, 525 kmem_cache_zalloc(ecryptfs_dentry_info_cache, 526 GFP_KERNEL)); 527 if (!ecryptfs_dentry_to_private(sb->s_root)) { 528 ecryptfs_printk(KERN_ERR, 529 "dentry_info_cache alloc failed\n"); 530 rc = -ENOMEM; 531 goto out; 532 } 533 rc = 0; 534 out: 535 /* Should be able to rely on deactivate_super called from 536 * get_sb_nodev */ 537 return rc; 538 } 539 540 /** 541 * ecryptfs_read_super 542 * @sb: The ecryptfs super block 543 * @dev_name: The path to mount over 544 * 545 * Read the super block of the lower filesystem, and use 546 * ecryptfs_interpose to create our initial inode and super block 547 * struct. 548 */ 549 static int ecryptfs_read_super(struct super_block *sb, const char *dev_name) 550 { 551 struct path path; 552 int rc; 553 554 rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); 555 if (rc) { 556 ecryptfs_printk(KERN_WARNING, "path_lookup() failed\n"); 557 goto out; 558 } 559 ecryptfs_set_superblock_lower(sb, path.dentry->d_sb); 560 sb->s_maxbytes = path.dentry->d_sb->s_maxbytes; 561 sb->s_blocksize = path.dentry->d_sb->s_blocksize; 562 ecryptfs_set_dentry_lower(sb->s_root, path.dentry); 563 ecryptfs_set_dentry_lower_mnt(sb->s_root, path.mnt); 564 rc = ecryptfs_interpose(path.dentry, sb->s_root, sb, 0); 565 if (rc) 566 goto out_free; 567 rc = 0; 568 goto out; 569 out_free: 570 path_put(&path); 571 out: 572 return rc; 573 } 574 575 /** 576 * ecryptfs_get_sb 577 * @fs_type 578 * @flags 579 * @dev_name: The path to mount over 580 * @raw_data: The options passed into the kernel 581 * 582 * The whole ecryptfs_get_sb process is broken into 4 functions: 583 * ecryptfs_parse_options(): handle options passed to ecryptfs, if any 584 * ecryptfs_fill_super(): used by get_sb_nodev, fills out the super_block 585 * with as much information as it can before needing 586 * the lower filesystem. 587 * ecryptfs_read_super(): this accesses the lower filesystem and uses 588 * ecryptfs_interpolate to perform most of the linking 589 * ecryptfs_interpolate(): links the lower filesystem into ecryptfs 590 */ 591 static int ecryptfs_get_sb(struct file_system_type *fs_type, int flags, 592 const char *dev_name, void *raw_data, 593 struct vfsmount *mnt) 594 { 595 int rc; 596 struct super_block *sb; 597 598 rc = get_sb_nodev(fs_type, flags, raw_data, ecryptfs_fill_super, mnt); 599 if (rc < 0) { 600 printk(KERN_ERR "Getting sb failed; rc = [%d]\n", rc); 601 goto out; 602 } 603 sb = mnt->mnt_sb; 604 rc = ecryptfs_parse_options(sb, raw_data); 605 if (rc) { 606 printk(KERN_ERR "Error parsing options; rc = [%d]\n", rc); 607 goto out_abort; 608 } 609 rc = ecryptfs_read_super(sb, dev_name); 610 if (rc) { 611 printk(KERN_ERR "Reading sb failed; rc = [%d]\n", rc); 612 goto out_abort; 613 } 614 goto out; 615 out_abort: 616 dput(sb->s_root); /* aka mnt->mnt_root, as set by get_sb_nodev() */ 617 deactivate_locked_super(sb); 618 out: 619 return rc; 620 } 621 622 /** 623 * ecryptfs_kill_block_super 624 * @sb: The ecryptfs super block 625 * 626 * Used to bring the superblock down and free the private data. 627 * Private data is free'd in ecryptfs_put_super() 628 */ 629 static void ecryptfs_kill_block_super(struct super_block *sb) 630 { 631 generic_shutdown_super(sb); 632 } 633 634 static struct file_system_type ecryptfs_fs_type = { 635 .owner = THIS_MODULE, 636 .name = "ecryptfs", 637 .get_sb = ecryptfs_get_sb, 638 .kill_sb = ecryptfs_kill_block_super, 639 .fs_flags = 0 640 }; 641 642 /** 643 * inode_info_init_once 644 * 645 * Initializes the ecryptfs_inode_info_cache when it is created 646 */ 647 static void 648 inode_info_init_once(void *vptr) 649 { 650 struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr; 651 652 inode_init_once(&ei->vfs_inode); 653 } 654 655 static struct ecryptfs_cache_info { 656 struct kmem_cache **cache; 657 const char *name; 658 size_t size; 659 void (*ctor)(void *obj); 660 } ecryptfs_cache_infos[] = { 661 { 662 .cache = &ecryptfs_auth_tok_list_item_cache, 663 .name = "ecryptfs_auth_tok_list_item", 664 .size = sizeof(struct ecryptfs_auth_tok_list_item), 665 }, 666 { 667 .cache = &ecryptfs_file_info_cache, 668 .name = "ecryptfs_file_cache", 669 .size = sizeof(struct ecryptfs_file_info), 670 }, 671 { 672 .cache = &ecryptfs_dentry_info_cache, 673 .name = "ecryptfs_dentry_info_cache", 674 .size = sizeof(struct ecryptfs_dentry_info), 675 }, 676 { 677 .cache = &ecryptfs_inode_info_cache, 678 .name = "ecryptfs_inode_cache", 679 .size = sizeof(struct ecryptfs_inode_info), 680 .ctor = inode_info_init_once, 681 }, 682 { 683 .cache = &ecryptfs_sb_info_cache, 684 .name = "ecryptfs_sb_cache", 685 .size = sizeof(struct ecryptfs_sb_info), 686 }, 687 { 688 .cache = &ecryptfs_header_cache_1, 689 .name = "ecryptfs_headers_1", 690 .size = PAGE_CACHE_SIZE, 691 }, 692 { 693 .cache = &ecryptfs_header_cache_2, 694 .name = "ecryptfs_headers_2", 695 .size = PAGE_CACHE_SIZE, 696 }, 697 { 698 .cache = &ecryptfs_xattr_cache, 699 .name = "ecryptfs_xattr_cache", 700 .size = PAGE_CACHE_SIZE, 701 }, 702 { 703 .cache = &ecryptfs_key_record_cache, 704 .name = "ecryptfs_key_record_cache", 705 .size = sizeof(struct ecryptfs_key_record), 706 }, 707 { 708 .cache = &ecryptfs_key_sig_cache, 709 .name = "ecryptfs_key_sig_cache", 710 .size = sizeof(struct ecryptfs_key_sig), 711 }, 712 { 713 .cache = &ecryptfs_global_auth_tok_cache, 714 .name = "ecryptfs_global_auth_tok_cache", 715 .size = sizeof(struct ecryptfs_global_auth_tok), 716 }, 717 { 718 .cache = &ecryptfs_key_tfm_cache, 719 .name = "ecryptfs_key_tfm_cache", 720 .size = sizeof(struct ecryptfs_key_tfm), 721 }, 722 { 723 .cache = &ecryptfs_open_req_cache, 724 .name = "ecryptfs_open_req_cache", 725 .size = sizeof(struct ecryptfs_open_req), 726 }, 727 }; 728 729 static void ecryptfs_free_kmem_caches(void) 730 { 731 int i; 732 733 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) { 734 struct ecryptfs_cache_info *info; 735 736 info = &ecryptfs_cache_infos[i]; 737 if (*(info->cache)) 738 kmem_cache_destroy(*(info->cache)); 739 } 740 } 741 742 /** 743 * ecryptfs_init_kmem_caches 744 * 745 * Returns zero on success; non-zero otherwise 746 */ 747 static int ecryptfs_init_kmem_caches(void) 748 { 749 int i; 750 751 for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) { 752 struct ecryptfs_cache_info *info; 753 754 info = &ecryptfs_cache_infos[i]; 755 *(info->cache) = kmem_cache_create(info->name, info->size, 756 0, SLAB_HWCACHE_ALIGN, info->ctor); 757 if (!*(info->cache)) { 758 ecryptfs_free_kmem_caches(); 759 ecryptfs_printk(KERN_WARNING, "%s: " 760 "kmem_cache_create failed\n", 761 info->name); 762 return -ENOMEM; 763 } 764 } 765 return 0; 766 } 767 768 static struct kobject *ecryptfs_kobj; 769 770 static ssize_t version_show(struct kobject *kobj, 771 struct kobj_attribute *attr, char *buff) 772 { 773 return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK); 774 } 775 776 static struct kobj_attribute version_attr = __ATTR_RO(version); 777 778 static struct attribute *attributes[] = { 779 &version_attr.attr, 780 NULL, 781 }; 782 783 static struct attribute_group attr_group = { 784 .attrs = attributes, 785 }; 786 787 static int do_sysfs_registration(void) 788 { 789 int rc; 790 791 ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj); 792 if (!ecryptfs_kobj) { 793 printk(KERN_ERR "Unable to create ecryptfs kset\n"); 794 rc = -ENOMEM; 795 goto out; 796 } 797 rc = sysfs_create_group(ecryptfs_kobj, &attr_group); 798 if (rc) { 799 printk(KERN_ERR 800 "Unable to create ecryptfs version attributes\n"); 801 kobject_put(ecryptfs_kobj); 802 } 803 out: 804 return rc; 805 } 806 807 static void do_sysfs_unregistration(void) 808 { 809 sysfs_remove_group(ecryptfs_kobj, &attr_group); 810 kobject_put(ecryptfs_kobj); 811 } 812 813 static int __init ecryptfs_init(void) 814 { 815 int rc; 816 817 if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) { 818 rc = -EINVAL; 819 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is " 820 "larger than the host's page size, and so " 821 "eCryptfs cannot run on this system. The " 822 "default eCryptfs extent size is [%d] bytes; " 823 "the page size is [%d] bytes.\n", 824 ECRYPTFS_DEFAULT_EXTENT_SIZE, PAGE_CACHE_SIZE); 825 goto out; 826 } 827 rc = ecryptfs_init_kmem_caches(); 828 if (rc) { 829 printk(KERN_ERR 830 "Failed to allocate one or more kmem_cache objects\n"); 831 goto out; 832 } 833 rc = register_filesystem(&ecryptfs_fs_type); 834 if (rc) { 835 printk(KERN_ERR "Failed to register filesystem\n"); 836 goto out_free_kmem_caches; 837 } 838 rc = do_sysfs_registration(); 839 if (rc) { 840 printk(KERN_ERR "sysfs registration failed\n"); 841 goto out_unregister_filesystem; 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 occured 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 if (ecryptfs_verbosity > 0) 863 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values " 864 "will be written to the syslog!\n", ecryptfs_verbosity); 865 866 goto out; 867 out_release_messaging: 868 ecryptfs_release_messaging(); 869 out_destroy_kthread: 870 ecryptfs_destroy_kthread(); 871 out_do_sysfs_unregistration: 872 do_sysfs_unregistration(); 873 out_unregister_filesystem: 874 unregister_filesystem(&ecryptfs_fs_type); 875 out_free_kmem_caches: 876 ecryptfs_free_kmem_caches(); 877 out: 878 return rc; 879 } 880 881 static void __exit ecryptfs_exit(void) 882 { 883 int rc; 884 885 rc = ecryptfs_destroy_crypto(); 886 if (rc) 887 printk(KERN_ERR "Failure whilst attempting to destroy crypto; " 888 "rc = [%d]\n", rc); 889 ecryptfs_release_messaging(); 890 ecryptfs_destroy_kthread(); 891 do_sysfs_unregistration(); 892 unregister_filesystem(&ecryptfs_fs_type); 893 ecryptfs_free_kmem_caches(); 894 } 895 896 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>"); 897 MODULE_DESCRIPTION("eCryptfs"); 898 899 MODULE_LICENSE("GPL"); 900 901 module_init(ecryptfs_init) 902 module_exit(ecryptfs_exit) 903