1 /** 2 * eCryptfs: Linux filesystem encryption layer 3 * 4 * Copyright (C) 1997-2004 Erez Zadok 5 * Copyright (C) 2001-2004 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. Thompsion <mcthomps@us.ibm.com> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation; either version 2 of the 13 * License, or (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, but 16 * WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 23 * 02111-1307, USA. 24 */ 25 26 #include <linux/file.h> 27 #include <linux/vmalloc.h> 28 #include <linux/pagemap.h> 29 #include <linux/dcache.h> 30 #include <linux/namei.h> 31 #include <linux/mount.h> 32 #include <linux/crypto.h> 33 #include <linux/fs_stack.h> 34 #include <asm/unaligned.h> 35 #include "ecryptfs_kernel.h" 36 37 static struct dentry *lock_parent(struct dentry *dentry) 38 { 39 struct dentry *dir; 40 41 dir = dget_parent(dentry); 42 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT); 43 return dir; 44 } 45 46 static void unlock_dir(struct dentry *dir) 47 { 48 mutex_unlock(&dir->d_inode->i_mutex); 49 dput(dir); 50 } 51 52 /** 53 * ecryptfs_create_underlying_file 54 * @lower_dir_inode: inode of the parent in the lower fs of the new file 55 * @dentry: New file's dentry 56 * @mode: The mode of the new file 57 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount 58 * 59 * Creates the file in the lower file system. 60 * 61 * Returns zero on success; non-zero on error condition 62 */ 63 static int 64 ecryptfs_create_underlying_file(struct inode *lower_dir_inode, 65 struct dentry *dentry, int mode, 66 struct nameidata *nd) 67 { 68 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 69 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry); 70 struct dentry *dentry_save; 71 struct vfsmount *vfsmount_save; 72 int rc; 73 74 dentry_save = nd->path.dentry; 75 vfsmount_save = nd->path.mnt; 76 nd->path.dentry = lower_dentry; 77 nd->path.mnt = lower_mnt; 78 rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd); 79 nd->path.dentry = dentry_save; 80 nd->path.mnt = vfsmount_save; 81 return rc; 82 } 83 84 /** 85 * ecryptfs_do_create 86 * @directory_inode: inode of the new file's dentry's parent in ecryptfs 87 * @ecryptfs_dentry: New file's dentry in ecryptfs 88 * @mode: The mode of the new file 89 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount 90 * 91 * Creates the underlying file and the eCryptfs inode which will link to 92 * it. It will also update the eCryptfs directory inode to mimic the 93 * stat of the lower directory inode. 94 * 95 * Returns zero on success; non-zero on error condition 96 */ 97 static int 98 ecryptfs_do_create(struct inode *directory_inode, 99 struct dentry *ecryptfs_dentry, int mode, 100 struct nameidata *nd) 101 { 102 int rc; 103 struct dentry *lower_dentry; 104 struct dentry *lower_dir_dentry; 105 106 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); 107 lower_dir_dentry = lock_parent(lower_dentry); 108 if (IS_ERR(lower_dir_dentry)) { 109 ecryptfs_printk(KERN_ERR, "Error locking directory of " 110 "dentry\n"); 111 rc = PTR_ERR(lower_dir_dentry); 112 goto out; 113 } 114 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode, 115 ecryptfs_dentry, mode, nd); 116 if (rc) { 117 printk(KERN_ERR "%s: Failure to create dentry in lower fs; " 118 "rc = [%d]\n", __func__, rc); 119 goto out_lock; 120 } 121 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry, 122 directory_inode->i_sb, 0); 123 if (rc) { 124 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n"); 125 goto out_lock; 126 } 127 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode); 128 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode); 129 out_lock: 130 unlock_dir(lower_dir_dentry); 131 out: 132 return rc; 133 } 134 135 /** 136 * grow_file 137 * @ecryptfs_dentry: the eCryptfs dentry 138 * 139 * This is the code which will grow the file to its correct size. 140 */ 141 static int grow_file(struct dentry *ecryptfs_dentry) 142 { 143 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode; 144 struct file fake_file; 145 struct ecryptfs_file_info tmp_file_info; 146 char zero_virt[] = { 0x00 }; 147 int rc = 0; 148 149 memset(&fake_file, 0, sizeof(fake_file)); 150 fake_file.f_path.dentry = ecryptfs_dentry; 151 memset(&tmp_file_info, 0, sizeof(tmp_file_info)); 152 ecryptfs_set_file_private(&fake_file, &tmp_file_info); 153 ecryptfs_set_file_lower( 154 &fake_file, 155 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file); 156 rc = ecryptfs_write(&fake_file, zero_virt, 0, 1); 157 i_size_write(ecryptfs_inode, 0); 158 rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode); 159 ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |= 160 ECRYPTFS_NEW_FILE; 161 return rc; 162 } 163 164 /** 165 * ecryptfs_initialize_file 166 * 167 * Cause the file to be changed from a basic empty file to an ecryptfs 168 * file with a header and first data page. 169 * 170 * Returns zero on success 171 */ 172 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry) 173 { 174 struct ecryptfs_crypt_stat *crypt_stat = 175 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; 176 int rc = 0; 177 178 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { 179 ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); 180 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 181 goto out; 182 } 183 crypt_stat->flags |= ECRYPTFS_NEW_FILE; 184 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n"); 185 rc = ecryptfs_new_file_context(ecryptfs_dentry); 186 if (rc) { 187 ecryptfs_printk(KERN_ERR, "Error creating new file " 188 "context; rc = [%d]\n", rc); 189 goto out; 190 } 191 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) { 192 rc = ecryptfs_init_persistent_file(ecryptfs_dentry); 193 if (rc) { 194 printk(KERN_ERR "%s: Error attempting to initialize " 195 "the persistent file for the dentry with name " 196 "[%s]; rc = [%d]\n", __func__, 197 ecryptfs_dentry->d_name.name, rc); 198 goto out; 199 } 200 } 201 rc = ecryptfs_write_metadata(ecryptfs_dentry); 202 if (rc) { 203 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc); 204 goto out; 205 } 206 rc = grow_file(ecryptfs_dentry); 207 if (rc) 208 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc); 209 out: 210 return rc; 211 } 212 213 /** 214 * ecryptfs_create 215 * @dir: The inode of the directory in which to create the file. 216 * @dentry: The eCryptfs dentry 217 * @mode: The mode of the new file. 218 * @nd: nameidata 219 * 220 * Creates a new file. 221 * 222 * Returns zero on success; non-zero on error condition 223 */ 224 static int 225 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry, 226 int mode, struct nameidata *nd) 227 { 228 int rc; 229 230 /* ecryptfs_do_create() calls ecryptfs_interpose() */ 231 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd); 232 if (unlikely(rc)) { 233 ecryptfs_printk(KERN_WARNING, "Failed to create file in" 234 "lower filesystem\n"); 235 goto out; 236 } 237 /* At this point, a file exists on "disk"; we need to make sure 238 * that this on disk file is prepared to be an ecryptfs file */ 239 rc = ecryptfs_initialize_file(ecryptfs_dentry); 240 out: 241 return rc; 242 } 243 244 /** 245 * ecryptfs_lookup_and_interpose_lower - Perform a lookup 246 */ 247 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry, 248 struct dentry *lower_dentry, 249 struct inode *ecryptfs_dir_inode, 250 struct nameidata *ecryptfs_nd) 251 { 252 struct dentry *lower_dir_dentry; 253 struct vfsmount *lower_mnt; 254 struct inode *lower_inode; 255 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 256 struct ecryptfs_crypt_stat *crypt_stat; 257 char *page_virt = NULL; 258 u64 file_size; 259 int rc = 0; 260 261 lower_dir_dentry = lower_dentry->d_parent; 262 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt( 263 ecryptfs_dentry->d_parent)); 264 lower_inode = lower_dentry->d_inode; 265 fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode); 266 BUG_ON(!atomic_read(&lower_dentry->d_count)); 267 ecryptfs_set_dentry_private(ecryptfs_dentry, 268 kmem_cache_alloc(ecryptfs_dentry_info_cache, 269 GFP_KERNEL)); 270 if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) { 271 rc = -ENOMEM; 272 printk(KERN_ERR "%s: Out of memory whilst attempting " 273 "to allocate ecryptfs_dentry_info struct\n", 274 __func__); 275 goto out_dput; 276 } 277 ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry); 278 ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt); 279 if (!lower_dentry->d_inode) { 280 /* We want to add because we couldn't find in lower */ 281 d_add(ecryptfs_dentry, NULL); 282 goto out; 283 } 284 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry, 285 ecryptfs_dir_inode->i_sb, 1); 286 if (rc) { 287 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n", 288 __func__, rc); 289 goto out; 290 } 291 if (S_ISDIR(lower_inode->i_mode)) 292 goto out; 293 if (S_ISLNK(lower_inode->i_mode)) 294 goto out; 295 if (special_file(lower_inode->i_mode)) 296 goto out; 297 if (!ecryptfs_nd) 298 goto out; 299 /* Released in this function */ 300 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER); 301 if (!page_virt) { 302 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n", 303 __func__); 304 rc = -ENOMEM; 305 goto out; 306 } 307 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) { 308 rc = ecryptfs_init_persistent_file(ecryptfs_dentry); 309 if (rc) { 310 printk(KERN_ERR "%s: Error attempting to initialize " 311 "the persistent file for the dentry with name " 312 "[%s]; rc = [%d]\n", __func__, 313 ecryptfs_dentry->d_name.name, rc); 314 goto out_free_kmem; 315 } 316 } 317 crypt_stat = &ecryptfs_inode_to_private( 318 ecryptfs_dentry->d_inode)->crypt_stat; 319 /* TODO: lock for crypt_stat comparison */ 320 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) 321 ecryptfs_set_default_sizes(crypt_stat); 322 rc = ecryptfs_read_and_validate_header_region(page_virt, 323 ecryptfs_dentry->d_inode); 324 if (rc) { 325 rc = ecryptfs_read_and_validate_xattr_region(page_virt, 326 ecryptfs_dentry); 327 if (rc) { 328 rc = 0; 329 goto out_free_kmem; 330 } 331 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; 332 } 333 mount_crypt_stat = &ecryptfs_superblock_to_private( 334 ecryptfs_dentry->d_sb)->mount_crypt_stat; 335 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { 336 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) 337 file_size = (crypt_stat->num_header_bytes_at_front 338 + i_size_read(lower_dentry->d_inode)); 339 else 340 file_size = i_size_read(lower_dentry->d_inode); 341 } else { 342 file_size = get_unaligned_be64(page_virt); 343 } 344 i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size); 345 out_free_kmem: 346 kmem_cache_free(ecryptfs_header_cache_2, page_virt); 347 goto out; 348 out_dput: 349 dput(lower_dentry); 350 d_drop(ecryptfs_dentry); 351 out: 352 return rc; 353 } 354 355 /** 356 * ecryptfs_lookup 357 * @ecryptfs_dir_inode: The eCryptfs directory inode 358 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up 359 * @ecryptfs_nd: nameidata; may be NULL 360 * 361 * Find a file on disk. If the file does not exist, then we'll add it to the 362 * dentry cache and continue on to read it from the disk. 363 */ 364 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode, 365 struct dentry *ecryptfs_dentry, 366 struct nameidata *ecryptfs_nd) 367 { 368 char *encrypted_and_encoded_name = NULL; 369 size_t encrypted_and_encoded_name_size; 370 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 371 struct dentry *lower_dir_dentry, *lower_dentry; 372 int rc = 0; 373 374 ecryptfs_dentry->d_op = &ecryptfs_dops; 375 if ((ecryptfs_dentry->d_name.len == 1 376 && !strcmp(ecryptfs_dentry->d_name.name, ".")) 377 || (ecryptfs_dentry->d_name.len == 2 378 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) { 379 goto out_d_drop; 380 } 381 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent); 382 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name, 383 lower_dir_dentry, 384 ecryptfs_dentry->d_name.len); 385 if (IS_ERR(lower_dentry)) { 386 rc = PTR_ERR(lower_dentry); 387 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on " 388 "lower_dentry = [%s]\n", __func__, rc, 389 ecryptfs_dentry->d_name.name); 390 goto out_d_drop; 391 } 392 if (lower_dentry->d_inode) 393 goto lookup_and_interpose; 394 mount_crypt_stat = &ecryptfs_superblock_to_private( 395 ecryptfs_dentry->d_sb)->mount_crypt_stat; 396 if (!(mount_crypt_stat 397 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) 398 goto lookup_and_interpose; 399 dput(lower_dentry); 400 rc = ecryptfs_encrypt_and_encode_filename( 401 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size, 402 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name, 403 ecryptfs_dentry->d_name.len); 404 if (rc) { 405 printk(KERN_ERR "%s: Error attempting to encrypt and encode " 406 "filename; rc = [%d]\n", __func__, rc); 407 goto out_d_drop; 408 } 409 lower_dentry = lookup_one_len(encrypted_and_encoded_name, 410 lower_dir_dentry, 411 encrypted_and_encoded_name_size - 1); 412 if (IS_ERR(lower_dentry)) { 413 rc = PTR_ERR(lower_dentry); 414 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on " 415 "lower_dentry = [%s]\n", __func__, rc, 416 encrypted_and_encoded_name); 417 goto out_d_drop; 418 } 419 lookup_and_interpose: 420 rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry, 421 ecryptfs_dir_inode, 422 ecryptfs_nd); 423 goto out; 424 out_d_drop: 425 d_drop(ecryptfs_dentry); 426 out: 427 kfree(encrypted_and_encoded_name); 428 return ERR_PTR(rc); 429 } 430 431 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir, 432 struct dentry *new_dentry) 433 { 434 struct dentry *lower_old_dentry; 435 struct dentry *lower_new_dentry; 436 struct dentry *lower_dir_dentry; 437 u64 file_size_save; 438 int rc; 439 440 file_size_save = i_size_read(old_dentry->d_inode); 441 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 442 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 443 dget(lower_old_dentry); 444 dget(lower_new_dentry); 445 lower_dir_dentry = lock_parent(lower_new_dentry); 446 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode, 447 lower_new_dentry); 448 if (rc || !lower_new_dentry->d_inode) 449 goto out_lock; 450 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0); 451 if (rc) 452 goto out_lock; 453 fsstack_copy_attr_times(dir, lower_new_dentry->d_inode); 454 fsstack_copy_inode_size(dir, lower_new_dentry->d_inode); 455 old_dentry->d_inode->i_nlink = 456 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink; 457 i_size_write(new_dentry->d_inode, file_size_save); 458 out_lock: 459 unlock_dir(lower_dir_dentry); 460 dput(lower_new_dentry); 461 dput(lower_old_dentry); 462 d_drop(lower_old_dentry); 463 d_drop(new_dentry); 464 d_drop(old_dentry); 465 return rc; 466 } 467 468 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) 469 { 470 int rc = 0; 471 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 472 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); 473 struct dentry *lower_dir_dentry; 474 475 lower_dir_dentry = lock_parent(lower_dentry); 476 rc = vfs_unlink(lower_dir_inode, lower_dentry); 477 if (rc) { 478 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); 479 goto out_unlock; 480 } 481 fsstack_copy_attr_times(dir, lower_dir_inode); 482 dentry->d_inode->i_nlink = 483 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink; 484 dentry->d_inode->i_ctime = dir->i_ctime; 485 d_drop(dentry); 486 out_unlock: 487 unlock_dir(lower_dir_dentry); 488 return rc; 489 } 490 491 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry, 492 const char *symname) 493 { 494 int rc; 495 struct dentry *lower_dentry; 496 struct dentry *lower_dir_dentry; 497 char *encoded_symname; 498 size_t encoded_symlen; 499 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 500 501 lower_dentry = ecryptfs_dentry_to_lower(dentry); 502 dget(lower_dentry); 503 lower_dir_dentry = lock_parent(lower_dentry); 504 mount_crypt_stat = &ecryptfs_superblock_to_private( 505 dir->i_sb)->mount_crypt_stat; 506 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname, 507 &encoded_symlen, 508 NULL, 509 mount_crypt_stat, symname, 510 strlen(symname)); 511 if (rc) 512 goto out_lock; 513 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry, 514 encoded_symname); 515 kfree(encoded_symname); 516 if (rc || !lower_dentry->d_inode) 517 goto out_lock; 518 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 519 if (rc) 520 goto out_lock; 521 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 522 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 523 out_lock: 524 unlock_dir(lower_dir_dentry); 525 dput(lower_dentry); 526 if (!dentry->d_inode) 527 d_drop(dentry); 528 return rc; 529 } 530 531 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 532 { 533 int rc; 534 struct dentry *lower_dentry; 535 struct dentry *lower_dir_dentry; 536 537 lower_dentry = ecryptfs_dentry_to_lower(dentry); 538 lower_dir_dentry = lock_parent(lower_dentry); 539 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode); 540 if (rc || !lower_dentry->d_inode) 541 goto out; 542 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 543 if (rc) 544 goto out; 545 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 546 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 547 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 548 out: 549 unlock_dir(lower_dir_dentry); 550 if (!dentry->d_inode) 551 d_drop(dentry); 552 return rc; 553 } 554 555 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) 556 { 557 struct dentry *lower_dentry; 558 struct dentry *lower_dir_dentry; 559 int rc; 560 561 lower_dentry = ecryptfs_dentry_to_lower(dentry); 562 dget(dentry); 563 lower_dir_dentry = lock_parent(lower_dentry); 564 dget(lower_dentry); 565 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry); 566 dput(lower_dentry); 567 if (!rc) 568 d_delete(lower_dentry); 569 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 570 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 571 unlock_dir(lower_dir_dentry); 572 if (!rc) 573 d_drop(dentry); 574 dput(dentry); 575 return rc; 576 } 577 578 static int 579 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 580 { 581 int rc; 582 struct dentry *lower_dentry; 583 struct dentry *lower_dir_dentry; 584 585 lower_dentry = ecryptfs_dentry_to_lower(dentry); 586 lower_dir_dentry = lock_parent(lower_dentry); 587 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); 588 if (rc || !lower_dentry->d_inode) 589 goto out; 590 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 591 if (rc) 592 goto out; 593 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 594 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 595 out: 596 unlock_dir(lower_dir_dentry); 597 if (!dentry->d_inode) 598 d_drop(dentry); 599 return rc; 600 } 601 602 static int 603 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, 604 struct inode *new_dir, struct dentry *new_dentry) 605 { 606 int rc; 607 struct dentry *lower_old_dentry; 608 struct dentry *lower_new_dentry; 609 struct dentry *lower_old_dir_dentry; 610 struct dentry *lower_new_dir_dentry; 611 612 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 613 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 614 dget(lower_old_dentry); 615 dget(lower_new_dentry); 616 lower_old_dir_dentry = dget_parent(lower_old_dentry); 617 lower_new_dir_dentry = dget_parent(lower_new_dentry); 618 lock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 619 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry, 620 lower_new_dir_dentry->d_inode, lower_new_dentry); 621 if (rc) 622 goto out_lock; 623 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL); 624 if (new_dir != old_dir) 625 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL); 626 out_lock: 627 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 628 dput(lower_new_dentry->d_parent); 629 dput(lower_old_dentry->d_parent); 630 dput(lower_new_dentry); 631 dput(lower_old_dentry); 632 return rc; 633 } 634 635 static int 636 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz) 637 { 638 char *lower_buf; 639 struct dentry *lower_dentry; 640 struct ecryptfs_crypt_stat *crypt_stat; 641 char *plaintext_name; 642 size_t plaintext_name_size; 643 mm_segment_t old_fs; 644 int rc; 645 646 lower_dentry = ecryptfs_dentry_to_lower(dentry); 647 if (!lower_dentry->d_inode->i_op->readlink) { 648 rc = -EINVAL; 649 goto out; 650 } 651 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 652 /* Released in this function */ 653 lower_buf = kmalloc(bufsiz, GFP_KERNEL); 654 if (lower_buf == NULL) { 655 printk(KERN_ERR "%s: Out of memory whilst attempting to " 656 "kmalloc [%d] bytes\n", __func__, bufsiz); 657 rc = -ENOMEM; 658 goto out; 659 } 660 old_fs = get_fs(); 661 set_fs(get_ds()); 662 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry, 663 (char __user *)lower_buf, 664 bufsiz); 665 set_fs(old_fs); 666 if (rc >= 0) { 667 rc = ecryptfs_decode_and_decrypt_filename(&plaintext_name, 668 &plaintext_name_size, 669 dentry, lower_buf, 670 rc); 671 if (rc) { 672 printk(KERN_ERR "%s: Error attempting to decode and " 673 "decrypt filename; rc = [%d]\n", __func__, 674 rc); 675 goto out_free_lower_buf; 676 } 677 rc = copy_to_user(buf, plaintext_name, plaintext_name_size); 678 if (rc) 679 rc = -EFAULT; 680 else 681 rc = plaintext_name_size; 682 kfree(plaintext_name); 683 fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode); 684 } 685 out_free_lower_buf: 686 kfree(lower_buf); 687 out: 688 return rc; 689 } 690 691 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd) 692 { 693 char *buf; 694 int len = PAGE_SIZE, rc; 695 mm_segment_t old_fs; 696 697 /* Released in ecryptfs_put_link(); only release here on error */ 698 buf = kmalloc(len, GFP_KERNEL); 699 if (!buf) { 700 rc = -ENOMEM; 701 goto out; 702 } 703 old_fs = get_fs(); 704 set_fs(get_ds()); 705 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len); 706 set_fs(old_fs); 707 if (rc < 0) 708 goto out_free; 709 else 710 buf[rc] = '\0'; 711 rc = 0; 712 nd_set_link(nd, buf); 713 goto out; 714 out_free: 715 kfree(buf); 716 out: 717 return ERR_PTR(rc); 718 } 719 720 static void 721 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr) 722 { 723 /* Free the char* */ 724 kfree(nd_get_link(nd)); 725 } 726 727 /** 728 * upper_size_to_lower_size 729 * @crypt_stat: Crypt_stat associated with file 730 * @upper_size: Size of the upper file 731 * 732 * Calculate the required size of the lower file based on the 733 * specified size of the upper file. This calculation is based on the 734 * number of headers in the underlying file and the extent size. 735 * 736 * Returns Calculated size of the lower file. 737 */ 738 static loff_t 739 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, 740 loff_t upper_size) 741 { 742 loff_t lower_size; 743 744 lower_size = crypt_stat->num_header_bytes_at_front; 745 if (upper_size != 0) { 746 loff_t num_extents; 747 748 num_extents = upper_size >> crypt_stat->extent_shift; 749 if (upper_size & ~crypt_stat->extent_mask) 750 num_extents++; 751 lower_size += (num_extents * crypt_stat->extent_size); 752 } 753 return lower_size; 754 } 755 756 /** 757 * ecryptfs_truncate 758 * @dentry: The ecryptfs layer dentry 759 * @new_length: The length to expand the file to 760 * 761 * Function to handle truncations modifying the size of the file. Note 762 * that the file sizes are interpolated. When expanding, we are simply 763 * writing strings of 0's out. When truncating, we need to modify the 764 * underlying file size according to the page index interpolations. 765 * 766 * Returns zero on success; non-zero otherwise 767 */ 768 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) 769 { 770 int rc = 0; 771 struct inode *inode = dentry->d_inode; 772 struct dentry *lower_dentry; 773 struct file fake_ecryptfs_file; 774 struct ecryptfs_crypt_stat *crypt_stat; 775 loff_t i_size = i_size_read(inode); 776 loff_t lower_size_before_truncate; 777 loff_t lower_size_after_truncate; 778 779 if (unlikely((new_length == i_size))) 780 goto out; 781 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 782 /* Set up a fake ecryptfs file, this is used to interface with 783 * the file in the underlying filesystem so that the 784 * truncation has an effect there as well. */ 785 memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file)); 786 fake_ecryptfs_file.f_path.dentry = dentry; 787 /* Released at out_free: label */ 788 ecryptfs_set_file_private(&fake_ecryptfs_file, 789 kmem_cache_alloc(ecryptfs_file_info_cache, 790 GFP_KERNEL)); 791 if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) { 792 rc = -ENOMEM; 793 goto out; 794 } 795 lower_dentry = ecryptfs_dentry_to_lower(dentry); 796 ecryptfs_set_file_lower( 797 &fake_ecryptfs_file, 798 ecryptfs_inode_to_private(dentry->d_inode)->lower_file); 799 /* Switch on growing or shrinking file */ 800 if (new_length > i_size) { 801 char zero[] = { 0x00 }; 802 803 /* Write a single 0 at the last position of the file; 804 * this triggers code that will fill in 0's throughout 805 * the intermediate portion of the previous end of the 806 * file and the new and of the file */ 807 rc = ecryptfs_write(&fake_ecryptfs_file, zero, 808 (new_length - 1), 1); 809 } else { /* new_length < i_size_read(inode) */ 810 /* We're chopping off all the pages down do the page 811 * in which new_length is located. Fill in the end of 812 * that page from (new_length & ~PAGE_CACHE_MASK) to 813 * PAGE_CACHE_SIZE with zeros. */ 814 size_t num_zeros = (PAGE_CACHE_SIZE 815 - (new_length & ~PAGE_CACHE_MASK)); 816 817 if (num_zeros) { 818 char *zeros_virt; 819 820 zeros_virt = kzalloc(num_zeros, GFP_KERNEL); 821 if (!zeros_virt) { 822 rc = -ENOMEM; 823 goto out_free; 824 } 825 rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt, 826 new_length, num_zeros); 827 kfree(zeros_virt); 828 if (rc) { 829 printk(KERN_ERR "Error attempting to zero out " 830 "the remainder of the end page on " 831 "reducing truncate; rc = [%d]\n", rc); 832 goto out_free; 833 } 834 } 835 vmtruncate(inode, new_length); 836 rc = ecryptfs_write_inode_size_to_metadata(inode); 837 if (rc) { 838 printk(KERN_ERR "Problem with " 839 "ecryptfs_write_inode_size_to_metadata; " 840 "rc = [%d]\n", rc); 841 goto out_free; 842 } 843 /* We are reducing the size of the ecryptfs file, and need to 844 * know if we need to reduce the size of the lower file. */ 845 lower_size_before_truncate = 846 upper_size_to_lower_size(crypt_stat, i_size); 847 lower_size_after_truncate = 848 upper_size_to_lower_size(crypt_stat, new_length); 849 if (lower_size_after_truncate < lower_size_before_truncate) 850 vmtruncate(lower_dentry->d_inode, 851 lower_size_after_truncate); 852 } 853 out_free: 854 if (ecryptfs_file_to_private(&fake_ecryptfs_file)) 855 kmem_cache_free(ecryptfs_file_info_cache, 856 ecryptfs_file_to_private(&fake_ecryptfs_file)); 857 out: 858 return rc; 859 } 860 861 static int 862 ecryptfs_permission(struct inode *inode, int mask) 863 { 864 return inode_permission(ecryptfs_inode_to_lower(inode), mask); 865 } 866 867 /** 868 * ecryptfs_setattr 869 * @dentry: dentry handle to the inode to modify 870 * @ia: Structure with flags of what to change and values 871 * 872 * Updates the metadata of an inode. If the update is to the size 873 * i.e. truncation, then ecryptfs_truncate will handle the size modification 874 * of both the ecryptfs inode and the lower inode. 875 * 876 * All other metadata changes will be passed right to the lower filesystem, 877 * and we will just update our inode to look like the lower. 878 */ 879 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) 880 { 881 int rc = 0; 882 struct dentry *lower_dentry; 883 struct inode *inode; 884 struct inode *lower_inode; 885 struct ecryptfs_crypt_stat *crypt_stat; 886 887 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 888 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) 889 ecryptfs_init_crypt_stat(crypt_stat); 890 inode = dentry->d_inode; 891 lower_inode = ecryptfs_inode_to_lower(inode); 892 lower_dentry = ecryptfs_dentry_to_lower(dentry); 893 mutex_lock(&crypt_stat->cs_mutex); 894 if (S_ISDIR(dentry->d_inode->i_mode)) 895 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 896 else if (S_ISREG(dentry->d_inode->i_mode) 897 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) 898 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) { 899 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 900 901 mount_crypt_stat = &ecryptfs_superblock_to_private( 902 dentry->d_sb)->mount_crypt_stat; 903 rc = ecryptfs_read_metadata(dentry); 904 if (rc) { 905 if (!(mount_crypt_stat->flags 906 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { 907 rc = -EIO; 908 printk(KERN_WARNING "Either the lower file " 909 "is not in a valid eCryptfs format, " 910 "or the key could not be retrieved. " 911 "Plaintext passthrough mode is not " 912 "enabled; returning -EIO\n"); 913 mutex_unlock(&crypt_stat->cs_mutex); 914 goto out; 915 } 916 rc = 0; 917 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 918 mutex_unlock(&crypt_stat->cs_mutex); 919 goto out; 920 } 921 } 922 mutex_unlock(&crypt_stat->cs_mutex); 923 if (ia->ia_valid & ATTR_SIZE) { 924 ecryptfs_printk(KERN_DEBUG, 925 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n", 926 ia->ia_valid, ATTR_SIZE); 927 rc = ecryptfs_truncate(dentry, ia->ia_size); 928 /* ecryptfs_truncate handles resizing of the lower file */ 929 ia->ia_valid &= ~ATTR_SIZE; 930 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n", 931 ia->ia_valid); 932 if (rc < 0) 933 goto out; 934 } 935 936 /* 937 * mode change is for clearing setuid/setgid bits. Allow lower fs 938 * to interpret this in its own way. 939 */ 940 if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) 941 ia->ia_valid &= ~ATTR_MODE; 942 943 mutex_lock(&lower_dentry->d_inode->i_mutex); 944 rc = notify_change(lower_dentry, ia); 945 mutex_unlock(&lower_dentry->d_inode->i_mutex); 946 out: 947 fsstack_copy_attr_all(inode, lower_inode, NULL); 948 return rc; 949 } 950 951 int 952 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value, 953 size_t size, int flags) 954 { 955 int rc = 0; 956 struct dentry *lower_dentry; 957 958 lower_dentry = ecryptfs_dentry_to_lower(dentry); 959 if (!lower_dentry->d_inode->i_op->setxattr) { 960 rc = -ENOSYS; 961 goto out; 962 } 963 mutex_lock(&lower_dentry->d_inode->i_mutex); 964 rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value, 965 size, flags); 966 mutex_unlock(&lower_dentry->d_inode->i_mutex); 967 out: 968 return rc; 969 } 970 971 ssize_t 972 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name, 973 void *value, size_t size) 974 { 975 int rc = 0; 976 977 if (!lower_dentry->d_inode->i_op->getxattr) { 978 rc = -ENOSYS; 979 goto out; 980 } 981 mutex_lock(&lower_dentry->d_inode->i_mutex); 982 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value, 983 size); 984 mutex_unlock(&lower_dentry->d_inode->i_mutex); 985 out: 986 return rc; 987 } 988 989 static ssize_t 990 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value, 991 size_t size) 992 { 993 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name, 994 value, size); 995 } 996 997 static ssize_t 998 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size) 999 { 1000 int rc = 0; 1001 struct dentry *lower_dentry; 1002 1003 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1004 if (!lower_dentry->d_inode->i_op->listxattr) { 1005 rc = -ENOSYS; 1006 goto out; 1007 } 1008 mutex_lock(&lower_dentry->d_inode->i_mutex); 1009 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size); 1010 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1011 out: 1012 return rc; 1013 } 1014 1015 static int ecryptfs_removexattr(struct dentry *dentry, const char *name) 1016 { 1017 int rc = 0; 1018 struct dentry *lower_dentry; 1019 1020 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1021 if (!lower_dentry->d_inode->i_op->removexattr) { 1022 rc = -ENOSYS; 1023 goto out; 1024 } 1025 mutex_lock(&lower_dentry->d_inode->i_mutex); 1026 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name); 1027 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1028 out: 1029 return rc; 1030 } 1031 1032 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode) 1033 { 1034 if ((ecryptfs_inode_to_lower(inode) 1035 == (struct inode *)candidate_lower_inode)) 1036 return 1; 1037 else 1038 return 0; 1039 } 1040 1041 int ecryptfs_inode_set(struct inode *inode, void *lower_inode) 1042 { 1043 ecryptfs_init_inode(inode, (struct inode *)lower_inode); 1044 return 0; 1045 } 1046 1047 const struct inode_operations ecryptfs_symlink_iops = { 1048 .readlink = ecryptfs_readlink, 1049 .follow_link = ecryptfs_follow_link, 1050 .put_link = ecryptfs_put_link, 1051 .permission = ecryptfs_permission, 1052 .setattr = ecryptfs_setattr, 1053 .setxattr = ecryptfs_setxattr, 1054 .getxattr = ecryptfs_getxattr, 1055 .listxattr = ecryptfs_listxattr, 1056 .removexattr = ecryptfs_removexattr 1057 }; 1058 1059 const struct inode_operations ecryptfs_dir_iops = { 1060 .create = ecryptfs_create, 1061 .lookup = ecryptfs_lookup, 1062 .link = ecryptfs_link, 1063 .unlink = ecryptfs_unlink, 1064 .symlink = ecryptfs_symlink, 1065 .mkdir = ecryptfs_mkdir, 1066 .rmdir = ecryptfs_rmdir, 1067 .mknod = ecryptfs_mknod, 1068 .rename = ecryptfs_rename, 1069 .permission = ecryptfs_permission, 1070 .setattr = ecryptfs_setattr, 1071 .setxattr = ecryptfs_setxattr, 1072 .getxattr = ecryptfs_getxattr, 1073 .listxattr = ecryptfs_listxattr, 1074 .removexattr = ecryptfs_removexattr 1075 }; 1076 1077 const struct inode_operations ecryptfs_main_iops = { 1078 .permission = ecryptfs_permission, 1079 .setattr = ecryptfs_setattr, 1080 .setxattr = ecryptfs_setxattr, 1081 .getxattr = ecryptfs_getxattr, 1082 .listxattr = ecryptfs_listxattr, 1083 .removexattr = ecryptfs_removexattr 1084 }; 1085