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/fs_stack.h> 33 #include <linux/slab.h> 34 #include <linux/xattr.h> 35 #include <asm/unaligned.h> 36 #include "ecryptfs_kernel.h" 37 38 static struct dentry *lock_parent(struct dentry *dentry) 39 { 40 struct dentry *dir; 41 42 dir = dget_parent(dentry); 43 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT); 44 return dir; 45 } 46 47 static void unlock_dir(struct dentry *dir) 48 { 49 inode_unlock(d_inode(dir)); 50 dput(dir); 51 } 52 53 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode) 54 { 55 return ecryptfs_inode_to_lower(inode) == lower_inode; 56 } 57 58 static int ecryptfs_inode_set(struct inode *inode, void *opaque) 59 { 60 struct inode *lower_inode = opaque; 61 62 ecryptfs_set_inode_lower(inode, lower_inode); 63 fsstack_copy_attr_all(inode, lower_inode); 64 /* i_size will be overwritten for encrypted regular files */ 65 fsstack_copy_inode_size(inode, lower_inode); 66 inode->i_ino = lower_inode->i_ino; 67 inode->i_version++; 68 inode->i_mapping->a_ops = &ecryptfs_aops; 69 70 if (S_ISLNK(inode->i_mode)) 71 inode->i_op = &ecryptfs_symlink_iops; 72 else if (S_ISDIR(inode->i_mode)) 73 inode->i_op = &ecryptfs_dir_iops; 74 else 75 inode->i_op = &ecryptfs_main_iops; 76 77 if (S_ISDIR(inode->i_mode)) 78 inode->i_fop = &ecryptfs_dir_fops; 79 else if (special_file(inode->i_mode)) 80 init_special_inode(inode, inode->i_mode, inode->i_rdev); 81 else 82 inode->i_fop = &ecryptfs_main_fops; 83 84 return 0; 85 } 86 87 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode, 88 struct super_block *sb) 89 { 90 struct inode *inode; 91 92 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) 93 return ERR_PTR(-EXDEV); 94 if (!igrab(lower_inode)) 95 return ERR_PTR(-ESTALE); 96 inode = iget5_locked(sb, (unsigned long)lower_inode, 97 ecryptfs_inode_test, ecryptfs_inode_set, 98 lower_inode); 99 if (!inode) { 100 iput(lower_inode); 101 return ERR_PTR(-EACCES); 102 } 103 if (!(inode->i_state & I_NEW)) 104 iput(lower_inode); 105 106 return inode; 107 } 108 109 struct inode *ecryptfs_get_inode(struct inode *lower_inode, 110 struct super_block *sb) 111 { 112 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb); 113 114 if (!IS_ERR(inode) && (inode->i_state & I_NEW)) 115 unlock_new_inode(inode); 116 117 return inode; 118 } 119 120 /** 121 * ecryptfs_interpose 122 * @lower_dentry: Existing dentry in the lower filesystem 123 * @dentry: ecryptfs' dentry 124 * @sb: ecryptfs's super_block 125 * 126 * Interposes upper and lower dentries. 127 * 128 * Returns zero on success; non-zero otherwise 129 */ 130 static int ecryptfs_interpose(struct dentry *lower_dentry, 131 struct dentry *dentry, struct super_block *sb) 132 { 133 struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb); 134 135 if (IS_ERR(inode)) 136 return PTR_ERR(inode); 137 d_instantiate(dentry, inode); 138 139 return 0; 140 } 141 142 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry, 143 struct inode *inode) 144 { 145 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 146 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); 147 struct dentry *lower_dir_dentry; 148 int rc; 149 150 dget(lower_dentry); 151 lower_dir_dentry = lock_parent(lower_dentry); 152 rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL); 153 if (rc) { 154 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); 155 goto out_unlock; 156 } 157 fsstack_copy_attr_times(dir, lower_dir_inode); 158 set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink); 159 inode->i_ctime = dir->i_ctime; 160 d_drop(dentry); 161 out_unlock: 162 unlock_dir(lower_dir_dentry); 163 dput(lower_dentry); 164 return rc; 165 } 166 167 /** 168 * ecryptfs_do_create 169 * @directory_inode: inode of the new file's dentry's parent in ecryptfs 170 * @ecryptfs_dentry: New file's dentry in ecryptfs 171 * @mode: The mode of the new file 172 * 173 * Creates the underlying file and the eCryptfs inode which will link to 174 * it. It will also update the eCryptfs directory inode to mimic the 175 * stat of the lower directory inode. 176 * 177 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition 178 */ 179 static struct inode * 180 ecryptfs_do_create(struct inode *directory_inode, 181 struct dentry *ecryptfs_dentry, umode_t mode) 182 { 183 int rc; 184 struct dentry *lower_dentry; 185 struct dentry *lower_dir_dentry; 186 struct inode *inode; 187 188 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); 189 lower_dir_dentry = lock_parent(lower_dentry); 190 rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true); 191 if (rc) { 192 printk(KERN_ERR "%s: Failure to create dentry in lower fs; " 193 "rc = [%d]\n", __func__, rc); 194 inode = ERR_PTR(rc); 195 goto out_lock; 196 } 197 inode = __ecryptfs_get_inode(d_inode(lower_dentry), 198 directory_inode->i_sb); 199 if (IS_ERR(inode)) { 200 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL); 201 goto out_lock; 202 } 203 fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry)); 204 fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry)); 205 out_lock: 206 unlock_dir(lower_dir_dentry); 207 return inode; 208 } 209 210 /** 211 * ecryptfs_initialize_file 212 * 213 * Cause the file to be changed from a basic empty file to an ecryptfs 214 * file with a header and first data page. 215 * 216 * Returns zero on success 217 */ 218 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry, 219 struct inode *ecryptfs_inode) 220 { 221 struct ecryptfs_crypt_stat *crypt_stat = 222 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; 223 int rc = 0; 224 225 if (S_ISDIR(ecryptfs_inode->i_mode)) { 226 ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); 227 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 228 goto out; 229 } 230 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n"); 231 rc = ecryptfs_new_file_context(ecryptfs_inode); 232 if (rc) { 233 ecryptfs_printk(KERN_ERR, "Error creating new file " 234 "context; rc = [%d]\n", rc); 235 goto out; 236 } 237 rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode); 238 if (rc) { 239 printk(KERN_ERR "%s: Error attempting to initialize " 240 "the lower file for the dentry with name " 241 "[%pd]; rc = [%d]\n", __func__, 242 ecryptfs_dentry, rc); 243 goto out; 244 } 245 rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode); 246 if (rc) 247 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc); 248 ecryptfs_put_lower_file(ecryptfs_inode); 249 out: 250 return rc; 251 } 252 253 /** 254 * ecryptfs_create 255 * @dir: The inode of the directory in which to create the file. 256 * @dentry: The eCryptfs dentry 257 * @mode: The mode of the new file. 258 * 259 * Creates a new file. 260 * 261 * Returns zero on success; non-zero on error condition 262 */ 263 static int 264 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry, 265 umode_t mode, bool excl) 266 { 267 struct inode *ecryptfs_inode; 268 int rc; 269 270 ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry, 271 mode); 272 if (IS_ERR(ecryptfs_inode)) { 273 ecryptfs_printk(KERN_WARNING, "Failed to create file in" 274 "lower filesystem\n"); 275 rc = PTR_ERR(ecryptfs_inode); 276 goto out; 277 } 278 /* At this point, a file exists on "disk"; we need to make sure 279 * that this on disk file is prepared to be an ecryptfs file */ 280 rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode); 281 if (rc) { 282 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry, 283 ecryptfs_inode); 284 iget_failed(ecryptfs_inode); 285 goto out; 286 } 287 unlock_new_inode(ecryptfs_inode); 288 d_instantiate(ecryptfs_dentry, ecryptfs_inode); 289 out: 290 return rc; 291 } 292 293 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode) 294 { 295 struct ecryptfs_crypt_stat *crypt_stat; 296 int rc; 297 298 rc = ecryptfs_get_lower_file(dentry, inode); 299 if (rc) { 300 printk(KERN_ERR "%s: Error attempting to initialize " 301 "the lower file for the dentry with name " 302 "[%pd]; rc = [%d]\n", __func__, 303 dentry, rc); 304 return rc; 305 } 306 307 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; 308 /* TODO: lock for crypt_stat comparison */ 309 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) 310 ecryptfs_set_default_sizes(crypt_stat); 311 312 rc = ecryptfs_read_and_validate_header_region(inode); 313 ecryptfs_put_lower_file(inode); 314 if (rc) { 315 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode); 316 if (!rc) 317 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; 318 } 319 320 /* Must return 0 to allow non-eCryptfs files to be looked up, too */ 321 return 0; 322 } 323 324 /** 325 * ecryptfs_lookup_interpose - Dentry interposition for a lookup 326 */ 327 static int ecryptfs_lookup_interpose(struct dentry *dentry, 328 struct dentry *lower_dentry, 329 struct inode *dir_inode) 330 { 331 struct inode *inode, *lower_inode = d_inode(lower_dentry); 332 struct ecryptfs_dentry_info *dentry_info; 333 struct vfsmount *lower_mnt; 334 int rc = 0; 335 336 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL); 337 if (!dentry_info) { 338 printk(KERN_ERR "%s: Out of memory whilst attempting " 339 "to allocate ecryptfs_dentry_info struct\n", 340 __func__); 341 dput(lower_dentry); 342 return -ENOMEM; 343 } 344 345 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent)); 346 fsstack_copy_attr_atime(dir_inode, d_inode(lower_dentry->d_parent)); 347 BUG_ON(!d_count(lower_dentry)); 348 349 ecryptfs_set_dentry_private(dentry, dentry_info); 350 dentry_info->lower_path.mnt = lower_mnt; 351 dentry_info->lower_path.dentry = lower_dentry; 352 353 if (d_really_is_negative(lower_dentry)) { 354 /* We want to add because we couldn't find in lower */ 355 d_add(dentry, NULL); 356 return 0; 357 } 358 inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb); 359 if (IS_ERR(inode)) { 360 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n", 361 __func__, PTR_ERR(inode)); 362 return PTR_ERR(inode); 363 } 364 if (S_ISREG(inode->i_mode)) { 365 rc = ecryptfs_i_size_read(dentry, inode); 366 if (rc) { 367 make_bad_inode(inode); 368 return rc; 369 } 370 } 371 372 if (inode->i_state & I_NEW) 373 unlock_new_inode(inode); 374 d_add(dentry, inode); 375 376 return rc; 377 } 378 379 /** 380 * ecryptfs_lookup 381 * @ecryptfs_dir_inode: The eCryptfs directory inode 382 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up 383 * @flags: lookup flags 384 * 385 * Find a file on disk. If the file does not exist, then we'll add it to the 386 * dentry cache and continue on to read it from the disk. 387 */ 388 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode, 389 struct dentry *ecryptfs_dentry, 390 unsigned int flags) 391 { 392 char *encrypted_and_encoded_name = NULL; 393 size_t encrypted_and_encoded_name_size; 394 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 395 struct dentry *lower_dir_dentry, *lower_dentry; 396 int rc = 0; 397 398 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent); 399 lower_dentry = lookup_one_len_unlocked(ecryptfs_dentry->d_name.name, 400 lower_dir_dentry, 401 ecryptfs_dentry->d_name.len); 402 if (IS_ERR(lower_dentry)) { 403 rc = PTR_ERR(lower_dentry); 404 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned " 405 "[%d] on lower_dentry = [%pd]\n", __func__, rc, 406 ecryptfs_dentry); 407 goto out; 408 } 409 if (d_really_is_positive(lower_dentry)) 410 goto interpose; 411 mount_crypt_stat = &ecryptfs_superblock_to_private( 412 ecryptfs_dentry->d_sb)->mount_crypt_stat; 413 if (!(mount_crypt_stat 414 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) 415 goto interpose; 416 dput(lower_dentry); 417 rc = ecryptfs_encrypt_and_encode_filename( 418 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size, 419 mount_crypt_stat, ecryptfs_dentry->d_name.name, 420 ecryptfs_dentry->d_name.len); 421 if (rc) { 422 printk(KERN_ERR "%s: Error attempting to encrypt and encode " 423 "filename; rc = [%d]\n", __func__, rc); 424 goto out; 425 } 426 lower_dentry = lookup_one_len_unlocked(encrypted_and_encoded_name, 427 lower_dir_dentry, 428 encrypted_and_encoded_name_size); 429 if (IS_ERR(lower_dentry)) { 430 rc = PTR_ERR(lower_dentry); 431 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned " 432 "[%d] on lower_dentry = [%s]\n", __func__, rc, 433 encrypted_and_encoded_name); 434 goto out; 435 } 436 interpose: 437 rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry, 438 ecryptfs_dir_inode); 439 out: 440 kfree(encrypted_and_encoded_name); 441 return ERR_PTR(rc); 442 } 443 444 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir, 445 struct dentry *new_dentry) 446 { 447 struct dentry *lower_old_dentry; 448 struct dentry *lower_new_dentry; 449 struct dentry *lower_dir_dentry; 450 u64 file_size_save; 451 int rc; 452 453 file_size_save = i_size_read(d_inode(old_dentry)); 454 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 455 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 456 dget(lower_old_dentry); 457 dget(lower_new_dentry); 458 lower_dir_dentry = lock_parent(lower_new_dentry); 459 rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry), 460 lower_new_dentry, NULL); 461 if (rc || d_really_is_negative(lower_new_dentry)) 462 goto out_lock; 463 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb); 464 if (rc) 465 goto out_lock; 466 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry)); 467 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry)); 468 set_nlink(d_inode(old_dentry), 469 ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink); 470 i_size_write(d_inode(new_dentry), file_size_save); 471 out_lock: 472 unlock_dir(lower_dir_dentry); 473 dput(lower_new_dentry); 474 dput(lower_old_dentry); 475 return rc; 476 } 477 478 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) 479 { 480 return ecryptfs_do_unlink(dir, dentry, d_inode(dentry)); 481 } 482 483 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry, 484 const char *symname) 485 { 486 int rc; 487 struct dentry *lower_dentry; 488 struct dentry *lower_dir_dentry; 489 char *encoded_symname; 490 size_t encoded_symlen; 491 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 492 493 lower_dentry = ecryptfs_dentry_to_lower(dentry); 494 dget(lower_dentry); 495 lower_dir_dentry = lock_parent(lower_dentry); 496 mount_crypt_stat = &ecryptfs_superblock_to_private( 497 dir->i_sb)->mount_crypt_stat; 498 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname, 499 &encoded_symlen, 500 mount_crypt_stat, symname, 501 strlen(symname)); 502 if (rc) 503 goto out_lock; 504 rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry, 505 encoded_symname); 506 kfree(encoded_symname); 507 if (rc || d_really_is_negative(lower_dentry)) 508 goto out_lock; 509 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb); 510 if (rc) 511 goto out_lock; 512 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry)); 513 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry)); 514 out_lock: 515 unlock_dir(lower_dir_dentry); 516 dput(lower_dentry); 517 if (d_really_is_negative(dentry)) 518 d_drop(dentry); 519 return rc; 520 } 521 522 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 523 { 524 int rc; 525 struct dentry *lower_dentry; 526 struct dentry *lower_dir_dentry; 527 528 lower_dentry = ecryptfs_dentry_to_lower(dentry); 529 lower_dir_dentry = lock_parent(lower_dentry); 530 rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode); 531 if (rc || d_really_is_negative(lower_dentry)) 532 goto out; 533 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb); 534 if (rc) 535 goto out; 536 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry)); 537 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry)); 538 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink); 539 out: 540 unlock_dir(lower_dir_dentry); 541 if (d_really_is_negative(dentry)) 542 d_drop(dentry); 543 return rc; 544 } 545 546 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) 547 { 548 struct dentry *lower_dentry; 549 struct dentry *lower_dir_dentry; 550 int rc; 551 552 lower_dentry = ecryptfs_dentry_to_lower(dentry); 553 dget(dentry); 554 lower_dir_dentry = lock_parent(lower_dentry); 555 dget(lower_dentry); 556 rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry); 557 dput(lower_dentry); 558 if (!rc && d_really_is_positive(dentry)) 559 clear_nlink(d_inode(dentry)); 560 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry)); 561 set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink); 562 unlock_dir(lower_dir_dentry); 563 if (!rc) 564 d_drop(dentry); 565 dput(dentry); 566 return rc; 567 } 568 569 static int 570 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) 571 { 572 int rc; 573 struct dentry *lower_dentry; 574 struct dentry *lower_dir_dentry; 575 576 lower_dentry = ecryptfs_dentry_to_lower(dentry); 577 lower_dir_dentry = lock_parent(lower_dentry); 578 rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev); 579 if (rc || d_really_is_negative(lower_dentry)) 580 goto out; 581 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb); 582 if (rc) 583 goto out; 584 fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry)); 585 fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry)); 586 out: 587 unlock_dir(lower_dir_dentry); 588 if (d_really_is_negative(dentry)) 589 d_drop(dentry); 590 return rc; 591 } 592 593 static int 594 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, 595 struct inode *new_dir, struct dentry *new_dentry) 596 { 597 int rc; 598 struct dentry *lower_old_dentry; 599 struct dentry *lower_new_dentry; 600 struct dentry *lower_old_dir_dentry; 601 struct dentry *lower_new_dir_dentry; 602 struct dentry *trap = NULL; 603 struct inode *target_inode; 604 605 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 606 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 607 dget(lower_old_dentry); 608 dget(lower_new_dentry); 609 lower_old_dir_dentry = dget_parent(lower_old_dentry); 610 lower_new_dir_dentry = dget_parent(lower_new_dentry); 611 target_inode = d_inode(new_dentry); 612 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 613 /* source should not be ancestor of target */ 614 if (trap == lower_old_dentry) { 615 rc = -EINVAL; 616 goto out_lock; 617 } 618 /* target should not be ancestor of source */ 619 if (trap == lower_new_dentry) { 620 rc = -ENOTEMPTY; 621 goto out_lock; 622 } 623 rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry, 624 d_inode(lower_new_dir_dentry), lower_new_dentry, 625 NULL, 0); 626 if (rc) 627 goto out_lock; 628 if (target_inode) 629 fsstack_copy_attr_all(target_inode, 630 ecryptfs_inode_to_lower(target_inode)); 631 fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry)); 632 if (new_dir != old_dir) 633 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry)); 634 out_lock: 635 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 636 dput(lower_new_dir_dentry); 637 dput(lower_old_dir_dentry); 638 dput(lower_new_dentry); 639 dput(lower_old_dentry); 640 return rc; 641 } 642 643 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz) 644 { 645 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 646 char *lower_buf; 647 char *buf; 648 mm_segment_t old_fs; 649 int rc; 650 651 lower_buf = kmalloc(PATH_MAX, GFP_KERNEL); 652 if (!lower_buf) 653 return ERR_PTR(-ENOMEM); 654 old_fs = get_fs(); 655 set_fs(get_ds()); 656 rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry, 657 (char __user *)lower_buf, 658 PATH_MAX); 659 set_fs(old_fs); 660 if (rc < 0) 661 goto out; 662 rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb, 663 lower_buf, rc); 664 out: 665 kfree(lower_buf); 666 return rc ? ERR_PTR(rc) : buf; 667 } 668 669 static const char *ecryptfs_get_link(struct dentry *dentry, 670 struct inode *inode, 671 struct delayed_call *done) 672 { 673 size_t len; 674 char *buf; 675 676 if (!dentry) 677 return ERR_PTR(-ECHILD); 678 679 buf = ecryptfs_readlink_lower(dentry, &len); 680 if (IS_ERR(buf)) 681 return buf; 682 fsstack_copy_attr_atime(d_inode(dentry), 683 d_inode(ecryptfs_dentry_to_lower(dentry))); 684 buf[len] = '\0'; 685 set_delayed_call(done, kfree_link, buf); 686 return buf; 687 } 688 689 /** 690 * upper_size_to_lower_size 691 * @crypt_stat: Crypt_stat associated with file 692 * @upper_size: Size of the upper file 693 * 694 * Calculate the required size of the lower file based on the 695 * specified size of the upper file. This calculation is based on the 696 * number of headers in the underlying file and the extent size. 697 * 698 * Returns Calculated size of the lower file. 699 */ 700 static loff_t 701 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, 702 loff_t upper_size) 703 { 704 loff_t lower_size; 705 706 lower_size = ecryptfs_lower_header_size(crypt_stat); 707 if (upper_size != 0) { 708 loff_t num_extents; 709 710 num_extents = upper_size >> crypt_stat->extent_shift; 711 if (upper_size & ~crypt_stat->extent_mask) 712 num_extents++; 713 lower_size += (num_extents * crypt_stat->extent_size); 714 } 715 return lower_size; 716 } 717 718 /** 719 * truncate_upper 720 * @dentry: The ecryptfs layer dentry 721 * @ia: Address of the ecryptfs inode's attributes 722 * @lower_ia: Address of the lower inode's attributes 723 * 724 * Function to handle truncations modifying the size of the file. Note 725 * that the file sizes are interpolated. When expanding, we are simply 726 * writing strings of 0's out. When truncating, we truncate the upper 727 * inode and update the lower_ia according to the page index 728 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return, 729 * the caller must use lower_ia in a call to notify_change() to perform 730 * the truncation of the lower inode. 731 * 732 * Returns zero on success; non-zero otherwise 733 */ 734 static int truncate_upper(struct dentry *dentry, struct iattr *ia, 735 struct iattr *lower_ia) 736 { 737 int rc = 0; 738 struct inode *inode = d_inode(dentry); 739 struct ecryptfs_crypt_stat *crypt_stat; 740 loff_t i_size = i_size_read(inode); 741 loff_t lower_size_before_truncate; 742 loff_t lower_size_after_truncate; 743 744 if (unlikely((ia->ia_size == i_size))) { 745 lower_ia->ia_valid &= ~ATTR_SIZE; 746 return 0; 747 } 748 rc = ecryptfs_get_lower_file(dentry, inode); 749 if (rc) 750 return rc; 751 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat; 752 /* Switch on growing or shrinking file */ 753 if (ia->ia_size > i_size) { 754 char zero[] = { 0x00 }; 755 756 lower_ia->ia_valid &= ~ATTR_SIZE; 757 /* Write a single 0 at the last position of the file; 758 * this triggers code that will fill in 0's throughout 759 * the intermediate portion of the previous end of the 760 * file and the new and of the file */ 761 rc = ecryptfs_write(inode, zero, 762 (ia->ia_size - 1), 1); 763 } else { /* ia->ia_size < i_size_read(inode) */ 764 /* We're chopping off all the pages down to the page 765 * in which ia->ia_size is located. Fill in the end of 766 * that page from (ia->ia_size & ~PAGE_MASK) to 767 * PAGE_SIZE with zeros. */ 768 size_t num_zeros = (PAGE_SIZE 769 - (ia->ia_size & ~PAGE_MASK)); 770 771 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { 772 truncate_setsize(inode, ia->ia_size); 773 lower_ia->ia_size = ia->ia_size; 774 lower_ia->ia_valid |= ATTR_SIZE; 775 goto out; 776 } 777 if (num_zeros) { 778 char *zeros_virt; 779 780 zeros_virt = kzalloc(num_zeros, GFP_KERNEL); 781 if (!zeros_virt) { 782 rc = -ENOMEM; 783 goto out; 784 } 785 rc = ecryptfs_write(inode, zeros_virt, 786 ia->ia_size, num_zeros); 787 kfree(zeros_virt); 788 if (rc) { 789 printk(KERN_ERR "Error attempting to zero out " 790 "the remainder of the end page on " 791 "reducing truncate; rc = [%d]\n", rc); 792 goto out; 793 } 794 } 795 truncate_setsize(inode, ia->ia_size); 796 rc = ecryptfs_write_inode_size_to_metadata(inode); 797 if (rc) { 798 printk(KERN_ERR "Problem with " 799 "ecryptfs_write_inode_size_to_metadata; " 800 "rc = [%d]\n", rc); 801 goto out; 802 } 803 /* We are reducing the size of the ecryptfs file, and need to 804 * know if we need to reduce the size of the lower file. */ 805 lower_size_before_truncate = 806 upper_size_to_lower_size(crypt_stat, i_size); 807 lower_size_after_truncate = 808 upper_size_to_lower_size(crypt_stat, ia->ia_size); 809 if (lower_size_after_truncate < lower_size_before_truncate) { 810 lower_ia->ia_size = lower_size_after_truncate; 811 lower_ia->ia_valid |= ATTR_SIZE; 812 } else 813 lower_ia->ia_valid &= ~ATTR_SIZE; 814 } 815 out: 816 ecryptfs_put_lower_file(inode); 817 return rc; 818 } 819 820 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset) 821 { 822 struct ecryptfs_crypt_stat *crypt_stat; 823 loff_t lower_oldsize, lower_newsize; 824 825 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; 826 lower_oldsize = upper_size_to_lower_size(crypt_stat, 827 i_size_read(inode)); 828 lower_newsize = upper_size_to_lower_size(crypt_stat, offset); 829 if (lower_newsize > lower_oldsize) { 830 /* 831 * The eCryptfs inode and the new *lower* size are mixed here 832 * because we may not have the lower i_mutex held and/or it may 833 * not be appropriate to call inode_newsize_ok() with inodes 834 * from other filesystems. 835 */ 836 return inode_newsize_ok(inode, lower_newsize); 837 } 838 839 return 0; 840 } 841 842 /** 843 * ecryptfs_truncate 844 * @dentry: The ecryptfs layer dentry 845 * @new_length: The length to expand the file to 846 * 847 * Simple function that handles the truncation of an eCryptfs inode and 848 * its corresponding lower inode. 849 * 850 * Returns zero on success; non-zero otherwise 851 */ 852 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) 853 { 854 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length }; 855 struct iattr lower_ia = { .ia_valid = 0 }; 856 int rc; 857 858 rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length); 859 if (rc) 860 return rc; 861 862 rc = truncate_upper(dentry, &ia, &lower_ia); 863 if (!rc && lower_ia.ia_valid & ATTR_SIZE) { 864 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 865 866 inode_lock(d_inode(lower_dentry)); 867 rc = notify_change(lower_dentry, &lower_ia, NULL); 868 inode_unlock(d_inode(lower_dentry)); 869 } 870 return rc; 871 } 872 873 static int 874 ecryptfs_permission(struct inode *inode, int mask) 875 { 876 return inode_permission(ecryptfs_inode_to_lower(inode), mask); 877 } 878 879 /** 880 * ecryptfs_setattr 881 * @dentry: dentry handle to the inode to modify 882 * @ia: Structure with flags of what to change and values 883 * 884 * Updates the metadata of an inode. If the update is to the size 885 * i.e. truncation, then ecryptfs_truncate will handle the size modification 886 * of both the ecryptfs inode and the lower inode. 887 * 888 * All other metadata changes will be passed right to the lower filesystem, 889 * and we will just update our inode to look like the lower. 890 */ 891 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) 892 { 893 int rc = 0; 894 struct dentry *lower_dentry; 895 struct iattr lower_ia; 896 struct inode *inode; 897 struct inode *lower_inode; 898 struct ecryptfs_crypt_stat *crypt_stat; 899 900 crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat; 901 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) 902 ecryptfs_init_crypt_stat(crypt_stat); 903 inode = d_inode(dentry); 904 lower_inode = ecryptfs_inode_to_lower(inode); 905 lower_dentry = ecryptfs_dentry_to_lower(dentry); 906 mutex_lock(&crypt_stat->cs_mutex); 907 if (d_is_dir(dentry)) 908 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 909 else if (d_is_reg(dentry) 910 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) 911 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) { 912 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 913 914 mount_crypt_stat = &ecryptfs_superblock_to_private( 915 dentry->d_sb)->mount_crypt_stat; 916 rc = ecryptfs_get_lower_file(dentry, inode); 917 if (rc) { 918 mutex_unlock(&crypt_stat->cs_mutex); 919 goto out; 920 } 921 rc = ecryptfs_read_metadata(dentry); 922 ecryptfs_put_lower_file(inode); 923 if (rc) { 924 if (!(mount_crypt_stat->flags 925 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { 926 rc = -EIO; 927 printk(KERN_WARNING "Either the lower file " 928 "is not in a valid eCryptfs format, " 929 "or the key could not be retrieved. " 930 "Plaintext passthrough mode is not " 931 "enabled; returning -EIO\n"); 932 mutex_unlock(&crypt_stat->cs_mutex); 933 goto out; 934 } 935 rc = 0; 936 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED 937 | ECRYPTFS_ENCRYPTED); 938 } 939 } 940 mutex_unlock(&crypt_stat->cs_mutex); 941 942 rc = inode_change_ok(inode, ia); 943 if (rc) 944 goto out; 945 if (ia->ia_valid & ATTR_SIZE) { 946 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size); 947 if (rc) 948 goto out; 949 } 950 951 memcpy(&lower_ia, ia, sizeof(lower_ia)); 952 if (ia->ia_valid & ATTR_FILE) 953 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file); 954 if (ia->ia_valid & ATTR_SIZE) { 955 rc = truncate_upper(dentry, ia, &lower_ia); 956 if (rc < 0) 957 goto out; 958 } 959 960 /* 961 * mode change is for clearing setuid/setgid bits. Allow lower fs 962 * to interpret this in its own way. 963 */ 964 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) 965 lower_ia.ia_valid &= ~ATTR_MODE; 966 967 inode_lock(d_inode(lower_dentry)); 968 rc = notify_change(lower_dentry, &lower_ia, NULL); 969 inode_unlock(d_inode(lower_dentry)); 970 out: 971 fsstack_copy_attr_all(inode, lower_inode); 972 return rc; 973 } 974 975 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry, 976 struct kstat *stat) 977 { 978 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 979 int rc = 0; 980 981 mount_crypt_stat = &ecryptfs_superblock_to_private( 982 dentry->d_sb)->mount_crypt_stat; 983 generic_fillattr(d_inode(dentry), stat); 984 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { 985 char *target; 986 size_t targetsiz; 987 988 target = ecryptfs_readlink_lower(dentry, &targetsiz); 989 if (!IS_ERR(target)) { 990 kfree(target); 991 stat->size = targetsiz; 992 } else { 993 rc = PTR_ERR(target); 994 } 995 } 996 return rc; 997 } 998 999 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry, 1000 struct kstat *stat) 1001 { 1002 struct kstat lower_stat; 1003 int rc; 1004 1005 rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat); 1006 if (!rc) { 1007 fsstack_copy_attr_all(d_inode(dentry), 1008 ecryptfs_inode_to_lower(d_inode(dentry))); 1009 generic_fillattr(d_inode(dentry), stat); 1010 stat->blocks = lower_stat.blocks; 1011 } 1012 return rc; 1013 } 1014 1015 int 1016 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value, 1017 size_t size, int flags) 1018 { 1019 int rc = 0; 1020 struct dentry *lower_dentry; 1021 1022 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1023 if (!d_inode(lower_dentry)->i_op->setxattr) { 1024 rc = -EOPNOTSUPP; 1025 goto out; 1026 } 1027 1028 rc = vfs_setxattr(lower_dentry, name, value, size, flags); 1029 if (!rc && d_really_is_positive(dentry)) 1030 fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry)); 1031 out: 1032 return rc; 1033 } 1034 1035 ssize_t 1036 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name, 1037 void *value, size_t size) 1038 { 1039 int rc = 0; 1040 1041 if (!d_inode(lower_dentry)->i_op->getxattr) { 1042 rc = -EOPNOTSUPP; 1043 goto out; 1044 } 1045 inode_lock(d_inode(lower_dentry)); 1046 rc = d_inode(lower_dentry)->i_op->getxattr(lower_dentry, name, value, 1047 size); 1048 inode_unlock(d_inode(lower_dentry)); 1049 out: 1050 return rc; 1051 } 1052 1053 static ssize_t 1054 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value, 1055 size_t size) 1056 { 1057 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name, 1058 value, size); 1059 } 1060 1061 static ssize_t 1062 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size) 1063 { 1064 int rc = 0; 1065 struct dentry *lower_dentry; 1066 1067 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1068 if (!d_inode(lower_dentry)->i_op->listxattr) { 1069 rc = -EOPNOTSUPP; 1070 goto out; 1071 } 1072 inode_lock(d_inode(lower_dentry)); 1073 rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size); 1074 inode_unlock(d_inode(lower_dentry)); 1075 out: 1076 return rc; 1077 } 1078 1079 static int ecryptfs_removexattr(struct dentry *dentry, const char *name) 1080 { 1081 int rc = 0; 1082 struct dentry *lower_dentry; 1083 1084 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1085 if (!d_inode(lower_dentry)->i_op->removexattr) { 1086 rc = -EOPNOTSUPP; 1087 goto out; 1088 } 1089 inode_lock(d_inode(lower_dentry)); 1090 rc = d_inode(lower_dentry)->i_op->removexattr(lower_dentry, name); 1091 inode_unlock(d_inode(lower_dentry)); 1092 out: 1093 return rc; 1094 } 1095 1096 const struct inode_operations ecryptfs_symlink_iops = { 1097 .readlink = generic_readlink, 1098 .get_link = ecryptfs_get_link, 1099 .permission = ecryptfs_permission, 1100 .setattr = ecryptfs_setattr, 1101 .getattr = ecryptfs_getattr_link, 1102 .setxattr = ecryptfs_setxattr, 1103 .getxattr = ecryptfs_getxattr, 1104 .listxattr = ecryptfs_listxattr, 1105 .removexattr = ecryptfs_removexattr 1106 }; 1107 1108 const struct inode_operations ecryptfs_dir_iops = { 1109 .create = ecryptfs_create, 1110 .lookup = ecryptfs_lookup, 1111 .link = ecryptfs_link, 1112 .unlink = ecryptfs_unlink, 1113 .symlink = ecryptfs_symlink, 1114 .mkdir = ecryptfs_mkdir, 1115 .rmdir = ecryptfs_rmdir, 1116 .mknod = ecryptfs_mknod, 1117 .rename = ecryptfs_rename, 1118 .permission = ecryptfs_permission, 1119 .setattr = ecryptfs_setattr, 1120 .setxattr = ecryptfs_setxattr, 1121 .getxattr = ecryptfs_getxattr, 1122 .listxattr = ecryptfs_listxattr, 1123 .removexattr = ecryptfs_removexattr 1124 }; 1125 1126 const struct inode_operations ecryptfs_main_iops = { 1127 .permission = ecryptfs_permission, 1128 .setattr = ecryptfs_setattr, 1129 .getattr = ecryptfs_getattr, 1130 .setxattr = ecryptfs_setxattr, 1131 .getxattr = ecryptfs_getxattr, 1132 .listxattr = ecryptfs_listxattr, 1133 .removexattr = ecryptfs_removexattr 1134 }; 1135