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 <linux/slab.h> 35 #include <linux/xattr.h> 36 #include <asm/unaligned.h> 37 #include "ecryptfs_kernel.h" 38 39 static struct dentry *lock_parent(struct dentry *dentry) 40 { 41 struct dentry *dir; 42 43 dir = dget_parent(dentry); 44 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT); 45 return dir; 46 } 47 48 static void unlock_dir(struct dentry *dir) 49 { 50 mutex_unlock(&dir->d_inode->i_mutex); 51 dput(dir); 52 } 53 54 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode) 55 { 56 if (ecryptfs_inode_to_lower(inode) == (struct inode *)lower_inode) 57 return 1; 58 return 0; 59 } 60 61 static int ecryptfs_inode_set(struct inode *inode, void *opaque) 62 { 63 struct inode *lower_inode = opaque; 64 65 ecryptfs_set_inode_lower(inode, lower_inode); 66 fsstack_copy_attr_all(inode, lower_inode); 67 /* i_size will be overwritten for encrypted regular files */ 68 fsstack_copy_inode_size(inode, lower_inode); 69 inode->i_ino = lower_inode->i_ino; 70 inode->i_version++; 71 inode->i_mapping->a_ops = &ecryptfs_aops; 72 73 if (S_ISLNK(inode->i_mode)) 74 inode->i_op = &ecryptfs_symlink_iops; 75 else if (S_ISDIR(inode->i_mode)) 76 inode->i_op = &ecryptfs_dir_iops; 77 else 78 inode->i_op = &ecryptfs_main_iops; 79 80 if (S_ISDIR(inode->i_mode)) 81 inode->i_fop = &ecryptfs_dir_fops; 82 else if (special_file(inode->i_mode)) 83 init_special_inode(inode, inode->i_mode, inode->i_rdev); 84 else 85 inode->i_fop = &ecryptfs_main_fops; 86 87 return 0; 88 } 89 90 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode, 91 struct super_block *sb) 92 { 93 struct inode *inode; 94 95 if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb)) 96 return ERR_PTR(-EXDEV); 97 if (!igrab(lower_inode)) 98 return ERR_PTR(-ESTALE); 99 inode = iget5_locked(sb, (unsigned long)lower_inode, 100 ecryptfs_inode_test, ecryptfs_inode_set, 101 lower_inode); 102 if (!inode) { 103 iput(lower_inode); 104 return ERR_PTR(-EACCES); 105 } 106 if (!(inode->i_state & I_NEW)) 107 iput(lower_inode); 108 109 return inode; 110 } 111 112 struct inode *ecryptfs_get_inode(struct inode *lower_inode, 113 struct super_block *sb) 114 { 115 struct inode *inode = __ecryptfs_get_inode(lower_inode, sb); 116 117 if (!IS_ERR(inode) && (inode->i_state & I_NEW)) 118 unlock_new_inode(inode); 119 120 return inode; 121 } 122 123 /** 124 * ecryptfs_interpose 125 * @lower_dentry: Existing dentry in the lower filesystem 126 * @dentry: ecryptfs' dentry 127 * @sb: ecryptfs's super_block 128 * 129 * Interposes upper and lower dentries. 130 * 131 * Returns zero on success; non-zero otherwise 132 */ 133 static int ecryptfs_interpose(struct dentry *lower_dentry, 134 struct dentry *dentry, struct super_block *sb) 135 { 136 struct inode *inode = ecryptfs_get_inode(lower_dentry->d_inode, sb); 137 138 if (IS_ERR(inode)) 139 return PTR_ERR(inode); 140 d_instantiate(dentry, inode); 141 142 return 0; 143 } 144 145 /** 146 * ecryptfs_create_underlying_file 147 * @lower_dir_inode: inode of the parent in the lower fs of the new file 148 * @dentry: New file's dentry 149 * @mode: The mode of the new file 150 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount 151 * 152 * Creates the file in the lower file system. 153 * 154 * Returns zero on success; non-zero on error condition 155 */ 156 static int 157 ecryptfs_create_underlying_file(struct inode *lower_dir_inode, 158 struct dentry *dentry, int mode, 159 struct nameidata *nd) 160 { 161 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 162 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry); 163 struct dentry *dentry_save; 164 struct vfsmount *vfsmount_save; 165 unsigned int flags_save; 166 int rc; 167 168 if (nd) { 169 dentry_save = nd->path.dentry; 170 vfsmount_save = nd->path.mnt; 171 flags_save = nd->flags; 172 nd->path.dentry = lower_dentry; 173 nd->path.mnt = lower_mnt; 174 nd->flags &= ~LOOKUP_OPEN; 175 } 176 rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd); 177 if (nd) { 178 nd->path.dentry = dentry_save; 179 nd->path.mnt = vfsmount_save; 180 nd->flags = flags_save; 181 } 182 return rc; 183 } 184 185 /** 186 * ecryptfs_do_create 187 * @directory_inode: inode of the new file's dentry's parent in ecryptfs 188 * @ecryptfs_dentry: New file's dentry in ecryptfs 189 * @mode: The mode of the new file 190 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount 191 * 192 * Creates the underlying file and the eCryptfs inode which will link to 193 * it. It will also update the eCryptfs directory inode to mimic the 194 * stat of the lower directory inode. 195 * 196 * Returns zero on success; non-zero on error condition 197 */ 198 static int 199 ecryptfs_do_create(struct inode *directory_inode, 200 struct dentry *ecryptfs_dentry, int mode, 201 struct nameidata *nd) 202 { 203 int rc; 204 struct dentry *lower_dentry; 205 struct dentry *lower_dir_dentry; 206 207 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); 208 lower_dir_dentry = lock_parent(lower_dentry); 209 if (IS_ERR(lower_dir_dentry)) { 210 ecryptfs_printk(KERN_ERR, "Error locking directory of " 211 "dentry\n"); 212 rc = PTR_ERR(lower_dir_dentry); 213 goto out; 214 } 215 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode, 216 ecryptfs_dentry, mode, nd); 217 if (rc) { 218 printk(KERN_ERR "%s: Failure to create dentry in lower fs; " 219 "rc = [%d]\n", __func__, rc); 220 goto out_lock; 221 } 222 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry, 223 directory_inode->i_sb); 224 if (rc) { 225 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n"); 226 goto out_lock; 227 } 228 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode); 229 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode); 230 out_lock: 231 unlock_dir(lower_dir_dentry); 232 out: 233 return rc; 234 } 235 236 /** 237 * ecryptfs_initialize_file 238 * 239 * Cause the file to be changed from a basic empty file to an ecryptfs 240 * file with a header and first data page. 241 * 242 * Returns zero on success 243 */ 244 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry) 245 { 246 struct ecryptfs_crypt_stat *crypt_stat = 247 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; 248 int rc = 0; 249 250 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { 251 ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); 252 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 253 goto out; 254 } 255 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n"); 256 rc = ecryptfs_new_file_context(ecryptfs_dentry); 257 if (rc) { 258 ecryptfs_printk(KERN_ERR, "Error creating new file " 259 "context; rc = [%d]\n", rc); 260 goto out; 261 } 262 rc = ecryptfs_get_lower_file(ecryptfs_dentry, 263 ecryptfs_dentry->d_inode); 264 if (rc) { 265 printk(KERN_ERR "%s: Error attempting to initialize " 266 "the lower file for the dentry with name " 267 "[%s]; rc = [%d]\n", __func__, 268 ecryptfs_dentry->d_name.name, rc); 269 goto out; 270 } 271 rc = ecryptfs_write_metadata(ecryptfs_dentry); 272 if (rc) 273 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc); 274 ecryptfs_put_lower_file(ecryptfs_dentry->d_inode); 275 out: 276 return rc; 277 } 278 279 /** 280 * ecryptfs_create 281 * @dir: The inode of the directory in which to create the file. 282 * @dentry: The eCryptfs dentry 283 * @mode: The mode of the new file. 284 * @nd: nameidata 285 * 286 * Creates a new file. 287 * 288 * Returns zero on success; non-zero on error condition 289 */ 290 static int 291 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry, 292 int mode, struct nameidata *nd) 293 { 294 int rc; 295 296 /* ecryptfs_do_create() calls ecryptfs_interpose() */ 297 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd); 298 if (unlikely(rc)) { 299 ecryptfs_printk(KERN_WARNING, "Failed to create file in" 300 "lower filesystem\n"); 301 goto out; 302 } 303 /* At this point, a file exists on "disk"; we need to make sure 304 * that this on disk file is prepared to be an ecryptfs file */ 305 rc = ecryptfs_initialize_file(ecryptfs_dentry); 306 out: 307 return rc; 308 } 309 310 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode) 311 { 312 struct ecryptfs_crypt_stat *crypt_stat; 313 int rc; 314 315 rc = ecryptfs_get_lower_file(dentry, inode); 316 if (rc) { 317 printk(KERN_ERR "%s: Error attempting to initialize " 318 "the lower file for the dentry with name " 319 "[%s]; rc = [%d]\n", __func__, 320 dentry->d_name.name, rc); 321 return rc; 322 } 323 324 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; 325 /* TODO: lock for crypt_stat comparison */ 326 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) 327 ecryptfs_set_default_sizes(crypt_stat); 328 329 rc = ecryptfs_read_and_validate_header_region(inode); 330 ecryptfs_put_lower_file(inode); 331 if (rc) { 332 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode); 333 if (!rc) 334 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; 335 } 336 337 /* Must return 0 to allow non-eCryptfs files to be looked up, too */ 338 return 0; 339 } 340 341 /** 342 * ecryptfs_lookup_interpose - Dentry interposition for a lookup 343 */ 344 static int ecryptfs_lookup_interpose(struct dentry *dentry, 345 struct dentry *lower_dentry, 346 struct inode *dir_inode) 347 { 348 struct inode *inode, *lower_inode = lower_dentry->d_inode; 349 struct ecryptfs_dentry_info *dentry_info; 350 struct vfsmount *lower_mnt; 351 int rc = 0; 352 353 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent)); 354 fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode); 355 BUG_ON(!lower_dentry->d_count); 356 357 dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL); 358 ecryptfs_set_dentry_private(dentry, dentry_info); 359 if (!dentry_info) { 360 printk(KERN_ERR "%s: Out of memory whilst attempting " 361 "to allocate ecryptfs_dentry_info struct\n", 362 __func__); 363 dput(lower_dentry); 364 mntput(lower_mnt); 365 d_drop(dentry); 366 return -ENOMEM; 367 } 368 ecryptfs_set_dentry_lower(dentry, lower_dentry); 369 ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt); 370 371 if (!lower_dentry->d_inode) { 372 /* We want to add because we couldn't find in lower */ 373 d_add(dentry, NULL); 374 return 0; 375 } 376 inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb); 377 if (IS_ERR(inode)) { 378 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n", 379 __func__, PTR_ERR(inode)); 380 return PTR_ERR(inode); 381 } 382 if (S_ISREG(inode->i_mode)) { 383 rc = ecryptfs_i_size_read(dentry, inode); 384 if (rc) { 385 make_bad_inode(inode); 386 return rc; 387 } 388 } 389 390 if (inode->i_state & I_NEW) 391 unlock_new_inode(inode); 392 d_add(dentry, inode); 393 394 return rc; 395 } 396 397 /** 398 * ecryptfs_lookup 399 * @ecryptfs_dir_inode: The eCryptfs directory inode 400 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up 401 * @ecryptfs_nd: nameidata; may be NULL 402 * 403 * Find a file on disk. If the file does not exist, then we'll add it to the 404 * dentry cache and continue on to read it from the disk. 405 */ 406 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode, 407 struct dentry *ecryptfs_dentry, 408 struct nameidata *ecryptfs_nd) 409 { 410 char *encrypted_and_encoded_name = NULL; 411 size_t encrypted_and_encoded_name_size; 412 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 413 struct dentry *lower_dir_dentry, *lower_dentry; 414 int rc = 0; 415 416 if ((ecryptfs_dentry->d_name.len == 1 417 && !strcmp(ecryptfs_dentry->d_name.name, ".")) 418 || (ecryptfs_dentry->d_name.len == 2 419 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) { 420 goto out_d_drop; 421 } 422 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent); 423 mutex_lock(&lower_dir_dentry->d_inode->i_mutex); 424 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name, 425 lower_dir_dentry, 426 ecryptfs_dentry->d_name.len); 427 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex); 428 if (IS_ERR(lower_dentry)) { 429 rc = PTR_ERR(lower_dentry); 430 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned " 431 "[%d] on lower_dentry = [%s]\n", __func__, rc, 432 encrypted_and_encoded_name); 433 goto out_d_drop; 434 } 435 if (lower_dentry->d_inode) 436 goto interpose; 437 mount_crypt_stat = &ecryptfs_superblock_to_private( 438 ecryptfs_dentry->d_sb)->mount_crypt_stat; 439 if (!(mount_crypt_stat 440 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) 441 goto interpose; 442 dput(lower_dentry); 443 rc = ecryptfs_encrypt_and_encode_filename( 444 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size, 445 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name, 446 ecryptfs_dentry->d_name.len); 447 if (rc) { 448 printk(KERN_ERR "%s: Error attempting to encrypt and encode " 449 "filename; rc = [%d]\n", __func__, rc); 450 goto out_d_drop; 451 } 452 mutex_lock(&lower_dir_dentry->d_inode->i_mutex); 453 lower_dentry = lookup_one_len(encrypted_and_encoded_name, 454 lower_dir_dentry, 455 encrypted_and_encoded_name_size); 456 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex); 457 if (IS_ERR(lower_dentry)) { 458 rc = PTR_ERR(lower_dentry); 459 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned " 460 "[%d] on lower_dentry = [%s]\n", __func__, rc, 461 encrypted_and_encoded_name); 462 goto out_d_drop; 463 } 464 interpose: 465 rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry, 466 ecryptfs_dir_inode); 467 goto out; 468 out_d_drop: 469 d_drop(ecryptfs_dentry); 470 out: 471 kfree(encrypted_and_encoded_name); 472 return ERR_PTR(rc); 473 } 474 475 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir, 476 struct dentry *new_dentry) 477 { 478 struct dentry *lower_old_dentry; 479 struct dentry *lower_new_dentry; 480 struct dentry *lower_dir_dentry; 481 u64 file_size_save; 482 int rc; 483 484 file_size_save = i_size_read(old_dentry->d_inode); 485 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 486 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 487 dget(lower_old_dentry); 488 dget(lower_new_dentry); 489 lower_dir_dentry = lock_parent(lower_new_dentry); 490 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode, 491 lower_new_dentry); 492 if (rc || !lower_new_dentry->d_inode) 493 goto out_lock; 494 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb); 495 if (rc) 496 goto out_lock; 497 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 498 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 499 old_dentry->d_inode->i_nlink = 500 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink; 501 i_size_write(new_dentry->d_inode, file_size_save); 502 out_lock: 503 unlock_dir(lower_dir_dentry); 504 dput(lower_new_dentry); 505 dput(lower_old_dentry); 506 return rc; 507 } 508 509 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) 510 { 511 int rc = 0; 512 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 513 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); 514 struct dentry *lower_dir_dentry; 515 516 dget(lower_dentry); 517 lower_dir_dentry = lock_parent(lower_dentry); 518 rc = vfs_unlink(lower_dir_inode, lower_dentry); 519 if (rc) { 520 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); 521 goto out_unlock; 522 } 523 fsstack_copy_attr_times(dir, lower_dir_inode); 524 dentry->d_inode->i_nlink = 525 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink; 526 dentry->d_inode->i_ctime = dir->i_ctime; 527 d_drop(dentry); 528 out_unlock: 529 unlock_dir(lower_dir_dentry); 530 dput(lower_dentry); 531 return rc; 532 } 533 534 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry, 535 const char *symname) 536 { 537 int rc; 538 struct dentry *lower_dentry; 539 struct dentry *lower_dir_dentry; 540 char *encoded_symname; 541 size_t encoded_symlen; 542 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 543 544 lower_dentry = ecryptfs_dentry_to_lower(dentry); 545 dget(lower_dentry); 546 lower_dir_dentry = lock_parent(lower_dentry); 547 mount_crypt_stat = &ecryptfs_superblock_to_private( 548 dir->i_sb)->mount_crypt_stat; 549 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname, 550 &encoded_symlen, 551 NULL, 552 mount_crypt_stat, symname, 553 strlen(symname)); 554 if (rc) 555 goto out_lock; 556 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry, 557 encoded_symname); 558 kfree(encoded_symname); 559 if (rc || !lower_dentry->d_inode) 560 goto out_lock; 561 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb); 562 if (rc) 563 goto out_lock; 564 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 565 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 566 out_lock: 567 unlock_dir(lower_dir_dentry); 568 dput(lower_dentry); 569 if (!dentry->d_inode) 570 d_drop(dentry); 571 return rc; 572 } 573 574 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 575 { 576 int rc; 577 struct dentry *lower_dentry; 578 struct dentry *lower_dir_dentry; 579 580 lower_dentry = ecryptfs_dentry_to_lower(dentry); 581 lower_dir_dentry = lock_parent(lower_dentry); 582 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode); 583 if (rc || !lower_dentry->d_inode) 584 goto out; 585 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb); 586 if (rc) 587 goto out; 588 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 589 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 590 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 591 out: 592 unlock_dir(lower_dir_dentry); 593 if (!dentry->d_inode) 594 d_drop(dentry); 595 return rc; 596 } 597 598 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) 599 { 600 struct dentry *lower_dentry; 601 struct dentry *lower_dir_dentry; 602 int rc; 603 604 lower_dentry = ecryptfs_dentry_to_lower(dentry); 605 dget(dentry); 606 lower_dir_dentry = lock_parent(lower_dentry); 607 dget(lower_dentry); 608 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry); 609 dput(lower_dentry); 610 if (!rc && dentry->d_inode) 611 clear_nlink(dentry->d_inode); 612 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 613 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 614 unlock_dir(lower_dir_dentry); 615 if (!rc) 616 d_drop(dentry); 617 dput(dentry); 618 return rc; 619 } 620 621 static int 622 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 623 { 624 int rc; 625 struct dentry *lower_dentry; 626 struct dentry *lower_dir_dentry; 627 628 lower_dentry = ecryptfs_dentry_to_lower(dentry); 629 lower_dir_dentry = lock_parent(lower_dentry); 630 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); 631 if (rc || !lower_dentry->d_inode) 632 goto out; 633 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb); 634 if (rc) 635 goto out; 636 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 637 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 638 out: 639 unlock_dir(lower_dir_dentry); 640 if (!dentry->d_inode) 641 d_drop(dentry); 642 return rc; 643 } 644 645 static int 646 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, 647 struct inode *new_dir, struct dentry *new_dentry) 648 { 649 int rc; 650 struct dentry *lower_old_dentry; 651 struct dentry *lower_new_dentry; 652 struct dentry *lower_old_dir_dentry; 653 struct dentry *lower_new_dir_dentry; 654 struct dentry *trap = NULL; 655 656 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 657 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 658 dget(lower_old_dentry); 659 dget(lower_new_dentry); 660 lower_old_dir_dentry = dget_parent(lower_old_dentry); 661 lower_new_dir_dentry = dget_parent(lower_new_dentry); 662 trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 663 /* source should not be ancestor of target */ 664 if (trap == lower_old_dentry) { 665 rc = -EINVAL; 666 goto out_lock; 667 } 668 /* target should not be ancestor of source */ 669 if (trap == lower_new_dentry) { 670 rc = -ENOTEMPTY; 671 goto out_lock; 672 } 673 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry, 674 lower_new_dir_dentry->d_inode, lower_new_dentry); 675 if (rc) 676 goto out_lock; 677 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode); 678 if (new_dir != old_dir) 679 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode); 680 out_lock: 681 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 682 dput(lower_new_dir_dentry); 683 dput(lower_old_dir_dentry); 684 dput(lower_new_dentry); 685 dput(lower_old_dentry); 686 return rc; 687 } 688 689 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf, 690 size_t *bufsiz) 691 { 692 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 693 char *lower_buf; 694 size_t lower_bufsiz = PATH_MAX; 695 mm_segment_t old_fs; 696 int rc; 697 698 lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL); 699 if (!lower_buf) { 700 rc = -ENOMEM; 701 goto out; 702 } 703 old_fs = get_fs(); 704 set_fs(get_ds()); 705 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry, 706 (char __user *)lower_buf, 707 lower_bufsiz); 708 set_fs(old_fs); 709 if (rc < 0) 710 goto out; 711 lower_bufsiz = rc; 712 rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry, 713 lower_buf, lower_bufsiz); 714 out: 715 kfree(lower_buf); 716 return rc; 717 } 718 719 static int 720 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz) 721 { 722 char *kbuf; 723 size_t kbufsiz, copied; 724 int rc; 725 726 rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz); 727 if (rc) 728 goto out; 729 copied = min_t(size_t, bufsiz, kbufsiz); 730 rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied; 731 kfree(kbuf); 732 fsstack_copy_attr_atime(dentry->d_inode, 733 ecryptfs_dentry_to_lower(dentry)->d_inode); 734 out: 735 return rc; 736 } 737 738 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd) 739 { 740 char *buf; 741 int len = PAGE_SIZE, rc; 742 mm_segment_t old_fs; 743 744 /* Released in ecryptfs_put_link(); only release here on error */ 745 buf = kmalloc(len, GFP_KERNEL); 746 if (!buf) { 747 buf = ERR_PTR(-ENOMEM); 748 goto out; 749 } 750 old_fs = get_fs(); 751 set_fs(get_ds()); 752 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len); 753 set_fs(old_fs); 754 if (rc < 0) { 755 kfree(buf); 756 buf = ERR_PTR(rc); 757 } else 758 buf[rc] = '\0'; 759 out: 760 nd_set_link(nd, buf); 761 return NULL; 762 } 763 764 static void 765 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr) 766 { 767 char *buf = nd_get_link(nd); 768 if (!IS_ERR(buf)) { 769 /* Free the char* */ 770 kfree(buf); 771 } 772 } 773 774 /** 775 * upper_size_to_lower_size 776 * @crypt_stat: Crypt_stat associated with file 777 * @upper_size: Size of the upper file 778 * 779 * Calculate the required size of the lower file based on the 780 * specified size of the upper file. This calculation is based on the 781 * number of headers in the underlying file and the extent size. 782 * 783 * Returns Calculated size of the lower file. 784 */ 785 static loff_t 786 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, 787 loff_t upper_size) 788 { 789 loff_t lower_size; 790 791 lower_size = ecryptfs_lower_header_size(crypt_stat); 792 if (upper_size != 0) { 793 loff_t num_extents; 794 795 num_extents = upper_size >> crypt_stat->extent_shift; 796 if (upper_size & ~crypt_stat->extent_mask) 797 num_extents++; 798 lower_size += (num_extents * crypt_stat->extent_size); 799 } 800 return lower_size; 801 } 802 803 /** 804 * truncate_upper 805 * @dentry: The ecryptfs layer dentry 806 * @ia: Address of the ecryptfs inode's attributes 807 * @lower_ia: Address of the lower inode's attributes 808 * 809 * Function to handle truncations modifying the size of the file. Note 810 * that the file sizes are interpolated. When expanding, we are simply 811 * writing strings of 0's out. When truncating, we truncate the upper 812 * inode and update the lower_ia according to the page index 813 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return, 814 * the caller must use lower_ia in a call to notify_change() to perform 815 * the truncation of the lower inode. 816 * 817 * Returns zero on success; non-zero otherwise 818 */ 819 static int truncate_upper(struct dentry *dentry, struct iattr *ia, 820 struct iattr *lower_ia) 821 { 822 int rc = 0; 823 struct inode *inode = dentry->d_inode; 824 struct ecryptfs_crypt_stat *crypt_stat; 825 loff_t i_size = i_size_read(inode); 826 loff_t lower_size_before_truncate; 827 loff_t lower_size_after_truncate; 828 829 if (unlikely((ia->ia_size == i_size))) { 830 lower_ia->ia_valid &= ~ATTR_SIZE; 831 return 0; 832 } 833 rc = ecryptfs_get_lower_file(dentry, inode); 834 if (rc) 835 return rc; 836 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 837 /* Switch on growing or shrinking file */ 838 if (ia->ia_size > i_size) { 839 char zero[] = { 0x00 }; 840 841 lower_ia->ia_valid &= ~ATTR_SIZE; 842 /* Write a single 0 at the last position of the file; 843 * this triggers code that will fill in 0's throughout 844 * the intermediate portion of the previous end of the 845 * file and the new and of the file */ 846 rc = ecryptfs_write(inode, zero, 847 (ia->ia_size - 1), 1); 848 } else { /* ia->ia_size < i_size_read(inode) */ 849 /* We're chopping off all the pages down to the page 850 * in which ia->ia_size is located. Fill in the end of 851 * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to 852 * PAGE_CACHE_SIZE with zeros. */ 853 size_t num_zeros = (PAGE_CACHE_SIZE 854 - (ia->ia_size & ~PAGE_CACHE_MASK)); 855 856 857 /* 858 * XXX(truncate) this should really happen at the begginning 859 * of ->setattr. But the code is too messy to that as part 860 * of a larger patch. ecryptfs is also totally missing out 861 * on the inode_change_ok check at the beginning of 862 * ->setattr while would include this. 863 */ 864 rc = inode_newsize_ok(inode, ia->ia_size); 865 if (rc) 866 goto out; 867 868 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { 869 truncate_setsize(inode, ia->ia_size); 870 lower_ia->ia_size = ia->ia_size; 871 lower_ia->ia_valid |= ATTR_SIZE; 872 goto out; 873 } 874 if (num_zeros) { 875 char *zeros_virt; 876 877 zeros_virt = kzalloc(num_zeros, GFP_KERNEL); 878 if (!zeros_virt) { 879 rc = -ENOMEM; 880 goto out; 881 } 882 rc = ecryptfs_write(inode, zeros_virt, 883 ia->ia_size, num_zeros); 884 kfree(zeros_virt); 885 if (rc) { 886 printk(KERN_ERR "Error attempting to zero out " 887 "the remainder of the end page on " 888 "reducing truncate; rc = [%d]\n", rc); 889 goto out; 890 } 891 } 892 truncate_setsize(inode, ia->ia_size); 893 rc = ecryptfs_write_inode_size_to_metadata(inode); 894 if (rc) { 895 printk(KERN_ERR "Problem with " 896 "ecryptfs_write_inode_size_to_metadata; " 897 "rc = [%d]\n", rc); 898 goto out; 899 } 900 /* We are reducing the size of the ecryptfs file, and need to 901 * know if we need to reduce the size of the lower file. */ 902 lower_size_before_truncate = 903 upper_size_to_lower_size(crypt_stat, i_size); 904 lower_size_after_truncate = 905 upper_size_to_lower_size(crypt_stat, ia->ia_size); 906 if (lower_size_after_truncate < lower_size_before_truncate) { 907 lower_ia->ia_size = lower_size_after_truncate; 908 lower_ia->ia_valid |= ATTR_SIZE; 909 } else 910 lower_ia->ia_valid &= ~ATTR_SIZE; 911 } 912 out: 913 ecryptfs_put_lower_file(inode); 914 return rc; 915 } 916 917 /** 918 * ecryptfs_truncate 919 * @dentry: The ecryptfs layer dentry 920 * @new_length: The length to expand the file to 921 * 922 * Simple function that handles the truncation of an eCryptfs inode and 923 * its corresponding lower inode. 924 * 925 * Returns zero on success; non-zero otherwise 926 */ 927 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) 928 { 929 struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length }; 930 struct iattr lower_ia = { .ia_valid = 0 }; 931 int rc; 932 933 rc = truncate_upper(dentry, &ia, &lower_ia); 934 if (!rc && lower_ia.ia_valid & ATTR_SIZE) { 935 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 936 937 mutex_lock(&lower_dentry->d_inode->i_mutex); 938 rc = notify_change(lower_dentry, &lower_ia); 939 mutex_unlock(&lower_dentry->d_inode->i_mutex); 940 } 941 return rc; 942 } 943 944 static int 945 ecryptfs_permission(struct inode *inode, int mask, unsigned int flags) 946 { 947 if (flags & IPERM_FLAG_RCU) 948 return -ECHILD; 949 return inode_permission(ecryptfs_inode_to_lower(inode), mask); 950 } 951 952 /** 953 * ecryptfs_setattr 954 * @dentry: dentry handle to the inode to modify 955 * @ia: Structure with flags of what to change and values 956 * 957 * Updates the metadata of an inode. If the update is to the size 958 * i.e. truncation, then ecryptfs_truncate will handle the size modification 959 * of both the ecryptfs inode and the lower inode. 960 * 961 * All other metadata changes will be passed right to the lower filesystem, 962 * and we will just update our inode to look like the lower. 963 */ 964 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) 965 { 966 int rc = 0; 967 struct dentry *lower_dentry; 968 struct iattr lower_ia; 969 struct inode *inode; 970 struct inode *lower_inode; 971 struct ecryptfs_crypt_stat *crypt_stat; 972 973 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 974 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) 975 ecryptfs_init_crypt_stat(crypt_stat); 976 inode = dentry->d_inode; 977 lower_inode = ecryptfs_inode_to_lower(inode); 978 lower_dentry = ecryptfs_dentry_to_lower(dentry); 979 mutex_lock(&crypt_stat->cs_mutex); 980 if (S_ISDIR(dentry->d_inode->i_mode)) 981 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 982 else if (S_ISREG(dentry->d_inode->i_mode) 983 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) 984 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) { 985 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 986 987 mount_crypt_stat = &ecryptfs_superblock_to_private( 988 dentry->d_sb)->mount_crypt_stat; 989 rc = ecryptfs_get_lower_file(dentry, inode); 990 if (rc) { 991 mutex_unlock(&crypt_stat->cs_mutex); 992 goto out; 993 } 994 rc = ecryptfs_read_metadata(dentry); 995 ecryptfs_put_lower_file(inode); 996 if (rc) { 997 if (!(mount_crypt_stat->flags 998 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { 999 rc = -EIO; 1000 printk(KERN_WARNING "Either the lower file " 1001 "is not in a valid eCryptfs format, " 1002 "or the key could not be retrieved. " 1003 "Plaintext passthrough mode is not " 1004 "enabled; returning -EIO\n"); 1005 mutex_unlock(&crypt_stat->cs_mutex); 1006 goto out; 1007 } 1008 rc = 0; 1009 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED 1010 | ECRYPTFS_ENCRYPTED); 1011 } 1012 } 1013 mutex_unlock(&crypt_stat->cs_mutex); 1014 if (S_ISREG(inode->i_mode)) { 1015 rc = filemap_write_and_wait(inode->i_mapping); 1016 if (rc) 1017 goto out; 1018 fsstack_copy_attr_all(inode, lower_inode); 1019 } 1020 memcpy(&lower_ia, ia, sizeof(lower_ia)); 1021 if (ia->ia_valid & ATTR_FILE) 1022 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file); 1023 if (ia->ia_valid & ATTR_SIZE) { 1024 rc = truncate_upper(dentry, ia, &lower_ia); 1025 if (rc < 0) 1026 goto out; 1027 } 1028 1029 /* 1030 * mode change is for clearing setuid/setgid bits. Allow lower fs 1031 * to interpret this in its own way. 1032 */ 1033 if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) 1034 lower_ia.ia_valid &= ~ATTR_MODE; 1035 1036 mutex_lock(&lower_dentry->d_inode->i_mutex); 1037 rc = notify_change(lower_dentry, &lower_ia); 1038 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1039 out: 1040 fsstack_copy_attr_all(inode, lower_inode); 1041 return rc; 1042 } 1043 1044 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry, 1045 struct kstat *stat) 1046 { 1047 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 1048 int rc = 0; 1049 1050 mount_crypt_stat = &ecryptfs_superblock_to_private( 1051 dentry->d_sb)->mount_crypt_stat; 1052 generic_fillattr(dentry->d_inode, stat); 1053 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { 1054 char *target; 1055 size_t targetsiz; 1056 1057 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz); 1058 if (!rc) { 1059 kfree(target); 1060 stat->size = targetsiz; 1061 } 1062 } 1063 return rc; 1064 } 1065 1066 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry, 1067 struct kstat *stat) 1068 { 1069 struct kstat lower_stat; 1070 int rc; 1071 1072 rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry), 1073 ecryptfs_dentry_to_lower(dentry), &lower_stat); 1074 if (!rc) { 1075 fsstack_copy_attr_all(dentry->d_inode, 1076 ecryptfs_inode_to_lower(dentry->d_inode)); 1077 generic_fillattr(dentry->d_inode, stat); 1078 stat->blocks = lower_stat.blocks; 1079 } 1080 return rc; 1081 } 1082 1083 int 1084 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value, 1085 size_t size, int flags) 1086 { 1087 int rc = 0; 1088 struct dentry *lower_dentry; 1089 1090 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1091 if (!lower_dentry->d_inode->i_op->setxattr) { 1092 rc = -EOPNOTSUPP; 1093 goto out; 1094 } 1095 1096 rc = vfs_setxattr(lower_dentry, name, value, size, flags); 1097 out: 1098 return rc; 1099 } 1100 1101 ssize_t 1102 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name, 1103 void *value, size_t size) 1104 { 1105 int rc = 0; 1106 1107 if (!lower_dentry->d_inode->i_op->getxattr) { 1108 rc = -EOPNOTSUPP; 1109 goto out; 1110 } 1111 mutex_lock(&lower_dentry->d_inode->i_mutex); 1112 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value, 1113 size); 1114 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1115 out: 1116 return rc; 1117 } 1118 1119 static ssize_t 1120 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value, 1121 size_t size) 1122 { 1123 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name, 1124 value, size); 1125 } 1126 1127 static ssize_t 1128 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size) 1129 { 1130 int rc = 0; 1131 struct dentry *lower_dentry; 1132 1133 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1134 if (!lower_dentry->d_inode->i_op->listxattr) { 1135 rc = -EOPNOTSUPP; 1136 goto out; 1137 } 1138 mutex_lock(&lower_dentry->d_inode->i_mutex); 1139 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size); 1140 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1141 out: 1142 return rc; 1143 } 1144 1145 static int ecryptfs_removexattr(struct dentry *dentry, const char *name) 1146 { 1147 int rc = 0; 1148 struct dentry *lower_dentry; 1149 1150 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1151 if (!lower_dentry->d_inode->i_op->removexattr) { 1152 rc = -EOPNOTSUPP; 1153 goto out; 1154 } 1155 mutex_lock(&lower_dentry->d_inode->i_mutex); 1156 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name); 1157 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1158 out: 1159 return rc; 1160 } 1161 1162 const struct inode_operations ecryptfs_symlink_iops = { 1163 .readlink = ecryptfs_readlink, 1164 .follow_link = ecryptfs_follow_link, 1165 .put_link = ecryptfs_put_link, 1166 .permission = ecryptfs_permission, 1167 .setattr = ecryptfs_setattr, 1168 .getattr = ecryptfs_getattr_link, 1169 .setxattr = ecryptfs_setxattr, 1170 .getxattr = ecryptfs_getxattr, 1171 .listxattr = ecryptfs_listxattr, 1172 .removexattr = ecryptfs_removexattr 1173 }; 1174 1175 const struct inode_operations ecryptfs_dir_iops = { 1176 .create = ecryptfs_create, 1177 .lookup = ecryptfs_lookup, 1178 .link = ecryptfs_link, 1179 .unlink = ecryptfs_unlink, 1180 .symlink = ecryptfs_symlink, 1181 .mkdir = ecryptfs_mkdir, 1182 .rmdir = ecryptfs_rmdir, 1183 .mknod = ecryptfs_mknod, 1184 .rename = ecryptfs_rename, 1185 .permission = ecryptfs_permission, 1186 .setattr = ecryptfs_setattr, 1187 .setxattr = ecryptfs_setxattr, 1188 .getxattr = ecryptfs_getxattr, 1189 .listxattr = ecryptfs_listxattr, 1190 .removexattr = ecryptfs_removexattr 1191 }; 1192 1193 const struct inode_operations ecryptfs_main_iops = { 1194 .permission = ecryptfs_permission, 1195 .setattr = ecryptfs_setattr, 1196 .getattr = ecryptfs_getattr, 1197 .setxattr = ecryptfs_setxattr, 1198 .getxattr = ecryptfs_getxattr, 1199 .listxattr = ecryptfs_listxattr, 1200 .removexattr = ecryptfs_removexattr 1201 }; 1202