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