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 "ecryptfs_kernel.h" 35 36 static struct dentry *lock_parent(struct dentry *dentry) 37 { 38 struct dentry *dir; 39 40 dir = dget(dentry->d_parent); 41 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT); 42 return dir; 43 } 44 45 static void unlock_parent(struct dentry *dentry) 46 { 47 mutex_unlock(&(dentry->d_parent->d_inode->i_mutex)); 48 dput(dentry->d_parent); 49 } 50 51 static void unlock_dir(struct dentry *dir) 52 { 53 mutex_unlock(&dir->d_inode->i_mutex); 54 dput(dir); 55 } 56 57 /** 58 * ecryptfs_create_underlying_file 59 * @lower_dir_inode: inode of the parent in the lower fs of the new file 60 * @lower_dentry: New file's dentry in the lower fs 61 * @ecryptfs_dentry: New file's dentry in ecryptfs 62 * @mode: The mode of the new file 63 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount 64 * 65 * Creates the file in the lower file system. 66 * 67 * Returns zero on success; non-zero on error condition 68 */ 69 static int 70 ecryptfs_create_underlying_file(struct inode *lower_dir_inode, 71 struct dentry *dentry, int mode, 72 struct nameidata *nd) 73 { 74 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 75 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry); 76 struct dentry *dentry_save; 77 struct vfsmount *vfsmount_save; 78 int rc; 79 80 dentry_save = nd->dentry; 81 vfsmount_save = nd->mnt; 82 nd->dentry = lower_dentry; 83 nd->mnt = lower_mnt; 84 rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd); 85 nd->dentry = dentry_save; 86 nd->mnt = vfsmount_save; 87 return rc; 88 } 89 90 /** 91 * ecryptfs_do_create 92 * @directory_inode: inode of the new file's dentry's parent in ecryptfs 93 * @ecryptfs_dentry: New file's dentry in ecryptfs 94 * @mode: The mode of the new file 95 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount 96 * 97 * Creates the underlying file and the eCryptfs inode which will link to 98 * it. It will also update the eCryptfs directory inode to mimic the 99 * stat of the lower directory inode. 100 * 101 * Returns zero on success; non-zero on error condition 102 */ 103 static int 104 ecryptfs_do_create(struct inode *directory_inode, 105 struct dentry *ecryptfs_dentry, int mode, 106 struct nameidata *nd) 107 { 108 int rc; 109 struct dentry *lower_dentry; 110 struct dentry *lower_dir_dentry; 111 112 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); 113 lower_dir_dentry = lock_parent(lower_dentry); 114 if (unlikely(IS_ERR(lower_dir_dentry))) { 115 ecryptfs_printk(KERN_ERR, "Error locking directory of " 116 "dentry\n"); 117 rc = PTR_ERR(lower_dir_dentry); 118 goto out; 119 } 120 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode, 121 ecryptfs_dentry, mode, nd); 122 if (rc) { 123 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode; 124 struct ecryptfs_inode_info *inode_info = 125 ecryptfs_inode_to_private(ecryptfs_inode); 126 127 printk(KERN_WARNING "%s: Error creating underlying file; " 128 "rc = [%d]; checking for existing\n", __FUNCTION__, rc); 129 if (inode_info) { 130 mutex_lock(&inode_info->lower_file_mutex); 131 if (!inode_info->lower_file) { 132 mutex_unlock(&inode_info->lower_file_mutex); 133 printk(KERN_ERR "%s: Failure to set underlying " 134 "file; rc = [%d]\n", __FUNCTION__, rc); 135 goto out_lock; 136 } 137 mutex_unlock(&inode_info->lower_file_mutex); 138 } 139 } 140 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry, 141 directory_inode->i_sb, 0); 142 if (rc) { 143 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n"); 144 goto out_lock; 145 } 146 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode); 147 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode); 148 out_lock: 149 unlock_dir(lower_dir_dentry); 150 out: 151 return rc; 152 } 153 154 /** 155 * grow_file 156 * @ecryptfs_dentry: the eCryptfs dentry 157 * 158 * This is the code which will grow the file to its correct size. 159 */ 160 static int grow_file(struct dentry *ecryptfs_dentry) 161 { 162 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode; 163 struct file fake_file; 164 struct ecryptfs_file_info tmp_file_info; 165 char zero_virt[] = { 0x00 }; 166 int rc = 0; 167 168 memset(&fake_file, 0, sizeof(fake_file)); 169 fake_file.f_path.dentry = ecryptfs_dentry; 170 memset(&tmp_file_info, 0, sizeof(tmp_file_info)); 171 ecryptfs_set_file_private(&fake_file, &tmp_file_info); 172 ecryptfs_set_file_lower( 173 &fake_file, 174 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file); 175 rc = ecryptfs_write(&fake_file, zero_virt, 0, 1); 176 i_size_write(ecryptfs_inode, 0); 177 rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode); 178 ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |= 179 ECRYPTFS_NEW_FILE; 180 return rc; 181 } 182 183 /** 184 * ecryptfs_initialize_file 185 * 186 * Cause the file to be changed from a basic empty file to an ecryptfs 187 * file with a header and first data page. 188 * 189 * Returns zero on success 190 */ 191 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry) 192 { 193 struct ecryptfs_crypt_stat *crypt_stat = 194 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; 195 int rc = 0; 196 197 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { 198 ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); 199 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 200 goto out; 201 } 202 crypt_stat->flags |= ECRYPTFS_NEW_FILE; 203 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n"); 204 rc = ecryptfs_new_file_context(ecryptfs_dentry); 205 if (rc) { 206 ecryptfs_printk(KERN_ERR, "Error creating new file " 207 "context; rc = [%d]\n", rc); 208 goto out; 209 } 210 rc = ecryptfs_write_metadata(ecryptfs_dentry); 211 if (rc) { 212 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc); 213 goto out; 214 } 215 rc = grow_file(ecryptfs_dentry); 216 if (rc) 217 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc); 218 out: 219 return rc; 220 } 221 222 /** 223 * ecryptfs_create 224 * @dir: The inode of the directory in which to create the file. 225 * @dentry: The eCryptfs dentry 226 * @mode: The mode of the new file. 227 * @nd: nameidata 228 * 229 * Creates a new file. 230 * 231 * Returns zero on success; non-zero on error condition 232 */ 233 static int 234 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry, 235 int mode, struct nameidata *nd) 236 { 237 int rc; 238 239 /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens 240 * the crypt_stat->lower_file (persistent file) */ 241 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd); 242 if (unlikely(rc)) { 243 ecryptfs_printk(KERN_WARNING, "Failed to create file in" 244 "lower filesystem\n"); 245 goto out; 246 } 247 /* At this point, a file exists on "disk"; we need to make sure 248 * that this on disk file is prepared to be an ecryptfs file */ 249 rc = ecryptfs_initialize_file(ecryptfs_dentry); 250 out: 251 return rc; 252 } 253 254 /** 255 * ecryptfs_lookup 256 * @dir: inode 257 * @dentry: The dentry 258 * @nd: nameidata, may be NULL 259 * 260 * Find a file on disk. If the file does not exist, then we'll add it to the 261 * dentry cache and continue on to read it from the disk. 262 */ 263 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry, 264 struct nameidata *nd) 265 { 266 int rc = 0; 267 struct dentry *lower_dir_dentry; 268 struct dentry *lower_dentry; 269 struct vfsmount *lower_mnt; 270 char *encoded_name; 271 int encoded_namelen; 272 struct ecryptfs_crypt_stat *crypt_stat = NULL; 273 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 274 char *page_virt = NULL; 275 struct inode *lower_inode; 276 u64 file_size; 277 278 lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent); 279 dentry->d_op = &ecryptfs_dops; 280 if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, ".")) 281 || (dentry->d_name.len == 2 282 && !strcmp(dentry->d_name.name, ".."))) { 283 d_drop(dentry); 284 goto out; 285 } 286 encoded_namelen = ecryptfs_encode_filename(crypt_stat, 287 dentry->d_name.name, 288 dentry->d_name.len, 289 &encoded_name); 290 if (encoded_namelen < 0) { 291 rc = encoded_namelen; 292 d_drop(dentry); 293 goto out; 294 } 295 ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen " 296 "= [%d]\n", encoded_name, encoded_namelen); 297 lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry, 298 encoded_namelen - 1); 299 kfree(encoded_name); 300 if (IS_ERR(lower_dentry)) { 301 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n"); 302 rc = PTR_ERR(lower_dentry); 303 d_drop(dentry); 304 goto out; 305 } 306 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent)); 307 ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->" 308 "d_name.name = [%s]\n", lower_dentry, 309 lower_dentry->d_name.name); 310 lower_inode = lower_dentry->d_inode; 311 fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode); 312 BUG_ON(!atomic_read(&lower_dentry->d_count)); 313 ecryptfs_set_dentry_private(dentry, 314 kmem_cache_alloc(ecryptfs_dentry_info_cache, 315 GFP_KERNEL)); 316 if (!ecryptfs_dentry_to_private(dentry)) { 317 rc = -ENOMEM; 318 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting " 319 "to allocate ecryptfs_dentry_info struct\n"); 320 goto out_dput; 321 } 322 ecryptfs_set_dentry_lower(dentry, lower_dentry); 323 ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt); 324 if (!lower_dentry->d_inode) { 325 /* We want to add because we couldn't find in lower */ 326 d_add(dentry, NULL); 327 goto out; 328 } 329 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1); 330 if (rc) { 331 ecryptfs_printk(KERN_ERR, "Error interposing\n"); 332 goto out_dput; 333 } 334 if (S_ISDIR(lower_inode->i_mode)) { 335 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n"); 336 goto out; 337 } 338 if (S_ISLNK(lower_inode->i_mode)) { 339 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n"); 340 goto out; 341 } 342 if (special_file(lower_inode->i_mode)) { 343 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n"); 344 goto out; 345 } 346 if (!nd) { 347 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave" 348 "as we *think* we are about to unlink\n"); 349 goto out; 350 } 351 /* Released in this function */ 352 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, 353 GFP_USER); 354 if (!page_virt) { 355 rc = -ENOMEM; 356 ecryptfs_printk(KERN_ERR, 357 "Cannot ecryptfs_kmalloc a page\n"); 358 goto out_dput; 359 } 360 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 361 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) 362 ecryptfs_set_default_sizes(crypt_stat); 363 rc = ecryptfs_read_and_validate_header_region(page_virt, 364 dentry->d_inode); 365 if (rc) { 366 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry); 367 if (rc) { 368 printk(KERN_DEBUG "Valid metadata not found in header " 369 "region or xattr region; treating file as " 370 "unencrypted\n"); 371 rc = 0; 372 kmem_cache_free(ecryptfs_header_cache_2, page_virt); 373 goto out; 374 } 375 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; 376 } 377 mount_crypt_stat = &ecryptfs_superblock_to_private( 378 dentry->d_sb)->mount_crypt_stat; 379 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { 380 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) 381 file_size = ((crypt_stat->extent_size 382 * crypt_stat->num_header_extents_at_front) 383 + i_size_read(lower_dentry->d_inode)); 384 else 385 file_size = i_size_read(lower_dentry->d_inode); 386 } else { 387 memcpy(&file_size, page_virt, sizeof(file_size)); 388 file_size = be64_to_cpu(file_size); 389 } 390 i_size_write(dentry->d_inode, (loff_t)file_size); 391 kmem_cache_free(ecryptfs_header_cache_2, page_virt); 392 goto out; 393 394 out_dput: 395 dput(lower_dentry); 396 d_drop(dentry); 397 out: 398 return ERR_PTR(rc); 399 } 400 401 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir, 402 struct dentry *new_dentry) 403 { 404 struct dentry *lower_old_dentry; 405 struct dentry *lower_new_dentry; 406 struct dentry *lower_dir_dentry; 407 u64 file_size_save; 408 int rc; 409 410 file_size_save = i_size_read(old_dentry->d_inode); 411 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 412 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 413 dget(lower_old_dentry); 414 dget(lower_new_dentry); 415 lower_dir_dentry = lock_parent(lower_new_dentry); 416 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode, 417 lower_new_dentry); 418 if (rc || !lower_new_dentry->d_inode) 419 goto out_lock; 420 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0); 421 if (rc) 422 goto out_lock; 423 fsstack_copy_attr_times(dir, lower_new_dentry->d_inode); 424 fsstack_copy_inode_size(dir, lower_new_dentry->d_inode); 425 old_dentry->d_inode->i_nlink = 426 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink; 427 i_size_write(new_dentry->d_inode, file_size_save); 428 out_lock: 429 unlock_dir(lower_dir_dentry); 430 dput(lower_new_dentry); 431 dput(lower_old_dentry); 432 d_drop(lower_old_dentry); 433 d_drop(new_dentry); 434 d_drop(old_dentry); 435 return rc; 436 } 437 438 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) 439 { 440 int rc = 0; 441 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 442 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); 443 444 lock_parent(lower_dentry); 445 rc = vfs_unlink(lower_dir_inode, lower_dentry); 446 if (rc) { 447 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); 448 goto out_unlock; 449 } 450 fsstack_copy_attr_times(dir, lower_dir_inode); 451 dentry->d_inode->i_nlink = 452 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink; 453 dentry->d_inode->i_ctime = dir->i_ctime; 454 out_unlock: 455 unlock_parent(lower_dentry); 456 return rc; 457 } 458 459 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry, 460 const char *symname) 461 { 462 int rc; 463 struct dentry *lower_dentry; 464 struct dentry *lower_dir_dentry; 465 umode_t mode; 466 char *encoded_symname; 467 int encoded_symlen; 468 struct ecryptfs_crypt_stat *crypt_stat = NULL; 469 470 lower_dentry = ecryptfs_dentry_to_lower(dentry); 471 dget(lower_dentry); 472 lower_dir_dentry = lock_parent(lower_dentry); 473 mode = S_IALLUGO; 474 encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname, 475 strlen(symname), 476 &encoded_symname); 477 if (encoded_symlen < 0) { 478 rc = encoded_symlen; 479 goto out_lock; 480 } 481 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry, 482 encoded_symname, mode); 483 kfree(encoded_symname); 484 if (rc || !lower_dentry->d_inode) 485 goto out_lock; 486 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 487 if (rc) 488 goto out_lock; 489 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 490 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 491 out_lock: 492 unlock_dir(lower_dir_dentry); 493 dput(lower_dentry); 494 if (!dentry->d_inode) 495 d_drop(dentry); 496 return rc; 497 } 498 499 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 500 { 501 int rc; 502 struct dentry *lower_dentry; 503 struct dentry *lower_dir_dentry; 504 505 lower_dentry = ecryptfs_dentry_to_lower(dentry); 506 lower_dir_dentry = lock_parent(lower_dentry); 507 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode); 508 if (rc || !lower_dentry->d_inode) 509 goto out; 510 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 511 if (rc) 512 goto out; 513 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 514 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 515 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 516 out: 517 unlock_dir(lower_dir_dentry); 518 if (!dentry->d_inode) 519 d_drop(dentry); 520 return rc; 521 } 522 523 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) 524 { 525 struct dentry *lower_dentry; 526 struct dentry *lower_dir_dentry; 527 int rc; 528 529 lower_dentry = ecryptfs_dentry_to_lower(dentry); 530 dget(dentry); 531 lower_dir_dentry = lock_parent(lower_dentry); 532 dget(lower_dentry); 533 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry); 534 dput(lower_dentry); 535 if (!rc) 536 d_delete(lower_dentry); 537 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 538 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 539 unlock_dir(lower_dir_dentry); 540 if (!rc) 541 d_drop(dentry); 542 dput(dentry); 543 return rc; 544 } 545 546 static int 547 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 548 { 549 int rc; 550 struct dentry *lower_dentry; 551 struct dentry *lower_dir_dentry; 552 553 lower_dentry = ecryptfs_dentry_to_lower(dentry); 554 lower_dir_dentry = lock_parent(lower_dentry); 555 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); 556 if (rc || !lower_dentry->d_inode) 557 goto out; 558 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 559 if (rc) 560 goto out; 561 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 562 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 563 out: 564 unlock_dir(lower_dir_dentry); 565 if (!dentry->d_inode) 566 d_drop(dentry); 567 return rc; 568 } 569 570 static int 571 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, 572 struct inode *new_dir, struct dentry *new_dentry) 573 { 574 int rc; 575 struct dentry *lower_old_dentry; 576 struct dentry *lower_new_dentry; 577 struct dentry *lower_old_dir_dentry; 578 struct dentry *lower_new_dir_dentry; 579 580 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 581 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 582 dget(lower_old_dentry); 583 dget(lower_new_dentry); 584 lower_old_dir_dentry = dget_parent(lower_old_dentry); 585 lower_new_dir_dentry = dget_parent(lower_new_dentry); 586 lock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 587 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry, 588 lower_new_dir_dentry->d_inode, lower_new_dentry); 589 if (rc) 590 goto out_lock; 591 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL); 592 if (new_dir != old_dir) 593 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL); 594 out_lock: 595 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 596 dput(lower_new_dentry->d_parent); 597 dput(lower_old_dentry->d_parent); 598 dput(lower_new_dentry); 599 dput(lower_old_dentry); 600 return rc; 601 } 602 603 static int 604 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz) 605 { 606 int rc; 607 struct dentry *lower_dentry; 608 char *decoded_name; 609 char *lower_buf; 610 mm_segment_t old_fs; 611 struct ecryptfs_crypt_stat *crypt_stat; 612 613 lower_dentry = ecryptfs_dentry_to_lower(dentry); 614 if (!lower_dentry->d_inode->i_op || 615 !lower_dentry->d_inode->i_op->readlink) { 616 rc = -EINVAL; 617 goto out; 618 } 619 /* Released in this function */ 620 lower_buf = kmalloc(bufsiz, GFP_KERNEL); 621 if (lower_buf == NULL) { 622 ecryptfs_printk(KERN_ERR, "Out of memory\n"); 623 rc = -ENOMEM; 624 goto out; 625 } 626 old_fs = get_fs(); 627 set_fs(get_ds()); 628 ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ " 629 "lower_dentry->d_name.name = [%s]\n", 630 lower_dentry->d_name.name); 631 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry, 632 (char __user *)lower_buf, 633 bufsiz); 634 set_fs(old_fs); 635 if (rc >= 0) { 636 crypt_stat = NULL; 637 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc, 638 &decoded_name); 639 if (rc == -ENOMEM) 640 goto out_free_lower_buf; 641 if (rc > 0) { 642 ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes " 643 "to userspace: [%*s]\n", rc, 644 decoded_name); 645 if (copy_to_user(buf, decoded_name, rc)) 646 rc = -EFAULT; 647 } 648 kfree(decoded_name); 649 fsstack_copy_attr_atime(dentry->d_inode, 650 lower_dentry->d_inode); 651 } 652 out_free_lower_buf: 653 kfree(lower_buf); 654 out: 655 return rc; 656 } 657 658 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd) 659 { 660 char *buf; 661 int len = PAGE_SIZE, rc; 662 mm_segment_t old_fs; 663 664 /* Released in ecryptfs_put_link(); only release here on error */ 665 buf = kmalloc(len, GFP_KERNEL); 666 if (!buf) { 667 rc = -ENOMEM; 668 goto out; 669 } 670 old_fs = get_fs(); 671 set_fs(get_ds()); 672 ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ " 673 "dentry->d_name.name = [%s]\n", dentry->d_name.name); 674 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len); 675 buf[rc] = '\0'; 676 set_fs(old_fs); 677 if (rc < 0) 678 goto out_free; 679 rc = 0; 680 nd_set_link(nd, buf); 681 goto out; 682 out_free: 683 kfree(buf); 684 out: 685 return ERR_PTR(rc); 686 } 687 688 static void 689 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr) 690 { 691 /* Free the char* */ 692 kfree(nd_get_link(nd)); 693 } 694 695 /** 696 * upper_size_to_lower_size 697 * @crypt_stat: Crypt_stat associated with file 698 * @upper_size: Size of the upper file 699 * 700 * Calculate the requried size of the lower file based on the 701 * specified size of the upper file. This calculation is based on the 702 * number of headers in the underlying file and the extent size. 703 * 704 * Returns Calculated size of the lower file. 705 */ 706 static loff_t 707 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, 708 loff_t upper_size) 709 { 710 loff_t lower_size; 711 712 lower_size = (crypt_stat->extent_size 713 * crypt_stat->num_header_extents_at_front); 714 if (upper_size != 0) { 715 loff_t num_extents; 716 717 num_extents = upper_size >> crypt_stat->extent_shift; 718 if (upper_size & ~crypt_stat->extent_mask) 719 num_extents++; 720 lower_size += (num_extents * crypt_stat->extent_size); 721 } 722 return lower_size; 723 } 724 725 /** 726 * ecryptfs_truncate 727 * @dentry: The ecryptfs layer dentry 728 * @new_length: The length to expand the file to 729 * 730 * Function to handle truncations modifying the size of the file. Note 731 * that the file sizes are interpolated. When expanding, we are simply 732 * writing strings of 0's out. When truncating, we need to modify the 733 * underlying file size according to the page index interpolations. 734 * 735 * Returns zero on success; non-zero otherwise 736 */ 737 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) 738 { 739 int rc = 0; 740 struct inode *inode = dentry->d_inode; 741 struct dentry *lower_dentry; 742 struct file fake_ecryptfs_file; 743 struct ecryptfs_crypt_stat *crypt_stat; 744 loff_t i_size = i_size_read(inode); 745 loff_t lower_size_before_truncate; 746 loff_t lower_size_after_truncate; 747 748 if (unlikely((new_length == i_size))) 749 goto out; 750 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 751 /* Set up a fake ecryptfs file, this is used to interface with 752 * the file in the underlying filesystem so that the 753 * truncation has an effect there as well. */ 754 memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file)); 755 fake_ecryptfs_file.f_path.dentry = dentry; 756 /* Released at out_free: label */ 757 ecryptfs_set_file_private(&fake_ecryptfs_file, 758 kmem_cache_alloc(ecryptfs_file_info_cache, 759 GFP_KERNEL)); 760 if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) { 761 rc = -ENOMEM; 762 goto out; 763 } 764 lower_dentry = ecryptfs_dentry_to_lower(dentry); 765 ecryptfs_set_file_lower( 766 &fake_ecryptfs_file, 767 ecryptfs_inode_to_private(dentry->d_inode)->lower_file); 768 /* Switch on growing or shrinking file */ 769 if (new_length > i_size) { 770 char zero[] = { 0x00 }; 771 772 /* Write a single 0 at the last position of the file; 773 * this triggers code that will fill in 0's throughout 774 * the intermediate portion of the previous end of the 775 * file and the new and of the file */ 776 rc = ecryptfs_write(&fake_ecryptfs_file, zero, 777 (new_length - 1), 1); 778 } else { /* new_length < i_size_read(inode) */ 779 /* We're chopping off all the pages down do the page 780 * in which new_length is located. Fill in the end of 781 * that page from (new_length & ~PAGE_CACHE_MASK) to 782 * PAGE_CACHE_SIZE with zeros. */ 783 size_t num_zeros = (PAGE_CACHE_SIZE 784 - (new_length & ~PAGE_CACHE_MASK)); 785 786 if (num_zeros) { 787 char *zeros_virt; 788 789 zeros_virt = kzalloc(num_zeros, GFP_KERNEL); 790 if (!zeros_virt) { 791 rc = -ENOMEM; 792 goto out_free; 793 } 794 rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt, 795 new_length, num_zeros); 796 kfree(zeros_virt); 797 if (rc) { 798 printk(KERN_ERR "Error attempting to zero out " 799 "the remainder of the end page on " 800 "reducing truncate; rc = [%d]\n", rc); 801 goto out_free; 802 } 803 } 804 vmtruncate(inode, new_length); 805 rc = ecryptfs_write_inode_size_to_metadata(inode); 806 if (rc) { 807 printk(KERN_ERR "Problem with " 808 "ecryptfs_write_inode_size_to_metadata; " 809 "rc = [%d]\n", rc); 810 goto out_free; 811 } 812 /* We are reducing the size of the ecryptfs file, and need to 813 * know if we need to reduce the size of the lower file. */ 814 lower_size_before_truncate = 815 upper_size_to_lower_size(crypt_stat, i_size); 816 lower_size_after_truncate = 817 upper_size_to_lower_size(crypt_stat, new_length); 818 if (lower_size_after_truncate < lower_size_before_truncate) 819 vmtruncate(lower_dentry->d_inode, 820 lower_size_after_truncate); 821 } 822 out_free: 823 if (ecryptfs_file_to_private(&fake_ecryptfs_file)) 824 kmem_cache_free(ecryptfs_file_info_cache, 825 ecryptfs_file_to_private(&fake_ecryptfs_file)); 826 out: 827 return rc; 828 } 829 830 static int 831 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd) 832 { 833 int rc; 834 835 if (nd) { 836 struct vfsmount *vfsmnt_save = nd->mnt; 837 struct dentry *dentry_save = nd->dentry; 838 839 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry); 840 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry); 841 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd); 842 nd->mnt = vfsmnt_save; 843 nd->dentry = dentry_save; 844 } else 845 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL); 846 return rc; 847 } 848 849 /** 850 * ecryptfs_setattr 851 * @dentry: dentry handle to the inode to modify 852 * @ia: Structure with flags of what to change and values 853 * 854 * Updates the metadata of an inode. If the update is to the size 855 * i.e. truncation, then ecryptfs_truncate will handle the size modification 856 * of both the ecryptfs inode and the lower inode. 857 * 858 * All other metadata changes will be passed right to the lower filesystem, 859 * and we will just update our inode to look like the lower. 860 */ 861 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) 862 { 863 int rc = 0; 864 struct dentry *lower_dentry; 865 struct inode *inode; 866 struct inode *lower_inode; 867 struct ecryptfs_crypt_stat *crypt_stat; 868 869 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 870 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) 871 ecryptfs_init_crypt_stat(crypt_stat); 872 inode = dentry->d_inode; 873 lower_inode = ecryptfs_inode_to_lower(inode); 874 lower_dentry = ecryptfs_dentry_to_lower(dentry); 875 mutex_lock(&crypt_stat->cs_mutex); 876 if (S_ISDIR(dentry->d_inode->i_mode)) 877 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 878 else if (S_ISREG(dentry->d_inode->i_mode) 879 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) 880 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) { 881 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 882 883 mount_crypt_stat = &ecryptfs_superblock_to_private( 884 dentry->d_sb)->mount_crypt_stat; 885 rc = ecryptfs_read_metadata(dentry); 886 if (rc) { 887 if (!(mount_crypt_stat->flags 888 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { 889 rc = -EIO; 890 printk(KERN_WARNING "Attempt to read file that " 891 "is not in a valid eCryptfs format, " 892 "and plaintext passthrough mode is not " 893 "enabled; returning -EIO\n"); 894 895 mutex_unlock(&crypt_stat->cs_mutex); 896 goto out; 897 } 898 rc = 0; 899 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 900 mutex_unlock(&crypt_stat->cs_mutex); 901 goto out; 902 } 903 } 904 mutex_unlock(&crypt_stat->cs_mutex); 905 if (ia->ia_valid & ATTR_SIZE) { 906 ecryptfs_printk(KERN_DEBUG, 907 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n", 908 ia->ia_valid, ATTR_SIZE); 909 rc = ecryptfs_truncate(dentry, ia->ia_size); 910 /* ecryptfs_truncate handles resizing of the lower file */ 911 ia->ia_valid &= ~ATTR_SIZE; 912 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n", 913 ia->ia_valid); 914 if (rc < 0) 915 goto out; 916 } 917 rc = notify_change(lower_dentry, ia); 918 out: 919 fsstack_copy_attr_all(inode, lower_inode, NULL); 920 return rc; 921 } 922 923 int 924 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value, 925 size_t size, int flags) 926 { 927 int rc = 0; 928 struct dentry *lower_dentry; 929 930 lower_dentry = ecryptfs_dentry_to_lower(dentry); 931 if (!lower_dentry->d_inode->i_op->setxattr) { 932 rc = -ENOSYS; 933 goto out; 934 } 935 mutex_lock(&lower_dentry->d_inode->i_mutex); 936 rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value, 937 size, flags); 938 mutex_unlock(&lower_dentry->d_inode->i_mutex); 939 out: 940 return rc; 941 } 942 943 ssize_t 944 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name, 945 void *value, size_t size) 946 { 947 int rc = 0; 948 949 if (!lower_dentry->d_inode->i_op->getxattr) { 950 rc = -ENOSYS; 951 goto out; 952 } 953 mutex_lock(&lower_dentry->d_inode->i_mutex); 954 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value, 955 size); 956 mutex_unlock(&lower_dentry->d_inode->i_mutex); 957 out: 958 return rc; 959 } 960 961 ssize_t 962 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value, 963 size_t size) 964 { 965 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name, 966 value, size); 967 } 968 969 static ssize_t 970 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size) 971 { 972 int rc = 0; 973 struct dentry *lower_dentry; 974 975 lower_dentry = ecryptfs_dentry_to_lower(dentry); 976 if (!lower_dentry->d_inode->i_op->listxattr) { 977 rc = -ENOSYS; 978 goto out; 979 } 980 mutex_lock(&lower_dentry->d_inode->i_mutex); 981 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size); 982 mutex_unlock(&lower_dentry->d_inode->i_mutex); 983 out: 984 return rc; 985 } 986 987 static int ecryptfs_removexattr(struct dentry *dentry, const char *name) 988 { 989 int rc = 0; 990 struct dentry *lower_dentry; 991 992 lower_dentry = ecryptfs_dentry_to_lower(dentry); 993 if (!lower_dentry->d_inode->i_op->removexattr) { 994 rc = -ENOSYS; 995 goto out; 996 } 997 mutex_lock(&lower_dentry->d_inode->i_mutex); 998 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name); 999 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1000 out: 1001 return rc; 1002 } 1003 1004 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode) 1005 { 1006 if ((ecryptfs_inode_to_lower(inode) 1007 == (struct inode *)candidate_lower_inode)) 1008 return 1; 1009 else 1010 return 0; 1011 } 1012 1013 int ecryptfs_inode_set(struct inode *inode, void *lower_inode) 1014 { 1015 ecryptfs_init_inode(inode, (struct inode *)lower_inode); 1016 return 0; 1017 } 1018 1019 const struct inode_operations ecryptfs_symlink_iops = { 1020 .readlink = ecryptfs_readlink, 1021 .follow_link = ecryptfs_follow_link, 1022 .put_link = ecryptfs_put_link, 1023 .permission = ecryptfs_permission, 1024 .setattr = ecryptfs_setattr, 1025 .setxattr = ecryptfs_setxattr, 1026 .getxattr = ecryptfs_getxattr, 1027 .listxattr = ecryptfs_listxattr, 1028 .removexattr = ecryptfs_removexattr 1029 }; 1030 1031 const struct inode_operations ecryptfs_dir_iops = { 1032 .create = ecryptfs_create, 1033 .lookup = ecryptfs_lookup, 1034 .link = ecryptfs_link, 1035 .unlink = ecryptfs_unlink, 1036 .symlink = ecryptfs_symlink, 1037 .mkdir = ecryptfs_mkdir, 1038 .rmdir = ecryptfs_rmdir, 1039 .mknod = ecryptfs_mknod, 1040 .rename = ecryptfs_rename, 1041 .permission = ecryptfs_permission, 1042 .setattr = ecryptfs_setattr, 1043 .setxattr = ecryptfs_setxattr, 1044 .getxattr = ecryptfs_getxattr, 1045 .listxattr = ecryptfs_listxattr, 1046 .removexattr = ecryptfs_removexattr 1047 }; 1048 1049 const struct inode_operations ecryptfs_main_iops = { 1050 .permission = ecryptfs_permission, 1051 .setattr = ecryptfs_setattr, 1052 .setxattr = ecryptfs_setxattr, 1053 .getxattr = ecryptfs_getxattr, 1054 .listxattr = ecryptfs_listxattr, 1055 .removexattr = ecryptfs_removexattr 1056 }; 1057