1 /** 2 * eCryptfs: Linux filesystem encryption layer 3 * 4 * Copyright (C) 1997-2004 Erez Zadok 5 * Copyright (C) 2001-2004 Stony Brook University 6 * Copyright (C) 2004-2007 International Business Machines Corp. 7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> 8 * Michael C. Thompsion <mcthomps@us.ibm.com> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation; either version 2 of the 13 * License, or (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, but 16 * WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 23 * 02111-1307, USA. 24 */ 25 26 #include <linux/file.h> 27 #include <linux/vmalloc.h> 28 #include <linux/pagemap.h> 29 #include <linux/dcache.h> 30 #include <linux/namei.h> 31 #include <linux/mount.h> 32 #include <linux/crypto.h> 33 #include <linux/fs_stack.h> 34 #include <asm/unaligned.h> 35 #include "ecryptfs_kernel.h" 36 37 static struct dentry *lock_parent(struct dentry *dentry) 38 { 39 struct dentry *dir; 40 41 dir = dget_parent(dentry); 42 mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT); 43 return dir; 44 } 45 46 static void unlock_dir(struct dentry *dir) 47 { 48 mutex_unlock(&dir->d_inode->i_mutex); 49 dput(dir); 50 } 51 52 /** 53 * ecryptfs_create_underlying_file 54 * @lower_dir_inode: inode of the parent in the lower fs of the new file 55 * @dentry: New file's dentry 56 * @mode: The mode of the new file 57 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount 58 * 59 * Creates the file in the lower file system. 60 * 61 * Returns zero on success; non-zero on error condition 62 */ 63 static int 64 ecryptfs_create_underlying_file(struct inode *lower_dir_inode, 65 struct dentry *dentry, int mode, 66 struct nameidata *nd) 67 { 68 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 69 struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry); 70 struct dentry *dentry_save; 71 struct vfsmount *vfsmount_save; 72 int rc; 73 74 dentry_save = nd->path.dentry; 75 vfsmount_save = nd->path.mnt; 76 nd->path.dentry = lower_dentry; 77 nd->path.mnt = lower_mnt; 78 rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd); 79 nd->path.dentry = dentry_save; 80 nd->path.mnt = vfsmount_save; 81 return rc; 82 } 83 84 /** 85 * ecryptfs_do_create 86 * @directory_inode: inode of the new file's dentry's parent in ecryptfs 87 * @ecryptfs_dentry: New file's dentry in ecryptfs 88 * @mode: The mode of the new file 89 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount 90 * 91 * Creates the underlying file and the eCryptfs inode which will link to 92 * it. It will also update the eCryptfs directory inode to mimic the 93 * stat of the lower directory inode. 94 * 95 * Returns zero on success; non-zero on error condition 96 */ 97 static int 98 ecryptfs_do_create(struct inode *directory_inode, 99 struct dentry *ecryptfs_dentry, int mode, 100 struct nameidata *nd) 101 { 102 int rc; 103 struct dentry *lower_dentry; 104 struct dentry *lower_dir_dentry; 105 106 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); 107 lower_dir_dentry = lock_parent(lower_dentry); 108 if (IS_ERR(lower_dir_dentry)) { 109 ecryptfs_printk(KERN_ERR, "Error locking directory of " 110 "dentry\n"); 111 rc = PTR_ERR(lower_dir_dentry); 112 goto out; 113 } 114 rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode, 115 ecryptfs_dentry, mode, nd); 116 if (rc) { 117 printk(KERN_ERR "%s: Failure to create dentry in lower fs; " 118 "rc = [%d]\n", __func__, rc); 119 goto out_lock; 120 } 121 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry, 122 directory_inode->i_sb, 0); 123 if (rc) { 124 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n"); 125 goto out_lock; 126 } 127 fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode); 128 fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode); 129 out_lock: 130 unlock_dir(lower_dir_dentry); 131 out: 132 return rc; 133 } 134 135 /** 136 * grow_file 137 * @ecryptfs_dentry: the eCryptfs dentry 138 * 139 * This is the code which will grow the file to its correct size. 140 */ 141 static int grow_file(struct dentry *ecryptfs_dentry) 142 { 143 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode; 144 struct file fake_file; 145 struct ecryptfs_file_info tmp_file_info; 146 char zero_virt[] = { 0x00 }; 147 int rc = 0; 148 149 memset(&fake_file, 0, sizeof(fake_file)); 150 fake_file.f_path.dentry = ecryptfs_dentry; 151 memset(&tmp_file_info, 0, sizeof(tmp_file_info)); 152 ecryptfs_set_file_private(&fake_file, &tmp_file_info); 153 ecryptfs_set_file_lower( 154 &fake_file, 155 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file); 156 rc = ecryptfs_write(&fake_file, zero_virt, 0, 1); 157 i_size_write(ecryptfs_inode, 0); 158 rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode); 159 ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |= 160 ECRYPTFS_NEW_FILE; 161 return rc; 162 } 163 164 /** 165 * ecryptfs_initialize_file 166 * 167 * Cause the file to be changed from a basic empty file to an ecryptfs 168 * file with a header and first data page. 169 * 170 * Returns zero on success 171 */ 172 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry) 173 { 174 struct ecryptfs_crypt_stat *crypt_stat = 175 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; 176 int rc = 0; 177 178 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { 179 ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); 180 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 181 goto out; 182 } 183 crypt_stat->flags |= ECRYPTFS_NEW_FILE; 184 ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n"); 185 rc = ecryptfs_new_file_context(ecryptfs_dentry); 186 if (rc) { 187 ecryptfs_printk(KERN_ERR, "Error creating new file " 188 "context; rc = [%d]\n", rc); 189 goto out; 190 } 191 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) { 192 rc = ecryptfs_init_persistent_file(ecryptfs_dentry); 193 if (rc) { 194 printk(KERN_ERR "%s: Error attempting to initialize " 195 "the persistent file for the dentry with name " 196 "[%s]; rc = [%d]\n", __func__, 197 ecryptfs_dentry->d_name.name, rc); 198 goto out; 199 } 200 } 201 rc = ecryptfs_write_metadata(ecryptfs_dentry); 202 if (rc) { 203 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc); 204 goto out; 205 } 206 rc = grow_file(ecryptfs_dentry); 207 if (rc) 208 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc); 209 out: 210 return rc; 211 } 212 213 /** 214 * ecryptfs_create 215 * @dir: The inode of the directory in which to create the file. 216 * @dentry: The eCryptfs dentry 217 * @mode: The mode of the new file. 218 * @nd: nameidata 219 * 220 * Creates a new file. 221 * 222 * Returns zero on success; non-zero on error condition 223 */ 224 static int 225 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry, 226 int mode, struct nameidata *nd) 227 { 228 int rc; 229 230 /* ecryptfs_do_create() calls ecryptfs_interpose() */ 231 rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd); 232 if (unlikely(rc)) { 233 ecryptfs_printk(KERN_WARNING, "Failed to create file in" 234 "lower filesystem\n"); 235 goto out; 236 } 237 /* At this point, a file exists on "disk"; we need to make sure 238 * that this on disk file is prepared to be an ecryptfs file */ 239 rc = ecryptfs_initialize_file(ecryptfs_dentry); 240 out: 241 return rc; 242 } 243 244 /** 245 * ecryptfs_lookup_and_interpose_lower - Perform a lookup 246 */ 247 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry, 248 struct dentry *lower_dentry, 249 struct ecryptfs_crypt_stat *crypt_stat, 250 struct inode *ecryptfs_dir_inode, 251 struct nameidata *ecryptfs_nd) 252 { 253 struct dentry *lower_dir_dentry; 254 struct vfsmount *lower_mnt; 255 struct inode *lower_inode; 256 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 257 char *page_virt = NULL; 258 u64 file_size; 259 int rc = 0; 260 261 lower_dir_dentry = lower_dentry->d_parent; 262 lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt( 263 ecryptfs_dentry->d_parent)); 264 lower_inode = lower_dentry->d_inode; 265 fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode); 266 BUG_ON(!atomic_read(&lower_dentry->d_count)); 267 ecryptfs_set_dentry_private(ecryptfs_dentry, 268 kmem_cache_alloc(ecryptfs_dentry_info_cache, 269 GFP_KERNEL)); 270 if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) { 271 rc = -ENOMEM; 272 printk(KERN_ERR "%s: Out of memory whilst attempting " 273 "to allocate ecryptfs_dentry_info struct\n", 274 __func__); 275 goto out_dput; 276 } 277 ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry); 278 ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt); 279 if (!lower_dentry->d_inode) { 280 /* We want to add because we couldn't find in lower */ 281 d_add(ecryptfs_dentry, NULL); 282 goto out; 283 } 284 rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry, 285 ecryptfs_dir_inode->i_sb, 1); 286 if (rc) { 287 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n", 288 __func__, rc); 289 goto out; 290 } 291 if (S_ISDIR(lower_inode->i_mode)) 292 goto out; 293 if (S_ISLNK(lower_inode->i_mode)) 294 goto out; 295 if (special_file(lower_inode->i_mode)) 296 goto out; 297 if (!ecryptfs_nd) 298 goto out; 299 /* Released in this function */ 300 page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER); 301 if (!page_virt) { 302 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n", 303 __func__); 304 rc = -ENOMEM; 305 goto out; 306 } 307 if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) { 308 rc = ecryptfs_init_persistent_file(ecryptfs_dentry); 309 if (rc) { 310 printk(KERN_ERR "%s: Error attempting to initialize " 311 "the persistent file for the dentry with name " 312 "[%s]; rc = [%d]\n", __func__, 313 ecryptfs_dentry->d_name.name, rc); 314 goto out_free_kmem; 315 } 316 } 317 rc = ecryptfs_read_and_validate_header_region(page_virt, 318 ecryptfs_dentry->d_inode); 319 if (rc) { 320 rc = ecryptfs_read_and_validate_xattr_region(page_virt, 321 ecryptfs_dentry); 322 if (rc) { 323 rc = 0; 324 goto out_free_kmem; 325 } 326 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; 327 } 328 mount_crypt_stat = &ecryptfs_superblock_to_private( 329 ecryptfs_dentry->d_sb)->mount_crypt_stat; 330 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { 331 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) 332 file_size = (crypt_stat->num_header_bytes_at_front 333 + i_size_read(lower_dentry->d_inode)); 334 else 335 file_size = i_size_read(lower_dentry->d_inode); 336 } else { 337 file_size = get_unaligned_be64(page_virt); 338 } 339 i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size); 340 out_free_kmem: 341 kmem_cache_free(ecryptfs_header_cache_2, page_virt); 342 goto out; 343 out_dput: 344 dput(lower_dentry); 345 d_drop(ecryptfs_dentry); 346 out: 347 return rc; 348 } 349 350 /** 351 * ecryptfs_lookup 352 * @ecryptfs_dir_inode: The eCryptfs directory inode 353 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up 354 * @ecryptfs_nd: nameidata; may be NULL 355 * 356 * Find a file on disk. If the file does not exist, then we'll add it to the 357 * dentry cache and continue on to read it from the disk. 358 */ 359 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode, 360 struct dentry *ecryptfs_dentry, 361 struct nameidata *ecryptfs_nd) 362 { 363 char *encrypted_and_encoded_name = NULL; 364 size_t encrypted_and_encoded_name_size; 365 struct ecryptfs_crypt_stat *crypt_stat = NULL; 366 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 367 struct ecryptfs_inode_info *inode_info; 368 struct dentry *lower_dir_dentry, *lower_dentry; 369 int rc = 0; 370 371 ecryptfs_dentry->d_op = &ecryptfs_dops; 372 if ((ecryptfs_dentry->d_name.len == 1 373 && !strcmp(ecryptfs_dentry->d_name.name, ".")) 374 || (ecryptfs_dentry->d_name.len == 2 375 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) { 376 goto out_d_drop; 377 } 378 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent); 379 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name, 380 lower_dir_dentry, 381 ecryptfs_dentry->d_name.len); 382 if (IS_ERR(lower_dentry)) { 383 rc = PTR_ERR(lower_dentry); 384 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on " 385 "lower_dentry = [%s]\n", __func__, rc, 386 ecryptfs_dentry->d_name.name); 387 goto out_d_drop; 388 } 389 if (lower_dentry->d_inode) 390 goto lookup_and_interpose; 391 inode_info = ecryptfs_inode_to_private(ecryptfs_dentry->d_inode); 392 if (inode_info) { 393 crypt_stat = &inode_info->crypt_stat; 394 /* TODO: lock for crypt_stat comparison */ 395 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) 396 ecryptfs_set_default_sizes(crypt_stat); 397 } 398 if (crypt_stat) 399 mount_crypt_stat = crypt_stat->mount_crypt_stat; 400 else 401 mount_crypt_stat = &ecryptfs_superblock_to_private( 402 ecryptfs_dentry->d_sb)->mount_crypt_stat; 403 if (!(crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES)) 404 && !(mount_crypt_stat && (mount_crypt_stat->flags 405 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) 406 goto lookup_and_interpose; 407 dput(lower_dentry); 408 rc = ecryptfs_encrypt_and_encode_filename( 409 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size, 410 crypt_stat, mount_crypt_stat, ecryptfs_dentry->d_name.name, 411 ecryptfs_dentry->d_name.len); 412 if (rc) { 413 printk(KERN_ERR "%s: Error attempting to encrypt and encode " 414 "filename; rc = [%d]\n", __func__, rc); 415 goto out_d_drop; 416 } 417 lower_dentry = lookup_one_len(encrypted_and_encoded_name, 418 lower_dir_dentry, 419 encrypted_and_encoded_name_size - 1); 420 if (IS_ERR(lower_dentry)) { 421 rc = PTR_ERR(lower_dentry); 422 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on " 423 "lower_dentry = [%s]\n", __func__, rc, 424 encrypted_and_encoded_name); 425 goto out_d_drop; 426 } 427 lookup_and_interpose: 428 rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry, 429 crypt_stat, ecryptfs_dir_inode, 430 ecryptfs_nd); 431 goto out; 432 out_d_drop: 433 d_drop(ecryptfs_dentry); 434 out: 435 kfree(encrypted_and_encoded_name); 436 return ERR_PTR(rc); 437 } 438 439 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir, 440 struct dentry *new_dentry) 441 { 442 struct dentry *lower_old_dentry; 443 struct dentry *lower_new_dentry; 444 struct dentry *lower_dir_dentry; 445 u64 file_size_save; 446 int rc; 447 448 file_size_save = i_size_read(old_dentry->d_inode); 449 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 450 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 451 dget(lower_old_dentry); 452 dget(lower_new_dentry); 453 lower_dir_dentry = lock_parent(lower_new_dentry); 454 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode, 455 lower_new_dentry); 456 if (rc || !lower_new_dentry->d_inode) 457 goto out_lock; 458 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0); 459 if (rc) 460 goto out_lock; 461 fsstack_copy_attr_times(dir, lower_new_dentry->d_inode); 462 fsstack_copy_inode_size(dir, lower_new_dentry->d_inode); 463 old_dentry->d_inode->i_nlink = 464 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink; 465 i_size_write(new_dentry->d_inode, file_size_save); 466 out_lock: 467 unlock_dir(lower_dir_dentry); 468 dput(lower_new_dentry); 469 dput(lower_old_dentry); 470 d_drop(lower_old_dentry); 471 d_drop(new_dentry); 472 d_drop(old_dentry); 473 return rc; 474 } 475 476 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) 477 { 478 int rc = 0; 479 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 480 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); 481 struct dentry *lower_dir_dentry; 482 483 lower_dir_dentry = lock_parent(lower_dentry); 484 rc = vfs_unlink(lower_dir_inode, lower_dentry); 485 if (rc) { 486 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); 487 goto out_unlock; 488 } 489 fsstack_copy_attr_times(dir, lower_dir_inode); 490 dentry->d_inode->i_nlink = 491 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink; 492 dentry->d_inode->i_ctime = dir->i_ctime; 493 d_drop(dentry); 494 out_unlock: 495 unlock_dir(lower_dir_dentry); 496 return rc; 497 } 498 499 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry, 500 const char *symname) 501 { 502 int rc; 503 struct dentry *lower_dentry; 504 struct dentry *lower_dir_dentry; 505 char *encoded_symname; 506 size_t encoded_symlen; 507 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 508 509 lower_dentry = ecryptfs_dentry_to_lower(dentry); 510 dget(lower_dentry); 511 lower_dir_dentry = lock_parent(lower_dentry); 512 mount_crypt_stat = &ecryptfs_superblock_to_private( 513 dir->i_sb)->mount_crypt_stat; 514 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname, 515 &encoded_symlen, 516 NULL, 517 mount_crypt_stat, symname, 518 strlen(symname)); 519 if (rc) 520 goto out_lock; 521 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry, 522 encoded_symname); 523 kfree(encoded_symname); 524 if (rc || !lower_dentry->d_inode) 525 goto out_lock; 526 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 527 if (rc) 528 goto out_lock; 529 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 530 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 531 out_lock: 532 unlock_dir(lower_dir_dentry); 533 dput(lower_dentry); 534 if (!dentry->d_inode) 535 d_drop(dentry); 536 return rc; 537 } 538 539 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 540 { 541 int rc; 542 struct dentry *lower_dentry; 543 struct dentry *lower_dir_dentry; 544 545 lower_dentry = ecryptfs_dentry_to_lower(dentry); 546 lower_dir_dentry = lock_parent(lower_dentry); 547 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode); 548 if (rc || !lower_dentry->d_inode) 549 goto out; 550 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 551 if (rc) 552 goto out; 553 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 554 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 555 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 556 out: 557 unlock_dir(lower_dir_dentry); 558 if (!dentry->d_inode) 559 d_drop(dentry); 560 return rc; 561 } 562 563 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) 564 { 565 struct dentry *lower_dentry; 566 struct dentry *lower_dir_dentry; 567 int rc; 568 569 lower_dentry = ecryptfs_dentry_to_lower(dentry); 570 dget(dentry); 571 lower_dir_dentry = lock_parent(lower_dentry); 572 dget(lower_dentry); 573 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry); 574 dput(lower_dentry); 575 if (!rc) 576 d_delete(lower_dentry); 577 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 578 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 579 unlock_dir(lower_dir_dentry); 580 if (!rc) 581 d_drop(dentry); 582 dput(dentry); 583 return rc; 584 } 585 586 static int 587 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 588 { 589 int rc; 590 struct dentry *lower_dentry; 591 struct dentry *lower_dir_dentry; 592 593 lower_dentry = ecryptfs_dentry_to_lower(dentry); 594 lower_dir_dentry = lock_parent(lower_dentry); 595 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); 596 if (rc || !lower_dentry->d_inode) 597 goto out; 598 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 599 if (rc) 600 goto out; 601 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 602 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 603 out: 604 unlock_dir(lower_dir_dentry); 605 if (!dentry->d_inode) 606 d_drop(dentry); 607 return rc; 608 } 609 610 static int 611 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, 612 struct inode *new_dir, struct dentry *new_dentry) 613 { 614 int rc; 615 struct dentry *lower_old_dentry; 616 struct dentry *lower_new_dentry; 617 struct dentry *lower_old_dir_dentry; 618 struct dentry *lower_new_dir_dentry; 619 620 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 621 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 622 dget(lower_old_dentry); 623 dget(lower_new_dentry); 624 lower_old_dir_dentry = dget_parent(lower_old_dentry); 625 lower_new_dir_dentry = dget_parent(lower_new_dentry); 626 lock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 627 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry, 628 lower_new_dir_dentry->d_inode, lower_new_dentry); 629 if (rc) 630 goto out_lock; 631 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL); 632 if (new_dir != old_dir) 633 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL); 634 out_lock: 635 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 636 dput(lower_new_dentry->d_parent); 637 dput(lower_old_dentry->d_parent); 638 dput(lower_new_dentry); 639 dput(lower_old_dentry); 640 return rc; 641 } 642 643 static int 644 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz) 645 { 646 char *lower_buf; 647 struct dentry *lower_dentry; 648 struct ecryptfs_crypt_stat *crypt_stat; 649 char *plaintext_name; 650 size_t plaintext_name_size; 651 mm_segment_t old_fs; 652 int rc; 653 654 lower_dentry = ecryptfs_dentry_to_lower(dentry); 655 if (!lower_dentry->d_inode->i_op->readlink) { 656 rc = -EINVAL; 657 goto out; 658 } 659 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 660 /* Released in this function */ 661 lower_buf = kmalloc(bufsiz, GFP_KERNEL); 662 if (lower_buf == NULL) { 663 printk(KERN_ERR "%s: Out of memory whilst attempting to " 664 "kmalloc [%d] bytes\n", __func__, bufsiz); 665 rc = -ENOMEM; 666 goto out; 667 } 668 old_fs = get_fs(); 669 set_fs(get_ds()); 670 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry, 671 (char __user *)lower_buf, 672 bufsiz); 673 set_fs(old_fs); 674 if (rc >= 0) { 675 rc = ecryptfs_decode_and_decrypt_filename(&plaintext_name, 676 &plaintext_name_size, 677 dentry, lower_buf, 678 rc); 679 if (rc) { 680 printk(KERN_ERR "%s: Error attempting to decode and " 681 "decrypt filename; rc = [%d]\n", __func__, 682 rc); 683 goto out_free_lower_buf; 684 } 685 rc = copy_to_user(buf, plaintext_name, plaintext_name_size); 686 if (rc) 687 rc = -EFAULT; 688 else 689 rc = plaintext_name_size; 690 kfree(plaintext_name); 691 fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode); 692 } 693 out_free_lower_buf: 694 kfree(lower_buf); 695 out: 696 return rc; 697 } 698 699 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd) 700 { 701 char *buf; 702 int len = PAGE_SIZE, rc; 703 mm_segment_t old_fs; 704 705 /* Released in ecryptfs_put_link(); only release here on error */ 706 buf = kmalloc(len, GFP_KERNEL); 707 if (!buf) { 708 rc = -ENOMEM; 709 goto out; 710 } 711 old_fs = get_fs(); 712 set_fs(get_ds()); 713 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len); 714 set_fs(old_fs); 715 if (rc < 0) 716 goto out_free; 717 else 718 buf[rc] = '\0'; 719 rc = 0; 720 nd_set_link(nd, buf); 721 goto out; 722 out_free: 723 kfree(buf); 724 out: 725 return ERR_PTR(rc); 726 } 727 728 static void 729 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr) 730 { 731 /* Free the char* */ 732 kfree(nd_get_link(nd)); 733 } 734 735 /** 736 * upper_size_to_lower_size 737 * @crypt_stat: Crypt_stat associated with file 738 * @upper_size: Size of the upper file 739 * 740 * Calculate the required size of the lower file based on the 741 * specified size of the upper file. This calculation is based on the 742 * number of headers in the underlying file and the extent size. 743 * 744 * Returns Calculated size of the lower file. 745 */ 746 static loff_t 747 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, 748 loff_t upper_size) 749 { 750 loff_t lower_size; 751 752 lower_size = crypt_stat->num_header_bytes_at_front; 753 if (upper_size != 0) { 754 loff_t num_extents; 755 756 num_extents = upper_size >> crypt_stat->extent_shift; 757 if (upper_size & ~crypt_stat->extent_mask) 758 num_extents++; 759 lower_size += (num_extents * crypt_stat->extent_size); 760 } 761 return lower_size; 762 } 763 764 /** 765 * ecryptfs_truncate 766 * @dentry: The ecryptfs layer dentry 767 * @new_length: The length to expand the file to 768 * 769 * Function to handle truncations modifying the size of the file. Note 770 * that the file sizes are interpolated. When expanding, we are simply 771 * writing strings of 0's out. When truncating, we need to modify the 772 * underlying file size according to the page index interpolations. 773 * 774 * Returns zero on success; non-zero otherwise 775 */ 776 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) 777 { 778 int rc = 0; 779 struct inode *inode = dentry->d_inode; 780 struct dentry *lower_dentry; 781 struct file fake_ecryptfs_file; 782 struct ecryptfs_crypt_stat *crypt_stat; 783 loff_t i_size = i_size_read(inode); 784 loff_t lower_size_before_truncate; 785 loff_t lower_size_after_truncate; 786 787 if (unlikely((new_length == i_size))) 788 goto out; 789 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 790 /* Set up a fake ecryptfs file, this is used to interface with 791 * the file in the underlying filesystem so that the 792 * truncation has an effect there as well. */ 793 memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file)); 794 fake_ecryptfs_file.f_path.dentry = dentry; 795 /* Released at out_free: label */ 796 ecryptfs_set_file_private(&fake_ecryptfs_file, 797 kmem_cache_alloc(ecryptfs_file_info_cache, 798 GFP_KERNEL)); 799 if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) { 800 rc = -ENOMEM; 801 goto out; 802 } 803 lower_dentry = ecryptfs_dentry_to_lower(dentry); 804 ecryptfs_set_file_lower( 805 &fake_ecryptfs_file, 806 ecryptfs_inode_to_private(dentry->d_inode)->lower_file); 807 /* Switch on growing or shrinking file */ 808 if (new_length > i_size) { 809 char zero[] = { 0x00 }; 810 811 /* Write a single 0 at the last position of the file; 812 * this triggers code that will fill in 0's throughout 813 * the intermediate portion of the previous end of the 814 * file and the new and of the file */ 815 rc = ecryptfs_write(&fake_ecryptfs_file, zero, 816 (new_length - 1), 1); 817 } else { /* new_length < i_size_read(inode) */ 818 /* We're chopping off all the pages down do the page 819 * in which new_length is located. Fill in the end of 820 * that page from (new_length & ~PAGE_CACHE_MASK) to 821 * PAGE_CACHE_SIZE with zeros. */ 822 size_t num_zeros = (PAGE_CACHE_SIZE 823 - (new_length & ~PAGE_CACHE_MASK)); 824 825 if (num_zeros) { 826 char *zeros_virt; 827 828 zeros_virt = kzalloc(num_zeros, GFP_KERNEL); 829 if (!zeros_virt) { 830 rc = -ENOMEM; 831 goto out_free; 832 } 833 rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt, 834 new_length, num_zeros); 835 kfree(zeros_virt); 836 if (rc) { 837 printk(KERN_ERR "Error attempting to zero out " 838 "the remainder of the end page on " 839 "reducing truncate; rc = [%d]\n", rc); 840 goto out_free; 841 } 842 } 843 vmtruncate(inode, new_length); 844 rc = ecryptfs_write_inode_size_to_metadata(inode); 845 if (rc) { 846 printk(KERN_ERR "Problem with " 847 "ecryptfs_write_inode_size_to_metadata; " 848 "rc = [%d]\n", rc); 849 goto out_free; 850 } 851 /* We are reducing the size of the ecryptfs file, and need to 852 * know if we need to reduce the size of the lower file. */ 853 lower_size_before_truncate = 854 upper_size_to_lower_size(crypt_stat, i_size); 855 lower_size_after_truncate = 856 upper_size_to_lower_size(crypt_stat, new_length); 857 if (lower_size_after_truncate < lower_size_before_truncate) 858 vmtruncate(lower_dentry->d_inode, 859 lower_size_after_truncate); 860 } 861 out_free: 862 if (ecryptfs_file_to_private(&fake_ecryptfs_file)) 863 kmem_cache_free(ecryptfs_file_info_cache, 864 ecryptfs_file_to_private(&fake_ecryptfs_file)); 865 out: 866 return rc; 867 } 868 869 static int 870 ecryptfs_permission(struct inode *inode, int mask) 871 { 872 return inode_permission(ecryptfs_inode_to_lower(inode), mask); 873 } 874 875 /** 876 * ecryptfs_setattr 877 * @dentry: dentry handle to the inode to modify 878 * @ia: Structure with flags of what to change and values 879 * 880 * Updates the metadata of an inode. If the update is to the size 881 * i.e. truncation, then ecryptfs_truncate will handle the size modification 882 * of both the ecryptfs inode and the lower inode. 883 * 884 * All other metadata changes will be passed right to the lower filesystem, 885 * and we will just update our inode to look like the lower. 886 */ 887 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) 888 { 889 int rc = 0; 890 struct dentry *lower_dentry; 891 struct inode *inode; 892 struct inode *lower_inode; 893 struct ecryptfs_crypt_stat *crypt_stat; 894 895 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 896 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) 897 ecryptfs_init_crypt_stat(crypt_stat); 898 inode = dentry->d_inode; 899 lower_inode = ecryptfs_inode_to_lower(inode); 900 lower_dentry = ecryptfs_dentry_to_lower(dentry); 901 mutex_lock(&crypt_stat->cs_mutex); 902 if (S_ISDIR(dentry->d_inode->i_mode)) 903 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 904 else if (S_ISREG(dentry->d_inode->i_mode) 905 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) 906 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) { 907 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 908 909 mount_crypt_stat = &ecryptfs_superblock_to_private( 910 dentry->d_sb)->mount_crypt_stat; 911 rc = ecryptfs_read_metadata(dentry); 912 if (rc) { 913 if (!(mount_crypt_stat->flags 914 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { 915 rc = -EIO; 916 printk(KERN_WARNING "Either the lower file " 917 "is not in a valid eCryptfs format, " 918 "or the key could not be retrieved. " 919 "Plaintext passthrough mode is not " 920 "enabled; returning -EIO\n"); 921 mutex_unlock(&crypt_stat->cs_mutex); 922 goto out; 923 } 924 rc = 0; 925 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 926 mutex_unlock(&crypt_stat->cs_mutex); 927 goto out; 928 } 929 } 930 mutex_unlock(&crypt_stat->cs_mutex); 931 if (ia->ia_valid & ATTR_SIZE) { 932 ecryptfs_printk(KERN_DEBUG, 933 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n", 934 ia->ia_valid, ATTR_SIZE); 935 rc = ecryptfs_truncate(dentry, ia->ia_size); 936 /* ecryptfs_truncate handles resizing of the lower file */ 937 ia->ia_valid &= ~ATTR_SIZE; 938 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n", 939 ia->ia_valid); 940 if (rc < 0) 941 goto out; 942 } 943 944 /* 945 * mode change is for clearing setuid/setgid bits. Allow lower fs 946 * to interpret this in its own way. 947 */ 948 if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) 949 ia->ia_valid &= ~ATTR_MODE; 950 951 mutex_lock(&lower_dentry->d_inode->i_mutex); 952 rc = notify_change(lower_dentry, ia); 953 mutex_unlock(&lower_dentry->d_inode->i_mutex); 954 out: 955 fsstack_copy_attr_all(inode, lower_inode, NULL); 956 return rc; 957 } 958 959 int 960 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value, 961 size_t size, int flags) 962 { 963 int rc = 0; 964 struct dentry *lower_dentry; 965 966 lower_dentry = ecryptfs_dentry_to_lower(dentry); 967 if (!lower_dentry->d_inode->i_op->setxattr) { 968 rc = -ENOSYS; 969 goto out; 970 } 971 mutex_lock(&lower_dentry->d_inode->i_mutex); 972 rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value, 973 size, flags); 974 mutex_unlock(&lower_dentry->d_inode->i_mutex); 975 out: 976 return rc; 977 } 978 979 ssize_t 980 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name, 981 void *value, size_t size) 982 { 983 int rc = 0; 984 985 if (!lower_dentry->d_inode->i_op->getxattr) { 986 rc = -ENOSYS; 987 goto out; 988 } 989 mutex_lock(&lower_dentry->d_inode->i_mutex); 990 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value, 991 size); 992 mutex_unlock(&lower_dentry->d_inode->i_mutex); 993 out: 994 return rc; 995 } 996 997 static ssize_t 998 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value, 999 size_t size) 1000 { 1001 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name, 1002 value, size); 1003 } 1004 1005 static ssize_t 1006 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size) 1007 { 1008 int rc = 0; 1009 struct dentry *lower_dentry; 1010 1011 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1012 if (!lower_dentry->d_inode->i_op->listxattr) { 1013 rc = -ENOSYS; 1014 goto out; 1015 } 1016 mutex_lock(&lower_dentry->d_inode->i_mutex); 1017 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size); 1018 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1019 out: 1020 return rc; 1021 } 1022 1023 static int ecryptfs_removexattr(struct dentry *dentry, const char *name) 1024 { 1025 int rc = 0; 1026 struct dentry *lower_dentry; 1027 1028 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1029 if (!lower_dentry->d_inode->i_op->removexattr) { 1030 rc = -ENOSYS; 1031 goto out; 1032 } 1033 mutex_lock(&lower_dentry->d_inode->i_mutex); 1034 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name); 1035 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1036 out: 1037 return rc; 1038 } 1039 1040 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode) 1041 { 1042 if ((ecryptfs_inode_to_lower(inode) 1043 == (struct inode *)candidate_lower_inode)) 1044 return 1; 1045 else 1046 return 0; 1047 } 1048 1049 int ecryptfs_inode_set(struct inode *inode, void *lower_inode) 1050 { 1051 ecryptfs_init_inode(inode, (struct inode *)lower_inode); 1052 return 0; 1053 } 1054 1055 const struct inode_operations ecryptfs_symlink_iops = { 1056 .readlink = ecryptfs_readlink, 1057 .follow_link = ecryptfs_follow_link, 1058 .put_link = ecryptfs_put_link, 1059 .permission = ecryptfs_permission, 1060 .setattr = ecryptfs_setattr, 1061 .setxattr = ecryptfs_setxattr, 1062 .getxattr = ecryptfs_getxattr, 1063 .listxattr = ecryptfs_listxattr, 1064 .removexattr = ecryptfs_removexattr 1065 }; 1066 1067 const struct inode_operations ecryptfs_dir_iops = { 1068 .create = ecryptfs_create, 1069 .lookup = ecryptfs_lookup, 1070 .link = ecryptfs_link, 1071 .unlink = ecryptfs_unlink, 1072 .symlink = ecryptfs_symlink, 1073 .mkdir = ecryptfs_mkdir, 1074 .rmdir = ecryptfs_rmdir, 1075 .mknod = ecryptfs_mknod, 1076 .rename = ecryptfs_rename, 1077 .permission = ecryptfs_permission, 1078 .setattr = ecryptfs_setattr, 1079 .setxattr = ecryptfs_setxattr, 1080 .getxattr = ecryptfs_getxattr, 1081 .listxattr = ecryptfs_listxattr, 1082 .removexattr = ecryptfs_removexattr 1083 }; 1084 1085 const struct inode_operations ecryptfs_main_iops = { 1086 .permission = ecryptfs_permission, 1087 .setattr = ecryptfs_setattr, 1088 .setxattr = ecryptfs_setxattr, 1089 .getxattr = ecryptfs_getxattr, 1090 .listxattr = ecryptfs_listxattr, 1091 .removexattr = ecryptfs_removexattr 1092 }; 1093