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 inode *ecryptfs_dir_inode, 250 struct nameidata *ecryptfs_nd) 251 { 252 struct dentry *lower_dir_dentry; 253 struct vfsmount *lower_mnt; 254 struct inode *lower_inode; 255 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 256 struct ecryptfs_crypt_stat *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 crypt_stat = &ecryptfs_inode_to_private( 318 ecryptfs_dentry->d_inode)->crypt_stat; 319 /* TODO: lock for crypt_stat comparison */ 320 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) 321 ecryptfs_set_default_sizes(crypt_stat); 322 rc = ecryptfs_read_and_validate_header_region(page_virt, 323 ecryptfs_dentry->d_inode); 324 if (rc) { 325 rc = ecryptfs_read_and_validate_xattr_region(page_virt, 326 ecryptfs_dentry); 327 if (rc) { 328 rc = 0; 329 goto out_free_kmem; 330 } 331 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; 332 } 333 mount_crypt_stat = &ecryptfs_superblock_to_private( 334 ecryptfs_dentry->d_sb)->mount_crypt_stat; 335 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { 336 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) 337 file_size = (crypt_stat->num_header_bytes_at_front 338 + i_size_read(lower_dentry->d_inode)); 339 else 340 file_size = i_size_read(lower_dentry->d_inode); 341 } else { 342 file_size = get_unaligned_be64(page_virt); 343 } 344 i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size); 345 out_free_kmem: 346 kmem_cache_free(ecryptfs_header_cache_2, page_virt); 347 goto out; 348 out_dput: 349 dput(lower_dentry); 350 d_drop(ecryptfs_dentry); 351 out: 352 return rc; 353 } 354 355 /** 356 * ecryptfs_lookup 357 * @ecryptfs_dir_inode: The eCryptfs directory inode 358 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up 359 * @ecryptfs_nd: nameidata; may be NULL 360 * 361 * Find a file on disk. If the file does not exist, then we'll add it to the 362 * dentry cache and continue on to read it from the disk. 363 */ 364 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode, 365 struct dentry *ecryptfs_dentry, 366 struct nameidata *ecryptfs_nd) 367 { 368 char *encrypted_and_encoded_name = NULL; 369 size_t encrypted_and_encoded_name_size; 370 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 371 struct dentry *lower_dir_dentry, *lower_dentry; 372 int rc = 0; 373 374 ecryptfs_dentry->d_op = &ecryptfs_dops; 375 if ((ecryptfs_dentry->d_name.len == 1 376 && !strcmp(ecryptfs_dentry->d_name.name, ".")) 377 || (ecryptfs_dentry->d_name.len == 2 378 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) { 379 goto out_d_drop; 380 } 381 lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent); 382 mutex_lock(&lower_dir_dentry->d_inode->i_mutex); 383 lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name, 384 lower_dir_dentry, 385 ecryptfs_dentry->d_name.len); 386 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex); 387 if (IS_ERR(lower_dentry)) { 388 rc = PTR_ERR(lower_dentry); 389 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on " 390 "lower_dentry = [%s]\n", __func__, rc, 391 ecryptfs_dentry->d_name.name); 392 goto out_d_drop; 393 } 394 if (lower_dentry->d_inode) 395 goto lookup_and_interpose; 396 mount_crypt_stat = &ecryptfs_superblock_to_private( 397 ecryptfs_dentry->d_sb)->mount_crypt_stat; 398 if (!(mount_crypt_stat 399 && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) 400 goto lookup_and_interpose; 401 dput(lower_dentry); 402 rc = ecryptfs_encrypt_and_encode_filename( 403 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size, 404 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name, 405 ecryptfs_dentry->d_name.len); 406 if (rc) { 407 printk(KERN_ERR "%s: Error attempting to encrypt and encode " 408 "filename; rc = [%d]\n", __func__, rc); 409 goto out_d_drop; 410 } 411 mutex_lock(&lower_dir_dentry->d_inode->i_mutex); 412 lower_dentry = lookup_one_len(encrypted_and_encoded_name, 413 lower_dir_dentry, 414 encrypted_and_encoded_name_size - 1); 415 mutex_unlock(&lower_dir_dentry->d_inode->i_mutex); 416 if (IS_ERR(lower_dentry)) { 417 rc = PTR_ERR(lower_dentry); 418 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on " 419 "lower_dentry = [%s]\n", __func__, rc, 420 encrypted_and_encoded_name); 421 goto out_d_drop; 422 } 423 lookup_and_interpose: 424 rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry, 425 ecryptfs_dir_inode, 426 ecryptfs_nd); 427 goto out; 428 out_d_drop: 429 d_drop(ecryptfs_dentry); 430 out: 431 kfree(encrypted_and_encoded_name); 432 return ERR_PTR(rc); 433 } 434 435 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir, 436 struct dentry *new_dentry) 437 { 438 struct dentry *lower_old_dentry; 439 struct dentry *lower_new_dentry; 440 struct dentry *lower_dir_dentry; 441 u64 file_size_save; 442 int rc; 443 444 file_size_save = i_size_read(old_dentry->d_inode); 445 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 446 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 447 dget(lower_old_dentry); 448 dget(lower_new_dentry); 449 lower_dir_dentry = lock_parent(lower_new_dentry); 450 rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode, 451 lower_new_dentry); 452 if (rc || !lower_new_dentry->d_inode) 453 goto out_lock; 454 rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0); 455 if (rc) 456 goto out_lock; 457 fsstack_copy_attr_times(dir, lower_new_dentry->d_inode); 458 fsstack_copy_inode_size(dir, lower_new_dentry->d_inode); 459 old_dentry->d_inode->i_nlink = 460 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink; 461 i_size_write(new_dentry->d_inode, file_size_save); 462 out_lock: 463 unlock_dir(lower_dir_dentry); 464 dput(lower_new_dentry); 465 dput(lower_old_dentry); 466 d_drop(lower_old_dentry); 467 d_drop(new_dentry); 468 d_drop(old_dentry); 469 return rc; 470 } 471 472 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) 473 { 474 int rc = 0; 475 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 476 struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); 477 struct dentry *lower_dir_dentry; 478 479 lower_dir_dentry = lock_parent(lower_dentry); 480 rc = vfs_unlink(lower_dir_inode, lower_dentry); 481 if (rc) { 482 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); 483 goto out_unlock; 484 } 485 fsstack_copy_attr_times(dir, lower_dir_inode); 486 dentry->d_inode->i_nlink = 487 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink; 488 dentry->d_inode->i_ctime = dir->i_ctime; 489 d_drop(dentry); 490 out_unlock: 491 unlock_dir(lower_dir_dentry); 492 return rc; 493 } 494 495 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry, 496 const char *symname) 497 { 498 int rc; 499 struct dentry *lower_dentry; 500 struct dentry *lower_dir_dentry; 501 char *encoded_symname; 502 size_t encoded_symlen; 503 struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL; 504 505 lower_dentry = ecryptfs_dentry_to_lower(dentry); 506 dget(lower_dentry); 507 lower_dir_dentry = lock_parent(lower_dentry); 508 mount_crypt_stat = &ecryptfs_superblock_to_private( 509 dir->i_sb)->mount_crypt_stat; 510 rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname, 511 &encoded_symlen, 512 NULL, 513 mount_crypt_stat, symname, 514 strlen(symname)); 515 if (rc) 516 goto out_lock; 517 rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry, 518 encoded_symname); 519 kfree(encoded_symname); 520 if (rc || !lower_dentry->d_inode) 521 goto out_lock; 522 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 523 if (rc) 524 goto out_lock; 525 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 526 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 527 out_lock: 528 unlock_dir(lower_dir_dentry); 529 dput(lower_dentry); 530 if (!dentry->d_inode) 531 d_drop(dentry); 532 return rc; 533 } 534 535 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 536 { 537 int rc; 538 struct dentry *lower_dentry; 539 struct dentry *lower_dir_dentry; 540 541 lower_dentry = ecryptfs_dentry_to_lower(dentry); 542 lower_dir_dentry = lock_parent(lower_dentry); 543 rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode); 544 if (rc || !lower_dentry->d_inode) 545 goto out; 546 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 547 if (rc) 548 goto out; 549 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 550 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 551 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 552 out: 553 unlock_dir(lower_dir_dentry); 554 if (!dentry->d_inode) 555 d_drop(dentry); 556 return rc; 557 } 558 559 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) 560 { 561 struct dentry *lower_dentry; 562 struct dentry *lower_dir_dentry; 563 int rc; 564 565 lower_dentry = ecryptfs_dentry_to_lower(dentry); 566 dget(dentry); 567 lower_dir_dentry = lock_parent(lower_dentry); 568 dget(lower_dentry); 569 rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry); 570 dput(lower_dentry); 571 if (!rc) 572 d_delete(lower_dentry); 573 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 574 dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; 575 unlock_dir(lower_dir_dentry); 576 if (!rc) 577 d_drop(dentry); 578 dput(dentry); 579 return rc; 580 } 581 582 static int 583 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 584 { 585 int rc; 586 struct dentry *lower_dentry; 587 struct dentry *lower_dir_dentry; 588 589 lower_dentry = ecryptfs_dentry_to_lower(dentry); 590 lower_dir_dentry = lock_parent(lower_dentry); 591 rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); 592 if (rc || !lower_dentry->d_inode) 593 goto out; 594 rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); 595 if (rc) 596 goto out; 597 fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); 598 fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); 599 out: 600 unlock_dir(lower_dir_dentry); 601 if (!dentry->d_inode) 602 d_drop(dentry); 603 return rc; 604 } 605 606 static int 607 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, 608 struct inode *new_dir, struct dentry *new_dentry) 609 { 610 int rc; 611 struct dentry *lower_old_dentry; 612 struct dentry *lower_new_dentry; 613 struct dentry *lower_old_dir_dentry; 614 struct dentry *lower_new_dir_dentry; 615 616 lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); 617 lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); 618 dget(lower_old_dentry); 619 dget(lower_new_dentry); 620 lower_old_dir_dentry = dget_parent(lower_old_dentry); 621 lower_new_dir_dentry = dget_parent(lower_new_dentry); 622 lock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 623 rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry, 624 lower_new_dir_dentry->d_inode, lower_new_dentry); 625 if (rc) 626 goto out_lock; 627 fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL); 628 if (new_dir != old_dir) 629 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL); 630 out_lock: 631 unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry); 632 dput(lower_new_dentry->d_parent); 633 dput(lower_old_dentry->d_parent); 634 dput(lower_new_dentry); 635 dput(lower_old_dentry); 636 return rc; 637 } 638 639 static int 640 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz) 641 { 642 char *lower_buf; 643 size_t lower_bufsiz; 644 struct dentry *lower_dentry; 645 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 646 char *plaintext_name; 647 size_t plaintext_name_size; 648 mm_segment_t old_fs; 649 int rc; 650 651 lower_dentry = ecryptfs_dentry_to_lower(dentry); 652 if (!lower_dentry->d_inode->i_op->readlink) { 653 rc = -EINVAL; 654 goto out; 655 } 656 mount_crypt_stat = &ecryptfs_superblock_to_private( 657 dentry->d_sb)->mount_crypt_stat; 658 /* 659 * If the lower filename is encrypted, it will result in a significantly 660 * longer name. If needed, truncate the name after decode and decrypt. 661 */ 662 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) 663 lower_bufsiz = PATH_MAX; 664 else 665 lower_bufsiz = bufsiz; 666 /* Released in this function */ 667 lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL); 668 if (lower_buf == NULL) { 669 printk(KERN_ERR "%s: Out of memory whilst attempting to " 670 "kmalloc [%zd] bytes\n", __func__, lower_bufsiz); 671 rc = -ENOMEM; 672 goto out; 673 } 674 old_fs = get_fs(); 675 set_fs(get_ds()); 676 rc = lower_dentry->d_inode->i_op->readlink(lower_dentry, 677 (char __user *)lower_buf, 678 lower_bufsiz); 679 set_fs(old_fs); 680 if (rc >= 0) { 681 rc = ecryptfs_decode_and_decrypt_filename(&plaintext_name, 682 &plaintext_name_size, 683 dentry, lower_buf, 684 rc); 685 if (rc) { 686 printk(KERN_ERR "%s: Error attempting to decode and " 687 "decrypt filename; rc = [%d]\n", __func__, 688 rc); 689 goto out_free_lower_buf; 690 } 691 /* Check for bufsiz <= 0 done in sys_readlinkat() */ 692 rc = copy_to_user(buf, plaintext_name, 693 min((size_t) bufsiz, plaintext_name_size)); 694 if (rc) 695 rc = -EFAULT; 696 else 697 rc = plaintext_name_size; 698 kfree(plaintext_name); 699 fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode); 700 } 701 out_free_lower_buf: 702 kfree(lower_buf); 703 out: 704 return rc; 705 } 706 707 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd) 708 { 709 char *buf; 710 int len = PAGE_SIZE, rc; 711 mm_segment_t old_fs; 712 713 /* Released in ecryptfs_put_link(); only release here on error */ 714 buf = kmalloc(len, GFP_KERNEL); 715 if (!buf) { 716 rc = -ENOMEM; 717 goto out; 718 } 719 old_fs = get_fs(); 720 set_fs(get_ds()); 721 rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len); 722 set_fs(old_fs); 723 if (rc < 0) 724 goto out_free; 725 else 726 buf[rc] = '\0'; 727 rc = 0; 728 nd_set_link(nd, buf); 729 goto out; 730 out_free: 731 kfree(buf); 732 out: 733 return ERR_PTR(rc); 734 } 735 736 static void 737 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr) 738 { 739 /* Free the char* */ 740 kfree(nd_get_link(nd)); 741 } 742 743 /** 744 * upper_size_to_lower_size 745 * @crypt_stat: Crypt_stat associated with file 746 * @upper_size: Size of the upper file 747 * 748 * Calculate the required size of the lower file based on the 749 * specified size of the upper file. This calculation is based on the 750 * number of headers in the underlying file and the extent size. 751 * 752 * Returns Calculated size of the lower file. 753 */ 754 static loff_t 755 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, 756 loff_t upper_size) 757 { 758 loff_t lower_size; 759 760 lower_size = crypt_stat->num_header_bytes_at_front; 761 if (upper_size != 0) { 762 loff_t num_extents; 763 764 num_extents = upper_size >> crypt_stat->extent_shift; 765 if (upper_size & ~crypt_stat->extent_mask) 766 num_extents++; 767 lower_size += (num_extents * crypt_stat->extent_size); 768 } 769 return lower_size; 770 } 771 772 /** 773 * ecryptfs_truncate 774 * @dentry: The ecryptfs layer dentry 775 * @new_length: The length to expand the file to 776 * 777 * Function to handle truncations modifying the size of the file. Note 778 * that the file sizes are interpolated. When expanding, we are simply 779 * writing strings of 0's out. When truncating, we need to modify the 780 * underlying file size according to the page index interpolations. 781 * 782 * Returns zero on success; non-zero otherwise 783 */ 784 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) 785 { 786 int rc = 0; 787 struct inode *inode = dentry->d_inode; 788 struct dentry *lower_dentry; 789 struct file fake_ecryptfs_file; 790 struct ecryptfs_crypt_stat *crypt_stat; 791 loff_t i_size = i_size_read(inode); 792 loff_t lower_size_before_truncate; 793 loff_t lower_size_after_truncate; 794 795 if (unlikely((new_length == i_size))) 796 goto out; 797 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 798 /* Set up a fake ecryptfs file, this is used to interface with 799 * the file in the underlying filesystem so that the 800 * truncation has an effect there as well. */ 801 memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file)); 802 fake_ecryptfs_file.f_path.dentry = dentry; 803 /* Released at out_free: label */ 804 ecryptfs_set_file_private(&fake_ecryptfs_file, 805 kmem_cache_alloc(ecryptfs_file_info_cache, 806 GFP_KERNEL)); 807 if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) { 808 rc = -ENOMEM; 809 goto out; 810 } 811 lower_dentry = ecryptfs_dentry_to_lower(dentry); 812 ecryptfs_set_file_lower( 813 &fake_ecryptfs_file, 814 ecryptfs_inode_to_private(dentry->d_inode)->lower_file); 815 /* Switch on growing or shrinking file */ 816 if (new_length > i_size) { 817 char zero[] = { 0x00 }; 818 819 /* Write a single 0 at the last position of the file; 820 * this triggers code that will fill in 0's throughout 821 * the intermediate portion of the previous end of the 822 * file and the new and of the file */ 823 rc = ecryptfs_write(&fake_ecryptfs_file, zero, 824 (new_length - 1), 1); 825 } else { /* new_length < i_size_read(inode) */ 826 /* We're chopping off all the pages down do the page 827 * in which new_length is located. Fill in the end of 828 * that page from (new_length & ~PAGE_CACHE_MASK) to 829 * PAGE_CACHE_SIZE with zeros. */ 830 size_t num_zeros = (PAGE_CACHE_SIZE 831 - (new_length & ~PAGE_CACHE_MASK)); 832 833 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { 834 rc = vmtruncate(inode, new_length); 835 if (rc) 836 goto out_free; 837 rc = vmtruncate(lower_dentry->d_inode, new_length); 838 goto out_free; 839 } 840 if (num_zeros) { 841 char *zeros_virt; 842 843 zeros_virt = kzalloc(num_zeros, GFP_KERNEL); 844 if (!zeros_virt) { 845 rc = -ENOMEM; 846 goto out_free; 847 } 848 rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt, 849 new_length, num_zeros); 850 kfree(zeros_virt); 851 if (rc) { 852 printk(KERN_ERR "Error attempting to zero out " 853 "the remainder of the end page on " 854 "reducing truncate; rc = [%d]\n", rc); 855 goto out_free; 856 } 857 } 858 vmtruncate(inode, new_length); 859 rc = ecryptfs_write_inode_size_to_metadata(inode); 860 if (rc) { 861 printk(KERN_ERR "Problem with " 862 "ecryptfs_write_inode_size_to_metadata; " 863 "rc = [%d]\n", rc); 864 goto out_free; 865 } 866 /* We are reducing the size of the ecryptfs file, and need to 867 * know if we need to reduce the size of the lower file. */ 868 lower_size_before_truncate = 869 upper_size_to_lower_size(crypt_stat, i_size); 870 lower_size_after_truncate = 871 upper_size_to_lower_size(crypt_stat, new_length); 872 if (lower_size_after_truncate < lower_size_before_truncate) 873 vmtruncate(lower_dentry->d_inode, 874 lower_size_after_truncate); 875 } 876 out_free: 877 if (ecryptfs_file_to_private(&fake_ecryptfs_file)) 878 kmem_cache_free(ecryptfs_file_info_cache, 879 ecryptfs_file_to_private(&fake_ecryptfs_file)); 880 out: 881 return rc; 882 } 883 884 static int 885 ecryptfs_permission(struct inode *inode, int mask) 886 { 887 return inode_permission(ecryptfs_inode_to_lower(inode), mask); 888 } 889 890 /** 891 * ecryptfs_setattr 892 * @dentry: dentry handle to the inode to modify 893 * @ia: Structure with flags of what to change and values 894 * 895 * Updates the metadata of an inode. If the update is to the size 896 * i.e. truncation, then ecryptfs_truncate will handle the size modification 897 * of both the ecryptfs inode and the lower inode. 898 * 899 * All other metadata changes will be passed right to the lower filesystem, 900 * and we will just update our inode to look like the lower. 901 */ 902 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) 903 { 904 int rc = 0; 905 struct dentry *lower_dentry; 906 struct inode *inode; 907 struct inode *lower_inode; 908 struct ecryptfs_crypt_stat *crypt_stat; 909 910 crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; 911 if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) 912 ecryptfs_init_crypt_stat(crypt_stat); 913 inode = dentry->d_inode; 914 lower_inode = ecryptfs_inode_to_lower(inode); 915 lower_dentry = ecryptfs_dentry_to_lower(dentry); 916 mutex_lock(&crypt_stat->cs_mutex); 917 if (S_ISDIR(dentry->d_inode->i_mode)) 918 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 919 else if (S_ISREG(dentry->d_inode->i_mode) 920 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) 921 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) { 922 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 923 924 mount_crypt_stat = &ecryptfs_superblock_to_private( 925 dentry->d_sb)->mount_crypt_stat; 926 rc = ecryptfs_read_metadata(dentry); 927 if (rc) { 928 if (!(mount_crypt_stat->flags 929 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { 930 rc = -EIO; 931 printk(KERN_WARNING "Either the lower file " 932 "is not in a valid eCryptfs format, " 933 "or the key could not be retrieved. " 934 "Plaintext passthrough mode is not " 935 "enabled; returning -EIO\n"); 936 mutex_unlock(&crypt_stat->cs_mutex); 937 goto out; 938 } 939 rc = 0; 940 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); 941 } 942 } 943 mutex_unlock(&crypt_stat->cs_mutex); 944 if (ia->ia_valid & ATTR_SIZE) { 945 ecryptfs_printk(KERN_DEBUG, 946 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n", 947 ia->ia_valid, ATTR_SIZE); 948 rc = ecryptfs_truncate(dentry, ia->ia_size); 949 /* ecryptfs_truncate handles resizing of the lower file */ 950 ia->ia_valid &= ~ATTR_SIZE; 951 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n", 952 ia->ia_valid); 953 if (rc < 0) 954 goto out; 955 } 956 957 /* 958 * mode change is for clearing setuid/setgid bits. Allow lower fs 959 * to interpret this in its own way. 960 */ 961 if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) 962 ia->ia_valid &= ~ATTR_MODE; 963 964 mutex_lock(&lower_dentry->d_inode->i_mutex); 965 rc = notify_change(lower_dentry, ia); 966 mutex_unlock(&lower_dentry->d_inode->i_mutex); 967 out: 968 fsstack_copy_attr_all(inode, lower_inode, NULL); 969 return rc; 970 } 971 972 int 973 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value, 974 size_t size, int flags) 975 { 976 int rc = 0; 977 struct dentry *lower_dentry; 978 979 lower_dentry = ecryptfs_dentry_to_lower(dentry); 980 if (!lower_dentry->d_inode->i_op->setxattr) { 981 rc = -ENOSYS; 982 goto out; 983 } 984 mutex_lock(&lower_dentry->d_inode->i_mutex); 985 rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value, 986 size, flags); 987 mutex_unlock(&lower_dentry->d_inode->i_mutex); 988 out: 989 return rc; 990 } 991 992 ssize_t 993 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name, 994 void *value, size_t size) 995 { 996 int rc = 0; 997 998 if (!lower_dentry->d_inode->i_op->getxattr) { 999 rc = -ENOSYS; 1000 goto out; 1001 } 1002 mutex_lock(&lower_dentry->d_inode->i_mutex); 1003 rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value, 1004 size); 1005 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1006 out: 1007 return rc; 1008 } 1009 1010 static ssize_t 1011 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value, 1012 size_t size) 1013 { 1014 return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name, 1015 value, size); 1016 } 1017 1018 static ssize_t 1019 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size) 1020 { 1021 int rc = 0; 1022 struct dentry *lower_dentry; 1023 1024 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1025 if (!lower_dentry->d_inode->i_op->listxattr) { 1026 rc = -ENOSYS; 1027 goto out; 1028 } 1029 mutex_lock(&lower_dentry->d_inode->i_mutex); 1030 rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size); 1031 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1032 out: 1033 return rc; 1034 } 1035 1036 static int ecryptfs_removexattr(struct dentry *dentry, const char *name) 1037 { 1038 int rc = 0; 1039 struct dentry *lower_dentry; 1040 1041 lower_dentry = ecryptfs_dentry_to_lower(dentry); 1042 if (!lower_dentry->d_inode->i_op->removexattr) { 1043 rc = -ENOSYS; 1044 goto out; 1045 } 1046 mutex_lock(&lower_dentry->d_inode->i_mutex); 1047 rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name); 1048 mutex_unlock(&lower_dentry->d_inode->i_mutex); 1049 out: 1050 return rc; 1051 } 1052 1053 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode) 1054 { 1055 if ((ecryptfs_inode_to_lower(inode) 1056 == (struct inode *)candidate_lower_inode)) 1057 return 1; 1058 else 1059 return 0; 1060 } 1061 1062 int ecryptfs_inode_set(struct inode *inode, void *lower_inode) 1063 { 1064 ecryptfs_init_inode(inode, (struct inode *)lower_inode); 1065 return 0; 1066 } 1067 1068 const struct inode_operations ecryptfs_symlink_iops = { 1069 .readlink = ecryptfs_readlink, 1070 .follow_link = ecryptfs_follow_link, 1071 .put_link = ecryptfs_put_link, 1072 .permission = ecryptfs_permission, 1073 .setattr = ecryptfs_setattr, 1074 .setxattr = ecryptfs_setxattr, 1075 .getxattr = ecryptfs_getxattr, 1076 .listxattr = ecryptfs_listxattr, 1077 .removexattr = ecryptfs_removexattr 1078 }; 1079 1080 const struct inode_operations ecryptfs_dir_iops = { 1081 .create = ecryptfs_create, 1082 .lookup = ecryptfs_lookup, 1083 .link = ecryptfs_link, 1084 .unlink = ecryptfs_unlink, 1085 .symlink = ecryptfs_symlink, 1086 .mkdir = ecryptfs_mkdir, 1087 .rmdir = ecryptfs_rmdir, 1088 .mknod = ecryptfs_mknod, 1089 .rename = ecryptfs_rename, 1090 .permission = ecryptfs_permission, 1091 .setattr = ecryptfs_setattr, 1092 .setxattr = ecryptfs_setxattr, 1093 .getxattr = ecryptfs_getxattr, 1094 .listxattr = ecryptfs_listxattr, 1095 .removexattr = ecryptfs_removexattr 1096 }; 1097 1098 const struct inode_operations ecryptfs_main_iops = { 1099 .permission = ecryptfs_permission, 1100 .setattr = ecryptfs_setattr, 1101 .setxattr = ecryptfs_setxattr, 1102 .getxattr = ecryptfs_getxattr, 1103 .listxattr = ecryptfs_listxattr, 1104 .removexattr = ecryptfs_removexattr 1105 }; 1106