fs/ecryptfs/inode.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2004 Erez Zadok
   5  * Copyright (C) 2001-2004 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #include <linux/file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/dcache.h>
  30 #include <linux/namei.h>
  31 #include <linux/mount.h>
  32 #include <linux/crypto.h>
  33 #include <linux/fs_stack.h>
  34 #include <linux/slab.h>
  35 #include <linux/xattr.h>
  36 #include <asm/unaligned.h>
  37 #include "ecryptfs_kernel.h"
  38
  39 static struct dentry *lock_parent(struct dentry *dentry)
  40 {
  41         struct dentry *dir;
  42
  43         dir = dget_parent(dentry);
  44         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
  45         return dir;
  46 }
  47
  48 static void unlock_dir(struct dentry *dir)
  49 {
  50         mutex_unlock(&dir->d_inode->i_mutex);
  51         dput(dir);
  52 }
  53
  54 /**
  55  * ecryptfs_create_underlying_file
  56  * @lower_dir_inode: inode of the parent in the lower fs of the new file
  57  * @dentry: New file's dentry
  58  * @mode: The mode of the new file
  59  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  60  *
  61  * Creates the file in the lower file system.
  62  *
  63  * Returns zero on success; non-zero on error condition
  64  */
  65 static int
  66 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
  67                                 struct dentry *dentry, int mode,
  68                                 struct nameidata *nd)
  69 {
  70         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  71         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  72         struct dentry *dentry_save;
  73         struct vfsmount *vfsmount_save;
  74         unsigned int flags_save;
  75         int rc;
  76
  77         if (nd) {
  78                 dentry_save = nd->path.dentry;
  79                 vfsmount_save = nd->path.mnt;
  80                 flags_save = nd->flags;
  81                 nd->path.dentry = lower_dentry;
  82                 nd->path.mnt = lower_mnt;
  83                 nd->flags &= ~LOOKUP_OPEN;
  84         }
  85         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
  86         if (nd) {
  87                 nd->path.dentry = dentry_save;
  88                 nd->path.mnt = vfsmount_save;
  89                 nd->flags = flags_save;
  90         }
  91         return rc;
  92 }
  93
  94 /**
  95  * ecryptfs_do_create
  96  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
  97  * @ecryptfs_dentry: New file's dentry in ecryptfs
  98  * @mode: The mode of the new file
  99  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 100  *
 101  * Creates the underlying file and the eCryptfs inode which will link to
 102  * it. It will also update the eCryptfs directory inode to mimic the
 103  * stat of the lower directory inode.
 104  *
 105  * Returns zero on success; non-zero on error condition
 106  */
 107 static int
 108 ecryptfs_do_create(struct inode *directory_inode,
 109                    struct dentry *ecryptfs_dentry, int mode,
 110                    struct nameidata *nd)
 111 {
 112         int rc;
 113         struct dentry *lower_dentry;
 114         struct dentry *lower_dir_dentry;
 115
 116         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 117         lower_dir_dentry = lock_parent(lower_dentry);
 118         if (IS_ERR(lower_dir_dentry)) {
 119                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 120                                 "dentry\n");
 121                 rc = PTR_ERR(lower_dir_dentry);
 122                 goto out;
 123         }
 124         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 125                                              ecryptfs_dentry, mode, nd);
 126         if (rc) {
 127                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 128                        "rc = [%d]\n", __func__, rc);
 129                 goto out_lock;
 130         }
 131         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 132                                 directory_inode->i_sb, 0);
 133         if (rc) {
 134                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 135                 goto out_lock;
 136         }
 137         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
 138         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
 139 out_lock:
 140         unlock_dir(lower_dir_dentry);
 141 out:
 142         return rc;
 143 }
 144
 145 /**
 146  * ecryptfs_initialize_file
 147  *
 148  * Cause the file to be changed from a basic empty file to an ecryptfs
 149  * file with a header and first data page.
 150  *
 151  * Returns zero on success
 152  */
 153 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 154 {
 155         struct ecryptfs_crypt_stat *crypt_stat =
 156                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
 157         int rc = 0;
 158
 159         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 160                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 161                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 162                 goto out;
 163         }
 164         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 165         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 166         if (rc) {
 167                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 168                                 "context; rc = [%d]\n", rc);
 169                 goto out;
 170         }
 171         rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
 172         if (rc) {
 173                 printk(KERN_ERR "%s: Error attempting to initialize "
 174                         "the persistent file for the dentry with name "
 175                         "[%s]; rc = [%d]\n", __func__,
 176                         ecryptfs_dentry->d_name.name, rc);
 177                 goto out;
 178         }
 179         rc = ecryptfs_write_metadata(ecryptfs_dentry);
 180         if (rc) {
 181                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 182                 goto out;
 183         }
 184 out:
 185         return rc;
 186 }
 187
 188 /**
 189  * ecryptfs_create
 190  * @dir: The inode of the directory in which to create the file.
 191  * @dentry: The eCryptfs dentry
 192  * @mode: The mode of the new file.
 193  * @nd: nameidata
 194  *
 195  * Creates a new file.
 196  *
 197  * Returns zero on success; non-zero on error condition
 198  */
 199 static int
 200 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 201                 int mode, struct nameidata *nd)
 202 {
 203         int rc;
 204
 205         /* ecryptfs_do_create() calls ecryptfs_interpose() */
 206         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 207         if (unlikely(rc)) {
 208                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 209                                 "lower filesystem\n");
 210                 goto out;
 211         }
 212         /* At this point, a file exists on "disk"; we need to make sure
 213          * that this on disk file is prepared to be an ecryptfs file */
 214         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 215 out:
 216         return rc;
 217 }
 218
 219 /**
 220  * ecryptfs_lookup_and_interpose_lower - Perform a lookup
 221  */
 222 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
 223                                         struct dentry *lower_dentry,
 224                                         struct inode *ecryptfs_dir_inode)
 225 {
 226         struct dentry *lower_dir_dentry;
 227         struct vfsmount *lower_mnt;
 228         struct inode *lower_inode;
 229         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 230         struct ecryptfs_crypt_stat *crypt_stat;
 231         char *page_virt = NULL;
 232         u64 file_size;
 233         int rc = 0;
 234
 235         lower_dir_dentry = lower_dentry->d_parent;
 236         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
 237                                    ecryptfs_dentry->d_parent));
 238         lower_inode = lower_dentry->d_inode;
 239         fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
 240         BUG_ON(!lower_dentry->d_count);
 241         ecryptfs_set_dentry_private(ecryptfs_dentry,
 242                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 243                                                      GFP_KERNEL));
 244         if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
 245                 rc = -ENOMEM;
 246                 printk(KERN_ERR "%s: Out of memory whilst attempting "
 247                        "to allocate ecryptfs_dentry_info struct\n",
 248                         __func__);
 249                 goto out_put;
 250         }
 251         ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
 252         ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
 253         if (!lower_dentry->d_inode) {
 254                 /* We want to add because we couldn't find in lower */
 255                 d_add(ecryptfs_dentry, NULL);
 256                 goto out;
 257         }
 258         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 259                                 ecryptfs_dir_inode->i_sb,
 260                                 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
 261         if (rc) {
 262                 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
 263                        __func__, rc);
 264                 goto out;
 265         }
 266         if (S_ISDIR(lower_inode->i_mode))
 267                 goto out;
 268         if (S_ISLNK(lower_inode->i_mode))
 269                 goto out;
 270         if (special_file(lower_inode->i_mode))
 271                 goto out;
 272         /* Released in this function */
 273         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
 274         if (!page_virt) {
 275                 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
 276                        __func__);
 277                 rc = -ENOMEM;
 278                 goto out;
 279         }
 280         rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
 281         if (rc) {
 282                 printk(KERN_ERR "%s: Error attempting to initialize "
 283                         "the persistent file for the dentry with name "
 284                         "[%s]; rc = [%d]\n", __func__,
 285                         ecryptfs_dentry->d_name.name, rc);
 286                 goto out_free_kmem;
 287         }
 288         crypt_stat = &ecryptfs_inode_to_private(
 289                                         ecryptfs_dentry->d_inode)->crypt_stat;
 290         /* TODO: lock for crypt_stat comparison */
 291         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 292                         ecryptfs_set_default_sizes(crypt_stat);
 293         rc = ecryptfs_read_and_validate_header_region(page_virt,
 294                                                       ecryptfs_dentry->d_inode);
 295         if (rc) {
 296                 memset(page_virt, 0, PAGE_CACHE_SIZE);
 297                 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
 298                                                              ecryptfs_dentry);
 299                 if (rc) {
 300                         rc = 0;
 301                         goto out_free_kmem;
 302                 }
 303                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 304         }
 305         mount_crypt_stat = &ecryptfs_superblock_to_private(
 306                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 307         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 308                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 309                         file_size = (crypt_stat->metadata_size
 310                                      + i_size_read(lower_dentry->d_inode));
 311                 else
 312                         file_size = i_size_read(lower_dentry->d_inode);
 313         } else {
 314                 file_size = get_unaligned_be64(page_virt);
 315         }
 316         i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
 317 out_free_kmem:
 318         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 319         goto out;
 320 out_put:
 321         dput(lower_dentry);
 322         mntput(lower_mnt);
 323         d_drop(ecryptfs_dentry);
 324 out:
 325         return rc;
 326 }
 327
 328 /**
 329  * ecryptfs_lookup
 330  * @ecryptfs_dir_inode: The eCryptfs directory inode
 331  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 332  * @ecryptfs_nd: nameidata; may be NULL
 333  *
 334  * Find a file on disk. If the file does not exist, then we'll add it to the
 335  * dentry cache and continue on to read it from the disk.
 336  */
 337 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 338                                       struct dentry *ecryptfs_dentry,
 339                                       struct nameidata *ecryptfs_nd)
 340 {
 341         char *encrypted_and_encoded_name = NULL;
 342         size_t encrypted_and_encoded_name_size;
 343         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 344         struct dentry *lower_dir_dentry, *lower_dentry;
 345         int rc = 0;
 346
 347         if ((ecryptfs_dentry->d_name.len == 1
 348              && !strcmp(ecryptfs_dentry->d_name.name, "."))
 349             || (ecryptfs_dentry->d_name.len == 2
 350                 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
 351                 goto out_d_drop;
 352         }
 353         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 354         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
 355         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
 356                                       lower_dir_dentry,
 357                                       ecryptfs_dentry->d_name.len);
 358         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
 359         if (IS_ERR(lower_dentry)) {
 360                 rc = PTR_ERR(lower_dentry);
 361                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 362                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
 363                                 encrypted_and_encoded_name);
 364                 goto out_d_drop;
 365         }
 366         if (lower_dentry->d_inode)
 367                 goto lookup_and_interpose;
 368         mount_crypt_stat = &ecryptfs_superblock_to_private(
 369                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 370         if (!(mount_crypt_stat
 371             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
 372                 goto lookup_and_interpose;
 373         dput(lower_dentry);
 374         rc = ecryptfs_encrypt_and_encode_filename(
 375                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
 376                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
 377                 ecryptfs_dentry->d_name.len);
 378         if (rc) {
 379                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 380                        "filename; rc = [%d]\n", __func__, rc);
 381                 goto out_d_drop;
 382         }
 383         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
 384         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
 385                                       lower_dir_dentry,
 386                                       encrypted_and_encoded_name_size);
 387         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
 388         if (IS_ERR(lower_dentry)) {
 389                 rc = PTR_ERR(lower_dentry);
 390                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 391                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
 392                                 encrypted_and_encoded_name);
 393                 goto out_d_drop;
 394         }
 395 lookup_and_interpose:
 396         rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
 397                                                  ecryptfs_dir_inode);
 398         goto out;
 399 out_d_drop:
 400         d_drop(ecryptfs_dentry);
 401 out:
 402         kfree(encrypted_and_encoded_name);
 403         return ERR_PTR(rc);
 404 }
 405
 406 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 407                          struct dentry *new_dentry)
 408 {
 409         struct dentry *lower_old_dentry;
 410         struct dentry *lower_new_dentry;
 411         struct dentry *lower_dir_dentry;
 412         u64 file_size_save;
 413         int rc;
 414
 415         file_size_save = i_size_read(old_dentry->d_inode);
 416         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 417         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 418         dget(lower_old_dentry);
 419         dget(lower_new_dentry);
 420         lower_dir_dentry = lock_parent(lower_new_dentry);
 421         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 422                       lower_new_dentry);
 423         if (rc || !lower_new_dentry->d_inode)
 424                 goto out_lock;
 425         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 426         if (rc)
 427                 goto out_lock;
 428         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 429         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 430         old_dentry->d_inode->i_nlink =
 431                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 432         i_size_write(new_dentry->d_inode, file_size_save);
 433 out_lock:
 434         unlock_dir(lower_dir_dentry);
 435         dput(lower_new_dentry);
 436         dput(lower_old_dentry);
 437         return rc;
 438 }
 439
 440 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 441 {
 442         int rc = 0;
 443         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 444         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 445         struct dentry *lower_dir_dentry;
 446
 447         dget(lower_dentry);
 448         lower_dir_dentry = lock_parent(lower_dentry);
 449         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 450         if (rc) {
 451                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 452                 goto out_unlock;
 453         }
 454         fsstack_copy_attr_times(dir, lower_dir_inode);
 455         dentry->d_inode->i_nlink =
 456                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 457         dentry->d_inode->i_ctime = dir->i_ctime;
 458         d_drop(dentry);
 459 out_unlock:
 460         unlock_dir(lower_dir_dentry);
 461         dput(lower_dentry);
 462         return rc;
 463 }
 464
 465 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 466                             const char *symname)
 467 {
 468         int rc;
 469         struct dentry *lower_dentry;
 470         struct dentry *lower_dir_dentry;
 471         char *encoded_symname;
 472         size_t encoded_symlen;
 473         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 474
 475         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 476         dget(lower_dentry);
 477         lower_dir_dentry = lock_parent(lower_dentry);
 478         mount_crypt_stat = &ecryptfs_superblock_to_private(
 479                 dir->i_sb)->mount_crypt_stat;
 480         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 481                                                   &encoded_symlen,
 482                                                   NULL,
 483                                                   mount_crypt_stat, symname,
 484                                                   strlen(symname));
 485         if (rc)
 486                 goto out_lock;
 487         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 488                          encoded_symname);
 489         kfree(encoded_symname);
 490         if (rc || !lower_dentry->d_inode)
 491                 goto out_lock;
 492         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 493         if (rc)
 494                 goto out_lock;
 495         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 496         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 497 out_lock:
 498         unlock_dir(lower_dir_dentry);
 499         dput(lower_dentry);
 500         if (!dentry->d_inode)
 501                 d_drop(dentry);
 502         return rc;
 503 }
 504
 505 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 506 {
 507         int rc;
 508         struct dentry *lower_dentry;
 509         struct dentry *lower_dir_dentry;
 510
 511         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 512         lower_dir_dentry = lock_parent(lower_dentry);
 513         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 514         if (rc || !lower_dentry->d_inode)
 515                 goto out;
 516         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 517         if (rc)
 518                 goto out;
 519         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 520         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 521         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 522 out:
 523         unlock_dir(lower_dir_dentry);
 524         if (!dentry->d_inode)
 525                 d_drop(dentry);
 526         return rc;
 527 }
 528
 529 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 530 {
 531         struct dentry *lower_dentry;
 532         struct dentry *lower_dir_dentry;
 533         int rc;
 534
 535         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 536         dget(dentry);
 537         lower_dir_dentry = lock_parent(lower_dentry);
 538         dget(lower_dentry);
 539         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 540         dput(lower_dentry);
 541         if (!rc)
 542                 d_delete(lower_dentry);
 543         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 544         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 545         unlock_dir(lower_dir_dentry);
 546         if (!rc)
 547                 d_drop(dentry);
 548         dput(dentry);
 549         return rc;
 550 }
 551
 552 static int
 553 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 554 {
 555         int rc;
 556         struct dentry *lower_dentry;
 557         struct dentry *lower_dir_dentry;
 558
 559         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 560         lower_dir_dentry = lock_parent(lower_dentry);
 561         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 562         if (rc || !lower_dentry->d_inode)
 563                 goto out;
 564         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 565         if (rc)
 566                 goto out;
 567         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 568         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 569 out:
 570         unlock_dir(lower_dir_dentry);
 571         if (!dentry->d_inode)
 572                 d_drop(dentry);
 573         return rc;
 574 }
 575
 576 static int
 577 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 578                 struct inode *new_dir, struct dentry *new_dentry)
 579 {
 580         int rc;
 581         struct dentry *lower_old_dentry;
 582         struct dentry *lower_new_dentry;
 583         struct dentry *lower_old_dir_dentry;
 584         struct dentry *lower_new_dir_dentry;
 585         struct dentry *trap = NULL;
 586
 587         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 588         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 589         dget(lower_old_dentry);
 590         dget(lower_new_dentry);
 591         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 592         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 593         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 594         /* source should not be ancestor of target */
 595         if (trap == lower_old_dentry) {
 596                 rc = -EINVAL;
 597                 goto out_lock;
 598         }
 599         /* target should not be ancestor of source */
 600         if (trap == lower_new_dentry) {
 601                 rc = -ENOTEMPTY;
 602                 goto out_lock;
 603         }
 604         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 605                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 606         if (rc)
 607                 goto out_lock;
 608         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
 609         if (new_dir != old_dir)
 610                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
 611 out_lock:
 612         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 613         dput(lower_new_dentry->d_parent);
 614         dput(lower_old_dentry->d_parent);
 615         dput(lower_new_dentry);
 616         dput(lower_old_dentry);
 617         return rc;
 618 }
 619
 620 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
 621                                    size_t *bufsiz)
 622 {
 623         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 624         char *lower_buf;
 625         size_t lower_bufsiz = PATH_MAX;
 626         mm_segment_t old_fs;
 627         int rc;
 628
 629         lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
 630         if (!lower_buf) {
 631                 rc = -ENOMEM;
 632                 goto out;
 633         }
 634         old_fs = get_fs();
 635         set_fs(get_ds());
 636         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 637                                                    (char __user *)lower_buf,
 638                                                    lower_bufsiz);
 639         set_fs(old_fs);
 640         if (rc < 0)
 641                 goto out;
 642         lower_bufsiz = rc;
 643         rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
 644                                                   lower_buf, lower_bufsiz);
 645 out:
 646         kfree(lower_buf);
 647         return rc;
 648 }
 649
 650 static int
 651 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
 652 {
 653         char *kbuf;
 654         size_t kbufsiz, copied;
 655         int rc;
 656
 657         rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
 658         if (rc)
 659                 goto out;
 660         copied = min_t(size_t, bufsiz, kbufsiz);
 661         rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
 662         kfree(kbuf);
 663         fsstack_copy_attr_atime(dentry->d_inode,
 664                                 ecryptfs_dentry_to_lower(dentry)->d_inode);
 665 out:
 666         return rc;
 667 }
 668
 669 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 670 {
 671         char *buf;
 672         int len = PAGE_SIZE, rc;
 673         mm_segment_t old_fs;
 674
 675         /* Released in ecryptfs_put_link(); only release here on error */
 676         buf = kmalloc(len, GFP_KERNEL);
 677         if (!buf) {
 678                 buf = ERR_PTR(-ENOMEM);
 679                 goto out;
 680         }
 681         old_fs = get_fs();
 682         set_fs(get_ds());
 683         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 684         set_fs(old_fs);
 685         if (rc < 0) {
 686                 kfree(buf);
 687                 buf = ERR_PTR(rc);
 688         } else
 689                 buf[rc] = '\0';
 690 out:
 691         nd_set_link(nd, buf);
 692         return NULL;
 693 }
 694
 695 static void
 696 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 697 {
 698         char *buf = nd_get_link(nd);
 699         if (!IS_ERR(buf)) {
 700                 /* Free the char* */
 701                 kfree(buf);
 702         }
 703 }
 704
 705 /**
 706  * upper_size_to_lower_size
 707  * @crypt_stat: Crypt_stat associated with file
 708  * @upper_size: Size of the upper file
 709  *
 710  * Calculate the required size of the lower file based on the
 711  * specified size of the upper file. This calculation is based on the
 712  * number of headers in the underlying file and the extent size.
 713  *
 714  * Returns Calculated size of the lower file.
 715  */
 716 static loff_t
 717 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 718                          loff_t upper_size)
 719 {
 720         loff_t lower_size;
 721
 722         lower_size = ecryptfs_lower_header_size(crypt_stat);
 723         if (upper_size != 0) {
 724                 loff_t num_extents;
 725
 726                 num_extents = upper_size >> crypt_stat->extent_shift;
 727                 if (upper_size & ~crypt_stat->extent_mask)
 728                         num_extents++;
 729                 lower_size += (num_extents * crypt_stat->extent_size);
 730         }
 731         return lower_size;
 732 }
 733
 734 /**
 735  * truncate_upper
 736  * @dentry: The ecryptfs layer dentry
 737  * @ia: Address of the ecryptfs inode's attributes
 738  * @lower_ia: Address of the lower inode's attributes
 739  *
 740  * Function to handle truncations modifying the size of the file. Note
 741  * that the file sizes are interpolated. When expanding, we are simply
 742  * writing strings of 0's out. When truncating, we truncate the upper
 743  * inode and update the lower_ia according to the page index
 744  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 745  * the caller must use lower_ia in a call to notify_change() to perform
 746  * the truncation of the lower inode.
 747  *
 748  * Returns zero on success; non-zero otherwise
 749  */
 750 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 751                           struct iattr *lower_ia)
 752 {
 753         int rc = 0;
 754         struct inode *inode = dentry->d_inode;
 755         struct ecryptfs_crypt_stat *crypt_stat;
 756         loff_t i_size = i_size_read(inode);
 757         loff_t lower_size_before_truncate;
 758         loff_t lower_size_after_truncate;
 759
 760         if (unlikely((ia->ia_size == i_size))) {
 761                 lower_ia->ia_valid &= ~ATTR_SIZE;
 762                 goto out;
 763         }
 764         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 765         /* Switch on growing or shrinking file */
 766         if (ia->ia_size > i_size) {
 767                 char zero[] = { 0x00 };
 768
 769                 lower_ia->ia_valid &= ~ATTR_SIZE;
 770                 /* Write a single 0 at the last position of the file;
 771                  * this triggers code that will fill in 0's throughout
 772                  * the intermediate portion of the previous end of the
 773                  * file and the new and of the file */
 774                 rc = ecryptfs_write(inode, zero,
 775                                     (ia->ia_size - 1), 1);
 776         } else { /* ia->ia_size < i_size_read(inode) */
 777                 /* We're chopping off all the pages down to the page
 778                  * in which ia->ia_size is located. Fill in the end of
 779                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
 780                  * PAGE_CACHE_SIZE with zeros. */
 781                 size_t num_zeros = (PAGE_CACHE_SIZE
 782                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
 783
 784
 785                 /*
 786                  * XXX(truncate) this should really happen at the begginning
 787                  * of ->setattr.  But the code is too messy to that as part
 788                  * of a larger patch.  ecryptfs is also totally missing out
 789                  * on the inode_change_ok check at the beginning of
 790                  * ->setattr while would include this.
 791                  */
 792                 rc = inode_newsize_ok(inode, ia->ia_size);
 793                 if (rc)
 794                         goto out;
 795
 796                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 797                         truncate_setsize(inode, ia->ia_size);
 798                         lower_ia->ia_size = ia->ia_size;
 799                         lower_ia->ia_valid |= ATTR_SIZE;
 800                         goto out;
 801                 }
 802                 if (num_zeros) {
 803                         char *zeros_virt;
 804
 805                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 806                         if (!zeros_virt) {
 807                                 rc = -ENOMEM;
 808                                 goto out;
 809                         }
 810                         rc = ecryptfs_write(inode, zeros_virt,
 811                                             ia->ia_size, num_zeros);
 812                         kfree(zeros_virt);
 813                         if (rc) {
 814                                 printk(KERN_ERR "Error attempting to zero out "
 815                                        "the remainder of the end page on "
 816                                        "reducing truncate; rc = [%d]\n", rc);
 817                                 goto out;
 818                         }
 819                 }
 820                 truncate_setsize(inode, ia->ia_size);
 821                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 822                 if (rc) {
 823                         printk(KERN_ERR "Problem with "
 824                                "ecryptfs_write_inode_size_to_metadata; "
 825                                "rc = [%d]\n", rc);
 826                         goto out;
 827                 }
 828                 /* We are reducing the size of the ecryptfs file, and need to
 829                  * know if we need to reduce the size of the lower file. */
 830                 lower_size_before_truncate =
 831                     upper_size_to_lower_size(crypt_stat, i_size);
 832                 lower_size_after_truncate =
 833                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 834                 if (lower_size_after_truncate < lower_size_before_truncate) {
 835                         lower_ia->ia_size = lower_size_after_truncate;
 836                         lower_ia->ia_valid |= ATTR_SIZE;
 837                 } else
 838                         lower_ia->ia_valid &= ~ATTR_SIZE;
 839         }
 840 out:
 841         return rc;
 842 }
 843
 844 /**
 845  * ecryptfs_truncate
 846  * @dentry: The ecryptfs layer dentry
 847  * @new_length: The length to expand the file to
 848  *
 849  * Simple function that handles the truncation of an eCryptfs inode and
 850  * its corresponding lower inode.
 851  *
 852  * Returns zero on success; non-zero otherwise
 853  */
 854 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 855 {
 856         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 857         struct iattr lower_ia = { .ia_valid = 0 };
 858         int rc;
 859
 860         rc = truncate_upper(dentry, &ia, &lower_ia);
 861         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 862                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 863
 864                 mutex_lock(&lower_dentry->d_inode->i_mutex);
 865                 rc = notify_change(lower_dentry, &lower_ia);
 866                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
 867         }
 868         return rc;
 869 }
 870
 871 static int
 872 ecryptfs_permission(struct inode *inode, int mask, unsigned int flags)
 873 {
 874         if (flags & IPERM_FLAG_RCU)
 875                 return -ECHILD;
 876         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 877 }
 878
 879 /**
 880  * ecryptfs_setattr
 881  * @dentry: dentry handle to the inode to modify
 882  * @ia: Structure with flags of what to change and values
 883  *
 884  * Updates the metadata of an inode. If the update is to the size
 885  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 886  * of both the ecryptfs inode and the lower inode.
 887  *
 888  * All other metadata changes will be passed right to the lower filesystem,
 889  * and we will just update our inode to look like the lower.
 890  */
 891 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 892 {
 893         int rc = 0;
 894         struct dentry *lower_dentry;
 895         struct iattr lower_ia;
 896         struct inode *inode;
 897         struct inode *lower_inode;
 898         struct ecryptfs_crypt_stat *crypt_stat;
 899
 900         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 901         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 902                 ecryptfs_init_crypt_stat(crypt_stat);
 903         inode = dentry->d_inode;
 904         lower_inode = ecryptfs_inode_to_lower(inode);
 905         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 906         mutex_lock(&crypt_stat->cs_mutex);
 907         if (S_ISDIR(dentry->d_inode->i_mode))
 908                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 909         else if (S_ISREG(dentry->d_inode->i_mode)
 910                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 911                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 912                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 913
 914                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 915                         dentry->d_sb)->mount_crypt_stat;
 916                 rc = ecryptfs_read_metadata(dentry);
 917                 if (rc) {
 918                         if (!(mount_crypt_stat->flags
 919                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 920                                 rc = -EIO;
 921                                 printk(KERN_WARNING "Either the lower file "
 922                                        "is not in a valid eCryptfs format, "
 923                                        "or the key could not be retrieved. "
 924                                        "Plaintext passthrough mode is not "
 925                                        "enabled; returning -EIO\n");
 926                                 mutex_unlock(&crypt_stat->cs_mutex);
 927                                 goto out;
 928                         }
 929                         rc = 0;
 930                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 931                 }
 932         }
 933         mutex_unlock(&crypt_stat->cs_mutex);
 934         memcpy(&lower_ia, ia, sizeof(lower_ia));
 935         if (ia->ia_valid & ATTR_FILE)
 936                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 937         if (ia->ia_valid & ATTR_SIZE) {
 938                 rc = truncate_upper(dentry, ia, &lower_ia);
 939                 if (rc < 0)
 940                         goto out;
 941         }
 942
 943         /*
 944          * mode change is for clearing setuid/setgid bits. Allow lower fs
 945          * to interpret this in its own way.
 946          */
 947         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 948                 lower_ia.ia_valid &= ~ATTR_MODE;
 949
 950         mutex_lock(&lower_dentry->d_inode->i_mutex);
 951         rc = notify_change(lower_dentry, &lower_ia);
 952         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 953 out:
 954         fsstack_copy_attr_all(inode, lower_inode);
 955         return rc;
 956 }
 957
 958 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
 959                           struct kstat *stat)
 960 {
 961         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 962         int rc = 0;
 963
 964         mount_crypt_stat = &ecryptfs_superblock_to_private(
 965                                                 dentry->d_sb)->mount_crypt_stat;
 966         generic_fillattr(dentry->d_inode, stat);
 967         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 968                 char *target;
 969                 size_t targetsiz;
 970
 971                 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
 972                 if (!rc) {
 973                         kfree(target);
 974                         stat->size = targetsiz;
 975                 }
 976         }
 977         return rc;
 978 }
 979
 980 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 981                      struct kstat *stat)
 982 {
 983         struct kstat lower_stat;
 984         int rc;
 985
 986         rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
 987                          ecryptfs_dentry_to_lower(dentry), &lower_stat);
 988         if (!rc) {
 989                 fsstack_copy_attr_all(dentry->d_inode,
 990                                       ecryptfs_inode_to_lower(dentry->d_inode));
 991                 generic_fillattr(dentry->d_inode, stat);
 992                 stat->blocks = lower_stat.blocks;
 993         }
 994         return rc;
 995 }
 996
 997 int
 998 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 999                   size_t size, int flags)
1000 {
1001         int rc = 0;
1002         struct dentry *lower_dentry;
1003
1004         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1005         if (!lower_dentry->d_inode->i_op->setxattr) {
1006                 rc = -EOPNOTSUPP;
1007                 goto out;
1008         }
1009
1010         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1011 out:
1012         return rc;
1013 }
1014
1015 ssize_t
1016 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1017                         void *value, size_t size)
1018 {
1019         int rc = 0;
1020
1021         if (!lower_dentry->d_inode->i_op->getxattr) {
1022                 rc = -EOPNOTSUPP;
1023                 goto out;
1024         }
1025         mutex_lock(&lower_dentry->d_inode->i_mutex);
1026         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1027                                                    size);
1028         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1029 out:
1030         return rc;
1031 }
1032
1033 static ssize_t
1034 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1035                   size_t size)
1036 {
1037         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1038                                        value, size);
1039 }
1040
1041 static ssize_t
1042 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1043 {
1044         int rc = 0;
1045         struct dentry *lower_dentry;
1046
1047         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1048         if (!lower_dentry->d_inode->i_op->listxattr) {
1049                 rc = -EOPNOTSUPP;
1050                 goto out;
1051         }
1052         mutex_lock(&lower_dentry->d_inode->i_mutex);
1053         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1054         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1055 out:
1056         return rc;
1057 }
1058
1059 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1060 {
1061         int rc = 0;
1062         struct dentry *lower_dentry;
1063
1064         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1065         if (!lower_dentry->d_inode->i_op->removexattr) {
1066                 rc = -EOPNOTSUPP;
1067                 goto out;
1068         }
1069         mutex_lock(&lower_dentry->d_inode->i_mutex);
1070         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1071         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1072 out:
1073         return rc;
1074 }
1075
1076 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1077 {
1078         if ((ecryptfs_inode_to_lower(inode)
1079              == (struct inode *)candidate_lower_inode))
1080                 return 1;
1081         else
1082                 return 0;
1083 }
1084
1085 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1086 {
1087         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1088         return 0;
1089 }
1090
1091 const struct inode_operations ecryptfs_symlink_iops = {
1092         .readlink = ecryptfs_readlink,
1093         .follow_link = ecryptfs_follow_link,
1094         .put_link = ecryptfs_put_link,
1095         .permission = ecryptfs_permission,
1096         .setattr = ecryptfs_setattr,
1097         .getattr = ecryptfs_getattr_link,
1098         .setxattr = ecryptfs_setxattr,
1099         .getxattr = ecryptfs_getxattr,
1100         .listxattr = ecryptfs_listxattr,
1101         .removexattr = ecryptfs_removexattr
1102 };
1103
1104 const struct inode_operations ecryptfs_dir_iops = {
1105         .create = ecryptfs_create,
1106         .lookup = ecryptfs_lookup,
1107         .link = ecryptfs_link,
1108         .unlink = ecryptfs_unlink,
1109         .symlink = ecryptfs_symlink,
1110         .mkdir = ecryptfs_mkdir,
1111         .rmdir = ecryptfs_rmdir,
1112         .mknod = ecryptfs_mknod,
1113         .rename = ecryptfs_rename,
1114         .permission = ecryptfs_permission,
1115         .setattr = ecryptfs_setattr,
1116         .setxattr = ecryptfs_setxattr,
1117         .getxattr = ecryptfs_getxattr,
1118         .listxattr = ecryptfs_listxattr,
1119         .removexattr = ecryptfs_removexattr
1120 };
1121
1122 const struct inode_operations ecryptfs_main_iops = {
1123         .permission = ecryptfs_permission,
1124         .setattr = ecryptfs_setattr,
1125         .getattr = ecryptfs_getattr,
1126         .setxattr = ecryptfs_setxattr,
1127         .getxattr = ecryptfs_getxattr,
1128         .listxattr = ecryptfs_listxattr,
1129         .removexattr = ecryptfs_removexattr
1130 };