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 <[email protected]>
   8  *              Michael C. Thompsion <[email protected]>
   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(&(d_inode(dir)->i_mutex), I_MUTEX_PARENT);
  45         return dir;
  46 }
  47
  48 static void unlock_dir(struct dentry *dir)
  49 {
  50         mutex_unlock(&d_inode(dir)->i_mutex);
  51         dput(dir);
  52 }
  53
  54 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
  55 {
  56         return ecryptfs_inode_to_lower(inode) == lower_inode;
  57 }
  58
  59 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
  60 {
  61         struct inode *lower_inode = opaque;
  62
  63         ecryptfs_set_inode_lower(inode, lower_inode);
  64         fsstack_copy_attr_all(inode, lower_inode);
  65         /* i_size will be overwritten for encrypted regular files */
  66         fsstack_copy_inode_size(inode, lower_inode);
  67         inode->i_ino = lower_inode->i_ino;
  68         inode->i_version++;
  69         inode->i_mapping->a_ops = &ecryptfs_aops;
  70
  71         if (S_ISLNK(inode->i_mode))
  72                 inode->i_op = &ecryptfs_symlink_iops;
  73         else if (S_ISDIR(inode->i_mode))
  74                 inode->i_op = &ecryptfs_dir_iops;
  75         else
  76                 inode->i_op = &ecryptfs_main_iops;
  77
  78         if (S_ISDIR(inode->i_mode))
  79                 inode->i_fop = &ecryptfs_dir_fops;
  80         else if (special_file(inode->i_mode))
  81                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
  82         else
  83                 inode->i_fop = &ecryptfs_main_fops;
  84
  85         return 0;
  86 }
  87
  88 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  89                                           struct super_block *sb)
  90 {
  91         struct inode *inode;
  92
  93         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  94                 return ERR_PTR(-EXDEV);
  95         if (!igrab(lower_inode))
  96                 return ERR_PTR(-ESTALE);
  97         inode = iget5_locked(sb, (unsigned long)lower_inode,
  98                              ecryptfs_inode_test, ecryptfs_inode_set,
  99                              lower_inode);
 100         if (!inode) {
 101                 iput(lower_inode);
 102                 return ERR_PTR(-EACCES);
 103         }
 104         if (!(inode->i_state & I_NEW))
 105                 iput(lower_inode);
 106
 107         return inode;
 108 }
 109
 110 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 111                                  struct super_block *sb)
 112 {
 113         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 114
 115         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 116                 unlock_new_inode(inode);
 117
 118         return inode;
 119 }
 120
 121 /**
 122  * ecryptfs_interpose
 123  * @lower_dentry: Existing dentry in the lower filesystem
 124  * @dentry: ecryptfs' dentry
 125  * @sb: ecryptfs's super_block
 126  *
 127  * Interposes upper and lower dentries.
 128  *
 129  * Returns zero on success; non-zero otherwise
 130  */
 131 static int ecryptfs_interpose(struct dentry *lower_dentry,
 132                               struct dentry *dentry, struct super_block *sb)
 133 {
 134         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 135
 136         if (IS_ERR(inode))
 137                 return PTR_ERR(inode);
 138         d_instantiate(dentry, inode);
 139
 140         return 0;
 141 }
 142
 143 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 144                               struct inode *inode)
 145 {
 146         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 147         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 148         struct dentry *lower_dir_dentry;
 149         int rc;
 150
 151         dget(lower_dentry);
 152         lower_dir_dentry = lock_parent(lower_dentry);
 153         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 154         if (rc) {
 155                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 156                 goto out_unlock;
 157         }
 158         fsstack_copy_attr_times(dir, lower_dir_inode);
 159         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 160         inode->i_ctime = dir->i_ctime;
 161         d_drop(dentry);
 162 out_unlock:
 163         unlock_dir(lower_dir_dentry);
 164         dput(lower_dentry);
 165         return rc;
 166 }
 167
 168 /**
 169  * ecryptfs_do_create
 170  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 171  * @ecryptfs_dentry: New file's dentry in ecryptfs
 172  * @mode: The mode of the new file
 173  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 174  *
 175  * Creates the underlying file and the eCryptfs inode which will link to
 176  * it. It will also update the eCryptfs directory inode to mimic the
 177  * stat of the lower directory inode.
 178  *
 179  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 180  */
 181 static struct inode *
 182 ecryptfs_do_create(struct inode *directory_inode,
 183                    struct dentry *ecryptfs_dentry, umode_t mode)
 184 {
 185         int rc;
 186         struct dentry *lower_dentry;
 187         struct dentry *lower_dir_dentry;
 188         struct inode *inode;
 189
 190         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 191         lower_dir_dentry = lock_parent(lower_dentry);
 192         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 193         if (rc) {
 194                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 195                        "rc = [%d]\n", __func__, rc);
 196                 inode = ERR_PTR(rc);
 197                 goto out_lock;
 198         }
 199         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 200                                      directory_inode->i_sb);
 201         if (IS_ERR(inode)) {
 202                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 203                 goto out_lock;
 204         }
 205         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 206         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 207 out_lock:
 208         unlock_dir(lower_dir_dentry);
 209         return inode;
 210 }
 211
 212 /**
 213  * ecryptfs_initialize_file
 214  *
 215  * Cause the file to be changed from a basic empty file to an ecryptfs
 216  * file with a header and first data page.
 217  *
 218  * Returns zero on success
 219  */
 220 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 221                              struct inode *ecryptfs_inode)
 222 {
 223         struct ecryptfs_crypt_stat *crypt_stat =
 224                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 225         int rc = 0;
 226
 227         if (S_ISDIR(ecryptfs_inode->i_mode)) {
 228                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 229                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 230                 goto out;
 231         }
 232         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 233         rc = ecryptfs_new_file_context(ecryptfs_inode);
 234         if (rc) {
 235                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 236                                 "context; rc = [%d]\n", rc);
 237                 goto out;
 238         }
 239         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 240         if (rc) {
 241                 printk(KERN_ERR "%s: Error attempting to initialize "
 242                         "the lower file for the dentry with name "
 243                         "[%pd]; rc = [%d]\n", __func__,
 244                         ecryptfs_dentry, rc);
 245                 goto out;
 246         }
 247         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 248         if (rc)
 249                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 250         ecryptfs_put_lower_file(ecryptfs_inode);
 251 out:
 252         return rc;
 253 }
 254
 255 /**
 256  * ecryptfs_create
 257  * @dir: The inode of the directory in which to create the file.
 258  * @dentry: The eCryptfs dentry
 259  * @mode: The mode of the new file.
 260  *
 261  * Creates a new file.
 262  *
 263  * Returns zero on success; non-zero on error condition
 264  */
 265 static int
 266 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 267                 umode_t mode, bool excl)
 268 {
 269         struct inode *ecryptfs_inode;
 270         int rc;
 271
 272         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 273                                             mode);
 274         if (unlikely(IS_ERR(ecryptfs_inode))) {
 275                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 276                                 "lower filesystem\n");
 277                 rc = PTR_ERR(ecryptfs_inode);
 278                 goto out;
 279         }
 280         /* At this point, a file exists on "disk"; we need to make sure
 281          * that this on disk file is prepared to be an ecryptfs file */
 282         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 283         if (rc) {
 284                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 285                                    ecryptfs_inode);
 286                 make_bad_inode(ecryptfs_inode);
 287                 unlock_new_inode(ecryptfs_inode);
 288                 iput(ecryptfs_inode);
 289                 goto out;
 290         }
 291         unlock_new_inode(ecryptfs_inode);
 292         d_instantiate(ecryptfs_dentry, ecryptfs_inode);
 293 out:
 294         return rc;
 295 }
 296
 297 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 298 {
 299         struct ecryptfs_crypt_stat *crypt_stat;
 300         int rc;
 301
 302         rc = ecryptfs_get_lower_file(dentry, inode);
 303         if (rc) {
 304                 printk(KERN_ERR "%s: Error attempting to initialize "
 305                         "the lower file for the dentry with name "
 306                         "[%pd]; rc = [%d]\n", __func__,
 307                         dentry, rc);
 308                 return rc;
 309         }
 310
 311         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 312         /* TODO: lock for crypt_stat comparison */
 313         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 314                 ecryptfs_set_default_sizes(crypt_stat);
 315
 316         rc = ecryptfs_read_and_validate_header_region(inode);
 317         ecryptfs_put_lower_file(inode);
 318         if (rc) {
 319                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
 320                 if (!rc)
 321                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 322         }
 323
 324         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
 325         return 0;
 326 }
 327
 328 /**
 329  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 330  */
 331 static int ecryptfs_lookup_interpose(struct dentry *dentry,
 332                                      struct dentry *lower_dentry,
 333                                      struct inode *dir_inode)
 334 {
 335         struct inode *inode, *lower_inode = d_inode(lower_dentry);
 336         struct ecryptfs_dentry_info *dentry_info;
 337         struct vfsmount *lower_mnt;
 338         int rc = 0;
 339
 340         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 341         if (!dentry_info) {
 342                 printk(KERN_ERR "%s: Out of memory whilst attempting "
 343                        "to allocate ecryptfs_dentry_info struct\n",
 344                         __func__);
 345                 dput(lower_dentry);
 346                 return -ENOMEM;
 347         }
 348
 349         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 350         fsstack_copy_attr_atime(dir_inode, d_inode(lower_dentry->d_parent));
 351         BUG_ON(!d_count(lower_dentry));
 352
 353         ecryptfs_set_dentry_private(dentry, dentry_info);
 354         dentry_info->lower_path.mnt = lower_mnt;
 355         dentry_info->lower_path.dentry = lower_dentry;
 356
 357         if (d_really_is_negative(lower_dentry)) {
 358                 /* We want to add because we couldn't find in lower */
 359                 d_add(dentry, NULL);
 360                 return 0;
 361         }
 362         inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
 363         if (IS_ERR(inode)) {
 364                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 365                        __func__, PTR_ERR(inode));
 366                 return PTR_ERR(inode);
 367         }
 368         if (S_ISREG(inode->i_mode)) {
 369                 rc = ecryptfs_i_size_read(dentry, inode);
 370                 if (rc) {
 371                         make_bad_inode(inode);
 372                         return rc;
 373                 }
 374         }
 375
 376         if (inode->i_state & I_NEW)
 377                 unlock_new_inode(inode);
 378         d_add(dentry, inode);
 379
 380         return rc;
 381 }
 382
 383 /**
 384  * ecryptfs_lookup
 385  * @ecryptfs_dir_inode: The eCryptfs directory inode
 386  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 387  * @ecryptfs_nd: nameidata; may be NULL
 388  *
 389  * Find a file on disk. If the file does not exist, then we'll add it to the
 390  * dentry cache and continue on to read it from the disk.
 391  */
 392 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 393                                       struct dentry *ecryptfs_dentry,
 394                                       unsigned int flags)
 395 {
 396         char *encrypted_and_encoded_name = NULL;
 397         size_t encrypted_and_encoded_name_size;
 398         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 399         struct dentry *lower_dir_dentry, *lower_dentry;
 400         int rc = 0;
 401
 402         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 403         mutex_lock(&d_inode(lower_dir_dentry)->i_mutex);
 404         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
 405                                       lower_dir_dentry,
 406                                       ecryptfs_dentry->d_name.len);
 407         mutex_unlock(&d_inode(lower_dir_dentry)->i_mutex);
 408         if (IS_ERR(lower_dentry)) {
 409                 rc = PTR_ERR(lower_dentry);
 410                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 411                                 "[%d] on lower_dentry = [%pd]\n", __func__, rc,
 412                                 ecryptfs_dentry);
 413                 goto out;
 414         }
 415         if (d_really_is_positive(lower_dentry))
 416                 goto interpose;
 417         mount_crypt_stat = &ecryptfs_superblock_to_private(
 418                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 419         if (!(mount_crypt_stat
 420             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
 421                 goto interpose;
 422         dput(lower_dentry);
 423         rc = ecryptfs_encrypt_and_encode_filename(
 424                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
 425                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
 426                 ecryptfs_dentry->d_name.len);
 427         if (rc) {
 428                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 429                        "filename; rc = [%d]\n", __func__, rc);
 430                 goto out;
 431         }
 432         mutex_lock(&d_inode(lower_dir_dentry)->i_mutex);
 433         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
 434                                       lower_dir_dentry,
 435                                       encrypted_and_encoded_name_size);
 436         mutex_unlock(&d_inode(lower_dir_dentry)->i_mutex);
 437         if (IS_ERR(lower_dentry)) {
 438                 rc = PTR_ERR(lower_dentry);
 439                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 440                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
 441                                 encrypted_and_encoded_name);
 442                 goto out;
 443         }
 444 interpose:
 445         rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
 446                                        ecryptfs_dir_inode);
 447 out:
 448         kfree(encrypted_and_encoded_name);
 449         return ERR_PTR(rc);
 450 }
 451
 452 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 453                          struct dentry *new_dentry)
 454 {
 455         struct dentry *lower_old_dentry;
 456         struct dentry *lower_new_dentry;
 457         struct dentry *lower_dir_dentry;
 458         u64 file_size_save;
 459         int rc;
 460
 461         file_size_save = i_size_read(d_inode(old_dentry));
 462         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 463         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 464         dget(lower_old_dentry);
 465         dget(lower_new_dentry);
 466         lower_dir_dentry = lock_parent(lower_new_dentry);
 467         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 468                       lower_new_dentry, NULL);
 469         if (rc || d_really_is_negative(lower_new_dentry))
 470                 goto out_lock;
 471         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 472         if (rc)
 473                 goto out_lock;
 474         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 475         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 476         set_nlink(d_inode(old_dentry),
 477                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 478         i_size_write(d_inode(new_dentry), file_size_save);
 479 out_lock:
 480         unlock_dir(lower_dir_dentry);
 481         dput(lower_new_dentry);
 482         dput(lower_old_dentry);
 483         return rc;
 484 }
 485
 486 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 487 {
 488         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 489 }
 490
 491 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 492                             const char *symname)
 493 {
 494         int rc;
 495         struct dentry *lower_dentry;
 496         struct dentry *lower_dir_dentry;
 497         char *encoded_symname;
 498         size_t encoded_symlen;
 499         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 500
 501         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 502         dget(lower_dentry);
 503         lower_dir_dentry = lock_parent(lower_dentry);
 504         mount_crypt_stat = &ecryptfs_superblock_to_private(
 505                 dir->i_sb)->mount_crypt_stat;
 506         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 507                                                   &encoded_symlen,
 508                                                   NULL,
 509                                                   mount_crypt_stat, symname,
 510                                                   strlen(symname));
 511         if (rc)
 512                 goto out_lock;
 513         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 514                          encoded_symname);
 515         kfree(encoded_symname);
 516         if (rc || d_really_is_negative(lower_dentry))
 517                 goto out_lock;
 518         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 519         if (rc)
 520                 goto out_lock;
 521         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 522         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 523 out_lock:
 524         unlock_dir(lower_dir_dentry);
 525         dput(lower_dentry);
 526         if (d_really_is_negative(dentry))
 527                 d_drop(dentry);
 528         return rc;
 529 }
 530
 531 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 532 {
 533         int rc;
 534         struct dentry *lower_dentry;
 535         struct dentry *lower_dir_dentry;
 536
 537         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 538         lower_dir_dentry = lock_parent(lower_dentry);
 539         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 540         if (rc || d_really_is_negative(lower_dentry))
 541                 goto out;
 542         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 543         if (rc)
 544                 goto out;
 545         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 546         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 547         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 548 out:
 549         unlock_dir(lower_dir_dentry);
 550         if (d_really_is_negative(dentry))
 551                 d_drop(dentry);
 552         return rc;
 553 }
 554
 555 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 556 {
 557         struct dentry *lower_dentry;
 558         struct dentry *lower_dir_dentry;
 559         int rc;
 560
 561         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 562         dget(dentry);
 563         lower_dir_dentry = lock_parent(lower_dentry);
 564         dget(lower_dentry);
 565         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 566         dput(lower_dentry);
 567         if (!rc && d_really_is_positive(dentry))
 568                 clear_nlink(d_inode(dentry));
 569         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 570         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 571         unlock_dir(lower_dir_dentry);
 572         if (!rc)
 573                 d_drop(dentry);
 574         dput(dentry);
 575         return rc;
 576 }
 577
 578 static int
 579 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 580 {
 581         int rc;
 582         struct dentry *lower_dentry;
 583         struct dentry *lower_dir_dentry;
 584
 585         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 586         lower_dir_dentry = lock_parent(lower_dentry);
 587         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 588         if (rc || d_really_is_negative(lower_dentry))
 589                 goto out;
 590         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 591         if (rc)
 592                 goto out;
 593         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 594         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 595 out:
 596         unlock_dir(lower_dir_dentry);
 597         if (d_really_is_negative(dentry))
 598                 d_drop(dentry);
 599         return rc;
 600 }
 601
 602 static int
 603 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 604                 struct inode *new_dir, struct dentry *new_dentry)
 605 {
 606         int rc;
 607         struct dentry *lower_old_dentry;
 608         struct dentry *lower_new_dentry;
 609         struct dentry *lower_old_dir_dentry;
 610         struct dentry *lower_new_dir_dentry;
 611         struct dentry *trap = NULL;
 612         struct inode *target_inode;
 613
 614         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 615         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 616         dget(lower_old_dentry);
 617         dget(lower_new_dentry);
 618         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 619         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 620         target_inode = d_inode(new_dentry);
 621         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 622         /* source should not be ancestor of target */
 623         if (trap == lower_old_dentry) {
 624                 rc = -EINVAL;
 625                 goto out_lock;
 626         }
 627         /* target should not be ancestor of source */
 628         if (trap == lower_new_dentry) {
 629                 rc = -ENOTEMPTY;
 630                 goto out_lock;
 631         }
 632         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 633                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 634                         NULL, 0);
 635         if (rc)
 636                 goto out_lock;
 637         if (target_inode)
 638                 fsstack_copy_attr_all(target_inode,
 639                                       ecryptfs_inode_to_lower(target_inode));
 640         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 641         if (new_dir != old_dir)
 642                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 643 out_lock:
 644         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 645         dput(lower_new_dir_dentry);
 646         dput(lower_old_dir_dentry);
 647         dput(lower_new_dentry);
 648         dput(lower_old_dentry);
 649         return rc;
 650 }
 651
 652 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 653 {
 654         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 655         char *lower_buf;
 656         char *buf;
 657         mm_segment_t old_fs;
 658         int rc;
 659
 660         lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
 661         if (!lower_buf)
 662                 return ERR_PTR(-ENOMEM);
 663         old_fs = get_fs();
 664         set_fs(get_ds());
 665         rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
 666                                                    (char __user *)lower_buf,
 667                                                    PATH_MAX);
 668         set_fs(old_fs);
 669         if (rc < 0)
 670                 goto out;
 671         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 672                                                   lower_buf, rc);
 673 out:
 674         kfree(lower_buf);
 675         return rc ? ERR_PTR(rc) : buf;
 676 }
 677
 678 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 679 {
 680         size_t len;
 681         char *buf = ecryptfs_readlink_lower(dentry, &len);
 682         if (IS_ERR(buf))
 683                 goto out;
 684         fsstack_copy_attr_atime(d_inode(dentry),
 685                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 686         buf[len] = '\0';
 687 out:
 688         nd_set_link(nd, buf);
 689         return NULL;
 690 }
 691
 692 /**
 693  * upper_size_to_lower_size
 694  * @crypt_stat: Crypt_stat associated with file
 695  * @upper_size: Size of the upper file
 696  *
 697  * Calculate the required size of the lower file based on the
 698  * specified size of the upper file. This calculation is based on the
 699  * number of headers in the underlying file and the extent size.
 700  *
 701  * Returns Calculated size of the lower file.
 702  */
 703 static loff_t
 704 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 705                          loff_t upper_size)
 706 {
 707         loff_t lower_size;
 708
 709         lower_size = ecryptfs_lower_header_size(crypt_stat);
 710         if (upper_size != 0) {
 711                 loff_t num_extents;
 712
 713                 num_extents = upper_size >> crypt_stat->extent_shift;
 714                 if (upper_size & ~crypt_stat->extent_mask)
 715                         num_extents++;
 716                 lower_size += (num_extents * crypt_stat->extent_size);
 717         }
 718         return lower_size;
 719 }
 720
 721 /**
 722  * truncate_upper
 723  * @dentry: The ecryptfs layer dentry
 724  * @ia: Address of the ecryptfs inode's attributes
 725  * @lower_ia: Address of the lower inode's attributes
 726  *
 727  * Function to handle truncations modifying the size of the file. Note
 728  * that the file sizes are interpolated. When expanding, we are simply
 729  * writing strings of 0's out. When truncating, we truncate the upper
 730  * inode and update the lower_ia according to the page index
 731  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 732  * the caller must use lower_ia in a call to notify_change() to perform
 733  * the truncation of the lower inode.
 734  *
 735  * Returns zero on success; non-zero otherwise
 736  */
 737 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 738                           struct iattr *lower_ia)
 739 {
 740         int rc = 0;
 741         struct inode *inode = d_inode(dentry);
 742         struct ecryptfs_crypt_stat *crypt_stat;
 743         loff_t i_size = i_size_read(inode);
 744         loff_t lower_size_before_truncate;
 745         loff_t lower_size_after_truncate;
 746
 747         if (unlikely((ia->ia_size == i_size))) {
 748                 lower_ia->ia_valid &= ~ATTR_SIZE;
 749                 return 0;
 750         }
 751         rc = ecryptfs_get_lower_file(dentry, inode);
 752         if (rc)
 753                 return rc;
 754         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 755         /* Switch on growing or shrinking file */
 756         if (ia->ia_size > i_size) {
 757                 char zero[] = { 0x00 };
 758
 759                 lower_ia->ia_valid &= ~ATTR_SIZE;
 760                 /* Write a single 0 at the last position of the file;
 761                  * this triggers code that will fill in 0's throughout
 762                  * the intermediate portion of the previous end of the
 763                  * file and the new and of the file */
 764                 rc = ecryptfs_write(inode, zero,
 765                                     (ia->ia_size - 1), 1);
 766         } else { /* ia->ia_size < i_size_read(inode) */
 767                 /* We're chopping off all the pages down to the page
 768                  * in which ia->ia_size is located. Fill in the end of
 769                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
 770                  * PAGE_CACHE_SIZE with zeros. */
 771                 size_t num_zeros = (PAGE_CACHE_SIZE
 772                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
 773
 774                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 775                         truncate_setsize(inode, ia->ia_size);
 776                         lower_ia->ia_size = ia->ia_size;
 777                         lower_ia->ia_valid |= ATTR_SIZE;
 778                         goto out;
 779                 }
 780                 if (num_zeros) {
 781                         char *zeros_virt;
 782
 783                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 784                         if (!zeros_virt) {
 785                                 rc = -ENOMEM;
 786                                 goto out;
 787                         }
 788                         rc = ecryptfs_write(inode, zeros_virt,
 789                                             ia->ia_size, num_zeros);
 790                         kfree(zeros_virt);
 791                         if (rc) {
 792                                 printk(KERN_ERR "Error attempting to zero out "
 793                                        "the remainder of the end page on "
 794                                        "reducing truncate; rc = [%d]\n", rc);
 795                                 goto out;
 796                         }
 797                 }
 798                 truncate_setsize(inode, ia->ia_size);
 799                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 800                 if (rc) {
 801                         printk(KERN_ERR "Problem with "
 802                                "ecryptfs_write_inode_size_to_metadata; "
 803                                "rc = [%d]\n", rc);
 804                         goto out;
 805                 }
 806                 /* We are reducing the size of the ecryptfs file, and need to
 807                  * know if we need to reduce the size of the lower file. */
 808                 lower_size_before_truncate =
 809                     upper_size_to_lower_size(crypt_stat, i_size);
 810                 lower_size_after_truncate =
 811                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 812                 if (lower_size_after_truncate < lower_size_before_truncate) {
 813                         lower_ia->ia_size = lower_size_after_truncate;
 814                         lower_ia->ia_valid |= ATTR_SIZE;
 815                 } else
 816                         lower_ia->ia_valid &= ~ATTR_SIZE;
 817         }
 818 out:
 819         ecryptfs_put_lower_file(inode);
 820         return rc;
 821 }
 822
 823 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 824 {
 825         struct ecryptfs_crypt_stat *crypt_stat;
 826         loff_t lower_oldsize, lower_newsize;
 827
 828         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 829         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 830                                                  i_size_read(inode));
 831         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 832         if (lower_newsize > lower_oldsize) {
 833                 /*
 834                  * The eCryptfs inode and the new *lower* size are mixed here
 835                  * because we may not have the lower i_mutex held and/or it may
 836                  * not be appropriate to call inode_newsize_ok() with inodes
 837                  * from other filesystems.
 838                  */
 839                 return inode_newsize_ok(inode, lower_newsize);
 840         }
 841
 842         return 0;
 843 }
 844
 845 /**
 846  * ecryptfs_truncate
 847  * @dentry: The ecryptfs layer dentry
 848  * @new_length: The length to expand the file to
 849  *
 850  * Simple function that handles the truncation of an eCryptfs inode and
 851  * its corresponding lower inode.
 852  *
 853  * Returns zero on success; non-zero otherwise
 854  */
 855 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 856 {
 857         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 858         struct iattr lower_ia = { .ia_valid = 0 };
 859         int rc;
 860
 861         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 862         if (rc)
 863                 return rc;
 864
 865         rc = truncate_upper(dentry, &ia, &lower_ia);
 866         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 867                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 868
 869                 mutex_lock(&d_inode(lower_dentry)->i_mutex);
 870                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 871                 mutex_unlock(&d_inode(lower_dentry)->i_mutex);
 872         }
 873         return rc;
 874 }
 875
 876 static int
 877 ecryptfs_permission(struct inode *inode, int mask)
 878 {
 879         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 880 }
 881
 882 /**
 883  * ecryptfs_setattr
 884  * @dentry: dentry handle to the inode to modify
 885  * @ia: Structure with flags of what to change and values
 886  *
 887  * Updates the metadata of an inode. If the update is to the size
 888  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 889  * of both the ecryptfs inode and the lower inode.
 890  *
 891  * All other metadata changes will be passed right to the lower filesystem,
 892  * and we will just update our inode to look like the lower.
 893  */
 894 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 895 {
 896         int rc = 0;
 897         struct dentry *lower_dentry;
 898         struct iattr lower_ia;
 899         struct inode *inode;
 900         struct inode *lower_inode;
 901         struct ecryptfs_crypt_stat *crypt_stat;
 902
 903         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 904         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 905                 ecryptfs_init_crypt_stat(crypt_stat);
 906         inode = d_inode(dentry);
 907         lower_inode = ecryptfs_inode_to_lower(inode);
 908         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 909         mutex_lock(&crypt_stat->cs_mutex);
 910         if (d_is_dir(dentry))
 911                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 912         else if (d_is_reg(dentry)
 913                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 914                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 915                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 916
 917                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 918                         dentry->d_sb)->mount_crypt_stat;
 919                 rc = ecryptfs_get_lower_file(dentry, inode);
 920                 if (rc) {
 921                         mutex_unlock(&crypt_stat->cs_mutex);
 922                         goto out;
 923                 }
 924                 rc = ecryptfs_read_metadata(dentry);
 925                 ecryptfs_put_lower_file(inode);
 926                 if (rc) {
 927                         if (!(mount_crypt_stat->flags
 928                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 929                                 rc = -EIO;
 930                                 printk(KERN_WARNING "Either the lower file "
 931                                        "is not in a valid eCryptfs format, "
 932                                        "or the key could not be retrieved. "
 933                                        "Plaintext passthrough mode is not "
 934                                        "enabled; returning -EIO\n");
 935                                 mutex_unlock(&crypt_stat->cs_mutex);
 936                                 goto out;
 937                         }
 938                         rc = 0;
 939                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 940                                                | ECRYPTFS_ENCRYPTED);
 941                 }
 942         }
 943         mutex_unlock(&crypt_stat->cs_mutex);
 944
 945         rc = inode_change_ok(inode, ia);
 946         if (rc)
 947                 goto out;
 948         if (ia->ia_valid & ATTR_SIZE) {
 949                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 950                 if (rc)
 951                         goto out;
 952         }
 953
 954         memcpy(&lower_ia, ia, sizeof(lower_ia));
 955         if (ia->ia_valid & ATTR_FILE)
 956                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 957         if (ia->ia_valid & ATTR_SIZE) {
 958                 rc = truncate_upper(dentry, ia, &lower_ia);
 959                 if (rc < 0)
 960                         goto out;
 961         }
 962
 963         /*
 964          * mode change is for clearing setuid/setgid bits. Allow lower fs
 965          * to interpret this in its own way.
 966          */
 967         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 968                 lower_ia.ia_valid &= ~ATTR_MODE;
 969
 970         mutex_lock(&d_inode(lower_dentry)->i_mutex);
 971         rc = notify_change(lower_dentry, &lower_ia, NULL);
 972         mutex_unlock(&d_inode(lower_dentry)->i_mutex);
 973 out:
 974         fsstack_copy_attr_all(inode, lower_inode);
 975         return rc;
 976 }
 977
 978 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
 979                                  struct kstat *stat)
 980 {
 981         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 982         int rc = 0;
 983
 984         mount_crypt_stat = &ecryptfs_superblock_to_private(
 985                                                 dentry->d_sb)->mount_crypt_stat;
 986         generic_fillattr(d_inode(dentry), stat);
 987         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 988                 char *target;
 989                 size_t targetsiz;
 990
 991                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 992                 if (!IS_ERR(target)) {
 993                         kfree(target);
 994                         stat->size = targetsiz;
 995                 } else {
 996                         rc = PTR_ERR(target);
 997                 }
 998         }
 999         return rc;
1000 }
1001
1002 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1003                             struct kstat *stat)
1004 {
1005         struct kstat lower_stat;
1006         int rc;
1007
1008         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
1009         if (!rc) {
1010                 fsstack_copy_attr_all(d_inode(dentry),
1011                                       ecryptfs_inode_to_lower(d_inode(dentry)));
1012                 generic_fillattr(d_inode(dentry), stat);
1013                 stat->blocks = lower_stat.blocks;
1014         }
1015         return rc;
1016 }
1017
1018 int
1019 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1020                   size_t size, int flags)
1021 {
1022         int rc = 0;
1023         struct dentry *lower_dentry;
1024
1025         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1026         if (!d_inode(lower_dentry)->i_op->setxattr) {
1027                 rc = -EOPNOTSUPP;
1028                 goto out;
1029         }
1030
1031         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1032         if (!rc && d_really_is_positive(dentry))
1033                 fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry));
1034 out:
1035         return rc;
1036 }
1037
1038 ssize_t
1039 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1040                         void *value, size_t size)
1041 {
1042         int rc = 0;
1043
1044         if (!d_inode(lower_dentry)->i_op->getxattr) {
1045                 rc = -EOPNOTSUPP;
1046                 goto out;
1047         }
1048         mutex_lock(&d_inode(lower_dentry)->i_mutex);
1049         rc = d_inode(lower_dentry)->i_op->getxattr(lower_dentry, name, value,
1050                                                    size);
1051         mutex_unlock(&d_inode(lower_dentry)->i_mutex);
1052 out:
1053         return rc;
1054 }
1055
1056 static ssize_t
1057 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1058                   size_t size)
1059 {
1060         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1061                                        value, size);
1062 }
1063
1064 static ssize_t
1065 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1066 {
1067         int rc = 0;
1068         struct dentry *lower_dentry;
1069
1070         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1071         if (!d_inode(lower_dentry)->i_op->listxattr) {
1072                 rc = -EOPNOTSUPP;
1073                 goto out;
1074         }
1075         mutex_lock(&d_inode(lower_dentry)->i_mutex);
1076         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1077         mutex_unlock(&d_inode(lower_dentry)->i_mutex);
1078 out:
1079         return rc;
1080 }
1081
1082 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1083 {
1084         int rc = 0;
1085         struct dentry *lower_dentry;
1086
1087         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1088         if (!d_inode(lower_dentry)->i_op->removexattr) {
1089                 rc = -EOPNOTSUPP;
1090                 goto out;
1091         }
1092         mutex_lock(&d_inode(lower_dentry)->i_mutex);
1093         rc = d_inode(lower_dentry)->i_op->removexattr(lower_dentry, name);
1094         mutex_unlock(&d_inode(lower_dentry)->i_mutex);
1095 out:
1096         return rc;
1097 }
1098
1099 const struct inode_operations ecryptfs_symlink_iops = {
1100         .readlink = generic_readlink,
1101         .follow_link = ecryptfs_follow_link,
1102         .put_link = kfree_put_link,
1103         .permission = ecryptfs_permission,
1104         .setattr = ecryptfs_setattr,
1105         .getattr = ecryptfs_getattr_link,
1106         .setxattr = ecryptfs_setxattr,
1107         .getxattr = ecryptfs_getxattr,
1108         .listxattr = ecryptfs_listxattr,
1109         .removexattr = ecryptfs_removexattr
1110 };
1111
1112 const struct inode_operations ecryptfs_dir_iops = {
1113         .create = ecryptfs_create,
1114         .lookup = ecryptfs_lookup,
1115         .link = ecryptfs_link,
1116         .unlink = ecryptfs_unlink,
1117         .symlink = ecryptfs_symlink,
1118         .mkdir = ecryptfs_mkdir,
1119         .rmdir = ecryptfs_rmdir,
1120         .mknod = ecryptfs_mknod,
1121         .rename = ecryptfs_rename,
1122         .permission = ecryptfs_permission,
1123         .setattr = ecryptfs_setattr,
1124         .setxattr = ecryptfs_setxattr,
1125         .getxattr = ecryptfs_getxattr,
1126         .listxattr = ecryptfs_listxattr,
1127         .removexattr = ecryptfs_removexattr
1128 };
1129
1130 const struct inode_operations ecryptfs_main_iops = {
1131         .permission = ecryptfs_permission,
1132         .setattr = ecryptfs_setattr,
1133         .getattr = ecryptfs_getattr,
1134         .setxattr = ecryptfs_setxattr,
1135         .getxattr = ecryptfs_getxattr,
1136         .listxattr = ecryptfs_listxattr,
1137         .removexattr = ecryptfs_removexattr
1138 };