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/fs_stack.h>
  33 #include <linux/slab.h>
  34 #include <linux/xattr.h>
  35 #include <asm/unaligned.h>
  36 #include "ecryptfs_kernel.h"
  37
  38 static struct dentry *lock_parent(struct dentry *dentry)
  39 {
  40         struct dentry *dir;
  41
  42         dir = dget_parent(dentry);
  43         inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
  44         return dir;
  45 }
  46
  47 static void unlock_dir(struct dentry *dir)
  48 {
  49         inode_unlock(d_inode(dir));
  50         dput(dir);
  51 }
  52
  53 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
  54 {
  55         return ecryptfs_inode_to_lower(inode) == lower_inode;
  56 }
  57
  58 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
  59 {
  60         struct inode *lower_inode = opaque;
  61
  62         ecryptfs_set_inode_lower(inode, lower_inode);
  63         fsstack_copy_attr_all(inode, lower_inode);
  64         /* i_size will be overwritten for encrypted regular files */
  65         fsstack_copy_inode_size(inode, lower_inode);
  66         inode->i_ino = lower_inode->i_ino;
  67         inode->i_mapping->a_ops = &ecryptfs_aops;
  68
  69         if (S_ISLNK(inode->i_mode))
  70                 inode->i_op = &ecryptfs_symlink_iops;
  71         else if (S_ISDIR(inode->i_mode))
  72                 inode->i_op = &ecryptfs_dir_iops;
  73         else
  74                 inode->i_op = &ecryptfs_main_iops;
  75
  76         if (S_ISDIR(inode->i_mode))
  77                 inode->i_fop = &ecryptfs_dir_fops;
  78         else if (special_file(inode->i_mode))
  79                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
  80         else
  81                 inode->i_fop = &ecryptfs_main_fops;
  82
  83         return 0;
  84 }
  85
  86 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  87                                           struct super_block *sb)
  88 {
  89         struct inode *inode;
  90
  91         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  92                 return ERR_PTR(-EXDEV);
  93         if (!igrab(lower_inode))
  94                 return ERR_PTR(-ESTALE);
  95         inode = iget5_locked(sb, (unsigned long)lower_inode,
  96                              ecryptfs_inode_test, ecryptfs_inode_set,
  97                              lower_inode);
  98         if (!inode) {
  99                 iput(lower_inode);
 100                 return ERR_PTR(-EACCES);
 101         }
 102         if (!(inode->i_state & I_NEW))
 103                 iput(lower_inode);
 104
 105         return inode;
 106 }
 107
 108 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 109                                  struct super_block *sb)
 110 {
 111         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 112
 113         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 114                 unlock_new_inode(inode);
 115
 116         return inode;
 117 }
 118
 119 /**
 120  * ecryptfs_interpose
 121  * @lower_dentry: Existing dentry in the lower filesystem
 122  * @dentry: ecryptfs' dentry
 123  * @sb: ecryptfs's super_block
 124  *
 125  * Interposes upper and lower dentries.
 126  *
 127  * Returns zero on success; non-zero otherwise
 128  */
 129 static int ecryptfs_interpose(struct dentry *lower_dentry,
 130                               struct dentry *dentry, struct super_block *sb)
 131 {
 132         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 133
 134         if (IS_ERR(inode))
 135                 return PTR_ERR(inode);
 136         d_instantiate(dentry, inode);
 137
 138         return 0;
 139 }
 140
 141 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 142                               struct inode *inode)
 143 {
 144         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 145         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 146         struct dentry *lower_dir_dentry;
 147         int rc;
 148
 149         dget(lower_dentry);
 150         lower_dir_dentry = lock_parent(lower_dentry);
 151         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 152         if (rc) {
 153                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 154                 goto out_unlock;
 155         }
 156         fsstack_copy_attr_times(dir, lower_dir_inode);
 157         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 158         inode->i_ctime = dir->i_ctime;
 159         d_drop(dentry);
 160 out_unlock:
 161         unlock_dir(lower_dir_dentry);
 162         dput(lower_dentry);
 163         return rc;
 164 }
 165
 166 /**
 167  * ecryptfs_do_create
 168  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 169  * @ecryptfs_dentry: New file's dentry in ecryptfs
 170  * @mode: The mode of the new file
 171  *
 172  * Creates the underlying file and the eCryptfs inode which will link to
 173  * it. It will also update the eCryptfs directory inode to mimic the
 174  * stat of the lower directory inode.
 175  *
 176  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 177  */
 178 static struct inode *
 179 ecryptfs_do_create(struct inode *directory_inode,
 180                    struct dentry *ecryptfs_dentry, umode_t mode)
 181 {
 182         int rc;
 183         struct dentry *lower_dentry;
 184         struct dentry *lower_dir_dentry;
 185         struct inode *inode;
 186
 187         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 188         lower_dir_dentry = lock_parent(lower_dentry);
 189         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 190         if (rc) {
 191                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 192                        "rc = [%d]\n", __func__, rc);
 193                 inode = ERR_PTR(rc);
 194                 goto out_lock;
 195         }
 196         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 197                                      directory_inode->i_sb);
 198         if (IS_ERR(inode)) {
 199                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 200                 goto out_lock;
 201         }
 202         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 203         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 204 out_lock:
 205         unlock_dir(lower_dir_dentry);
 206         return inode;
 207 }
 208
 209 /**
 210  * ecryptfs_initialize_file
 211  *
 212  * Cause the file to be changed from a basic empty file to an ecryptfs
 213  * file with a header and first data page.
 214  *
 215  * Returns zero on success
 216  */
 217 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 218                              struct inode *ecryptfs_inode)
 219 {
 220         struct ecryptfs_crypt_stat *crypt_stat =
 221                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 222         int rc = 0;
 223
 224         if (S_ISDIR(ecryptfs_inode->i_mode)) {
 225                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 226                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 227                 goto out;
 228         }
 229         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 230         rc = ecryptfs_new_file_context(ecryptfs_inode);
 231         if (rc) {
 232                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 233                                 "context; rc = [%d]\n", rc);
 234                 goto out;
 235         }
 236         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 237         if (rc) {
 238                 printk(KERN_ERR "%s: Error attempting to initialize "
 239                         "the lower file for the dentry with name "
 240                         "[%pd]; rc = [%d]\n", __func__,
 241                         ecryptfs_dentry, rc);
 242                 goto out;
 243         }
 244         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 245         if (rc)
 246                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 247         ecryptfs_put_lower_file(ecryptfs_inode);
 248 out:
 249         return rc;
 250 }
 251
 252 /**
 253  * ecryptfs_create
 254  * @dir: The inode of the directory in which to create the file.
 255  * @dentry: The eCryptfs dentry
 256  * @mode: The mode of the new file.
 257  *
 258  * Creates a new file.
 259  *
 260  * Returns zero on success; non-zero on error condition
 261  */
 262 static int
 263 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 264                 umode_t mode, bool excl)
 265 {
 266         struct inode *ecryptfs_inode;
 267         int rc;
 268
 269         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 270                                             mode);
 271         if (IS_ERR(ecryptfs_inode)) {
 272                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 273                                 "lower filesystem\n");
 274                 rc = PTR_ERR(ecryptfs_inode);
 275                 goto out;
 276         }
 277         /* At this point, a file exists on "disk"; we need to make sure
 278          * that this on disk file is prepared to be an ecryptfs file */
 279         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 280         if (rc) {
 281                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 282                                    ecryptfs_inode);
 283                 iget_failed(ecryptfs_inode);
 284                 goto out;
 285         }
 286         unlock_new_inode(ecryptfs_inode);
 287         d_instantiate(ecryptfs_dentry, ecryptfs_inode);
 288 out:
 289         return rc;
 290 }
 291
 292 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 293 {
 294         struct ecryptfs_crypt_stat *crypt_stat;
 295         int rc;
 296
 297         rc = ecryptfs_get_lower_file(dentry, inode);
 298         if (rc) {
 299                 printk(KERN_ERR "%s: Error attempting to initialize "
 300                         "the lower file for the dentry with name "
 301                         "[%pd]; rc = [%d]\n", __func__,
 302                         dentry, rc);
 303                 return rc;
 304         }
 305
 306         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 307         /* TODO: lock for crypt_stat comparison */
 308         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 309                 ecryptfs_set_default_sizes(crypt_stat);
 310
 311         rc = ecryptfs_read_and_validate_header_region(inode);
 312         ecryptfs_put_lower_file(inode);
 313         if (rc) {
 314                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
 315                 if (!rc)
 316                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 317         }
 318
 319         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
 320         return 0;
 321 }
 322
 323 /**
 324  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 325  */
 326 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
 327                                      struct dentry *lower_dentry)
 328 {
 329         struct inode *inode, *lower_inode = d_inode(lower_dentry);
 330         struct ecryptfs_dentry_info *dentry_info;
 331         struct vfsmount *lower_mnt;
 332         int rc = 0;
 333
 334         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 335         if (!dentry_info) {
 336                 dput(lower_dentry);
 337                 return ERR_PTR(-ENOMEM);
 338         }
 339
 340         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 341         fsstack_copy_attr_atime(d_inode(dentry->d_parent),
 342                                 d_inode(lower_dentry->d_parent));
 343         BUG_ON(!d_count(lower_dentry));
 344
 345         ecryptfs_set_dentry_private(dentry, dentry_info);
 346         dentry_info->lower_path.mnt = lower_mnt;
 347         dentry_info->lower_path.dentry = lower_dentry;
 348
 349         if (d_really_is_negative(lower_dentry)) {
 350                 /* We want to add because we couldn't find in lower */
 351                 d_add(dentry, NULL);
 352                 return NULL;
 353         }
 354         inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
 355         if (IS_ERR(inode)) {
 356                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 357                        __func__, PTR_ERR(inode));
 358                 return ERR_CAST(inode);
 359         }
 360         if (S_ISREG(inode->i_mode)) {
 361                 rc = ecryptfs_i_size_read(dentry, inode);
 362                 if (rc) {
 363                         make_bad_inode(inode);
 364                         return ERR_PTR(rc);
 365                 }
 366         }
 367
 368         if (inode->i_state & I_NEW)
 369                 unlock_new_inode(inode);
 370         return d_splice_alias(inode, dentry);
 371 }
 372
 373 /**
 374  * ecryptfs_lookup
 375  * @ecryptfs_dir_inode: The eCryptfs directory inode
 376  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 377  * @flags: lookup flags
 378  *
 379  * Find a file on disk. If the file does not exist, then we'll add it to the
 380  * dentry cache and continue on to read it from the disk.
 381  */
 382 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 383                                       struct dentry *ecryptfs_dentry,
 384                                       unsigned int flags)
 385 {
 386         char *encrypted_and_encoded_name = NULL;
 387         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 388         struct dentry *lower_dir_dentry, *lower_dentry;
 389         const char *name = ecryptfs_dentry->d_name.name;
 390         size_t len = ecryptfs_dentry->d_name.len;
 391         struct dentry *res;
 392         int rc = 0;
 393
 394         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 395
 396         mount_crypt_stat = &ecryptfs_superblock_to_private(
 397                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 398         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 399                 rc = ecryptfs_encrypt_and_encode_filename(
 400                         &encrypted_and_encoded_name, &len,
 401                         mount_crypt_stat, name, len);
 402                 if (rc) {
 403                         printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 404                                "filename; rc = [%d]\n", __func__, rc);
 405                         return ERR_PTR(rc);
 406                 }
 407                 name = encrypted_and_encoded_name;
 408         }
 409
 410         lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
 411         if (IS_ERR(lower_dentry)) {
 412                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 413                                 "[%ld] on lower_dentry = [%s]\n", __func__,
 414                                 PTR_ERR(lower_dentry),
 415                                 name);
 416                 res = ERR_CAST(lower_dentry);
 417         } else {
 418                 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
 419         }
 420         kfree(encrypted_and_encoded_name);
 421         return res;
 422 }
 423
 424 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 425                          struct dentry *new_dentry)
 426 {
 427         struct dentry *lower_old_dentry;
 428         struct dentry *lower_new_dentry;
 429         struct dentry *lower_dir_dentry;
 430         u64 file_size_save;
 431         int rc;
 432
 433         file_size_save = i_size_read(d_inode(old_dentry));
 434         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 435         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 436         dget(lower_old_dentry);
 437         dget(lower_new_dentry);
 438         lower_dir_dentry = lock_parent(lower_new_dentry);
 439         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 440                       lower_new_dentry, NULL);
 441         if (rc || d_really_is_negative(lower_new_dentry))
 442                 goto out_lock;
 443         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 444         if (rc)
 445                 goto out_lock;
 446         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 447         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 448         set_nlink(d_inode(old_dentry),
 449                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 450         i_size_write(d_inode(new_dentry), file_size_save);
 451 out_lock:
 452         unlock_dir(lower_dir_dentry);
 453         dput(lower_new_dentry);
 454         dput(lower_old_dentry);
 455         return rc;
 456 }
 457
 458 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 459 {
 460         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 461 }
 462
 463 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 464                             const char *symname)
 465 {
 466         int rc;
 467         struct dentry *lower_dentry;
 468         struct dentry *lower_dir_dentry;
 469         char *encoded_symname;
 470         size_t encoded_symlen;
 471         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 472
 473         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 474         dget(lower_dentry);
 475         lower_dir_dentry = lock_parent(lower_dentry);
 476         mount_crypt_stat = &ecryptfs_superblock_to_private(
 477                 dir->i_sb)->mount_crypt_stat;
 478         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 479                                                   &encoded_symlen,
 480                                                   mount_crypt_stat, symname,
 481                                                   strlen(symname));
 482         if (rc)
 483                 goto out_lock;
 484         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 485                          encoded_symname);
 486         kfree(encoded_symname);
 487         if (rc || d_really_is_negative(lower_dentry))
 488                 goto out_lock;
 489         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 490         if (rc)
 491                 goto out_lock;
 492         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 493         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 494 out_lock:
 495         unlock_dir(lower_dir_dentry);
 496         dput(lower_dentry);
 497         if (d_really_is_negative(dentry))
 498                 d_drop(dentry);
 499         return rc;
 500 }
 501
 502 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 503 {
 504         int rc;
 505         struct dentry *lower_dentry;
 506         struct dentry *lower_dir_dentry;
 507
 508         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 509         lower_dir_dentry = lock_parent(lower_dentry);
 510         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 511         if (rc || d_really_is_negative(lower_dentry))
 512                 goto out;
 513         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 514         if (rc)
 515                 goto out;
 516         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 517         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 518         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 519 out:
 520         unlock_dir(lower_dir_dentry);
 521         if (d_really_is_negative(dentry))
 522                 d_drop(dentry);
 523         return rc;
 524 }
 525
 526 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 527 {
 528         struct dentry *lower_dentry;
 529         struct dentry *lower_dir_dentry;
 530         int rc;
 531
 532         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 533         dget(dentry);
 534         lower_dir_dentry = lock_parent(lower_dentry);
 535         dget(lower_dentry);
 536         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 537         dput(lower_dentry);
 538         if (!rc && d_really_is_positive(dentry))
 539                 clear_nlink(d_inode(dentry));
 540         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 541         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 542         unlock_dir(lower_dir_dentry);
 543         if (!rc)
 544                 d_drop(dentry);
 545         dput(dentry);
 546         return rc;
 547 }
 548
 549 static int
 550 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 551 {
 552         int rc;
 553         struct dentry *lower_dentry;
 554         struct dentry *lower_dir_dentry;
 555
 556         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 557         lower_dir_dentry = lock_parent(lower_dentry);
 558         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 559         if (rc || d_really_is_negative(lower_dentry))
 560                 goto out;
 561         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 562         if (rc)
 563                 goto out;
 564         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 565         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 566 out:
 567         unlock_dir(lower_dir_dentry);
 568         if (d_really_is_negative(dentry))
 569                 d_drop(dentry);
 570         return rc;
 571 }
 572
 573 static int
 574 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 575                 struct inode *new_dir, struct dentry *new_dentry,
 576                 unsigned int flags)
 577 {
 578         int rc;
 579         struct dentry *lower_old_dentry;
 580         struct dentry *lower_new_dentry;
 581         struct dentry *lower_old_dir_dentry;
 582         struct dentry *lower_new_dir_dentry;
 583         struct dentry *trap = NULL;
 584         struct inode *target_inode;
 585
 586         if (flags)
 587                 return -EINVAL;
 588
 589         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 590         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 591         dget(lower_old_dentry);
 592         dget(lower_new_dentry);
 593         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 594         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 595         target_inode = d_inode(new_dentry);
 596         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 597         /* source should not be ancestor of target */
 598         if (trap == lower_old_dentry) {
 599                 rc = -EINVAL;
 600                 goto out_lock;
 601         }
 602         /* target should not be ancestor of source */
 603         if (trap == lower_new_dentry) {
 604                 rc = -ENOTEMPTY;
 605                 goto out_lock;
 606         }
 607         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 608                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 609                         NULL, 0);
 610         if (rc)
 611                 goto out_lock;
 612         if (target_inode)
 613                 fsstack_copy_attr_all(target_inode,
 614                                       ecryptfs_inode_to_lower(target_inode));
 615         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 616         if (new_dir != old_dir)
 617                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 618 out_lock:
 619         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 620         dput(lower_new_dir_dentry);
 621         dput(lower_old_dir_dentry);
 622         dput(lower_new_dentry);
 623         dput(lower_old_dentry);
 624         return rc;
 625 }
 626
 627 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 628 {
 629         DEFINE_DELAYED_CALL(done);
 630         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 631         const char *link;
 632         char *buf;
 633         int rc;
 634
 635         link = vfs_get_link(lower_dentry, &done);
 636         if (IS_ERR(link))
 637                 return ERR_CAST(link);
 638
 639         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 640                                                   link, strlen(link));
 641         do_delayed_call(&done);
 642         if (rc)
 643                 return ERR_PTR(rc);
 644
 645         return buf;
 646 }
 647
 648 static const char *ecryptfs_get_link(struct dentry *dentry,
 649                                      struct inode *inode,
 650                                      struct delayed_call *done)
 651 {
 652         size_t len;
 653         char *buf;
 654
 655         if (!dentry)
 656                 return ERR_PTR(-ECHILD);
 657
 658         buf = ecryptfs_readlink_lower(dentry, &len);
 659         if (IS_ERR(buf))
 660                 return buf;
 661         fsstack_copy_attr_atime(d_inode(dentry),
 662                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 663         buf[len] = '\0';
 664         set_delayed_call(done, kfree_link, buf);
 665         return buf;
 666 }
 667
 668 /**
 669  * upper_size_to_lower_size
 670  * @crypt_stat: Crypt_stat associated with file
 671  * @upper_size: Size of the upper file
 672  *
 673  * Calculate the required size of the lower file based on the
 674  * specified size of the upper file. This calculation is based on the
 675  * number of headers in the underlying file and the extent size.
 676  *
 677  * Returns Calculated size of the lower file.
 678  */
 679 static loff_t
 680 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 681                          loff_t upper_size)
 682 {
 683         loff_t lower_size;
 684
 685         lower_size = ecryptfs_lower_header_size(crypt_stat);
 686         if (upper_size != 0) {
 687                 loff_t num_extents;
 688
 689                 num_extents = upper_size >> crypt_stat->extent_shift;
 690                 if (upper_size & ~crypt_stat->extent_mask)
 691                         num_extents++;
 692                 lower_size += (num_extents * crypt_stat->extent_size);
 693         }
 694         return lower_size;
 695 }
 696
 697 /**
 698  * truncate_upper
 699  * @dentry: The ecryptfs layer dentry
 700  * @ia: Address of the ecryptfs inode's attributes
 701  * @lower_ia: Address of the lower inode's attributes
 702  *
 703  * Function to handle truncations modifying the size of the file. Note
 704  * that the file sizes are interpolated. When expanding, we are simply
 705  * writing strings of 0's out. When truncating, we truncate the upper
 706  * inode and update the lower_ia according to the page index
 707  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 708  * the caller must use lower_ia in a call to notify_change() to perform
 709  * the truncation of the lower inode.
 710  *
 711  * Returns zero on success; non-zero otherwise
 712  */
 713 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 714                           struct iattr *lower_ia)
 715 {
 716         int rc = 0;
 717         struct inode *inode = d_inode(dentry);
 718         struct ecryptfs_crypt_stat *crypt_stat;
 719         loff_t i_size = i_size_read(inode);
 720         loff_t lower_size_before_truncate;
 721         loff_t lower_size_after_truncate;
 722
 723         if (unlikely((ia->ia_size == i_size))) {
 724                 lower_ia->ia_valid &= ~ATTR_SIZE;
 725                 return 0;
 726         }
 727         rc = ecryptfs_get_lower_file(dentry, inode);
 728         if (rc)
 729                 return rc;
 730         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 731         /* Switch on growing or shrinking file */
 732         if (ia->ia_size > i_size) {
 733                 char zero[] = { 0x00 };
 734
 735                 lower_ia->ia_valid &= ~ATTR_SIZE;
 736                 /* Write a single 0 at the last position of the file;
 737                  * this triggers code that will fill in 0's throughout
 738                  * the intermediate portion of the previous end of the
 739                  * file and the new and of the file */
 740                 rc = ecryptfs_write(inode, zero,
 741                                     (ia->ia_size - 1), 1);
 742         } else { /* ia->ia_size < i_size_read(inode) */
 743                 /* We're chopping off all the pages down to the page
 744                  * in which ia->ia_size is located. Fill in the end of
 745                  * that page from (ia->ia_size & ~PAGE_MASK) to
 746                  * PAGE_SIZE with zeros. */
 747                 size_t num_zeros = (PAGE_SIZE
 748                                     - (ia->ia_size & ~PAGE_MASK));
 749
 750                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 751                         truncate_setsize(inode, ia->ia_size);
 752                         lower_ia->ia_size = ia->ia_size;
 753                         lower_ia->ia_valid |= ATTR_SIZE;
 754                         goto out;
 755                 }
 756                 if (num_zeros) {
 757                         char *zeros_virt;
 758
 759                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 760                         if (!zeros_virt) {
 761                                 rc = -ENOMEM;
 762                                 goto out;
 763                         }
 764                         rc = ecryptfs_write(inode, zeros_virt,
 765                                             ia->ia_size, num_zeros);
 766                         kfree(zeros_virt);
 767                         if (rc) {
 768                                 printk(KERN_ERR "Error attempting to zero out "
 769                                        "the remainder of the end page on "
 770                                        "reducing truncate; rc = [%d]\n", rc);
 771                                 goto out;
 772                         }
 773                 }
 774                 truncate_setsize(inode, ia->ia_size);
 775                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 776                 if (rc) {
 777                         printk(KERN_ERR "Problem with "
 778                                "ecryptfs_write_inode_size_to_metadata; "
 779                                "rc = [%d]\n", rc);
 780                         goto out;
 781                 }
 782                 /* We are reducing the size of the ecryptfs file, and need to
 783                  * know if we need to reduce the size of the lower file. */
 784                 lower_size_before_truncate =
 785                     upper_size_to_lower_size(crypt_stat, i_size);
 786                 lower_size_after_truncate =
 787                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 788                 if (lower_size_after_truncate < lower_size_before_truncate) {
 789                         lower_ia->ia_size = lower_size_after_truncate;
 790                         lower_ia->ia_valid |= ATTR_SIZE;
 791                 } else
 792                         lower_ia->ia_valid &= ~ATTR_SIZE;
 793         }
 794 out:
 795         ecryptfs_put_lower_file(inode);
 796         return rc;
 797 }
 798
 799 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 800 {
 801         struct ecryptfs_crypt_stat *crypt_stat;
 802         loff_t lower_oldsize, lower_newsize;
 803
 804         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 805         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 806                                                  i_size_read(inode));
 807         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 808         if (lower_newsize > lower_oldsize) {
 809                 /*
 810                  * The eCryptfs inode and the new *lower* size are mixed here
 811                  * because we may not have the lower i_mutex held and/or it may
 812                  * not be appropriate to call inode_newsize_ok() with inodes
 813                  * from other filesystems.
 814                  */
 815                 return inode_newsize_ok(inode, lower_newsize);
 816         }
 817
 818         return 0;
 819 }
 820
 821 /**
 822  * ecryptfs_truncate
 823  * @dentry: The ecryptfs layer dentry
 824  * @new_length: The length to expand the file to
 825  *
 826  * Simple function that handles the truncation of an eCryptfs inode and
 827  * its corresponding lower inode.
 828  *
 829  * Returns zero on success; non-zero otherwise
 830  */
 831 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 832 {
 833         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 834         struct iattr lower_ia = { .ia_valid = 0 };
 835         int rc;
 836
 837         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 838         if (rc)
 839                 return rc;
 840
 841         rc = truncate_upper(dentry, &ia, &lower_ia);
 842         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 843                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 844
 845                 inode_lock(d_inode(lower_dentry));
 846                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 847                 inode_unlock(d_inode(lower_dentry));
 848         }
 849         return rc;
 850 }
 851
 852 static int
 853 ecryptfs_permission(struct inode *inode, int mask)
 854 {
 855         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 856 }
 857
 858 /**
 859  * ecryptfs_setattr
 860  * @dentry: dentry handle to the inode to modify
 861  * @ia: Structure with flags of what to change and values
 862  *
 863  * Updates the metadata of an inode. If the update is to the size
 864  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 865  * of both the ecryptfs inode and the lower inode.
 866  *
 867  * All other metadata changes will be passed right to the lower filesystem,
 868  * and we will just update our inode to look like the lower.
 869  */
 870 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 871 {
 872         int rc = 0;
 873         struct dentry *lower_dentry;
 874         struct iattr lower_ia;
 875         struct inode *inode;
 876         struct inode *lower_inode;
 877         struct ecryptfs_crypt_stat *crypt_stat;
 878
 879         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 880         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
 881                 rc = ecryptfs_init_crypt_stat(crypt_stat);
 882                 if (rc)
 883                         return rc;
 884         }
 885         inode = d_inode(dentry);
 886         lower_inode = ecryptfs_inode_to_lower(inode);
 887         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 888         mutex_lock(&crypt_stat->cs_mutex);
 889         if (d_is_dir(dentry))
 890                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 891         else if (d_is_reg(dentry)
 892                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 893                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 894                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 895
 896                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 897                         dentry->d_sb)->mount_crypt_stat;
 898                 rc = ecryptfs_get_lower_file(dentry, inode);
 899                 if (rc) {
 900                         mutex_unlock(&crypt_stat->cs_mutex);
 901                         goto out;
 902                 }
 903                 rc = ecryptfs_read_metadata(dentry);
 904                 ecryptfs_put_lower_file(inode);
 905                 if (rc) {
 906                         if (!(mount_crypt_stat->flags
 907                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 908                                 rc = -EIO;
 909                                 printk(KERN_WARNING "Either the lower file "
 910                                        "is not in a valid eCryptfs format, "
 911                                        "or the key could not be retrieved. "
 912                                        "Plaintext passthrough mode is not "
 913                                        "enabled; returning -EIO\n");
 914                                 mutex_unlock(&crypt_stat->cs_mutex);
 915                                 goto out;
 916                         }
 917                         rc = 0;
 918                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 919                                                | ECRYPTFS_ENCRYPTED);
 920                 }
 921         }
 922         mutex_unlock(&crypt_stat->cs_mutex);
 923
 924         rc = setattr_prepare(dentry, ia);
 925         if (rc)
 926                 goto out;
 927         if (ia->ia_valid & ATTR_SIZE) {
 928                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 929                 if (rc)
 930                         goto out;
 931         }
 932
 933         memcpy(&lower_ia, ia, sizeof(lower_ia));
 934         if (ia->ia_valid & ATTR_FILE)
 935                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 936         if (ia->ia_valid & ATTR_SIZE) {
 937                 rc = truncate_upper(dentry, ia, &lower_ia);
 938                 if (rc < 0)
 939                         goto out;
 940         }
 941
 942         /*
 943          * mode change is for clearing setuid/setgid bits. Allow lower fs
 944          * to interpret this in its own way.
 945          */
 946         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 947                 lower_ia.ia_valid &= ~ATTR_MODE;
 948
 949         inode_lock(d_inode(lower_dentry));
 950         rc = notify_change(lower_dentry, &lower_ia, NULL);
 951         inode_unlock(d_inode(lower_dentry));
 952 out:
 953         fsstack_copy_attr_all(inode, lower_inode);
 954         return rc;
 955 }
 956
 957 static int ecryptfs_getattr_link(const struct path *path, struct kstat *stat,
 958                                  u32 request_mask, unsigned int flags)
 959 {
 960         struct dentry *dentry = path->dentry;
 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(d_inode(dentry), stat);
 967         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 968                 char *target;
 969                 size_t targetsiz;
 970
 971                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 972                 if (!IS_ERR(target)) {
 973                         kfree(target);
 974                         stat->size = targetsiz;
 975                 } else {
 976                         rc = PTR_ERR(target);
 977                 }
 978         }
 979         return rc;
 980 }
 981
 982 static int ecryptfs_getattr(const struct path *path, struct kstat *stat,
 983                             u32 request_mask, unsigned int flags)
 984 {
 985         struct dentry *dentry = path->dentry;
 986         struct kstat lower_stat;
 987         int rc;
 988
 989         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
 990                          request_mask, flags);
 991         if (!rc) {
 992                 fsstack_copy_attr_all(d_inode(dentry),
 993                                       ecryptfs_inode_to_lower(d_inode(dentry)));
 994                 generic_fillattr(d_inode(dentry), stat);
 995                 stat->blocks = lower_stat.blocks;
 996         }
 997         return rc;
 998 }
 999
1000 int
1001 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1002                   const char *name, const void *value,
1003                   size_t size, int flags)
1004 {
1005         int rc;
1006         struct dentry *lower_dentry;
1007
1008         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1009         if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1010                 rc = -EOPNOTSUPP;
1011                 goto out;
1012         }
1013         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1014         if (!rc && inode)
1015                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1016 out:
1017         return rc;
1018 }
1019
1020 ssize_t
1021 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1022                         const char *name, void *value, size_t size)
1023 {
1024         int rc;
1025
1026         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1027                 rc = -EOPNOTSUPP;
1028                 goto out;
1029         }
1030         inode_lock(lower_inode);
1031         rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1032         inode_unlock(lower_inode);
1033 out:
1034         return rc;
1035 }
1036
1037 static ssize_t
1038 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1039                   const char *name, void *value, size_t size)
1040 {
1041         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1042                                        ecryptfs_inode_to_lower(inode),
1043                                        name, value, size);
1044 }
1045
1046 static ssize_t
1047 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1048 {
1049         int rc = 0;
1050         struct dentry *lower_dentry;
1051
1052         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1053         if (!d_inode(lower_dentry)->i_op->listxattr) {
1054                 rc = -EOPNOTSUPP;
1055                 goto out;
1056         }
1057         inode_lock(d_inode(lower_dentry));
1058         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1059         inode_unlock(d_inode(lower_dentry));
1060 out:
1061         return rc;
1062 }
1063
1064 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1065                                 const char *name)
1066 {
1067         int rc;
1068         struct dentry *lower_dentry;
1069         struct inode *lower_inode;
1070
1071         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1072         lower_inode = ecryptfs_inode_to_lower(inode);
1073         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1074                 rc = -EOPNOTSUPP;
1075                 goto out;
1076         }
1077         inode_lock(lower_inode);
1078         rc = __vfs_removexattr(lower_dentry, name);
1079         inode_unlock(lower_inode);
1080 out:
1081         return rc;
1082 }
1083
1084 const struct inode_operations ecryptfs_symlink_iops = {
1085         .get_link = ecryptfs_get_link,
1086         .permission = ecryptfs_permission,
1087         .setattr = ecryptfs_setattr,
1088         .getattr = ecryptfs_getattr_link,
1089         .listxattr = ecryptfs_listxattr,
1090 };
1091
1092 const struct inode_operations ecryptfs_dir_iops = {
1093         .create = ecryptfs_create,
1094         .lookup = ecryptfs_lookup,
1095         .link = ecryptfs_link,
1096         .unlink = ecryptfs_unlink,
1097         .symlink = ecryptfs_symlink,
1098         .mkdir = ecryptfs_mkdir,
1099         .rmdir = ecryptfs_rmdir,
1100         .mknod = ecryptfs_mknod,
1101         .rename = ecryptfs_rename,
1102         .permission = ecryptfs_permission,
1103         .setattr = ecryptfs_setattr,
1104         .listxattr = ecryptfs_listxattr,
1105 };
1106
1107 const struct inode_operations ecryptfs_main_iops = {
1108         .permission = ecryptfs_permission,
1109         .setattr = ecryptfs_setattr,
1110         .getattr = ecryptfs_getattr,
1111         .listxattr = ecryptfs_listxattr,
1112 };
1113
1114 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1115                               struct dentry *dentry, struct inode *inode,
1116                               const char *name, void *buffer, size_t size)
1117 {
1118         return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1119 }
1120
1121 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1122                               struct dentry *dentry, struct inode *inode,
1123                               const char *name, const void *value, size_t size,
1124                               int flags)
1125 {
1126         if (value)
1127                 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1128         else {
1129                 BUG_ON(flags != XATTR_REPLACE);
1130                 return ecryptfs_removexattr(dentry, inode, name);
1131         }
1132 }
1133
1134 const struct xattr_handler ecryptfs_xattr_handler = {
1135         .prefix = "",  /* match anything */
1136         .get = ecryptfs_xattr_get,
1137         .set = ecryptfs_xattr_set,
1138 };
1139
1140 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1141         &ecryptfs_xattr_handler,
1142         NULL
1143 };