fs/ecryptfs/inode.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2004 Erez Zadok
   5  * Copyright (C) 2001-2004 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #include <linux/file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/dcache.h>
  30 #include <linux/namei.h>
  31 #include <linux/mount.h>
  32 #include <linux/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         d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
 287 out:
 288         return rc;
 289 }
 290
 291 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 292 {
 293         struct ecryptfs_crypt_stat *crypt_stat;
 294         int rc;
 295
 296         rc = ecryptfs_get_lower_file(dentry, inode);
 297         if (rc) {
 298                 printk(KERN_ERR "%s: Error attempting to initialize "
 299                         "the lower file for the dentry with name "
 300                         "[%pd]; rc = [%d]\n", __func__,
 301                         dentry, rc);
 302                 return rc;
 303         }
 304
 305         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 306         /* TODO: lock for crypt_stat comparison */
 307         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 308                 ecryptfs_set_default_sizes(crypt_stat);
 309
 310         rc = ecryptfs_read_and_validate_header_region(inode);
 311         ecryptfs_put_lower_file(inode);
 312         if (rc) {
 313                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
 314                 if (!rc)
 315                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 316         }
 317
 318         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
 319         return 0;
 320 }
 321
 322 /**
 323  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 324  */
 325 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
 326                                      struct dentry *lower_dentry)
 327 {
 328         struct inode *inode, *lower_inode = d_inode(lower_dentry);
 329         struct ecryptfs_dentry_info *dentry_info;
 330         struct vfsmount *lower_mnt;
 331         int rc = 0;
 332
 333         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 334         if (!dentry_info) {
 335                 dput(lower_dentry);
 336                 return ERR_PTR(-ENOMEM);
 337         }
 338
 339         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 340         fsstack_copy_attr_atime(d_inode(dentry->d_parent),
 341                                 d_inode(lower_dentry->d_parent));
 342         BUG_ON(!d_count(lower_dentry));
 343
 344         ecryptfs_set_dentry_private(dentry, dentry_info);
 345         dentry_info->lower_path.mnt = lower_mnt;
 346         dentry_info->lower_path.dentry = lower_dentry;
 347
 348         if (d_really_is_negative(lower_dentry)) {
 349                 /* We want to add because we couldn't find in lower */
 350                 d_add(dentry, NULL);
 351                 return NULL;
 352         }
 353         inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
 354         if (IS_ERR(inode)) {
 355                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 356                        __func__, PTR_ERR(inode));
 357                 return ERR_CAST(inode);
 358         }
 359         if (S_ISREG(inode->i_mode)) {
 360                 rc = ecryptfs_i_size_read(dentry, inode);
 361                 if (rc) {
 362                         make_bad_inode(inode);
 363                         return ERR_PTR(rc);
 364                 }
 365         }
 366
 367         if (inode->i_state & I_NEW)
 368                 unlock_new_inode(inode);
 369         return d_splice_alias(inode, dentry);
 370 }
 371
 372 /**
 373  * ecryptfs_lookup
 374  * @ecryptfs_dir_inode: The eCryptfs directory inode
 375  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 376  * @flags: lookup flags
 377  *
 378  * Find a file on disk. If the file does not exist, then we'll add it to the
 379  * dentry cache and continue on to read it from the disk.
 380  */
 381 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 382                                       struct dentry *ecryptfs_dentry,
 383                                       unsigned int flags)
 384 {
 385         char *encrypted_and_encoded_name = NULL;
 386         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 387         struct dentry *lower_dir_dentry, *lower_dentry;
 388         const char *name = ecryptfs_dentry->d_name.name;
 389         size_t len = ecryptfs_dentry->d_name.len;
 390         struct dentry *res;
 391         int rc = 0;
 392
 393         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 394
 395         mount_crypt_stat = &ecryptfs_superblock_to_private(
 396                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 397         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 398                 rc = ecryptfs_encrypt_and_encode_filename(
 399                         &encrypted_and_encoded_name, &len,
 400                         mount_crypt_stat, name, len);
 401                 if (rc) {
 402                         printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 403                                "filename; rc = [%d]\n", __func__, rc);
 404                         return ERR_PTR(rc);
 405                 }
 406                 name = encrypted_and_encoded_name;
 407         }
 408
 409         lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
 410         if (IS_ERR(lower_dentry)) {
 411                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 412                                 "[%ld] on lower_dentry = [%s]\n", __func__,
 413                                 PTR_ERR(lower_dentry),
 414                                 name);
 415                 res = ERR_CAST(lower_dentry);
 416         } else {
 417                 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
 418         }
 419         kfree(encrypted_and_encoded_name);
 420         return res;
 421 }
 422
 423 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 424                          struct dentry *new_dentry)
 425 {
 426         struct dentry *lower_old_dentry;
 427         struct dentry *lower_new_dentry;
 428         struct dentry *lower_dir_dentry;
 429         u64 file_size_save;
 430         int rc;
 431
 432         file_size_save = i_size_read(d_inode(old_dentry));
 433         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 434         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 435         dget(lower_old_dentry);
 436         dget(lower_new_dentry);
 437         lower_dir_dentry = lock_parent(lower_new_dentry);
 438         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 439                       lower_new_dentry, NULL);
 440         if (rc || d_really_is_negative(lower_new_dentry))
 441                 goto out_lock;
 442         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 443         if (rc)
 444                 goto out_lock;
 445         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 446         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 447         set_nlink(d_inode(old_dentry),
 448                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 449         i_size_write(d_inode(new_dentry), file_size_save);
 450 out_lock:
 451         unlock_dir(lower_dir_dentry);
 452         dput(lower_new_dentry);
 453         dput(lower_old_dentry);
 454         return rc;
 455 }
 456
 457 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 458 {
 459         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 460 }
 461
 462 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 463                             const char *symname)
 464 {
 465         int rc;
 466         struct dentry *lower_dentry;
 467         struct dentry *lower_dir_dentry;
 468         char *encoded_symname;
 469         size_t encoded_symlen;
 470         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 471
 472         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 473         dget(lower_dentry);
 474         lower_dir_dentry = lock_parent(lower_dentry);
 475         mount_crypt_stat = &ecryptfs_superblock_to_private(
 476                 dir->i_sb)->mount_crypt_stat;
 477         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 478                                                   &encoded_symlen,
 479                                                   mount_crypt_stat, symname,
 480                                                   strlen(symname));
 481         if (rc)
 482                 goto out_lock;
 483         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 484                          encoded_symname);
 485         kfree(encoded_symname);
 486         if (rc || d_really_is_negative(lower_dentry))
 487                 goto out_lock;
 488         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 489         if (rc)
 490                 goto out_lock;
 491         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 492         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 493 out_lock:
 494         unlock_dir(lower_dir_dentry);
 495         dput(lower_dentry);
 496         if (d_really_is_negative(dentry))
 497                 d_drop(dentry);
 498         return rc;
 499 }
 500
 501 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 502 {
 503         int rc;
 504         struct dentry *lower_dentry;
 505         struct dentry *lower_dir_dentry;
 506
 507         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 508         lower_dir_dentry = lock_parent(lower_dentry);
 509         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 510         if (rc || d_really_is_negative(lower_dentry))
 511                 goto out;
 512         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 513         if (rc)
 514                 goto out;
 515         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 516         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 517         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 518 out:
 519         unlock_dir(lower_dir_dentry);
 520         if (d_really_is_negative(dentry))
 521                 d_drop(dentry);
 522         return rc;
 523 }
 524
 525 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 526 {
 527         struct dentry *lower_dentry;
 528         struct dentry *lower_dir_dentry;
 529         int rc;
 530
 531         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 532         dget(dentry);
 533         lower_dir_dentry = lock_parent(lower_dentry);
 534         dget(lower_dentry);
 535         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 536         dput(lower_dentry);
 537         if (!rc && d_really_is_positive(dentry))
 538                 clear_nlink(d_inode(dentry));
 539         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 540         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 541         unlock_dir(lower_dir_dentry);
 542         if (!rc)
 543                 d_drop(dentry);
 544         dput(dentry);
 545         return rc;
 546 }
 547
 548 static int
 549 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 550 {
 551         int rc;
 552         struct dentry *lower_dentry;
 553         struct dentry *lower_dir_dentry;
 554
 555         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 556         lower_dir_dentry = lock_parent(lower_dentry);
 557         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 558         if (rc || d_really_is_negative(lower_dentry))
 559                 goto out;
 560         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 561         if (rc)
 562                 goto out;
 563         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 564         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 565 out:
 566         unlock_dir(lower_dir_dentry);
 567         if (d_really_is_negative(dentry))
 568                 d_drop(dentry);
 569         return rc;
 570 }
 571
 572 static int
 573 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 574                 struct inode *new_dir, struct dentry *new_dentry,
 575                 unsigned int flags)
 576 {
 577         int rc;
 578         struct dentry *lower_old_dentry;
 579         struct dentry *lower_new_dentry;
 580         struct dentry *lower_old_dir_dentry;
 581         struct dentry *lower_new_dir_dentry;
 582         struct dentry *trap = NULL;
 583         struct inode *target_inode;
 584
 585         if (flags)
 586                 return -EINVAL;
 587
 588         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 589         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 590         dget(lower_old_dentry);
 591         dget(lower_new_dentry);
 592         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 593         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 594         target_inode = d_inode(new_dentry);
 595         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 596         /* source should not be ancestor of target */
 597         if (trap == lower_old_dentry) {
 598                 rc = -EINVAL;
 599                 goto out_lock;
 600         }
 601         /* target should not be ancestor of source */
 602         if (trap == lower_new_dentry) {
 603                 rc = -ENOTEMPTY;
 604                 goto out_lock;
 605         }
 606         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 607                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 608                         NULL, 0);
 609         if (rc)
 610                 goto out_lock;
 611         if (target_inode)
 612                 fsstack_copy_attr_all(target_inode,
 613                                       ecryptfs_inode_to_lower(target_inode));
 614         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 615         if (new_dir != old_dir)
 616                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 617 out_lock:
 618         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 619         dput(lower_new_dir_dentry);
 620         dput(lower_old_dir_dentry);
 621         dput(lower_new_dentry);
 622         dput(lower_old_dentry);
 623         return rc;
 624 }
 625
 626 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 627 {
 628         DEFINE_DELAYED_CALL(done);
 629         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 630         const char *link;
 631         char *buf;
 632         int rc;
 633
 634         link = vfs_get_link(lower_dentry, &done);
 635         if (IS_ERR(link))
 636                 return ERR_CAST(link);
 637
 638         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 639                                                   link, strlen(link));
 640         do_delayed_call(&done);
 641         if (rc)
 642                 return ERR_PTR(rc);
 643
 644         return buf;
 645 }
 646
 647 static const char *ecryptfs_get_link(struct dentry *dentry,
 648                                      struct inode *inode,
 649                                      struct delayed_call *done)
 650 {
 651         size_t len;
 652         char *buf;
 653
 654         if (!dentry)
 655                 return ERR_PTR(-ECHILD);
 656
 657         buf = ecryptfs_readlink_lower(dentry, &len);
 658         if (IS_ERR(buf))
 659                 return buf;
 660         fsstack_copy_attr_atime(d_inode(dentry),
 661                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 662         buf[len] = '\0';
 663         set_delayed_call(done, kfree_link, buf);
 664         return buf;
 665 }
 666
 667 /**
 668  * upper_size_to_lower_size
 669  * @crypt_stat: Crypt_stat associated with file
 670  * @upper_size: Size of the upper file
 671  *
 672  * Calculate the required size of the lower file based on the
 673  * specified size of the upper file. This calculation is based on the
 674  * number of headers in the underlying file and the extent size.
 675  *
 676  * Returns Calculated size of the lower file.
 677  */
 678 static loff_t
 679 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 680                          loff_t upper_size)
 681 {
 682         loff_t lower_size;
 683
 684         lower_size = ecryptfs_lower_header_size(crypt_stat);
 685         if (upper_size != 0) {
 686                 loff_t num_extents;
 687
 688                 num_extents = upper_size >> crypt_stat->extent_shift;
 689                 if (upper_size & ~crypt_stat->extent_mask)
 690                         num_extents++;
 691                 lower_size += (num_extents * crypt_stat->extent_size);
 692         }
 693         return lower_size;
 694 }
 695
 696 /**
 697  * truncate_upper
 698  * @dentry: The ecryptfs layer dentry
 699  * @ia: Address of the ecryptfs inode's attributes
 700  * @lower_ia: Address of the lower inode's attributes
 701  *
 702  * Function to handle truncations modifying the size of the file. Note
 703  * that the file sizes are interpolated. When expanding, we are simply
 704  * writing strings of 0's out. When truncating, we truncate the upper
 705  * inode and update the lower_ia according to the page index
 706  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 707  * the caller must use lower_ia in a call to notify_change() to perform
 708  * the truncation of the lower inode.
 709  *
 710  * Returns zero on success; non-zero otherwise
 711  */
 712 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 713                           struct iattr *lower_ia)
 714 {
 715         int rc = 0;
 716         struct inode *inode = d_inode(dentry);
 717         struct ecryptfs_crypt_stat *crypt_stat;
 718         loff_t i_size = i_size_read(inode);
 719         loff_t lower_size_before_truncate;
 720         loff_t lower_size_after_truncate;
 721
 722         if (unlikely((ia->ia_size == i_size))) {
 723                 lower_ia->ia_valid &= ~ATTR_SIZE;
 724                 return 0;
 725         }
 726         rc = ecryptfs_get_lower_file(dentry, inode);
 727         if (rc)
 728                 return rc;
 729         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 730         /* Switch on growing or shrinking file */
 731         if (ia->ia_size > i_size) {
 732                 char zero[] = { 0x00 };
 733
 734                 lower_ia->ia_valid &= ~ATTR_SIZE;
 735                 /* Write a single 0 at the last position of the file;
 736                  * this triggers code that will fill in 0's throughout
 737                  * the intermediate portion of the previous end of the
 738                  * file and the new and of the file */
 739                 rc = ecryptfs_write(inode, zero,
 740                                     (ia->ia_size - 1), 1);
 741         } else { /* ia->ia_size < i_size_read(inode) */
 742                 /* We're chopping off all the pages down to the page
 743                  * in which ia->ia_size is located. Fill in the end of
 744                  * that page from (ia->ia_size & ~PAGE_MASK) to
 745                  * PAGE_SIZE with zeros. */
 746                 size_t num_zeros = (PAGE_SIZE
 747                                     - (ia->ia_size & ~PAGE_MASK));
 748
 749                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 750                         truncate_setsize(inode, ia->ia_size);
 751                         lower_ia->ia_size = ia->ia_size;
 752                         lower_ia->ia_valid |= ATTR_SIZE;
 753                         goto out;
 754                 }
 755                 if (num_zeros) {
 756                         char *zeros_virt;
 757
 758                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 759                         if (!zeros_virt) {
 760                                 rc = -ENOMEM;
 761                                 goto out;
 762                         }
 763                         rc = ecryptfs_write(inode, zeros_virt,
 764                                             ia->ia_size, num_zeros);
 765                         kfree(zeros_virt);
 766                         if (rc) {
 767                                 printk(KERN_ERR "Error attempting to zero out "
 768                                        "the remainder of the end page on "
 769                                        "reducing truncate; rc = [%d]\n", rc);
 770                                 goto out;
 771                         }
 772                 }
 773                 truncate_setsize(inode, ia->ia_size);
 774                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 775                 if (rc) {
 776                         printk(KERN_ERR "Problem with "
 777                                "ecryptfs_write_inode_size_to_metadata; "
 778                                "rc = [%d]\n", rc);
 779                         goto out;
 780                 }
 781                 /* We are reducing the size of the ecryptfs file, and need to
 782                  * know if we need to reduce the size of the lower file. */
 783                 lower_size_before_truncate =
 784                     upper_size_to_lower_size(crypt_stat, i_size);
 785                 lower_size_after_truncate =
 786                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 787                 if (lower_size_after_truncate < lower_size_before_truncate) {
 788                         lower_ia->ia_size = lower_size_after_truncate;
 789                         lower_ia->ia_valid |= ATTR_SIZE;
 790                 } else
 791                         lower_ia->ia_valid &= ~ATTR_SIZE;
 792         }
 793 out:
 794         ecryptfs_put_lower_file(inode);
 795         return rc;
 796 }
 797
 798 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 799 {
 800         struct ecryptfs_crypt_stat *crypt_stat;
 801         loff_t lower_oldsize, lower_newsize;
 802
 803         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 804         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 805                                                  i_size_read(inode));
 806         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 807         if (lower_newsize > lower_oldsize) {
 808                 /*
 809                  * The eCryptfs inode and the new *lower* size are mixed here
 810                  * because we may not have the lower i_mutex held and/or it may
 811                  * not be appropriate to call inode_newsize_ok() with inodes
 812                  * from other filesystems.
 813                  */
 814                 return inode_newsize_ok(inode, lower_newsize);
 815         }
 816
 817         return 0;
 818 }
 819
 820 /**
 821  * ecryptfs_truncate
 822  * @dentry: The ecryptfs layer dentry
 823  * @new_length: The length to expand the file to
 824  *
 825  * Simple function that handles the truncation of an eCryptfs inode and
 826  * its corresponding lower inode.
 827  *
 828  * Returns zero on success; non-zero otherwise
 829  */
 830 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 831 {
 832         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 833         struct iattr lower_ia = { .ia_valid = 0 };
 834         int rc;
 835
 836         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 837         if (rc)
 838                 return rc;
 839
 840         rc = truncate_upper(dentry, &ia, &lower_ia);
 841         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 842                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 843
 844                 inode_lock(d_inode(lower_dentry));
 845                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 846                 inode_unlock(d_inode(lower_dentry));
 847         }
 848         return rc;
 849 }
 850
 851 static int
 852 ecryptfs_permission(struct inode *inode, int mask)
 853 {
 854         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 855 }
 856
 857 /**
 858  * ecryptfs_setattr
 859  * @dentry: dentry handle to the inode to modify
 860  * @ia: Structure with flags of what to change and values
 861  *
 862  * Updates the metadata of an inode. If the update is to the size
 863  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 864  * of both the ecryptfs inode and the lower inode.
 865  *
 866  * All other metadata changes will be passed right to the lower filesystem,
 867  * and we will just update our inode to look like the lower.
 868  */
 869 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 870 {
 871         int rc = 0;
 872         struct dentry *lower_dentry;
 873         struct iattr lower_ia;
 874         struct inode *inode;
 875         struct inode *lower_inode;
 876         struct ecryptfs_crypt_stat *crypt_stat;
 877
 878         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 879         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
 880                 rc = ecryptfs_init_crypt_stat(crypt_stat);
 881                 if (rc)
 882                         return rc;
 883         }
 884         inode = d_inode(dentry);
 885         lower_inode = ecryptfs_inode_to_lower(inode);
 886         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 887         mutex_lock(&crypt_stat->cs_mutex);
 888         if (d_is_dir(dentry))
 889                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 890         else if (d_is_reg(dentry)
 891                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 892                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 893                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 894
 895                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 896                         dentry->d_sb)->mount_crypt_stat;
 897                 rc = ecryptfs_get_lower_file(dentry, inode);
 898                 if (rc) {
 899                         mutex_unlock(&crypt_stat->cs_mutex);
 900                         goto out;
 901                 }
 902                 rc = ecryptfs_read_metadata(dentry);
 903                 ecryptfs_put_lower_file(inode);
 904                 if (rc) {
 905                         if (!(mount_crypt_stat->flags
 906                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 907                                 rc = -EIO;
 908                                 printk(KERN_WARNING "Either the lower file "
 909                                        "is not in a valid eCryptfs format, "
 910                                        "or the key could not be retrieved. "
 911                                        "Plaintext passthrough mode is not "
 912                                        "enabled; returning -EIO\n");
 913                                 mutex_unlock(&crypt_stat->cs_mutex);
 914                                 goto out;
 915                         }
 916                         rc = 0;
 917                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 918                                                | ECRYPTFS_ENCRYPTED);
 919                 }
 920         }
 921         mutex_unlock(&crypt_stat->cs_mutex);
 922
 923         rc = setattr_prepare(dentry, ia);
 924         if (rc)
 925                 goto out;
 926         if (ia->ia_valid & ATTR_SIZE) {
 927                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 928                 if (rc)
 929                         goto out;
 930         }
 931
 932         memcpy(&lower_ia, ia, sizeof(lower_ia));
 933         if (ia->ia_valid & ATTR_FILE)
 934                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 935         if (ia->ia_valid & ATTR_SIZE) {
 936                 rc = truncate_upper(dentry, ia, &lower_ia);
 937                 if (rc < 0)
 938                         goto out;
 939         }
 940
 941         /*
 942          * mode change is for clearing setuid/setgid bits. Allow lower fs
 943          * to interpret this in its own way.
 944          */
 945         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 946                 lower_ia.ia_valid &= ~ATTR_MODE;
 947
 948         inode_lock(d_inode(lower_dentry));
 949         rc = notify_change(lower_dentry, &lower_ia, NULL);
 950         inode_unlock(d_inode(lower_dentry));
 951 out:
 952         fsstack_copy_attr_all(inode, lower_inode);
 953         return rc;
 954 }
 955
 956 static int ecryptfs_getattr_link(const struct path *path, struct kstat *stat,
 957                                  u32 request_mask, unsigned int flags)
 958 {
 959         struct dentry *dentry = path->dentry;
 960         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 961         int rc = 0;
 962
 963         mount_crypt_stat = &ecryptfs_superblock_to_private(
 964                                                 dentry->d_sb)->mount_crypt_stat;
 965         generic_fillattr(d_inode(dentry), stat);
 966         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 967                 char *target;
 968                 size_t targetsiz;
 969
 970                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 971                 if (!IS_ERR(target)) {
 972                         kfree(target);
 973                         stat->size = targetsiz;
 974                 } else {
 975                         rc = PTR_ERR(target);
 976                 }
 977         }
 978         return rc;
 979 }
 980
 981 static int ecryptfs_getattr(const struct path *path, struct kstat *stat,
 982                             u32 request_mask, unsigned int flags)
 983 {
 984         struct dentry *dentry = path->dentry;
 985         struct kstat lower_stat;
 986         int rc;
 987
 988         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
 989                          request_mask, flags);
 990         if (!rc) {
 991                 fsstack_copy_attr_all(d_inode(dentry),
 992                                       ecryptfs_inode_to_lower(d_inode(dentry)));
 993                 generic_fillattr(d_inode(dentry), stat);
 994                 stat->blocks = lower_stat.blocks;
 995         }
 996         return rc;
 997 }
 998
 999 int
1000 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1001                   const char *name, const void *value,
1002                   size_t size, int flags)
1003 {
1004         int rc;
1005         struct dentry *lower_dentry;
1006
1007         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1008         if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1009                 rc = -EOPNOTSUPP;
1010                 goto out;
1011         }
1012         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1013         if (!rc && inode)
1014                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1015 out:
1016         return rc;
1017 }
1018
1019 ssize_t
1020 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1021                         const char *name, void *value, size_t size)
1022 {
1023         int rc;
1024
1025         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1026                 rc = -EOPNOTSUPP;
1027                 goto out;
1028         }
1029         inode_lock(lower_inode);
1030         rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1031         inode_unlock(lower_inode);
1032 out:
1033         return rc;
1034 }
1035
1036 static ssize_t
1037 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1038                   const char *name, void *value, size_t size)
1039 {
1040         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1041                                        ecryptfs_inode_to_lower(inode),
1042                                        name, value, size);
1043 }
1044
1045 static ssize_t
1046 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1047 {
1048         int rc = 0;
1049         struct dentry *lower_dentry;
1050
1051         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1052         if (!d_inode(lower_dentry)->i_op->listxattr) {
1053                 rc = -EOPNOTSUPP;
1054                 goto out;
1055         }
1056         inode_lock(d_inode(lower_dentry));
1057         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1058         inode_unlock(d_inode(lower_dentry));
1059 out:
1060         return rc;
1061 }
1062
1063 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1064                                 const char *name)
1065 {
1066         int rc;
1067         struct dentry *lower_dentry;
1068         struct inode *lower_inode;
1069
1070         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1071         lower_inode = ecryptfs_inode_to_lower(inode);
1072         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1073                 rc = -EOPNOTSUPP;
1074                 goto out;
1075         }
1076         inode_lock(lower_inode);
1077         rc = __vfs_removexattr(lower_dentry, name);
1078         inode_unlock(lower_inode);
1079 out:
1080         return rc;
1081 }
1082
1083 const struct inode_operations ecryptfs_symlink_iops = {
1084         .get_link = ecryptfs_get_link,
1085         .permission = ecryptfs_permission,
1086         .setattr = ecryptfs_setattr,
1087         .getattr = ecryptfs_getattr_link,
1088         .listxattr = ecryptfs_listxattr,
1089 };
1090
1091 const struct inode_operations ecryptfs_dir_iops = {
1092         .create = ecryptfs_create,
1093         .lookup = ecryptfs_lookup,
1094         .link = ecryptfs_link,
1095         .unlink = ecryptfs_unlink,
1096         .symlink = ecryptfs_symlink,
1097         .mkdir = ecryptfs_mkdir,
1098         .rmdir = ecryptfs_rmdir,
1099         .mknod = ecryptfs_mknod,
1100         .rename = ecryptfs_rename,
1101         .permission = ecryptfs_permission,
1102         .setattr = ecryptfs_setattr,
1103         .listxattr = ecryptfs_listxattr,
1104 };
1105
1106 const struct inode_operations ecryptfs_main_iops = {
1107         .permission = ecryptfs_permission,
1108         .setattr = ecryptfs_setattr,
1109         .getattr = ecryptfs_getattr,
1110         .listxattr = ecryptfs_listxattr,
1111 };
1112
1113 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1114                               struct dentry *dentry, struct inode *inode,
1115                               const char *name, void *buffer, size_t size)
1116 {
1117         return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1118 }
1119
1120 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1121                               struct dentry *dentry, struct inode *inode,
1122                               const char *name, const void *value, size_t size,
1123                               int flags)
1124 {
1125         if (value)
1126                 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1127         else {
1128                 BUG_ON(flags != XATTR_REPLACE);
1129                 return ecryptfs_removexattr(dentry, inode, name);
1130         }
1131 }
1132
1133 const struct xattr_handler ecryptfs_xattr_handler = {
1134         .prefix = "",  /* match anything */
1135         .get = ecryptfs_xattr_get,
1136         .set = ecryptfs_xattr_set,
1137 };
1138
1139 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1140         &ecryptfs_xattr_handler,
1141         NULL
1142 };