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_version++;
  68         inode->i_mapping->a_ops = &ecryptfs_aops;
  69
  70         if (S_ISLNK(inode->i_mode))
  71                 inode->i_op = &ecryptfs_symlink_iops;
  72         else if (S_ISDIR(inode->i_mode))
  73                 inode->i_op = &ecryptfs_dir_iops;
  74         else
  75                 inode->i_op = &ecryptfs_main_iops;
  76
  77         if (S_ISDIR(inode->i_mode))
  78                 inode->i_fop = &ecryptfs_dir_fops;
  79         else if (special_file(inode->i_mode))
  80                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
  81         else
  82                 inode->i_fop = &ecryptfs_main_fops;
  83
  84         return 0;
  85 }
  86
  87 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  88                                           struct super_block *sb)
  89 {
  90         struct inode *inode;
  91
  92         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  93                 return ERR_PTR(-EXDEV);
  94         if (!igrab(lower_inode))
  95                 return ERR_PTR(-ESTALE);
  96         inode = iget5_locked(sb, (unsigned long)lower_inode,
  97                              ecryptfs_inode_test, ecryptfs_inode_set,
  98                              lower_inode);
  99         if (!inode) {
 100                 iput(lower_inode);
 101                 return ERR_PTR(-EACCES);
 102         }
 103         if (!(inode->i_state & I_NEW))
 104                 iput(lower_inode);
 105
 106         return inode;
 107 }
 108
 109 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 110                                  struct super_block *sb)
 111 {
 112         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 113
 114         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 115                 unlock_new_inode(inode);
 116
 117         return inode;
 118 }
 119
 120 /**
 121  * ecryptfs_interpose
 122  * @lower_dentry: Existing dentry in the lower filesystem
 123  * @dentry: ecryptfs' dentry
 124  * @sb: ecryptfs's super_block
 125  *
 126  * Interposes upper and lower dentries.
 127  *
 128  * Returns zero on success; non-zero otherwise
 129  */
 130 static int ecryptfs_interpose(struct dentry *lower_dentry,
 131                               struct dentry *dentry, struct super_block *sb)
 132 {
 133         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 134
 135         if (IS_ERR(inode))
 136                 return PTR_ERR(inode);
 137         d_instantiate(dentry, inode);
 138
 139         return 0;
 140 }
 141
 142 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 143                               struct inode *inode)
 144 {
 145         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 146         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 147         struct dentry *lower_dir_dentry;
 148         int rc;
 149
 150         dget(lower_dentry);
 151         lower_dir_dentry = lock_parent(lower_dentry);
 152         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 153         if (rc) {
 154                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 155                 goto out_unlock;
 156         }
 157         fsstack_copy_attr_times(dir, lower_dir_inode);
 158         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 159         inode->i_ctime = dir->i_ctime;
 160         d_drop(dentry);
 161 out_unlock:
 162         unlock_dir(lower_dir_dentry);
 163         dput(lower_dentry);
 164         return rc;
 165 }
 166
 167 /**
 168  * ecryptfs_do_create
 169  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 170  * @ecryptfs_dentry: New file's dentry in ecryptfs
 171  * @mode: The mode of the new file
 172  *
 173  * Creates the underlying file and the eCryptfs inode which will link to
 174  * it. It will also update the eCryptfs directory inode to mimic the
 175  * stat of the lower directory inode.
 176  *
 177  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 178  */
 179 static struct inode *
 180 ecryptfs_do_create(struct inode *directory_inode,
 181                    struct dentry *ecryptfs_dentry, umode_t mode)
 182 {
 183         int rc;
 184         struct dentry *lower_dentry;
 185         struct dentry *lower_dir_dentry;
 186         struct inode *inode;
 187
 188         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 189         lower_dir_dentry = lock_parent(lower_dentry);
 190         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 191         if (rc) {
 192                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 193                        "rc = [%d]\n", __func__, rc);
 194                 inode = ERR_PTR(rc);
 195                 goto out_lock;
 196         }
 197         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 198                                      directory_inode->i_sb);
 199         if (IS_ERR(inode)) {
 200                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 201                 goto out_lock;
 202         }
 203         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 204         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 205 out_lock:
 206         unlock_dir(lower_dir_dentry);
 207         return inode;
 208 }
 209
 210 /**
 211  * ecryptfs_initialize_file
 212  *
 213  * Cause the file to be changed from a basic empty file to an ecryptfs
 214  * file with a header and first data page.
 215  *
 216  * Returns zero on success
 217  */
 218 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 219                              struct inode *ecryptfs_inode)
 220 {
 221         struct ecryptfs_crypt_stat *crypt_stat =
 222                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 223         int rc = 0;
 224
 225         if (S_ISDIR(ecryptfs_inode->i_mode)) {
 226                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 227                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 228                 goto out;
 229         }
 230         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 231         rc = ecryptfs_new_file_context(ecryptfs_inode);
 232         if (rc) {
 233                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 234                                 "context; rc = [%d]\n", rc);
 235                 goto out;
 236         }
 237         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 238         if (rc) {
 239                 printk(KERN_ERR "%s: Error attempting to initialize "
 240                         "the lower file for the dentry with name "
 241                         "[%pd]; rc = [%d]\n", __func__,
 242                         ecryptfs_dentry, rc);
 243                 goto out;
 244         }
 245         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 246         if (rc)
 247                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 248         ecryptfs_put_lower_file(ecryptfs_inode);
 249 out:
 250         return rc;
 251 }
 252
 253 /**
 254  * ecryptfs_create
 255  * @dir: The inode of the directory in which to create the file.
 256  * @dentry: The eCryptfs dentry
 257  * @mode: The mode of the new file.
 258  *
 259  * Creates a new file.
 260  *
 261  * Returns zero on success; non-zero on error condition
 262  */
 263 static int
 264 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 265                 umode_t mode, bool excl)
 266 {
 267         struct inode *ecryptfs_inode;
 268         int rc;
 269
 270         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 271                                             mode);
 272         if (IS_ERR(ecryptfs_inode)) {
 273                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 274                                 "lower filesystem\n");
 275                 rc = PTR_ERR(ecryptfs_inode);
 276                 goto out;
 277         }
 278         /* At this point, a file exists on "disk"; we need to make sure
 279          * that this on disk file is prepared to be an ecryptfs file */
 280         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 281         if (rc) {
 282                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 283                                    ecryptfs_inode);
 284                 iget_failed(ecryptfs_inode);
 285                 goto out;
 286         }
 287         d_instantiate_new(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 path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
 330         struct inode *inode, *lower_inode;
 331         struct ecryptfs_dentry_info *dentry_info;
 332         int rc = 0;
 333
 334         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 335         if (!dentry_info) {
 336                 printk(KERN_ERR "%s: Out of memory whilst attempting "
 337                        "to allocate ecryptfs_dentry_info struct\n",
 338                         __func__);
 339                 dput(lower_dentry);
 340                 return ERR_PTR(-ENOMEM);
 341         }
 342
 343         fsstack_copy_attr_atime(d_inode(dentry->d_parent),
 344                                 d_inode(path->dentry));
 345         BUG_ON(!d_count(lower_dentry));
 346
 347         ecryptfs_set_dentry_private(dentry, dentry_info);
 348         dentry_info->lower_path.mnt = mntget(path->mnt);
 349         dentry_info->lower_path.dentry = lower_dentry;
 350
 351         /*
 352          * negative dentry can go positive under us here - its parent is not
 353          * locked.  That's OK and that could happen just as we return from
 354          * ecryptfs_lookup() anyway.  Just need to be careful and fetch
 355          * ->d_inode only once - it's not stable here.
 356          */
 357         lower_inode = READ_ONCE(lower_dentry->d_inode);
 358
 359         if (!lower_inode) {
 360                 /* We want to add because we couldn't find in lower */
 361                 d_add(dentry, NULL);
 362                 return NULL;
 363         }
 364         inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
 365         if (IS_ERR(inode)) {
 366                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 367                        __func__, PTR_ERR(inode));
 368                 return ERR_CAST(inode);
 369         }
 370         if (S_ISREG(inode->i_mode)) {
 371                 rc = ecryptfs_i_size_read(dentry, inode);
 372                 if (rc) {
 373                         make_bad_inode(inode);
 374                         return ERR_PTR(rc);
 375                 }
 376         }
 377
 378         if (inode->i_state & I_NEW)
 379                 unlock_new_inode(inode);
 380         return d_splice_alias(inode, dentry);
 381 }
 382
 383 /**
 384  * ecryptfs_lookup
 385  * @ecryptfs_dir_inode: The eCryptfs directory inode
 386  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 387  * @flags: lookup flags
 388  *
 389  * Find a file on disk. If the file does not exist, then we'll add it to the
 390  * dentry cache and continue on to read it from the disk.
 391  */
 392 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 393                                       struct dentry *ecryptfs_dentry,
 394                                       unsigned int flags)
 395 {
 396         char *encrypted_and_encoded_name = NULL;
 397         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 398         struct dentry *lower_dir_dentry, *lower_dentry;
 399         const char *name = ecryptfs_dentry->d_name.name;
 400         size_t len = ecryptfs_dentry->d_name.len;
 401         struct dentry *res;
 402         int rc = 0;
 403
 404         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 405
 406         mount_crypt_stat = &ecryptfs_superblock_to_private(
 407                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 408         if (mount_crypt_stat
 409             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
 410                 rc = ecryptfs_encrypt_and_encode_filename(
 411                         &encrypted_and_encoded_name, &len,
 412                         mount_crypt_stat, name, len);
 413                 if (rc) {
 414                         printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 415                                "filename; rc = [%d]\n", __func__, rc);
 416                         return ERR_PTR(rc);
 417                 }
 418                 name = encrypted_and_encoded_name;
 419         }
 420
 421         lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
 422         if (IS_ERR(lower_dentry)) {
 423                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 424                                 "[%ld] on lower_dentry = [%s]\n", __func__,
 425                                 PTR_ERR(lower_dentry),
 426                                 name);
 427                 res = ERR_CAST(lower_dentry);
 428         } else {
 429                 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
 430         }
 431         kfree(encrypted_and_encoded_name);
 432         return res;
 433 }
 434
 435 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 436                          struct dentry *new_dentry)
 437 {
 438         struct dentry *lower_old_dentry;
 439         struct dentry *lower_new_dentry;
 440         struct dentry *lower_dir_dentry;
 441         u64 file_size_save;
 442         int rc;
 443
 444         file_size_save = i_size_read(d_inode(old_dentry));
 445         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 446         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 447         dget(lower_old_dentry);
 448         dget(lower_new_dentry);
 449         lower_dir_dentry = lock_parent(lower_new_dentry);
 450         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 451                       lower_new_dentry, NULL);
 452         if (rc || d_really_is_negative(lower_new_dentry))
 453                 goto out_lock;
 454         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 455         if (rc)
 456                 goto out_lock;
 457         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 458         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 459         set_nlink(d_inode(old_dentry),
 460                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 461         i_size_write(d_inode(new_dentry), file_size_save);
 462 out_lock:
 463         unlock_dir(lower_dir_dentry);
 464         dput(lower_new_dentry);
 465         dput(lower_old_dentry);
 466         return rc;
 467 }
 468
 469 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 470 {
 471         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 472 }
 473
 474 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 475                             const char *symname)
 476 {
 477         int rc;
 478         struct dentry *lower_dentry;
 479         struct dentry *lower_dir_dentry;
 480         char *encoded_symname;
 481         size_t encoded_symlen;
 482         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 483
 484         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 485         dget(lower_dentry);
 486         lower_dir_dentry = lock_parent(lower_dentry);
 487         mount_crypt_stat = &ecryptfs_superblock_to_private(
 488                 dir->i_sb)->mount_crypt_stat;
 489         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 490                                                   &encoded_symlen,
 491                                                   mount_crypt_stat, symname,
 492                                                   strlen(symname));
 493         if (rc)
 494                 goto out_lock;
 495         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 496                          encoded_symname);
 497         kfree(encoded_symname);
 498         if (rc || d_really_is_negative(lower_dentry))
 499                 goto out_lock;
 500         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 501         if (rc)
 502                 goto out_lock;
 503         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 504         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 505 out_lock:
 506         unlock_dir(lower_dir_dentry);
 507         dput(lower_dentry);
 508         if (d_really_is_negative(dentry))
 509                 d_drop(dentry);
 510         return rc;
 511 }
 512
 513 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 514 {
 515         int rc;
 516         struct dentry *lower_dentry;
 517         struct dentry *lower_dir_dentry;
 518
 519         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 520         lower_dir_dentry = lock_parent(lower_dentry);
 521         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 522         if (rc || d_really_is_negative(lower_dentry))
 523                 goto out;
 524         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 525         if (rc)
 526                 goto out;
 527         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 528         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 529         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 530 out:
 531         unlock_dir(lower_dir_dentry);
 532         if (d_really_is_negative(dentry))
 533                 d_drop(dentry);
 534         return rc;
 535 }
 536
 537 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 538 {
 539         struct dentry *lower_dentry;
 540         struct dentry *lower_dir_dentry;
 541         int rc;
 542
 543         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 544         dget(dentry);
 545         lower_dir_dentry = lock_parent(lower_dentry);
 546         dget(lower_dentry);
 547         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 548         dput(lower_dentry);
 549         if (!rc && d_really_is_positive(dentry))
 550                 clear_nlink(d_inode(dentry));
 551         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 552         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 553         unlock_dir(lower_dir_dentry);
 554         if (!rc)
 555                 d_drop(dentry);
 556         dput(dentry);
 557         return rc;
 558 }
 559
 560 static int
 561 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 562 {
 563         int rc;
 564         struct dentry *lower_dentry;
 565         struct dentry *lower_dir_dentry;
 566
 567         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 568         lower_dir_dentry = lock_parent(lower_dentry);
 569         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 570         if (rc || d_really_is_negative(lower_dentry))
 571                 goto out;
 572         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 573         if (rc)
 574                 goto out;
 575         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 576         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 577 out:
 578         unlock_dir(lower_dir_dentry);
 579         if (d_really_is_negative(dentry))
 580                 d_drop(dentry);
 581         return rc;
 582 }
 583
 584 static int
 585 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 586                 struct inode *new_dir, struct dentry *new_dentry,
 587                 unsigned int flags)
 588 {
 589         int rc;
 590         struct dentry *lower_old_dentry;
 591         struct dentry *lower_new_dentry;
 592         struct dentry *lower_old_dir_dentry;
 593         struct dentry *lower_new_dir_dentry;
 594         struct dentry *trap = NULL;
 595         struct inode *target_inode;
 596
 597         if (flags)
 598                 return -EINVAL;
 599
 600         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 601         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 602         dget(lower_old_dentry);
 603         dget(lower_new_dentry);
 604         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 605         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 606         target_inode = d_inode(new_dentry);
 607         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 608         /* source should not be ancestor of target */
 609         if (trap == lower_old_dentry) {
 610                 rc = -EINVAL;
 611                 goto out_lock;
 612         }
 613         /* target should not be ancestor of source */
 614         if (trap == lower_new_dentry) {
 615                 rc = -ENOTEMPTY;
 616                 goto out_lock;
 617         }
 618         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 619                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 620                         NULL, 0);
 621         if (rc)
 622                 goto out_lock;
 623         if (target_inode)
 624                 fsstack_copy_attr_all(target_inode,
 625                                       ecryptfs_inode_to_lower(target_inode));
 626         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 627         if (new_dir != old_dir)
 628                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 629 out_lock:
 630         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 631         dput(lower_new_dir_dentry);
 632         dput(lower_old_dir_dentry);
 633         dput(lower_new_dentry);
 634         dput(lower_old_dentry);
 635         return rc;
 636 }
 637
 638 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 639 {
 640         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 641         char *lower_buf;
 642         char *buf;
 643         mm_segment_t old_fs;
 644         int rc;
 645
 646         lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
 647         if (!lower_buf)
 648                 return ERR_PTR(-ENOMEM);
 649         old_fs = get_fs();
 650         set_fs(get_ds());
 651         rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
 652                                                    (char __user *)lower_buf,
 653                                                    PATH_MAX);
 654         set_fs(old_fs);
 655         if (rc < 0)
 656                 goto out;
 657         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 658                                                   lower_buf, rc);
 659 out:
 660         kfree(lower_buf);
 661         return rc ? ERR_PTR(rc) : buf;
 662 }
 663
 664 static const char *ecryptfs_get_link(struct dentry *dentry,
 665                                      struct inode *inode,
 666                                      struct delayed_call *done)
 667 {
 668         size_t len;
 669         char *buf;
 670
 671         if (!dentry)
 672                 return ERR_PTR(-ECHILD);
 673
 674         buf = ecryptfs_readlink_lower(dentry, &len);
 675         if (IS_ERR(buf))
 676                 return buf;
 677         fsstack_copy_attr_atime(d_inode(dentry),
 678                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 679         buf[len] = '\0';
 680         set_delayed_call(done, kfree_link, buf);
 681         return buf;
 682 }
 683
 684 /**
 685  * upper_size_to_lower_size
 686  * @crypt_stat: Crypt_stat associated with file
 687  * @upper_size: Size of the upper file
 688  *
 689  * Calculate the required size of the lower file based on the
 690  * specified size of the upper file. This calculation is based on the
 691  * number of headers in the underlying file and the extent size.
 692  *
 693  * Returns Calculated size of the lower file.
 694  */
 695 static loff_t
 696 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 697                          loff_t upper_size)
 698 {
 699         loff_t lower_size;
 700
 701         lower_size = ecryptfs_lower_header_size(crypt_stat);
 702         if (upper_size != 0) {
 703                 loff_t num_extents;
 704
 705                 num_extents = upper_size >> crypt_stat->extent_shift;
 706                 if (upper_size & ~crypt_stat->extent_mask)
 707                         num_extents++;
 708                 lower_size += (num_extents * crypt_stat->extent_size);
 709         }
 710         return lower_size;
 711 }
 712
 713 /**
 714  * truncate_upper
 715  * @dentry: The ecryptfs layer dentry
 716  * @ia: Address of the ecryptfs inode's attributes
 717  * @lower_ia: Address of the lower inode's attributes
 718  *
 719  * Function to handle truncations modifying the size of the file. Note
 720  * that the file sizes are interpolated. When expanding, we are simply
 721  * writing strings of 0's out. When truncating, we truncate the upper
 722  * inode and update the lower_ia according to the page index
 723  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 724  * the caller must use lower_ia in a call to notify_change() to perform
 725  * the truncation of the lower inode.
 726  *
 727  * Returns zero on success; non-zero otherwise
 728  */
 729 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 730                           struct iattr *lower_ia)
 731 {
 732         int rc = 0;
 733         struct inode *inode = d_inode(dentry);
 734         struct ecryptfs_crypt_stat *crypt_stat;
 735         loff_t i_size = i_size_read(inode);
 736         loff_t lower_size_before_truncate;
 737         loff_t lower_size_after_truncate;
 738
 739         if (unlikely((ia->ia_size == i_size))) {
 740                 lower_ia->ia_valid &= ~ATTR_SIZE;
 741                 return 0;
 742         }
 743         rc = ecryptfs_get_lower_file(dentry, inode);
 744         if (rc)
 745                 return rc;
 746         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 747         /* Switch on growing or shrinking file */
 748         if (ia->ia_size > i_size) {
 749                 char zero[] = { 0x00 };
 750
 751                 lower_ia->ia_valid &= ~ATTR_SIZE;
 752                 /* Write a single 0 at the last position of the file;
 753                  * this triggers code that will fill in 0's throughout
 754                  * the intermediate portion of the previous end of the
 755                  * file and the new and of the file */
 756                 rc = ecryptfs_write(inode, zero,
 757                                     (ia->ia_size - 1), 1);
 758         } else { /* ia->ia_size < i_size_read(inode) */
 759                 /* We're chopping off all the pages down to the page
 760                  * in which ia->ia_size is located. Fill in the end of
 761                  * that page from (ia->ia_size & ~PAGE_MASK) to
 762                  * PAGE_SIZE with zeros. */
 763                 size_t num_zeros = (PAGE_SIZE
 764                                     - (ia->ia_size & ~PAGE_MASK));
 765
 766                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 767                         truncate_setsize(inode, ia->ia_size);
 768                         lower_ia->ia_size = ia->ia_size;
 769                         lower_ia->ia_valid |= ATTR_SIZE;
 770                         goto out;
 771                 }
 772                 if (num_zeros) {
 773                         char *zeros_virt;
 774
 775                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 776                         if (!zeros_virt) {
 777                                 rc = -ENOMEM;
 778                                 goto out;
 779                         }
 780                         rc = ecryptfs_write(inode, zeros_virt,
 781                                             ia->ia_size, num_zeros);
 782                         kfree(zeros_virt);
 783                         if (rc) {
 784                                 printk(KERN_ERR "Error attempting to zero out "
 785                                        "the remainder of the end page on "
 786                                        "reducing truncate; rc = [%d]\n", rc);
 787                                 goto out;
 788                         }
 789                 }
 790                 truncate_setsize(inode, ia->ia_size);
 791                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 792                 if (rc) {
 793                         printk(KERN_ERR "Problem with "
 794                                "ecryptfs_write_inode_size_to_metadata; "
 795                                "rc = [%d]\n", rc);
 796                         goto out;
 797                 }
 798                 /* We are reducing the size of the ecryptfs file, and need to
 799                  * know if we need to reduce the size of the lower file. */
 800                 lower_size_before_truncate =
 801                     upper_size_to_lower_size(crypt_stat, i_size);
 802                 lower_size_after_truncate =
 803                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 804                 if (lower_size_after_truncate < lower_size_before_truncate) {
 805                         lower_ia->ia_size = lower_size_after_truncate;
 806                         lower_ia->ia_valid |= ATTR_SIZE;
 807                 } else
 808                         lower_ia->ia_valid &= ~ATTR_SIZE;
 809         }
 810 out:
 811         ecryptfs_put_lower_file(inode);
 812         return rc;
 813 }
 814
 815 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 816 {
 817         struct ecryptfs_crypt_stat *crypt_stat;
 818         loff_t lower_oldsize, lower_newsize;
 819
 820         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 821         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 822                                                  i_size_read(inode));
 823         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 824         if (lower_newsize > lower_oldsize) {
 825                 /*
 826                  * The eCryptfs inode and the new *lower* size are mixed here
 827                  * because we may not have the lower i_mutex held and/or it may
 828                  * not be appropriate to call inode_newsize_ok() with inodes
 829                  * from other filesystems.
 830                  */
 831                 return inode_newsize_ok(inode, lower_newsize);
 832         }
 833
 834         return 0;
 835 }
 836
 837 /**
 838  * ecryptfs_truncate
 839  * @dentry: The ecryptfs layer dentry
 840  * @new_length: The length to expand the file to
 841  *
 842  * Simple function that handles the truncation of an eCryptfs inode and
 843  * its corresponding lower inode.
 844  *
 845  * Returns zero on success; non-zero otherwise
 846  */
 847 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 848 {
 849         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 850         struct iattr lower_ia = { .ia_valid = 0 };
 851         int rc;
 852
 853         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 854         if (rc)
 855                 return rc;
 856
 857         rc = truncate_upper(dentry, &ia, &lower_ia);
 858         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 859                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 860
 861                 inode_lock(d_inode(lower_dentry));
 862                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 863                 inode_unlock(d_inode(lower_dentry));
 864         }
 865         return rc;
 866 }
 867
 868 static int
 869 ecryptfs_permission(struct inode *inode, int mask)
 870 {
 871         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 872 }
 873
 874 /**
 875  * ecryptfs_setattr
 876  * @dentry: dentry handle to the inode to modify
 877  * @ia: Structure with flags of what to change and values
 878  *
 879  * Updates the metadata of an inode. If the update is to the size
 880  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 881  * of both the ecryptfs inode and the lower inode.
 882  *
 883  * All other metadata changes will be passed right to the lower filesystem,
 884  * and we will just update our inode to look like the lower.
 885  */
 886 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 887 {
 888         int rc = 0;
 889         struct dentry *lower_dentry;
 890         struct iattr lower_ia;
 891         struct inode *inode;
 892         struct inode *lower_inode;
 893         struct ecryptfs_crypt_stat *crypt_stat;
 894
 895         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 896         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
 897                 rc = ecryptfs_init_crypt_stat(crypt_stat);
 898                 if (rc)
 899                         return rc;
 900         }
 901         inode = d_inode(dentry);
 902         lower_inode = ecryptfs_inode_to_lower(inode);
 903         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 904         mutex_lock(&crypt_stat->cs_mutex);
 905         if (d_is_dir(dentry))
 906                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 907         else if (d_is_reg(dentry)
 908                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 909                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 910                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 911
 912                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 913                         dentry->d_sb)->mount_crypt_stat;
 914                 rc = ecryptfs_get_lower_file(dentry, inode);
 915                 if (rc) {
 916                         mutex_unlock(&crypt_stat->cs_mutex);
 917                         goto out;
 918                 }
 919                 rc = ecryptfs_read_metadata(dentry);
 920                 ecryptfs_put_lower_file(inode);
 921                 if (rc) {
 922                         if (!(mount_crypt_stat->flags
 923                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 924                                 rc = -EIO;
 925                                 printk(KERN_WARNING "Either the lower file "
 926                                        "is not in a valid eCryptfs format, "
 927                                        "or the key could not be retrieved. "
 928                                        "Plaintext passthrough mode is not "
 929                                        "enabled; returning -EIO\n");
 930                                 mutex_unlock(&crypt_stat->cs_mutex);
 931                                 goto out;
 932                         }
 933                         rc = 0;
 934                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 935                                                | ECRYPTFS_ENCRYPTED);
 936                 }
 937         }
 938         mutex_unlock(&crypt_stat->cs_mutex);
 939
 940         rc = setattr_prepare(dentry, ia);
 941         if (rc)
 942                 goto out;
 943         if (ia->ia_valid & ATTR_SIZE) {
 944                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 945                 if (rc)
 946                         goto out;
 947         }
 948
 949         memcpy(&lower_ia, ia, sizeof(lower_ia));
 950         if (ia->ia_valid & ATTR_FILE)
 951                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 952         if (ia->ia_valid & ATTR_SIZE) {
 953                 rc = truncate_upper(dentry, ia, &lower_ia);
 954                 if (rc < 0)
 955                         goto out;
 956         }
 957
 958         /*
 959          * mode change is for clearing setuid/setgid bits. Allow lower fs
 960          * to interpret this in its own way.
 961          */
 962         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 963                 lower_ia.ia_valid &= ~ATTR_MODE;
 964
 965         inode_lock(d_inode(lower_dentry));
 966         rc = notify_change(lower_dentry, &lower_ia, NULL);
 967         inode_unlock(d_inode(lower_dentry));
 968 out:
 969         fsstack_copy_attr_all(inode, lower_inode);
 970         return rc;
 971 }
 972
 973 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
 974                                  struct kstat *stat)
 975 {
 976         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 977         int rc = 0;
 978
 979         mount_crypt_stat = &ecryptfs_superblock_to_private(
 980                                                 dentry->d_sb)->mount_crypt_stat;
 981         generic_fillattr(d_inode(dentry), stat);
 982         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 983                 char *target;
 984                 size_t targetsiz;
 985
 986                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 987                 if (!IS_ERR(target)) {
 988                         kfree(target);
 989                         stat->size = targetsiz;
 990                 } else {
 991                         rc = PTR_ERR(target);
 992                 }
 993         }
 994         return rc;
 995 }
 996
 997 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 998                             struct kstat *stat)
 999 {
1000         struct kstat lower_stat;
1001         int rc;
1002
1003         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
1004         if (!rc) {
1005                 fsstack_copy_attr_all(d_inode(dentry),
1006                                       ecryptfs_inode_to_lower(d_inode(dentry)));
1007                 generic_fillattr(d_inode(dentry), stat);
1008                 stat->blocks = lower_stat.blocks;
1009         }
1010         return rc;
1011 }
1012
1013 int
1014 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1015                   const char *name, const void *value,
1016                   size_t size, int flags)
1017 {
1018         int rc;
1019         struct dentry *lower_dentry;
1020
1021         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1022         if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1023                 rc = -EOPNOTSUPP;
1024                 goto out;
1025         }
1026         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1027         if (!rc && inode)
1028                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1029 out:
1030         return rc;
1031 }
1032
1033 ssize_t
1034 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1035                         const char *name, void *value, size_t size)
1036 {
1037         int rc;
1038
1039         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1040                 rc = -EOPNOTSUPP;
1041                 goto out;
1042         }
1043         inode_lock(lower_inode);
1044         rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1045         inode_unlock(lower_inode);
1046 out:
1047         return rc;
1048 }
1049
1050 static ssize_t
1051 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1052                   const char *name, void *value, size_t size)
1053 {
1054         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1055                                        ecryptfs_inode_to_lower(inode),
1056                                        name, value, size);
1057 }
1058
1059 static ssize_t
1060 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1061 {
1062         int rc = 0;
1063         struct dentry *lower_dentry;
1064
1065         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1066         if (!d_inode(lower_dentry)->i_op->listxattr) {
1067                 rc = -EOPNOTSUPP;
1068                 goto out;
1069         }
1070         inode_lock(d_inode(lower_dentry));
1071         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1072         inode_unlock(d_inode(lower_dentry));
1073 out:
1074         return rc;
1075 }
1076
1077 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1078                                 const char *name)
1079 {
1080         int rc;
1081         struct dentry *lower_dentry;
1082         struct inode *lower_inode;
1083
1084         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1085         lower_inode = ecryptfs_inode_to_lower(inode);
1086         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1087                 rc = -EOPNOTSUPP;
1088                 goto out;
1089         }
1090         inode_lock(lower_inode);
1091         rc = __vfs_removexattr(lower_dentry, name);
1092         inode_unlock(lower_inode);
1093 out:
1094         return rc;
1095 }
1096
1097 const struct inode_operations ecryptfs_symlink_iops = {
1098         .readlink = generic_readlink,
1099         .get_link = ecryptfs_get_link,
1100         .permission = ecryptfs_permission,
1101         .setattr = ecryptfs_setattr,
1102         .getattr = ecryptfs_getattr_link,
1103         .listxattr = ecryptfs_listxattr,
1104 };
1105
1106 const struct inode_operations ecryptfs_dir_iops = {
1107         .create = ecryptfs_create,
1108         .lookup = ecryptfs_lookup,
1109         .link = ecryptfs_link,
1110         .unlink = ecryptfs_unlink,
1111         .symlink = ecryptfs_symlink,
1112         .mkdir = ecryptfs_mkdir,
1113         .rmdir = ecryptfs_rmdir,
1114         .mknod = ecryptfs_mknod,
1115         .rename = ecryptfs_rename,
1116         .permission = ecryptfs_permission,
1117         .setattr = ecryptfs_setattr,
1118         .listxattr = ecryptfs_listxattr,
1119 };
1120
1121 const struct inode_operations ecryptfs_main_iops = {
1122         .permission = ecryptfs_permission,
1123         .setattr = ecryptfs_setattr,
1124         .getattr = ecryptfs_getattr,
1125         .listxattr = ecryptfs_listxattr,
1126 };
1127
1128 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1129                               struct dentry *dentry, struct inode *inode,
1130                               const char *name, void *buffer, size_t size)
1131 {
1132         return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1133 }
1134
1135 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1136                               struct dentry *dentry, struct inode *inode,
1137                               const char *name, const void *value, size_t size,
1138                               int flags)
1139 {
1140         if (value)
1141                 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1142         else {
1143                 BUG_ON(flags != XATTR_REPLACE);
1144                 return ecryptfs_removexattr(dentry, inode, name);
1145         }
1146 }
1147
1148 const struct xattr_handler ecryptfs_xattr_handler = {
1149         .prefix = "",  /* match anything */
1150         .get = ecryptfs_xattr_get,
1151         .set = ecryptfs_xattr_set,
1152 };
1153
1154 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1155         &ecryptfs_xattr_handler,
1156         NULL
1157 };