fs/ecryptfs/inode.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2004 Erez Zadok
   5  * Copyright (C) 2001-2004 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #include <linux/file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/dcache.h>
  30 #include <linux/namei.h>
  31 #include <linux/mount.h>
  32 #include <linux/crypto.h>
  33 #include <linux/fs_stack.h>
  34 #include <linux/slab.h>
  35 #include <linux/xattr.h>
  36 #include <asm/unaligned.h>
  37 #include "ecryptfs_kernel.h"
  38
  39 static struct dentry *lock_parent(struct dentry *dentry)
  40 {
  41         struct dentry *dir;
  42
  43         dir = dget_parent(dentry);
  44         inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
  45         return dir;
  46 }
  47
  48 static void unlock_dir(struct dentry *dir)
  49 {
  50         inode_unlock(d_inode(dir));
  51         dput(dir);
  52 }
  53
  54 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
  55 {
  56         return ecryptfs_inode_to_lower(inode) == lower_inode;
  57 }
  58
  59 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
  60 {
  61         struct inode *lower_inode = opaque;
  62
  63         ecryptfs_set_inode_lower(inode, lower_inode);
  64         fsstack_copy_attr_all(inode, lower_inode);
  65         /* i_size will be overwritten for encrypted regular files */
  66         fsstack_copy_inode_size(inode, lower_inode);
  67         inode->i_ino = lower_inode->i_ino;
  68         inode->i_version++;
  69         inode->i_mapping->a_ops = &ecryptfs_aops;
  70
  71         if (S_ISLNK(inode->i_mode))
  72                 inode->i_op = &ecryptfs_symlink_iops;
  73         else if (S_ISDIR(inode->i_mode))
  74                 inode->i_op = &ecryptfs_dir_iops;
  75         else
  76                 inode->i_op = &ecryptfs_main_iops;
  77
  78         if (S_ISDIR(inode->i_mode))
  79                 inode->i_fop = &ecryptfs_dir_fops;
  80         else if (special_file(inode->i_mode))
  81                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
  82         else
  83                 inode->i_fop = &ecryptfs_main_fops;
  84
  85         return 0;
  86 }
  87
  88 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  89                                           struct super_block *sb)
  90 {
  91         struct inode *inode;
  92
  93         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  94                 return ERR_PTR(-EXDEV);
  95         if (!igrab(lower_inode))
  96                 return ERR_PTR(-ESTALE);
  97         inode = iget5_locked(sb, (unsigned long)lower_inode,
  98                              ecryptfs_inode_test, ecryptfs_inode_set,
  99                              lower_inode);
 100         if (!inode) {
 101                 iput(lower_inode);
 102                 return ERR_PTR(-EACCES);
 103         }
 104         if (!(inode->i_state & I_NEW))
 105                 iput(lower_inode);
 106
 107         return inode;
 108 }
 109
 110 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 111                                  struct super_block *sb)
 112 {
 113         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 114
 115         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 116                 unlock_new_inode(inode);
 117
 118         return inode;
 119 }
 120
 121 /**
 122  * ecryptfs_interpose
 123  * @lower_dentry: Existing dentry in the lower filesystem
 124  * @dentry: ecryptfs' dentry
 125  * @sb: ecryptfs's super_block
 126  *
 127  * Interposes upper and lower dentries.
 128  *
 129  * Returns zero on success; non-zero otherwise
 130  */
 131 static int ecryptfs_interpose(struct dentry *lower_dentry,
 132                               struct dentry *dentry, struct super_block *sb)
 133 {
 134         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 135
 136         if (IS_ERR(inode))
 137                 return PTR_ERR(inode);
 138         d_instantiate(dentry, inode);
 139
 140         return 0;
 141 }
 142
 143 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 144                               struct inode *inode)
 145 {
 146         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 147         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 148         struct dentry *lower_dir_dentry;
 149         int rc;
 150
 151         dget(lower_dentry);
 152         lower_dir_dentry = lock_parent(lower_dentry);
 153         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 154         if (rc) {
 155                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 156                 goto out_unlock;
 157         }
 158         fsstack_copy_attr_times(dir, lower_dir_inode);
 159         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 160         inode->i_ctime = dir->i_ctime;
 161         d_drop(dentry);
 162 out_unlock:
 163         unlock_dir(lower_dir_dentry);
 164         dput(lower_dentry);
 165         return rc;
 166 }
 167
 168 /**
 169  * ecryptfs_do_create
 170  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 171  * @ecryptfs_dentry: New file's dentry in ecryptfs
 172  * @mode: The mode of the new file
 173  *
 174  * Creates the underlying file and the eCryptfs inode which will link to
 175  * it. It will also update the eCryptfs directory inode to mimic the
 176  * stat of the lower directory inode.
 177  *
 178  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 179  */
 180 static struct inode *
 181 ecryptfs_do_create(struct inode *directory_inode,
 182                    struct dentry *ecryptfs_dentry, umode_t mode)
 183 {
 184         int rc;
 185         struct dentry *lower_dentry;
 186         struct dentry *lower_dir_dentry;
 187         struct inode *inode;
 188
 189         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 190         lower_dir_dentry = lock_parent(lower_dentry);
 191         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 192         if (rc) {
 193                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 194                        "rc = [%d]\n", __func__, rc);
 195                 inode = ERR_PTR(rc);
 196                 goto out_lock;
 197         }
 198         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 199                                      directory_inode->i_sb);
 200         if (IS_ERR(inode)) {
 201                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 202                 goto out_lock;
 203         }
 204         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 205         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 206 out_lock:
 207         unlock_dir(lower_dir_dentry);
 208         return inode;
 209 }
 210
 211 /**
 212  * ecryptfs_initialize_file
 213  *
 214  * Cause the file to be changed from a basic empty file to an ecryptfs
 215  * file with a header and first data page.
 216  *
 217  * Returns zero on success
 218  */
 219 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 220                              struct inode *ecryptfs_inode)
 221 {
 222         struct ecryptfs_crypt_stat *crypt_stat =
 223                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 224         int rc = 0;
 225
 226         if (S_ISDIR(ecryptfs_inode->i_mode)) {
 227                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 228                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 229                 goto out;
 230         }
 231         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 232         rc = ecryptfs_new_file_context(ecryptfs_inode);
 233         if (rc) {
 234                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 235                                 "context; rc = [%d]\n", rc);
 236                 goto out;
 237         }
 238         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 239         if (rc) {
 240                 printk(KERN_ERR "%s: Error attempting to initialize "
 241                         "the lower file for the dentry with name "
 242                         "[%pd]; rc = [%d]\n", __func__,
 243                         ecryptfs_dentry, rc);
 244                 goto out;
 245         }
 246         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 247         if (rc)
 248                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 249         ecryptfs_put_lower_file(ecryptfs_inode);
 250 out:
 251         return rc;
 252 }
 253
 254 /**
 255  * ecryptfs_create
 256  * @dir: The inode of the directory in which to create the file.
 257  * @dentry: The eCryptfs dentry
 258  * @mode: The mode of the new file.
 259  *
 260  * Creates a new file.
 261  *
 262  * Returns zero on success; non-zero on error condition
 263  */
 264 static int
 265 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 266                 umode_t mode, bool excl)
 267 {
 268         struct inode *ecryptfs_inode;
 269         int rc;
 270
 271         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 272                                             mode);
 273         if (IS_ERR(ecryptfs_inode)) {
 274                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 275                                 "lower filesystem\n");
 276                 rc = PTR_ERR(ecryptfs_inode);
 277                 goto out;
 278         }
 279         /* At this point, a file exists on "disk"; we need to make sure
 280          * that this on disk file is prepared to be an ecryptfs file */
 281         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 282         if (rc) {
 283                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 284                                    ecryptfs_inode);
 285                 iget_failed(ecryptfs_inode);
 286                 goto out;
 287         }
 288         unlock_new_inode(ecryptfs_inode);
 289         d_instantiate(ecryptfs_dentry, ecryptfs_inode);
 290 out:
 291         return rc;
 292 }
 293
 294 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 295 {
 296         struct ecryptfs_crypt_stat *crypt_stat;
 297         int rc;
 298
 299         rc = ecryptfs_get_lower_file(dentry, inode);
 300         if (rc) {
 301                 printk(KERN_ERR "%s: Error attempting to initialize "
 302                         "the lower file for the dentry with name "
 303                         "[%pd]; rc = [%d]\n", __func__,
 304                         dentry, rc);
 305                 return rc;
 306         }
 307
 308         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 309         /* TODO: lock for crypt_stat comparison */
 310         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 311                 ecryptfs_set_default_sizes(crypt_stat);
 312
 313         rc = ecryptfs_read_and_validate_header_region(inode);
 314         ecryptfs_put_lower_file(inode);
 315         if (rc) {
 316                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
 317                 if (!rc)
 318                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 319         }
 320
 321         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
 322         return 0;
 323 }
 324
 325 /**
 326  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 327  */
 328 static int ecryptfs_lookup_interpose(struct dentry *dentry,
 329                                      struct dentry *lower_dentry,
 330                                      struct inode *dir_inode)
 331 {
 332         struct inode *inode, *lower_inode = d_inode(lower_dentry);
 333         struct ecryptfs_dentry_info *dentry_info;
 334         struct vfsmount *lower_mnt;
 335         int rc = 0;
 336
 337         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 338         if (!dentry_info) {
 339                 printk(KERN_ERR "%s: Out of memory whilst attempting "
 340                        "to allocate ecryptfs_dentry_info struct\n",
 341                         __func__);
 342                 dput(lower_dentry);
 343                 return -ENOMEM;
 344         }
 345
 346         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 347         fsstack_copy_attr_atime(dir_inode, d_inode(lower_dentry->d_parent));
 348         BUG_ON(!d_count(lower_dentry));
 349
 350         ecryptfs_set_dentry_private(dentry, dentry_info);
 351         dentry_info->lower_path.mnt = lower_mnt;
 352         dentry_info->lower_path.dentry = lower_dentry;
 353
 354         if (d_really_is_negative(lower_dentry)) {
 355                 /* We want to add because we couldn't find in lower */
 356                 d_add(dentry, NULL);
 357                 return 0;
 358         }
 359         inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
 360         if (IS_ERR(inode)) {
 361                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 362                        __func__, PTR_ERR(inode));
 363                 return PTR_ERR(inode);
 364         }
 365         if (S_ISREG(inode->i_mode)) {
 366                 rc = ecryptfs_i_size_read(dentry, inode);
 367                 if (rc) {
 368                         make_bad_inode(inode);
 369                         return rc;
 370                 }
 371         }
 372
 373         if (inode->i_state & I_NEW)
 374                 unlock_new_inode(inode);
 375         d_add(dentry, inode);
 376
 377         return rc;
 378 }
 379
 380 /**
 381  * ecryptfs_lookup
 382  * @ecryptfs_dir_inode: The eCryptfs directory inode
 383  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 384  * @flags: lookup flags
 385  *
 386  * Find a file on disk. If the file does not exist, then we'll add it to the
 387  * dentry cache and continue on to read it from the disk.
 388  */
 389 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 390                                       struct dentry *ecryptfs_dentry,
 391                                       unsigned int flags)
 392 {
 393         char *encrypted_and_encoded_name = NULL;
 394         size_t encrypted_and_encoded_name_size;
 395         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 396         struct dentry *lower_dir_dentry, *lower_dentry;
 397         int rc = 0;
 398
 399         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 400         inode_lock(d_inode(lower_dir_dentry));
 401         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
 402                                       lower_dir_dentry,
 403                                       ecryptfs_dentry->d_name.len);
 404         inode_unlock(d_inode(lower_dir_dentry));
 405         if (IS_ERR(lower_dentry)) {
 406                 rc = PTR_ERR(lower_dentry);
 407                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 408                                 "[%d] on lower_dentry = [%pd]\n", __func__, rc,
 409                                 ecryptfs_dentry);
 410                 goto out;
 411         }
 412         if (d_really_is_positive(lower_dentry))
 413                 goto interpose;
 414         mount_crypt_stat = &ecryptfs_superblock_to_private(
 415                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 416         if (!(mount_crypt_stat
 417             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
 418                 goto interpose;
 419         dput(lower_dentry);
 420         rc = ecryptfs_encrypt_and_encode_filename(
 421                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
 422                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
 423                 ecryptfs_dentry->d_name.len);
 424         if (rc) {
 425                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 426                        "filename; rc = [%d]\n", __func__, rc);
 427                 goto out;
 428         }
 429         inode_lock(d_inode(lower_dir_dentry));
 430         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
 431                                       lower_dir_dentry,
 432                                       encrypted_and_encoded_name_size);
 433         inode_unlock(d_inode(lower_dir_dentry));
 434         if (IS_ERR(lower_dentry)) {
 435                 rc = PTR_ERR(lower_dentry);
 436                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 437                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
 438                                 encrypted_and_encoded_name);
 439                 goto out;
 440         }
 441 interpose:
 442         rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
 443                                        ecryptfs_dir_inode);
 444 out:
 445         kfree(encrypted_and_encoded_name);
 446         return ERR_PTR(rc);
 447 }
 448
 449 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 450                          struct dentry *new_dentry)
 451 {
 452         struct dentry *lower_old_dentry;
 453         struct dentry *lower_new_dentry;
 454         struct dentry *lower_dir_dentry;
 455         u64 file_size_save;
 456         int rc;
 457
 458         file_size_save = i_size_read(d_inode(old_dentry));
 459         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 460         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 461         dget(lower_old_dentry);
 462         dget(lower_new_dentry);
 463         lower_dir_dentry = lock_parent(lower_new_dentry);
 464         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 465                       lower_new_dentry, NULL);
 466         if (rc || d_really_is_negative(lower_new_dentry))
 467                 goto out_lock;
 468         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 469         if (rc)
 470                 goto out_lock;
 471         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 472         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 473         set_nlink(d_inode(old_dentry),
 474                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 475         i_size_write(d_inode(new_dentry), file_size_save);
 476 out_lock:
 477         unlock_dir(lower_dir_dentry);
 478         dput(lower_new_dentry);
 479         dput(lower_old_dentry);
 480         return rc;
 481 }
 482
 483 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 484 {
 485         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 486 }
 487
 488 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 489                             const char *symname)
 490 {
 491         int rc;
 492         struct dentry *lower_dentry;
 493         struct dentry *lower_dir_dentry;
 494         char *encoded_symname;
 495         size_t encoded_symlen;
 496         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 497
 498         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 499         dget(lower_dentry);
 500         lower_dir_dentry = lock_parent(lower_dentry);
 501         mount_crypt_stat = &ecryptfs_superblock_to_private(
 502                 dir->i_sb)->mount_crypt_stat;
 503         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 504                                                   &encoded_symlen,
 505                                                   NULL,
 506                                                   mount_crypt_stat, symname,
 507                                                   strlen(symname));
 508         if (rc)
 509                 goto out_lock;
 510         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 511                          encoded_symname);
 512         kfree(encoded_symname);
 513         if (rc || d_really_is_negative(lower_dentry))
 514                 goto out_lock;
 515         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 516         if (rc)
 517                 goto out_lock;
 518         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 519         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 520 out_lock:
 521         unlock_dir(lower_dir_dentry);
 522         dput(lower_dentry);
 523         if (d_really_is_negative(dentry))
 524                 d_drop(dentry);
 525         return rc;
 526 }
 527
 528 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 529 {
 530         int rc;
 531         struct dentry *lower_dentry;
 532         struct dentry *lower_dir_dentry;
 533
 534         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 535         lower_dir_dentry = lock_parent(lower_dentry);
 536         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 537         if (rc || d_really_is_negative(lower_dentry))
 538                 goto out;
 539         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 540         if (rc)
 541                 goto out;
 542         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 543         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 544         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 545 out:
 546         unlock_dir(lower_dir_dentry);
 547         if (d_really_is_negative(dentry))
 548                 d_drop(dentry);
 549         return rc;
 550 }
 551
 552 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 553 {
 554         struct dentry *lower_dentry;
 555         struct dentry *lower_dir_dentry;
 556         int rc;
 557
 558         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 559         dget(dentry);
 560         lower_dir_dentry = lock_parent(lower_dentry);
 561         dget(lower_dentry);
 562         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 563         dput(lower_dentry);
 564         if (!rc && d_really_is_positive(dentry))
 565                 clear_nlink(d_inode(dentry));
 566         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 567         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 568         unlock_dir(lower_dir_dentry);
 569         if (!rc)
 570                 d_drop(dentry);
 571         dput(dentry);
 572         return rc;
 573 }
 574
 575 static int
 576 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 577 {
 578         int rc;
 579         struct dentry *lower_dentry;
 580         struct dentry *lower_dir_dentry;
 581
 582         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 583         lower_dir_dentry = lock_parent(lower_dentry);
 584         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 585         if (rc || d_really_is_negative(lower_dentry))
 586                 goto out;
 587         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 588         if (rc)
 589                 goto out;
 590         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 591         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 592 out:
 593         unlock_dir(lower_dir_dentry);
 594         if (d_really_is_negative(dentry))
 595                 d_drop(dentry);
 596         return rc;
 597 }
 598
 599 static int
 600 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 601                 struct inode *new_dir, struct dentry *new_dentry)
 602 {
 603         int rc;
 604         struct dentry *lower_old_dentry;
 605         struct dentry *lower_new_dentry;
 606         struct dentry *lower_old_dir_dentry;
 607         struct dentry *lower_new_dir_dentry;
 608         struct dentry *trap = NULL;
 609         struct inode *target_inode;
 610
 611         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 612         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 613         dget(lower_old_dentry);
 614         dget(lower_new_dentry);
 615         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 616         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 617         target_inode = d_inode(new_dentry);
 618         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 619         /* source should not be ancestor of target */
 620         if (trap == lower_old_dentry) {
 621                 rc = -EINVAL;
 622                 goto out_lock;
 623         }
 624         /* target should not be ancestor of source */
 625         if (trap == lower_new_dentry) {
 626                 rc = -ENOTEMPTY;
 627                 goto out_lock;
 628         }
 629         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 630                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 631                         NULL, 0);
 632         if (rc)
 633                 goto out_lock;
 634         if (target_inode)
 635                 fsstack_copy_attr_all(target_inode,
 636                                       ecryptfs_inode_to_lower(target_inode));
 637         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 638         if (new_dir != old_dir)
 639                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 640 out_lock:
 641         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 642         dput(lower_new_dir_dentry);
 643         dput(lower_old_dir_dentry);
 644         dput(lower_new_dentry);
 645         dput(lower_old_dentry);
 646         return rc;
 647 }
 648
 649 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 650 {
 651         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 652         char *lower_buf;
 653         char *buf;
 654         mm_segment_t old_fs;
 655         int rc;
 656
 657         lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
 658         if (!lower_buf)
 659                 return ERR_PTR(-ENOMEM);
 660         old_fs = get_fs();
 661         set_fs(get_ds());
 662         rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
 663                                                    (char __user *)lower_buf,
 664                                                    PATH_MAX);
 665         set_fs(old_fs);
 666         if (rc < 0)
 667                 goto out;
 668         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 669                                                   lower_buf, rc);
 670 out:
 671         kfree(lower_buf);
 672         return rc ? ERR_PTR(rc) : buf;
 673 }
 674
 675 static const char *ecryptfs_get_link(struct dentry *dentry,
 676                                      struct inode *inode,
 677                                      struct delayed_call *done)
 678 {
 679         size_t len;
 680         char *buf;
 681
 682         if (!dentry)
 683                 return ERR_PTR(-ECHILD);
 684
 685         buf = ecryptfs_readlink_lower(dentry, &len);
 686         if (IS_ERR(buf))
 687                 return buf;
 688         fsstack_copy_attr_atime(d_inode(dentry),
 689                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 690         buf[len] = '\0';
 691         set_delayed_call(done, kfree_link, buf);
 692         return buf;
 693 }
 694
 695 /**
 696  * upper_size_to_lower_size
 697  * @crypt_stat: Crypt_stat associated with file
 698  * @upper_size: Size of the upper file
 699  *
 700  * Calculate the required size of the lower file based on the
 701  * specified size of the upper file. This calculation is based on the
 702  * number of headers in the underlying file and the extent size.
 703  *
 704  * Returns Calculated size of the lower file.
 705  */
 706 static loff_t
 707 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 708                          loff_t upper_size)
 709 {
 710         loff_t lower_size;
 711
 712         lower_size = ecryptfs_lower_header_size(crypt_stat);
 713         if (upper_size != 0) {
 714                 loff_t num_extents;
 715
 716                 num_extents = upper_size >> crypt_stat->extent_shift;
 717                 if (upper_size & ~crypt_stat->extent_mask)
 718                         num_extents++;
 719                 lower_size += (num_extents * crypt_stat->extent_size);
 720         }
 721         return lower_size;
 722 }
 723
 724 /**
 725  * truncate_upper
 726  * @dentry: The ecryptfs layer dentry
 727  * @ia: Address of the ecryptfs inode's attributes
 728  * @lower_ia: Address of the lower inode's attributes
 729  *
 730  * Function to handle truncations modifying the size of the file. Note
 731  * that the file sizes are interpolated. When expanding, we are simply
 732  * writing strings of 0's out. When truncating, we truncate the upper
 733  * inode and update the lower_ia according to the page index
 734  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 735  * the caller must use lower_ia in a call to notify_change() to perform
 736  * the truncation of the lower inode.
 737  *
 738  * Returns zero on success; non-zero otherwise
 739  */
 740 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 741                           struct iattr *lower_ia)
 742 {
 743         int rc = 0;
 744         struct inode *inode = d_inode(dentry);
 745         struct ecryptfs_crypt_stat *crypt_stat;
 746         loff_t i_size = i_size_read(inode);
 747         loff_t lower_size_before_truncate;
 748         loff_t lower_size_after_truncate;
 749
 750         if (unlikely((ia->ia_size == i_size))) {
 751                 lower_ia->ia_valid &= ~ATTR_SIZE;
 752                 return 0;
 753         }
 754         rc = ecryptfs_get_lower_file(dentry, inode);
 755         if (rc)
 756                 return rc;
 757         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 758         /* Switch on growing or shrinking file */
 759         if (ia->ia_size > i_size) {
 760                 char zero[] = { 0x00 };
 761
 762                 lower_ia->ia_valid &= ~ATTR_SIZE;
 763                 /* Write a single 0 at the last position of the file;
 764                  * this triggers code that will fill in 0's throughout
 765                  * the intermediate portion of the previous end of the
 766                  * file and the new and of the file */
 767                 rc = ecryptfs_write(inode, zero,
 768                                     (ia->ia_size - 1), 1);
 769         } else { /* ia->ia_size < i_size_read(inode) */
 770                 /* We're chopping off all the pages down to the page
 771                  * in which ia->ia_size is located. Fill in the end of
 772                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
 773                  * PAGE_CACHE_SIZE with zeros. */
 774                 size_t num_zeros = (PAGE_CACHE_SIZE
 775                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
 776
 777                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 778                         truncate_setsize(inode, ia->ia_size);
 779                         lower_ia->ia_size = ia->ia_size;
 780                         lower_ia->ia_valid |= ATTR_SIZE;
 781                         goto out;
 782                 }
 783                 if (num_zeros) {
 784                         char *zeros_virt;
 785
 786                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 787                         if (!zeros_virt) {
 788                                 rc = -ENOMEM;
 789                                 goto out;
 790                         }
 791                         rc = ecryptfs_write(inode, zeros_virt,
 792                                             ia->ia_size, num_zeros);
 793                         kfree(zeros_virt);
 794                         if (rc) {
 795                                 printk(KERN_ERR "Error attempting to zero out "
 796                                        "the remainder of the end page on "
 797                                        "reducing truncate; rc = [%d]\n", rc);
 798                                 goto out;
 799                         }
 800                 }
 801                 truncate_setsize(inode, ia->ia_size);
 802                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 803                 if (rc) {
 804                         printk(KERN_ERR "Problem with "
 805                                "ecryptfs_write_inode_size_to_metadata; "
 806                                "rc = [%d]\n", rc);
 807                         goto out;
 808                 }
 809                 /* We are reducing the size of the ecryptfs file, and need to
 810                  * know if we need to reduce the size of the lower file. */
 811                 lower_size_before_truncate =
 812                     upper_size_to_lower_size(crypt_stat, i_size);
 813                 lower_size_after_truncate =
 814                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 815                 if (lower_size_after_truncate < lower_size_before_truncate) {
 816                         lower_ia->ia_size = lower_size_after_truncate;
 817                         lower_ia->ia_valid |= ATTR_SIZE;
 818                 } else
 819                         lower_ia->ia_valid &= ~ATTR_SIZE;
 820         }
 821 out:
 822         ecryptfs_put_lower_file(inode);
 823         return rc;
 824 }
 825
 826 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 827 {
 828         struct ecryptfs_crypt_stat *crypt_stat;
 829         loff_t lower_oldsize, lower_newsize;
 830
 831         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 832         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 833                                                  i_size_read(inode));
 834         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 835         if (lower_newsize > lower_oldsize) {
 836                 /*
 837                  * The eCryptfs inode and the new *lower* size are mixed here
 838                  * because we may not have the lower i_mutex held and/or it may
 839                  * not be appropriate to call inode_newsize_ok() with inodes
 840                  * from other filesystems.
 841                  */
 842                 return inode_newsize_ok(inode, lower_newsize);
 843         }
 844
 845         return 0;
 846 }
 847
 848 /**
 849  * ecryptfs_truncate
 850  * @dentry: The ecryptfs layer dentry
 851  * @new_length: The length to expand the file to
 852  *
 853  * Simple function that handles the truncation of an eCryptfs inode and
 854  * its corresponding lower inode.
 855  *
 856  * Returns zero on success; non-zero otherwise
 857  */
 858 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 859 {
 860         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 861         struct iattr lower_ia = { .ia_valid = 0 };
 862         int rc;
 863
 864         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 865         if (rc)
 866                 return rc;
 867
 868         rc = truncate_upper(dentry, &ia, &lower_ia);
 869         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 870                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 871
 872                 inode_lock(d_inode(lower_dentry));
 873                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 874                 inode_unlock(d_inode(lower_dentry));
 875         }
 876         return rc;
 877 }
 878
 879 static int
 880 ecryptfs_permission(struct inode *inode, int mask)
 881 {
 882         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 883 }
 884
 885 /**
 886  * ecryptfs_setattr
 887  * @dentry: dentry handle to the inode to modify
 888  * @ia: Structure with flags of what to change and values
 889  *
 890  * Updates the metadata of an inode. If the update is to the size
 891  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 892  * of both the ecryptfs inode and the lower inode.
 893  *
 894  * All other metadata changes will be passed right to the lower filesystem,
 895  * and we will just update our inode to look like the lower.
 896  */
 897 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 898 {
 899         int rc = 0;
 900         struct dentry *lower_dentry;
 901         struct iattr lower_ia;
 902         struct inode *inode;
 903         struct inode *lower_inode;
 904         struct ecryptfs_crypt_stat *crypt_stat;
 905
 906         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 907         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 908                 ecryptfs_init_crypt_stat(crypt_stat);
 909         inode = d_inode(dentry);
 910         lower_inode = ecryptfs_inode_to_lower(inode);
 911         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 912         mutex_lock(&crypt_stat->cs_mutex);
 913         if (d_is_dir(dentry))
 914                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 915         else if (d_is_reg(dentry)
 916                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 917                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 918                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 919
 920                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 921                         dentry->d_sb)->mount_crypt_stat;
 922                 rc = ecryptfs_get_lower_file(dentry, inode);
 923                 if (rc) {
 924                         mutex_unlock(&crypt_stat->cs_mutex);
 925                         goto out;
 926                 }
 927                 rc = ecryptfs_read_metadata(dentry);
 928                 ecryptfs_put_lower_file(inode);
 929                 if (rc) {
 930                         if (!(mount_crypt_stat->flags
 931                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 932                                 rc = -EIO;
 933                                 printk(KERN_WARNING "Either the lower file "
 934                                        "is not in a valid eCryptfs format, "
 935                                        "or the key could not be retrieved. "
 936                                        "Plaintext passthrough mode is not "
 937                                        "enabled; returning -EIO\n");
 938                                 mutex_unlock(&crypt_stat->cs_mutex);
 939                                 goto out;
 940                         }
 941                         rc = 0;
 942                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 943                                                | ECRYPTFS_ENCRYPTED);
 944                 }
 945         }
 946         mutex_unlock(&crypt_stat->cs_mutex);
 947
 948         rc = inode_change_ok(inode, ia);
 949         if (rc)
 950                 goto out;
 951         if (ia->ia_valid & ATTR_SIZE) {
 952                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 953                 if (rc)
 954                         goto out;
 955         }
 956
 957         memcpy(&lower_ia, ia, sizeof(lower_ia));
 958         if (ia->ia_valid & ATTR_FILE)
 959                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 960         if (ia->ia_valid & ATTR_SIZE) {
 961                 rc = truncate_upper(dentry, ia, &lower_ia);
 962                 if (rc < 0)
 963                         goto out;
 964         }
 965
 966         /*
 967          * mode change is for clearing setuid/setgid bits. Allow lower fs
 968          * to interpret this in its own way.
 969          */
 970         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 971                 lower_ia.ia_valid &= ~ATTR_MODE;
 972
 973         inode_lock(d_inode(lower_dentry));
 974         rc = notify_change(lower_dentry, &lower_ia, NULL);
 975         inode_unlock(d_inode(lower_dentry));
 976 out:
 977         fsstack_copy_attr_all(inode, lower_inode);
 978         return rc;
 979 }
 980
 981 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
 982                                  struct kstat *stat)
 983 {
 984         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 985         int rc = 0;
 986
 987         mount_crypt_stat = &ecryptfs_superblock_to_private(
 988                                                 dentry->d_sb)->mount_crypt_stat;
 989         generic_fillattr(d_inode(dentry), stat);
 990         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 991                 char *target;
 992                 size_t targetsiz;
 993
 994                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 995                 if (!IS_ERR(target)) {
 996                         kfree(target);
 997                         stat->size = targetsiz;
 998                 } else {
 999                         rc = PTR_ERR(target);
1000                 }
1001         }
1002         return rc;
1003 }
1004
1005 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1006                             struct kstat *stat)
1007 {
1008         struct kstat lower_stat;
1009         int rc;
1010
1011         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
1012         if (!rc) {
1013                 fsstack_copy_attr_all(d_inode(dentry),
1014                                       ecryptfs_inode_to_lower(d_inode(dentry)));
1015                 generic_fillattr(d_inode(dentry), stat);
1016                 stat->blocks = lower_stat.blocks;
1017         }
1018         return rc;
1019 }
1020
1021 int
1022 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1023                   size_t size, int flags)
1024 {
1025         int rc = 0;
1026         struct dentry *lower_dentry;
1027
1028         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1029         if (!d_inode(lower_dentry)->i_op->setxattr) {
1030                 rc = -EOPNOTSUPP;
1031                 goto out;
1032         }
1033
1034         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1035         if (!rc && d_really_is_positive(dentry))
1036                 fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry));
1037 out:
1038         return rc;
1039 }
1040
1041 ssize_t
1042 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1043                         void *value, size_t size)
1044 {
1045         int rc = 0;
1046
1047         if (!d_inode(lower_dentry)->i_op->getxattr) {
1048                 rc = -EOPNOTSUPP;
1049                 goto out;
1050         }
1051         inode_lock(d_inode(lower_dentry));
1052         rc = d_inode(lower_dentry)->i_op->getxattr(lower_dentry, name, value,
1053                                                    size);
1054         inode_unlock(d_inode(lower_dentry));
1055 out:
1056         return rc;
1057 }
1058
1059 static ssize_t
1060 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1061                   size_t size)
1062 {
1063         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1064                                        value, size);
1065 }
1066
1067 static ssize_t
1068 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1069 {
1070         int rc = 0;
1071         struct dentry *lower_dentry;
1072
1073         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1074         if (!d_inode(lower_dentry)->i_op->listxattr) {
1075                 rc = -EOPNOTSUPP;
1076                 goto out;
1077         }
1078         inode_lock(d_inode(lower_dentry));
1079         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1080         inode_unlock(d_inode(lower_dentry));
1081 out:
1082         return rc;
1083 }
1084
1085 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1086 {
1087         int rc = 0;
1088         struct dentry *lower_dentry;
1089
1090         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1091         if (!d_inode(lower_dentry)->i_op->removexattr) {
1092                 rc = -EOPNOTSUPP;
1093                 goto out;
1094         }
1095         inode_lock(d_inode(lower_dentry));
1096         rc = d_inode(lower_dentry)->i_op->removexattr(lower_dentry, name);
1097         inode_unlock(d_inode(lower_dentry));
1098 out:
1099         return rc;
1100 }
1101
1102 const struct inode_operations ecryptfs_symlink_iops = {
1103         .readlink = generic_readlink,
1104         .get_link = ecryptfs_get_link,
1105         .permission = ecryptfs_permission,
1106         .setattr = ecryptfs_setattr,
1107         .getattr = ecryptfs_getattr_link,
1108         .setxattr = ecryptfs_setxattr,
1109         .getxattr = ecryptfs_getxattr,
1110         .listxattr = ecryptfs_listxattr,
1111         .removexattr = ecryptfs_removexattr
1112 };
1113
1114 const struct inode_operations ecryptfs_dir_iops = {
1115         .create = ecryptfs_create,
1116         .lookup = ecryptfs_lookup,
1117         .link = ecryptfs_link,
1118         .unlink = ecryptfs_unlink,
1119         .symlink = ecryptfs_symlink,
1120         .mkdir = ecryptfs_mkdir,
1121         .rmdir = ecryptfs_rmdir,
1122         .mknod = ecryptfs_mknod,
1123         .rename = ecryptfs_rename,
1124         .permission = ecryptfs_permission,
1125         .setattr = ecryptfs_setattr,
1126         .setxattr = ecryptfs_setxattr,
1127         .getxattr = ecryptfs_getxattr,
1128         .listxattr = ecryptfs_listxattr,
1129         .removexattr = ecryptfs_removexattr
1130 };
1131
1132 const struct inode_operations ecryptfs_main_iops = {
1133         .permission = ecryptfs_permission,
1134         .setattr = ecryptfs_setattr,
1135         .getattr = ecryptfs_getattr,
1136         .setxattr = ecryptfs_setxattr,
1137         .getxattr = ecryptfs_getxattr,
1138         .listxattr = ecryptfs_listxattr,
1139         .removexattr = ecryptfs_removexattr
1140 };