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