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, 0);
 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 char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 654 {
 655         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 656         char *lower_buf;
 657         char *buf;
 658         mm_segment_t old_fs;
 659         int rc;
 660
 661         lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
 662         if (!lower_buf)
 663                 return ERR_PTR(-ENOMEM);
 664         old_fs = get_fs();
 665         set_fs(get_ds());
 666         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 667                                                    (char __user *)lower_buf,
 668                                                    PATH_MAX);
 669         set_fs(old_fs);
 670         if (rc < 0)
 671                 goto out;
 672         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 673                                                   lower_buf, rc);
 674 out:
 675         kfree(lower_buf);
 676         return rc ? ERR_PTR(rc) : buf;
 677 }
 678
 679 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 680 {
 681         size_t len;
 682         char *buf = ecryptfs_readlink_lower(dentry, &len);
 683         if (IS_ERR(buf))
 684                 goto out;
 685         fsstack_copy_attr_atime(dentry->d_inode,
 686                                 ecryptfs_dentry_to_lower(dentry)->d_inode);
 687         buf[len] = '\0';
 688 out:
 689         nd_set_link(nd, buf);
 690         return NULL;
 691 }
 692
 693 /**
 694  * upper_size_to_lower_size
 695  * @crypt_stat: Crypt_stat associated with file
 696  * @upper_size: Size of the upper file
 697  *
 698  * Calculate the required size of the lower file based on the
 699  * specified size of the upper file. This calculation is based on the
 700  * number of headers in the underlying file and the extent size.
 701  *
 702  * Returns Calculated size of the lower file.
 703  */
 704 static loff_t
 705 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 706                          loff_t upper_size)
 707 {
 708         loff_t lower_size;
 709
 710         lower_size = ecryptfs_lower_header_size(crypt_stat);
 711         if (upper_size != 0) {
 712                 loff_t num_extents;
 713
 714                 num_extents = upper_size >> crypt_stat->extent_shift;
 715                 if (upper_size & ~crypt_stat->extent_mask)
 716                         num_extents++;
 717                 lower_size += (num_extents * crypt_stat->extent_size);
 718         }
 719         return lower_size;
 720 }
 721
 722 /**
 723  * truncate_upper
 724  * @dentry: The ecryptfs layer dentry
 725  * @ia: Address of the ecryptfs inode's attributes
 726  * @lower_ia: Address of the lower inode's attributes
 727  *
 728  * Function to handle truncations modifying the size of the file. Note
 729  * that the file sizes are interpolated. When expanding, we are simply
 730  * writing strings of 0's out. When truncating, we truncate the upper
 731  * inode and update the lower_ia according to the page index
 732  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 733  * the caller must use lower_ia in a call to notify_change() to perform
 734  * the truncation of the lower inode.
 735  *
 736  * Returns zero on success; non-zero otherwise
 737  */
 738 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 739                           struct iattr *lower_ia)
 740 {
 741         int rc = 0;
 742         struct inode *inode = dentry->d_inode;
 743         struct ecryptfs_crypt_stat *crypt_stat;
 744         loff_t i_size = i_size_read(inode);
 745         loff_t lower_size_before_truncate;
 746         loff_t lower_size_after_truncate;
 747
 748         if (unlikely((ia->ia_size == i_size))) {
 749                 lower_ia->ia_valid &= ~ATTR_SIZE;
 750                 return 0;
 751         }
 752         rc = ecryptfs_get_lower_file(dentry, inode);
 753         if (rc)
 754                 return rc;
 755         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 756         /* Switch on growing or shrinking file */
 757         if (ia->ia_size > i_size) {
 758                 char zero[] = { 0x00 };
 759
 760                 lower_ia->ia_valid &= ~ATTR_SIZE;
 761                 /* Write a single 0 at the last position of the file;
 762                  * this triggers code that will fill in 0's throughout
 763                  * the intermediate portion of the previous end of the
 764                  * file and the new and of the file */
 765                 rc = ecryptfs_write(inode, zero,
 766                                     (ia->ia_size - 1), 1);
 767         } else { /* ia->ia_size < i_size_read(inode) */
 768                 /* We're chopping off all the pages down to the page
 769                  * in which ia->ia_size is located. Fill in the end of
 770                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
 771                  * PAGE_CACHE_SIZE with zeros. */
 772                 size_t num_zeros = (PAGE_CACHE_SIZE
 773                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
 774
 775                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 776                         truncate_setsize(inode, ia->ia_size);
 777                         lower_ia->ia_size = ia->ia_size;
 778                         lower_ia->ia_valid |= ATTR_SIZE;
 779                         goto out;
 780                 }
 781                 if (num_zeros) {
 782                         char *zeros_virt;
 783
 784                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 785                         if (!zeros_virt) {
 786                                 rc = -ENOMEM;
 787                                 goto out;
 788                         }
 789                         rc = ecryptfs_write(inode, zeros_virt,
 790                                             ia->ia_size, num_zeros);
 791                         kfree(zeros_virt);
 792                         if (rc) {
 793                                 printk(KERN_ERR "Error attempting to zero out "
 794                                        "the remainder of the end page on "
 795                                        "reducing truncate; rc = [%d]\n", rc);
 796                                 goto out;
 797                         }
 798                 }
 799                 truncate_setsize(inode, ia->ia_size);
 800                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 801                 if (rc) {
 802                         printk(KERN_ERR "Problem with "
 803                                "ecryptfs_write_inode_size_to_metadata; "
 804                                "rc = [%d]\n", rc);
 805                         goto out;
 806                 }
 807                 /* We are reducing the size of the ecryptfs file, and need to
 808                  * know if we need to reduce the size of the lower file. */
 809                 lower_size_before_truncate =
 810                     upper_size_to_lower_size(crypt_stat, i_size);
 811                 lower_size_after_truncate =
 812                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 813                 if (lower_size_after_truncate < lower_size_before_truncate) {
 814                         lower_ia->ia_size = lower_size_after_truncate;
 815                         lower_ia->ia_valid |= ATTR_SIZE;
 816                 } else
 817                         lower_ia->ia_valid &= ~ATTR_SIZE;
 818         }
 819 out:
 820         ecryptfs_put_lower_file(inode);
 821         return rc;
 822 }
 823
 824 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 825 {
 826         struct ecryptfs_crypt_stat *crypt_stat;
 827         loff_t lower_oldsize, lower_newsize;
 828
 829         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 830         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 831                                                  i_size_read(inode));
 832         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 833         if (lower_newsize > lower_oldsize) {
 834                 /*
 835                  * The eCryptfs inode and the new *lower* size are mixed here
 836                  * because we may not have the lower i_mutex held and/or it may
 837                  * not be appropriate to call inode_newsize_ok() with inodes
 838                  * from other filesystems.
 839                  */
 840                 return inode_newsize_ok(inode, lower_newsize);
 841         }
 842
 843         return 0;
 844 }
 845
 846 /**
 847  * ecryptfs_truncate
 848  * @dentry: The ecryptfs layer dentry
 849  * @new_length: The length to expand the file to
 850  *
 851  * Simple function that handles the truncation of an eCryptfs inode and
 852  * its corresponding lower inode.
 853  *
 854  * Returns zero on success; non-zero otherwise
 855  */
 856 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 857 {
 858         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 859         struct iattr lower_ia = { .ia_valid = 0 };
 860         int rc;
 861
 862         rc = ecryptfs_inode_newsize_ok(dentry->d_inode, new_length);
 863         if (rc)
 864                 return rc;
 865
 866         rc = truncate_upper(dentry, &ia, &lower_ia);
 867         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 868                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 869
 870                 mutex_lock(&lower_dentry->d_inode->i_mutex);
 871                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 872                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
 873         }
 874         return rc;
 875 }
 876
 877 static int
 878 ecryptfs_permission(struct inode *inode, int mask)
 879 {
 880         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 881 }
 882
 883 /**
 884  * ecryptfs_setattr
 885  * @dentry: dentry handle to the inode to modify
 886  * @ia: Structure with flags of what to change and values
 887  *
 888  * Updates the metadata of an inode. If the update is to the size
 889  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 890  * of both the ecryptfs inode and the lower inode.
 891  *
 892  * All other metadata changes will be passed right to the lower filesystem,
 893  * and we will just update our inode to look like the lower.
 894  */
 895 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 896 {
 897         int rc = 0;
 898         struct dentry *lower_dentry;
 899         struct iattr lower_ia;
 900         struct inode *inode;
 901         struct inode *lower_inode;
 902         struct ecryptfs_crypt_stat *crypt_stat;
 903
 904         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 905         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 906                 ecryptfs_init_crypt_stat(crypt_stat);
 907         inode = dentry->d_inode;
 908         lower_inode = ecryptfs_inode_to_lower(inode);
 909         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 910         mutex_lock(&crypt_stat->cs_mutex);
 911         if (S_ISDIR(dentry->d_inode->i_mode))
 912                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 913         else if (S_ISREG(dentry->d_inode->i_mode)
 914                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 915                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 916                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 917
 918                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 919                         dentry->d_sb)->mount_crypt_stat;
 920                 rc = ecryptfs_get_lower_file(dentry, inode);
 921                 if (rc) {
 922                         mutex_unlock(&crypt_stat->cs_mutex);
 923                         goto out;
 924                 }
 925                 rc = ecryptfs_read_metadata(dentry);
 926                 ecryptfs_put_lower_file(inode);
 927                 if (rc) {
 928                         if (!(mount_crypt_stat->flags
 929                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 930                                 rc = -EIO;
 931                                 printk(KERN_WARNING "Either the lower file "
 932                                        "is not in a valid eCryptfs format, "
 933                                        "or the key could not be retrieved. "
 934                                        "Plaintext passthrough mode is not "
 935                                        "enabled; returning -EIO\n");
 936                                 mutex_unlock(&crypt_stat->cs_mutex);
 937                                 goto out;
 938                         }
 939                         rc = 0;
 940                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 941                                                | ECRYPTFS_ENCRYPTED);
 942                 }
 943         }
 944         mutex_unlock(&crypt_stat->cs_mutex);
 945
 946         rc = inode_change_ok(inode, ia);
 947         if (rc)
 948                 goto out;
 949         if (ia->ia_valid & ATTR_SIZE) {
 950                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 951                 if (rc)
 952                         goto out;
 953         }
 954
 955         memcpy(&lower_ia, ia, sizeof(lower_ia));
 956         if (ia->ia_valid & ATTR_FILE)
 957                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 958         if (ia->ia_valid & ATTR_SIZE) {
 959                 rc = truncate_upper(dentry, ia, &lower_ia);
 960                 if (rc < 0)
 961                         goto out;
 962         }
 963
 964         /*
 965          * mode change is for clearing setuid/setgid bits. Allow lower fs
 966          * to interpret this in its own way.
 967          */
 968         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 969                 lower_ia.ia_valid &= ~ATTR_MODE;
 970
 971         mutex_lock(&lower_dentry->d_inode->i_mutex);
 972         rc = notify_change(lower_dentry, &lower_ia, NULL);
 973         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 974 out:
 975         fsstack_copy_attr_all(inode, lower_inode);
 976         return rc;
 977 }
 978
 979 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
 980                                  struct kstat *stat)
 981 {
 982         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 983         int rc = 0;
 984
 985         mount_crypt_stat = &ecryptfs_superblock_to_private(
 986                                                 dentry->d_sb)->mount_crypt_stat;
 987         generic_fillattr(dentry->d_inode, stat);
 988         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 989                 char *target;
 990                 size_t targetsiz;
 991
 992                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 993                 if (!IS_ERR(target)) {
 994                         kfree(target);
 995                         stat->size = targetsiz;
 996                 } else {
 997                         rc = PTR_ERR(target);
 998                 }
 999         }
1000         return rc;
1001 }
1002
1003 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1004                             struct kstat *stat)
1005 {
1006         struct kstat lower_stat;
1007         int rc;
1008
1009         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
1010         if (!rc) {
1011                 fsstack_copy_attr_all(dentry->d_inode,
1012                                       ecryptfs_inode_to_lower(dentry->d_inode));
1013                 generic_fillattr(dentry->d_inode, stat);
1014                 stat->blocks = lower_stat.blocks;
1015         }
1016         return rc;
1017 }
1018
1019 int
1020 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1021                   size_t size, int flags)
1022 {
1023         int rc = 0;
1024         struct dentry *lower_dentry;
1025
1026         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1027         if (!lower_dentry->d_inode->i_op->setxattr) {
1028                 rc = -EOPNOTSUPP;
1029                 goto out;
1030         }
1031
1032         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1033         if (!rc && dentry->d_inode)
1034                 fsstack_copy_attr_all(dentry->d_inode, lower_dentry->d_inode);
1035 out:
1036         return rc;
1037 }
1038
1039 ssize_t
1040 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1041                         void *value, size_t size)
1042 {
1043         int rc = 0;
1044
1045         if (!lower_dentry->d_inode->i_op->getxattr) {
1046                 rc = -EOPNOTSUPP;
1047                 goto out;
1048         }
1049         mutex_lock(&lower_dentry->d_inode->i_mutex);
1050         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1051                                                    size);
1052         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1053 out:
1054         return rc;
1055 }
1056
1057 static ssize_t
1058 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1059                   size_t size)
1060 {
1061         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1062                                        value, size);
1063 }
1064
1065 static ssize_t
1066 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1067 {
1068         int rc = 0;
1069         struct dentry *lower_dentry;
1070
1071         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1072         if (!lower_dentry->d_inode->i_op->listxattr) {
1073                 rc = -EOPNOTSUPP;
1074                 goto out;
1075         }
1076         mutex_lock(&lower_dentry->d_inode->i_mutex);
1077         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1078         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1079 out:
1080         return rc;
1081 }
1082
1083 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1084 {
1085         int rc = 0;
1086         struct dentry *lower_dentry;
1087
1088         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1089         if (!lower_dentry->d_inode->i_op->removexattr) {
1090                 rc = -EOPNOTSUPP;
1091                 goto out;
1092         }
1093         mutex_lock(&lower_dentry->d_inode->i_mutex);
1094         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1095         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1096 out:
1097         return rc;
1098 }
1099
1100 const struct inode_operations ecryptfs_symlink_iops = {
1101         .readlink = generic_readlink,
1102         .follow_link = ecryptfs_follow_link,
1103         .put_link = kfree_put_link,
1104         .permission = ecryptfs_permission,
1105         .setattr = ecryptfs_setattr,
1106         .getattr = ecryptfs_getattr_link,
1107         .setxattr = ecryptfs_setxattr,
1108         .getxattr = ecryptfs_getxattr,
1109         .listxattr = ecryptfs_listxattr,
1110         .removexattr = ecryptfs_removexattr
1111 };
1112
1113 const struct inode_operations ecryptfs_dir_iops = {
1114         .create = ecryptfs_create,
1115         .lookup = ecryptfs_lookup,
1116         .link = ecryptfs_link,
1117         .unlink = ecryptfs_unlink,
1118         .symlink = ecryptfs_symlink,
1119         .mkdir = ecryptfs_mkdir,
1120         .rmdir = ecryptfs_rmdir,
1121         .mknod = ecryptfs_mknod,
1122         .rename = ecryptfs_rename,
1123         .permission = ecryptfs_permission,
1124         .setattr = ecryptfs_setattr,
1125         .setxattr = ecryptfs_setxattr,
1126         .getxattr = ecryptfs_getxattr,
1127         .listxattr = ecryptfs_listxattr,
1128         .removexattr = ecryptfs_removexattr
1129 };
1130
1131 const struct inode_operations ecryptfs_main_iops = {
1132         .permission = ecryptfs_permission,
1133         .setattr = ecryptfs_setattr,
1134         .getattr = ecryptfs_getattr,
1135         .setxattr = ecryptfs_setxattr,
1136         .getxattr = ecryptfs_getxattr,
1137         .listxattr = ecryptfs_listxattr,
1138         .removexattr = ecryptfs_removexattr
1139 };