fs/ecryptfs/inode.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2004 Erez Zadok
   5  * Copyright (C) 2001-2004 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #include <linux/file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/dcache.h>
  30 #include <linux/namei.h>
  31 #include <linux/mount.h>
  32 #include <linux/fs_stack.h>
  33 #include <linux/slab.h>
  34 #include <linux/xattr.h>
  35 #include <asm/unaligned.h>
  36 #include "ecryptfs_kernel.h"
  37
  38 static struct dentry *lock_parent(struct dentry *dentry)
  39 {
  40         struct dentry *dir;
  41
  42         dir = dget_parent(dentry);
  43         inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
  44         return dir;
  45 }
  46
  47 static void unlock_dir(struct dentry *dir)
  48 {
  49         inode_unlock(d_inode(dir));
  50         dput(dir);
  51 }
  52
  53 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
  54 {
  55         return ecryptfs_inode_to_lower(inode) == lower_inode;
  56 }
  57
  58 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
  59 {
  60         struct inode *lower_inode = opaque;
  61
  62         ecryptfs_set_inode_lower(inode, lower_inode);
  63         fsstack_copy_attr_all(inode, lower_inode);
  64         /* i_size will be overwritten for encrypted regular files */
  65         fsstack_copy_inode_size(inode, lower_inode);
  66         inode->i_ino = lower_inode->i_ino;
  67         inode->i_version++;
  68         inode->i_mapping->a_ops = &ecryptfs_aops;
  69
  70         if (S_ISLNK(inode->i_mode))
  71                 inode->i_op = &ecryptfs_symlink_iops;
  72         else if (S_ISDIR(inode->i_mode))
  73                 inode->i_op = &ecryptfs_dir_iops;
  74         else
  75                 inode->i_op = &ecryptfs_main_iops;
  76
  77         if (S_ISDIR(inode->i_mode))
  78                 inode->i_fop = &ecryptfs_dir_fops;
  79         else if (special_file(inode->i_mode))
  80                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
  81         else
  82                 inode->i_fop = &ecryptfs_main_fops;
  83
  84         return 0;
  85 }
  86
  87 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  88                                           struct super_block *sb)
  89 {
  90         struct inode *inode;
  91
  92         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  93                 return ERR_PTR(-EXDEV);
  94         if (!igrab(lower_inode))
  95                 return ERR_PTR(-ESTALE);
  96         inode = iget5_locked(sb, (unsigned long)lower_inode,
  97                              ecryptfs_inode_test, ecryptfs_inode_set,
  98                              lower_inode);
  99         if (!inode) {
 100                 iput(lower_inode);
 101                 return ERR_PTR(-EACCES);
 102         }
 103         if (!(inode->i_state & I_NEW))
 104                 iput(lower_inode);
 105
 106         return inode;
 107 }
 108
 109 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 110                                  struct super_block *sb)
 111 {
 112         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 113
 114         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 115                 unlock_new_inode(inode);
 116
 117         return inode;
 118 }
 119
 120 /**
 121  * ecryptfs_interpose
 122  * @lower_dentry: Existing dentry in the lower filesystem
 123  * @dentry: ecryptfs' dentry
 124  * @sb: ecryptfs's super_block
 125  *
 126  * Interposes upper and lower dentries.
 127  *
 128  * Returns zero on success; non-zero otherwise
 129  */
 130 static int ecryptfs_interpose(struct dentry *lower_dentry,
 131                               struct dentry *dentry, struct super_block *sb)
 132 {
 133         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 134
 135         if (IS_ERR(inode))
 136                 return PTR_ERR(inode);
 137         d_instantiate(dentry, inode);
 138
 139         return 0;
 140 }
 141
 142 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 143                               struct inode *inode)
 144 {
 145         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 146         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 147         struct dentry *lower_dir_dentry;
 148         int rc;
 149
 150         dget(lower_dentry);
 151         lower_dir_dentry = lock_parent(lower_dentry);
 152         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 153         if (rc) {
 154                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 155                 goto out_unlock;
 156         }
 157         fsstack_copy_attr_times(dir, lower_dir_inode);
 158         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 159         inode->i_ctime = dir->i_ctime;
 160         d_drop(dentry);
 161 out_unlock:
 162         unlock_dir(lower_dir_dentry);
 163         dput(lower_dentry);
 164         return rc;
 165 }
 166
 167 /**
 168  * ecryptfs_do_create
 169  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 170  * @ecryptfs_dentry: New file's dentry in ecryptfs
 171  * @mode: The mode of the new file
 172  *
 173  * Creates the underlying file and the eCryptfs inode which will link to
 174  * it. It will also update the eCryptfs directory inode to mimic the
 175  * stat of the lower directory inode.
 176  *
 177  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 178  */
 179 static struct inode *
 180 ecryptfs_do_create(struct inode *directory_inode,
 181                    struct dentry *ecryptfs_dentry, umode_t mode)
 182 {
 183         int rc;
 184         struct dentry *lower_dentry;
 185         struct dentry *lower_dir_dentry;
 186         struct inode *inode;
 187
 188         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 189         lower_dir_dentry = lock_parent(lower_dentry);
 190         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 191         if (rc) {
 192                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 193                        "rc = [%d]\n", __func__, rc);
 194                 inode = ERR_PTR(rc);
 195                 goto out_lock;
 196         }
 197         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 198                                      directory_inode->i_sb);
 199         if (IS_ERR(inode)) {
 200                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 201                 goto out_lock;
 202         }
 203         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 204         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 205 out_lock:
 206         unlock_dir(lower_dir_dentry);
 207         return inode;
 208 }
 209
 210 /**
 211  * ecryptfs_initialize_file
 212  *
 213  * Cause the file to be changed from a basic empty file to an ecryptfs
 214  * file with a header and first data page.
 215  *
 216  * Returns zero on success
 217  */
 218 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 219                              struct inode *ecryptfs_inode)
 220 {
 221         struct ecryptfs_crypt_stat *crypt_stat =
 222                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 223         int rc = 0;
 224
 225         if (S_ISDIR(ecryptfs_inode->i_mode)) {
 226                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 227                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 228                 goto out;
 229         }
 230         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 231         rc = ecryptfs_new_file_context(ecryptfs_inode);
 232         if (rc) {
 233                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 234                                 "context; rc = [%d]\n", rc);
 235                 goto out;
 236         }
 237         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 238         if (rc) {
 239                 printk(KERN_ERR "%s: Error attempting to initialize "
 240                         "the lower file for the dentry with name "
 241                         "[%pd]; rc = [%d]\n", __func__,
 242                         ecryptfs_dentry, rc);
 243                 goto out;
 244         }
 245         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 246         if (rc)
 247                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 248         ecryptfs_put_lower_file(ecryptfs_inode);
 249 out:
 250         return rc;
 251 }
 252
 253 /**
 254  * ecryptfs_create
 255  * @dir: The inode of the directory in which to create the file.
 256  * @dentry: The eCryptfs dentry
 257  * @mode: The mode of the new file.
 258  *
 259  * Creates a new file.
 260  *
 261  * Returns zero on success; non-zero on error condition
 262  */
 263 static int
 264 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 265                 umode_t mode, bool excl)
 266 {
 267         struct inode *ecryptfs_inode;
 268         int rc;
 269
 270         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 271                                             mode);
 272         if (IS_ERR(ecryptfs_inode)) {
 273                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 274                                 "lower filesystem\n");
 275                 rc = PTR_ERR(ecryptfs_inode);
 276                 goto out;
 277         }
 278         /* At this point, a file exists on "disk"; we need to make sure
 279          * that this on disk file is prepared to be an ecryptfs file */
 280         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 281         if (rc) {
 282                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 283                                    ecryptfs_inode);
 284                 iget_failed(ecryptfs_inode);
 285                 goto out;
 286         }
 287         unlock_new_inode(ecryptfs_inode);
 288         d_instantiate(ecryptfs_dentry, ecryptfs_inode);
 289 out:
 290         return rc;
 291 }
 292
 293 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 294 {
 295         struct ecryptfs_crypt_stat *crypt_stat;
 296         int rc;
 297
 298         rc = ecryptfs_get_lower_file(dentry, inode);
 299         if (rc) {
 300                 printk(KERN_ERR "%s: Error attempting to initialize "
 301                         "the lower file for the dentry with name "
 302                         "[%pd]; rc = [%d]\n", __func__,
 303                         dentry, rc);
 304                 return rc;
 305         }
 306
 307         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 308         /* TODO: lock for crypt_stat comparison */
 309         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 310                 ecryptfs_set_default_sizes(crypt_stat);
 311
 312         rc = ecryptfs_read_and_validate_header_region(inode);
 313         ecryptfs_put_lower_file(inode);
 314         if (rc) {
 315                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
 316                 if (!rc)
 317                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 318         }
 319
 320         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
 321         return 0;
 322 }
 323
 324 /**
 325  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 326  */
 327 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
 328                                      struct dentry *lower_dentry)
 329 {
 330         struct inode *inode, *lower_inode = d_inode(lower_dentry);
 331         struct ecryptfs_dentry_info *dentry_info;
 332         struct vfsmount *lower_mnt;
 333         int rc = 0;
 334
 335         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 336         if (!dentry_info) {
 337                 printk(KERN_ERR "%s: Out of memory whilst attempting "
 338                        "to allocate ecryptfs_dentry_info struct\n",
 339                         __func__);
 340                 dput(lower_dentry);
 341                 return ERR_PTR(-ENOMEM);
 342         }
 343
 344         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 345         fsstack_copy_attr_atime(d_inode(dentry->d_parent),
 346                                 d_inode(lower_dentry->d_parent));
 347         BUG_ON(!d_count(lower_dentry));
 348
 349         ecryptfs_set_dentry_private(dentry, dentry_info);
 350         dentry_info->lower_path.mnt = lower_mnt;
 351         dentry_info->lower_path.dentry = lower_dentry;
 352
 353         if (d_really_is_negative(lower_dentry)) {
 354                 /* We want to add because we couldn't find in lower */
 355                 d_add(dentry, NULL);
 356                 return NULL;
 357         }
 358         inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
 359         if (IS_ERR(inode)) {
 360                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 361                        __func__, PTR_ERR(inode));
 362                 return ERR_CAST(inode);
 363         }
 364         if (S_ISREG(inode->i_mode)) {
 365                 rc = ecryptfs_i_size_read(dentry, inode);
 366                 if (rc) {
 367                         make_bad_inode(inode);
 368                         return ERR_PTR(rc);
 369                 }
 370         }
 371
 372         if (inode->i_state & I_NEW)
 373                 unlock_new_inode(inode);
 374         return d_splice_alias(inode, dentry);
 375 }
 376
 377 /**
 378  * ecryptfs_lookup
 379  * @ecryptfs_dir_inode: The eCryptfs directory inode
 380  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 381  * @flags: lookup flags
 382  *
 383  * Find a file on disk. If the file does not exist, then we'll add it to the
 384  * dentry cache and continue on to read it from the disk.
 385  */
 386 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 387                                       struct dentry *ecryptfs_dentry,
 388                                       unsigned int flags)
 389 {
 390         char *encrypted_and_encoded_name = NULL;
 391         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 392         struct dentry *lower_dir_dentry, *lower_dentry;
 393         const char *name = ecryptfs_dentry->d_name.name;
 394         size_t len = ecryptfs_dentry->d_name.len;
 395         struct dentry *res;
 396         int rc = 0;
 397
 398         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 399
 400         mount_crypt_stat = &ecryptfs_superblock_to_private(
 401                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 402         if (mount_crypt_stat
 403             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
 404                 rc = ecryptfs_encrypt_and_encode_filename(
 405                         &encrypted_and_encoded_name, &len,
 406                         mount_crypt_stat, name, len);
 407                 if (rc) {
 408                         printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 409                                "filename; rc = [%d]\n", __func__, rc);
 410                         return ERR_PTR(rc);
 411                 }
 412                 name = encrypted_and_encoded_name;
 413         }
 414
 415         lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
 416         if (IS_ERR(lower_dentry)) {
 417                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 418                                 "[%ld] on lower_dentry = [%s]\n", __func__,
 419                                 PTR_ERR(lower_dentry),
 420                                 name);
 421                 res = ERR_CAST(lower_dentry);
 422         } else {
 423                 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
 424         }
 425         kfree(encrypted_and_encoded_name);
 426         return res;
 427 }
 428
 429 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 430                          struct dentry *new_dentry)
 431 {
 432         struct dentry *lower_old_dentry;
 433         struct dentry *lower_new_dentry;
 434         struct dentry *lower_dir_dentry;
 435         u64 file_size_save;
 436         int rc;
 437
 438         file_size_save = i_size_read(d_inode(old_dentry));
 439         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 440         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 441         dget(lower_old_dentry);
 442         dget(lower_new_dentry);
 443         lower_dir_dentry = lock_parent(lower_new_dentry);
 444         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 445                       lower_new_dentry, NULL);
 446         if (rc || d_really_is_negative(lower_new_dentry))
 447                 goto out_lock;
 448         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 449         if (rc)
 450                 goto out_lock;
 451         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 452         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 453         set_nlink(d_inode(old_dentry),
 454                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 455         i_size_write(d_inode(new_dentry), file_size_save);
 456 out_lock:
 457         unlock_dir(lower_dir_dentry);
 458         dput(lower_new_dentry);
 459         dput(lower_old_dentry);
 460         return rc;
 461 }
 462
 463 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 464 {
 465         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 466 }
 467
 468 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 469                             const char *symname)
 470 {
 471         int rc;
 472         struct dentry *lower_dentry;
 473         struct dentry *lower_dir_dentry;
 474         char *encoded_symname;
 475         size_t encoded_symlen;
 476         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 477
 478         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 479         dget(lower_dentry);
 480         lower_dir_dentry = lock_parent(lower_dentry);
 481         mount_crypt_stat = &ecryptfs_superblock_to_private(
 482                 dir->i_sb)->mount_crypt_stat;
 483         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 484                                                   &encoded_symlen,
 485                                                   mount_crypt_stat, symname,
 486                                                   strlen(symname));
 487         if (rc)
 488                 goto out_lock;
 489         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 490                          encoded_symname);
 491         kfree(encoded_symname);
 492         if (rc || d_really_is_negative(lower_dentry))
 493                 goto out_lock;
 494         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 495         if (rc)
 496                 goto out_lock;
 497         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 498         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 499 out_lock:
 500         unlock_dir(lower_dir_dentry);
 501         dput(lower_dentry);
 502         if (d_really_is_negative(dentry))
 503                 d_drop(dentry);
 504         return rc;
 505 }
 506
 507 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 508 {
 509         int rc;
 510         struct dentry *lower_dentry;
 511         struct dentry *lower_dir_dentry;
 512
 513         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 514         lower_dir_dentry = lock_parent(lower_dentry);
 515         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 516         if (rc || d_really_is_negative(lower_dentry))
 517                 goto out;
 518         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 519         if (rc)
 520                 goto out;
 521         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 522         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 523         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 524 out:
 525         unlock_dir(lower_dir_dentry);
 526         if (d_really_is_negative(dentry))
 527                 d_drop(dentry);
 528         return rc;
 529 }
 530
 531 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 532 {
 533         struct dentry *lower_dentry;
 534         struct dentry *lower_dir_dentry;
 535         int rc;
 536
 537         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 538         dget(dentry);
 539         lower_dir_dentry = lock_parent(lower_dentry);
 540         dget(lower_dentry);
 541         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 542         dput(lower_dentry);
 543         if (!rc && d_really_is_positive(dentry))
 544                 clear_nlink(d_inode(dentry));
 545         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 546         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 547         unlock_dir(lower_dir_dentry);
 548         if (!rc)
 549                 d_drop(dentry);
 550         dput(dentry);
 551         return rc;
 552 }
 553
 554 static int
 555 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 556 {
 557         int rc;
 558         struct dentry *lower_dentry;
 559         struct dentry *lower_dir_dentry;
 560
 561         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 562         lower_dir_dentry = lock_parent(lower_dentry);
 563         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 564         if (rc || d_really_is_negative(lower_dentry))
 565                 goto out;
 566         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 567         if (rc)
 568                 goto out;
 569         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 570         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 571 out:
 572         unlock_dir(lower_dir_dentry);
 573         if (d_really_is_negative(dentry))
 574                 d_drop(dentry);
 575         return rc;
 576 }
 577
 578 static int
 579 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 580                 struct inode *new_dir, struct dentry *new_dentry,
 581                 unsigned int flags)
 582 {
 583         int rc;
 584         struct dentry *lower_old_dentry;
 585         struct dentry *lower_new_dentry;
 586         struct dentry *lower_old_dir_dentry;
 587         struct dentry *lower_new_dir_dentry;
 588         struct dentry *trap = NULL;
 589         struct inode *target_inode;
 590
 591         if (flags)
 592                 return -EINVAL;
 593
 594         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 595         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 596         dget(lower_old_dentry);
 597         dget(lower_new_dentry);
 598         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 599         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 600         target_inode = d_inode(new_dentry);
 601         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 602         /* source should not be ancestor of target */
 603         if (trap == lower_old_dentry) {
 604                 rc = -EINVAL;
 605                 goto out_lock;
 606         }
 607         /* target should not be ancestor of source */
 608         if (trap == lower_new_dentry) {
 609                 rc = -ENOTEMPTY;
 610                 goto out_lock;
 611         }
 612         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 613                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 614                         NULL, 0);
 615         if (rc)
 616                 goto out_lock;
 617         if (target_inode)
 618                 fsstack_copy_attr_all(target_inode,
 619                                       ecryptfs_inode_to_lower(target_inode));
 620         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 621         if (new_dir != old_dir)
 622                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 623 out_lock:
 624         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 625         dput(lower_new_dir_dentry);
 626         dput(lower_old_dir_dentry);
 627         dput(lower_new_dentry);
 628         dput(lower_old_dentry);
 629         return rc;
 630 }
 631
 632 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 633 {
 634         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 635         char *lower_buf;
 636         char *buf;
 637         mm_segment_t old_fs;
 638         int rc;
 639
 640         lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
 641         if (!lower_buf)
 642                 return ERR_PTR(-ENOMEM);
 643         old_fs = get_fs();
 644         set_fs(get_ds());
 645         rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
 646                                                    (char __user *)lower_buf,
 647                                                    PATH_MAX);
 648         set_fs(old_fs);
 649         if (rc < 0)
 650                 goto out;
 651         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 652                                                   lower_buf, rc);
 653 out:
 654         kfree(lower_buf);
 655         return rc ? ERR_PTR(rc) : buf;
 656 }
 657
 658 static const char *ecryptfs_get_link(struct dentry *dentry,
 659                                      struct inode *inode,
 660                                      struct delayed_call *done)
 661 {
 662         size_t len;
 663         char *buf;
 664
 665         if (!dentry)
 666                 return ERR_PTR(-ECHILD);
 667
 668         buf = ecryptfs_readlink_lower(dentry, &len);
 669         if (IS_ERR(buf))
 670                 return buf;
 671         fsstack_copy_attr_atime(d_inode(dentry),
 672                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 673         buf[len] = '\0';
 674         set_delayed_call(done, kfree_link, buf);
 675         return buf;
 676 }
 677
 678 /**
 679  * upper_size_to_lower_size
 680  * @crypt_stat: Crypt_stat associated with file
 681  * @upper_size: Size of the upper file
 682  *
 683  * Calculate the required size of the lower file based on the
 684  * specified size of the upper file. This calculation is based on the
 685  * number of headers in the underlying file and the extent size.
 686  *
 687  * Returns Calculated size of the lower file.
 688  */
 689 static loff_t
 690 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 691                          loff_t upper_size)
 692 {
 693         loff_t lower_size;
 694
 695         lower_size = ecryptfs_lower_header_size(crypt_stat);
 696         if (upper_size != 0) {
 697                 loff_t num_extents;
 698
 699                 num_extents = upper_size >> crypt_stat->extent_shift;
 700                 if (upper_size & ~crypt_stat->extent_mask)
 701                         num_extents++;
 702                 lower_size += (num_extents * crypt_stat->extent_size);
 703         }
 704         return lower_size;
 705 }
 706
 707 /**
 708  * truncate_upper
 709  * @dentry: The ecryptfs layer dentry
 710  * @ia: Address of the ecryptfs inode's attributes
 711  * @lower_ia: Address of the lower inode's attributes
 712  *
 713  * Function to handle truncations modifying the size of the file. Note
 714  * that the file sizes are interpolated. When expanding, we are simply
 715  * writing strings of 0's out. When truncating, we truncate the upper
 716  * inode and update the lower_ia according to the page index
 717  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 718  * the caller must use lower_ia in a call to notify_change() to perform
 719  * the truncation of the lower inode.
 720  *
 721  * Returns zero on success; non-zero otherwise
 722  */
 723 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 724                           struct iattr *lower_ia)
 725 {
 726         int rc = 0;
 727         struct inode *inode = d_inode(dentry);
 728         struct ecryptfs_crypt_stat *crypt_stat;
 729         loff_t i_size = i_size_read(inode);
 730         loff_t lower_size_before_truncate;
 731         loff_t lower_size_after_truncate;
 732
 733         if (unlikely((ia->ia_size == i_size))) {
 734                 lower_ia->ia_valid &= ~ATTR_SIZE;
 735                 return 0;
 736         }
 737         rc = ecryptfs_get_lower_file(dentry, inode);
 738         if (rc)
 739                 return rc;
 740         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 741         /* Switch on growing or shrinking file */
 742         if (ia->ia_size > i_size) {
 743                 char zero[] = { 0x00 };
 744
 745                 lower_ia->ia_valid &= ~ATTR_SIZE;
 746                 /* Write a single 0 at the last position of the file;
 747                  * this triggers code that will fill in 0's throughout
 748                  * the intermediate portion of the previous end of the
 749                  * file and the new and of the file */
 750                 rc = ecryptfs_write(inode, zero,
 751                                     (ia->ia_size - 1), 1);
 752         } else { /* ia->ia_size < i_size_read(inode) */
 753                 /* We're chopping off all the pages down to the page
 754                  * in which ia->ia_size is located. Fill in the end of
 755                  * that page from (ia->ia_size & ~PAGE_MASK) to
 756                  * PAGE_SIZE with zeros. */
 757                 size_t num_zeros = (PAGE_SIZE
 758                                     - (ia->ia_size & ~PAGE_MASK));
 759
 760                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 761                         truncate_setsize(inode, ia->ia_size);
 762                         lower_ia->ia_size = ia->ia_size;
 763                         lower_ia->ia_valid |= ATTR_SIZE;
 764                         goto out;
 765                 }
 766                 if (num_zeros) {
 767                         char *zeros_virt;
 768
 769                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 770                         if (!zeros_virt) {
 771                                 rc = -ENOMEM;
 772                                 goto out;
 773                         }
 774                         rc = ecryptfs_write(inode, zeros_virt,
 775                                             ia->ia_size, num_zeros);
 776                         kfree(zeros_virt);
 777                         if (rc) {
 778                                 printk(KERN_ERR "Error attempting to zero out "
 779                                        "the remainder of the end page on "
 780                                        "reducing truncate; rc = [%d]\n", rc);
 781                                 goto out;
 782                         }
 783                 }
 784                 truncate_setsize(inode, ia->ia_size);
 785                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 786                 if (rc) {
 787                         printk(KERN_ERR "Problem with "
 788                                "ecryptfs_write_inode_size_to_metadata; "
 789                                "rc = [%d]\n", rc);
 790                         goto out;
 791                 }
 792                 /* We are reducing the size of the ecryptfs file, and need to
 793                  * know if we need to reduce the size of the lower file. */
 794                 lower_size_before_truncate =
 795                     upper_size_to_lower_size(crypt_stat, i_size);
 796                 lower_size_after_truncate =
 797                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 798                 if (lower_size_after_truncate < lower_size_before_truncate) {
 799                         lower_ia->ia_size = lower_size_after_truncate;
 800                         lower_ia->ia_valid |= ATTR_SIZE;
 801                 } else
 802                         lower_ia->ia_valid &= ~ATTR_SIZE;
 803         }
 804 out:
 805         ecryptfs_put_lower_file(inode);
 806         return rc;
 807 }
 808
 809 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 810 {
 811         struct ecryptfs_crypt_stat *crypt_stat;
 812         loff_t lower_oldsize, lower_newsize;
 813
 814         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 815         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 816                                                  i_size_read(inode));
 817         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 818         if (lower_newsize > lower_oldsize) {
 819                 /*
 820                  * The eCryptfs inode and the new *lower* size are mixed here
 821                  * because we may not have the lower i_mutex held and/or it may
 822                  * not be appropriate to call inode_newsize_ok() with inodes
 823                  * from other filesystems.
 824                  */
 825                 return inode_newsize_ok(inode, lower_newsize);
 826         }
 827
 828         return 0;
 829 }
 830
 831 /**
 832  * ecryptfs_truncate
 833  * @dentry: The ecryptfs layer dentry
 834  * @new_length: The length to expand the file to
 835  *
 836  * Simple function that handles the truncation of an eCryptfs inode and
 837  * its corresponding lower inode.
 838  *
 839  * Returns zero on success; non-zero otherwise
 840  */
 841 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 842 {
 843         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 844         struct iattr lower_ia = { .ia_valid = 0 };
 845         int rc;
 846
 847         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 848         if (rc)
 849                 return rc;
 850
 851         rc = truncate_upper(dentry, &ia, &lower_ia);
 852         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 853                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 854
 855                 inode_lock(d_inode(lower_dentry));
 856                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 857                 inode_unlock(d_inode(lower_dentry));
 858         }
 859         return rc;
 860 }
 861
 862 static int
 863 ecryptfs_permission(struct inode *inode, int mask)
 864 {
 865         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 866 }
 867
 868 /**
 869  * ecryptfs_setattr
 870  * @dentry: dentry handle to the inode to modify
 871  * @ia: Structure with flags of what to change and values
 872  *
 873  * Updates the metadata of an inode. If the update is to the size
 874  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 875  * of both the ecryptfs inode and the lower inode.
 876  *
 877  * All other metadata changes will be passed right to the lower filesystem,
 878  * and we will just update our inode to look like the lower.
 879  */
 880 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 881 {
 882         int rc = 0;
 883         struct dentry *lower_dentry;
 884         struct iattr lower_ia;
 885         struct inode *inode;
 886         struct inode *lower_inode;
 887         struct ecryptfs_crypt_stat *crypt_stat;
 888
 889         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 890         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
 891                 rc = ecryptfs_init_crypt_stat(crypt_stat);
 892                 if (rc)
 893                         return rc;
 894         }
 895         inode = d_inode(dentry);
 896         lower_inode = ecryptfs_inode_to_lower(inode);
 897         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 898         mutex_lock(&crypt_stat->cs_mutex);
 899         if (d_is_dir(dentry))
 900                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 901         else if (d_is_reg(dentry)
 902                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 903                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 904                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 905
 906                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 907                         dentry->d_sb)->mount_crypt_stat;
 908                 rc = ecryptfs_get_lower_file(dentry, inode);
 909                 if (rc) {
 910                         mutex_unlock(&crypt_stat->cs_mutex);
 911                         goto out;
 912                 }
 913                 rc = ecryptfs_read_metadata(dentry);
 914                 ecryptfs_put_lower_file(inode);
 915                 if (rc) {
 916                         if (!(mount_crypt_stat->flags
 917                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 918                                 rc = -EIO;
 919                                 printk(KERN_WARNING "Either the lower file "
 920                                        "is not in a valid eCryptfs format, "
 921                                        "or the key could not be retrieved. "
 922                                        "Plaintext passthrough mode is not "
 923                                        "enabled; returning -EIO\n");
 924                                 mutex_unlock(&crypt_stat->cs_mutex);
 925                                 goto out;
 926                         }
 927                         rc = 0;
 928                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 929                                                | ECRYPTFS_ENCRYPTED);
 930                 }
 931         }
 932         mutex_unlock(&crypt_stat->cs_mutex);
 933
 934         rc = setattr_prepare(dentry, ia);
 935         if (rc)
 936                 goto out;
 937         if (ia->ia_valid & ATTR_SIZE) {
 938                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 939                 if (rc)
 940                         goto out;
 941         }
 942
 943         memcpy(&lower_ia, ia, sizeof(lower_ia));
 944         if (ia->ia_valid & ATTR_FILE)
 945                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 946         if (ia->ia_valid & ATTR_SIZE) {
 947                 rc = truncate_upper(dentry, ia, &lower_ia);
 948                 if (rc < 0)
 949                         goto out;
 950         }
 951
 952         /*
 953          * mode change is for clearing setuid/setgid bits. Allow lower fs
 954          * to interpret this in its own way.
 955          */
 956         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 957                 lower_ia.ia_valid &= ~ATTR_MODE;
 958
 959         inode_lock(d_inode(lower_dentry));
 960         rc = notify_change(lower_dentry, &lower_ia, NULL);
 961         inode_unlock(d_inode(lower_dentry));
 962 out:
 963         fsstack_copy_attr_all(inode, lower_inode);
 964         return rc;
 965 }
 966
 967 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
 968                                  struct kstat *stat)
 969 {
 970         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 971         int rc = 0;
 972
 973         mount_crypt_stat = &ecryptfs_superblock_to_private(
 974                                                 dentry->d_sb)->mount_crypt_stat;
 975         generic_fillattr(d_inode(dentry), stat);
 976         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 977                 char *target;
 978                 size_t targetsiz;
 979
 980                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 981                 if (!IS_ERR(target)) {
 982                         kfree(target);
 983                         stat->size = targetsiz;
 984                 } else {
 985                         rc = PTR_ERR(target);
 986                 }
 987         }
 988         return rc;
 989 }
 990
 991 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 992                             struct kstat *stat)
 993 {
 994         struct kstat lower_stat;
 995         int rc;
 996
 997         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
 998         if (!rc) {
 999                 fsstack_copy_attr_all(d_inode(dentry),
1000                                       ecryptfs_inode_to_lower(d_inode(dentry)));
1001                 generic_fillattr(d_inode(dentry), stat);
1002                 stat->blocks = lower_stat.blocks;
1003         }
1004         return rc;
1005 }
1006
1007 int
1008 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1009                   const char *name, const void *value,
1010                   size_t size, int flags)
1011 {
1012         int rc;
1013         struct dentry *lower_dentry;
1014
1015         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1016         if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1017                 rc = -EOPNOTSUPP;
1018                 goto out;
1019         }
1020         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1021         if (!rc && inode)
1022                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1023 out:
1024         return rc;
1025 }
1026
1027 ssize_t
1028 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1029                         const char *name, void *value, size_t size)
1030 {
1031         int rc;
1032
1033         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1034                 rc = -EOPNOTSUPP;
1035                 goto out;
1036         }
1037         inode_lock(lower_inode);
1038         rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1039         inode_unlock(lower_inode);
1040 out:
1041         return rc;
1042 }
1043
1044 static ssize_t
1045 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1046                   const char *name, void *value, size_t size)
1047 {
1048         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1049                                        ecryptfs_inode_to_lower(inode),
1050                                        name, value, size);
1051 }
1052
1053 static ssize_t
1054 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1055 {
1056         int rc = 0;
1057         struct dentry *lower_dentry;
1058
1059         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1060         if (!d_inode(lower_dentry)->i_op->listxattr) {
1061                 rc = -EOPNOTSUPP;
1062                 goto out;
1063         }
1064         inode_lock(d_inode(lower_dentry));
1065         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1066         inode_unlock(d_inode(lower_dentry));
1067 out:
1068         return rc;
1069 }
1070
1071 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1072                                 const char *name)
1073 {
1074         int rc;
1075         struct dentry *lower_dentry;
1076         struct inode *lower_inode;
1077
1078         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1079         lower_inode = ecryptfs_inode_to_lower(inode);
1080         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1081                 rc = -EOPNOTSUPP;
1082                 goto out;
1083         }
1084         inode_lock(lower_inode);
1085         rc = __vfs_removexattr(lower_dentry, name);
1086         inode_unlock(lower_inode);
1087 out:
1088         return rc;
1089 }
1090
1091 const struct inode_operations ecryptfs_symlink_iops = {
1092         .readlink = generic_readlink,
1093         .get_link = ecryptfs_get_link,
1094         .permission = ecryptfs_permission,
1095         .setattr = ecryptfs_setattr,
1096         .getattr = ecryptfs_getattr_link,
1097         .listxattr = ecryptfs_listxattr,
1098 };
1099
1100 const struct inode_operations ecryptfs_dir_iops = {
1101         .create = ecryptfs_create,
1102         .lookup = ecryptfs_lookup,
1103         .link = ecryptfs_link,
1104         .unlink = ecryptfs_unlink,
1105         .symlink = ecryptfs_symlink,
1106         .mkdir = ecryptfs_mkdir,
1107         .rmdir = ecryptfs_rmdir,
1108         .mknod = ecryptfs_mknod,
1109         .rename = ecryptfs_rename,
1110         .permission = ecryptfs_permission,
1111         .setattr = ecryptfs_setattr,
1112         .listxattr = ecryptfs_listxattr,
1113 };
1114
1115 const struct inode_operations ecryptfs_main_iops = {
1116         .permission = ecryptfs_permission,
1117         .setattr = ecryptfs_setattr,
1118         .getattr = ecryptfs_getattr,
1119         .listxattr = ecryptfs_listxattr,
1120 };
1121
1122 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1123                               struct dentry *dentry, struct inode *inode,
1124                               const char *name, void *buffer, size_t size)
1125 {
1126         return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1127 }
1128
1129 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1130                               struct dentry *dentry, struct inode *inode,
1131                               const char *name, const void *value, size_t size,
1132                               int flags)
1133 {
1134         if (value)
1135                 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1136         else {
1137                 BUG_ON(flags != XATTR_REPLACE);
1138                 return ecryptfs_removexattr(dentry, inode, name);
1139         }
1140 }
1141
1142 const struct xattr_handler ecryptfs_xattr_handler = {
1143         .prefix = "",  /* match anything */
1144         .get = ecryptfs_xattr_get,
1145         .set = ecryptfs_xattr_set,
1146 };
1147
1148 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1149         &ecryptfs_xattr_handler,
1150         NULL
1151 };