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 {
 582         int rc;
 583         struct dentry *lower_old_dentry;
 584         struct dentry *lower_new_dentry;
 585         struct dentry *lower_old_dir_dentry;
 586         struct dentry *lower_new_dir_dentry;
 587         struct dentry *trap = NULL;
 588         struct inode *target_inode;
 589
 590         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 591         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 592         dget(lower_old_dentry);
 593         dget(lower_new_dentry);
 594         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 595         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 596         target_inode = d_inode(new_dentry);
 597         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 598         /* source should not be ancestor of target */
 599         if (trap == lower_old_dentry) {
 600                 rc = -EINVAL;
 601                 goto out_lock;
 602         }
 603         /* target should not be ancestor of source */
 604         if (trap == lower_new_dentry) {
 605                 rc = -ENOTEMPTY;
 606                 goto out_lock;
 607         }
 608         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 609                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 610                         NULL, 0);
 611         if (rc)
 612                 goto out_lock;
 613         if (target_inode)
 614                 fsstack_copy_attr_all(target_inode,
 615                                       ecryptfs_inode_to_lower(target_inode));
 616         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 617         if (new_dir != old_dir)
 618                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 619 out_lock:
 620         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 621         dput(lower_new_dir_dentry);
 622         dput(lower_old_dir_dentry);
 623         dput(lower_new_dentry);
 624         dput(lower_old_dentry);
 625         return rc;
 626 }
 627
 628 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 629 {
 630         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 631         char *lower_buf;
 632         char *buf;
 633         mm_segment_t old_fs;
 634         int rc;
 635
 636         lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
 637         if (!lower_buf)
 638                 return ERR_PTR(-ENOMEM);
 639         old_fs = get_fs();
 640         set_fs(get_ds());
 641         rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
 642                                                    (char __user *)lower_buf,
 643                                                    PATH_MAX);
 644         set_fs(old_fs);
 645         if (rc < 0)
 646                 goto out;
 647         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 648                                                   lower_buf, rc);
 649 out:
 650         kfree(lower_buf);
 651         return rc ? ERR_PTR(rc) : buf;
 652 }
 653
 654 static const char *ecryptfs_get_link(struct dentry *dentry,
 655                                      struct inode *inode,
 656                                      struct delayed_call *done)
 657 {
 658         size_t len;
 659         char *buf;
 660
 661         if (!dentry)
 662                 return ERR_PTR(-ECHILD);
 663
 664         buf = ecryptfs_readlink_lower(dentry, &len);
 665         if (IS_ERR(buf))
 666                 return buf;
 667         fsstack_copy_attr_atime(d_inode(dentry),
 668                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 669         buf[len] = '\0';
 670         set_delayed_call(done, kfree_link, buf);
 671         return buf;
 672 }
 673
 674 /**
 675  * upper_size_to_lower_size
 676  * @crypt_stat: Crypt_stat associated with file
 677  * @upper_size: Size of the upper file
 678  *
 679  * Calculate the required size of the lower file based on the
 680  * specified size of the upper file. This calculation is based on the
 681  * number of headers in the underlying file and the extent size.
 682  *
 683  * Returns Calculated size of the lower file.
 684  */
 685 static loff_t
 686 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 687                          loff_t upper_size)
 688 {
 689         loff_t lower_size;
 690
 691         lower_size = ecryptfs_lower_header_size(crypt_stat);
 692         if (upper_size != 0) {
 693                 loff_t num_extents;
 694
 695                 num_extents = upper_size >> crypt_stat->extent_shift;
 696                 if (upper_size & ~crypt_stat->extent_mask)
 697                         num_extents++;
 698                 lower_size += (num_extents * crypt_stat->extent_size);
 699         }
 700         return lower_size;
 701 }
 702
 703 /**
 704  * truncate_upper
 705  * @dentry: The ecryptfs layer dentry
 706  * @ia: Address of the ecryptfs inode's attributes
 707  * @lower_ia: Address of the lower inode's attributes
 708  *
 709  * Function to handle truncations modifying the size of the file. Note
 710  * that the file sizes are interpolated. When expanding, we are simply
 711  * writing strings of 0's out. When truncating, we truncate the upper
 712  * inode and update the lower_ia according to the page index
 713  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 714  * the caller must use lower_ia in a call to notify_change() to perform
 715  * the truncation of the lower inode.
 716  *
 717  * Returns zero on success; non-zero otherwise
 718  */
 719 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 720                           struct iattr *lower_ia)
 721 {
 722         int rc = 0;
 723         struct inode *inode = d_inode(dentry);
 724         struct ecryptfs_crypt_stat *crypt_stat;
 725         loff_t i_size = i_size_read(inode);
 726         loff_t lower_size_before_truncate;
 727         loff_t lower_size_after_truncate;
 728
 729         if (unlikely((ia->ia_size == i_size))) {
 730                 lower_ia->ia_valid &= ~ATTR_SIZE;
 731                 return 0;
 732         }
 733         rc = ecryptfs_get_lower_file(dentry, inode);
 734         if (rc)
 735                 return rc;
 736         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 737         /* Switch on growing or shrinking file */
 738         if (ia->ia_size > i_size) {
 739                 char zero[] = { 0x00 };
 740
 741                 lower_ia->ia_valid &= ~ATTR_SIZE;
 742                 /* Write a single 0 at the last position of the file;
 743                  * this triggers code that will fill in 0's throughout
 744                  * the intermediate portion of the previous end of the
 745                  * file and the new and of the file */
 746                 rc = ecryptfs_write(inode, zero,
 747                                     (ia->ia_size - 1), 1);
 748         } else { /* ia->ia_size < i_size_read(inode) */
 749                 /* We're chopping off all the pages down to the page
 750                  * in which ia->ia_size is located. Fill in the end of
 751                  * that page from (ia->ia_size & ~PAGE_MASK) to
 752                  * PAGE_SIZE with zeros. */
 753                 size_t num_zeros = (PAGE_SIZE
 754                                     - (ia->ia_size & ~PAGE_MASK));
 755
 756                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 757                         truncate_setsize(inode, ia->ia_size);
 758                         lower_ia->ia_size = ia->ia_size;
 759                         lower_ia->ia_valid |= ATTR_SIZE;
 760                         goto out;
 761                 }
 762                 if (num_zeros) {
 763                         char *zeros_virt;
 764
 765                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 766                         if (!zeros_virt) {
 767                                 rc = -ENOMEM;
 768                                 goto out;
 769                         }
 770                         rc = ecryptfs_write(inode, zeros_virt,
 771                                             ia->ia_size, num_zeros);
 772                         kfree(zeros_virt);
 773                         if (rc) {
 774                                 printk(KERN_ERR "Error attempting to zero out "
 775                                        "the remainder of the end page on "
 776                                        "reducing truncate; rc = [%d]\n", rc);
 777                                 goto out;
 778                         }
 779                 }
 780                 truncate_setsize(inode, ia->ia_size);
 781                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 782                 if (rc) {
 783                         printk(KERN_ERR "Problem with "
 784                                "ecryptfs_write_inode_size_to_metadata; "
 785                                "rc = [%d]\n", rc);
 786                         goto out;
 787                 }
 788                 /* We are reducing the size of the ecryptfs file, and need to
 789                  * know if we need to reduce the size of the lower file. */
 790                 lower_size_before_truncate =
 791                     upper_size_to_lower_size(crypt_stat, i_size);
 792                 lower_size_after_truncate =
 793                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 794                 if (lower_size_after_truncate < lower_size_before_truncate) {
 795                         lower_ia->ia_size = lower_size_after_truncate;
 796                         lower_ia->ia_valid |= ATTR_SIZE;
 797                 } else
 798                         lower_ia->ia_valid &= ~ATTR_SIZE;
 799         }
 800 out:
 801         ecryptfs_put_lower_file(inode);
 802         return rc;
 803 }
 804
 805 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 806 {
 807         struct ecryptfs_crypt_stat *crypt_stat;
 808         loff_t lower_oldsize, lower_newsize;
 809
 810         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 811         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 812                                                  i_size_read(inode));
 813         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 814         if (lower_newsize > lower_oldsize) {
 815                 /*
 816                  * The eCryptfs inode and the new *lower* size are mixed here
 817                  * because we may not have the lower i_mutex held and/or it may
 818                  * not be appropriate to call inode_newsize_ok() with inodes
 819                  * from other filesystems.
 820                  */
 821                 return inode_newsize_ok(inode, lower_newsize);
 822         }
 823
 824         return 0;
 825 }
 826
 827 /**
 828  * ecryptfs_truncate
 829  * @dentry: The ecryptfs layer dentry
 830  * @new_length: The length to expand the file to
 831  *
 832  * Simple function that handles the truncation of an eCryptfs inode and
 833  * its corresponding lower inode.
 834  *
 835  * Returns zero on success; non-zero otherwise
 836  */
 837 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 838 {
 839         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 840         struct iattr lower_ia = { .ia_valid = 0 };
 841         int rc;
 842
 843         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 844         if (rc)
 845                 return rc;
 846
 847         rc = truncate_upper(dentry, &ia, &lower_ia);
 848         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 849                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 850
 851                 inode_lock(d_inode(lower_dentry));
 852                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 853                 inode_unlock(d_inode(lower_dentry));
 854         }
 855         return rc;
 856 }
 857
 858 static int
 859 ecryptfs_permission(struct inode *inode, int mask)
 860 {
 861         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 862 }
 863
 864 /**
 865  * ecryptfs_setattr
 866  * @dentry: dentry handle to the inode to modify
 867  * @ia: Structure with flags of what to change and values
 868  *
 869  * Updates the metadata of an inode. If the update is to the size
 870  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 871  * of both the ecryptfs inode and the lower inode.
 872  *
 873  * All other metadata changes will be passed right to the lower filesystem,
 874  * and we will just update our inode to look like the lower.
 875  */
 876 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 877 {
 878         int rc = 0;
 879         struct dentry *lower_dentry;
 880         struct iattr lower_ia;
 881         struct inode *inode;
 882         struct inode *lower_inode;
 883         struct ecryptfs_crypt_stat *crypt_stat;
 884
 885         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 886         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
 887                 rc = ecryptfs_init_crypt_stat(crypt_stat);
 888                 if (rc)
 889                         return rc;
 890         }
 891         inode = d_inode(dentry);
 892         lower_inode = ecryptfs_inode_to_lower(inode);
 893         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 894         mutex_lock(&crypt_stat->cs_mutex);
 895         if (d_is_dir(dentry))
 896                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 897         else if (d_is_reg(dentry)
 898                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 899                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 900                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 901
 902                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 903                         dentry->d_sb)->mount_crypt_stat;
 904                 rc = ecryptfs_get_lower_file(dentry, inode);
 905                 if (rc) {
 906                         mutex_unlock(&crypt_stat->cs_mutex);
 907                         goto out;
 908                 }
 909                 rc = ecryptfs_read_metadata(dentry);
 910                 ecryptfs_put_lower_file(inode);
 911                 if (rc) {
 912                         if (!(mount_crypt_stat->flags
 913                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 914                                 rc = -EIO;
 915                                 printk(KERN_WARNING "Either the lower file "
 916                                        "is not in a valid eCryptfs format, "
 917                                        "or the key could not be retrieved. "
 918                                        "Plaintext passthrough mode is not "
 919                                        "enabled; returning -EIO\n");
 920                                 mutex_unlock(&crypt_stat->cs_mutex);
 921                                 goto out;
 922                         }
 923                         rc = 0;
 924                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 925                                                | ECRYPTFS_ENCRYPTED);
 926                 }
 927         }
 928         mutex_unlock(&crypt_stat->cs_mutex);
 929
 930         rc = inode_change_ok(inode, ia);
 931         if (rc)
 932                 goto out;
 933         if (ia->ia_valid & ATTR_SIZE) {
 934                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 935                 if (rc)
 936                         goto out;
 937         }
 938
 939         memcpy(&lower_ia, ia, sizeof(lower_ia));
 940         if (ia->ia_valid & ATTR_FILE)
 941                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 942         if (ia->ia_valid & ATTR_SIZE) {
 943                 rc = truncate_upper(dentry, ia, &lower_ia);
 944                 if (rc < 0)
 945                         goto out;
 946         }
 947
 948         /*
 949          * mode change is for clearing setuid/setgid bits. Allow lower fs
 950          * to interpret this in its own way.
 951          */
 952         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 953                 lower_ia.ia_valid &= ~ATTR_MODE;
 954
 955         inode_lock(d_inode(lower_dentry));
 956         rc = notify_change(lower_dentry, &lower_ia, NULL);
 957         inode_unlock(d_inode(lower_dentry));
 958 out:
 959         fsstack_copy_attr_all(inode, lower_inode);
 960         return rc;
 961 }
 962
 963 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
 964                                  struct kstat *stat)
 965 {
 966         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 967         int rc = 0;
 968
 969         mount_crypt_stat = &ecryptfs_superblock_to_private(
 970                                                 dentry->d_sb)->mount_crypt_stat;
 971         generic_fillattr(d_inode(dentry), stat);
 972         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 973                 char *target;
 974                 size_t targetsiz;
 975
 976                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 977                 if (!IS_ERR(target)) {
 978                         kfree(target);
 979                         stat->size = targetsiz;
 980                 } else {
 981                         rc = PTR_ERR(target);
 982                 }
 983         }
 984         return rc;
 985 }
 986
 987 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 988                             struct kstat *stat)
 989 {
 990         struct kstat lower_stat;
 991         int rc;
 992
 993         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
 994         if (!rc) {
 995                 fsstack_copy_attr_all(d_inode(dentry),
 996                                       ecryptfs_inode_to_lower(d_inode(dentry)));
 997                 generic_fillattr(d_inode(dentry), stat);
 998                 stat->blocks = lower_stat.blocks;
 999         }
1000         return rc;
1001 }
1002
1003 int
1004 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1005                   const char *name, const void *value,
1006                   size_t size, int flags)
1007 {
1008         int rc = 0;
1009         struct dentry *lower_dentry;
1010
1011         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1012         if (!d_inode(lower_dentry)->i_op->setxattr) {
1013                 rc = -EOPNOTSUPP;
1014                 goto out;
1015         }
1016
1017         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1018         if (!rc && inode)
1019                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1020 out:
1021         return rc;
1022 }
1023
1024 ssize_t
1025 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1026                         const char *name, void *value, size_t size)
1027 {
1028         int rc = 0;
1029
1030         if (!lower_inode->i_op->getxattr) {
1031                 rc = -EOPNOTSUPP;
1032                 goto out;
1033         }
1034         inode_lock(lower_inode);
1035         rc = lower_inode->i_op->getxattr(lower_dentry, lower_inode,
1036                                          name, value, size);
1037         inode_unlock(lower_inode);
1038 out:
1039         return rc;
1040 }
1041
1042 static ssize_t
1043 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1044                   const char *name, void *value, size_t size)
1045 {
1046         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1047                                        ecryptfs_inode_to_lower(inode),
1048                                        name, value, size);
1049 }
1050
1051 static ssize_t
1052 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1053 {
1054         int rc = 0;
1055         struct dentry *lower_dentry;
1056
1057         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1058         if (!d_inode(lower_dentry)->i_op->listxattr) {
1059                 rc = -EOPNOTSUPP;
1060                 goto out;
1061         }
1062         inode_lock(d_inode(lower_dentry));
1063         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1064         inode_unlock(d_inode(lower_dentry));
1065 out:
1066         return rc;
1067 }
1068
1069 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1070 {
1071         int rc = 0;
1072         struct dentry *lower_dentry;
1073
1074         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1075         if (!d_inode(lower_dentry)->i_op->removexattr) {
1076                 rc = -EOPNOTSUPP;
1077                 goto out;
1078         }
1079         inode_lock(d_inode(lower_dentry));
1080         rc = d_inode(lower_dentry)->i_op->removexattr(lower_dentry, name);
1081         inode_unlock(d_inode(lower_dentry));
1082 out:
1083         return rc;
1084 }
1085
1086 const struct inode_operations ecryptfs_symlink_iops = {
1087         .readlink = generic_readlink,
1088         .get_link = ecryptfs_get_link,
1089         .permission = ecryptfs_permission,
1090         .setattr = ecryptfs_setattr,
1091         .getattr = ecryptfs_getattr_link,
1092         .setxattr = ecryptfs_setxattr,
1093         .getxattr = ecryptfs_getxattr,
1094         .listxattr = ecryptfs_listxattr,
1095         .removexattr = ecryptfs_removexattr
1096 };
1097
1098 const struct inode_operations ecryptfs_dir_iops = {
1099         .create = ecryptfs_create,
1100         .lookup = ecryptfs_lookup,
1101         .link = ecryptfs_link,
1102         .unlink = ecryptfs_unlink,
1103         .symlink = ecryptfs_symlink,
1104         .mkdir = ecryptfs_mkdir,
1105         .rmdir = ecryptfs_rmdir,
1106         .mknod = ecryptfs_mknod,
1107         .rename = ecryptfs_rename,
1108         .permission = ecryptfs_permission,
1109         .setattr = ecryptfs_setattr,
1110         .setxattr = ecryptfs_setxattr,
1111         .getxattr = ecryptfs_getxattr,
1112         .listxattr = ecryptfs_listxattr,
1113         .removexattr = ecryptfs_removexattr
1114 };
1115
1116 const struct inode_operations ecryptfs_main_iops = {
1117         .permission = ecryptfs_permission,
1118         .setattr = ecryptfs_setattr,
1119         .getattr = ecryptfs_getattr,
1120         .setxattr = ecryptfs_setxattr,
1121         .getxattr = ecryptfs_getxattr,
1122         .listxattr = ecryptfs_listxattr,
1123         .removexattr = ecryptfs_removexattr
1124 };