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_mapping->a_ops = &ecryptfs_aops;
  68
  69         if (S_ISLNK(inode->i_mode))
  70                 inode->i_op = &ecryptfs_symlink_iops;
  71         else if (S_ISDIR(inode->i_mode))
  72                 inode->i_op = &ecryptfs_dir_iops;
  73         else
  74                 inode->i_op = &ecryptfs_main_iops;
  75
  76         if (S_ISDIR(inode->i_mode))
  77                 inode->i_fop = &ecryptfs_dir_fops;
  78         else if (special_file(inode->i_mode))
  79                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
  80         else
  81                 inode->i_fop = &ecryptfs_main_fops;
  82
  83         return 0;
  84 }
  85
  86 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  87                                           struct super_block *sb)
  88 {
  89         struct inode *inode;
  90
  91         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  92                 return ERR_PTR(-EXDEV);
  93         if (!igrab(lower_inode))
  94                 return ERR_PTR(-ESTALE);
  95         inode = iget5_locked(sb, (unsigned long)lower_inode,
  96                              ecryptfs_inode_test, ecryptfs_inode_set,
  97                              lower_inode);
  98         if (!inode) {
  99                 iput(lower_inode);
 100                 return ERR_PTR(-EACCES);
 101         }
 102         if (!(inode->i_state & I_NEW))
 103                 iput(lower_inode);
 104
 105         return inode;
 106 }
 107
 108 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 109                                  struct super_block *sb)
 110 {
 111         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 112
 113         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 114                 unlock_new_inode(inode);
 115
 116         return inode;
 117 }
 118
 119 /**
 120  * ecryptfs_interpose
 121  * @lower_dentry: Existing dentry in the lower filesystem
 122  * @dentry: ecryptfs' dentry
 123  * @sb: ecryptfs's super_block
 124  *
 125  * Interposes upper and lower dentries.
 126  *
 127  * Returns zero on success; non-zero otherwise
 128  */
 129 static int ecryptfs_interpose(struct dentry *lower_dentry,
 130                               struct dentry *dentry, struct super_block *sb)
 131 {
 132         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 133
 134         if (IS_ERR(inode))
 135                 return PTR_ERR(inode);
 136         d_instantiate(dentry, inode);
 137
 138         return 0;
 139 }
 140
 141 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 142                               struct inode *inode)
 143 {
 144         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 145         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 146         struct dentry *lower_dir_dentry;
 147         int rc;
 148
 149         dget(lower_dentry);
 150         lower_dir_dentry = lock_parent(lower_dentry);
 151         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 152         if (rc) {
 153                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 154                 goto out_unlock;
 155         }
 156         fsstack_copy_attr_times(dir, lower_dir_inode);
 157         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 158         inode->i_ctime = dir->i_ctime;
 159         d_drop(dentry);
 160 out_unlock:
 161         unlock_dir(lower_dir_dentry);
 162         dput(lower_dentry);
 163         return rc;
 164 }
 165
 166 /**
 167  * ecryptfs_do_create
 168  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 169  * @ecryptfs_dentry: New file's dentry in ecryptfs
 170  * @mode: The mode of the new file
 171  *
 172  * Creates the underlying file and the eCryptfs inode which will link to
 173  * it. It will also update the eCryptfs directory inode to mimic the
 174  * stat of the lower directory inode.
 175  *
 176  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 177  */
 178 static struct inode *
 179 ecryptfs_do_create(struct inode *directory_inode,
 180                    struct dentry *ecryptfs_dentry, umode_t mode)
 181 {
 182         int rc;
 183         struct dentry *lower_dentry;
 184         struct dentry *lower_dir_dentry;
 185         struct inode *inode;
 186
 187         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 188         lower_dir_dentry = lock_parent(lower_dentry);
 189         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 190         if (rc) {
 191                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 192                        "rc = [%d]\n", __func__, rc);
 193                 inode = ERR_PTR(rc);
 194                 goto out_lock;
 195         }
 196         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 197                                      directory_inode->i_sb);
 198         if (IS_ERR(inode)) {
 199                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 200                 goto out_lock;
 201         }
 202         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 203         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 204 out_lock:
 205         unlock_dir(lower_dir_dentry);
 206         return inode;
 207 }
 208
 209 /**
 210  * ecryptfs_initialize_file
 211  *
 212  * Cause the file to be changed from a basic empty file to an ecryptfs
 213  * file with a header and first data page.
 214  *
 215  * Returns zero on success
 216  */
 217 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 218                              struct inode *ecryptfs_inode)
 219 {
 220         struct ecryptfs_crypt_stat *crypt_stat =
 221                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 222         int rc = 0;
 223
 224         if (S_ISDIR(ecryptfs_inode->i_mode)) {
 225                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 226                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 227                 goto out;
 228         }
 229         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 230         rc = ecryptfs_new_file_context(ecryptfs_inode);
 231         if (rc) {
 232                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 233                                 "context; rc = [%d]\n", rc);
 234                 goto out;
 235         }
 236         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 237         if (rc) {
 238                 printk(KERN_ERR "%s: Error attempting to initialize "
 239                         "the lower file for the dentry with name "
 240                         "[%pd]; rc = [%d]\n", __func__,
 241                         ecryptfs_dentry, rc);
 242                 goto out;
 243         }
 244         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 245         if (rc)
 246                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 247         ecryptfs_put_lower_file(ecryptfs_inode);
 248 out:
 249         return rc;
 250 }
 251
 252 /**
 253  * ecryptfs_create
 254  * @dir: The inode of the directory in which to create the file.
 255  * @dentry: The eCryptfs dentry
 256  * @mode: The mode of the new file.
 257  *
 258  * Creates a new file.
 259  *
 260  * Returns zero on success; non-zero on error condition
 261  */
 262 static int
 263 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 264                 umode_t mode, bool excl)
 265 {
 266         struct inode *ecryptfs_inode;
 267         int rc;
 268
 269         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 270                                             mode);
 271         if (IS_ERR(ecryptfs_inode)) {
 272                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 273                                 "lower filesystem\n");
 274                 rc = PTR_ERR(ecryptfs_inode);
 275                 goto out;
 276         }
 277         /* At this point, a file exists on "disk"; we need to make sure
 278          * that this on disk file is prepared to be an ecryptfs file */
 279         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 280         if (rc) {
 281                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 282                                    ecryptfs_inode);
 283                 iget_failed(ecryptfs_inode);
 284                 goto out;
 285         }
 286         d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
 287 out:
 288         return rc;
 289 }
 290
 291 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 292 {
 293         struct ecryptfs_crypt_stat *crypt_stat;
 294         int rc;
 295
 296         rc = ecryptfs_get_lower_file(dentry, inode);
 297         if (rc) {
 298                 printk(KERN_ERR "%s: Error attempting to initialize "
 299                         "the lower file for the dentry with name "
 300                         "[%pd]; rc = [%d]\n", __func__,
 301                         dentry, rc);
 302                 return rc;
 303         }
 304
 305         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 306         /* TODO: lock for crypt_stat comparison */
 307         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 308                 ecryptfs_set_default_sizes(crypt_stat);
 309
 310         rc = ecryptfs_read_and_validate_header_region(inode);
 311         ecryptfs_put_lower_file(inode);
 312         if (rc) {
 313                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
 314                 if (!rc)
 315                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 316         }
 317
 318         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
 319         return 0;
 320 }
 321
 322 /**
 323  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 324  */
 325 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
 326                                      struct dentry *lower_dentry)
 327 {
 328         struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
 329         struct inode *inode, *lower_inode;
 330         struct ecryptfs_dentry_info *dentry_info;
 331         int rc = 0;
 332
 333         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 334         if (!dentry_info) {
 335                 dput(lower_dentry);
 336                 return ERR_PTR(-ENOMEM);
 337         }
 338
 339         fsstack_copy_attr_atime(d_inode(dentry->d_parent),
 340                                 d_inode(path->dentry));
 341         BUG_ON(!d_count(lower_dentry));
 342
 343         ecryptfs_set_dentry_private(dentry, dentry_info);
 344         dentry_info->lower_path.mnt = mntget(path->mnt);
 345         dentry_info->lower_path.dentry = lower_dentry;
 346
 347         /*
 348          * negative dentry can go positive under us here - its parent is not
 349          * locked.  That's OK and that could happen just as we return from
 350          * ecryptfs_lookup() anyway.  Just need to be careful and fetch
 351          * ->d_inode only once - it's not stable here.
 352          */
 353         lower_inode = READ_ONCE(lower_dentry->d_inode);
 354
 355         if (!lower_inode) {
 356                 /* We want to add because we couldn't find in lower */
 357                 d_add(dentry, NULL);
 358                 return NULL;
 359         }
 360         inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
 361         if (IS_ERR(inode)) {
 362                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 363                        __func__, PTR_ERR(inode));
 364                 return ERR_CAST(inode);
 365         }
 366         if (S_ISREG(inode->i_mode)) {
 367                 rc = ecryptfs_i_size_read(dentry, inode);
 368                 if (rc) {
 369                         make_bad_inode(inode);
 370                         return ERR_PTR(rc);
 371                 }
 372         }
 373
 374         if (inode->i_state & I_NEW)
 375                 unlock_new_inode(inode);
 376         return d_splice_alias(inode, dentry);
 377 }
 378
 379 /**
 380  * ecryptfs_lookup
 381  * @ecryptfs_dir_inode: The eCryptfs directory inode
 382  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 383  * @flags: lookup flags
 384  *
 385  * Find a file on disk. If the file does not exist, then we'll add it to the
 386  * dentry cache and continue on to read it from the disk.
 387  */
 388 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 389                                       struct dentry *ecryptfs_dentry,
 390                                       unsigned int flags)
 391 {
 392         char *encrypted_and_encoded_name = NULL;
 393         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 394         struct dentry *lower_dir_dentry, *lower_dentry;
 395         const char *name = ecryptfs_dentry->d_name.name;
 396         size_t len = ecryptfs_dentry->d_name.len;
 397         struct dentry *res;
 398         int rc = 0;
 399
 400         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 401
 402         mount_crypt_stat = &ecryptfs_superblock_to_private(
 403                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 404         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 405                 rc = ecryptfs_encrypt_and_encode_filename(
 406                         &encrypted_and_encoded_name, &len,
 407                         mount_crypt_stat, name, len);
 408                 if (rc) {
 409                         printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 410                                "filename; rc = [%d]\n", __func__, rc);
 411                         return ERR_PTR(rc);
 412                 }
 413                 name = encrypted_and_encoded_name;
 414         }
 415
 416         lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
 417         if (IS_ERR(lower_dentry)) {
 418                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 419                                 "[%ld] on lower_dentry = [%s]\n", __func__,
 420                                 PTR_ERR(lower_dentry),
 421                                 name);
 422                 res = ERR_CAST(lower_dentry);
 423         } else {
 424                 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
 425         }
 426         kfree(encrypted_and_encoded_name);
 427         return res;
 428 }
 429
 430 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 431                          struct dentry *new_dentry)
 432 {
 433         struct dentry *lower_old_dentry;
 434         struct dentry *lower_new_dentry;
 435         struct dentry *lower_dir_dentry;
 436         u64 file_size_save;
 437         int rc;
 438
 439         file_size_save = i_size_read(d_inode(old_dentry));
 440         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 441         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 442         dget(lower_old_dentry);
 443         dget(lower_new_dentry);
 444         lower_dir_dentry = lock_parent(lower_new_dentry);
 445         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 446                       lower_new_dentry, NULL);
 447         if (rc || d_really_is_negative(lower_new_dentry))
 448                 goto out_lock;
 449         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 450         if (rc)
 451                 goto out_lock;
 452         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 453         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 454         set_nlink(d_inode(old_dentry),
 455                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 456         i_size_write(d_inode(new_dentry), file_size_save);
 457 out_lock:
 458         unlock_dir(lower_dir_dentry);
 459         dput(lower_new_dentry);
 460         dput(lower_old_dentry);
 461         return rc;
 462 }
 463
 464 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 465 {
 466         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 467 }
 468
 469 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 470                             const char *symname)
 471 {
 472         int rc;
 473         struct dentry *lower_dentry;
 474         struct dentry *lower_dir_dentry;
 475         char *encoded_symname;
 476         size_t encoded_symlen;
 477         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 478
 479         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 480         dget(lower_dentry);
 481         lower_dir_dentry = lock_parent(lower_dentry);
 482         mount_crypt_stat = &ecryptfs_superblock_to_private(
 483                 dir->i_sb)->mount_crypt_stat;
 484         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 485                                                   &encoded_symlen,
 486                                                   mount_crypt_stat, symname,
 487                                                   strlen(symname));
 488         if (rc)
 489                 goto out_lock;
 490         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 491                          encoded_symname);
 492         kfree(encoded_symname);
 493         if (rc || d_really_is_negative(lower_dentry))
 494                 goto out_lock;
 495         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 496         if (rc)
 497                 goto out_lock;
 498         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 499         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 500 out_lock:
 501         unlock_dir(lower_dir_dentry);
 502         dput(lower_dentry);
 503         if (d_really_is_negative(dentry))
 504                 d_drop(dentry);
 505         return rc;
 506 }
 507
 508 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 509 {
 510         int rc;
 511         struct dentry *lower_dentry;
 512         struct dentry *lower_dir_dentry;
 513
 514         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 515         lower_dir_dentry = lock_parent(lower_dentry);
 516         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 517         if (rc || d_really_is_negative(lower_dentry))
 518                 goto out;
 519         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 520         if (rc)
 521                 goto out;
 522         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 523         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 524         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 525 out:
 526         unlock_dir(lower_dir_dentry);
 527         if (d_really_is_negative(dentry))
 528                 d_drop(dentry);
 529         return rc;
 530 }
 531
 532 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 533 {
 534         struct dentry *lower_dentry;
 535         struct dentry *lower_dir_dentry;
 536         int rc;
 537
 538         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 539         dget(dentry);
 540         lower_dir_dentry = lock_parent(lower_dentry);
 541         dget(lower_dentry);
 542         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 543         dput(lower_dentry);
 544         if (!rc && d_really_is_positive(dentry))
 545                 clear_nlink(d_inode(dentry));
 546         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 547         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 548         unlock_dir(lower_dir_dentry);
 549         if (!rc)
 550                 d_drop(dentry);
 551         dput(dentry);
 552         return rc;
 553 }
 554
 555 static int
 556 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 557 {
 558         int rc;
 559         struct dentry *lower_dentry;
 560         struct dentry *lower_dir_dentry;
 561
 562         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 563         lower_dir_dentry = lock_parent(lower_dentry);
 564         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 565         if (rc || d_really_is_negative(lower_dentry))
 566                 goto out;
 567         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 568         if (rc)
 569                 goto out;
 570         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 571         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 572 out:
 573         unlock_dir(lower_dir_dentry);
 574         if (d_really_is_negative(dentry))
 575                 d_drop(dentry);
 576         return rc;
 577 }
 578
 579 static int
 580 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 581                 struct inode *new_dir, struct dentry *new_dentry,
 582                 unsigned int flags)
 583 {
 584         int rc;
 585         struct dentry *lower_old_dentry;
 586         struct dentry *lower_new_dentry;
 587         struct dentry *lower_old_dir_dentry;
 588         struct dentry *lower_new_dir_dentry;
 589         struct dentry *trap = NULL;
 590         struct inode *target_inode;
 591
 592         if (flags)
 593                 return -EINVAL;
 594
 595         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 596         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 597         dget(lower_old_dentry);
 598         dget(lower_new_dentry);
 599         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 600         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 601         target_inode = d_inode(new_dentry);
 602         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 603         /* source should not be ancestor of target */
 604         if (trap == lower_old_dentry) {
 605                 rc = -EINVAL;
 606                 goto out_lock;
 607         }
 608         /* target should not be ancestor of source */
 609         if (trap == lower_new_dentry) {
 610                 rc = -ENOTEMPTY;
 611                 goto out_lock;
 612         }
 613         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 614                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 615                         NULL, 0);
 616         if (rc)
 617                 goto out_lock;
 618         if (target_inode)
 619                 fsstack_copy_attr_all(target_inode,
 620                                       ecryptfs_inode_to_lower(target_inode));
 621         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 622         if (new_dir != old_dir)
 623                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 624 out_lock:
 625         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 626         dput(lower_new_dir_dentry);
 627         dput(lower_old_dir_dentry);
 628         dput(lower_new_dentry);
 629         dput(lower_old_dentry);
 630         return rc;
 631 }
 632
 633 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 634 {
 635         DEFINE_DELAYED_CALL(done);
 636         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 637         const char *link;
 638         char *buf;
 639         int rc;
 640
 641         link = vfs_get_link(lower_dentry, &done);
 642         if (IS_ERR(link))
 643                 return ERR_CAST(link);
 644
 645         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 646                                                   link, strlen(link));
 647         do_delayed_call(&done);
 648         if (rc)
 649                 return ERR_PTR(rc);
 650
 651         return 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 = setattr_prepare(dentry, 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(const struct path *path, struct kstat *stat,
 964                                  u32 request_mask, unsigned int flags)
 965 {
 966         struct dentry *dentry = path->dentry;
 967         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 968         int rc = 0;
 969
 970         mount_crypt_stat = &ecryptfs_superblock_to_private(
 971                                                 dentry->d_sb)->mount_crypt_stat;
 972         generic_fillattr(d_inode(dentry), stat);
 973         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 974                 char *target;
 975                 size_t targetsiz;
 976
 977                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 978                 if (!IS_ERR(target)) {
 979                         kfree(target);
 980                         stat->size = targetsiz;
 981                 } else {
 982                         rc = PTR_ERR(target);
 983                 }
 984         }
 985         return rc;
 986 }
 987
 988 static int ecryptfs_getattr(const struct path *path, struct kstat *stat,
 989                             u32 request_mask, unsigned int flags)
 990 {
 991         struct dentry *dentry = path->dentry;
 992         struct kstat lower_stat;
 993         int rc;
 994
 995         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
 996                          request_mask, flags);
 997         if (!rc) {
 998                 fsstack_copy_attr_all(d_inode(dentry),
 999                                       ecryptfs_inode_to_lower(d_inode(dentry)));
1000                 generic_fillattr(d_inode(dentry), stat);
1001                 stat->blocks = lower_stat.blocks;
1002         }
1003         return rc;
1004 }
1005
1006 int
1007 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1008                   const char *name, const void *value,
1009                   size_t size, int flags)
1010 {
1011         int rc;
1012         struct dentry *lower_dentry;
1013
1014         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1015         if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1016                 rc = -EOPNOTSUPP;
1017                 goto out;
1018         }
1019         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1020         if (!rc && inode)
1021                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1022 out:
1023         return rc;
1024 }
1025
1026 ssize_t
1027 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1028                         const char *name, void *value, size_t size)
1029 {
1030         int rc;
1031
1032         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1033                 rc = -EOPNOTSUPP;
1034                 goto out;
1035         }
1036         inode_lock(lower_inode);
1037         rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1038         inode_unlock(lower_inode);
1039 out:
1040         return rc;
1041 }
1042
1043 static ssize_t
1044 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1045                   const char *name, void *value, size_t size)
1046 {
1047         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1048                                        ecryptfs_inode_to_lower(inode),
1049                                        name, value, size);
1050 }
1051
1052 static ssize_t
1053 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1054 {
1055         int rc = 0;
1056         struct dentry *lower_dentry;
1057
1058         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1059         if (!d_inode(lower_dentry)->i_op->listxattr) {
1060                 rc = -EOPNOTSUPP;
1061                 goto out;
1062         }
1063         inode_lock(d_inode(lower_dentry));
1064         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1065         inode_unlock(d_inode(lower_dentry));
1066 out:
1067         return rc;
1068 }
1069
1070 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1071                                 const char *name)
1072 {
1073         int rc;
1074         struct dentry *lower_dentry;
1075         struct inode *lower_inode;
1076
1077         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1078         lower_inode = ecryptfs_inode_to_lower(inode);
1079         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1080                 rc = -EOPNOTSUPP;
1081                 goto out;
1082         }
1083         inode_lock(lower_inode);
1084         rc = __vfs_removexattr(lower_dentry, name);
1085         inode_unlock(lower_inode);
1086 out:
1087         return rc;
1088 }
1089
1090 const struct inode_operations ecryptfs_symlink_iops = {
1091         .get_link = ecryptfs_get_link,
1092         .permission = ecryptfs_permission,
1093         .setattr = ecryptfs_setattr,
1094         .getattr = ecryptfs_getattr_link,
1095         .listxattr = ecryptfs_listxattr,
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         .listxattr = ecryptfs_listxattr,
1111 };
1112
1113 const struct inode_operations ecryptfs_main_iops = {
1114         .permission = ecryptfs_permission,
1115         .setattr = ecryptfs_setattr,
1116         .getattr = ecryptfs_getattr,
1117         .listxattr = ecryptfs_listxattr,
1118 };
1119
1120 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1121                               struct dentry *dentry, struct inode *inode,
1122                               const char *name, void *buffer, size_t size)
1123 {
1124         return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1125 }
1126
1127 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1128                               struct dentry *dentry, struct inode *inode,
1129                               const char *name, const void *value, size_t size,
1130                               int flags)
1131 {
1132         if (value)
1133                 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1134         else {
1135                 BUG_ON(flags != XATTR_REPLACE);
1136                 return ecryptfs_removexattr(dentry, inode, name);
1137         }
1138 }
1139
1140 const struct xattr_handler ecryptfs_xattr_handler = {
1141         .prefix = "",  /* match anything */
1142         .get = ecryptfs_xattr_get,
1143         .set = ecryptfs_xattr_set,
1144 };
1145
1146 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1147         &ecryptfs_xattr_handler,
1148         NULL
1149 };