git.oblomov.eu Git - linux-2.6/blob - fs/ecryptfs/inode.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2004 Erez Zadok
   5  * Copyright (C) 2001-2004 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #include <linux/file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/dcache.h>
  30 #include <linux/namei.h>
  31 #include <linux/mount.h>
  32 #include <linux/crypto.h>
  33 #include <linux/fs_stack.h>
  34 #include <asm/unaligned.h>
  35 #include "ecryptfs_kernel.h"
  36
  37 static struct dentry *lock_parent(struct dentry *dentry)
  38 {
  39         struct dentry *dir;
  40
  41         dir = dget_parent(dentry);
  42         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
  43         return dir;
  44 }
  45
  46 static void unlock_dir(struct dentry *dir)
  47 {
  48         mutex_unlock(&dir->d_inode->i_mutex);
  49         dput(dir);
  50 }
  51
  52 /**
  53  * ecryptfs_create_underlying_file
  54  * @lower_dir_inode: inode of the parent in the lower fs of the new file
  55  * @lower_dentry: New file's dentry in the lower fs
  56  * @ecryptfs_dentry: New file's dentry in ecryptfs
  57  * @mode: The mode of the new file
  58  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  59  *
  60  * Creates the file in the lower file system.
  61  *
  62  * Returns zero on success; non-zero on error condition
  63  */
  64 static int
  65 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
  66                                 struct dentry *dentry, int mode,
  67                                 struct nameidata *nd)
  68 {
  69         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  70         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  71         struct dentry *dentry_save;
  72         struct vfsmount *vfsmount_save;
  73         int rc;
  74
  75         dentry_save = nd->path.dentry;
  76         vfsmount_save = nd->path.mnt;
  77         nd->path.dentry = lower_dentry;
  78         nd->path.mnt = lower_mnt;
  79         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
  80         nd->path.dentry = dentry_save;
  81         nd->path.mnt = vfsmount_save;
  82         return rc;
  83 }
  84
  85 /**
  86  * ecryptfs_do_create
  87  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
  88  * @ecryptfs_dentry: New file's dentry in ecryptfs
  89  * @mode: The mode of the new file
  90  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  91  *
  92  * Creates the underlying file and the eCryptfs inode which will link to
  93  * it. It will also update the eCryptfs directory inode to mimic the
  94  * stat of the lower directory inode.
  95  *
  96  * Returns zero on success; non-zero on error condition
  97  */
  98 static int
  99 ecryptfs_do_create(struct inode *directory_inode,
 100                    struct dentry *ecryptfs_dentry, int mode,
 101                    struct nameidata *nd)
 102 {
 103         int rc;
 104         struct dentry *lower_dentry;
 105         struct dentry *lower_dir_dentry;
 106
 107         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 108         lower_dir_dentry = lock_parent(lower_dentry);
 109         if (IS_ERR(lower_dir_dentry)) {
 110                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 111                                 "dentry\n");
 112                 rc = PTR_ERR(lower_dir_dentry);
 113                 goto out;
 114         }
 115         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 116                                              ecryptfs_dentry, mode, nd);
 117         if (rc) {
 118                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 119                        "rc = [%d]\n", __func__, rc);
 120                 goto out_lock;
 121         }
 122         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 123                                 directory_inode->i_sb, 0);
 124         if (rc) {
 125                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 126                 goto out_lock;
 127         }
 128         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
 129         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
 130 out_lock:
 131         unlock_dir(lower_dir_dentry);
 132 out:
 133         return rc;
 134 }
 135
 136 /**
 137  * grow_file
 138  * @ecryptfs_dentry: the eCryptfs dentry
 139  *
 140  * This is the code which will grow the file to its correct size.
 141  */
 142 static int grow_file(struct dentry *ecryptfs_dentry)
 143 {
 144         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
 145         struct file fake_file;
 146         struct ecryptfs_file_info tmp_file_info;
 147         char zero_virt[] = { 0x00 };
 148         int rc = 0;
 149
 150         memset(&fake_file, 0, sizeof(fake_file));
 151         fake_file.f_path.dentry = ecryptfs_dentry;
 152         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 153         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 154         ecryptfs_set_file_lower(
 155                 &fake_file,
 156                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
 157         rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
 158         i_size_write(ecryptfs_inode, 0);
 159         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
 160         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
 161                 ECRYPTFS_NEW_FILE;
 162         return rc;
 163 }
 164
 165 /**
 166  * ecryptfs_initialize_file
 167  *
 168  * Cause the file to be changed from a basic empty file to an ecryptfs
 169  * file with a header and first data page.
 170  *
 171  * Returns zero on success
 172  */
 173 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 174 {
 175         struct ecryptfs_crypt_stat *crypt_stat =
 176                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
 177         int rc = 0;
 178
 179         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 180                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 181                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 182                 goto out;
 183         }
 184         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
 185         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 186         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 187         if (rc) {
 188                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 189                                 "context; rc = [%d]\n", rc);
 190                 goto out;
 191         }
 192         if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
 193                 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
 194                 if (rc) {
 195                         printk(KERN_ERR "%s: Error attempting to initialize "
 196                                "the persistent file for the dentry with name "
 197                                "[%s]; rc = [%d]\n", __func__,
 198                                ecryptfs_dentry->d_name.name, rc);
 199                         goto out;
 200                 }
 201         }
 202         rc = ecryptfs_write_metadata(ecryptfs_dentry);
 203         if (rc) {
 204                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 205                 goto out;
 206         }
 207         rc = grow_file(ecryptfs_dentry);
 208         if (rc)
 209                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
 210 out:
 211         return rc;
 212 }
 213
 214 /**
 215  * ecryptfs_create
 216  * @dir: The inode of the directory in which to create the file.
 217  * @dentry: The eCryptfs dentry
 218  * @mode: The mode of the new file.
 219  * @nd: nameidata
 220  *
 221  * Creates a new file.
 222  *
 223  * Returns zero on success; non-zero on error condition
 224  */
 225 static int
 226 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 227                 int mode, struct nameidata *nd)
 228 {
 229         int rc;
 230
 231         /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
 232          * the crypt_stat->lower_file (persistent file) */
 233         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 234         if (unlikely(rc)) {
 235                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 236                                 "lower filesystem\n");
 237                 goto out;
 238         }
 239         /* At this point, a file exists on "disk"; we need to make sure
 240          * that this on disk file is prepared to be an ecryptfs file */
 241         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 242 out:
 243         return rc;
 244 }
 245
 246 /**
 247  * ecryptfs_lookup
 248  * @dir: inode
 249  * @dentry: The dentry
 250  * @nd: nameidata, may be NULL
 251  *
 252  * Find a file on disk. If the file does not exist, then we'll add it to the
 253  * dentry cache and continue on to read it from the disk.
 254  */
 255 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 256                                       struct nameidata *nd)
 257 {
 258         int rc = 0;
 259         struct dentry *lower_dir_dentry;
 260         struct dentry *lower_dentry;
 261         struct vfsmount *lower_mnt;
 262         char *encoded_name;
 263         int encoded_namelen;
 264         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 265         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 266         char *page_virt = NULL;
 267         struct inode *lower_inode;
 268         u64 file_size;
 269
 270         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 271         dentry->d_op = &ecryptfs_dops;
 272         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 273             || (dentry->d_name.len == 2
 274                 && !strcmp(dentry->d_name.name, ".."))) {
 275                 d_drop(dentry);
 276                 goto out;
 277         }
 278         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 279                                                    dentry->d_name.name,
 280                                                    dentry->d_name.len,
 281                                                    &encoded_name);
 282         if (encoded_namelen < 0) {
 283                 rc = encoded_namelen;
 284                 d_drop(dentry);
 285                 goto out;
 286         }
 287         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 288                         "= [%d]\n", encoded_name, encoded_namelen);
 289         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 290                                       encoded_namelen - 1);
 291         kfree(encoded_name);
 292         if (IS_ERR(lower_dentry)) {
 293                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 294                 rc = PTR_ERR(lower_dentry);
 295                 d_drop(dentry);
 296                 goto out;
 297         }
 298         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 299         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 300                 "d_name.name = [%s]\n", lower_dentry,
 301                 lower_dentry->d_name.name);
 302         lower_inode = lower_dentry->d_inode;
 303         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 304         BUG_ON(!atomic_read(&lower_dentry->d_count));
 305         ecryptfs_set_dentry_private(dentry,
 306                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 307                                                      GFP_KERNEL));
 308         if (!ecryptfs_dentry_to_private(dentry)) {
 309                 rc = -ENOMEM;
 310                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 311                                 "to allocate ecryptfs_dentry_info struct\n");
 312                 goto out_dput;
 313         }
 314         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 315         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 316         if (!lower_dentry->d_inode) {
 317                 /* We want to add because we couldn't find in lower */
 318                 d_add(dentry, NULL);
 319                 goto out;
 320         }
 321         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb,
 322                                 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
 323         if (rc) {
 324                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 325                 goto out;
 326         }
 327         if (S_ISDIR(lower_inode->i_mode)) {
 328                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 329                 goto out;
 330         }
 331         if (S_ISLNK(lower_inode->i_mode)) {
 332                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 333                 goto out;
 334         }
 335         if (special_file(lower_inode->i_mode)) {
 336                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
 337                 goto out;
 338         }
 339         if (!nd) {
 340                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 341                                 "as we *think* we are about to unlink\n");
 342                 goto out;
 343         }
 344         /* Released in this function */
 345         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 346                                       GFP_USER);
 347         if (!page_virt) {
 348                 rc = -ENOMEM;
 349                 ecryptfs_printk(KERN_ERR,
 350                                 "Cannot ecryptfs_kmalloc a page\n");
 351                 goto out;
 352         }
 353         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 354         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 355                 ecryptfs_set_default_sizes(crypt_stat);
 356         if (!ecryptfs_inode_to_private(dentry->d_inode)->lower_file) {
 357                 rc = ecryptfs_init_persistent_file(dentry);
 358                 if (rc) {
 359                         printk(KERN_ERR "%s: Error attempting to initialize "
 360                                "the persistent file for the dentry with name "
 361                                "[%s]; rc = [%d]\n", __func__,
 362                                dentry->d_name.name, rc);
 363                         goto out;
 364                 }
 365         }
 366         rc = ecryptfs_read_and_validate_header_region(page_virt,
 367                                                       dentry->d_inode);
 368         if (rc) {
 369                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 370                 if (rc) {
 371                         printk(KERN_DEBUG "Valid metadata not found in header "
 372                                "region or xattr region; treating file as "
 373                                "unencrypted\n");
 374                         rc = 0;
 375                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 376                         goto out;
 377                 }
 378                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 379         }
 380         mount_crypt_stat = &ecryptfs_superblock_to_private(
 381                 dentry->d_sb)->mount_crypt_stat;
 382         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 383                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 384                         file_size = (crypt_stat->num_header_bytes_at_front
 385                                      + i_size_read(lower_dentry->d_inode));
 386                 else
 387                         file_size = i_size_read(lower_dentry->d_inode);
 388         } else {
 389                 file_size = get_unaligned_be64(page_virt);
 390         }
 391         i_size_write(dentry->d_inode, (loff_t)file_size);
 392         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 393         goto out;
 394
 395 out_dput:
 396         dput(lower_dentry);
 397         d_drop(dentry);
 398 out:
 399         return ERR_PTR(rc);
 400 }
 401
 402 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 403                          struct dentry *new_dentry)
 404 {
 405         struct dentry *lower_old_dentry;
 406         struct dentry *lower_new_dentry;
 407         struct dentry *lower_dir_dentry;
 408         u64 file_size_save;
 409         int rc;
 410
 411         file_size_save = i_size_read(old_dentry->d_inode);
 412         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 413         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 414         dget(lower_old_dentry);
 415         dget(lower_new_dentry);
 416         lower_dir_dentry = lock_parent(lower_new_dentry);
 417         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 418                       lower_new_dentry);
 419         if (rc || !lower_new_dentry->d_inode)
 420                 goto out_lock;
 421         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 422         if (rc)
 423                 goto out_lock;
 424         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 425         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 426         old_dentry->d_inode->i_nlink =
 427                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 428         i_size_write(new_dentry->d_inode, file_size_save);
 429 out_lock:
 430         unlock_dir(lower_dir_dentry);
 431         dput(lower_new_dentry);
 432         dput(lower_old_dentry);
 433         d_drop(lower_old_dentry);
 434         d_drop(new_dentry);
 435         d_drop(old_dentry);
 436         return rc;
 437 }
 438
 439 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 440 {
 441         int rc = 0;
 442         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 443         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 444         struct dentry *lower_dir_dentry;
 445
 446         lower_dir_dentry = lock_parent(lower_dentry);
 447         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 448         if (rc) {
 449                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 450                 goto out_unlock;
 451         }
 452         fsstack_copy_attr_times(dir, lower_dir_inode);
 453         dentry->d_inode->i_nlink =
 454                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 455         dentry->d_inode->i_ctime = dir->i_ctime;
 456         d_drop(dentry);
 457 out_unlock:
 458         unlock_dir(lower_dir_dentry);
 459         return rc;
 460 }
 461
 462 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 463                             const char *symname)
 464 {
 465         int rc;
 466         struct dentry *lower_dentry;
 467         struct dentry *lower_dir_dentry;
 468         char *encoded_symname;
 469         int encoded_symlen;
 470         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 471
 472         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 473         dget(lower_dentry);
 474         lower_dir_dentry = lock_parent(lower_dentry);
 475         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 476                                                   strlen(symname),
 477                                                   &encoded_symname);
 478         if (encoded_symlen < 0) {
 479                 rc = encoded_symlen;
 480                 goto out_lock;
 481         }
 482         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 483                          encoded_symname);
 484         kfree(encoded_symname);
 485         if (rc || !lower_dentry->d_inode)
 486                 goto out_lock;
 487         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 488         if (rc)
 489                 goto out_lock;
 490         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 491         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 492 out_lock:
 493         unlock_dir(lower_dir_dentry);
 494         dput(lower_dentry);
 495         if (!dentry->d_inode)
 496                 d_drop(dentry);
 497         return rc;
 498 }
 499
 500 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 501 {
 502         int rc;
 503         struct dentry *lower_dentry;
 504         struct dentry *lower_dir_dentry;
 505
 506         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 507         lower_dir_dentry = lock_parent(lower_dentry);
 508         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 509         if (rc || !lower_dentry->d_inode)
 510                 goto out;
 511         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 512         if (rc)
 513                 goto out;
 514         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 515         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 516         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 517 out:
 518         unlock_dir(lower_dir_dentry);
 519         if (!dentry->d_inode)
 520                 d_drop(dentry);
 521         return rc;
 522 }
 523
 524 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 525 {
 526         struct dentry *lower_dentry;
 527         struct dentry *lower_dir_dentry;
 528         int rc;
 529
 530         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 531         dget(dentry);
 532         lower_dir_dentry = lock_parent(lower_dentry);
 533         dget(lower_dentry);
 534         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 535         dput(lower_dentry);
 536         if (!rc)
 537                 d_delete(lower_dentry);
 538         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 539         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 540         unlock_dir(lower_dir_dentry);
 541         if (!rc)
 542                 d_drop(dentry);
 543         dput(dentry);
 544         return rc;
 545 }
 546
 547 static int
 548 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 549 {
 550         int rc;
 551         struct dentry *lower_dentry;
 552         struct dentry *lower_dir_dentry;
 553
 554         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 555         lower_dir_dentry = lock_parent(lower_dentry);
 556         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 557         if (rc || !lower_dentry->d_inode)
 558                 goto out;
 559         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 560         if (rc)
 561                 goto out;
 562         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 563         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 564 out:
 565         unlock_dir(lower_dir_dentry);
 566         if (!dentry->d_inode)
 567                 d_drop(dentry);
 568         return rc;
 569 }
 570
 571 static int
 572 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 573                 struct inode *new_dir, struct dentry *new_dentry)
 574 {
 575         int rc;
 576         struct dentry *lower_old_dentry;
 577         struct dentry *lower_new_dentry;
 578         struct dentry *lower_old_dir_dentry;
 579         struct dentry *lower_new_dir_dentry;
 580
 581         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 582         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 583         dget(lower_old_dentry);
 584         dget(lower_new_dentry);
 585         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 586         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 587         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 588         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 589                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 590         if (rc)
 591                 goto out_lock;
 592         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 593         if (new_dir != old_dir)
 594                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 595 out_lock:
 596         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 597         dput(lower_new_dentry->d_parent);
 598         dput(lower_old_dentry->d_parent);
 599         dput(lower_new_dentry);
 600         dput(lower_old_dentry);
 601         return rc;
 602 }
 603
 604 static int
 605 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 606 {
 607         int rc;
 608         struct dentry *lower_dentry;
 609         char *decoded_name;
 610         char *lower_buf;
 611         mm_segment_t old_fs;
 612         struct ecryptfs_crypt_stat *crypt_stat;
 613
 614         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 615         if (!lower_dentry->d_inode->i_op ||
 616             !lower_dentry->d_inode->i_op->readlink) {
 617                 rc = -EINVAL;
 618                 goto out;
 619         }
 620         /* Released in this function */
 621         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 622         if (lower_buf == NULL) {
 623                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 624                 rc = -ENOMEM;
 625                 goto out;
 626         }
 627         old_fs = get_fs();
 628         set_fs(get_ds());
 629         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 630                         "lower_dentry->d_name.name = [%s]\n",
 631                         lower_dentry->d_name.name);
 632         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 633                                                    (char __user *)lower_buf,
 634                                                    bufsiz);
 635         set_fs(old_fs);
 636         if (rc >= 0) {
 637                 crypt_stat = NULL;
 638                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 639                                               &decoded_name);
 640                 if (rc == -ENOMEM)
 641                         goto out_free_lower_buf;
 642                 if (rc > 0) {
 643                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 644                                         "to userspace: [%*s]\n", rc,
 645                                         decoded_name);
 646                         if (copy_to_user(buf, decoded_name, rc))
 647                                 rc = -EFAULT;
 648                 }
 649                 kfree(decoded_name);
 650                 fsstack_copy_attr_atime(dentry->d_inode,
 651                                         lower_dentry->d_inode);
 652         }
 653 out_free_lower_buf:
 654         kfree(lower_buf);
 655 out:
 656         return rc;
 657 }
 658
 659 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 660 {
 661         char *buf;
 662         int len = PAGE_SIZE, rc;
 663         mm_segment_t old_fs;
 664
 665         /* Released in ecryptfs_put_link(); only release here on error */
 666         buf = kmalloc(len, GFP_KERNEL);
 667         if (!buf) {
 668                 rc = -ENOMEM;
 669                 goto out;
 670         }
 671         old_fs = get_fs();
 672         set_fs(get_ds());
 673         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 674                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 675         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 676         buf[rc] = '\0';
 677         set_fs(old_fs);
 678         if (rc < 0)
 679                 goto out_free;
 680         rc = 0;
 681         nd_set_link(nd, buf);
 682         goto out;
 683 out_free:
 684         kfree(buf);
 685 out:
 686         return ERR_PTR(rc);
 687 }
 688
 689 static void
 690 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 691 {
 692         /* Free the char* */
 693         kfree(nd_get_link(nd));
 694 }
 695
 696 /**
 697  * upper_size_to_lower_size
 698  * @crypt_stat: Crypt_stat associated with file
 699  * @upper_size: Size of the upper file
 700  *
 701  * Calculate the required size of the lower file based on the
 702  * specified size of the upper file. This calculation is based on the
 703  * number of headers in the underlying file and the extent size.
 704  *
 705  * Returns Calculated size of the lower file.
 706  */
 707 static loff_t
 708 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 709                          loff_t upper_size)
 710 {
 711         loff_t lower_size;
 712
 713         lower_size = crypt_stat->num_header_bytes_at_front;
 714         if (upper_size != 0) {
 715                 loff_t num_extents;
 716
 717                 num_extents = upper_size >> crypt_stat->extent_shift;
 718                 if (upper_size & ~crypt_stat->extent_mask)
 719                         num_extents++;
 720                 lower_size += (num_extents * crypt_stat->extent_size);
 721         }
 722         return lower_size;
 723 }
 724
 725 /**
 726  * ecryptfs_truncate
 727  * @dentry: The ecryptfs layer dentry
 728  * @new_length: The length to expand the file to
 729  *
 730  * Function to handle truncations modifying the size of the file. Note
 731  * that the file sizes are interpolated. When expanding, we are simply
 732  * writing strings of 0's out. When truncating, we need to modify the
 733  * underlying file size according to the page index interpolations.
 734  *
 735  * Returns zero on success; non-zero otherwise
 736  */
 737 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 738 {
 739         int rc = 0;
 740         struct inode *inode = dentry->d_inode;
 741         struct dentry *lower_dentry;
 742         struct file fake_ecryptfs_file;
 743         struct ecryptfs_crypt_stat *crypt_stat;
 744         loff_t i_size = i_size_read(inode);
 745         loff_t lower_size_before_truncate;
 746         loff_t lower_size_after_truncate;
 747
 748         if (unlikely((new_length == i_size)))
 749                 goto out;
 750         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 751         /* Set up a fake ecryptfs file, this is used to interface with
 752          * the file in the underlying filesystem so that the
 753          * truncation has an effect there as well. */
 754         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 755         fake_ecryptfs_file.f_path.dentry = dentry;
 756         /* Released at out_free: label */
 757         ecryptfs_set_file_private(&fake_ecryptfs_file,
 758                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 759                                                    GFP_KERNEL));
 760         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 761                 rc = -ENOMEM;
 762                 goto out;
 763         }
 764         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 765         ecryptfs_set_file_lower(
 766                 &fake_ecryptfs_file,
 767                 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
 768         /* Switch on growing or shrinking file */
 769         if (new_length > i_size) {
 770                 char zero[] = { 0x00 };
 771
 772                 /* Write a single 0 at the last position of the file;
 773                  * this triggers code that will fill in 0's throughout
 774                  * the intermediate portion of the previous end of the
 775                  * file and the new and of the file */
 776                 rc = ecryptfs_write(&fake_ecryptfs_file, zero,
 777                                     (new_length - 1), 1);
 778         } else { /* new_length < i_size_read(inode) */
 779                 /* We're chopping off all the pages down do the page
 780                  * in which new_length is located. Fill in the end of
 781                  * that page from (new_length & ~PAGE_CACHE_MASK) to
 782                  * PAGE_CACHE_SIZE with zeros. */
 783                 size_t num_zeros = (PAGE_CACHE_SIZE
 784                                     - (new_length & ~PAGE_CACHE_MASK));
 785
 786                 if (num_zeros) {
 787                         char *zeros_virt;
 788
 789                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 790                         if (!zeros_virt) {
 791                                 rc = -ENOMEM;
 792                                 goto out_free;
 793                         }
 794                         rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
 795                                             new_length, num_zeros);
 796                         kfree(zeros_virt);
 797                         if (rc) {
 798                                 printk(KERN_ERR "Error attempting to zero out "
 799                                        "the remainder of the end page on "
 800                                        "reducing truncate; rc = [%d]\n", rc);
 801                                 goto out_free;
 802                         }
 803                 }
 804                 vmtruncate(inode, new_length);
 805                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 806                 if (rc) {
 807                         printk(KERN_ERR "Problem with "
 808                                "ecryptfs_write_inode_size_to_metadata; "
 809                                "rc = [%d]\n", rc);
 810                         goto out_free;
 811                 }
 812                 /* We are reducing the size of the ecryptfs file, and need to
 813                  * know if we need to reduce the size of the lower file. */
 814                 lower_size_before_truncate =
 815                     upper_size_to_lower_size(crypt_stat, i_size);
 816                 lower_size_after_truncate =
 817                     upper_size_to_lower_size(crypt_stat, new_length);
 818                 if (lower_size_after_truncate < lower_size_before_truncate)
 819                         vmtruncate(lower_dentry->d_inode,
 820                                    lower_size_after_truncate);
 821         }
 822 out_free:
 823         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 824                 kmem_cache_free(ecryptfs_file_info_cache,
 825                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 826 out:
 827         return rc;
 828 }
 829
 830 static int
 831 ecryptfs_permission(struct inode *inode, int mask)
 832 {
 833         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 834 }
 835
 836 /**
 837  * ecryptfs_setattr
 838  * @dentry: dentry handle to the inode to modify
 839  * @ia: Structure with flags of what to change and values
 840  *
 841  * Updates the metadata of an inode. If the update is to the size
 842  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 843  * of both the ecryptfs inode and the lower inode.
 844  *
 845  * All other metadata changes will be passed right to the lower filesystem,
 846  * and we will just update our inode to look like the lower.
 847  */
 848 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 849 {
 850         int rc = 0;
 851         struct dentry *lower_dentry;
 852         struct inode *inode;
 853         struct inode *lower_inode;
 854         struct ecryptfs_crypt_stat *crypt_stat;
 855
 856         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 857         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 858                 ecryptfs_init_crypt_stat(crypt_stat);
 859         inode = dentry->d_inode;
 860         lower_inode = ecryptfs_inode_to_lower(inode);
 861         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 862         mutex_lock(&crypt_stat->cs_mutex);
 863         if (S_ISDIR(dentry->d_inode->i_mode))
 864                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 865         else if (S_ISREG(dentry->d_inode->i_mode)
 866                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 867                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 868                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 869
 870                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 871                         dentry->d_sb)->mount_crypt_stat;
 872                 rc = ecryptfs_read_metadata(dentry);
 873                 if (rc) {
 874                         if (!(mount_crypt_stat->flags
 875                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 876                                 rc = -EIO;
 877                                 printk(KERN_WARNING "Either the lower file "
 878                                        "is not in a valid eCryptfs format, "
 879                                        "or the key could not be retrieved. "
 880                                        "Plaintext passthrough mode is not "
 881                                        "enabled; returning -EIO\n");
 882                                 mutex_unlock(&crypt_stat->cs_mutex);
 883                                 goto out;
 884                         }
 885                         rc = 0;
 886                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 887                         mutex_unlock(&crypt_stat->cs_mutex);
 888                         goto out;
 889                 }
 890         }
 891         mutex_unlock(&crypt_stat->cs_mutex);
 892         if (ia->ia_valid & ATTR_SIZE) {
 893                 ecryptfs_printk(KERN_DEBUG,
 894                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 895                                 ia->ia_valid, ATTR_SIZE);
 896                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 897                 /* ecryptfs_truncate handles resizing of the lower file */
 898                 ia->ia_valid &= ~ATTR_SIZE;
 899                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 900                                 ia->ia_valid);
 901                 if (rc < 0)
 902                         goto out;
 903         }
 904
 905         /*
 906          * mode change is for clearing setuid/setgid bits. Allow lower fs
 907          * to interpret this in its own way.
 908          */
 909         if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 910                 ia->ia_valid &= ~ATTR_MODE;
 911
 912         mutex_lock(&lower_dentry->d_inode->i_mutex);
 913         rc = notify_change(lower_dentry, ia);
 914         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 915 out:
 916         fsstack_copy_attr_all(inode, lower_inode, NULL);
 917         return rc;
 918 }
 919
 920 int
 921 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 922                   size_t size, int flags)
 923 {
 924         int rc = 0;
 925         struct dentry *lower_dentry;
 926
 927         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 928         if (!lower_dentry->d_inode->i_op->setxattr) {
 929                 rc = -ENOSYS;
 930                 goto out;
 931         }
 932         mutex_lock(&lower_dentry->d_inode->i_mutex);
 933         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 934                                                    size, flags);
 935         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 936 out:
 937         return rc;
 938 }
 939
 940 ssize_t
 941 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
 942                         void *value, size_t size)
 943 {
 944         int rc = 0;
 945
 946         if (!lower_dentry->d_inode->i_op->getxattr) {
 947                 rc = -ENOSYS;
 948                 goto out;
 949         }
 950         mutex_lock(&lower_dentry->d_inode->i_mutex);
 951         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 952                                                    size);
 953         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 954 out:
 955         return rc;
 956 }
 957
 958 static ssize_t
 959 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 960                   size_t size)
 961 {
 962         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
 963                                        value, size);
 964 }
 965
 966 static ssize_t
 967 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 968 {
 969         int rc = 0;
 970         struct dentry *lower_dentry;
 971
 972         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 973         if (!lower_dentry->d_inode->i_op->listxattr) {
 974                 rc = -ENOSYS;
 975                 goto out;
 976         }
 977         mutex_lock(&lower_dentry->d_inode->i_mutex);
 978         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
 979         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 980 out:
 981         return rc;
 982 }
 983
 984 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
 985 {
 986         int rc = 0;
 987         struct dentry *lower_dentry;
 988
 989         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 990         if (!lower_dentry->d_inode->i_op->removexattr) {
 991                 rc = -ENOSYS;
 992                 goto out;
 993         }
 994         mutex_lock(&lower_dentry->d_inode->i_mutex);
 995         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
 996         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 997 out:
 998         return rc;
 999 }
1000
1001 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1002 {
1003         if ((ecryptfs_inode_to_lower(inode)
1004              == (struct inode *)candidate_lower_inode))
1005                 return 1;
1006         else
1007                 return 0;
1008 }
1009
1010 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1011 {
1012         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1013         return 0;
1014 }
1015
1016 const struct inode_operations ecryptfs_symlink_iops = {
1017         .readlink = ecryptfs_readlink,
1018         .follow_link = ecryptfs_follow_link,
1019         .put_link = ecryptfs_put_link,
1020         .permission = ecryptfs_permission,
1021         .setattr = ecryptfs_setattr,
1022         .setxattr = ecryptfs_setxattr,
1023         .getxattr = ecryptfs_getxattr,
1024         .listxattr = ecryptfs_listxattr,
1025         .removexattr = ecryptfs_removexattr
1026 };
1027
1028 const struct inode_operations ecryptfs_dir_iops = {
1029         .create = ecryptfs_create,
1030         .lookup = ecryptfs_lookup,
1031         .link = ecryptfs_link,
1032         .unlink = ecryptfs_unlink,
1033         .symlink = ecryptfs_symlink,
1034         .mkdir = ecryptfs_mkdir,
1035         .rmdir = ecryptfs_rmdir,
1036         .mknod = ecryptfs_mknod,
1037         .rename = ecryptfs_rename,
1038         .permission = ecryptfs_permission,
1039         .setattr = ecryptfs_setattr,
1040         .setxattr = ecryptfs_setxattr,
1041         .getxattr = ecryptfs_getxattr,
1042         .listxattr = ecryptfs_listxattr,
1043         .removexattr = ecryptfs_removexattr
1044 };
1045
1046 const struct inode_operations ecryptfs_main_iops = {
1047         .permission = ecryptfs_permission,
1048         .setattr = ecryptfs_setattr,
1049         .setxattr = ecryptfs_setxattr,
1050         .getxattr = ecryptfs_getxattr,
1051         .listxattr = ecryptfs_listxattr,
1052         .removexattr = ecryptfs_removexattr
1053 };