SAFE public projects git trees. - safe/jmp/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 "ecryptfs_kernel.h"
  35
  36 static struct dentry *lock_parent(struct dentry *dentry)
  37 {
  38         struct dentry *dir;
  39
  40         dir = dget(dentry->d_parent);
  41         mutex_lock(&(dir->d_inode->i_mutex));
  42         return dir;
  43 }
  44
  45 static void unlock_parent(struct dentry *dentry)
  46 {
  47         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
  48         dput(dentry->d_parent);
  49 }
  50
  51 static void unlock_dir(struct dentry *dir)
  52 {
  53         mutex_unlock(&dir->d_inode->i_mutex);
  54         dput(dir);
  55 }
  56
  57 /**
  58  * ecryptfs_create_underlying_file
  59  * @lower_dir_inode: inode of the parent in the lower fs of the new file
  60  * @lower_dentry: New file's dentry in the lower fs
  61  * @ecryptfs_dentry: New file's dentry in ecryptfs
  62  * @mode: The mode of the new file
  63  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  64  *
  65  * Creates the file in the lower file system.
  66  *
  67  * Returns zero on success; non-zero on error condition
  68  */
  69 static int
  70 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
  71                                 struct dentry *dentry, int mode,
  72                                 struct nameidata *nd)
  73 {
  74         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  75         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  76         struct dentry *dentry_save;
  77         struct vfsmount *vfsmount_save;
  78         int rc;
  79
  80         dentry_save = nd->dentry;
  81         vfsmount_save = nd->mnt;
  82         nd->dentry = lower_dentry;
  83         nd->mnt = lower_mnt;
  84         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
  85         nd->dentry = dentry_save;
  86         nd->mnt = vfsmount_save;
  87         return rc;
  88 }
  89
  90 /**
  91  * ecryptfs_do_create
  92  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
  93  * @ecryptfs_dentry: New file's dentry in ecryptfs
  94  * @mode: The mode of the new file
  95  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  96  *
  97  * Creates the underlying file and the eCryptfs inode which will link to
  98  * it. It will also update the eCryptfs directory inode to mimic the
  99  * stat of the lower directory inode.
 100  *
 101  * Returns zero on success; non-zero on error condition
 102  */
 103 static int
 104 ecryptfs_do_create(struct inode *directory_inode,
 105                    struct dentry *ecryptfs_dentry, int mode,
 106                    struct nameidata *nd)
 107 {
 108         int rc;
 109         struct dentry *lower_dentry;
 110         struct dentry *lower_dir_dentry;
 111
 112         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 113         lower_dir_dentry = lock_parent(lower_dentry);
 114         if (unlikely(IS_ERR(lower_dir_dentry))) {
 115                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 116                                 "dentry\n");
 117                 rc = PTR_ERR(lower_dir_dentry);
 118                 goto out;
 119         }
 120         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 121                                              ecryptfs_dentry, mode, nd);
 122         if (unlikely(rc)) {
 123                 ecryptfs_printk(KERN_ERR,
 124                                 "Failure to create underlying file\n");
 125                 goto out_lock;
 126         }
 127         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 128                                 directory_inode->i_sb, 0);
 129         if (rc) {
 130                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 131                 goto out_lock;
 132         }
 133         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
 134         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
 135 out_lock:
 136         unlock_dir(lower_dir_dentry);
 137 out:
 138         return rc;
 139 }
 140
 141 /**
 142  * grow_file
 143  * @ecryptfs_dentry: the ecryptfs dentry
 144  * @lower_file: The lower file
 145  * @inode: The ecryptfs inode
 146  * @lower_inode: The lower inode
 147  *
 148  * This is the code which will grow the file to its correct size.
 149  */
 150 static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
 151                      struct inode *inode, struct inode *lower_inode)
 152 {
 153         int rc = 0;
 154         struct file fake_file;
 155         struct ecryptfs_file_info tmp_file_info;
 156
 157         memset(&fake_file, 0, sizeof(fake_file));
 158         fake_file.f_path.dentry = ecryptfs_dentry;
 159         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 160         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 161         ecryptfs_set_file_lower(&fake_file, lower_file);
 162         rc = ecryptfs_fill_zeros(&fake_file, 1);
 163         if (rc) {
 164                 ECRYPTFS_SET_FLAG(
 165                         ecryptfs_inode_to_private(inode)->crypt_stat.flags,
 166                         ECRYPTFS_SECURITY_WARNING);
 167                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
 168                                 "in file; rc = [%d]\n", rc);
 169                 goto out;
 170         }
 171         i_size_write(inode, 0);
 172         ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode, inode,
 173                                               ecryptfs_dentry,
 174                                               ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 175         ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
 176                           ECRYPTFS_NEW_FILE);
 177 out:
 178         return rc;
 179 }
 180
 181 /**
 182  * ecryptfs_initialize_file
 183  *
 184  * Cause the file to be changed from a basic empty file to an ecryptfs
 185  * file with a header and first data page.
 186  *
 187  * Returns zero on success
 188  */
 189 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 190 {
 191         int rc = 0;
 192         int lower_flags;
 193         struct ecryptfs_crypt_stat *crypt_stat;
 194         struct dentry *lower_dentry;
 195         struct file *lower_file;
 196         struct inode *inode, *lower_inode;
 197         struct vfsmount *lower_mnt;
 198
 199         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 200         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
 201                         lower_dentry->d_name.name);
 202         inode = ecryptfs_dentry->d_inode;
 203         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 204         lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
 205 #if BITS_PER_LONG != 32
 206         lower_flags |= O_LARGEFILE;
 207 #endif
 208         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 209         /* Corresponding fput() at end of this function */
 210         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 211                                            lower_flags))) {
 212                 ecryptfs_printk(KERN_ERR,
 213                                 "Error opening dentry; rc = [%i]\n", rc);
 214                 goto out;
 215         }
 216         lower_inode = lower_dentry->d_inode;
 217         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 218                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 219                 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
 220                 goto out_fput;
 221         }
 222         ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
 223         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 224         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 225         if (rc) {
 226                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
 227                                 "context\n");
 228                 goto out_fput;
 229         }
 230         rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
 231         if (rc) {
 232                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
 233                 goto out_fput;
 234         }
 235         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
 236 out_fput:
 237         if ((rc = ecryptfs_close_lower_file(lower_file)))
 238                 printk(KERN_ERR "Error closing lower_file\n");
 239 out:
 240         return rc;
 241 }
 242
 243 /**
 244  * ecryptfs_create
 245  * @dir: The inode of the directory in which to create the file.
 246  * @dentry: The eCryptfs dentry
 247  * @mode: The mode of the new file.
 248  * @nd: nameidata
 249  *
 250  * Creates a new file.
 251  *
 252  * Returns zero on success; non-zero on error condition
 253  */
 254 static int
 255 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 256                 int mode, struct nameidata *nd)
 257 {
 258         int rc;
 259
 260         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 261         if (unlikely(rc)) {
 262                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 263                                 "lower filesystem\n");
 264                 goto out;
 265         }
 266         /* At this point, a file exists on "disk"; we need to make sure
 267          * that this on disk file is prepared to be an ecryptfs file */
 268         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 269 out:
 270         return rc;
 271 }
 272
 273 /**
 274  * ecryptfs_lookup
 275  * @dir: inode
 276  * @dentry: The dentry
 277  * @nd: nameidata, may be NULL
 278  *
 279  * Find a file on disk. If the file does not exist, then we'll add it to the
 280  * dentry cache and continue on to read it from the disk.
 281  */
 282 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 283                                       struct nameidata *nd)
 284 {
 285         int rc = 0;
 286         struct dentry *lower_dir_dentry;
 287         struct dentry *lower_dentry;
 288         struct vfsmount *lower_mnt;
 289         char *encoded_name;
 290         unsigned int encoded_namelen;
 291         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 292         char *page_virt = NULL;
 293         struct inode *lower_inode;
 294         u64 file_size;
 295
 296         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 297         dentry->d_op = &ecryptfs_dops;
 298         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 299             || (dentry->d_name.len == 2
 300                 && !strcmp(dentry->d_name.name, ".."))) {
 301                 d_drop(dentry);
 302                 goto out;
 303         }
 304         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 305                                                    dentry->d_name.name,
 306                                                    dentry->d_name.len,
 307                                                    &encoded_name);
 308         if (encoded_namelen < 0) {
 309                 rc = encoded_namelen;
 310                 d_drop(dentry);
 311                 goto out;
 312         }
 313         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 314                         "= [%d]\n", encoded_name, encoded_namelen);
 315         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 316                                       encoded_namelen - 1);
 317         kfree(encoded_name);
 318         if (IS_ERR(lower_dentry)) {
 319                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 320                 rc = PTR_ERR(lower_dentry);
 321                 d_drop(dentry);
 322                 goto out;
 323         }
 324         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 325         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 326                 "d_name.name = [%s]\n", lower_dentry,
 327                 lower_dentry->d_name.name);
 328         lower_inode = lower_dentry->d_inode;
 329         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 330         BUG_ON(!atomic_read(&lower_dentry->d_count));
 331         ecryptfs_set_dentry_private(dentry,
 332                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 333                                                      GFP_KERNEL));
 334         if (!ecryptfs_dentry_to_private(dentry)) {
 335                 rc = -ENOMEM;
 336                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 337                                 "to allocate ecryptfs_dentry_info struct\n");
 338                 goto out_dput;
 339         }
 340         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 341         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 342         if (!lower_dentry->d_inode) {
 343                 /* We want to add because we couldn't find in lower */
 344                 d_add(dentry, NULL);
 345                 goto out;
 346         }
 347         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 348         if (rc) {
 349                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 350                 goto out_dput;
 351         }
 352         if (S_ISDIR(lower_inode->i_mode)) {
 353                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 354                 goto out;
 355         }
 356         if (S_ISLNK(lower_inode->i_mode)) {
 357                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 358                 goto out;
 359         }
 360         if (!nd) {
 361                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 362                                 "as we *think* we are about to unlink\n");
 363                 goto out;
 364         }
 365         /* Released in this function */
 366         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 367                                       GFP_USER);
 368         if (!page_virt) {
 369                 rc = -ENOMEM;
 370                 ecryptfs_printk(KERN_ERR,
 371                                 "Cannot ecryptfs_kmalloc a page\n");
 372                 goto out_dput;
 373         }
 374         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 375         if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
 376                 ecryptfs_set_default_sizes(crypt_stat);
 377         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
 378                                                       nd->mnt);
 379         if (rc) {
 380                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 381                 if (rc) {
 382                         printk(KERN_DEBUG "Valid metadata not found in header "
 383                                "region or xattr region; treating file as "
 384                                "unencrypted\n");
 385                         rc = 0;
 386                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 387                         goto out;
 388                 }
 389                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 390         }
 391         memcpy(&file_size, page_virt, sizeof(file_size));
 392         file_size = be64_to_cpu(file_size);
 393         i_size_write(dentry->d_inode, (loff_t)file_size);
 394         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 395         goto out;
 396
 397 out_dput:
 398         dput(lower_dentry);
 399         d_drop(dentry);
 400 out:
 401         return ERR_PTR(rc);
 402 }
 403
 404 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 405                          struct dentry *new_dentry)
 406 {
 407         struct dentry *lower_old_dentry;
 408         struct dentry *lower_new_dentry;
 409         struct dentry *lower_dir_dentry;
 410         u64 file_size_save;
 411         int rc;
 412
 413         file_size_save = i_size_read(old_dentry->d_inode);
 414         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 415         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 416         dget(lower_old_dentry);
 417         dget(lower_new_dentry);
 418         lower_dir_dentry = lock_parent(lower_new_dentry);
 419         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 420                       lower_new_dentry);
 421         if (rc || !lower_new_dentry->d_inode)
 422                 goto out_lock;
 423         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 424         if (rc)
 425                 goto out_lock;
 426         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 427         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 428         old_dentry->d_inode->i_nlink =
 429                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 430         i_size_write(new_dentry->d_inode, file_size_save);
 431 out_lock:
 432         unlock_dir(lower_dir_dentry);
 433         dput(lower_new_dentry);
 434         dput(lower_old_dentry);
 435         d_drop(lower_old_dentry);
 436         d_drop(new_dentry);
 437         d_drop(old_dentry);
 438         return rc;
 439 }
 440
 441 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 442 {
 443         int rc = 0;
 444         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 445         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 446
 447         lock_parent(lower_dentry);
 448         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 449         if (rc) {
 450                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 451                 goto out_unlock;
 452         }
 453         fsstack_copy_attr_times(dir, lower_dir_inode);
 454         dentry->d_inode->i_nlink =
 455                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 456         dentry->d_inode->i_ctime = dir->i_ctime;
 457 out_unlock:
 458         unlock_parent(lower_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         umode_t mode;
 469         char *encoded_symname;
 470         unsigned int encoded_symlen;
 471         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 472
 473         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 474         dget(lower_dentry);
 475         lower_dir_dentry = lock_parent(lower_dentry);
 476         mode = S_IALLUGO;
 477         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 478                                                   strlen(symname),
 479                                                   &encoded_symname);
 480         if (encoded_symlen < 0) {
 481                 rc = encoded_symlen;
 482                 goto out_lock;
 483         }
 484         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 485                          encoded_symname, mode);
 486         kfree(encoded_symname);
 487         if (rc || !lower_dentry->d_inode)
 488                 goto out_lock;
 489         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 490         if (rc)
 491                 goto out_lock;
 492         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 493         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 494 out_lock:
 495         unlock_dir(lower_dir_dentry);
 496         dput(lower_dentry);
 497         if (!dentry->d_inode)
 498                 d_drop(dentry);
 499         return rc;
 500 }
 501
 502 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 503 {
 504         int rc;
 505         struct dentry *lower_dentry;
 506         struct dentry *lower_dir_dentry;
 507
 508         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 509         lower_dir_dentry = lock_parent(lower_dentry);
 510         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 511         if (rc || !lower_dentry->d_inode)
 512                 goto out;
 513         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 514         if (rc)
 515                 goto out;
 516         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 517         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 518         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 519 out:
 520         unlock_dir(lower_dir_dentry);
 521         if (!dentry->d_inode)
 522                 d_drop(dentry);
 523         return rc;
 524 }
 525
 526 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 527 {
 528         struct dentry *lower_dentry;
 529         struct dentry *lower_dir_dentry;
 530         int rc;
 531
 532         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 533         dget(dentry);
 534         lower_dir_dentry = lock_parent(lower_dentry);
 535         dget(lower_dentry);
 536         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 537         dput(lower_dentry);
 538         if (!rc)
 539                 d_delete(lower_dentry);
 540         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 541         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 542         unlock_dir(lower_dir_dentry);
 543         if (!rc)
 544                 d_drop(dentry);
 545         dput(dentry);
 546         return rc;
 547 }
 548
 549 static int
 550 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 551 {
 552         int rc;
 553         struct dentry *lower_dentry;
 554         struct dentry *lower_dir_dentry;
 555
 556         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 557         lower_dir_dentry = lock_parent(lower_dentry);
 558         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 559         if (rc || !lower_dentry->d_inode)
 560                 goto out;
 561         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 562         if (rc)
 563                 goto out;
 564         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 565         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 566 out:
 567         unlock_dir(lower_dir_dentry);
 568         if (!dentry->d_inode)
 569                 d_drop(dentry);
 570         return rc;
 571 }
 572
 573 static int
 574 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 575                 struct inode *new_dir, struct dentry *new_dentry)
 576 {
 577         int rc;
 578         struct dentry *lower_old_dentry;
 579         struct dentry *lower_new_dentry;
 580         struct dentry *lower_old_dir_dentry;
 581         struct dentry *lower_new_dir_dentry;
 582
 583         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 584         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 585         dget(lower_old_dentry);
 586         dget(lower_new_dentry);
 587         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 588         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 589         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 590         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 591                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 592         if (rc)
 593                 goto out_lock;
 594         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 595         if (new_dir != old_dir)
 596                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 597 out_lock:
 598         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 599         dput(lower_new_dentry->d_parent);
 600         dput(lower_old_dentry->d_parent);
 601         dput(lower_new_dentry);
 602         dput(lower_old_dentry);
 603         return rc;
 604 }
 605
 606 static int
 607 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 608 {
 609         int rc;
 610         struct dentry *lower_dentry;
 611         char *decoded_name;
 612         char *lower_buf;
 613         mm_segment_t old_fs;
 614         struct ecryptfs_crypt_stat *crypt_stat;
 615
 616         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 617         if (!lower_dentry->d_inode->i_op ||
 618             !lower_dentry->d_inode->i_op->readlink) {
 619                 rc = -EINVAL;
 620                 goto out;
 621         }
 622         /* Released in this function */
 623         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 624         if (lower_buf == NULL) {
 625                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 626                 rc = -ENOMEM;
 627                 goto out;
 628         }
 629         old_fs = get_fs();
 630         set_fs(get_ds());
 631         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 632                         "lower_dentry->d_name.name = [%s]\n",
 633                         lower_dentry->d_name.name);
 634         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 635                                                    (char __user *)lower_buf,
 636                                                    bufsiz);
 637         set_fs(old_fs);
 638         if (rc >= 0) {
 639                 crypt_stat = NULL;
 640                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 641                                               &decoded_name);
 642                 if (rc == -ENOMEM)
 643                         goto out_free_lower_buf;
 644                 if (rc > 0) {
 645                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 646                                         "to userspace: [%*s]\n", rc,
 647                                         decoded_name);
 648                         if (copy_to_user(buf, decoded_name, rc))
 649                                 rc = -EFAULT;
 650                 }
 651                 kfree(decoded_name);
 652                 fsstack_copy_attr_atime(dentry->d_inode,
 653                                         lower_dentry->d_inode);
 654         }
 655 out_free_lower_buf:
 656         kfree(lower_buf);
 657 out:
 658         return rc;
 659 }
 660
 661 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 662 {
 663         char *buf;
 664         int len = PAGE_SIZE, rc;
 665         mm_segment_t old_fs;
 666
 667         /* Released in ecryptfs_put_link(); only release here on error */
 668         buf = kmalloc(len, GFP_KERNEL);
 669         if (!buf) {
 670                 rc = -ENOMEM;
 671                 goto out;
 672         }
 673         old_fs = get_fs();
 674         set_fs(get_ds());
 675         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 676                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 677         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 678         buf[rc] = '\0';
 679         set_fs(old_fs);
 680         if (rc < 0)
 681                 goto out_free;
 682         rc = 0;
 683         nd_set_link(nd, buf);
 684         goto out;
 685 out_free:
 686         kfree(buf);
 687 out:
 688         return ERR_PTR(rc);
 689 }
 690
 691 static void
 692 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 693 {
 694         /* Free the char* */
 695         kfree(nd_get_link(nd));
 696 }
 697
 698 /**
 699  * upper_size_to_lower_size
 700  * @crypt_stat: Crypt_stat associated with file
 701  * @upper_size: Size of the upper file
 702  *
 703  * Calculate the requried size of the lower file based on the
 704  * specified size of the upper file. This calculation is based on the
 705  * number of headers in the underlying file and the extent size.
 706  *
 707  * Returns Calculated size of the lower file.
 708  */
 709 static loff_t
 710 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 711                          loff_t upper_size)
 712 {
 713         loff_t lower_size;
 714
 715         lower_size = ( crypt_stat->header_extent_size
 716                        * crypt_stat->num_header_extents_at_front );
 717         if (upper_size != 0) {
 718                 loff_t num_extents;
 719
 720                 num_extents = upper_size >> crypt_stat->extent_shift;
 721                 if (upper_size & ~crypt_stat->extent_mask)
 722                         num_extents++;
 723                 lower_size += (num_extents * crypt_stat->extent_size);
 724         }
 725         return lower_size;
 726 }
 727
 728 /**
 729  * ecryptfs_truncate
 730  * @dentry: The ecryptfs layer dentry
 731  * @new_length: The length to expand the file to
 732  *
 733  * Function to handle truncations modifying the size of the file. Note
 734  * that the file sizes are interpolated. When expanding, we are simply
 735  * writing strings of 0's out. When truncating, we need to modify the
 736  * underlying file size according to the page index interpolations.
 737  *
 738  * Returns zero on success; non-zero otherwise
 739  */
 740 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 741 {
 742         int rc = 0;
 743         struct inode *inode = dentry->d_inode;
 744         struct dentry *lower_dentry;
 745         struct vfsmount *lower_mnt;
 746         struct file fake_ecryptfs_file, *lower_file = NULL;
 747         struct ecryptfs_crypt_stat *crypt_stat;
 748         loff_t i_size = i_size_read(inode);
 749         loff_t lower_size_before_truncate;
 750         loff_t lower_size_after_truncate;
 751
 752         if (unlikely((new_length == i_size)))
 753                 goto out;
 754         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 755         /* Set up a fake ecryptfs file, this is used to interface with
 756          * the file in the underlying filesystem so that the
 757          * truncation has an effect there as well. */
 758         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 759         fake_ecryptfs_file.f_path.dentry = dentry;
 760         /* Released at out_free: label */
 761         ecryptfs_set_file_private(&fake_ecryptfs_file,
 762                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 763                                                    GFP_KERNEL));
 764         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 765                 rc = -ENOMEM;
 766                 goto out;
 767         }
 768         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 769         /* This dget & mntget is released through fput at out_fput: */
 770         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 771         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 772                                            O_RDWR))) {
 773                 ecryptfs_printk(KERN_ERR,
 774                                 "Error opening dentry; rc = [%i]\n", rc);
 775                 goto out_free;
 776         }
 777         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 778         /* Switch on growing or shrinking file */
 779         if (new_length > i_size) {
 780                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 781                 if (rc) {
 782                         ecryptfs_printk(KERN_ERR,
 783                                         "Problem with fill_zeros\n");
 784                         goto out_fput;
 785                 }
 786                 i_size_write(inode, new_length);
 787                 rc = ecryptfs_write_inode_size_to_metadata(
 788                         lower_file, lower_dentry->d_inode, inode, dentry,
 789                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 790                 if (rc) {
 791                         printk(KERN_ERR "Problem with "
 792                                "ecryptfs_write_inode_size_to_metadata; "
 793                                "rc = [%d]\n", rc);
 794                         goto out_fput;
 795                 }
 796         } else { /* new_length < i_size_read(inode) */
 797                 vmtruncate(inode, new_length);
 798                 rc = ecryptfs_write_inode_size_to_metadata(
 799                         lower_file, lower_dentry->d_inode, inode, dentry,
 800                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 801                 if (rc) {
 802                         printk(KERN_ERR "Problem with "
 803                                "ecryptfs_write_inode_size_to_metadata; "
 804                                "rc = [%d]\n", rc);
 805                         goto out_fput;
 806                 }
 807                 /* We are reducing the size of the ecryptfs file, and need to
 808                  * know if we need to reduce the size of the lower file. */
 809                 lower_size_before_truncate =
 810                     upper_size_to_lower_size(crypt_stat, i_size);
 811                 lower_size_after_truncate =
 812                     upper_size_to_lower_size(crypt_stat, new_length);
 813                 if (lower_size_after_truncate < lower_size_before_truncate)
 814                         vmtruncate(lower_dentry->d_inode,
 815                                    lower_size_after_truncate);
 816         }
 817         /* Update the access times */
 818         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 819                 = CURRENT_TIME;
 820         mark_inode_dirty_sync(inode);
 821 out_fput:
 822         if ((rc = ecryptfs_close_lower_file(lower_file)))
 823                 printk(KERN_ERR "Error closing lower_file\n");
 824 out_free:
 825         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 826                 kmem_cache_free(ecryptfs_file_info_cache,
 827                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 828 out:
 829         return rc;
 830 }
 831
 832 static int
 833 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 834 {
 835         int rc;
 836
 837         if (nd) {
 838                 struct vfsmount *vfsmnt_save = nd->mnt;
 839                 struct dentry *dentry_save = nd->dentry;
 840
 841                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 842                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 843                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 844                 nd->mnt = vfsmnt_save;
 845                 nd->dentry = dentry_save;
 846         } else
 847                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 848         return rc;
 849 }
 850
 851 /**
 852  * ecryptfs_setattr
 853  * @dentry: dentry handle to the inode to modify
 854  * @ia: Structure with flags of what to change and values
 855  *
 856  * Updates the metadata of an inode. If the update is to the size
 857  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 858  * of both the ecryptfs inode and the lower inode.
 859  *
 860  * All other metadata changes will be passed right to the lower filesystem,
 861  * and we will just update our inode to look like the lower.
 862  */
 863 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 864 {
 865         int rc = 0;
 866         struct dentry *lower_dentry;
 867         struct inode *inode;
 868         struct inode *lower_inode;
 869         struct ecryptfs_crypt_stat *crypt_stat;
 870
 871         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 872         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 873         inode = dentry->d_inode;
 874         lower_inode = ecryptfs_inode_to_lower(inode);
 875         if (ia->ia_valid & ATTR_SIZE) {
 876                 ecryptfs_printk(KERN_DEBUG,
 877                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 878                                 ia->ia_valid, ATTR_SIZE);
 879                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 880                 /* ecryptfs_truncate handles resizing of the lower file */
 881                 ia->ia_valid &= ~ATTR_SIZE;
 882                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 883                                 ia->ia_valid);
 884                 if (rc < 0)
 885                         goto out;
 886         }
 887         rc = notify_change(lower_dentry, ia);
 888 out:
 889         fsstack_copy_attr_all(inode, lower_inode, NULL);
 890         return rc;
 891 }
 892
 893 int
 894 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 895                   size_t size, int flags)
 896 {
 897         int rc = 0;
 898         struct dentry *lower_dentry;
 899
 900         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 901         if (!lower_dentry->d_inode->i_op->setxattr) {
 902                 rc = -ENOSYS;
 903                 goto out;
 904         }
 905         mutex_lock(&lower_dentry->d_inode->i_mutex);
 906         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 907                                                    size, flags);
 908         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 909 out:
 910         return rc;
 911 }
 912
 913 ssize_t
 914 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 915                   size_t size)
 916 {
 917         int rc = 0;
 918         struct dentry *lower_dentry;
 919
 920         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 921         if (!lower_dentry->d_inode->i_op->getxattr) {
 922                 rc = -ENOSYS;
 923                 goto out;
 924         }
 925         mutex_lock(&lower_dentry->d_inode->i_mutex);
 926         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 927                                                    size);
 928         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 929 out:
 930         return rc;
 931 }
 932
 933 static ssize_t
 934 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 935 {
 936         int rc = 0;
 937         struct dentry *lower_dentry;
 938
 939         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 940         if (!lower_dentry->d_inode->i_op->listxattr) {
 941                 rc = -ENOSYS;
 942                 goto out;
 943         }
 944         mutex_lock(&lower_dentry->d_inode->i_mutex);
 945         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
 946         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 947 out:
 948         return rc;
 949 }
 950
 951 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
 952 {
 953         int rc = 0;
 954         struct dentry *lower_dentry;
 955
 956         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 957         if (!lower_dentry->d_inode->i_op->removexattr) {
 958                 rc = -ENOSYS;
 959                 goto out;
 960         }
 961         mutex_lock(&lower_dentry->d_inode->i_mutex);
 962         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
 963         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 964 out:
 965         return rc;
 966 }
 967
 968 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
 969 {
 970         if ((ecryptfs_inode_to_lower(inode)
 971              == (struct inode *)candidate_lower_inode))
 972                 return 1;
 973         else
 974                 return 0;
 975 }
 976
 977 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
 978 {
 979         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
 980         return 0;
 981 }
 982
 983 struct inode_operations ecryptfs_symlink_iops = {
 984         .readlink = ecryptfs_readlink,
 985         .follow_link = ecryptfs_follow_link,
 986         .put_link = ecryptfs_put_link,
 987         .permission = ecryptfs_permission,
 988         .setattr = ecryptfs_setattr,
 989         .setxattr = ecryptfs_setxattr,
 990         .getxattr = ecryptfs_getxattr,
 991         .listxattr = ecryptfs_listxattr,
 992         .removexattr = ecryptfs_removexattr
 993 };
 994
 995 struct inode_operations ecryptfs_dir_iops = {
 996         .create = ecryptfs_create,
 997         .lookup = ecryptfs_lookup,
 998         .link = ecryptfs_link,
 999         .unlink = ecryptfs_unlink,
1000         .symlink = ecryptfs_symlink,
1001         .mkdir = ecryptfs_mkdir,
1002         .rmdir = ecryptfs_rmdir,
1003         .mknod = ecryptfs_mknod,
1004         .rename = ecryptfs_rename,
1005         .permission = ecryptfs_permission,
1006         .setattr = ecryptfs_setattr,
1007         .setxattr = ecryptfs_setxattr,
1008         .getxattr = ecryptfs_getxattr,
1009         .listxattr = ecryptfs_listxattr,
1010         .removexattr = ecryptfs_removexattr
1011 };
1012
1013 struct inode_operations ecryptfs_main_iops = {
1014         .permission = ecryptfs_permission,
1015         .setattr = ecryptfs_setattr,
1016         .setxattr = ecryptfs_setxattr,
1017         .getxattr = ecryptfs_getxattr,
1018         .listxattr = ecryptfs_listxattr,
1019         .removexattr = ecryptfs_removexattr
1020 };