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) 2004-2006 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_header(lower_file, lower_inode, inode);
 173         ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
 174                           ECRYPTFS_NEW_FILE);
 175 out:
 176         return rc;
 177 }
 178
 179 /**
 180  * ecryptfs_initialize_file
 181  *
 182  * Cause the file to be changed from a basic empty file to an ecryptfs
 183  * file with a header and first data page.
 184  *
 185  * Returns zero on success
 186  */
 187 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 188 {
 189         int rc = 0;
 190         int lower_flags;
 191         struct ecryptfs_crypt_stat *crypt_stat;
 192         struct dentry *lower_dentry;
 193         struct file *lower_file;
 194         struct inode *inode, *lower_inode;
 195         struct vfsmount *lower_mnt;
 196
 197         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 198         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
 199                         lower_dentry->d_name.name);
 200         inode = ecryptfs_dentry->d_inode;
 201         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 202         lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
 203 #if BITS_PER_LONG != 32
 204         lower_flags |= O_LARGEFILE;
 205 #endif
 206         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 207         /* Corresponding fput() at end of this function */
 208         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 209                                            lower_flags))) {
 210                 ecryptfs_printk(KERN_ERR,
 211                                 "Error opening dentry; rc = [%i]\n", rc);
 212                 goto out;
 213         }
 214         lower_inode = lower_dentry->d_inode;
 215         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 216                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 217                 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
 218                 goto out_fput;
 219         }
 220         ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
 221         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 222         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 223         if (rc) {
 224                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
 225                                 "context\n");
 226                 goto out_fput;
 227         }
 228         rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
 229         if (rc) {
 230                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
 231                 goto out_fput;
 232         }
 233         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
 234 out_fput:
 235         if ((rc = ecryptfs_close_lower_file(lower_file)))
 236                 printk(KERN_ERR "Error closing lower_file\n");
 237 out:
 238         return rc;
 239 }
 240
 241 /**
 242  * ecryptfs_create
 243  * @dir: The inode of the directory in which to create the file.
 244  * @dentry: The eCryptfs dentry
 245  * @mode: The mode of the new file.
 246  * @nd: nameidata
 247  *
 248  * Creates a new file.
 249  *
 250  * Returns zero on success; non-zero on error condition
 251  */
 252 static int
 253 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 254                 int mode, struct nameidata *nd)
 255 {
 256         int rc;
 257
 258         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 259         if (unlikely(rc)) {
 260                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 261                                 "lower filesystem\n");
 262                 goto out;
 263         }
 264         /* At this point, a file exists on "disk"; we need to make sure
 265          * that this on disk file is prepared to be an ecryptfs file */
 266         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 267 out:
 268         return rc;
 269 }
 270
 271 /**
 272  * ecryptfs_lookup
 273  * @dir: inode
 274  * @dentry: The dentry
 275  * @nd: nameidata, may be NULL
 276  *
 277  * Find a file on disk. If the file does not exist, then we'll add it to the
 278  * dentry cache and continue on to read it from the disk.
 279  */
 280 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 281                                       struct nameidata *nd)
 282 {
 283         int rc = 0;
 284         struct dentry *lower_dir_dentry;
 285         struct dentry *lower_dentry;
 286         struct vfsmount *lower_mnt;
 287         char *encoded_name;
 288         unsigned int encoded_namelen;
 289         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 290         char *page_virt = NULL;
 291         struct inode *lower_inode;
 292         u64 file_size;
 293
 294         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 295         dentry->d_op = &ecryptfs_dops;
 296         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 297             || (dentry->d_name.len == 2
 298                 && !strcmp(dentry->d_name.name, ".."))) {
 299                 d_drop(dentry);
 300                 goto out;
 301         }
 302         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 303                                                    dentry->d_name.name,
 304                                                    dentry->d_name.len,
 305                                                    &encoded_name);
 306         if (encoded_namelen < 0) {
 307                 rc = encoded_namelen;
 308                 d_drop(dentry);
 309                 goto out;
 310         }
 311         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 312                         "= [%d]\n", encoded_name, encoded_namelen);
 313         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 314                                       encoded_namelen - 1);
 315         kfree(encoded_name);
 316         if (IS_ERR(lower_dentry)) {
 317                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 318                 rc = PTR_ERR(lower_dentry);
 319                 d_drop(dentry);
 320                 goto out;
 321         }
 322         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 323         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 324                 "d_name.name = [%s]\n", lower_dentry,
 325                 lower_dentry->d_name.name);
 326         lower_inode = lower_dentry->d_inode;
 327         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 328         BUG_ON(!atomic_read(&lower_dentry->d_count));
 329         ecryptfs_set_dentry_private(dentry,
 330                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 331                                                      GFP_KERNEL));
 332         if (!ecryptfs_dentry_to_private(dentry)) {
 333                 rc = -ENOMEM;
 334                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 335                                 "to allocate ecryptfs_dentry_info struct\n");
 336                 goto out_dput;
 337         }
 338         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 339         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 340         if (!lower_dentry->d_inode) {
 341                 /* We want to add because we couldn't find in lower */
 342                 d_add(dentry, NULL);
 343                 goto out;
 344         }
 345         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 346         if (rc) {
 347                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 348                 goto out_dput;
 349         }
 350         if (S_ISDIR(lower_inode->i_mode)) {
 351                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 352                 goto out;
 353         }
 354         if (S_ISLNK(lower_inode->i_mode)) {
 355                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 356                 goto out;
 357         }
 358         if (!nd) {
 359                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 360                                 "as we *think* we are about to unlink\n");
 361                 goto out;
 362         }
 363         /* Released in this function */
 364         page_virt =
 365             (char *)kmem_cache_alloc(ecryptfs_header_cache_2,
 366                                      GFP_USER);
 367         if (!page_virt) {
 368                 rc = -ENOMEM;
 369                 ecryptfs_printk(KERN_ERR,
 370                                 "Cannot ecryptfs_kmalloc a page\n");
 371                 goto out_dput;
 372         }
 373         memset(page_virt, 0, PAGE_CACHE_SIZE);
 374         rc = ecryptfs_read_header_region(page_virt, lower_dentry, nd->mnt);
 375         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 376         if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
 377                 ecryptfs_set_default_sizes(crypt_stat);
 378         if (rc) {
 379                 rc = 0;
 380                 ecryptfs_printk(KERN_WARNING, "Error reading header region;"
 381                                 " assuming unencrypted\n");
 382         } else {
 383                 if (!contains_ecryptfs_marker(page_virt
 384                                               + ECRYPTFS_FILE_SIZE_BYTES)) {
 385                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 386                         goto out;
 387                 }
 388                 memcpy(&file_size, page_virt, sizeof(file_size));
 389                 file_size = be64_to_cpu(file_size);
 390                 i_size_write(dentry->d_inode, (loff_t)file_size);
 391         }
 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
 445         lock_parent(lower_dentry);
 446         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 447         if (rc) {
 448                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 449                 goto out_unlock;
 450         }
 451         fsstack_copy_attr_times(dir, lower_dir_inode);
 452         dentry->d_inode->i_nlink =
 453                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 454         dentry->d_inode->i_ctime = dir->i_ctime;
 455 out_unlock:
 456         unlock_parent(lower_dentry);
 457         return rc;
 458 }
 459
 460 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 461                             const char *symname)
 462 {
 463         int rc;
 464         struct dentry *lower_dentry;
 465         struct dentry *lower_dir_dentry;
 466         umode_t mode;
 467         char *encoded_symname;
 468         unsigned int encoded_symlen;
 469         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 470
 471         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 472         dget(lower_dentry);
 473         lower_dir_dentry = lock_parent(lower_dentry);
 474         mode = S_IALLUGO;
 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, mode);
 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 requried 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->header_extent_size
 714                        * crypt_stat->num_header_extents_at_front );
 715         if (upper_size != 0) {
 716                 loff_t num_extents;
 717
 718                 num_extents = upper_size >> crypt_stat->extent_shift;
 719                 if (upper_size & ~crypt_stat->extent_mask)
 720                         num_extents++;
 721                 lower_size += (num_extents * crypt_stat->extent_size);
 722         }
 723         return lower_size;
 724 }
 725
 726 /**
 727  * ecryptfs_truncate
 728  * @dentry: The ecryptfs layer dentry
 729  * @new_length: The length to expand the file to
 730  *
 731  * Function to handle truncations modifying the size of the file. Note
 732  * that the file sizes are interpolated. When expanding, we are simply
 733  * writing strings of 0's out. When truncating, we need to modify the
 734  * underlying file size according to the page index interpolations.
 735  *
 736  * Returns zero on success; non-zero otherwise
 737  */
 738 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 739 {
 740         int rc = 0;
 741         struct inode *inode = dentry->d_inode;
 742         struct dentry *lower_dentry;
 743         struct vfsmount *lower_mnt;
 744         struct file fake_ecryptfs_file, *lower_file = NULL;
 745         struct ecryptfs_crypt_stat *crypt_stat;
 746         loff_t i_size = i_size_read(inode);
 747         loff_t lower_size_before_truncate;
 748         loff_t lower_size_after_truncate;
 749
 750         if (unlikely((new_length == i_size)))
 751                 goto out;
 752         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 753         /* Set up a fake ecryptfs file, this is used to interface with
 754          * the file in the underlying filesystem so that the
 755          * truncation has an effect there as well. */
 756         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 757         fake_ecryptfs_file.f_path.dentry = dentry;
 758         /* Released at out_free: label */
 759         ecryptfs_set_file_private(&fake_ecryptfs_file,
 760                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 761                                                    GFP_KERNEL));
 762         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 763                 rc = -ENOMEM;
 764                 goto out;
 765         }
 766         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 767         /* This dget & mntget is released through fput at out_fput: */
 768         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 769         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 770                                            O_RDWR))) {
 771                 ecryptfs_printk(KERN_ERR,
 772                                 "Error opening dentry; rc = [%i]\n", rc);
 773                 goto out_free;
 774         }
 775         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 776         /* Switch on growing or shrinking file */
 777         if (new_length > i_size) {
 778                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 779                 if (rc) {
 780                         ecryptfs_printk(KERN_ERR,
 781                                         "Problem with fill_zeros\n");
 782                         goto out_fput;
 783                 }
 784                 i_size_write(inode, new_length);
 785                 rc = ecryptfs_write_inode_size_to_header(lower_file,
 786                                                          lower_dentry->d_inode,
 787                                                          inode);
 788                 if (rc) {
 789                         ecryptfs_printk(KERN_ERR,
 790                                         "Problem with ecryptfs_write"
 791                                         "_inode_size\n");
 792                         goto out_fput;
 793                 }
 794         } else { /* new_length < i_size_read(inode) */
 795                 vmtruncate(inode, new_length);
 796                 ecryptfs_write_inode_size_to_header(lower_file,
 797                                                     lower_dentry->d_inode,
 798                                                     inode);
 799                 /* We are reducing the size of the ecryptfs file, and need to
 800                  * know if we need to reduce the size of the lower file. */
 801                 lower_size_before_truncate =
 802                     upper_size_to_lower_size(crypt_stat, i_size);
 803                 lower_size_after_truncate =
 804                     upper_size_to_lower_size(crypt_stat, new_length);
 805                 if (lower_size_after_truncate < lower_size_before_truncate)
 806                         vmtruncate(lower_dentry->d_inode,
 807                                    lower_size_after_truncate);
 808         }
 809         /* Update the access times */
 810         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 811                 = CURRENT_TIME;
 812         mark_inode_dirty_sync(inode);
 813 out_fput:
 814         if ((rc = ecryptfs_close_lower_file(lower_file)))
 815                 printk(KERN_ERR "Error closing lower_file\n");
 816 out_free:
 817         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 818                 kmem_cache_free(ecryptfs_file_info_cache,
 819                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 820 out:
 821         return rc;
 822 }
 823
 824 static int
 825 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 826 {
 827         int rc;
 828
 829         if (nd) {
 830                 struct vfsmount *vfsmnt_save = nd->mnt;
 831                 struct dentry *dentry_save = nd->dentry;
 832
 833                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 834                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 835                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 836                 nd->mnt = vfsmnt_save;
 837                 nd->dentry = dentry_save;
 838         } else
 839                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 840         return rc;
 841 }
 842
 843 /**
 844  * ecryptfs_setattr
 845  * @dentry: dentry handle to the inode to modify
 846  * @ia: Structure with flags of what to change and values
 847  *
 848  * Updates the metadata of an inode. If the update is to the size
 849  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 850  * of both the ecryptfs inode and the lower inode.
 851  *
 852  * All other metadata changes will be passed right to the lower filesystem,
 853  * and we will just update our inode to look like the lower.
 854  */
 855 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 856 {
 857         int rc = 0;
 858         struct dentry *lower_dentry;
 859         struct inode *inode;
 860         struct inode *lower_inode;
 861         struct ecryptfs_crypt_stat *crypt_stat;
 862
 863         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 864         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 865         inode = dentry->d_inode;
 866         lower_inode = ecryptfs_inode_to_lower(inode);
 867         if (ia->ia_valid & ATTR_SIZE) {
 868                 ecryptfs_printk(KERN_DEBUG,
 869                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 870                                 ia->ia_valid, ATTR_SIZE);
 871                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 872                 /* ecryptfs_truncate handles resizing of the lower file */
 873                 ia->ia_valid &= ~ATTR_SIZE;
 874                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 875                                 ia->ia_valid);
 876                 if (rc < 0)
 877                         goto out;
 878         }
 879         rc = notify_change(lower_dentry, ia);
 880 out:
 881         fsstack_copy_attr_all(inode, lower_inode, NULL);
 882         return rc;
 883 }
 884
 885 static int
 886 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 887                   size_t size, int flags)
 888 {
 889         int rc = 0;
 890         struct dentry *lower_dentry;
 891
 892         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 893         if (!lower_dentry->d_inode->i_op->setxattr) {
 894                 rc = -ENOSYS;
 895                 goto out;
 896         }
 897         mutex_lock(&lower_dentry->d_inode->i_mutex);
 898         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 899                                                    size, flags);
 900         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 901 out:
 902         return rc;
 903 }
 904
 905 static ssize_t
 906 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 907                   size_t size)
 908 {
 909         int rc = 0;
 910         struct dentry *lower_dentry;
 911
 912         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 913         if (!lower_dentry->d_inode->i_op->getxattr) {
 914                 rc = -ENOSYS;
 915                 goto out;
 916         }
 917         mutex_lock(&lower_dentry->d_inode->i_mutex);
 918         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 919                                                    size);
 920         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 921 out:
 922         return rc;
 923 }
 924
 925 static ssize_t
 926 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 927 {
 928         int rc = 0;
 929         struct dentry *lower_dentry;
 930
 931         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 932         if (!lower_dentry->d_inode->i_op->listxattr) {
 933                 rc = -ENOSYS;
 934                 goto out;
 935         }
 936         mutex_lock(&lower_dentry->d_inode->i_mutex);
 937         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
 938         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 939 out:
 940         return rc;
 941 }
 942
 943 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
 944 {
 945         int rc = 0;
 946         struct dentry *lower_dentry;
 947
 948         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 949         if (!lower_dentry->d_inode->i_op->removexattr) {
 950                 rc = -ENOSYS;
 951                 goto out;
 952         }
 953         mutex_lock(&lower_dentry->d_inode->i_mutex);
 954         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
 955         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 956 out:
 957         return rc;
 958 }
 959
 960 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
 961 {
 962         if ((ecryptfs_inode_to_lower(inode)
 963              == (struct inode *)candidate_lower_inode))
 964                 return 1;
 965         else
 966                 return 0;
 967 }
 968
 969 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
 970 {
 971         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
 972         return 0;
 973 }
 974
 975 struct inode_operations ecryptfs_symlink_iops = {
 976         .readlink = ecryptfs_readlink,
 977         .follow_link = ecryptfs_follow_link,
 978         .put_link = ecryptfs_put_link,
 979         .permission = ecryptfs_permission,
 980         .setattr = ecryptfs_setattr,
 981         .setxattr = ecryptfs_setxattr,
 982         .getxattr = ecryptfs_getxattr,
 983         .listxattr = ecryptfs_listxattr,
 984         .removexattr = ecryptfs_removexattr
 985 };
 986
 987 struct inode_operations ecryptfs_dir_iops = {
 988         .create = ecryptfs_create,
 989         .lookup = ecryptfs_lookup,
 990         .link = ecryptfs_link,
 991         .unlink = ecryptfs_unlink,
 992         .symlink = ecryptfs_symlink,
 993         .mkdir = ecryptfs_mkdir,
 994         .rmdir = ecryptfs_rmdir,
 995         .mknod = ecryptfs_mknod,
 996         .rename = ecryptfs_rename,
 997         .permission = ecryptfs_permission,
 998         .setattr = ecryptfs_setattr,
 999         .setxattr = ecryptfs_setxattr,
1000         .getxattr = ecryptfs_getxattr,
1001         .listxattr = ecryptfs_listxattr,
1002         .removexattr = ecryptfs_removexattr
1003 };
1004
1005 struct inode_operations ecryptfs_main_iops = {
1006         .permission = ecryptfs_permission,
1007         .setattr = ecryptfs_setattr,
1008         .setxattr = ecryptfs_setxattr,
1009         .getxattr = ecryptfs_getxattr,
1010         .listxattr = ecryptfs_listxattr,
1011         .removexattr = ecryptfs_removexattr
1012 };