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 "ecryptfs_kernel.h"
  34
  35 static struct dentry *lock_parent(struct dentry *dentry)
  36 {
  37         struct dentry *dir;
  38
  39         dir = dget(dentry->d_parent);
  40         mutex_lock(&(dir->d_inode->i_mutex));
  41         return dir;
  42 }
  43
  44 static void unlock_parent(struct dentry *dentry)
  45 {
  46         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
  47         dput(dentry->d_parent);
  48 }
  49
  50 static void unlock_dir(struct dentry *dir)
  51 {
  52         mutex_unlock(&dir->d_inode->i_mutex);
  53         dput(dir);
  54 }
  55
  56 void ecryptfs_copy_inode_size(struct inode *dst, const struct inode *src)
  57 {
  58         i_size_write(dst, i_size_read((struct inode *)src));
  59         dst->i_blocks = src->i_blocks;
  60 }
  61
  62 void ecryptfs_copy_attr_atime(struct inode *dest, const struct inode *src)
  63 {
  64         dest->i_atime = src->i_atime;
  65 }
  66
  67 static void ecryptfs_copy_attr_times(struct inode *dest,
  68                                      const struct inode *src)
  69 {
  70         dest->i_atime = src->i_atime;
  71         dest->i_mtime = src->i_mtime;
  72         dest->i_ctime = src->i_ctime;
  73 }
  74
  75 static void ecryptfs_copy_attr_timesizes(struct inode *dest,
  76                                          const struct inode *src)
  77 {
  78         dest->i_atime = src->i_atime;
  79         dest->i_mtime = src->i_mtime;
  80         dest->i_ctime = src->i_ctime;
  81         ecryptfs_copy_inode_size(dest, src);
  82 }
  83
  84 void ecryptfs_copy_attr_all(struct inode *dest, const struct inode *src)
  85 {
  86         dest->i_mode = src->i_mode;
  87         dest->i_nlink = src->i_nlink;
  88         dest->i_uid = src->i_uid;
  89         dest->i_gid = src->i_gid;
  90         dest->i_rdev = src->i_rdev;
  91         dest->i_atime = src->i_atime;
  92         dest->i_mtime = src->i_mtime;
  93         dest->i_ctime = src->i_ctime;
  94         dest->i_blkbits = src->i_blkbits;
  95         dest->i_flags = src->i_flags;
  96 }
  97
  98 /**
  99  * ecryptfs_create_underlying_file
 100  * @lower_dir_inode: inode of the parent in the lower fs of the new file
 101  * @lower_dentry: New file's dentry in the lower fs
 102  * @ecryptfs_dentry: New file's dentry in ecryptfs
 103  * @mode: The mode of the new file
 104  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 105  *
 106  * Creates the file in the lower file system.
 107  *
 108  * Returns zero on success; non-zero on error condition
 109  */
 110 static int
 111 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
 112                                 struct dentry *dentry, int mode,
 113                                 struct nameidata *nd)
 114 {
 115         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 116         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 117         struct dentry *dentry_save;
 118         struct vfsmount *vfsmount_save;
 119         int rc;
 120
 121         dentry_save = nd->dentry;
 122         vfsmount_save = nd->mnt;
 123         nd->dentry = lower_dentry;
 124         nd->mnt = lower_mnt;
 125         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
 126         nd->dentry = dentry_save;
 127         nd->mnt = vfsmount_save;
 128         return rc;
 129 }
 130
 131 /**
 132  * ecryptfs_do_create
 133  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 134  * @ecryptfs_dentry: New file's dentry in ecryptfs
 135  * @mode: The mode of the new file
 136  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 137  *
 138  * Creates the underlying file and the eCryptfs inode which will link to
 139  * it. It will also update the eCryptfs directory inode to mimic the
 140  * stat of the lower directory inode.
 141  *
 142  * Returns zero on success; non-zero on error condition
 143  */
 144 static int
 145 ecryptfs_do_create(struct inode *directory_inode,
 146                    struct dentry *ecryptfs_dentry, int mode,
 147                    struct nameidata *nd)
 148 {
 149         int rc;
 150         struct dentry *lower_dentry;
 151         struct dentry *lower_dir_dentry;
 152
 153         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 154         lower_dir_dentry = lock_parent(lower_dentry);
 155         if (unlikely(IS_ERR(lower_dir_dentry))) {
 156                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 157                                 "dentry\n");
 158                 rc = PTR_ERR(lower_dir_dentry);
 159                 goto out;
 160         }
 161         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 162                                              ecryptfs_dentry, mode, nd);
 163         if (unlikely(rc)) {
 164                 ecryptfs_printk(KERN_ERR,
 165                                 "Failure to create underlying file\n");
 166                 goto out_lock;
 167         }
 168         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 169                                 directory_inode->i_sb, 0);
 170         if (rc) {
 171                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 172                 goto out_lock;
 173         }
 174         ecryptfs_copy_attr_timesizes(directory_inode,
 175                                      lower_dir_dentry->d_inode);
 176 out_lock:
 177         unlock_dir(lower_dir_dentry);
 178 out:
 179         return rc;
 180 }
 181
 182 /**
 183  * grow_file
 184  * @ecryptfs_dentry: the ecryptfs dentry
 185  * @lower_file: The lower file
 186  * @inode: The ecryptfs inode
 187  * @lower_inode: The lower inode
 188  *
 189  * This is the code which will grow the file to its correct size.
 190  */
 191 static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
 192                      struct inode *inode, struct inode *lower_inode)
 193 {
 194         int rc = 0;
 195         struct file fake_file;
 196         struct ecryptfs_file_info tmp_file_info;
 197
 198         memset(&fake_file, 0, sizeof(fake_file));
 199         fake_file.f_dentry = ecryptfs_dentry;
 200         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 201         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 202         ecryptfs_set_file_lower(&fake_file, lower_file);
 203         rc = ecryptfs_fill_zeros(&fake_file, 1);
 204         if (rc) {
 205                 ECRYPTFS_SET_FLAG(
 206                         ecryptfs_inode_to_private(inode)->crypt_stat.flags,
 207                         ECRYPTFS_SECURITY_WARNING);
 208                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
 209                                 "in file; rc = [%d]\n", rc);
 210                 goto out;
 211         }
 212         i_size_write(inode, 0);
 213         ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
 214         ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
 215                           ECRYPTFS_NEW_FILE);
 216 out:
 217         return rc;
 218 }
 219
 220 /**
 221  * ecryptfs_initialize_file
 222  *
 223  * Cause the file to be changed from a basic empty file to an ecryptfs
 224  * file with a header and first data page.
 225  *
 226  * Returns zero on success
 227  */
 228 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 229 {
 230         int rc = 0;
 231         int lower_flags;
 232         struct ecryptfs_crypt_stat *crypt_stat;
 233         struct dentry *lower_dentry;
 234         struct dentry *tlower_dentry = NULL;
 235         struct file *lower_file;
 236         struct inode *inode, *lower_inode;
 237         struct vfsmount *lower_mnt;
 238
 239         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 240         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
 241                         lower_dentry->d_name.name);
 242         inode = ecryptfs_dentry->d_inode;
 243         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 244         tlower_dentry = dget(lower_dentry);
 245         if (!tlower_dentry) {
 246                 rc = -ENOMEM;
 247                 ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry\n");
 248                 goto out;
 249         }
 250         lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
 251 #if BITS_PER_LONG != 32
 252         lower_flags |= O_LARGEFILE;
 253 #endif
 254         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 255         mntget(lower_mnt);
 256         /* Corresponding fput() at end of this function */
 257         lower_file = dentry_open(tlower_dentry, lower_mnt, lower_flags);
 258         if (IS_ERR(lower_file)) {
 259                 rc = PTR_ERR(lower_file);
 260                 ecryptfs_printk(KERN_ERR,
 261                                 "Error opening dentry; rc = [%i]\n", rc);
 262                 goto out;
 263         }
 264         /* fput(lower_file) should handle the puts if we do this */
 265         lower_file->f_dentry = tlower_dentry;
 266         lower_file->f_vfsmnt = lower_mnt;
 267         lower_inode = tlower_dentry->d_inode;
 268         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 269                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 270                 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
 271                 goto out_fput;
 272         }
 273         ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
 274         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 275         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 276         if (rc) {
 277                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
 278                                 "context\n");
 279                 goto out_fput;
 280         }
 281         rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
 282         if (rc) {
 283                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
 284                 goto out_fput;
 285         }
 286         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
 287 out_fput:
 288         fput(lower_file);
 289 out:
 290         return rc;
 291 }
 292
 293 /**
 294  * ecryptfs_create
 295  * @dir: The inode of the directory in which to create the file.
 296  * @dentry: The eCryptfs dentry
 297  * @mode: The mode of the new file.
 298  * @nd: nameidata
 299  *
 300  * Creates a new file.
 301  *
 302  * Returns zero on success; non-zero on error condition
 303  */
 304 static int
 305 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 306                 int mode, struct nameidata *nd)
 307 {
 308         int rc;
 309
 310         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 311         if (unlikely(rc)) {
 312                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 313                                 "lower filesystem\n");
 314                 goto out;
 315         }
 316         /* At this point, a file exists on "disk"; we need to make sure
 317          * that this on disk file is prepared to be an ecryptfs file */
 318         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 319 out:
 320         return rc;
 321 }
 322
 323 /**
 324  * ecryptfs_lookup
 325  * @dir: inode
 326  * @dentry: The dentry
 327  * @nd: nameidata, may be NULL
 328  *
 329  * Find a file on disk. If the file does not exist, then we'll add it to the
 330  * dentry cache and continue on to read it from the disk.
 331  */
 332 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 333                                       struct nameidata *nd)
 334 {
 335         int rc = 0;
 336         struct dentry *lower_dir_dentry;
 337         struct dentry *lower_dentry;
 338         struct vfsmount *lower_mnt;
 339         struct dentry *tlower_dentry = NULL;
 340         char *encoded_name;
 341         unsigned int encoded_namelen;
 342         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 343         char *page_virt = NULL;
 344         struct inode *lower_inode;
 345         u64 file_size;
 346
 347         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 348         dentry->d_op = &ecryptfs_dops;
 349         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 350             || (dentry->d_name.len == 2 && !strcmp(dentry->d_name.name, "..")))
 351                 goto out_drop;
 352         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 353                                                    dentry->d_name.name,
 354                                                    dentry->d_name.len,
 355                                                    &encoded_name);
 356         if (encoded_namelen < 0) {
 357                 rc = encoded_namelen;
 358                 goto out_drop;
 359         }
 360         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 361                         "= [%d]\n", encoded_name, encoded_namelen);
 362         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 363                                       encoded_namelen - 1);
 364         kfree(encoded_name);
 365         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 366         if (IS_ERR(lower_dentry)) {
 367                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 368                 rc = PTR_ERR(lower_dentry);
 369                 goto out_drop;
 370         }
 371         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 372                 "d_name.name = [%s]\n", lower_dentry,
 373                 lower_dentry->d_name.name);
 374         lower_inode = lower_dentry->d_inode;
 375         ecryptfs_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 376         BUG_ON(!atomic_read(&lower_dentry->d_count));
 377         ecryptfs_set_dentry_private(dentry,
 378                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 379                                                      SLAB_KERNEL));
 380         if (!ecryptfs_dentry_to_private(dentry)) {
 381                 rc = -ENOMEM;
 382                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 383                                 "to allocate ecryptfs_dentry_info struct\n");
 384                 goto out_dput;
 385         }
 386         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 387         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 388         if (!lower_dentry->d_inode) {
 389                 /* We want to add because we couldn't find in lower */
 390                 d_add(dentry, NULL);
 391                 goto out;
 392         }
 393         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 394         if (rc) {
 395                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 396                 goto out_dput;
 397         }
 398         if (S_ISDIR(lower_inode->i_mode)) {
 399                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 400                 goto out;
 401         }
 402         if (S_ISLNK(lower_inode->i_mode)) {
 403                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 404                 goto out;
 405         }
 406         if (!nd) {
 407                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 408                                 "as we *think* we are about to unlink\n");
 409                 goto out;
 410         }
 411         tlower_dentry = dget(lower_dentry);
 412         if (!tlower_dentry || IS_ERR(tlower_dentry)) {
 413                 rc = -ENOMEM;
 414                 ecryptfs_printk(KERN_ERR, "Cannot dget lower_dentry\n");
 415                 goto out_dput;
 416         }
 417         /* Released in this function */
 418         page_virt =
 419             (char *)kmem_cache_alloc(ecryptfs_header_cache_2,
 420                                      SLAB_USER);
 421         if (!page_virt) {
 422                 rc = -ENOMEM;
 423                 ecryptfs_printk(KERN_ERR,
 424                                 "Cannot ecryptfs_kmalloc a page\n");
 425                 goto out_dput;
 426         }
 427         memset(page_virt, 0, PAGE_CACHE_SIZE);
 428         rc = ecryptfs_read_header_region(page_virt, tlower_dentry, nd->mnt);
 429         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 430         if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
 431                 ecryptfs_set_default_sizes(crypt_stat);
 432         if (rc) {
 433                 rc = 0;
 434                 ecryptfs_printk(KERN_WARNING, "Error reading header region;"
 435                                 " assuming unencrypted\n");
 436         } else {
 437                 if (!contains_ecryptfs_marker(page_virt
 438                                               + ECRYPTFS_FILE_SIZE_BYTES)) {
 439                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 440                         goto out;
 441                 }
 442                 memcpy(&file_size, page_virt, sizeof(file_size));
 443                 file_size = be64_to_cpu(file_size);
 444                 i_size_write(dentry->d_inode, (loff_t)file_size);
 445         }
 446         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 447         goto out;
 448
 449 out_dput:
 450         dput(lower_dentry);
 451         if (tlower_dentry)
 452                 dput(tlower_dentry);
 453 out_drop:
 454         d_drop(dentry);
 455 out:
 456         return ERR_PTR(rc);
 457 }
 458
 459 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 460                          struct dentry *new_dentry)
 461 {
 462         struct dentry *lower_old_dentry;
 463         struct dentry *lower_new_dentry;
 464         struct dentry *lower_dir_dentry;
 465         u64 file_size_save;
 466         int rc;
 467
 468         file_size_save = i_size_read(old_dentry->d_inode);
 469         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 470         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 471         dget(lower_old_dentry);
 472         dget(lower_new_dentry);
 473         lower_dir_dentry = lock_parent(lower_new_dentry);
 474         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 475                       lower_new_dentry);
 476         if (rc || !lower_new_dentry->d_inode)
 477                 goto out_lock;
 478         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 479         if (rc)
 480                 goto out_lock;
 481         ecryptfs_copy_attr_timesizes(dir, lower_new_dentry->d_inode);
 482         old_dentry->d_inode->i_nlink =
 483                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 484         i_size_write(new_dentry->d_inode, file_size_save);
 485 out_lock:
 486         unlock_dir(lower_dir_dentry);
 487         dput(lower_new_dentry);
 488         dput(lower_old_dentry);
 489         if (!new_dentry->d_inode)
 490                 d_drop(new_dentry);
 491         return rc;
 492 }
 493
 494 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 495 {
 496         int rc = 0;
 497         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 498         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 499
 500         lock_parent(lower_dentry);
 501         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 502         if (rc) {
 503                 ecryptfs_printk(KERN_ERR, "Error in vfs_unlink\n");
 504                 goto out_unlock;
 505         }
 506         ecryptfs_copy_attr_times(dir, lower_dir_inode);
 507         dentry->d_inode->i_nlink =
 508                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 509         dentry->d_inode->i_ctime = dir->i_ctime;
 510 out_unlock:
 511         unlock_parent(lower_dentry);
 512         return rc;
 513 }
 514
 515 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 516                             const char *symname)
 517 {
 518         int rc;
 519         struct dentry *lower_dentry;
 520         struct dentry *lower_dir_dentry;
 521         umode_t mode;
 522         char *encoded_symname;
 523         unsigned int encoded_symlen;
 524         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 525
 526         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 527         dget(lower_dentry);
 528         lower_dir_dentry = lock_parent(lower_dentry);
 529         mode = S_IALLUGO;
 530         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 531                                                   strlen(symname),
 532                                                   &encoded_symname);
 533         if (encoded_symlen < 0) {
 534                 rc = encoded_symlen;
 535                 goto out_lock;
 536         }
 537         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 538                          encoded_symname, mode);
 539         kfree(encoded_symname);
 540         if (rc || !lower_dentry->d_inode)
 541                 goto out_lock;
 542         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 543         if (rc)
 544                 goto out_lock;
 545         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
 546 out_lock:
 547         unlock_dir(lower_dir_dentry);
 548         dput(lower_dentry);
 549         if (!dentry->d_inode)
 550                 d_drop(dentry);
 551         return rc;
 552 }
 553
 554 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 555 {
 556         int rc;
 557         struct dentry *lower_dentry;
 558         struct dentry *lower_dir_dentry;
 559
 560         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 561         lower_dir_dentry = lock_parent(lower_dentry);
 562         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 563         if (rc || !lower_dentry->d_inode)
 564                 goto out;
 565         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 566         if (rc)
 567                 goto out;
 568         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
 569         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 570 out:
 571         unlock_dir(lower_dir_dentry);
 572         if (!dentry->d_inode)
 573                 d_drop(dentry);
 574         return rc;
 575 }
 576
 577 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 578 {
 579         int rc = 0;
 580         struct dentry *tdentry = NULL;
 581         struct dentry *lower_dentry;
 582         struct dentry *tlower_dentry = NULL;
 583         struct dentry *lower_dir_dentry;
 584
 585         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 586         if (!(tdentry = dget(dentry))) {
 587                 rc = -EINVAL;
 588                 ecryptfs_printk(KERN_ERR, "Error dget'ing dentry [%p]\n",
 589                                 dentry);
 590                 goto out;
 591         }
 592         lower_dir_dentry = lock_parent(lower_dentry);
 593         if (!(tlower_dentry = dget(lower_dentry))) {
 594                 rc = -EINVAL;
 595                 ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry "
 596                                 "[%p]\n", lower_dentry);
 597                 goto out;
 598         }
 599         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 600         if (!rc) {
 601                 d_delete(tlower_dentry);
 602                 tlower_dentry = NULL;
 603         }
 604         ecryptfs_copy_attr_times(dir, lower_dir_dentry->d_inode);
 605         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 606         unlock_dir(lower_dir_dentry);
 607         if (!rc)
 608                 d_drop(dentry);
 609 out:
 610         if (tdentry)
 611                 dput(tdentry);
 612         if (tlower_dentry)
 613                 dput(tlower_dentry);
 614         return rc;
 615 }
 616
 617 static int
 618 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 619 {
 620         int rc;
 621         struct dentry *lower_dentry;
 622         struct dentry *lower_dir_dentry;
 623
 624         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 625         lower_dir_dentry = lock_parent(lower_dentry);
 626         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 627         if (rc || !lower_dentry->d_inode)
 628                 goto out;
 629         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 630         if (rc)
 631                 goto out;
 632         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
 633 out:
 634         unlock_dir(lower_dir_dentry);
 635         if (!dentry->d_inode)
 636                 d_drop(dentry);
 637         return rc;
 638 }
 639
 640 static int
 641 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 642                 struct inode *new_dir, struct dentry *new_dentry)
 643 {
 644         int rc;
 645         struct dentry *lower_old_dentry;
 646         struct dentry *lower_new_dentry;
 647         struct dentry *lower_old_dir_dentry;
 648         struct dentry *lower_new_dir_dentry;
 649
 650         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 651         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 652         dget(lower_old_dentry);
 653         dget(lower_new_dentry);
 654         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 655         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 656         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 657         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 658                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 659         if (rc)
 660                 goto out_lock;
 661         ecryptfs_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
 662         if (new_dir != old_dir)
 663                 ecryptfs_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
 664 out_lock:
 665         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 666         dput(lower_new_dentry);
 667         dput(lower_old_dentry);
 668         return rc;
 669 }
 670
 671 static int
 672 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 673 {
 674         int rc;
 675         struct dentry *lower_dentry;
 676         char *decoded_name;
 677         char *lower_buf;
 678         mm_segment_t old_fs;
 679         struct ecryptfs_crypt_stat *crypt_stat;
 680
 681         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 682         if (!lower_dentry->d_inode->i_op ||
 683             !lower_dentry->d_inode->i_op->readlink) {
 684                 rc = -EINVAL;
 685                 goto out;
 686         }
 687         /* Released in this function */
 688         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 689         if (lower_buf == NULL) {
 690                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 691                 rc = -ENOMEM;
 692                 goto out;
 693         }
 694         old_fs = get_fs();
 695         set_fs(get_ds());
 696         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 697                         "lower_dentry->d_name.name = [%s]\n",
 698                         lower_dentry->d_name.name);
 699         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 700                                                    (char __user *)lower_buf,
 701                                                    bufsiz);
 702         set_fs(old_fs);
 703         if (rc >= 0) {
 704                 crypt_stat = NULL;
 705                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 706                                               &decoded_name);
 707                 if (rc == -ENOMEM)
 708                         goto out_free_lower_buf;
 709                 if (rc > 0) {
 710                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 711                                         "to userspace: [%*s]\n", rc,
 712                                         decoded_name);
 713                         if (copy_to_user(buf, decoded_name, rc))
 714                                 rc = -EFAULT;
 715                 }
 716                 kfree(decoded_name);
 717                 ecryptfs_copy_attr_atime(dentry->d_inode,
 718                                          lower_dentry->d_inode);
 719         }
 720 out_free_lower_buf:
 721         kfree(lower_buf);
 722 out:
 723         return rc;
 724 }
 725
 726 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 727 {
 728         char *buf;
 729         int len = PAGE_SIZE, rc;
 730         mm_segment_t old_fs;
 731
 732         /* Released in ecryptfs_put_link(); only release here on error */
 733         buf = kmalloc(len, GFP_KERNEL);
 734         if (!buf) {
 735                 rc = -ENOMEM;
 736                 goto out;
 737         }
 738         old_fs = get_fs();
 739         set_fs(get_ds());
 740         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 741                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 742         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 743         buf[rc] = '\0';
 744         set_fs(old_fs);
 745         if (rc < 0)
 746                 goto out_free;
 747         rc = 0;
 748         nd_set_link(nd, buf);
 749         goto out;
 750 out_free:
 751         kfree(buf);
 752 out:
 753         return ERR_PTR(rc);
 754 }
 755
 756 static void
 757 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 758 {
 759         /* Free the char* */
 760         kfree(nd_get_link(nd));
 761 }
 762
 763 /**
 764  * upper_size_to_lower_size
 765  * @crypt_stat: Crypt_stat associated with file
 766  * @upper_size: Size of the upper file
 767  *
 768  * Calculate the requried size of the lower file based on the
 769  * specified size of the upper file. This calculation is based on the
 770  * number of headers in the underlying file and the extent size.
 771  *
 772  * Returns Calculated size of the lower file.
 773  */
 774 static loff_t
 775 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 776                          loff_t upper_size)
 777 {
 778         loff_t lower_size;
 779
 780         lower_size = ( crypt_stat->header_extent_size
 781                        * crypt_stat->num_header_extents_at_front );
 782         if (upper_size != 0) {
 783                 loff_t num_extents;
 784
 785                 num_extents = upper_size >> crypt_stat->extent_shift;
 786                 if (upper_size & ~crypt_stat->extent_mask)
 787                         num_extents++;
 788                 lower_size += (num_extents * crypt_stat->extent_size);
 789         }
 790         return lower_size;
 791 }
 792
 793 /**
 794  * ecryptfs_truncate
 795  * @dentry: The ecryptfs layer dentry
 796  * @new_length: The length to expand the file to
 797  *
 798  * Function to handle truncations modifying the size of the file. Note
 799  * that the file sizes are interpolated. When expanding, we are simply
 800  * writing strings of 0's out. When truncating, we need to modify the
 801  * underlying file size according to the page index interpolations.
 802  *
 803  * Returns zero on success; non-zero otherwise
 804  */
 805 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 806 {
 807         int rc = 0;
 808         struct inode *inode = dentry->d_inode;
 809         struct dentry *lower_dentry;
 810         struct vfsmount *lower_mnt;
 811         struct file fake_ecryptfs_file, *lower_file = NULL;
 812         struct ecryptfs_crypt_stat *crypt_stat;
 813         loff_t i_size = i_size_read(inode);
 814         loff_t lower_size_before_truncate;
 815         loff_t lower_size_after_truncate;
 816
 817         if (unlikely((new_length == i_size)))
 818                 goto out;
 819         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 820         /* Set up a fake ecryptfs file, this is used to interface with
 821          * the file in the underlying filesystem so that the
 822          * truncation has an effect there as well. */
 823         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 824         fake_ecryptfs_file.f_dentry = dentry;
 825         /* Released at out_free: label */
 826         ecryptfs_set_file_private(&fake_ecryptfs_file,
 827                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 828                                                    SLAB_KERNEL));
 829         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 830                 rc = -ENOMEM;
 831                 goto out;
 832         }
 833         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 834         /* This dget & mntget is released through fput at out_fput: */
 835         dget(lower_dentry);
 836         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 837         mntget(lower_mnt);
 838         lower_file = dentry_open(lower_dentry, lower_mnt, O_RDWR);
 839         if (unlikely(IS_ERR(lower_file))) {
 840                 rc = PTR_ERR(lower_file);
 841                 goto out_free;
 842         }
 843         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 844         /* Switch on growing or shrinking file */
 845         if (new_length > i_size) {
 846                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 847                 if (rc) {
 848                         ecryptfs_printk(KERN_ERR,
 849                                         "Problem with fill_zeros\n");
 850                         goto out_fput;
 851                 }
 852                 i_size_write(inode, new_length);
 853                 rc = ecryptfs_write_inode_size_to_header(lower_file,
 854                                                          lower_dentry->d_inode,
 855                                                          inode);
 856                 if (rc) {
 857                         ecryptfs_printk(KERN_ERR,
 858                                         "Problem with ecryptfs_write"
 859                                         "_inode_size\n");
 860                         goto out_fput;
 861                 }
 862         } else { /* new_length < i_size_read(inode) */
 863                 vmtruncate(inode, new_length);
 864                 ecryptfs_write_inode_size_to_header(lower_file,
 865                                                     lower_dentry->d_inode,
 866                                                     inode);
 867                 /* We are reducing the size of the ecryptfs file, and need to
 868                  * know if we need to reduce the size of the lower file. */
 869                 lower_size_before_truncate =
 870                     upper_size_to_lower_size(crypt_stat, i_size);
 871                 lower_size_after_truncate =
 872                     upper_size_to_lower_size(crypt_stat, new_length);
 873                 if (lower_size_after_truncate < lower_size_before_truncate)
 874                         vmtruncate(lower_dentry->d_inode,
 875                                    lower_size_after_truncate);
 876         }
 877         /* Update the access times */
 878         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 879                 = CURRENT_TIME;
 880         mark_inode_dirty_sync(inode);
 881 out_fput:
 882         fput(lower_file);
 883 out_free:
 884         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 885                 kmem_cache_free(ecryptfs_file_info_cache,
 886                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 887 out:
 888         return rc;
 889 }
 890
 891 static int
 892 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 893 {
 894         int rc;
 895
 896         if (nd) {
 897                 struct vfsmount *vfsmnt_save = nd->mnt;
 898                 struct dentry *dentry_save = nd->dentry;
 899
 900                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 901                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 902                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 903                 nd->mnt = vfsmnt_save;
 904                 nd->dentry = dentry_save;
 905         } else
 906                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 907         return rc;
 908 }
 909
 910 /**
 911  * ecryptfs_setattr
 912  * @dentry: dentry handle to the inode to modify
 913  * @ia: Structure with flags of what to change and values
 914  *
 915  * Updates the metadata of an inode. If the update is to the size
 916  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 917  * of both the ecryptfs inode and the lower inode.
 918  *
 919  * All other metadata changes will be passed right to the lower filesystem,
 920  * and we will just update our inode to look like the lower.
 921  */
 922 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 923 {
 924         int rc = 0;
 925         struct dentry *lower_dentry;
 926         struct inode *inode;
 927         struct inode *lower_inode;
 928         struct ecryptfs_crypt_stat *crypt_stat;
 929
 930         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 931         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 932         inode = dentry->d_inode;
 933         lower_inode = ecryptfs_inode_to_lower(inode);
 934         if (ia->ia_valid & ATTR_SIZE) {
 935                 ecryptfs_printk(KERN_DEBUG,
 936                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 937                                 ia->ia_valid, ATTR_SIZE);
 938                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 939                 /* ecryptfs_truncate handles resizing of the lower file */
 940                 ia->ia_valid &= ~ATTR_SIZE;
 941                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 942                                 ia->ia_valid);
 943                 if (rc < 0)
 944                         goto out;
 945         }
 946         rc = notify_change(lower_dentry, ia);
 947 out:
 948         ecryptfs_copy_attr_all(inode, lower_inode);
 949         return rc;
 950 }
 951
 952 static int
 953 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 954                   size_t size, int flags)
 955 {
 956         int rc = 0;
 957         struct dentry *lower_dentry;
 958
 959         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 960         if (!lower_dentry->d_inode->i_op->setxattr) {
 961                 rc = -ENOSYS;
 962                 goto out;
 963         }
 964         mutex_lock(&lower_dentry->d_inode->i_mutex);
 965         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 966                                                    size, flags);
 967         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 968 out:
 969         return rc;
 970 }
 971
 972 static ssize_t
 973 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 974                   size_t size)
 975 {
 976         int rc = 0;
 977         struct dentry *lower_dentry;
 978
 979         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 980         if (!lower_dentry->d_inode->i_op->getxattr) {
 981                 rc = -ENOSYS;
 982                 goto out;
 983         }
 984         mutex_lock(&lower_dentry->d_inode->i_mutex);
 985         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 986                                                    size);
 987         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 988 out:
 989         return rc;
 990 }
 991
 992 static ssize_t
 993 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 994 {
 995         int rc = 0;
 996         struct dentry *lower_dentry;
 997
 998         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 999         if (!lower_dentry->d_inode->i_op->listxattr) {
1000                 rc = -ENOSYS;
1001                 goto out;
1002         }
1003         mutex_lock(&lower_dentry->d_inode->i_mutex);
1004         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1005         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1006 out:
1007         return rc;
1008 }
1009
1010 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1011 {
1012         int rc = 0;
1013         struct dentry *lower_dentry;
1014
1015         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1016         if (!lower_dentry->d_inode->i_op->removexattr) {
1017                 rc = -ENOSYS;
1018                 goto out;
1019         }
1020         mutex_lock(&lower_dentry->d_inode->i_mutex);
1021         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1022         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1023 out:
1024         return rc;
1025 }
1026
1027 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1028 {
1029         if ((ecryptfs_inode_to_lower(inode)
1030              == (struct inode *)candidate_lower_inode))
1031                 return 1;
1032         else
1033                 return 0;
1034 }
1035
1036 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1037 {
1038         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1039         return 0;
1040 }
1041
1042 struct inode_operations ecryptfs_symlink_iops = {
1043         .readlink = ecryptfs_readlink,
1044         .follow_link = ecryptfs_follow_link,
1045         .put_link = ecryptfs_put_link,
1046         .permission = ecryptfs_permission,
1047         .setattr = ecryptfs_setattr,
1048         .setxattr = ecryptfs_setxattr,
1049         .getxattr = ecryptfs_getxattr,
1050         .listxattr = ecryptfs_listxattr,
1051         .removexattr = ecryptfs_removexattr
1052 };
1053
1054 struct inode_operations ecryptfs_dir_iops = {
1055         .create = ecryptfs_create,
1056         .lookup = ecryptfs_lookup,
1057         .link = ecryptfs_link,
1058         .unlink = ecryptfs_unlink,
1059         .symlink = ecryptfs_symlink,
1060         .mkdir = ecryptfs_mkdir,
1061         .rmdir = ecryptfs_rmdir,
1062         .mknod = ecryptfs_mknod,
1063         .rename = ecryptfs_rename,
1064         .permission = ecryptfs_permission,
1065         .setattr = ecryptfs_setattr,
1066         .setxattr = ecryptfs_setxattr,
1067         .getxattr = ecryptfs_getxattr,
1068         .listxattr = ecryptfs_listxattr,
1069         .removexattr = ecryptfs_removexattr
1070 };
1071
1072 struct inode_operations ecryptfs_main_iops = {
1073         .permission = ecryptfs_permission,
1074         .setattr = ecryptfs_setattr,
1075         .setxattr = ecryptfs_setxattr,
1076         .getxattr = ecryptfs_getxattr,
1077         .listxattr = ecryptfs_listxattr,
1078         .removexattr = ecryptfs_removexattr
1079 };