fs/ecryptfs/inode.c

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