err.no Git - linux-2.6/blob - fs/ecryptfs/inode.c

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