git.oblomov.eu 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 "ecryptfs_kernel.h"
  35
  36 static struct dentry *lock_parent(struct dentry *dentry)
  37 {
  38         struct dentry *dir;
  39
  40         dir = dget(dentry->d_parent);
  41         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
  42         return dir;
  43 }
  44
  45 static void unlock_parent(struct dentry *dentry)
  46 {
  47         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
  48         dput(dentry->d_parent);
  49 }
  50
  51 static void unlock_dir(struct dentry *dir)
  52 {
  53         mutex_unlock(&dir->d_inode->i_mutex);
  54         dput(dir);
  55 }
  56
  57 /**
  58  * ecryptfs_create_underlying_file
  59  * @lower_dir_inode: inode of the parent in the lower fs of the new file
  60  * @lower_dentry: New file's dentry in the lower fs
  61  * @ecryptfs_dentry: New file's dentry in ecryptfs
  62  * @mode: The mode of the new file
  63  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  64  *
  65  * Creates the file in the lower file system.
  66  *
  67  * Returns zero on success; non-zero on error condition
  68  */
  69 static int
  70 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
  71                                 struct dentry *dentry, int mode,
  72                                 struct nameidata *nd)
  73 {
  74         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  75         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  76         struct dentry *dentry_save;
  77         struct vfsmount *vfsmount_save;
  78         int rc;
  79
  80         dentry_save = nd->dentry;
  81         vfsmount_save = nd->mnt;
  82         nd->dentry = lower_dentry;
  83         nd->mnt = lower_mnt;
  84         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
  85         nd->dentry = dentry_save;
  86         nd->mnt = vfsmount_save;
  87         return rc;
  88 }
  89
  90 /**
  91  * ecryptfs_do_create
  92  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
  93  * @ecryptfs_dentry: New file's dentry in ecryptfs
  94  * @mode: The mode of the new file
  95  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  96  *
  97  * Creates the underlying file and the eCryptfs inode which will link to
  98  * it. It will also update the eCryptfs directory inode to mimic the
  99  * stat of the lower directory inode.
 100  *
 101  * Returns zero on success; non-zero on error condition
 102  */
 103 static int
 104 ecryptfs_do_create(struct inode *directory_inode,
 105                    struct dentry *ecryptfs_dentry, int mode,
 106                    struct nameidata *nd)
 107 {
 108         int rc;
 109         struct dentry *lower_dentry;
 110         struct dentry *lower_dir_dentry;
 111
 112         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 113         lower_dir_dentry = lock_parent(lower_dentry);
 114         if (unlikely(IS_ERR(lower_dir_dentry))) {
 115                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 116                                 "dentry\n");
 117                 rc = PTR_ERR(lower_dir_dentry);
 118                 goto out;
 119         }
 120         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 121                                              ecryptfs_dentry, mode, nd);
 122         if (unlikely(rc)) {
 123                 ecryptfs_printk(KERN_ERR,
 124                                 "Failure to create underlying file\n");
 125                 goto out_lock;
 126         }
 127         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 128                                 directory_inode->i_sb, 0);
 129         if (rc) {
 130                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 131                 goto out_lock;
 132         }
 133         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
 134         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
 135 out_lock:
 136         unlock_dir(lower_dir_dentry);
 137 out:
 138         return rc;
 139 }
 140
 141 /**
 142  * grow_file
 143  * @ecryptfs_dentry: the ecryptfs dentry
 144  * @lower_file: The lower file
 145  * @inode: The ecryptfs inode
 146  * @lower_inode: The lower inode
 147  *
 148  * This is the code which will grow the file to its correct size.
 149  */
 150 static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
 151                      struct inode *inode, struct inode *lower_inode)
 152 {
 153         int rc = 0;
 154         struct file fake_file;
 155         struct ecryptfs_file_info tmp_file_info;
 156
 157         memset(&fake_file, 0, sizeof(fake_file));
 158         fake_file.f_path.dentry = ecryptfs_dentry;
 159         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 160         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 161         ecryptfs_set_file_lower(&fake_file, lower_file);
 162         rc = ecryptfs_fill_zeros(&fake_file, 1);
 163         if (rc) {
 164                 ecryptfs_inode_to_private(inode)->crypt_stat.flags |=
 165                         ECRYPTFS_SECURITY_WARNING;
 166                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
 167                                 "in file; rc = [%d]\n", rc);
 168                 goto out;
 169         }
 170         i_size_write(inode, 0);
 171         rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode,
 172                         inode, ecryptfs_dentry,
 173                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 174         ecryptfs_inode_to_private(inode)->crypt_stat.flags |= ECRYPTFS_NEW_FILE;
 175 out:
 176         return rc;
 177 }
 178
 179 /**
 180  * ecryptfs_initialize_file
 181  *
 182  * Cause the file to be changed from a basic empty file to an ecryptfs
 183  * file with a header and first data page.
 184  *
 185  * Returns zero on success
 186  */
 187 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 188 {
 189         int rc = 0;
 190         int lower_flags;
 191         struct ecryptfs_crypt_stat *crypt_stat;
 192         struct dentry *lower_dentry;
 193         struct file *lower_file;
 194         struct inode *inode, *lower_inode;
 195         struct vfsmount *lower_mnt;
 196
 197         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 198         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
 199                         lower_dentry->d_name.name);
 200         inode = ecryptfs_dentry->d_inode;
 201         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 202         lower_flags = ((O_CREAT | O_TRUNC) & O_ACCMODE) | O_RDWR;
 203         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 204         /* Corresponding fput() at end of this function */
 205         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 206                                            lower_flags))) {
 207                 ecryptfs_printk(KERN_ERR,
 208                                 "Error opening dentry; rc = [%i]\n", rc);
 209                 goto out;
 210         }
 211         lower_inode = lower_dentry->d_inode;
 212         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 213                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 214                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 215                 goto out_fput;
 216         }
 217         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
 218         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 219         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 220         if (rc) {
 221                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
 222                                 "context\n");
 223                 goto out_fput;
 224         }
 225         rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
 226         if (rc) {
 227                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
 228                 goto out_fput;
 229         }
 230         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
 231 out_fput:
 232         if ((rc = ecryptfs_close_lower_file(lower_file)))
 233                 printk(KERN_ERR "Error closing lower_file\n");
 234 out:
 235         return rc;
 236 }
 237
 238 /**
 239  * ecryptfs_create
 240  * @dir: The inode of the directory in which to create the file.
 241  * @dentry: The eCryptfs dentry
 242  * @mode: The mode of the new file.
 243  * @nd: nameidata
 244  *
 245  * Creates a new file.
 246  *
 247  * Returns zero on success; non-zero on error condition
 248  */
 249 static int
 250 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 251                 int mode, struct nameidata *nd)
 252 {
 253         int rc;
 254
 255         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 256         if (unlikely(rc)) {
 257                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 258                                 "lower filesystem\n");
 259                 goto out;
 260         }
 261         /* At this point, a file exists on "disk"; we need to make sure
 262          * that this on disk file is prepared to be an ecryptfs file */
 263         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 264 out:
 265         return rc;
 266 }
 267
 268 /**
 269  * ecryptfs_lookup
 270  * @dir: inode
 271  * @dentry: The dentry
 272  * @nd: nameidata, may be NULL
 273  *
 274  * Find a file on disk. If the file does not exist, then we'll add it to the
 275  * dentry cache and continue on to read it from the disk.
 276  */
 277 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 278                                       struct nameidata *nd)
 279 {
 280         int rc = 0;
 281         struct dentry *lower_dir_dentry;
 282         struct dentry *lower_dentry;
 283         struct vfsmount *lower_mnt;
 284         char *encoded_name;
 285         int encoded_namelen;
 286         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 287         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 288         char *page_virt = NULL;
 289         struct inode *lower_inode;
 290         u64 file_size;
 291
 292         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 293         dentry->d_op = &ecryptfs_dops;
 294         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 295             || (dentry->d_name.len == 2
 296                 && !strcmp(dentry->d_name.name, ".."))) {
 297                 d_drop(dentry);
 298                 goto out;
 299         }
 300         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 301                                                    dentry->d_name.name,
 302                                                    dentry->d_name.len,
 303                                                    &encoded_name);
 304         if (encoded_namelen < 0) {
 305                 rc = encoded_namelen;
 306                 d_drop(dentry);
 307                 goto out;
 308         }
 309         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 310                         "= [%d]\n", encoded_name, encoded_namelen);
 311         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 312                                       encoded_namelen - 1);
 313         kfree(encoded_name);
 314         if (IS_ERR(lower_dentry)) {
 315                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 316                 rc = PTR_ERR(lower_dentry);
 317                 d_drop(dentry);
 318                 goto out;
 319         }
 320         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 321         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 322                 "d_name.name = [%s]\n", lower_dentry,
 323                 lower_dentry->d_name.name);
 324         lower_inode = lower_dentry->d_inode;
 325         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 326         BUG_ON(!atomic_read(&lower_dentry->d_count));
 327         ecryptfs_set_dentry_private(dentry,
 328                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 329                                                      GFP_KERNEL));
 330         if (!ecryptfs_dentry_to_private(dentry)) {
 331                 rc = -ENOMEM;
 332                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 333                                 "to allocate ecryptfs_dentry_info struct\n");
 334                 goto out_dput;
 335         }
 336         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 337         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 338         if (!lower_dentry->d_inode) {
 339                 /* We want to add because we couldn't find in lower */
 340                 d_add(dentry, NULL);
 341                 goto out;
 342         }
 343         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 344         if (rc) {
 345                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 346                 goto out_dput;
 347         }
 348         if (S_ISDIR(lower_inode->i_mode)) {
 349                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 350                 goto out;
 351         }
 352         if (S_ISLNK(lower_inode->i_mode)) {
 353                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 354                 goto out;
 355         }
 356         if (!nd) {
 357                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 358                                 "as we *think* we are about to unlink\n");
 359                 goto out;
 360         }
 361         /* Released in this function */
 362         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 363                                       GFP_USER);
 364         if (!page_virt) {
 365                 rc = -ENOMEM;
 366                 ecryptfs_printk(KERN_ERR,
 367                                 "Cannot ecryptfs_kmalloc a page\n");
 368                 goto out_dput;
 369         }
 370         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 371         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 372                 ecryptfs_set_default_sizes(crypt_stat);
 373         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
 374                                                       nd->mnt);
 375         if (rc) {
 376                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 377                 if (rc) {
 378                         printk(KERN_DEBUG "Valid metadata not found in header "
 379                                "region or xattr region; treating file as "
 380                                "unencrypted\n");
 381                         rc = 0;
 382                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 383                         goto out;
 384                 }
 385                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 386         }
 387         mount_crypt_stat = &ecryptfs_superblock_to_private(
 388                 dentry->d_sb)->mount_crypt_stat;
 389         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 390                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 391                         file_size = (crypt_stat->header_extent_size
 392                                      + i_size_read(lower_dentry->d_inode));
 393                 else
 394                         file_size = i_size_read(lower_dentry->d_inode);
 395         } else {
 396                 memcpy(&file_size, page_virt, sizeof(file_size));
 397                 file_size = be64_to_cpu(file_size);
 398         }
 399         i_size_write(dentry->d_inode, (loff_t)file_size);
 400         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 401         goto out;
 402
 403 out_dput:
 404         dput(lower_dentry);
 405         d_drop(dentry);
 406 out:
 407         return ERR_PTR(rc);
 408 }
 409
 410 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 411                          struct dentry *new_dentry)
 412 {
 413         struct dentry *lower_old_dentry;
 414         struct dentry *lower_new_dentry;
 415         struct dentry *lower_dir_dentry;
 416         u64 file_size_save;
 417         int rc;
 418
 419         file_size_save = i_size_read(old_dentry->d_inode);
 420         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 421         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 422         dget(lower_old_dentry);
 423         dget(lower_new_dentry);
 424         lower_dir_dentry = lock_parent(lower_new_dentry);
 425         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 426                       lower_new_dentry);
 427         if (rc || !lower_new_dentry->d_inode)
 428                 goto out_lock;
 429         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 430         if (rc)
 431                 goto out_lock;
 432         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 433         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 434         old_dentry->d_inode->i_nlink =
 435                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 436         i_size_write(new_dentry->d_inode, file_size_save);
 437 out_lock:
 438         unlock_dir(lower_dir_dentry);
 439         dput(lower_new_dentry);
 440         dput(lower_old_dentry);
 441         d_drop(lower_old_dentry);
 442         d_drop(new_dentry);
 443         d_drop(old_dentry);
 444         return rc;
 445 }
 446
 447 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 448 {
 449         int rc = 0;
 450         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 451         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 452
 453         lock_parent(lower_dentry);
 454         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 455         if (rc) {
 456                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 457                 goto out_unlock;
 458         }
 459         fsstack_copy_attr_times(dir, lower_dir_inode);
 460         dentry->d_inode->i_nlink =
 461                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 462         dentry->d_inode->i_ctime = dir->i_ctime;
 463 out_unlock:
 464         unlock_parent(lower_dentry);
 465         return rc;
 466 }
 467
 468 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 469                             const char *symname)
 470 {
 471         int rc;
 472         struct dentry *lower_dentry;
 473         struct dentry *lower_dir_dentry;
 474         umode_t mode;
 475         char *encoded_symname;
 476         int encoded_symlen;
 477         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 478
 479         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 480         dget(lower_dentry);
 481         lower_dir_dentry = lock_parent(lower_dentry);
 482         mode = S_IALLUGO;
 483         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 484                                                   strlen(symname),
 485                                                   &encoded_symname);
 486         if (encoded_symlen < 0) {
 487                 rc = encoded_symlen;
 488                 goto out_lock;
 489         }
 490         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 491                          encoded_symname, mode);
 492         kfree(encoded_symname);
 493         if (rc || !lower_dentry->d_inode)
 494                 goto out_lock;
 495         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 496         if (rc)
 497                 goto out_lock;
 498         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 499         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 500 out_lock:
 501         unlock_dir(lower_dir_dentry);
 502         dput(lower_dentry);
 503         if (!dentry->d_inode)
 504                 d_drop(dentry);
 505         return rc;
 506 }
 507
 508 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 509 {
 510         int rc;
 511         struct dentry *lower_dentry;
 512         struct dentry *lower_dir_dentry;
 513
 514         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 515         lower_dir_dentry = lock_parent(lower_dentry);
 516         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 517         if (rc || !lower_dentry->d_inode)
 518                 goto out;
 519         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 520         if (rc)
 521                 goto out;
 522         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 523         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 524         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 525 out:
 526         unlock_dir(lower_dir_dentry);
 527         if (!dentry->d_inode)
 528                 d_drop(dentry);
 529         return rc;
 530 }
 531
 532 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 533 {
 534         struct dentry *lower_dentry;
 535         struct dentry *lower_dir_dentry;
 536         int rc;
 537
 538         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 539         dget(dentry);
 540         lower_dir_dentry = lock_parent(lower_dentry);
 541         dget(lower_dentry);
 542         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 543         dput(lower_dentry);
 544         if (!rc)
 545                 d_delete(lower_dentry);
 546         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 547         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 548         unlock_dir(lower_dir_dentry);
 549         if (!rc)
 550                 d_drop(dentry);
 551         dput(dentry);
 552         return rc;
 553 }
 554
 555 static int
 556 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 557 {
 558         int rc;
 559         struct dentry *lower_dentry;
 560         struct dentry *lower_dir_dentry;
 561
 562         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 563         lower_dir_dentry = lock_parent(lower_dentry);
 564         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 565         if (rc || !lower_dentry->d_inode)
 566                 goto out;
 567         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 568         if (rc)
 569                 goto out;
 570         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 571         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 572 out:
 573         unlock_dir(lower_dir_dentry);
 574         if (!dentry->d_inode)
 575                 d_drop(dentry);
 576         return rc;
 577 }
 578
 579 static int
 580 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 581                 struct inode *new_dir, struct dentry *new_dentry)
 582 {
 583         int rc;
 584         struct dentry *lower_old_dentry;
 585         struct dentry *lower_new_dentry;
 586         struct dentry *lower_old_dir_dentry;
 587         struct dentry *lower_new_dir_dentry;
 588
 589         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 590         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 591         dget(lower_old_dentry);
 592         dget(lower_new_dentry);
 593         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 594         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 595         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 596         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 597                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 598         if (rc)
 599                 goto out_lock;
 600         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 601         if (new_dir != old_dir)
 602                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 603 out_lock:
 604         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 605         dput(lower_new_dentry->d_parent);
 606         dput(lower_old_dentry->d_parent);
 607         dput(lower_new_dentry);
 608         dput(lower_old_dentry);
 609         return rc;
 610 }
 611
 612 static int
 613 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 614 {
 615         int rc;
 616         struct dentry *lower_dentry;
 617         char *decoded_name;
 618         char *lower_buf;
 619         mm_segment_t old_fs;
 620         struct ecryptfs_crypt_stat *crypt_stat;
 621
 622         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 623         if (!lower_dentry->d_inode->i_op ||
 624             !lower_dentry->d_inode->i_op->readlink) {
 625                 rc = -EINVAL;
 626                 goto out;
 627         }
 628         /* Released in this function */
 629         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 630         if (lower_buf == NULL) {
 631                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 632                 rc = -ENOMEM;
 633                 goto out;
 634         }
 635         old_fs = get_fs();
 636         set_fs(get_ds());
 637         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 638                         "lower_dentry->d_name.name = [%s]\n",
 639                         lower_dentry->d_name.name);
 640         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 641                                                    (char __user *)lower_buf,
 642                                                    bufsiz);
 643         set_fs(old_fs);
 644         if (rc >= 0) {
 645                 crypt_stat = NULL;
 646                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 647                                               &decoded_name);
 648                 if (rc == -ENOMEM)
 649                         goto out_free_lower_buf;
 650                 if (rc > 0) {
 651                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 652                                         "to userspace: [%*s]\n", rc,
 653                                         decoded_name);
 654                         if (copy_to_user(buf, decoded_name, rc))
 655                                 rc = -EFAULT;
 656                 }
 657                 kfree(decoded_name);
 658                 fsstack_copy_attr_atime(dentry->d_inode,
 659                                         lower_dentry->d_inode);
 660         }
 661 out_free_lower_buf:
 662         kfree(lower_buf);
 663 out:
 664         return rc;
 665 }
 666
 667 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 668 {
 669         char *buf;
 670         int len = PAGE_SIZE, rc;
 671         mm_segment_t old_fs;
 672
 673         /* Released in ecryptfs_put_link(); only release here on error */
 674         buf = kmalloc(len, GFP_KERNEL);
 675         if (!buf) {
 676                 rc = -ENOMEM;
 677                 goto out;
 678         }
 679         old_fs = get_fs();
 680         set_fs(get_ds());
 681         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 682                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 683         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 684         buf[rc] = '\0';
 685         set_fs(old_fs);
 686         if (rc < 0)
 687                 goto out_free;
 688         rc = 0;
 689         nd_set_link(nd, buf);
 690         goto out;
 691 out_free:
 692         kfree(buf);
 693 out:
 694         return ERR_PTR(rc);
 695 }
 696
 697 static void
 698 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 699 {
 700         /* Free the char* */
 701         kfree(nd_get_link(nd));
 702 }
 703
 704 /**
 705  * upper_size_to_lower_size
 706  * @crypt_stat: Crypt_stat associated with file
 707  * @upper_size: Size of the upper file
 708  *
 709  * Calculate the requried size of the lower file based on the
 710  * specified size of the upper file. This calculation is based on the
 711  * number of headers in the underlying file and the extent size.
 712  *
 713  * Returns Calculated size of the lower file.
 714  */
 715 static loff_t
 716 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 717                          loff_t upper_size)
 718 {
 719         loff_t lower_size;
 720
 721         lower_size = ( crypt_stat->header_extent_size
 722                        * crypt_stat->num_header_extents_at_front );
 723         if (upper_size != 0) {
 724                 loff_t num_extents;
 725
 726                 num_extents = upper_size >> crypt_stat->extent_shift;
 727                 if (upper_size & ~crypt_stat->extent_mask)
 728                         num_extents++;
 729                 lower_size += (num_extents * crypt_stat->extent_size);
 730         }
 731         return lower_size;
 732 }
 733
 734 /**
 735  * ecryptfs_truncate
 736  * @dentry: The ecryptfs layer dentry
 737  * @new_length: The length to expand the file to
 738  *
 739  * Function to handle truncations modifying the size of the file. Note
 740  * that the file sizes are interpolated. When expanding, we are simply
 741  * writing strings of 0's out. When truncating, we need to modify the
 742  * underlying file size according to the page index interpolations.
 743  *
 744  * Returns zero on success; non-zero otherwise
 745  */
 746 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 747 {
 748         int rc = 0;
 749         struct inode *inode = dentry->d_inode;
 750         struct dentry *lower_dentry;
 751         struct vfsmount *lower_mnt;
 752         struct file fake_ecryptfs_file, *lower_file = NULL;
 753         struct ecryptfs_crypt_stat *crypt_stat;
 754         loff_t i_size = i_size_read(inode);
 755         loff_t lower_size_before_truncate;
 756         loff_t lower_size_after_truncate;
 757
 758         if (unlikely((new_length == i_size)))
 759                 goto out;
 760         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 761         /* Set up a fake ecryptfs file, this is used to interface with
 762          * the file in the underlying filesystem so that the
 763          * truncation has an effect there as well. */
 764         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 765         fake_ecryptfs_file.f_path.dentry = dentry;
 766         /* Released at out_free: label */
 767         ecryptfs_set_file_private(&fake_ecryptfs_file,
 768                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 769                                                    GFP_KERNEL));
 770         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 771                 rc = -ENOMEM;
 772                 goto out;
 773         }
 774         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 775         /* This dget & mntget is released through fput at out_fput: */
 776         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 777         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 778                                            O_RDWR))) {
 779                 ecryptfs_printk(KERN_ERR,
 780                                 "Error opening dentry; rc = [%i]\n", rc);
 781                 goto out_free;
 782         }
 783         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 784         /* Switch on growing or shrinking file */
 785         if (new_length > i_size) {
 786                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 787                 if (rc) {
 788                         ecryptfs_printk(KERN_ERR,
 789                                         "Problem with fill_zeros\n");
 790                         goto out_fput;
 791                 }
 792                 i_size_write(inode, new_length);
 793                 rc = ecryptfs_write_inode_size_to_metadata(
 794                         lower_file, lower_dentry->d_inode, inode, dentry,
 795                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 796                 if (rc) {
 797                         printk(KERN_ERR "Problem with "
 798                                "ecryptfs_write_inode_size_to_metadata; "
 799                                "rc = [%d]\n", rc);
 800                         goto out_fput;
 801                 }
 802         } else { /* new_length < i_size_read(inode) */
 803                 pgoff_t index = 0;
 804                 int end_pos_in_page = -1;
 805
 806                 if (new_length != 0) {
 807                         index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
 808                         end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
 809                 }
 810                 if (end_pos_in_page != (PAGE_CACHE_SIZE - 1)) {
 811                         if ((rc = ecryptfs_write_zeros(&fake_ecryptfs_file,
 812                                                        index,
 813                                                        (end_pos_in_page + 1),
 814                                                        ((PAGE_CACHE_SIZE - 1)
 815                                                         - end_pos_in_page)))) {
 816                                 printk(KERN_ERR "Error attempting to zero out "
 817                                        "the remainder of the end page on "
 818                                        "reducing truncate; rc = [%d]\n", rc);
 819                                 goto out_fput;
 820                         }
 821                 }
 822                 vmtruncate(inode, new_length);
 823                 rc = ecryptfs_write_inode_size_to_metadata(
 824                         lower_file, lower_dentry->d_inode, inode, dentry,
 825                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 826                 if (rc) {
 827                         printk(KERN_ERR "Problem with "
 828                                "ecryptfs_write_inode_size_to_metadata; "
 829                                "rc = [%d]\n", rc);
 830                         goto out_fput;
 831                 }
 832                 /* We are reducing the size of the ecryptfs file, and need to
 833                  * know if we need to reduce the size of the lower file. */
 834                 lower_size_before_truncate =
 835                     upper_size_to_lower_size(crypt_stat, i_size);
 836                 lower_size_after_truncate =
 837                     upper_size_to_lower_size(crypt_stat, new_length);
 838                 if (lower_size_after_truncate < lower_size_before_truncate)
 839                         vmtruncate(lower_dentry->d_inode,
 840                                    lower_size_after_truncate);
 841         }
 842         /* Update the access times */
 843         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 844                 = CURRENT_TIME;
 845         mark_inode_dirty_sync(inode);
 846 out_fput:
 847         if ((rc = ecryptfs_close_lower_file(lower_file)))
 848                 printk(KERN_ERR "Error closing lower_file\n");
 849 out_free:
 850         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 851                 kmem_cache_free(ecryptfs_file_info_cache,
 852                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 853 out:
 854         return rc;
 855 }
 856
 857 static int
 858 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 859 {
 860         int rc;
 861
 862         if (nd) {
 863                 struct vfsmount *vfsmnt_save = nd->mnt;
 864                 struct dentry *dentry_save = nd->dentry;
 865
 866                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 867                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 868                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 869                 nd->mnt = vfsmnt_save;
 870                 nd->dentry = dentry_save;
 871         } else
 872                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 873         return rc;
 874 }
 875
 876 /**
 877  * ecryptfs_setattr
 878  * @dentry: dentry handle to the inode to modify
 879  * @ia: Structure with flags of what to change and values
 880  *
 881  * Updates the metadata of an inode. If the update is to the size
 882  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 883  * of both the ecryptfs inode and the lower inode.
 884  *
 885  * All other metadata changes will be passed right to the lower filesystem,
 886  * and we will just update our inode to look like the lower.
 887  */
 888 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 889 {
 890         int rc = 0;
 891         struct dentry *lower_dentry;
 892         struct inode *inode;
 893         struct inode *lower_inode;
 894         struct ecryptfs_crypt_stat *crypt_stat;
 895
 896         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 897         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 898                 ecryptfs_init_crypt_stat(crypt_stat);
 899         inode = dentry->d_inode;
 900         lower_inode = ecryptfs_inode_to_lower(inode);
 901         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 902         mutex_lock(&crypt_stat->cs_mutex);
 903         if (S_ISDIR(dentry->d_inode->i_mode))
 904                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 905         else if (S_ISREG(dentry->d_inode->i_mode)
 906                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 907                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 908                 struct vfsmount *lower_mnt;
 909                 struct file *lower_file = NULL;
 910                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 911                 int lower_flags;
 912
 913                 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 914                 lower_flags = O_RDONLY;
 915                 if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
 916                                                    lower_mnt, lower_flags))) {
 917                         printk(KERN_ERR
 918                                "Error opening lower file; rc = [%d]\n", rc);
 919                         mutex_unlock(&crypt_stat->cs_mutex);
 920                         goto out;
 921                 }
 922                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 923                         dentry->d_sb)->mount_crypt_stat;
 924                 if ((rc = ecryptfs_read_metadata(dentry, lower_file))) {
 925                         if (!(mount_crypt_stat->flags
 926                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 927                                 rc = -EIO;
 928                                 printk(KERN_WARNING "Attempt to read file that "
 929                                        "is not in a valid eCryptfs format, "
 930                                        "and plaintext passthrough mode is not "
 931                                        "enabled; returning -EIO\n");
 932
 933                                 mutex_unlock(&crypt_stat->cs_mutex);
 934                                 fput(lower_file);
 935                                 goto out;
 936                         }
 937                         rc = 0;
 938                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 939                         mutex_unlock(&crypt_stat->cs_mutex);
 940                         fput(lower_file);
 941                         goto out;
 942                 }
 943                 fput(lower_file);
 944         }
 945         mutex_unlock(&crypt_stat->cs_mutex);
 946         if (ia->ia_valid & ATTR_SIZE) {
 947                 ecryptfs_printk(KERN_DEBUG,
 948                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 949                                 ia->ia_valid, ATTR_SIZE);
 950                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 951                 /* ecryptfs_truncate handles resizing of the lower file */
 952                 ia->ia_valid &= ~ATTR_SIZE;
 953                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 954                                 ia->ia_valid);
 955                 if (rc < 0)
 956                         goto out;
 957         }
 958         rc = notify_change(lower_dentry, ia);
 959 out:
 960         fsstack_copy_attr_all(inode, lower_inode, NULL);
 961         return rc;
 962 }
 963
 964 int
 965 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 966                   size_t size, int flags)
 967 {
 968         int rc = 0;
 969         struct dentry *lower_dentry;
 970
 971         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 972         if (!lower_dentry->d_inode->i_op->setxattr) {
 973                 rc = -ENOSYS;
 974                 goto out;
 975         }
 976         mutex_lock(&lower_dentry->d_inode->i_mutex);
 977         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 978                                                    size, flags);
 979         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 980 out:
 981         return rc;
 982 }
 983
 984 ssize_t
 985 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 986                   size_t size)
 987 {
 988         int rc = 0;
 989         struct dentry *lower_dentry;
 990
 991         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 992         if (!lower_dentry->d_inode->i_op->getxattr) {
 993                 rc = -ENOSYS;
 994                 goto out;
 995         }
 996         mutex_lock(&lower_dentry->d_inode->i_mutex);
 997         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 998                                                    size);
 999         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1000 out:
1001         return rc;
1002 }
1003
1004 static ssize_t
1005 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1006 {
1007         int rc = 0;
1008         struct dentry *lower_dentry;
1009
1010         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1011         if (!lower_dentry->d_inode->i_op->listxattr) {
1012                 rc = -ENOSYS;
1013                 goto out;
1014         }
1015         mutex_lock(&lower_dentry->d_inode->i_mutex);
1016         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1017         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1018 out:
1019         return rc;
1020 }
1021
1022 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1023 {
1024         int rc = 0;
1025         struct dentry *lower_dentry;
1026
1027         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1028         if (!lower_dentry->d_inode->i_op->removexattr) {
1029                 rc = -ENOSYS;
1030                 goto out;
1031         }
1032         mutex_lock(&lower_dentry->d_inode->i_mutex);
1033         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1034         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1035 out:
1036         return rc;
1037 }
1038
1039 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1040 {
1041         if ((ecryptfs_inode_to_lower(inode)
1042              == (struct inode *)candidate_lower_inode))
1043                 return 1;
1044         else
1045                 return 0;
1046 }
1047
1048 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1049 {
1050         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1051         return 0;
1052 }
1053
1054 const struct inode_operations ecryptfs_symlink_iops = {
1055         .readlink = ecryptfs_readlink,
1056         .follow_link = ecryptfs_follow_link,
1057         .put_link = ecryptfs_put_link,
1058         .permission = ecryptfs_permission,
1059         .setattr = ecryptfs_setattr,
1060         .setxattr = ecryptfs_setxattr,
1061         .getxattr = ecryptfs_getxattr,
1062         .listxattr = ecryptfs_listxattr,
1063         .removexattr = ecryptfs_removexattr
1064 };
1065
1066 const struct inode_operations ecryptfs_dir_iops = {
1067         .create = ecryptfs_create,
1068         .lookup = ecryptfs_lookup,
1069         .link = ecryptfs_link,
1070         .unlink = ecryptfs_unlink,
1071         .symlink = ecryptfs_symlink,
1072         .mkdir = ecryptfs_mkdir,
1073         .rmdir = ecryptfs_rmdir,
1074         .mknod = ecryptfs_mknod,
1075         .rename = ecryptfs_rename,
1076         .permission = ecryptfs_permission,
1077         .setattr = ecryptfs_setattr,
1078         .setxattr = ecryptfs_setxattr,
1079         .getxattr = ecryptfs_getxattr,
1080         .listxattr = ecryptfs_listxattr,
1081         .removexattr = ecryptfs_removexattr
1082 };
1083
1084 const struct inode_operations ecryptfs_main_iops = {
1085         .permission = ecryptfs_permission,
1086         .setattr = ecryptfs_setattr,
1087         .setxattr = ecryptfs_setxattr,
1088         .getxattr = ecryptfs_getxattr,
1089         .listxattr = ecryptfs_listxattr,
1090         .removexattr = ecryptfs_removexattr
1091 };