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 <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  * @dentry: New file's dentry
  56  * @mode: The mode of the new file
  57  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  58  *
  59  * Creates the file in the lower file system.
  60  *
  61  * Returns zero on success; non-zero on error condition
  62  */
  63 static int
  64 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
  65                                 struct dentry *dentry, int mode,
  66                                 struct nameidata *nd)
  67 {
  68         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  69         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  70         struct dentry *dentry_save;
  71         struct vfsmount *vfsmount_save;
  72         int rc;
  73
  74         dentry_save = nd->path.dentry;
  75         vfsmount_save = nd->path.mnt;
  76         nd->path.dentry = lower_dentry;
  77         nd->path.mnt = lower_mnt;
  78         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
  79         nd->path.dentry = dentry_save;
  80         nd->path.mnt = vfsmount_save;
  81         return rc;
  82 }
  83
  84 /**
  85  * ecryptfs_do_create
  86  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
  87  * @ecryptfs_dentry: New file's dentry in ecryptfs
  88  * @mode: The mode of the new file
  89  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  90  *
  91  * Creates the underlying file and the eCryptfs inode which will link to
  92  * it. It will also update the eCryptfs directory inode to mimic the
  93  * stat of the lower directory inode.
  94  *
  95  * Returns zero on success; non-zero on error condition
  96  */
  97 static int
  98 ecryptfs_do_create(struct inode *directory_inode,
  99                    struct dentry *ecryptfs_dentry, int mode,
 100                    struct nameidata *nd)
 101 {
 102         int rc;
 103         struct dentry *lower_dentry;
 104         struct dentry *lower_dir_dentry;
 105
 106         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 107         lower_dir_dentry = lock_parent(lower_dentry);
 108         if (IS_ERR(lower_dir_dentry)) {
 109                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 110                                 "dentry\n");
 111                 rc = PTR_ERR(lower_dir_dentry);
 112                 goto out;
 113         }
 114         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 115                                              ecryptfs_dentry, mode, nd);
 116         if (rc) {
 117                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 118                        "rc = [%d]\n", __func__, rc);
 119                 goto out_lock;
 120         }
 121         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 122                                 directory_inode->i_sb, 0);
 123         if (rc) {
 124                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 125                 goto out_lock;
 126         }
 127         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
 128         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
 129 out_lock:
 130         unlock_dir(lower_dir_dentry);
 131 out:
 132         return rc;
 133 }
 134
 135 /**
 136  * grow_file
 137  * @ecryptfs_dentry: the eCryptfs dentry
 138  *
 139  * This is the code which will grow the file to its correct size.
 140  */
 141 static int grow_file(struct dentry *ecryptfs_dentry)
 142 {
 143         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
 144         struct file fake_file;
 145         struct ecryptfs_file_info tmp_file_info;
 146         char zero_virt[] = { 0x00 };
 147         int rc = 0;
 148
 149         memset(&fake_file, 0, sizeof(fake_file));
 150         fake_file.f_path.dentry = ecryptfs_dentry;
 151         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 152         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 153         ecryptfs_set_file_lower(
 154                 &fake_file,
 155                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
 156         rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
 157         i_size_write(ecryptfs_inode, 0);
 158         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
 159         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
 160                 ECRYPTFS_NEW_FILE;
 161         return rc;
 162 }
 163
 164 /**
 165  * ecryptfs_initialize_file
 166  *
 167  * Cause the file to be changed from a basic empty file to an ecryptfs
 168  * file with a header and first data page.
 169  *
 170  * Returns zero on success
 171  */
 172 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 173 {
 174         struct ecryptfs_crypt_stat *crypt_stat =
 175                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
 176         int rc = 0;
 177
 178         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 179                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 180                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 181                 goto out;
 182         }
 183         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
 184         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 185         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 186         if (rc) {
 187                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 188                                 "context; rc = [%d]\n", rc);
 189                 goto out;
 190         }
 191         if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
 192                 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
 193                 if (rc) {
 194                         printk(KERN_ERR "%s: Error attempting to initialize "
 195                                "the persistent file for the dentry with name "
 196                                "[%s]; rc = [%d]\n", __func__,
 197                                ecryptfs_dentry->d_name.name, rc);
 198                         goto out;
 199                 }
 200         }
 201         rc = ecryptfs_write_metadata(ecryptfs_dentry);
 202         if (rc) {
 203                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 204                 goto out;
 205         }
 206         rc = grow_file(ecryptfs_dentry);
 207         if (rc)
 208                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
 209 out:
 210         return rc;
 211 }
 212
 213 /**
 214  * ecryptfs_create
 215  * @dir: The inode of the directory in which to create the file.
 216  * @dentry: The eCryptfs dentry
 217  * @mode: The mode of the new file.
 218  * @nd: nameidata
 219  *
 220  * Creates a new file.
 221  *
 222  * Returns zero on success; non-zero on error condition
 223  */
 224 static int
 225 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 226                 int mode, struct nameidata *nd)
 227 {
 228         int rc;
 229
 230         /* ecryptfs_do_create() calls ecryptfs_interpose() */
 231         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 232         if (unlikely(rc)) {
 233                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 234                                 "lower filesystem\n");
 235                 goto out;
 236         }
 237         /* At this point, a file exists on "disk"; we need to make sure
 238          * that this on disk file is prepared to be an ecryptfs file */
 239         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 240 out:
 241         return rc;
 242 }
 243
 244 /**
 245  * ecryptfs_lookup_and_interpose_lower - Perform a lookup
 246  */
 247 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
 248                                         struct dentry *lower_dentry,
 249                                         struct inode *ecryptfs_dir_inode,
 250                                         struct nameidata *ecryptfs_nd)
 251 {
 252         struct dentry *lower_dir_dentry;
 253         struct vfsmount *lower_mnt;
 254         struct inode *lower_inode;
 255         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 256         struct ecryptfs_crypt_stat *crypt_stat;
 257         char *page_virt = NULL;
 258         u64 file_size;
 259         int rc = 0;
 260
 261         lower_dir_dentry = lower_dentry->d_parent;
 262         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
 263                                    ecryptfs_dentry->d_parent));
 264         lower_inode = lower_dentry->d_inode;
 265         fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
 266         BUG_ON(!atomic_read(&lower_dentry->d_count));
 267         ecryptfs_set_dentry_private(ecryptfs_dentry,
 268                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 269                                                      GFP_KERNEL));
 270         if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
 271                 rc = -ENOMEM;
 272                 printk(KERN_ERR "%s: Out of memory whilst attempting "
 273                        "to allocate ecryptfs_dentry_info struct\n",
 274                         __func__);
 275                 goto out_dput;
 276         }
 277         ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
 278         ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
 279         if (!lower_dentry->d_inode) {
 280                 /* We want to add because we couldn't find in lower */
 281                 d_add(ecryptfs_dentry, NULL);
 282                 goto out;
 283         }
 284         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 285                                 ecryptfs_dir_inode->i_sb, 1);
 286         if (rc) {
 287                 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
 288                        __func__, rc);
 289                 goto out;
 290         }
 291         if (S_ISDIR(lower_inode->i_mode))
 292                 goto out;
 293         if (S_ISLNK(lower_inode->i_mode))
 294                 goto out;
 295         if (special_file(lower_inode->i_mode))
 296                 goto out;
 297         if (!ecryptfs_nd)
 298                 goto out;
 299         /* Released in this function */
 300         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
 301         if (!page_virt) {
 302                 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
 303                        __func__);
 304                 rc = -ENOMEM;
 305                 goto out;
 306         }
 307         if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
 308                 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
 309                 if (rc) {
 310                         printk(KERN_ERR "%s: Error attempting to initialize "
 311                                "the persistent file for the dentry with name "
 312                                "[%s]; rc = [%d]\n", __func__,
 313                                ecryptfs_dentry->d_name.name, rc);
 314                         goto out_free_kmem;
 315                 }
 316         }
 317         crypt_stat = &ecryptfs_inode_to_private(
 318                                         ecryptfs_dentry->d_inode)->crypt_stat;
 319         /* TODO: lock for crypt_stat comparison */
 320         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 321                         ecryptfs_set_default_sizes(crypt_stat);
 322         rc = ecryptfs_read_and_validate_header_region(page_virt,
 323                                                       ecryptfs_dentry->d_inode);
 324         if (rc) {
 325                 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
 326                                                              ecryptfs_dentry);
 327                 if (rc) {
 328                         rc = 0;
 329                         goto out_free_kmem;
 330                 }
 331                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 332         }
 333         mount_crypt_stat = &ecryptfs_superblock_to_private(
 334                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 335         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 336                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 337                         file_size = (crypt_stat->num_header_bytes_at_front
 338                                      + i_size_read(lower_dentry->d_inode));
 339                 else
 340                         file_size = i_size_read(lower_dentry->d_inode);
 341         } else {
 342                 file_size = get_unaligned_be64(page_virt);
 343         }
 344         i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
 345 out_free_kmem:
 346         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 347         goto out;
 348 out_dput:
 349         dput(lower_dentry);
 350         d_drop(ecryptfs_dentry);
 351 out:
 352         return rc;
 353 }
 354
 355 /**
 356  * ecryptfs_lookup
 357  * @ecryptfs_dir_inode: The eCryptfs directory inode
 358  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 359  * @ecryptfs_nd: nameidata; may be NULL
 360  *
 361  * Find a file on disk. If the file does not exist, then we'll add it to the
 362  * dentry cache and continue on to read it from the disk.
 363  */
 364 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 365                                       struct dentry *ecryptfs_dentry,
 366                                       struct nameidata *ecryptfs_nd)
 367 {
 368         char *encrypted_and_encoded_name = NULL;
 369         size_t encrypted_and_encoded_name_size;
 370         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 371         struct dentry *lower_dir_dentry, *lower_dentry;
 372         int rc = 0;
 373
 374         ecryptfs_dentry->d_op = &ecryptfs_dops;
 375         if ((ecryptfs_dentry->d_name.len == 1
 376              && !strcmp(ecryptfs_dentry->d_name.name, "."))
 377             || (ecryptfs_dentry->d_name.len == 2
 378                 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
 379                 goto out_d_drop;
 380         }
 381         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 382         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
 383                                       lower_dir_dentry,
 384                                       ecryptfs_dentry->d_name.len);
 385         if (IS_ERR(lower_dentry)) {
 386                 rc = PTR_ERR(lower_dentry);
 387                 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
 388                        "lower_dentry = [%s]\n", __func__, rc,
 389                        ecryptfs_dentry->d_name.name);
 390                 goto out_d_drop;
 391         }
 392         if (lower_dentry->d_inode)
 393                 goto lookup_and_interpose;
 394         mount_crypt_stat = &ecryptfs_superblock_to_private(
 395                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 396         if (!(mount_crypt_stat
 397             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
 398                 goto lookup_and_interpose;
 399         dput(lower_dentry);
 400         rc = ecryptfs_encrypt_and_encode_filename(
 401                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
 402                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
 403                 ecryptfs_dentry->d_name.len);
 404         if (rc) {
 405                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 406                        "filename; rc = [%d]\n", __func__, rc);
 407                 goto out_d_drop;
 408         }
 409         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
 410                                       lower_dir_dentry,
 411                                       encrypted_and_encoded_name_size - 1);
 412         if (IS_ERR(lower_dentry)) {
 413                 rc = PTR_ERR(lower_dentry);
 414                 printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
 415                        "lower_dentry = [%s]\n", __func__, rc,
 416                        encrypted_and_encoded_name);
 417                 goto out_d_drop;
 418         }
 419 lookup_and_interpose:
 420         rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
 421                                                  ecryptfs_dir_inode,
 422                                                  ecryptfs_nd);
 423         goto out;
 424 out_d_drop:
 425         d_drop(ecryptfs_dentry);
 426 out:
 427         kfree(encrypted_and_encoded_name);
 428         return ERR_PTR(rc);
 429 }
 430
 431 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 432                          struct dentry *new_dentry)
 433 {
 434         struct dentry *lower_old_dentry;
 435         struct dentry *lower_new_dentry;
 436         struct dentry *lower_dir_dentry;
 437         u64 file_size_save;
 438         int rc;
 439
 440         file_size_save = i_size_read(old_dentry->d_inode);
 441         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 442         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 443         dget(lower_old_dentry);
 444         dget(lower_new_dentry);
 445         lower_dir_dentry = lock_parent(lower_new_dentry);
 446         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 447                       lower_new_dentry);
 448         if (rc || !lower_new_dentry->d_inode)
 449                 goto out_lock;
 450         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 451         if (rc)
 452                 goto out_lock;
 453         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 454         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 455         old_dentry->d_inode->i_nlink =
 456                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 457         i_size_write(new_dentry->d_inode, file_size_save);
 458 out_lock:
 459         unlock_dir(lower_dir_dentry);
 460         dput(lower_new_dentry);
 461         dput(lower_old_dentry);
 462         d_drop(lower_old_dentry);
 463         d_drop(new_dentry);
 464         d_drop(old_dentry);
 465         return rc;
 466 }
 467
 468 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 469 {
 470         int rc = 0;
 471         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 472         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 473         struct dentry *lower_dir_dentry;
 474
 475         lower_dir_dentry = lock_parent(lower_dentry);
 476         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 477         if (rc) {
 478                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 479                 goto out_unlock;
 480         }
 481         fsstack_copy_attr_times(dir, lower_dir_inode);
 482         dentry->d_inode->i_nlink =
 483                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 484         dentry->d_inode->i_ctime = dir->i_ctime;
 485         d_drop(dentry);
 486 out_unlock:
 487         unlock_dir(lower_dir_dentry);
 488         return rc;
 489 }
 490
 491 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 492                             const char *symname)
 493 {
 494         int rc;
 495         struct dentry *lower_dentry;
 496         struct dentry *lower_dir_dentry;
 497         char *encoded_symname;
 498         size_t encoded_symlen;
 499         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 500
 501         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 502         dget(lower_dentry);
 503         lower_dir_dentry = lock_parent(lower_dentry);
 504         mount_crypt_stat = &ecryptfs_superblock_to_private(
 505                 dir->i_sb)->mount_crypt_stat;
 506         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 507                                                   &encoded_symlen,
 508                                                   NULL,
 509                                                   mount_crypt_stat, symname,
 510                                                   strlen(symname));
 511         if (rc)
 512                 goto out_lock;
 513         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 514                          encoded_symname);
 515         kfree(encoded_symname);
 516         if (rc || !lower_dentry->d_inode)
 517                 goto out_lock;
 518         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 519         if (rc)
 520                 goto out_lock;
 521         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 522         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 523 out_lock:
 524         unlock_dir(lower_dir_dentry);
 525         dput(lower_dentry);
 526         if (!dentry->d_inode)
 527                 d_drop(dentry);
 528         return rc;
 529 }
 530
 531 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 532 {
 533         int rc;
 534         struct dentry *lower_dentry;
 535         struct dentry *lower_dir_dentry;
 536
 537         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 538         lower_dir_dentry = lock_parent(lower_dentry);
 539         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 540         if (rc || !lower_dentry->d_inode)
 541                 goto out;
 542         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 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         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 548 out:
 549         unlock_dir(lower_dir_dentry);
 550         if (!dentry->d_inode)
 551                 d_drop(dentry);
 552         return rc;
 553 }
 554
 555 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 556 {
 557         struct dentry *lower_dentry;
 558         struct dentry *lower_dir_dentry;
 559         int rc;
 560
 561         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 562         dget(dentry);
 563         lower_dir_dentry = lock_parent(lower_dentry);
 564         dget(lower_dentry);
 565         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 566         dput(lower_dentry);
 567         if (!rc)
 568                 d_delete(lower_dentry);
 569         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 570         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 571         unlock_dir(lower_dir_dentry);
 572         if (!rc)
 573                 d_drop(dentry);
 574         dput(dentry);
 575         return rc;
 576 }
 577
 578 static int
 579 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 580 {
 581         int rc;
 582         struct dentry *lower_dentry;
 583         struct dentry *lower_dir_dentry;
 584
 585         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 586         lower_dir_dentry = lock_parent(lower_dentry);
 587         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 588         if (rc || !lower_dentry->d_inode)
 589                 goto out;
 590         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 591         if (rc)
 592                 goto out;
 593         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 594         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 595 out:
 596         unlock_dir(lower_dir_dentry);
 597         if (!dentry->d_inode)
 598                 d_drop(dentry);
 599         return rc;
 600 }
 601
 602 static int
 603 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 604                 struct inode *new_dir, struct dentry *new_dentry)
 605 {
 606         int rc;
 607         struct dentry *lower_old_dentry;
 608         struct dentry *lower_new_dentry;
 609         struct dentry *lower_old_dir_dentry;
 610         struct dentry *lower_new_dir_dentry;
 611
 612         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 613         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 614         dget(lower_old_dentry);
 615         dget(lower_new_dentry);
 616         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 617         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 618         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 619         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 620                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 621         if (rc)
 622                 goto out_lock;
 623         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 624         if (new_dir != old_dir)
 625                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 626 out_lock:
 627         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 628         dput(lower_new_dentry->d_parent);
 629         dput(lower_old_dentry->d_parent);
 630         dput(lower_new_dentry);
 631         dput(lower_old_dentry);
 632         return rc;
 633 }
 634
 635 static int
 636 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
 637 {
 638         char *lower_buf;
 639         struct dentry *lower_dentry;
 640         struct ecryptfs_crypt_stat *crypt_stat;
 641         char *plaintext_name;
 642         size_t plaintext_name_size;
 643         mm_segment_t old_fs;
 644         int rc;
 645
 646         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 647         if (!lower_dentry->d_inode->i_op->readlink) {
 648                 rc = -EINVAL;
 649                 goto out;
 650         }
 651         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 652         /* Released in this function */
 653         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 654         if (lower_buf == NULL) {
 655                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
 656                        "kmalloc [%d] bytes\n", __func__, bufsiz);
 657                 rc = -ENOMEM;
 658                 goto out;
 659         }
 660         old_fs = get_fs();
 661         set_fs(get_ds());
 662         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 663                                                    (char __user *)lower_buf,
 664                                                    bufsiz);
 665         set_fs(old_fs);
 666         if (rc >= 0) {
 667                 rc = ecryptfs_decode_and_decrypt_filename(&plaintext_name,
 668                                                           &plaintext_name_size,
 669                                                           dentry, lower_buf,
 670                                                           rc);
 671                 if (rc) {
 672                         printk(KERN_ERR "%s: Error attempting to decode and "
 673                                "decrypt filename; rc = [%d]\n", __func__,
 674                                 rc);
 675                         goto out_free_lower_buf;
 676                 }
 677                 rc = copy_to_user(buf, plaintext_name, plaintext_name_size);
 678                 if (rc)
 679                         rc = -EFAULT;
 680                 else
 681                         rc = plaintext_name_size;
 682                 kfree(plaintext_name);
 683                 fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode);
 684         }
 685 out_free_lower_buf:
 686         kfree(lower_buf);
 687 out:
 688         return rc;
 689 }
 690
 691 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 692 {
 693         char *buf;
 694         int len = PAGE_SIZE, rc;
 695         mm_segment_t old_fs;
 696
 697         /* Released in ecryptfs_put_link(); only release here on error */
 698         buf = kmalloc(len, GFP_KERNEL);
 699         if (!buf) {
 700                 rc = -ENOMEM;
 701                 goto out;
 702         }
 703         old_fs = get_fs();
 704         set_fs(get_ds());
 705         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 706         set_fs(old_fs);
 707         if (rc < 0)
 708                 goto out_free;
 709         else
 710                 buf[rc] = '\0';
 711         rc = 0;
 712         nd_set_link(nd, buf);
 713         goto out;
 714 out_free:
 715         kfree(buf);
 716 out:
 717         return ERR_PTR(rc);
 718 }
 719
 720 static void
 721 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 722 {
 723         /* Free the char* */
 724         kfree(nd_get_link(nd));
 725 }
 726
 727 /**
 728  * upper_size_to_lower_size
 729  * @crypt_stat: Crypt_stat associated with file
 730  * @upper_size: Size of the upper file
 731  *
 732  * Calculate the required size of the lower file based on the
 733  * specified size of the upper file. This calculation is based on the
 734  * number of headers in the underlying file and the extent size.
 735  *
 736  * Returns Calculated size of the lower file.
 737  */
 738 static loff_t
 739 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 740                          loff_t upper_size)
 741 {
 742         loff_t lower_size;
 743
 744         lower_size = crypt_stat->num_header_bytes_at_front;
 745         if (upper_size != 0) {
 746                 loff_t num_extents;
 747
 748                 num_extents = upper_size >> crypt_stat->extent_shift;
 749                 if (upper_size & ~crypt_stat->extent_mask)
 750                         num_extents++;
 751                 lower_size += (num_extents * crypt_stat->extent_size);
 752         }
 753         return lower_size;
 754 }
 755
 756 /**
 757  * ecryptfs_truncate
 758  * @dentry: The ecryptfs layer dentry
 759  * @new_length: The length to expand the file to
 760  *
 761  * Function to handle truncations modifying the size of the file. Note
 762  * that the file sizes are interpolated. When expanding, we are simply
 763  * writing strings of 0's out. When truncating, we need to modify the
 764  * underlying file size according to the page index interpolations.
 765  *
 766  * Returns zero on success; non-zero otherwise
 767  */
 768 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 769 {
 770         int rc = 0;
 771         struct inode *inode = dentry->d_inode;
 772         struct dentry *lower_dentry;
 773         struct file fake_ecryptfs_file;
 774         struct ecryptfs_crypt_stat *crypt_stat;
 775         loff_t i_size = i_size_read(inode);
 776         loff_t lower_size_before_truncate;
 777         loff_t lower_size_after_truncate;
 778
 779         if (unlikely((new_length == i_size)))
 780                 goto out;
 781         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 782         /* Set up a fake ecryptfs file, this is used to interface with
 783          * the file in the underlying filesystem so that the
 784          * truncation has an effect there as well. */
 785         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 786         fake_ecryptfs_file.f_path.dentry = dentry;
 787         /* Released at out_free: label */
 788         ecryptfs_set_file_private(&fake_ecryptfs_file,
 789                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 790                                                    GFP_KERNEL));
 791         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 792                 rc = -ENOMEM;
 793                 goto out;
 794         }
 795         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 796         ecryptfs_set_file_lower(
 797                 &fake_ecryptfs_file,
 798                 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
 799         /* Switch on growing or shrinking file */
 800         if (new_length > i_size) {
 801                 char zero[] = { 0x00 };
 802
 803                 /* Write a single 0 at the last position of the file;
 804                  * this triggers code that will fill in 0's throughout
 805                  * the intermediate portion of the previous end of the
 806                  * file and the new and of the file */
 807                 rc = ecryptfs_write(&fake_ecryptfs_file, zero,
 808                                     (new_length - 1), 1);
 809         } else { /* new_length < i_size_read(inode) */
 810                 /* We're chopping off all the pages down do the page
 811                  * in which new_length is located. Fill in the end of
 812                  * that page from (new_length & ~PAGE_CACHE_MASK) to
 813                  * PAGE_CACHE_SIZE with zeros. */
 814                 size_t num_zeros = (PAGE_CACHE_SIZE
 815                                     - (new_length & ~PAGE_CACHE_MASK));
 816
 817                 if (num_zeros) {
 818                         char *zeros_virt;
 819
 820                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 821                         if (!zeros_virt) {
 822                                 rc = -ENOMEM;
 823                                 goto out_free;
 824                         }
 825                         rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
 826                                             new_length, num_zeros);
 827                         kfree(zeros_virt);
 828                         if (rc) {
 829                                 printk(KERN_ERR "Error attempting to zero out "
 830                                        "the remainder of the end page on "
 831                                        "reducing truncate; rc = [%d]\n", rc);
 832                                 goto out_free;
 833                         }
 834                 }
 835                 vmtruncate(inode, new_length);
 836                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 837                 if (rc) {
 838                         printk(KERN_ERR "Problem with "
 839                                "ecryptfs_write_inode_size_to_metadata; "
 840                                "rc = [%d]\n", rc);
 841                         goto out_free;
 842                 }
 843                 /* We are reducing the size of the ecryptfs file, and need to
 844                  * know if we need to reduce the size of the lower file. */
 845                 lower_size_before_truncate =
 846                     upper_size_to_lower_size(crypt_stat, i_size);
 847                 lower_size_after_truncate =
 848                     upper_size_to_lower_size(crypt_stat, new_length);
 849                 if (lower_size_after_truncate < lower_size_before_truncate)
 850                         vmtruncate(lower_dentry->d_inode,
 851                                    lower_size_after_truncate);
 852         }
 853 out_free:
 854         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 855                 kmem_cache_free(ecryptfs_file_info_cache,
 856                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 857 out:
 858         return rc;
 859 }
 860
 861 static int
 862 ecryptfs_permission(struct inode *inode, int mask)
 863 {
 864         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 865 }
 866
 867 /**
 868  * ecryptfs_setattr
 869  * @dentry: dentry handle to the inode to modify
 870  * @ia: Structure with flags of what to change and values
 871  *
 872  * Updates the metadata of an inode. If the update is to the size
 873  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 874  * of both the ecryptfs inode and the lower inode.
 875  *
 876  * All other metadata changes will be passed right to the lower filesystem,
 877  * and we will just update our inode to look like the lower.
 878  */
 879 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 880 {
 881         int rc = 0;
 882         struct dentry *lower_dentry;
 883         struct inode *inode;
 884         struct inode *lower_inode;
 885         struct ecryptfs_crypt_stat *crypt_stat;
 886
 887         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 888         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 889                 ecryptfs_init_crypt_stat(crypt_stat);
 890         inode = dentry->d_inode;
 891         lower_inode = ecryptfs_inode_to_lower(inode);
 892         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 893         mutex_lock(&crypt_stat->cs_mutex);
 894         if (S_ISDIR(dentry->d_inode->i_mode))
 895                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 896         else if (S_ISREG(dentry->d_inode->i_mode)
 897                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 898                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 899                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 900
 901                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 902                         dentry->d_sb)->mount_crypt_stat;
 903                 rc = ecryptfs_read_metadata(dentry);
 904                 if (rc) {
 905                         if (!(mount_crypt_stat->flags
 906                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 907                                 rc = -EIO;
 908                                 printk(KERN_WARNING "Either the lower file "
 909                                        "is not in a valid eCryptfs format, "
 910                                        "or the key could not be retrieved. "
 911                                        "Plaintext passthrough mode is not "
 912                                        "enabled; returning -EIO\n");
 913                                 mutex_unlock(&crypt_stat->cs_mutex);
 914                                 goto out;
 915                         }
 916                         rc = 0;
 917                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 918                         mutex_unlock(&crypt_stat->cs_mutex);
 919                         goto out;
 920                 }
 921         }
 922         mutex_unlock(&crypt_stat->cs_mutex);
 923         if (ia->ia_valid & ATTR_SIZE) {
 924                 ecryptfs_printk(KERN_DEBUG,
 925                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 926                                 ia->ia_valid, ATTR_SIZE);
 927                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 928                 /* ecryptfs_truncate handles resizing of the lower file */
 929                 ia->ia_valid &= ~ATTR_SIZE;
 930                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 931                                 ia->ia_valid);
 932                 if (rc < 0)
 933                         goto out;
 934         }
 935
 936         /*
 937          * mode change is for clearing setuid/setgid bits. Allow lower fs
 938          * to interpret this in its own way.
 939          */
 940         if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 941                 ia->ia_valid &= ~ATTR_MODE;
 942
 943         mutex_lock(&lower_dentry->d_inode->i_mutex);
 944         rc = notify_change(lower_dentry, ia);
 945         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 946 out:
 947         fsstack_copy_attr_all(inode, lower_inode, NULL);
 948         return rc;
 949 }
 950
 951 int
 952 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 953                   size_t size, int flags)
 954 {
 955         int rc = 0;
 956         struct dentry *lower_dentry;
 957
 958         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 959         if (!lower_dentry->d_inode->i_op->setxattr) {
 960                 rc = -ENOSYS;
 961                 goto out;
 962         }
 963         mutex_lock(&lower_dentry->d_inode->i_mutex);
 964         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 965                                                    size, flags);
 966         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 967 out:
 968         return rc;
 969 }
 970
 971 ssize_t
 972 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
 973                         void *value, size_t size)
 974 {
 975         int rc = 0;
 976
 977         if (!lower_dentry->d_inode->i_op->getxattr) {
 978                 rc = -ENOSYS;
 979                 goto out;
 980         }
 981         mutex_lock(&lower_dentry->d_inode->i_mutex);
 982         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 983                                                    size);
 984         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 985 out:
 986         return rc;
 987 }
 988
 989 static ssize_t
 990 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 991                   size_t size)
 992 {
 993         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
 994                                        value, size);
 995 }
 996
 997 static ssize_t
 998 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 999 {
1000         int rc = 0;
1001         struct dentry *lower_dentry;
1002
1003         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1004         if (!lower_dentry->d_inode->i_op->listxattr) {
1005                 rc = -ENOSYS;
1006                 goto out;
1007         }
1008         mutex_lock(&lower_dentry->d_inode->i_mutex);
1009         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1010         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1011 out:
1012         return rc;
1013 }
1014
1015 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1016 {
1017         int rc = 0;
1018         struct dentry *lower_dentry;
1019
1020         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1021         if (!lower_dentry->d_inode->i_op->removexattr) {
1022                 rc = -ENOSYS;
1023                 goto out;
1024         }
1025         mutex_lock(&lower_dentry->d_inode->i_mutex);
1026         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1027         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1028 out:
1029         return rc;
1030 }
1031
1032 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1033 {
1034         if ((ecryptfs_inode_to_lower(inode)
1035              == (struct inode *)candidate_lower_inode))
1036                 return 1;
1037         else
1038                 return 0;
1039 }
1040
1041 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1042 {
1043         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1044         return 0;
1045 }
1046
1047 const struct inode_operations ecryptfs_symlink_iops = {
1048         .readlink = ecryptfs_readlink,
1049         .follow_link = ecryptfs_follow_link,
1050         .put_link = ecryptfs_put_link,
1051         .permission = ecryptfs_permission,
1052         .setattr = ecryptfs_setattr,
1053         .setxattr = ecryptfs_setxattr,
1054         .getxattr = ecryptfs_getxattr,
1055         .listxattr = ecryptfs_listxattr,
1056         .removexattr = ecryptfs_removexattr
1057 };
1058
1059 const struct inode_operations ecryptfs_dir_iops = {
1060         .create = ecryptfs_create,
1061         .lookup = ecryptfs_lookup,
1062         .link = ecryptfs_link,
1063         .unlink = ecryptfs_unlink,
1064         .symlink = ecryptfs_symlink,
1065         .mkdir = ecryptfs_mkdir,
1066         .rmdir = ecryptfs_rmdir,
1067         .mknod = ecryptfs_mknod,
1068         .rename = ecryptfs_rename,
1069         .permission = ecryptfs_permission,
1070         .setattr = ecryptfs_setattr,
1071         .setxattr = ecryptfs_setxattr,
1072         .getxattr = ecryptfs_getxattr,
1073         .listxattr = ecryptfs_listxattr,
1074         .removexattr = ecryptfs_removexattr
1075 };
1076
1077 const struct inode_operations ecryptfs_main_iops = {
1078         .permission = ecryptfs_permission,
1079         .setattr = ecryptfs_setattr,
1080         .setxattr = ecryptfs_setxattr,
1081         .getxattr = ecryptfs_getxattr,
1082         .listxattr = ecryptfs_listxattr,
1083         .removexattr = ecryptfs_removexattr
1084 };