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 (rc) {
 123                 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
 124                 struct ecryptfs_inode_info *inode_info =
 125                         ecryptfs_inode_to_private(ecryptfs_inode);
 126
 127                 printk(KERN_WARNING "%s: Error creating underlying file; "
 128                        "rc = [%d]; checking for existing\n", __FUNCTION__, rc);
 129                 if (inode_info) {
 130                         mutex_lock(&inode_info->lower_file_mutex);
 131                         if (!inode_info->lower_file) {
 132                                 mutex_unlock(&inode_info->lower_file_mutex);
 133                                 printk(KERN_ERR "%s: Failure to set underlying "
 134                                        "file; rc = [%d]\n", __FUNCTION__, rc);
 135                                 goto out_lock;
 136                         }
 137                         mutex_unlock(&inode_info->lower_file_mutex);
 138                 }
 139         }
 140         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 141                                 directory_inode->i_sb, 0);
 142         if (rc) {
 143                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 144                 goto out_lock;
 145         }
 146         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
 147         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
 148 out_lock:
 149         unlock_dir(lower_dir_dentry);
 150 out:
 151         return rc;
 152 }
 153
 154 /**
 155  * grow_file
 156  * @ecryptfs_dentry: the eCryptfs dentry
 157  *
 158  * This is the code which will grow the file to its correct size.
 159  */
 160 static int grow_file(struct dentry *ecryptfs_dentry)
 161 {
 162         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
 163         struct file fake_file;
 164         struct ecryptfs_file_info tmp_file_info;
 165         char zero_virt[] = { 0x00 };
 166         int rc = 0;
 167
 168         memset(&fake_file, 0, sizeof(fake_file));
 169         fake_file.f_path.dentry = ecryptfs_dentry;
 170         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 171         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 172         ecryptfs_set_file_lower(
 173                 &fake_file,
 174                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
 175         rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
 176         i_size_write(ecryptfs_inode, 0);
 177         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
 178         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
 179                 ECRYPTFS_NEW_FILE;
 180         return rc;
 181 }
 182
 183 /**
 184  * ecryptfs_initialize_file
 185  *
 186  * Cause the file to be changed from a basic empty file to an ecryptfs
 187  * file with a header and first data page.
 188  *
 189  * Returns zero on success
 190  */
 191 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 192 {
 193         struct ecryptfs_crypt_stat *crypt_stat =
 194                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
 195         int rc = 0;
 196
 197         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 198                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 199                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 200                 goto out;
 201         }
 202         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
 203         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 204         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 205         if (rc) {
 206                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 207                                 "context; rc = [%d]\n", rc);
 208                 goto out;
 209         }
 210         rc = ecryptfs_write_metadata(ecryptfs_dentry);
 211         if (rc) {
 212                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 213                 goto out;
 214         }
 215         rc = grow_file(ecryptfs_dentry);
 216         if (rc)
 217                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
 218 out:
 219         return rc;
 220 }
 221
 222 /**
 223  * ecryptfs_create
 224  * @dir: The inode of the directory in which to create the file.
 225  * @dentry: The eCryptfs dentry
 226  * @mode: The mode of the new file.
 227  * @nd: nameidata
 228  *
 229  * Creates a new file.
 230  *
 231  * Returns zero on success; non-zero on error condition
 232  */
 233 static int
 234 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 235                 int mode, struct nameidata *nd)
 236 {
 237         int rc;
 238
 239         /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
 240          * the crypt_stat->lower_file (persistent file) */
 241         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 242         if (unlikely(rc)) {
 243                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 244                                 "lower filesystem\n");
 245                 goto out;
 246         }
 247         /* At this point, a file exists on "disk"; we need to make sure
 248          * that this on disk file is prepared to be an ecryptfs file */
 249         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 250 out:
 251         return rc;
 252 }
 253
 254 /**
 255  * ecryptfs_lookup
 256  * @dir: inode
 257  * @dentry: The dentry
 258  * @nd: nameidata, may be NULL
 259  *
 260  * Find a file on disk. If the file does not exist, then we'll add it to the
 261  * dentry cache and continue on to read it from the disk.
 262  */
 263 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 264                                       struct nameidata *nd)
 265 {
 266         int rc = 0;
 267         struct dentry *lower_dir_dentry;
 268         struct dentry *lower_dentry;
 269         struct vfsmount *lower_mnt;
 270         char *encoded_name;
 271         int encoded_namelen;
 272         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 273         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 274         char *page_virt = NULL;
 275         struct inode *lower_inode;
 276         u64 file_size;
 277
 278         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 279         dentry->d_op = &ecryptfs_dops;
 280         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 281             || (dentry->d_name.len == 2
 282                 && !strcmp(dentry->d_name.name, ".."))) {
 283                 d_drop(dentry);
 284                 goto out;
 285         }
 286         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 287                                                    dentry->d_name.name,
 288                                                    dentry->d_name.len,
 289                                                    &encoded_name);
 290         if (encoded_namelen < 0) {
 291                 rc = encoded_namelen;
 292                 d_drop(dentry);
 293                 goto out;
 294         }
 295         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 296                         "= [%d]\n", encoded_name, encoded_namelen);
 297         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 298                                       encoded_namelen - 1);
 299         kfree(encoded_name);
 300         if (IS_ERR(lower_dentry)) {
 301                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 302                 rc = PTR_ERR(lower_dentry);
 303                 d_drop(dentry);
 304                 goto out;
 305         }
 306         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 307         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 308                 "d_name.name = [%s]\n", lower_dentry,
 309                 lower_dentry->d_name.name);
 310         lower_inode = lower_dentry->d_inode;
 311         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 312         BUG_ON(!atomic_read(&lower_dentry->d_count));
 313         ecryptfs_set_dentry_private(dentry,
 314                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 315                                                      GFP_KERNEL));
 316         if (!ecryptfs_dentry_to_private(dentry)) {
 317                 rc = -ENOMEM;
 318                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 319                                 "to allocate ecryptfs_dentry_info struct\n");
 320                 goto out_dput;
 321         }
 322         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 323         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 324         if (!lower_dentry->d_inode) {
 325                 /* We want to add because we couldn't find in lower */
 326                 d_add(dentry, NULL);
 327                 goto out;
 328         }
 329         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 330         if (rc) {
 331                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 332                 goto out_dput;
 333         }
 334         if (S_ISDIR(lower_inode->i_mode)) {
 335                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 336                 goto out;
 337         }
 338         if (S_ISLNK(lower_inode->i_mode)) {
 339                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 340                 goto out;
 341         }
 342         if (special_file(lower_inode->i_mode)) {
 343                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
 344                 goto out;
 345         }
 346         if (!nd) {
 347                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 348                                 "as we *think* we are about to unlink\n");
 349                 goto out;
 350         }
 351         /* Released in this function */
 352         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 353                                       GFP_USER);
 354         if (!page_virt) {
 355                 rc = -ENOMEM;
 356                 ecryptfs_printk(KERN_ERR,
 357                                 "Cannot ecryptfs_kmalloc a page\n");
 358                 goto out_dput;
 359         }
 360         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 361         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 362                 ecryptfs_set_default_sizes(crypt_stat);
 363         rc = ecryptfs_read_and_validate_header_region(page_virt,
 364                                                       dentry->d_inode);
 365         if (rc) {
 366                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 367                 if (rc) {
 368                         printk(KERN_DEBUG "Valid metadata not found in header "
 369                                "region or xattr region; treating file as "
 370                                "unencrypted\n");
 371                         rc = 0;
 372                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 373                         goto out;
 374                 }
 375                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 376         }
 377         mount_crypt_stat = &ecryptfs_superblock_to_private(
 378                 dentry->d_sb)->mount_crypt_stat;
 379         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 380                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 381                         file_size = ((crypt_stat->extent_size
 382                                       * crypt_stat->num_header_extents_at_front)
 383                                      + i_size_read(lower_dentry->d_inode));
 384                 else
 385                         file_size = i_size_read(lower_dentry->d_inode);
 386         } else {
 387                 memcpy(&file_size, page_virt, sizeof(file_size));
 388                 file_size = be64_to_cpu(file_size);
 389         }
 390         i_size_write(dentry->d_inode, (loff_t)file_size);
 391         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 392         goto out;
 393
 394 out_dput:
 395         dput(lower_dentry);
 396         d_drop(dentry);
 397 out:
 398         return ERR_PTR(rc);
 399 }
 400
 401 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 402                          struct dentry *new_dentry)
 403 {
 404         struct dentry *lower_old_dentry;
 405         struct dentry *lower_new_dentry;
 406         struct dentry *lower_dir_dentry;
 407         u64 file_size_save;
 408         int rc;
 409
 410         file_size_save = i_size_read(old_dentry->d_inode);
 411         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 412         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 413         dget(lower_old_dentry);
 414         dget(lower_new_dentry);
 415         lower_dir_dentry = lock_parent(lower_new_dentry);
 416         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 417                       lower_new_dentry);
 418         if (rc || !lower_new_dentry->d_inode)
 419                 goto out_lock;
 420         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 421         if (rc)
 422                 goto out_lock;
 423         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 424         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 425         old_dentry->d_inode->i_nlink =
 426                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 427         i_size_write(new_dentry->d_inode, file_size_save);
 428 out_lock:
 429         unlock_dir(lower_dir_dentry);
 430         dput(lower_new_dentry);
 431         dput(lower_old_dentry);
 432         d_drop(lower_old_dentry);
 433         d_drop(new_dentry);
 434         d_drop(old_dentry);
 435         return rc;
 436 }
 437
 438 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 439 {
 440         int rc = 0;
 441         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 442         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 443
 444         lock_parent(lower_dentry);
 445         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 446         if (rc) {
 447                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 448                 goto out_unlock;
 449         }
 450         fsstack_copy_attr_times(dir, lower_dir_inode);
 451         dentry->d_inode->i_nlink =
 452                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 453         dentry->d_inode->i_ctime = dir->i_ctime;
 454 out_unlock:
 455         unlock_parent(lower_dentry);
 456         return rc;
 457 }
 458
 459 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 460                             const char *symname)
 461 {
 462         int rc;
 463         struct dentry *lower_dentry;
 464         struct dentry *lower_dir_dentry;
 465         umode_t mode;
 466         char *encoded_symname;
 467         int encoded_symlen;
 468         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 469
 470         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 471         dget(lower_dentry);
 472         lower_dir_dentry = lock_parent(lower_dentry);
 473         mode = S_IALLUGO;
 474         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 475                                                   strlen(symname),
 476                                                   &encoded_symname);
 477         if (encoded_symlen < 0) {
 478                 rc = encoded_symlen;
 479                 goto out_lock;
 480         }
 481         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 482                          encoded_symname, mode);
 483         kfree(encoded_symname);
 484         if (rc || !lower_dentry->d_inode)
 485                 goto out_lock;
 486         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 487         if (rc)
 488                 goto out_lock;
 489         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 490         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 491 out_lock:
 492         unlock_dir(lower_dir_dentry);
 493         dput(lower_dentry);
 494         if (!dentry->d_inode)
 495                 d_drop(dentry);
 496         return rc;
 497 }
 498
 499 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 500 {
 501         int rc;
 502         struct dentry *lower_dentry;
 503         struct dentry *lower_dir_dentry;
 504
 505         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 506         lower_dir_dentry = lock_parent(lower_dentry);
 507         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 508         if (rc || !lower_dentry->d_inode)
 509                 goto out;
 510         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 511         if (rc)
 512                 goto out;
 513         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 514         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 515         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 516 out:
 517         unlock_dir(lower_dir_dentry);
 518         if (!dentry->d_inode)
 519                 d_drop(dentry);
 520         return rc;
 521 }
 522
 523 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 524 {
 525         struct dentry *lower_dentry;
 526         struct dentry *lower_dir_dentry;
 527         int rc;
 528
 529         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 530         dget(dentry);
 531         lower_dir_dentry = lock_parent(lower_dentry);
 532         dget(lower_dentry);
 533         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 534         dput(lower_dentry);
 535         if (!rc)
 536                 d_delete(lower_dentry);
 537         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 538         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 539         unlock_dir(lower_dir_dentry);
 540         if (!rc)
 541                 d_drop(dentry);
 542         dput(dentry);
 543         return rc;
 544 }
 545
 546 static int
 547 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 548 {
 549         int rc;
 550         struct dentry *lower_dentry;
 551         struct dentry *lower_dir_dentry;
 552
 553         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 554         lower_dir_dentry = lock_parent(lower_dentry);
 555         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 556         if (rc || !lower_dentry->d_inode)
 557                 goto out;
 558         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 559         if (rc)
 560                 goto out;
 561         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 562         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 563 out:
 564         unlock_dir(lower_dir_dentry);
 565         if (!dentry->d_inode)
 566                 d_drop(dentry);
 567         return rc;
 568 }
 569
 570 static int
 571 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 572                 struct inode *new_dir, struct dentry *new_dentry)
 573 {
 574         int rc;
 575         struct dentry *lower_old_dentry;
 576         struct dentry *lower_new_dentry;
 577         struct dentry *lower_old_dir_dentry;
 578         struct dentry *lower_new_dir_dentry;
 579
 580         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 581         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 582         dget(lower_old_dentry);
 583         dget(lower_new_dentry);
 584         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 585         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 586         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 587         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 588                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 589         if (rc)
 590                 goto out_lock;
 591         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 592         if (new_dir != old_dir)
 593                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 594 out_lock:
 595         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 596         dput(lower_new_dentry->d_parent);
 597         dput(lower_old_dentry->d_parent);
 598         dput(lower_new_dentry);
 599         dput(lower_old_dentry);
 600         return rc;
 601 }
 602
 603 static int
 604 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 605 {
 606         int rc;
 607         struct dentry *lower_dentry;
 608         char *decoded_name;
 609         char *lower_buf;
 610         mm_segment_t old_fs;
 611         struct ecryptfs_crypt_stat *crypt_stat;
 612
 613         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 614         if (!lower_dentry->d_inode->i_op ||
 615             !lower_dentry->d_inode->i_op->readlink) {
 616                 rc = -EINVAL;
 617                 goto out;
 618         }
 619         /* Released in this function */
 620         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 621         if (lower_buf == NULL) {
 622                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 623                 rc = -ENOMEM;
 624                 goto out;
 625         }
 626         old_fs = get_fs();
 627         set_fs(get_ds());
 628         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 629                         "lower_dentry->d_name.name = [%s]\n",
 630                         lower_dentry->d_name.name);
 631         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 632                                                    (char __user *)lower_buf,
 633                                                    bufsiz);
 634         set_fs(old_fs);
 635         if (rc >= 0) {
 636                 crypt_stat = NULL;
 637                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 638                                               &decoded_name);
 639                 if (rc == -ENOMEM)
 640                         goto out_free_lower_buf;
 641                 if (rc > 0) {
 642                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 643                                         "to userspace: [%*s]\n", rc,
 644                                         decoded_name);
 645                         if (copy_to_user(buf, decoded_name, rc))
 646                                 rc = -EFAULT;
 647                 }
 648                 kfree(decoded_name);
 649                 fsstack_copy_attr_atime(dentry->d_inode,
 650                                         lower_dentry->d_inode);
 651         }
 652 out_free_lower_buf:
 653         kfree(lower_buf);
 654 out:
 655         return rc;
 656 }
 657
 658 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 659 {
 660         char *buf;
 661         int len = PAGE_SIZE, rc;
 662         mm_segment_t old_fs;
 663
 664         /* Released in ecryptfs_put_link(); only release here on error */
 665         buf = kmalloc(len, GFP_KERNEL);
 666         if (!buf) {
 667                 rc = -ENOMEM;
 668                 goto out;
 669         }
 670         old_fs = get_fs();
 671         set_fs(get_ds());
 672         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 673                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 674         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 675         buf[rc] = '\0';
 676         set_fs(old_fs);
 677         if (rc < 0)
 678                 goto out_free;
 679         rc = 0;
 680         nd_set_link(nd, buf);
 681         goto out;
 682 out_free:
 683         kfree(buf);
 684 out:
 685         return ERR_PTR(rc);
 686 }
 687
 688 static void
 689 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 690 {
 691         /* Free the char* */
 692         kfree(nd_get_link(nd));
 693 }
 694
 695 /**
 696  * upper_size_to_lower_size
 697  * @crypt_stat: Crypt_stat associated with file
 698  * @upper_size: Size of the upper file
 699  *
 700  * Calculate the requried size of the lower file based on the
 701  * specified size of the upper file. This calculation is based on the
 702  * number of headers in the underlying file and the extent size.
 703  *
 704  * Returns Calculated size of the lower file.
 705  */
 706 static loff_t
 707 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 708                          loff_t upper_size)
 709 {
 710         loff_t lower_size;
 711
 712         lower_size = (crypt_stat->extent_size
 713                       * crypt_stat->num_header_extents_at_front);
 714         if (upper_size != 0) {
 715                 loff_t num_extents;
 716
 717                 num_extents = upper_size >> crypt_stat->extent_shift;
 718                 if (upper_size & ~crypt_stat->extent_mask)
 719                         num_extents++;
 720                 lower_size += (num_extents * crypt_stat->extent_size);
 721         }
 722         return lower_size;
 723 }
 724
 725 /**
 726  * ecryptfs_truncate
 727  * @dentry: The ecryptfs layer dentry
 728  * @new_length: The length to expand the file to
 729  *
 730  * Function to handle truncations modifying the size of the file. Note
 731  * that the file sizes are interpolated. When expanding, we are simply
 732  * writing strings of 0's out. When truncating, we need to modify the
 733  * underlying file size according to the page index interpolations.
 734  *
 735  * Returns zero on success; non-zero otherwise
 736  */
 737 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 738 {
 739         int rc = 0;
 740         struct inode *inode = dentry->d_inode;
 741         struct dentry *lower_dentry;
 742         struct file fake_ecryptfs_file;
 743         struct ecryptfs_crypt_stat *crypt_stat;
 744         loff_t i_size = i_size_read(inode);
 745         loff_t lower_size_before_truncate;
 746         loff_t lower_size_after_truncate;
 747
 748         if (unlikely((new_length == i_size)))
 749                 goto out;
 750         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 751         /* Set up a fake ecryptfs file, this is used to interface with
 752          * the file in the underlying filesystem so that the
 753          * truncation has an effect there as well. */
 754         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 755         fake_ecryptfs_file.f_path.dentry = dentry;
 756         /* Released at out_free: label */
 757         ecryptfs_set_file_private(&fake_ecryptfs_file,
 758                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 759                                                    GFP_KERNEL));
 760         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 761                 rc = -ENOMEM;
 762                 goto out;
 763         }
 764         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 765         ecryptfs_set_file_lower(
 766                 &fake_ecryptfs_file,
 767                 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
 768         /* Switch on growing or shrinking file */
 769         if (new_length > i_size) {
 770                 char zero[] = { 0x00 };
 771
 772                 /* Write a single 0 at the last position of the file;
 773                  * this triggers code that will fill in 0's throughout
 774                  * the intermediate portion of the previous end of the
 775                  * file and the new and of the file */
 776                 rc = ecryptfs_write(&fake_ecryptfs_file, zero,
 777                                     (new_length - 1), 1);
 778         } else { /* new_length < i_size_read(inode) */
 779                 /* We're chopping off all the pages down do the page
 780                  * in which new_length is located. Fill in the end of
 781                  * that page from (new_length & ~PAGE_CACHE_MASK) to
 782                  * PAGE_CACHE_SIZE with zeros. */
 783                 size_t num_zeros = (PAGE_CACHE_SIZE
 784                                     - (new_length & ~PAGE_CACHE_MASK));
 785
 786                 if (num_zeros) {
 787                         char *zeros_virt;
 788
 789                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 790                         if (!zeros_virt) {
 791                                 rc = -ENOMEM;
 792                                 goto out_free;
 793                         }
 794                         rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
 795                                             new_length, num_zeros);
 796                         kfree(zeros_virt);
 797                         if (rc) {
 798                                 printk(KERN_ERR "Error attempting to zero out "
 799                                        "the remainder of the end page on "
 800                                        "reducing truncate; rc = [%d]\n", rc);
 801                                 goto out_free;
 802                         }
 803                 }
 804                 vmtruncate(inode, new_length);
 805                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 806                 if (rc) {
 807                         printk(KERN_ERR "Problem with "
 808                                "ecryptfs_write_inode_size_to_metadata; "
 809                                "rc = [%d]\n", rc);
 810                         goto out_free;
 811                 }
 812                 /* We are reducing the size of the ecryptfs file, and need to
 813                  * know if we need to reduce the size of the lower file. */
 814                 lower_size_before_truncate =
 815                     upper_size_to_lower_size(crypt_stat, i_size);
 816                 lower_size_after_truncate =
 817                     upper_size_to_lower_size(crypt_stat, new_length);
 818                 if (lower_size_after_truncate < lower_size_before_truncate)
 819                         vmtruncate(lower_dentry->d_inode,
 820                                    lower_size_after_truncate);
 821         }
 822 out_free:
 823         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 824                 kmem_cache_free(ecryptfs_file_info_cache,
 825                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 826 out:
 827         return rc;
 828 }
 829
 830 static int
 831 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 832 {
 833         int rc;
 834
 835         if (nd) {
 836                 struct vfsmount *vfsmnt_save = nd->mnt;
 837                 struct dentry *dentry_save = nd->dentry;
 838
 839                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 840                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 841                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 842                 nd->mnt = vfsmnt_save;
 843                 nd->dentry = dentry_save;
 844         } else
 845                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 846         return rc;
 847 }
 848
 849 /**
 850  * ecryptfs_setattr
 851  * @dentry: dentry handle to the inode to modify
 852  * @ia: Structure with flags of what to change and values
 853  *
 854  * Updates the metadata of an inode. If the update is to the size
 855  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 856  * of both the ecryptfs inode and the lower inode.
 857  *
 858  * All other metadata changes will be passed right to the lower filesystem,
 859  * and we will just update our inode to look like the lower.
 860  */
 861 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 862 {
 863         int rc = 0;
 864         struct dentry *lower_dentry;
 865         struct inode *inode;
 866         struct inode *lower_inode;
 867         struct ecryptfs_crypt_stat *crypt_stat;
 868
 869         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 870         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 871                 ecryptfs_init_crypt_stat(crypt_stat);
 872         inode = dentry->d_inode;
 873         lower_inode = ecryptfs_inode_to_lower(inode);
 874         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 875         mutex_lock(&crypt_stat->cs_mutex);
 876         if (S_ISDIR(dentry->d_inode->i_mode))
 877                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 878         else if (S_ISREG(dentry->d_inode->i_mode)
 879                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 880                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 881                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 882
 883                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 884                         dentry->d_sb)->mount_crypt_stat;
 885                 rc = ecryptfs_read_metadata(dentry);
 886                 if (rc) {
 887                         if (!(mount_crypt_stat->flags
 888                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 889                                 rc = -EIO;
 890                                 printk(KERN_WARNING "Attempt to read file that "
 891                                        "is not in a valid eCryptfs format, "
 892                                        "and plaintext passthrough mode is not "
 893                                        "enabled; returning -EIO\n");
 894
 895                                 mutex_unlock(&crypt_stat->cs_mutex);
 896                                 goto out;
 897                         }
 898                         rc = 0;
 899                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 900                         mutex_unlock(&crypt_stat->cs_mutex);
 901                         goto out;
 902                 }
 903         }
 904         mutex_unlock(&crypt_stat->cs_mutex);
 905         if (ia->ia_valid & ATTR_SIZE) {
 906                 ecryptfs_printk(KERN_DEBUG,
 907                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 908                                 ia->ia_valid, ATTR_SIZE);
 909                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 910                 /* ecryptfs_truncate handles resizing of the lower file */
 911                 ia->ia_valid &= ~ATTR_SIZE;
 912                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 913                                 ia->ia_valid);
 914                 if (rc < 0)
 915                         goto out;
 916         }
 917
 918         /*
 919          * mode change is for clearing setuid/setgid bits. Allow lower fs
 920          * to interpret this in its own way.
 921          */
 922         if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 923                 ia->ia_valid &= ~ATTR_MODE;
 924
 925         rc = notify_change(lower_dentry, ia);
 926 out:
 927         fsstack_copy_attr_all(inode, lower_inode, NULL);
 928         return rc;
 929 }
 930
 931 int
 932 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 933                   size_t size, int flags)
 934 {
 935         int rc = 0;
 936         struct dentry *lower_dentry;
 937
 938         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 939         if (!lower_dentry->d_inode->i_op->setxattr) {
 940                 rc = -ENOSYS;
 941                 goto out;
 942         }
 943         mutex_lock(&lower_dentry->d_inode->i_mutex);
 944         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 945                                                    size, flags);
 946         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 947 out:
 948         return rc;
 949 }
 950
 951 ssize_t
 952 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
 953                         void *value, size_t size)
 954 {
 955         int rc = 0;
 956
 957         if (!lower_dentry->d_inode->i_op->getxattr) {
 958                 rc = -ENOSYS;
 959                 goto out;
 960         }
 961         mutex_lock(&lower_dentry->d_inode->i_mutex);
 962         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 963                                                    size);
 964         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 965 out:
 966         return rc;
 967 }
 968
 969 ssize_t
 970 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 971                   size_t size)
 972 {
 973         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
 974                                        value, size);
 975 }
 976
 977 static ssize_t
 978 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 979 {
 980         int rc = 0;
 981         struct dentry *lower_dentry;
 982
 983         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 984         if (!lower_dentry->d_inode->i_op->listxattr) {
 985                 rc = -ENOSYS;
 986                 goto out;
 987         }
 988         mutex_lock(&lower_dentry->d_inode->i_mutex);
 989         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
 990         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 991 out:
 992         return rc;
 993 }
 994
 995 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
 996 {
 997         int rc = 0;
 998         struct dentry *lower_dentry;
 999
1000         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1001         if (!lower_dentry->d_inode->i_op->removexattr) {
1002                 rc = -ENOSYS;
1003                 goto out;
1004         }
1005         mutex_lock(&lower_dentry->d_inode->i_mutex);
1006         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1007         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1008 out:
1009         return rc;
1010 }
1011
1012 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1013 {
1014         if ((ecryptfs_inode_to_lower(inode)
1015              == (struct inode *)candidate_lower_inode))
1016                 return 1;
1017         else
1018                 return 0;
1019 }
1020
1021 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1022 {
1023         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1024         return 0;
1025 }
1026
1027 const struct inode_operations ecryptfs_symlink_iops = {
1028         .readlink = ecryptfs_readlink,
1029         .follow_link = ecryptfs_follow_link,
1030         .put_link = ecryptfs_put_link,
1031         .permission = ecryptfs_permission,
1032         .setattr = ecryptfs_setattr,
1033         .setxattr = ecryptfs_setxattr,
1034         .getxattr = ecryptfs_getxattr,
1035         .listxattr = ecryptfs_listxattr,
1036         .removexattr = ecryptfs_removexattr
1037 };
1038
1039 const struct inode_operations ecryptfs_dir_iops = {
1040         .create = ecryptfs_create,
1041         .lookup = ecryptfs_lookup,
1042         .link = ecryptfs_link,
1043         .unlink = ecryptfs_unlink,
1044         .symlink = ecryptfs_symlink,
1045         .mkdir = ecryptfs_mkdir,
1046         .rmdir = ecryptfs_rmdir,
1047         .mknod = ecryptfs_mknod,
1048         .rename = ecryptfs_rename,
1049         .permission = ecryptfs_permission,
1050         .setattr = ecryptfs_setattr,
1051         .setxattr = ecryptfs_setxattr,
1052         .getxattr = ecryptfs_getxattr,
1053         .listxattr = ecryptfs_listxattr,
1054         .removexattr = ecryptfs_removexattr
1055 };
1056
1057 const struct inode_operations ecryptfs_main_iops = {
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 };