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 (special_file(lower_inode->i_mode)) {
 357                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
 358                 goto out;
 359         }
 360         if (!nd) {
 361                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 362                                 "as we *think* we are about to unlink\n");
 363                 goto out;
 364         }
 365         /* Released in this function */
 366         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 367                                       GFP_USER);
 368         if (!page_virt) {
 369                 rc = -ENOMEM;
 370                 ecryptfs_printk(KERN_ERR,
 371                                 "Cannot ecryptfs_kmalloc a page\n");
 372                 goto out_dput;
 373         }
 374         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 375         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 376                 ecryptfs_set_default_sizes(crypt_stat);
 377         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
 378                                                       nd->mnt);
 379         if (rc) {
 380                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 381                 if (rc) {
 382                         printk(KERN_DEBUG "Valid metadata not found in header "
 383                                "region or xattr region; treating file as "
 384                                "unencrypted\n");
 385                         rc = 0;
 386                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 387                         goto out;
 388                 }
 389                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 390         }
 391         mount_crypt_stat = &ecryptfs_superblock_to_private(
 392                 dentry->d_sb)->mount_crypt_stat;
 393         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 394                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 395                         file_size = ((crypt_stat->extent_size
 396                                       * crypt_stat->num_header_extents_at_front)
 397                                      + i_size_read(lower_dentry->d_inode));
 398                 else
 399                         file_size = i_size_read(lower_dentry->d_inode);
 400         } else {
 401                 memcpy(&file_size, page_virt, sizeof(file_size));
 402                 file_size = be64_to_cpu(file_size);
 403         }
 404         i_size_write(dentry->d_inode, (loff_t)file_size);
 405         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 406         goto out;
 407
 408 out_dput:
 409         dput(lower_dentry);
 410         d_drop(dentry);
 411 out:
 412         return ERR_PTR(rc);
 413 }
 414
 415 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 416                          struct dentry *new_dentry)
 417 {
 418         struct dentry *lower_old_dentry;
 419         struct dentry *lower_new_dentry;
 420         struct dentry *lower_dir_dentry;
 421         u64 file_size_save;
 422         int rc;
 423
 424         file_size_save = i_size_read(old_dentry->d_inode);
 425         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 426         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 427         dget(lower_old_dentry);
 428         dget(lower_new_dentry);
 429         lower_dir_dentry = lock_parent(lower_new_dentry);
 430         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 431                       lower_new_dentry);
 432         if (rc || !lower_new_dentry->d_inode)
 433                 goto out_lock;
 434         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 435         if (rc)
 436                 goto out_lock;
 437         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 438         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 439         old_dentry->d_inode->i_nlink =
 440                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 441         i_size_write(new_dentry->d_inode, file_size_save);
 442 out_lock:
 443         unlock_dir(lower_dir_dentry);
 444         dput(lower_new_dentry);
 445         dput(lower_old_dentry);
 446         d_drop(lower_old_dentry);
 447         d_drop(new_dentry);
 448         d_drop(old_dentry);
 449         return rc;
 450 }
 451
 452 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 453 {
 454         int rc = 0;
 455         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 456         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 457
 458         lock_parent(lower_dentry);
 459         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 460         if (rc) {
 461                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 462                 goto out_unlock;
 463         }
 464         fsstack_copy_attr_times(dir, lower_dir_inode);
 465         dentry->d_inode->i_nlink =
 466                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 467         dentry->d_inode->i_ctime = dir->i_ctime;
 468 out_unlock:
 469         unlock_parent(lower_dentry);
 470         return rc;
 471 }
 472
 473 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 474                             const char *symname)
 475 {
 476         int rc;
 477         struct dentry *lower_dentry;
 478         struct dentry *lower_dir_dentry;
 479         umode_t mode;
 480         char *encoded_symname;
 481         int encoded_symlen;
 482         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 483
 484         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 485         dget(lower_dentry);
 486         lower_dir_dentry = lock_parent(lower_dentry);
 487         mode = S_IALLUGO;
 488         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 489                                                   strlen(symname),
 490                                                   &encoded_symname);
 491         if (encoded_symlen < 0) {
 492                 rc = encoded_symlen;
 493                 goto out_lock;
 494         }
 495         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 496                          encoded_symname, mode);
 497         kfree(encoded_symname);
 498         if (rc || !lower_dentry->d_inode)
 499                 goto out_lock;
 500         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 501         if (rc)
 502                 goto out_lock;
 503         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 504         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 505 out_lock:
 506         unlock_dir(lower_dir_dentry);
 507         dput(lower_dentry);
 508         if (!dentry->d_inode)
 509                 d_drop(dentry);
 510         return rc;
 511 }
 512
 513 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 514 {
 515         int rc;
 516         struct dentry *lower_dentry;
 517         struct dentry *lower_dir_dentry;
 518
 519         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 520         lower_dir_dentry = lock_parent(lower_dentry);
 521         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 522         if (rc || !lower_dentry->d_inode)
 523                 goto out;
 524         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 525         if (rc)
 526                 goto out;
 527         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 528         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 529         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 530 out:
 531         unlock_dir(lower_dir_dentry);
 532         if (!dentry->d_inode)
 533                 d_drop(dentry);
 534         return rc;
 535 }
 536
 537 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 538 {
 539         struct dentry *lower_dentry;
 540         struct dentry *lower_dir_dentry;
 541         int rc;
 542
 543         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 544         dget(dentry);
 545         lower_dir_dentry = lock_parent(lower_dentry);
 546         dget(lower_dentry);
 547         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 548         dput(lower_dentry);
 549         if (!rc)
 550                 d_delete(lower_dentry);
 551         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 552         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 553         unlock_dir(lower_dir_dentry);
 554         if (!rc)
 555                 d_drop(dentry);
 556         dput(dentry);
 557         return rc;
 558 }
 559
 560 static int
 561 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 562 {
 563         int rc;
 564         struct dentry *lower_dentry;
 565         struct dentry *lower_dir_dentry;
 566
 567         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 568         lower_dir_dentry = lock_parent(lower_dentry);
 569         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 570         if (rc || !lower_dentry->d_inode)
 571                 goto out;
 572         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 573         if (rc)
 574                 goto out;
 575         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 576         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 577 out:
 578         unlock_dir(lower_dir_dentry);
 579         if (!dentry->d_inode)
 580                 d_drop(dentry);
 581         return rc;
 582 }
 583
 584 static int
 585 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 586                 struct inode *new_dir, struct dentry *new_dentry)
 587 {
 588         int rc;
 589         struct dentry *lower_old_dentry;
 590         struct dentry *lower_new_dentry;
 591         struct dentry *lower_old_dir_dentry;
 592         struct dentry *lower_new_dir_dentry;
 593
 594         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 595         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 596         dget(lower_old_dentry);
 597         dget(lower_new_dentry);
 598         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 599         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 600         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 601         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 602                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 603         if (rc)
 604                 goto out_lock;
 605         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 606         if (new_dir != old_dir)
 607                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 608 out_lock:
 609         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 610         dput(lower_new_dentry->d_parent);
 611         dput(lower_old_dentry->d_parent);
 612         dput(lower_new_dentry);
 613         dput(lower_old_dentry);
 614         return rc;
 615 }
 616
 617 static int
 618 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 619 {
 620         int rc;
 621         struct dentry *lower_dentry;
 622         char *decoded_name;
 623         char *lower_buf;
 624         mm_segment_t old_fs;
 625         struct ecryptfs_crypt_stat *crypt_stat;
 626
 627         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 628         if (!lower_dentry->d_inode->i_op ||
 629             !lower_dentry->d_inode->i_op->readlink) {
 630                 rc = -EINVAL;
 631                 goto out;
 632         }
 633         /* Released in this function */
 634         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 635         if (lower_buf == NULL) {
 636                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 637                 rc = -ENOMEM;
 638                 goto out;
 639         }
 640         old_fs = get_fs();
 641         set_fs(get_ds());
 642         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 643                         "lower_dentry->d_name.name = [%s]\n",
 644                         lower_dentry->d_name.name);
 645         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 646                                                    (char __user *)lower_buf,
 647                                                    bufsiz);
 648         set_fs(old_fs);
 649         if (rc >= 0) {
 650                 crypt_stat = NULL;
 651                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 652                                               &decoded_name);
 653                 if (rc == -ENOMEM)
 654                         goto out_free_lower_buf;
 655                 if (rc > 0) {
 656                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 657                                         "to userspace: [%*s]\n", rc,
 658                                         decoded_name);
 659                         if (copy_to_user(buf, decoded_name, rc))
 660                                 rc = -EFAULT;
 661                 }
 662                 kfree(decoded_name);
 663                 fsstack_copy_attr_atime(dentry->d_inode,
 664                                         lower_dentry->d_inode);
 665         }
 666 out_free_lower_buf:
 667         kfree(lower_buf);
 668 out:
 669         return rc;
 670 }
 671
 672 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 673 {
 674         char *buf;
 675         int len = PAGE_SIZE, rc;
 676         mm_segment_t old_fs;
 677
 678         /* Released in ecryptfs_put_link(); only release here on error */
 679         buf = kmalloc(len, GFP_KERNEL);
 680         if (!buf) {
 681                 rc = -ENOMEM;
 682                 goto out;
 683         }
 684         old_fs = get_fs();
 685         set_fs(get_ds());
 686         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 687                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 688         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 689         buf[rc] = '\0';
 690         set_fs(old_fs);
 691         if (rc < 0)
 692                 goto out_free;
 693         rc = 0;
 694         nd_set_link(nd, buf);
 695         goto out;
 696 out_free:
 697         kfree(buf);
 698 out:
 699         return ERR_PTR(rc);
 700 }
 701
 702 static void
 703 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 704 {
 705         /* Free the char* */
 706         kfree(nd_get_link(nd));
 707 }
 708
 709 /**
 710  * upper_size_to_lower_size
 711  * @crypt_stat: Crypt_stat associated with file
 712  * @upper_size: Size of the upper file
 713  *
 714  * Calculate the requried size of the lower file based on the
 715  * specified size of the upper file. This calculation is based on the
 716  * number of headers in the underlying file and the extent size.
 717  *
 718  * Returns Calculated size of the lower file.
 719  */
 720 static loff_t
 721 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 722                          loff_t upper_size)
 723 {
 724         loff_t lower_size;
 725
 726         lower_size = (crypt_stat->extent_size
 727                       * crypt_stat->num_header_extents_at_front);
 728         if (upper_size != 0) {
 729                 loff_t num_extents;
 730
 731                 num_extents = upper_size >> crypt_stat->extent_shift;
 732                 if (upper_size & ~crypt_stat->extent_mask)
 733                         num_extents++;
 734                 lower_size += (num_extents * crypt_stat->extent_size);
 735         }
 736         return lower_size;
 737 }
 738
 739 /**
 740  * ecryptfs_truncate
 741  * @dentry: The ecryptfs layer dentry
 742  * @new_length: The length to expand the file to
 743  *
 744  * Function to handle truncations modifying the size of the file. Note
 745  * that the file sizes are interpolated. When expanding, we are simply
 746  * writing strings of 0's out. When truncating, we need to modify the
 747  * underlying file size according to the page index interpolations.
 748  *
 749  * Returns zero on success; non-zero otherwise
 750  */
 751 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 752 {
 753         int rc = 0;
 754         struct inode *inode = dentry->d_inode;
 755         struct dentry *lower_dentry;
 756         struct vfsmount *lower_mnt;
 757         struct file fake_ecryptfs_file, *lower_file = NULL;
 758         struct ecryptfs_crypt_stat *crypt_stat;
 759         loff_t i_size = i_size_read(inode);
 760         loff_t lower_size_before_truncate;
 761         loff_t lower_size_after_truncate;
 762
 763         if (unlikely((new_length == i_size)))
 764                 goto out;
 765         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 766         /* Set up a fake ecryptfs file, this is used to interface with
 767          * the file in the underlying filesystem so that the
 768          * truncation has an effect there as well. */
 769         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 770         fake_ecryptfs_file.f_path.dentry = dentry;
 771         /* Released at out_free: label */
 772         ecryptfs_set_file_private(&fake_ecryptfs_file,
 773                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 774                                                    GFP_KERNEL));
 775         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 776                 rc = -ENOMEM;
 777                 goto out;
 778         }
 779         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 780         /* This dget & mntget is released through fput at out_fput: */
 781         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 782         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 783                                            O_RDWR))) {
 784                 ecryptfs_printk(KERN_ERR,
 785                                 "Error opening dentry; rc = [%i]\n", rc);
 786                 goto out_free;
 787         }
 788         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 789         /* Switch on growing or shrinking file */
 790         if (new_length > i_size) {
 791                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 792                 if (rc) {
 793                         ecryptfs_printk(KERN_ERR,
 794                                         "Problem with fill_zeros\n");
 795                         goto out_fput;
 796                 }
 797                 i_size_write(inode, new_length);
 798                 rc = ecryptfs_write_inode_size_to_metadata(
 799                         lower_file, lower_dentry->d_inode, inode, dentry,
 800                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 801                 if (rc) {
 802                         printk(KERN_ERR "Problem with "
 803                                "ecryptfs_write_inode_size_to_metadata; "
 804                                "rc = [%d]\n", rc);
 805                         goto out_fput;
 806                 }
 807         } else { /* new_length < i_size_read(inode) */
 808                 pgoff_t index = 0;
 809                 int end_pos_in_page = -1;
 810
 811                 if (new_length != 0) {
 812                         index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
 813                         end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
 814                 }
 815                 if (end_pos_in_page != (PAGE_CACHE_SIZE - 1)) {
 816                         if ((rc = ecryptfs_write_zeros(&fake_ecryptfs_file,
 817                                                        index,
 818                                                        (end_pos_in_page + 1),
 819                                                        ((PAGE_CACHE_SIZE - 1)
 820                                                         - end_pos_in_page)))) {
 821                                 printk(KERN_ERR "Error attempting to zero out "
 822                                        "the remainder of the end page on "
 823                                        "reducing truncate; rc = [%d]\n", rc);
 824                                 goto out_fput;
 825                         }
 826                 }
 827                 vmtruncate(inode, new_length);
 828                 rc = ecryptfs_write_inode_size_to_metadata(
 829                         lower_file, lower_dentry->d_inode, inode, dentry,
 830                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 831                 if (rc) {
 832                         printk(KERN_ERR "Problem with "
 833                                "ecryptfs_write_inode_size_to_metadata; "
 834                                "rc = [%d]\n", rc);
 835                         goto out_fput;
 836                 }
 837                 /* We are reducing the size of the ecryptfs file, and need to
 838                  * know if we need to reduce the size of the lower file. */
 839                 lower_size_before_truncate =
 840                     upper_size_to_lower_size(crypt_stat, i_size);
 841                 lower_size_after_truncate =
 842                     upper_size_to_lower_size(crypt_stat, new_length);
 843                 if (lower_size_after_truncate < lower_size_before_truncate)
 844                         vmtruncate(lower_dentry->d_inode,
 845                                    lower_size_after_truncate);
 846         }
 847         /* Update the access times */
 848         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 849                 = CURRENT_TIME;
 850         mark_inode_dirty_sync(inode);
 851 out_fput:
 852         if ((rc = ecryptfs_close_lower_file(lower_file)))
 853                 printk(KERN_ERR "Error closing lower_file\n");
 854 out_free:
 855         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 856                 kmem_cache_free(ecryptfs_file_info_cache,
 857                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 858 out:
 859         return rc;
 860 }
 861
 862 static int
 863 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 864 {
 865         int rc;
 866
 867         if (nd) {
 868                 struct vfsmount *vfsmnt_save = nd->mnt;
 869                 struct dentry *dentry_save = nd->dentry;
 870
 871                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 872                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 873                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 874                 nd->mnt = vfsmnt_save;
 875                 nd->dentry = dentry_save;
 876         } else
 877                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 878         return rc;
 879 }
 880
 881 /**
 882  * ecryptfs_setattr
 883  * @dentry: dentry handle to the inode to modify
 884  * @ia: Structure with flags of what to change and values
 885  *
 886  * Updates the metadata of an inode. If the update is to the size
 887  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 888  * of both the ecryptfs inode and the lower inode.
 889  *
 890  * All other metadata changes will be passed right to the lower filesystem,
 891  * and we will just update our inode to look like the lower.
 892  */
 893 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 894 {
 895         int rc = 0;
 896         struct dentry *lower_dentry;
 897         struct inode *inode;
 898         struct inode *lower_inode;
 899         struct ecryptfs_crypt_stat *crypt_stat;
 900
 901         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 902         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 903                 ecryptfs_init_crypt_stat(crypt_stat);
 904         inode = dentry->d_inode;
 905         lower_inode = ecryptfs_inode_to_lower(inode);
 906         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 907         mutex_lock(&crypt_stat->cs_mutex);
 908         if (S_ISDIR(dentry->d_inode->i_mode))
 909                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 910         else if (S_ISREG(dentry->d_inode->i_mode)
 911                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 912                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 913                 struct vfsmount *lower_mnt;
 914                 struct file *lower_file = NULL;
 915                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 916                 int lower_flags;
 917
 918                 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 919                 lower_flags = O_RDONLY;
 920                 if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
 921                                                    lower_mnt, lower_flags))) {
 922                         printk(KERN_ERR
 923                                "Error opening lower file; rc = [%d]\n", rc);
 924                         mutex_unlock(&crypt_stat->cs_mutex);
 925                         goto out;
 926                 }
 927                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 928                         dentry->d_sb)->mount_crypt_stat;
 929                 if ((rc = ecryptfs_read_metadata(dentry, lower_file))) {
 930                         if (!(mount_crypt_stat->flags
 931                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 932                                 rc = -EIO;
 933                                 printk(KERN_WARNING "Attempt to read file that "
 934                                        "is not in a valid eCryptfs format, "
 935                                        "and plaintext passthrough mode is not "
 936                                        "enabled; returning -EIO\n");
 937
 938                                 mutex_unlock(&crypt_stat->cs_mutex);
 939                                 fput(lower_file);
 940                                 goto out;
 941                         }
 942                         rc = 0;
 943                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 944                         mutex_unlock(&crypt_stat->cs_mutex);
 945                         fput(lower_file);
 946                         goto out;
 947                 }
 948                 fput(lower_file);
 949         }
 950         mutex_unlock(&crypt_stat->cs_mutex);
 951         if (ia->ia_valid & ATTR_SIZE) {
 952                 ecryptfs_printk(KERN_DEBUG,
 953                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 954                                 ia->ia_valid, ATTR_SIZE);
 955                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 956                 /* ecryptfs_truncate handles resizing of the lower file */
 957                 ia->ia_valid &= ~ATTR_SIZE;
 958                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 959                                 ia->ia_valid);
 960                 if (rc < 0)
 961                         goto out;
 962         }
 963         rc = notify_change(lower_dentry, ia);
 964 out:
 965         fsstack_copy_attr_all(inode, lower_inode, NULL);
 966         return rc;
 967 }
 968
 969 int
 970 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 971                   size_t size, int flags)
 972 {
 973         int rc = 0;
 974         struct dentry *lower_dentry;
 975
 976         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 977         if (!lower_dentry->d_inode->i_op->setxattr) {
 978                 rc = -ENOSYS;
 979                 goto out;
 980         }
 981         mutex_lock(&lower_dentry->d_inode->i_mutex);
 982         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 983                                                    size, flags);
 984         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 985 out:
 986         return rc;
 987 }
 988
 989 ssize_t
 990 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 991                   size_t size)
 992 {
 993         int rc = 0;
 994         struct dentry *lower_dentry;
 995
 996         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 997         if (!lower_dentry->d_inode->i_op->getxattr) {
 998                 rc = -ENOSYS;
 999                 goto out;
1000         }
1001         mutex_lock(&lower_dentry->d_inode->i_mutex);
1002         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1003                                                    size);
1004         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1005 out:
1006         return rc;
1007 }
1008
1009 static ssize_t
1010 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1011 {
1012         int rc = 0;
1013         struct dentry *lower_dentry;
1014
1015         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1016         if (!lower_dentry->d_inode->i_op->listxattr) {
1017                 rc = -ENOSYS;
1018                 goto out;
1019         }
1020         mutex_lock(&lower_dentry->d_inode->i_mutex);
1021         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1022         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1023 out:
1024         return rc;
1025 }
1026
1027 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1028 {
1029         int rc = 0;
1030         struct dentry *lower_dentry;
1031
1032         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1033         if (!lower_dentry->d_inode->i_op->removexattr) {
1034                 rc = -ENOSYS;
1035                 goto out;
1036         }
1037         mutex_lock(&lower_dentry->d_inode->i_mutex);
1038         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1039         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1040 out:
1041         return rc;
1042 }
1043
1044 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1045 {
1046         if ((ecryptfs_inode_to_lower(inode)
1047              == (struct inode *)candidate_lower_inode))
1048                 return 1;
1049         else
1050                 return 0;
1051 }
1052
1053 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1054 {
1055         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1056         return 0;
1057 }
1058
1059 const struct inode_operations ecryptfs_symlink_iops = {
1060         .readlink = ecryptfs_readlink,
1061         .follow_link = ecryptfs_follow_link,
1062         .put_link = ecryptfs_put_link,
1063         .permission = ecryptfs_permission,
1064         .setattr = ecryptfs_setattr,
1065         .setxattr = ecryptfs_setxattr,
1066         .getxattr = ecryptfs_getxattr,
1067         .listxattr = ecryptfs_listxattr,
1068         .removexattr = ecryptfs_removexattr
1069 };
1070
1071 const struct inode_operations ecryptfs_dir_iops = {
1072         .create = ecryptfs_create,
1073         .lookup = ecryptfs_lookup,
1074         .link = ecryptfs_link,
1075         .unlink = ecryptfs_unlink,
1076         .symlink = ecryptfs_symlink,
1077         .mkdir = ecryptfs_mkdir,
1078         .rmdir = ecryptfs_rmdir,
1079         .mknod = ecryptfs_mknod,
1080         .rename = ecryptfs_rename,
1081         .permission = ecryptfs_permission,
1082         .setattr = ecryptfs_setattr,
1083         .setxattr = ecryptfs_setxattr,
1084         .getxattr = ecryptfs_getxattr,
1085         .listxattr = ecryptfs_listxattr,
1086         .removexattr = ecryptfs_removexattr
1087 };
1088
1089 const struct inode_operations ecryptfs_main_iops = {
1090         .permission = ecryptfs_permission,
1091         .setattr = ecryptfs_setattr,
1092         .setxattr = ecryptfs_setxattr,
1093         .getxattr = ecryptfs_getxattr,
1094         .listxattr = ecryptfs_listxattr,
1095         .removexattr = ecryptfs_removexattr
1096 };