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 (special_file(lower_inode->i_mode)) {
 361                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
 362                 goto out;
 363         }
 364         if (!nd) {
 365                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 366                                 "as we *think* we are about to unlink\n");
 367                 goto out;
 368         }
 369         /* Released in this function */
 370         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 371                                       GFP_USER);
 372         if (!page_virt) {
 373                 rc = -ENOMEM;
 374                 ecryptfs_printk(KERN_ERR,
 375                                 "Cannot ecryptfs_kmalloc a page\n");
 376                 goto out_dput;
 377         }
 378         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 379         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 380                 ecryptfs_set_default_sizes(crypt_stat);
 381         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
 382                                                       nd->mnt);
 383         if (rc) {
 384                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 385                 if (rc) {
 386                         printk(KERN_DEBUG "Valid metadata not found in header "
 387                                "region or xattr region; treating file as "
 388                                "unencrypted\n");
 389                         rc = 0;
 390                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 391                         goto out;
 392                 }
 393                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 394         }
 395         mount_crypt_stat = &ecryptfs_superblock_to_private(
 396                 dentry->d_sb)->mount_crypt_stat;
 397         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 398                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 399                         file_size = (crypt_stat->header_extent_size
 400                                      + i_size_read(lower_dentry->d_inode));
 401                 else
 402                         file_size = i_size_read(lower_dentry->d_inode);
 403         } else {
 404                 memcpy(&file_size, page_virt, sizeof(file_size));
 405                 file_size = be64_to_cpu(file_size);
 406         }
 407         i_size_write(dentry->d_inode, (loff_t)file_size);
 408         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 409         goto out;
 410
 411 out_dput:
 412         dput(lower_dentry);
 413         d_drop(dentry);
 414 out:
 415         return ERR_PTR(rc);
 416 }
 417
 418 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 419                          struct dentry *new_dentry)
 420 {
 421         struct dentry *lower_old_dentry;
 422         struct dentry *lower_new_dentry;
 423         struct dentry *lower_dir_dentry;
 424         u64 file_size_save;
 425         int rc;
 426
 427         file_size_save = i_size_read(old_dentry->d_inode);
 428         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 429         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 430         dget(lower_old_dentry);
 431         dget(lower_new_dentry);
 432         lower_dir_dentry = lock_parent(lower_new_dentry);
 433         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 434                       lower_new_dentry);
 435         if (rc || !lower_new_dentry->d_inode)
 436                 goto out_lock;
 437         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 438         if (rc)
 439                 goto out_lock;
 440         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 441         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 442         old_dentry->d_inode->i_nlink =
 443                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 444         i_size_write(new_dentry->d_inode, file_size_save);
 445 out_lock:
 446         unlock_dir(lower_dir_dentry);
 447         dput(lower_new_dentry);
 448         dput(lower_old_dentry);
 449         d_drop(lower_old_dentry);
 450         d_drop(new_dentry);
 451         d_drop(old_dentry);
 452         return rc;
 453 }
 454
 455 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 456 {
 457         int rc = 0;
 458         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 459         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 460
 461         lock_parent(lower_dentry);
 462         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 463         if (rc) {
 464                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 465                 goto out_unlock;
 466         }
 467         fsstack_copy_attr_times(dir, lower_dir_inode);
 468         dentry->d_inode->i_nlink =
 469                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 470         dentry->d_inode->i_ctime = dir->i_ctime;
 471 out_unlock:
 472         unlock_parent(lower_dentry);
 473         return rc;
 474 }
 475
 476 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 477                             const char *symname)
 478 {
 479         int rc;
 480         struct dentry *lower_dentry;
 481         struct dentry *lower_dir_dentry;
 482         umode_t mode;
 483         char *encoded_symname;
 484         int encoded_symlen;
 485         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 486
 487         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 488         dget(lower_dentry);
 489         lower_dir_dentry = lock_parent(lower_dentry);
 490         mode = S_IALLUGO;
 491         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 492                                                   strlen(symname),
 493                                                   &encoded_symname);
 494         if (encoded_symlen < 0) {
 495                 rc = encoded_symlen;
 496                 goto out_lock;
 497         }
 498         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 499                          encoded_symname, mode);
 500         kfree(encoded_symname);
 501         if (rc || !lower_dentry->d_inode)
 502                 goto out_lock;
 503         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 504         if (rc)
 505                 goto out_lock;
 506         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 507         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 508 out_lock:
 509         unlock_dir(lower_dir_dentry);
 510         dput(lower_dentry);
 511         if (!dentry->d_inode)
 512                 d_drop(dentry);
 513         return rc;
 514 }
 515
 516 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 517 {
 518         int rc;
 519         struct dentry *lower_dentry;
 520         struct dentry *lower_dir_dentry;
 521
 522         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 523         lower_dir_dentry = lock_parent(lower_dentry);
 524         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 525         if (rc || !lower_dentry->d_inode)
 526                 goto out;
 527         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 528         if (rc)
 529                 goto out;
 530         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 531         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 532         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 533 out:
 534         unlock_dir(lower_dir_dentry);
 535         if (!dentry->d_inode)
 536                 d_drop(dentry);
 537         return rc;
 538 }
 539
 540 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 541 {
 542         struct dentry *lower_dentry;
 543         struct dentry *lower_dir_dentry;
 544         int rc;
 545
 546         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 547         dget(dentry);
 548         lower_dir_dentry = lock_parent(lower_dentry);
 549         dget(lower_dentry);
 550         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 551         dput(lower_dentry);
 552         if (!rc)
 553                 d_delete(lower_dentry);
 554         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 555         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 556         unlock_dir(lower_dir_dentry);
 557         if (!rc)
 558                 d_drop(dentry);
 559         dput(dentry);
 560         return rc;
 561 }
 562
 563 static int
 564 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 565 {
 566         int rc;
 567         struct dentry *lower_dentry;
 568         struct dentry *lower_dir_dentry;
 569
 570         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 571         lower_dir_dentry = lock_parent(lower_dentry);
 572         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 573         if (rc || !lower_dentry->d_inode)
 574                 goto out;
 575         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 576         if (rc)
 577                 goto out;
 578         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 579         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 580 out:
 581         unlock_dir(lower_dir_dentry);
 582         if (!dentry->d_inode)
 583                 d_drop(dentry);
 584         return rc;
 585 }
 586
 587 static int
 588 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 589                 struct inode *new_dir, struct dentry *new_dentry)
 590 {
 591         int rc;
 592         struct dentry *lower_old_dentry;
 593         struct dentry *lower_new_dentry;
 594         struct dentry *lower_old_dir_dentry;
 595         struct dentry *lower_new_dir_dentry;
 596
 597         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 598         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 599         dget(lower_old_dentry);
 600         dget(lower_new_dentry);
 601         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 602         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 603         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 604         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 605                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 606         if (rc)
 607                 goto out_lock;
 608         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 609         if (new_dir != old_dir)
 610                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 611 out_lock:
 612         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 613         dput(lower_new_dentry->d_parent);
 614         dput(lower_old_dentry->d_parent);
 615         dput(lower_new_dentry);
 616         dput(lower_old_dentry);
 617         return rc;
 618 }
 619
 620 static int
 621 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 622 {
 623         int rc;
 624         struct dentry *lower_dentry;
 625         char *decoded_name;
 626         char *lower_buf;
 627         mm_segment_t old_fs;
 628         struct ecryptfs_crypt_stat *crypt_stat;
 629
 630         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 631         if (!lower_dentry->d_inode->i_op ||
 632             !lower_dentry->d_inode->i_op->readlink) {
 633                 rc = -EINVAL;
 634                 goto out;
 635         }
 636         /* Released in this function */
 637         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 638         if (lower_buf == NULL) {
 639                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 640                 rc = -ENOMEM;
 641                 goto out;
 642         }
 643         old_fs = get_fs();
 644         set_fs(get_ds());
 645         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 646                         "lower_dentry->d_name.name = [%s]\n",
 647                         lower_dentry->d_name.name);
 648         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 649                                                    (char __user *)lower_buf,
 650                                                    bufsiz);
 651         set_fs(old_fs);
 652         if (rc >= 0) {
 653                 crypt_stat = NULL;
 654                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 655                                               &decoded_name);
 656                 if (rc == -ENOMEM)
 657                         goto out_free_lower_buf;
 658                 if (rc > 0) {
 659                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 660                                         "to userspace: [%*s]\n", rc,
 661                                         decoded_name);
 662                         if (copy_to_user(buf, decoded_name, rc))
 663                                 rc = -EFAULT;
 664                 }
 665                 kfree(decoded_name);
 666                 fsstack_copy_attr_atime(dentry->d_inode,
 667                                         lower_dentry->d_inode);
 668         }
 669 out_free_lower_buf:
 670         kfree(lower_buf);
 671 out:
 672         return rc;
 673 }
 674
 675 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 676 {
 677         char *buf;
 678         int len = PAGE_SIZE, rc;
 679         mm_segment_t old_fs;
 680
 681         /* Released in ecryptfs_put_link(); only release here on error */
 682         buf = kmalloc(len, GFP_KERNEL);
 683         if (!buf) {
 684                 rc = -ENOMEM;
 685                 goto out;
 686         }
 687         old_fs = get_fs();
 688         set_fs(get_ds());
 689         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 690                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 691         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 692         buf[rc] = '\0';
 693         set_fs(old_fs);
 694         if (rc < 0)
 695                 goto out_free;
 696         rc = 0;
 697         nd_set_link(nd, buf);
 698         goto out;
 699 out_free:
 700         kfree(buf);
 701 out:
 702         return ERR_PTR(rc);
 703 }
 704
 705 static void
 706 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 707 {
 708         /* Free the char* */
 709         kfree(nd_get_link(nd));
 710 }
 711
 712 /**
 713  * upper_size_to_lower_size
 714  * @crypt_stat: Crypt_stat associated with file
 715  * @upper_size: Size of the upper file
 716  *
 717  * Calculate the requried size of the lower file based on the
 718  * specified size of the upper file. This calculation is based on the
 719  * number of headers in the underlying file and the extent size.
 720  *
 721  * Returns Calculated size of the lower file.
 722  */
 723 static loff_t
 724 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 725                          loff_t upper_size)
 726 {
 727         loff_t lower_size;
 728
 729         lower_size = ( crypt_stat->header_extent_size
 730                        * crypt_stat->num_header_extents_at_front );
 731         if (upper_size != 0) {
 732                 loff_t num_extents;
 733
 734                 num_extents = upper_size >> crypt_stat->extent_shift;
 735                 if (upper_size & ~crypt_stat->extent_mask)
 736                         num_extents++;
 737                 lower_size += (num_extents * crypt_stat->extent_size);
 738         }
 739         return lower_size;
 740 }
 741
 742 /**
 743  * ecryptfs_truncate
 744  * @dentry: The ecryptfs layer dentry
 745  * @new_length: The length to expand the file to
 746  *
 747  * Function to handle truncations modifying the size of the file. Note
 748  * that the file sizes are interpolated. When expanding, we are simply
 749  * writing strings of 0's out. When truncating, we need to modify the
 750  * underlying file size according to the page index interpolations.
 751  *
 752  * Returns zero on success; non-zero otherwise
 753  */
 754 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 755 {
 756         int rc = 0;
 757         struct inode *inode = dentry->d_inode;
 758         struct dentry *lower_dentry;
 759         struct vfsmount *lower_mnt;
 760         struct file fake_ecryptfs_file, *lower_file = NULL;
 761         struct ecryptfs_crypt_stat *crypt_stat;
 762         loff_t i_size = i_size_read(inode);
 763         loff_t lower_size_before_truncate;
 764         loff_t lower_size_after_truncate;
 765
 766         if (unlikely((new_length == i_size)))
 767                 goto out;
 768         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 769         /* Set up a fake ecryptfs file, this is used to interface with
 770          * the file in the underlying filesystem so that the
 771          * truncation has an effect there as well. */
 772         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 773         fake_ecryptfs_file.f_path.dentry = dentry;
 774         /* Released at out_free: label */
 775         ecryptfs_set_file_private(&fake_ecryptfs_file,
 776                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 777                                                    GFP_KERNEL));
 778         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 779                 rc = -ENOMEM;
 780                 goto out;
 781         }
 782         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 783         /* This dget & mntget is released through fput at out_fput: */
 784         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 785         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 786                                            O_RDWR))) {
 787                 ecryptfs_printk(KERN_ERR,
 788                                 "Error opening dentry; rc = [%i]\n", rc);
 789                 goto out_free;
 790         }
 791         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 792         /* Switch on growing or shrinking file */
 793         if (new_length > i_size) {
 794                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 795                 if (rc) {
 796                         ecryptfs_printk(KERN_ERR,
 797                                         "Problem with fill_zeros\n");
 798                         goto out_fput;
 799                 }
 800                 i_size_write(inode, new_length);
 801                 rc = ecryptfs_write_inode_size_to_metadata(
 802                         lower_file, lower_dentry->d_inode, inode, dentry,
 803                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 804                 if (rc) {
 805                         printk(KERN_ERR "Problem with "
 806                                "ecryptfs_write_inode_size_to_metadata; "
 807                                "rc = [%d]\n", rc);
 808                         goto out_fput;
 809                 }
 810         } else { /* new_length < i_size_read(inode) */
 811                 pgoff_t index = 0;
 812                 int end_pos_in_page = -1;
 813
 814                 if (new_length != 0) {
 815                         index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
 816                         end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
 817                 }
 818                 if (end_pos_in_page != (PAGE_CACHE_SIZE - 1)) {
 819                         if ((rc = ecryptfs_write_zeros(&fake_ecryptfs_file,
 820                                                        index,
 821                                                        (end_pos_in_page + 1),
 822                                                        ((PAGE_CACHE_SIZE - 1)
 823                                                         - end_pos_in_page)))) {
 824                                 printk(KERN_ERR "Error attempting to zero out "
 825                                        "the remainder of the end page on "
 826                                        "reducing truncate; rc = [%d]\n", rc);
 827                                 goto out_fput;
 828                         }
 829                 }
 830                 vmtruncate(inode, new_length);
 831                 rc = ecryptfs_write_inode_size_to_metadata(
 832                         lower_file, lower_dentry->d_inode, inode, dentry,
 833                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 834                 if (rc) {
 835                         printk(KERN_ERR "Problem with "
 836                                "ecryptfs_write_inode_size_to_metadata; "
 837                                "rc = [%d]\n", rc);
 838                         goto out_fput;
 839                 }
 840                 /* We are reducing the size of the ecryptfs file, and need to
 841                  * know if we need to reduce the size of the lower file. */
 842                 lower_size_before_truncate =
 843                     upper_size_to_lower_size(crypt_stat, i_size);
 844                 lower_size_after_truncate =
 845                     upper_size_to_lower_size(crypt_stat, new_length);
 846                 if (lower_size_after_truncate < lower_size_before_truncate)
 847                         vmtruncate(lower_dentry->d_inode,
 848                                    lower_size_after_truncate);
 849         }
 850         /* Update the access times */
 851         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 852                 = CURRENT_TIME;
 853         mark_inode_dirty_sync(inode);
 854 out_fput:
 855         if ((rc = ecryptfs_close_lower_file(lower_file)))
 856                 printk(KERN_ERR "Error closing lower_file\n");
 857 out_free:
 858         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 859                 kmem_cache_free(ecryptfs_file_info_cache,
 860                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 861 out:
 862         return rc;
 863 }
 864
 865 static int
 866 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 867 {
 868         int rc;
 869
 870         if (nd) {
 871                 struct vfsmount *vfsmnt_save = nd->mnt;
 872                 struct dentry *dentry_save = nd->dentry;
 873
 874                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 875                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 876                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 877                 nd->mnt = vfsmnt_save;
 878                 nd->dentry = dentry_save;
 879         } else
 880                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 881         return rc;
 882 }
 883
 884 /**
 885  * ecryptfs_setattr
 886  * @dentry: dentry handle to the inode to modify
 887  * @ia: Structure with flags of what to change and values
 888  *
 889  * Updates the metadata of an inode. If the update is to the size
 890  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 891  * of both the ecryptfs inode and the lower inode.
 892  *
 893  * All other metadata changes will be passed right to the lower filesystem,
 894  * and we will just update our inode to look like the lower.
 895  */
 896 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 897 {
 898         int rc = 0;
 899         struct dentry *lower_dentry;
 900         struct inode *inode;
 901         struct inode *lower_inode;
 902         struct ecryptfs_crypt_stat *crypt_stat;
 903
 904         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 905         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 906                 ecryptfs_init_crypt_stat(crypt_stat);
 907         inode = dentry->d_inode;
 908         lower_inode = ecryptfs_inode_to_lower(inode);
 909         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 910         mutex_lock(&crypt_stat->cs_mutex);
 911         if (S_ISDIR(dentry->d_inode->i_mode))
 912                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 913         else if (S_ISREG(dentry->d_inode->i_mode)
 914                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 915                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 916                 struct vfsmount *lower_mnt;
 917                 struct file *lower_file = NULL;
 918                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 919                 int lower_flags;
 920
 921                 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 922                 lower_flags = O_RDONLY;
 923                 if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
 924                                                    lower_mnt, lower_flags))) {
 925                         printk(KERN_ERR
 926                                "Error opening lower file; rc = [%d]\n", rc);
 927                         mutex_unlock(&crypt_stat->cs_mutex);
 928                         goto out;
 929                 }
 930                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 931                         dentry->d_sb)->mount_crypt_stat;
 932                 if ((rc = ecryptfs_read_metadata(dentry, lower_file))) {
 933                         if (!(mount_crypt_stat->flags
 934                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 935                                 rc = -EIO;
 936                                 printk(KERN_WARNING "Attempt to read file that "
 937                                        "is not in a valid eCryptfs format, "
 938                                        "and plaintext passthrough mode is not "
 939                                        "enabled; returning -EIO\n");
 940
 941                                 mutex_unlock(&crypt_stat->cs_mutex);
 942                                 fput(lower_file);
 943                                 goto out;
 944                         }
 945                         rc = 0;
 946                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 947                         mutex_unlock(&crypt_stat->cs_mutex);
 948                         fput(lower_file);
 949                         goto out;
 950                 }
 951                 fput(lower_file);
 952         }
 953         mutex_unlock(&crypt_stat->cs_mutex);
 954         if (ia->ia_valid & ATTR_SIZE) {
 955                 ecryptfs_printk(KERN_DEBUG,
 956                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 957                                 ia->ia_valid, ATTR_SIZE);
 958                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 959                 /* ecryptfs_truncate handles resizing of the lower file */
 960                 ia->ia_valid &= ~ATTR_SIZE;
 961                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 962                                 ia->ia_valid);
 963                 if (rc < 0)
 964                         goto out;
 965         }
 966         rc = notify_change(lower_dentry, ia);
 967 out:
 968         fsstack_copy_attr_all(inode, lower_inode, NULL);
 969         return rc;
 970 }
 971
 972 int
 973 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 974                   size_t size, int flags)
 975 {
 976         int rc = 0;
 977         struct dentry *lower_dentry;
 978
 979         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 980         if (!lower_dentry->d_inode->i_op->setxattr) {
 981                 rc = -ENOSYS;
 982                 goto out;
 983         }
 984         mutex_lock(&lower_dentry->d_inode->i_mutex);
 985         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 986                                                    size, flags);
 987         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 988 out:
 989         return rc;
 990 }
 991
 992 ssize_t
 993 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 994                   size_t size)
 995 {
 996         int rc = 0;
 997         struct dentry *lower_dentry;
 998
 999         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1000         if (!lower_dentry->d_inode->i_op->getxattr) {
1001                 rc = -ENOSYS;
1002                 goto out;
1003         }
1004         mutex_lock(&lower_dentry->d_inode->i_mutex);
1005         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1006                                                    size);
1007         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1008 out:
1009         return rc;
1010 }
1011
1012 static ssize_t
1013 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1014 {
1015         int rc = 0;
1016         struct dentry *lower_dentry;
1017
1018         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1019         if (!lower_dentry->d_inode->i_op->listxattr) {
1020                 rc = -ENOSYS;
1021                 goto out;
1022         }
1023         mutex_lock(&lower_dentry->d_inode->i_mutex);
1024         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1025         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1026 out:
1027         return rc;
1028 }
1029
1030 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1031 {
1032         int rc = 0;
1033         struct dentry *lower_dentry;
1034
1035         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1036         if (!lower_dentry->d_inode->i_op->removexattr) {
1037                 rc = -ENOSYS;
1038                 goto out;
1039         }
1040         mutex_lock(&lower_dentry->d_inode->i_mutex);
1041         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1042         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1043 out:
1044         return rc;
1045 }
1046
1047 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1048 {
1049         if ((ecryptfs_inode_to_lower(inode)
1050              == (struct inode *)candidate_lower_inode))
1051                 return 1;
1052         else
1053                 return 0;
1054 }
1055
1056 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1057 {
1058         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1059         return 0;
1060 }
1061
1062 const struct inode_operations ecryptfs_symlink_iops = {
1063         .readlink = ecryptfs_readlink,
1064         .follow_link = ecryptfs_follow_link,
1065         .put_link = ecryptfs_put_link,
1066         .permission = ecryptfs_permission,
1067         .setattr = ecryptfs_setattr,
1068         .setxattr = ecryptfs_setxattr,
1069         .getxattr = ecryptfs_getxattr,
1070         .listxattr = ecryptfs_listxattr,
1071         .removexattr = ecryptfs_removexattr
1072 };
1073
1074 const struct inode_operations ecryptfs_dir_iops = {
1075         .create = ecryptfs_create,
1076         .lookup = ecryptfs_lookup,
1077         .link = ecryptfs_link,
1078         .unlink = ecryptfs_unlink,
1079         .symlink = ecryptfs_symlink,
1080         .mkdir = ecryptfs_mkdir,
1081         .rmdir = ecryptfs_rmdir,
1082         .mknod = ecryptfs_mknod,
1083         .rename = ecryptfs_rename,
1084         .permission = ecryptfs_permission,
1085         .setattr = ecryptfs_setattr,
1086         .setxattr = ecryptfs_setxattr,
1087         .getxattr = ecryptfs_getxattr,
1088         .listxattr = ecryptfs_listxattr,
1089         .removexattr = ecryptfs_removexattr
1090 };
1091
1092 const struct inode_operations ecryptfs_main_iops = {
1093         .permission = ecryptfs_permission,
1094         .setattr = ecryptfs_setattr,
1095         .setxattr = ecryptfs_setxattr,
1096         .getxattr = ecryptfs_getxattr,
1097         .listxattr = ecryptfs_listxattr,
1098         .removexattr = ecryptfs_removexattr
1099 };