git.oblomov.eu Git - linux-2.6/blob - fs/ecryptfs/inode.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2004 Erez Zadok
   5  * Copyright (C) 2001-2004 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #include <linux/file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/dcache.h>
  30 #include <linux/namei.h>
  31 #include <linux/mount.h>
  32 #include <linux/crypto.h>
  33 #include <linux/fs_stack.h>
  34 #include "ecryptfs_kernel.h"
  35
  36 static struct dentry *lock_parent(struct dentry *dentry)
  37 {
  38         struct dentry *dir;
  39
  40         dir = dget(dentry->d_parent);
  41         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
  42         return dir;
  43 }
  44
  45 static void unlock_parent(struct dentry *dentry)
  46 {
  47         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
  48         dput(dentry->d_parent);
  49 }
  50
  51 static void unlock_dir(struct dentry *dir)
  52 {
  53         mutex_unlock(&dir->d_inode->i_mutex);
  54         dput(dir);
  55 }
  56
  57 /**
  58  * ecryptfs_create_underlying_file
  59  * @lower_dir_inode: inode of the parent in the lower fs of the new file
  60  * @lower_dentry: New file's dentry in the lower fs
  61  * @ecryptfs_dentry: New file's dentry in ecryptfs
  62  * @mode: The mode of the new file
  63  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  64  *
  65  * Creates the file in the lower file system.
  66  *
  67  * Returns zero on success; non-zero on error condition
  68  */
  69 static int
  70 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
  71                                 struct dentry *dentry, int mode,
  72                                 struct nameidata *nd)
  73 {
  74         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  75         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  76         struct dentry *dentry_save;
  77         struct vfsmount *vfsmount_save;
  78         int rc;
  79
  80         dentry_save = nd->dentry;
  81         vfsmount_save = nd->mnt;
  82         nd->dentry = lower_dentry;
  83         nd->mnt = lower_mnt;
  84         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
  85         nd->dentry = dentry_save;
  86         nd->mnt = vfsmount_save;
  87         return rc;
  88 }
  89
  90 /**
  91  * ecryptfs_do_create
  92  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
  93  * @ecryptfs_dentry: New file's dentry in ecryptfs
  94  * @mode: The mode of the new file
  95  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  96  *
  97  * Creates the underlying file and the eCryptfs inode which will link to
  98  * it. It will also update the eCryptfs directory inode to mimic the
  99  * stat of the lower directory inode.
 100  *
 101  * Returns zero on success; non-zero on error condition
 102  */
 103 static int
 104 ecryptfs_do_create(struct inode *directory_inode,
 105                    struct dentry *ecryptfs_dentry, int mode,
 106                    struct nameidata *nd)
 107 {
 108         int rc;
 109         struct dentry *lower_dentry;
 110         struct dentry *lower_dir_dentry;
 111
 112         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 113         lower_dir_dentry = lock_parent(lower_dentry);
 114         if (unlikely(IS_ERR(lower_dir_dentry))) {
 115                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 116                                 "dentry\n");
 117                 rc = PTR_ERR(lower_dir_dentry);
 118                 goto out;
 119         }
 120         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 121                                              ecryptfs_dentry, mode, nd);
 122         if (rc) {
 123                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 124                        "rc = [%d]\n", __FUNCTION__, rc);
 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  *
 145  * This is the code which will grow the file to its correct size.
 146  */
 147 static int grow_file(struct dentry *ecryptfs_dentry)
 148 {
 149         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
 150         struct file fake_file;
 151         struct ecryptfs_file_info tmp_file_info;
 152         char zero_virt[] = { 0x00 };
 153         int rc = 0;
 154
 155         memset(&fake_file, 0, sizeof(fake_file));
 156         fake_file.f_path.dentry = ecryptfs_dentry;
 157         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 158         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 159         ecryptfs_set_file_lower(
 160                 &fake_file,
 161                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
 162         rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
 163         i_size_write(ecryptfs_inode, 0);
 164         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
 165         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
 166                 ECRYPTFS_NEW_FILE;
 167         return rc;
 168 }
 169
 170 /**
 171  * ecryptfs_initialize_file
 172  *
 173  * Cause the file to be changed from a basic empty file to an ecryptfs
 174  * file with a header and first data page.
 175  *
 176  * Returns zero on success
 177  */
 178 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 179 {
 180         struct ecryptfs_crypt_stat *crypt_stat =
 181                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
 182         int rc = 0;
 183
 184         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 185                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 186                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 187                 goto out;
 188         }
 189         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
 190         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 191         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 192         if (rc) {
 193                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 194                                 "context; rc = [%d]\n", rc);
 195                 goto out;
 196         }
 197         rc = ecryptfs_write_metadata(ecryptfs_dentry);
 198         if (rc) {
 199                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 200                 goto out;
 201         }
 202         rc = grow_file(ecryptfs_dentry);
 203         if (rc)
 204                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
 205 out:
 206         return rc;
 207 }
 208
 209 /**
 210  * ecryptfs_create
 211  * @dir: The inode of the directory in which to create the file.
 212  * @dentry: The eCryptfs dentry
 213  * @mode: The mode of the new file.
 214  * @nd: nameidata
 215  *
 216  * Creates a new file.
 217  *
 218  * Returns zero on success; non-zero on error condition
 219  */
 220 static int
 221 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 222                 int mode, struct nameidata *nd)
 223 {
 224         int rc;
 225
 226         /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
 227          * the crypt_stat->lower_file (persistent file) */
 228         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 229         if (unlikely(rc)) {
 230                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 231                                 "lower filesystem\n");
 232                 goto out;
 233         }
 234         /* At this point, a file exists on "disk"; we need to make sure
 235          * that this on disk file is prepared to be an ecryptfs file */
 236         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 237 out:
 238         return rc;
 239 }
 240
 241 /**
 242  * ecryptfs_lookup
 243  * @dir: inode
 244  * @dentry: The dentry
 245  * @nd: nameidata, may be NULL
 246  *
 247  * Find a file on disk. If the file does not exist, then we'll add it to the
 248  * dentry cache and continue on to read it from the disk.
 249  */
 250 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 251                                       struct nameidata *nd)
 252 {
 253         int rc = 0;
 254         struct dentry *lower_dir_dentry;
 255         struct dentry *lower_dentry;
 256         struct vfsmount *lower_mnt;
 257         char *encoded_name;
 258         int encoded_namelen;
 259         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 260         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 261         char *page_virt = NULL;
 262         struct inode *lower_inode;
 263         u64 file_size;
 264
 265         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 266         dentry->d_op = &ecryptfs_dops;
 267         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 268             || (dentry->d_name.len == 2
 269                 && !strcmp(dentry->d_name.name, ".."))) {
 270                 d_drop(dentry);
 271                 goto out;
 272         }
 273         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 274                                                    dentry->d_name.name,
 275                                                    dentry->d_name.len,
 276                                                    &encoded_name);
 277         if (encoded_namelen < 0) {
 278                 rc = encoded_namelen;
 279                 d_drop(dentry);
 280                 goto out;
 281         }
 282         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 283                         "= [%d]\n", encoded_name, encoded_namelen);
 284         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 285                                       encoded_namelen - 1);
 286         kfree(encoded_name);
 287         if (IS_ERR(lower_dentry)) {
 288                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 289                 rc = PTR_ERR(lower_dentry);
 290                 d_drop(dentry);
 291                 goto out;
 292         }
 293         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 294         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 295                 "d_name.name = [%s]\n", lower_dentry,
 296                 lower_dentry->d_name.name);
 297         lower_inode = lower_dentry->d_inode;
 298         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 299         BUG_ON(!atomic_read(&lower_dentry->d_count));
 300         ecryptfs_set_dentry_private(dentry,
 301                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 302                                                      GFP_KERNEL));
 303         if (!ecryptfs_dentry_to_private(dentry)) {
 304                 rc = -ENOMEM;
 305                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 306                                 "to allocate ecryptfs_dentry_info struct\n");
 307                 goto out_dput;
 308         }
 309         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 310         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 311         if (!lower_dentry->d_inode) {
 312                 /* We want to add because we couldn't find in lower */
 313                 d_add(dentry, NULL);
 314                 goto out;
 315         }
 316         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 317         if (rc) {
 318                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 319                 goto out_dput;
 320         }
 321         if (S_ISDIR(lower_inode->i_mode)) {
 322                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 323                 goto out;
 324         }
 325         if (S_ISLNK(lower_inode->i_mode)) {
 326                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 327                 goto out;
 328         }
 329         if (special_file(lower_inode->i_mode)) {
 330                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
 331                 goto out;
 332         }
 333         if (!nd) {
 334                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 335                                 "as we *think* we are about to unlink\n");
 336                 goto out;
 337         }
 338         /* Released in this function */
 339         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 340                                       GFP_USER);
 341         if (!page_virt) {
 342                 rc = -ENOMEM;
 343                 ecryptfs_printk(KERN_ERR,
 344                                 "Cannot ecryptfs_kmalloc a page\n");
 345                 goto out_dput;
 346         }
 347         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 348         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 349                 ecryptfs_set_default_sizes(crypt_stat);
 350         rc = ecryptfs_read_and_validate_header_region(page_virt,
 351                                                       dentry->d_inode);
 352         if (rc) {
 353                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 354                 if (rc) {
 355                         printk(KERN_DEBUG "Valid metadata not found in header "
 356                                "region or xattr region; treating file as "
 357                                "unencrypted\n");
 358                         rc = 0;
 359                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 360                         goto out;
 361                 }
 362                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 363         }
 364         mount_crypt_stat = &ecryptfs_superblock_to_private(
 365                 dentry->d_sb)->mount_crypt_stat;
 366         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 367                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 368                         file_size = ((crypt_stat->extent_size
 369                                       * crypt_stat->num_header_extents_at_front)
 370                                      + i_size_read(lower_dentry->d_inode));
 371                 else
 372                         file_size = i_size_read(lower_dentry->d_inode);
 373         } else {
 374                 memcpy(&file_size, page_virt, sizeof(file_size));
 375                 file_size = be64_to_cpu(file_size);
 376         }
 377         i_size_write(dentry->d_inode, (loff_t)file_size);
 378         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 379         goto out;
 380
 381 out_dput:
 382         dput(lower_dentry);
 383         d_drop(dentry);
 384 out:
 385         return ERR_PTR(rc);
 386 }
 387
 388 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 389                          struct dentry *new_dentry)
 390 {
 391         struct dentry *lower_old_dentry;
 392         struct dentry *lower_new_dentry;
 393         struct dentry *lower_dir_dentry;
 394         u64 file_size_save;
 395         int rc;
 396
 397         file_size_save = i_size_read(old_dentry->d_inode);
 398         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 399         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 400         dget(lower_old_dentry);
 401         dget(lower_new_dentry);
 402         lower_dir_dentry = lock_parent(lower_new_dentry);
 403         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 404                       lower_new_dentry);
 405         if (rc || !lower_new_dentry->d_inode)
 406                 goto out_lock;
 407         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 408         if (rc)
 409                 goto out_lock;
 410         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 411         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 412         old_dentry->d_inode->i_nlink =
 413                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 414         i_size_write(new_dentry->d_inode, file_size_save);
 415 out_lock:
 416         unlock_dir(lower_dir_dentry);
 417         dput(lower_new_dentry);
 418         dput(lower_old_dentry);
 419         d_drop(lower_old_dentry);
 420         d_drop(new_dentry);
 421         d_drop(old_dentry);
 422         return rc;
 423 }
 424
 425 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 426 {
 427         int rc = 0;
 428         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 429         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 430
 431         lock_parent(lower_dentry);
 432         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 433         if (rc) {
 434                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 435                 goto out_unlock;
 436         }
 437         fsstack_copy_attr_times(dir, lower_dir_inode);
 438         dentry->d_inode->i_nlink =
 439                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 440         dentry->d_inode->i_ctime = dir->i_ctime;
 441         d_drop(dentry);
 442 out_unlock:
 443         unlock_parent(lower_dentry);
 444         return rc;
 445 }
 446
 447 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 448                             const char *symname)
 449 {
 450         int rc;
 451         struct dentry *lower_dentry;
 452         struct dentry *lower_dir_dentry;
 453         umode_t mode;
 454         char *encoded_symname;
 455         int encoded_symlen;
 456         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 457
 458         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 459         dget(lower_dentry);
 460         lower_dir_dentry = lock_parent(lower_dentry);
 461         mode = S_IALLUGO;
 462         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 463                                                   strlen(symname),
 464                                                   &encoded_symname);
 465         if (encoded_symlen < 0) {
 466                 rc = encoded_symlen;
 467                 goto out_lock;
 468         }
 469         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 470                          encoded_symname, mode);
 471         kfree(encoded_symname);
 472         if (rc || !lower_dentry->d_inode)
 473                 goto out_lock;
 474         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 475         if (rc)
 476                 goto out_lock;
 477         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 478         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 479 out_lock:
 480         unlock_dir(lower_dir_dentry);
 481         dput(lower_dentry);
 482         if (!dentry->d_inode)
 483                 d_drop(dentry);
 484         return rc;
 485 }
 486
 487 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 488 {
 489         int rc;
 490         struct dentry *lower_dentry;
 491         struct dentry *lower_dir_dentry;
 492
 493         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 494         lower_dir_dentry = lock_parent(lower_dentry);
 495         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 496         if (rc || !lower_dentry->d_inode)
 497                 goto out;
 498         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 499         if (rc)
 500                 goto out;
 501         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 502         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 503         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 504 out:
 505         unlock_dir(lower_dir_dentry);
 506         if (!dentry->d_inode)
 507                 d_drop(dentry);
 508         return rc;
 509 }
 510
 511 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 512 {
 513         struct dentry *lower_dentry;
 514         struct dentry *lower_dir_dentry;
 515         int rc;
 516
 517         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 518         dget(dentry);
 519         lower_dir_dentry = lock_parent(lower_dentry);
 520         dget(lower_dentry);
 521         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 522         dput(lower_dentry);
 523         if (!rc)
 524                 d_delete(lower_dentry);
 525         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 526         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 527         unlock_dir(lower_dir_dentry);
 528         if (!rc)
 529                 d_drop(dentry);
 530         dput(dentry);
 531         return rc;
 532 }
 533
 534 static int
 535 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 536 {
 537         int rc;
 538         struct dentry *lower_dentry;
 539         struct dentry *lower_dir_dentry;
 540
 541         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 542         lower_dir_dentry = lock_parent(lower_dentry);
 543         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 544         if (rc || !lower_dentry->d_inode)
 545                 goto out;
 546         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 547         if (rc)
 548                 goto out;
 549         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 550         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 551 out:
 552         unlock_dir(lower_dir_dentry);
 553         if (!dentry->d_inode)
 554                 d_drop(dentry);
 555         return rc;
 556 }
 557
 558 static int
 559 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 560                 struct inode *new_dir, struct dentry *new_dentry)
 561 {
 562         int rc;
 563         struct dentry *lower_old_dentry;
 564         struct dentry *lower_new_dentry;
 565         struct dentry *lower_old_dir_dentry;
 566         struct dentry *lower_new_dir_dentry;
 567
 568         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 569         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 570         dget(lower_old_dentry);
 571         dget(lower_new_dentry);
 572         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 573         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 574         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 575         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 576                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 577         if (rc)
 578                 goto out_lock;
 579         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 580         if (new_dir != old_dir)
 581                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 582 out_lock:
 583         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 584         dput(lower_new_dentry->d_parent);
 585         dput(lower_old_dentry->d_parent);
 586         dput(lower_new_dentry);
 587         dput(lower_old_dentry);
 588         return rc;
 589 }
 590
 591 static int
 592 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 593 {
 594         int rc;
 595         struct dentry *lower_dentry;
 596         char *decoded_name;
 597         char *lower_buf;
 598         mm_segment_t old_fs;
 599         struct ecryptfs_crypt_stat *crypt_stat;
 600
 601         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 602         if (!lower_dentry->d_inode->i_op ||
 603             !lower_dentry->d_inode->i_op->readlink) {
 604                 rc = -EINVAL;
 605                 goto out;
 606         }
 607         /* Released in this function */
 608         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 609         if (lower_buf == NULL) {
 610                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 611                 rc = -ENOMEM;
 612                 goto out;
 613         }
 614         old_fs = get_fs();
 615         set_fs(get_ds());
 616         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 617                         "lower_dentry->d_name.name = [%s]\n",
 618                         lower_dentry->d_name.name);
 619         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 620                                                    (char __user *)lower_buf,
 621                                                    bufsiz);
 622         set_fs(old_fs);
 623         if (rc >= 0) {
 624                 crypt_stat = NULL;
 625                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 626                                               &decoded_name);
 627                 if (rc == -ENOMEM)
 628                         goto out_free_lower_buf;
 629                 if (rc > 0) {
 630                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 631                                         "to userspace: [%*s]\n", rc,
 632                                         decoded_name);
 633                         if (copy_to_user(buf, decoded_name, rc))
 634                                 rc = -EFAULT;
 635                 }
 636                 kfree(decoded_name);
 637                 fsstack_copy_attr_atime(dentry->d_inode,
 638                                         lower_dentry->d_inode);
 639         }
 640 out_free_lower_buf:
 641         kfree(lower_buf);
 642 out:
 643         return rc;
 644 }
 645
 646 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 647 {
 648         char *buf;
 649         int len = PAGE_SIZE, rc;
 650         mm_segment_t old_fs;
 651
 652         /* Released in ecryptfs_put_link(); only release here on error */
 653         buf = kmalloc(len, GFP_KERNEL);
 654         if (!buf) {
 655                 rc = -ENOMEM;
 656                 goto out;
 657         }
 658         old_fs = get_fs();
 659         set_fs(get_ds());
 660         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 661                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 662         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 663         buf[rc] = '\0';
 664         set_fs(old_fs);
 665         if (rc < 0)
 666                 goto out_free;
 667         rc = 0;
 668         nd_set_link(nd, buf);
 669         goto out;
 670 out_free:
 671         kfree(buf);
 672 out:
 673         return ERR_PTR(rc);
 674 }
 675
 676 static void
 677 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 678 {
 679         /* Free the char* */
 680         kfree(nd_get_link(nd));
 681 }
 682
 683 /**
 684  * upper_size_to_lower_size
 685  * @crypt_stat: Crypt_stat associated with file
 686  * @upper_size: Size of the upper file
 687  *
 688  * Calculate the requried size of the lower file based on the
 689  * specified size of the upper file. This calculation is based on the
 690  * number of headers in the underlying file and the extent size.
 691  *
 692  * Returns Calculated size of the lower file.
 693  */
 694 static loff_t
 695 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 696                          loff_t upper_size)
 697 {
 698         loff_t lower_size;
 699
 700         lower_size = (crypt_stat->extent_size
 701                       * crypt_stat->num_header_extents_at_front);
 702         if (upper_size != 0) {
 703                 loff_t num_extents;
 704
 705                 num_extents = upper_size >> crypt_stat->extent_shift;
 706                 if (upper_size & ~crypt_stat->extent_mask)
 707                         num_extents++;
 708                 lower_size += (num_extents * crypt_stat->extent_size);
 709         }
 710         return lower_size;
 711 }
 712
 713 /**
 714  * ecryptfs_truncate
 715  * @dentry: The ecryptfs layer dentry
 716  * @new_length: The length to expand the file to
 717  *
 718  * Function to handle truncations modifying the size of the file. Note
 719  * that the file sizes are interpolated. When expanding, we are simply
 720  * writing strings of 0's out. When truncating, we need to modify the
 721  * underlying file size according to the page index interpolations.
 722  *
 723  * Returns zero on success; non-zero otherwise
 724  */
 725 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 726 {
 727         int rc = 0;
 728         struct inode *inode = dentry->d_inode;
 729         struct dentry *lower_dentry;
 730         struct file fake_ecryptfs_file;
 731         struct ecryptfs_crypt_stat *crypt_stat;
 732         loff_t i_size = i_size_read(inode);
 733         loff_t lower_size_before_truncate;
 734         loff_t lower_size_after_truncate;
 735
 736         if (unlikely((new_length == i_size)))
 737                 goto out;
 738         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 739         /* Set up a fake ecryptfs file, this is used to interface with
 740          * the file in the underlying filesystem so that the
 741          * truncation has an effect there as well. */
 742         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 743         fake_ecryptfs_file.f_path.dentry = dentry;
 744         /* Released at out_free: label */
 745         ecryptfs_set_file_private(&fake_ecryptfs_file,
 746                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 747                                                    GFP_KERNEL));
 748         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 749                 rc = -ENOMEM;
 750                 goto out;
 751         }
 752         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 753         ecryptfs_set_file_lower(
 754                 &fake_ecryptfs_file,
 755                 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
 756         /* Switch on growing or shrinking file */
 757         if (new_length > i_size) {
 758                 char zero[] = { 0x00 };
 759
 760                 /* Write a single 0 at the last position of the file;
 761                  * this triggers code that will fill in 0's throughout
 762                  * the intermediate portion of the previous end of the
 763                  * file and the new and of the file */
 764                 rc = ecryptfs_write(&fake_ecryptfs_file, zero,
 765                                     (new_length - 1), 1);
 766         } else { /* new_length < i_size_read(inode) */
 767                 /* We're chopping off all the pages down do the page
 768                  * in which new_length is located. Fill in the end of
 769                  * that page from (new_length & ~PAGE_CACHE_MASK) to
 770                  * PAGE_CACHE_SIZE with zeros. */
 771                 size_t num_zeros = (PAGE_CACHE_SIZE
 772                                     - (new_length & ~PAGE_CACHE_MASK));
 773
 774                 if (num_zeros) {
 775                         char *zeros_virt;
 776
 777                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 778                         if (!zeros_virt) {
 779                                 rc = -ENOMEM;
 780                                 goto out_free;
 781                         }
 782                         rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
 783                                             new_length, num_zeros);
 784                         kfree(zeros_virt);
 785                         if (rc) {
 786                                 printk(KERN_ERR "Error attempting to zero out "
 787                                        "the remainder of the end page on "
 788                                        "reducing truncate; rc = [%d]\n", rc);
 789                                 goto out_free;
 790                         }
 791                 }
 792                 vmtruncate(inode, new_length);
 793                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 794                 if (rc) {
 795                         printk(KERN_ERR "Problem with "
 796                                "ecryptfs_write_inode_size_to_metadata; "
 797                                "rc = [%d]\n", rc);
 798                         goto out_free;
 799                 }
 800                 /* We are reducing the size of the ecryptfs file, and need to
 801                  * know if we need to reduce the size of the lower file. */
 802                 lower_size_before_truncate =
 803                     upper_size_to_lower_size(crypt_stat, i_size);
 804                 lower_size_after_truncate =
 805                     upper_size_to_lower_size(crypt_stat, new_length);
 806                 if (lower_size_after_truncate < lower_size_before_truncate)
 807                         vmtruncate(lower_dentry->d_inode,
 808                                    lower_size_after_truncate);
 809         }
 810 out_free:
 811         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 812                 kmem_cache_free(ecryptfs_file_info_cache,
 813                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 814 out:
 815         return rc;
 816 }
 817
 818 static int
 819 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 820 {
 821         int rc;
 822
 823         if (nd) {
 824                 struct vfsmount *vfsmnt_save = nd->mnt;
 825                 struct dentry *dentry_save = nd->dentry;
 826
 827                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 828                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 829                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 830                 nd->mnt = vfsmnt_save;
 831                 nd->dentry = dentry_save;
 832         } else
 833                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 834         return rc;
 835 }
 836
 837 /**
 838  * ecryptfs_setattr
 839  * @dentry: dentry handle to the inode to modify
 840  * @ia: Structure with flags of what to change and values
 841  *
 842  * Updates the metadata of an inode. If the update is to the size
 843  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 844  * of both the ecryptfs inode and the lower inode.
 845  *
 846  * All other metadata changes will be passed right to the lower filesystem,
 847  * and we will just update our inode to look like the lower.
 848  */
 849 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 850 {
 851         int rc = 0;
 852         struct dentry *lower_dentry;
 853         struct inode *inode;
 854         struct inode *lower_inode;
 855         struct ecryptfs_crypt_stat *crypt_stat;
 856
 857         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 858         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 859                 ecryptfs_init_crypt_stat(crypt_stat);
 860         inode = dentry->d_inode;
 861         lower_inode = ecryptfs_inode_to_lower(inode);
 862         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 863         mutex_lock(&crypt_stat->cs_mutex);
 864         if (S_ISDIR(dentry->d_inode->i_mode))
 865                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 866         else if (S_ISREG(dentry->d_inode->i_mode)
 867                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 868                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 869                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 870
 871                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 872                         dentry->d_sb)->mount_crypt_stat;
 873                 rc = ecryptfs_read_metadata(dentry);
 874                 if (rc) {
 875                         if (!(mount_crypt_stat->flags
 876                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 877                                 rc = -EIO;
 878                                 printk(KERN_WARNING "Attempt to read file that "
 879                                        "is not in a valid eCryptfs format, "
 880                                        "and plaintext passthrough mode is not "
 881                                        "enabled; returning -EIO\n");
 882
 883                                 mutex_unlock(&crypt_stat->cs_mutex);
 884                                 goto out;
 885                         }
 886                         rc = 0;
 887                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 888                         mutex_unlock(&crypt_stat->cs_mutex);
 889                         goto out;
 890                 }
 891         }
 892         mutex_unlock(&crypt_stat->cs_mutex);
 893         if (ia->ia_valid & ATTR_SIZE) {
 894                 ecryptfs_printk(KERN_DEBUG,
 895                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 896                                 ia->ia_valid, ATTR_SIZE);
 897                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 898                 /* ecryptfs_truncate handles resizing of the lower file */
 899                 ia->ia_valid &= ~ATTR_SIZE;
 900                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 901                                 ia->ia_valid);
 902                 if (rc < 0)
 903                         goto out;
 904         }
 905
 906         /*
 907          * mode change is for clearing setuid/setgid bits. Allow lower fs
 908          * to interpret this in its own way.
 909          */
 910         if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 911                 ia->ia_valid &= ~ATTR_MODE;
 912
 913         rc = notify_change(lower_dentry, ia);
 914 out:
 915         fsstack_copy_attr_all(inode, lower_inode, NULL);
 916         return rc;
 917 }
 918
 919 int
 920 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 921                   size_t size, int flags)
 922 {
 923         int rc = 0;
 924         struct dentry *lower_dentry;
 925
 926         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 927         if (!lower_dentry->d_inode->i_op->setxattr) {
 928                 rc = -ENOSYS;
 929                 goto out;
 930         }
 931         mutex_lock(&lower_dentry->d_inode->i_mutex);
 932         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 933                                                    size, flags);
 934         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 935 out:
 936         return rc;
 937 }
 938
 939 ssize_t
 940 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
 941                         void *value, size_t size)
 942 {
 943         int rc = 0;
 944
 945         if (!lower_dentry->d_inode->i_op->getxattr) {
 946                 rc = -ENOSYS;
 947                 goto out;
 948         }
 949         mutex_lock(&lower_dentry->d_inode->i_mutex);
 950         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 951                                                    size);
 952         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 953 out:
 954         return rc;
 955 }
 956
 957 ssize_t
 958 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 959                   size_t size)
 960 {
 961         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
 962                                        value, size);
 963 }
 964
 965 static ssize_t
 966 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 967 {
 968         int rc = 0;
 969         struct dentry *lower_dentry;
 970
 971         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 972         if (!lower_dentry->d_inode->i_op->listxattr) {
 973                 rc = -ENOSYS;
 974                 goto out;
 975         }
 976         mutex_lock(&lower_dentry->d_inode->i_mutex);
 977         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
 978         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 979 out:
 980         return rc;
 981 }
 982
 983 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
 984 {
 985         int rc = 0;
 986         struct dentry *lower_dentry;
 987
 988         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 989         if (!lower_dentry->d_inode->i_op->removexattr) {
 990                 rc = -ENOSYS;
 991                 goto out;
 992         }
 993         mutex_lock(&lower_dentry->d_inode->i_mutex);
 994         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
 995         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 996 out:
 997         return rc;
 998 }
 999
1000 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1001 {
1002         if ((ecryptfs_inode_to_lower(inode)
1003              == (struct inode *)candidate_lower_inode))
1004                 return 1;
1005         else
1006                 return 0;
1007 }
1008
1009 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1010 {
1011         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1012         return 0;
1013 }
1014
1015 const struct inode_operations ecryptfs_symlink_iops = {
1016         .readlink = ecryptfs_readlink,
1017         .follow_link = ecryptfs_follow_link,
1018         .put_link = ecryptfs_put_link,
1019         .permission = ecryptfs_permission,
1020         .setattr = ecryptfs_setattr,
1021         .setxattr = ecryptfs_setxattr,
1022         .getxattr = ecryptfs_getxattr,
1023         .listxattr = ecryptfs_listxattr,
1024         .removexattr = ecryptfs_removexattr
1025 };
1026
1027 const struct inode_operations ecryptfs_dir_iops = {
1028         .create = ecryptfs_create,
1029         .lookup = ecryptfs_lookup,
1030         .link = ecryptfs_link,
1031         .unlink = ecryptfs_unlink,
1032         .symlink = ecryptfs_symlink,
1033         .mkdir = ecryptfs_mkdir,
1034         .rmdir = ecryptfs_rmdir,
1035         .mknod = ecryptfs_mknod,
1036         .rename = ecryptfs_rename,
1037         .permission = ecryptfs_permission,
1038         .setattr = ecryptfs_setattr,
1039         .setxattr = ecryptfs_setxattr,
1040         .getxattr = ecryptfs_getxattr,
1041         .listxattr = ecryptfs_listxattr,
1042         .removexattr = ecryptfs_removexattr
1043 };
1044
1045 const struct inode_operations ecryptfs_main_iops = {
1046         .permission = ecryptfs_permission,
1047         .setattr = ecryptfs_setattr,
1048         .setxattr = ecryptfs_setxattr,
1049         .getxattr = ecryptfs_getxattr,
1050         .listxattr = ecryptfs_listxattr,
1051         .removexattr = ecryptfs_removexattr
1052 };