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 <linux/slab.h>
  35 #include <linux/xattr.h>
  36 #include <asm/unaligned.h>
  37 #include "ecryptfs_kernel.h"
  38
  39 static struct dentry *lock_parent(struct dentry *dentry)
  40 {
  41         struct dentry *dir;
  42
  43         dir = dget_parent(dentry);
  44         mutex_lock_nested(&(d_inode(dir)->i_mutex), I_MUTEX_PARENT);
  45         return dir;
  46 }
  47
  48 static void unlock_dir(struct dentry *dir)
  49 {
  50         mutex_unlock(&d_inode(dir)->i_mutex);
  51         dput(dir);
  52 }
  53
  54 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
  55 {
  56         return ecryptfs_inode_to_lower(inode) == lower_inode;
  57 }
  58
  59 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
  60 {
  61         struct inode *lower_inode = opaque;
  62
  63         ecryptfs_set_inode_lower(inode, lower_inode);
  64         fsstack_copy_attr_all(inode, lower_inode);
  65         /* i_size will be overwritten for encrypted regular files */
  66         fsstack_copy_inode_size(inode, lower_inode);
  67         inode->i_ino = lower_inode->i_ino;
  68         inode->i_version++;
  69         inode->i_mapping->a_ops = &ecryptfs_aops;
  70
  71         if (S_ISLNK(inode->i_mode))
  72                 inode->i_op = &ecryptfs_symlink_iops;
  73         else if (S_ISDIR(inode->i_mode))
  74                 inode->i_op = &ecryptfs_dir_iops;
  75         else
  76                 inode->i_op = &ecryptfs_main_iops;
  77
  78         if (S_ISDIR(inode->i_mode))
  79                 inode->i_fop = &ecryptfs_dir_fops;
  80         else if (special_file(inode->i_mode))
  81                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
  82         else
  83                 inode->i_fop = &ecryptfs_main_fops;
  84
  85         return 0;
  86 }
  87
  88 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  89                                           struct super_block *sb)
  90 {
  91         struct inode *inode;
  92
  93         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  94                 return ERR_PTR(-EXDEV);
  95         if (!igrab(lower_inode))
  96                 return ERR_PTR(-ESTALE);
  97         inode = iget5_locked(sb, (unsigned long)lower_inode,
  98                              ecryptfs_inode_test, ecryptfs_inode_set,
  99                              lower_inode);
 100         if (!inode) {
 101                 iput(lower_inode);
 102                 return ERR_PTR(-EACCES);
 103         }
 104         if (!(inode->i_state & I_NEW))
 105                 iput(lower_inode);
 106
 107         return inode;
 108 }
 109
 110 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 111                                  struct super_block *sb)
 112 {
 113         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 114
 115         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 116                 unlock_new_inode(inode);
 117
 118         return inode;
 119 }
 120
 121 /**
 122  * ecryptfs_interpose
 123  * @lower_dentry: Existing dentry in the lower filesystem
 124  * @dentry: ecryptfs' dentry
 125  * @sb: ecryptfs's super_block
 126  *
 127  * Interposes upper and lower dentries.
 128  *
 129  * Returns zero on success; non-zero otherwise
 130  */
 131 static int ecryptfs_interpose(struct dentry *lower_dentry,
 132                               struct dentry *dentry, struct super_block *sb)
 133 {
 134         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 135
 136         if (IS_ERR(inode))
 137                 return PTR_ERR(inode);
 138         d_instantiate(dentry, inode);
 139
 140         return 0;
 141 }
 142
 143 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 144                               struct inode *inode)
 145 {
 146         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 147         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 148         struct dentry *lower_dir_dentry;
 149         int rc;
 150
 151         dget(lower_dentry);
 152         lower_dir_dentry = lock_parent(lower_dentry);
 153         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 154         if (rc) {
 155                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 156                 goto out_unlock;
 157         }
 158         fsstack_copy_attr_times(dir, lower_dir_inode);
 159         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 160         inode->i_ctime = dir->i_ctime;
 161         d_drop(dentry);
 162 out_unlock:
 163         unlock_dir(lower_dir_dentry);
 164         dput(lower_dentry);
 165         return rc;
 166 }
 167
 168 /**
 169  * ecryptfs_do_create
 170  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 171  * @ecryptfs_dentry: New file's dentry in ecryptfs
 172  * @mode: The mode of the new file
 173  *
 174  * Creates the underlying file and the eCryptfs inode which will link to
 175  * it. It will also update the eCryptfs directory inode to mimic the
 176  * stat of the lower directory inode.
 177  *
 178  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 179  */
 180 static struct inode *
 181 ecryptfs_do_create(struct inode *directory_inode,
 182                    struct dentry *ecryptfs_dentry, umode_t mode)
 183 {
 184         int rc;
 185         struct dentry *lower_dentry;
 186         struct dentry *lower_dir_dentry;
 187         struct inode *inode;
 188
 189         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 190         lower_dir_dentry = lock_parent(lower_dentry);
 191         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 192         if (rc) {
 193                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 194                        "rc = [%d]\n", __func__, rc);
 195                 inode = ERR_PTR(rc);
 196                 goto out_lock;
 197         }
 198         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 199                                      directory_inode->i_sb);
 200         if (IS_ERR(inode)) {
 201                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 202                 goto out_lock;
 203         }
 204         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 205         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 206 out_lock:
 207         unlock_dir(lower_dir_dentry);
 208         return inode;
 209 }
 210
 211 /**
 212  * ecryptfs_initialize_file
 213  *
 214  * Cause the file to be changed from a basic empty file to an ecryptfs
 215  * file with a header and first data page.
 216  *
 217  * Returns zero on success
 218  */
 219 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 220                              struct inode *ecryptfs_inode)
 221 {
 222         struct ecryptfs_crypt_stat *crypt_stat =
 223                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 224         int rc = 0;
 225
 226         if (S_ISDIR(ecryptfs_inode->i_mode)) {
 227                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 228                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 229                 goto out;
 230         }
 231         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 232         rc = ecryptfs_new_file_context(ecryptfs_inode);
 233         if (rc) {
 234                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 235                                 "context; rc = [%d]\n", rc);
 236                 goto out;
 237         }
 238         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 239         if (rc) {
 240                 printk(KERN_ERR "%s: Error attempting to initialize "
 241                         "the lower file for the dentry with name "
 242                         "[%pd]; rc = [%d]\n", __func__,
 243                         ecryptfs_dentry, rc);
 244                 goto out;
 245         }
 246         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 247         if (rc)
 248                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 249         ecryptfs_put_lower_file(ecryptfs_inode);
 250 out:
 251         return rc;
 252 }
 253
 254 /**
 255  * ecryptfs_create
 256  * @dir: The inode of the directory in which to create the file.
 257  * @dentry: The eCryptfs dentry
 258  * @mode: The mode of the new file.
 259  *
 260  * Creates a new file.
 261  *
 262  * Returns zero on success; non-zero on error condition
 263  */
 264 static int
 265 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 266                 umode_t mode, bool excl)
 267 {
 268         struct inode *ecryptfs_inode;
 269         int rc;
 270
 271         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 272                                             mode);
 273         if (IS_ERR(ecryptfs_inode)) {
 274                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 275                                 "lower filesystem\n");
 276                 rc = PTR_ERR(ecryptfs_inode);
 277                 goto out;
 278         }
 279         /* At this point, a file exists on "disk"; we need to make sure
 280          * that this on disk file is prepared to be an ecryptfs file */
 281         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 282         if (rc) {
 283                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 284                                    ecryptfs_inode);
 285                 make_bad_inode(ecryptfs_inode);
 286                 unlock_new_inode(ecryptfs_inode);
 287                 iput(ecryptfs_inode);
 288                 goto out;
 289         }
 290         d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
 291 out:
 292         return rc;
 293 }
 294
 295 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 296 {
 297         struct ecryptfs_crypt_stat *crypt_stat;
 298         int rc;
 299
 300         rc = ecryptfs_get_lower_file(dentry, inode);
 301         if (rc) {
 302                 printk(KERN_ERR "%s: Error attempting to initialize "
 303                         "the lower file for the dentry with name "
 304                         "[%pd]; rc = [%d]\n", __func__,
 305                         dentry, rc);
 306                 return rc;
 307         }
 308
 309         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 310         /* TODO: lock for crypt_stat comparison */
 311         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 312                 ecryptfs_set_default_sizes(crypt_stat);
 313
 314         rc = ecryptfs_read_and_validate_header_region(inode);
 315         ecryptfs_put_lower_file(inode);
 316         if (rc) {
 317                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
 318                 if (!rc)
 319                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 320         }
 321
 322         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
 323         return 0;
 324 }
 325
 326 /**
 327  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 328  */
 329 static int ecryptfs_lookup_interpose(struct dentry *dentry,
 330                                      struct dentry *lower_dentry,
 331                                      struct inode *dir_inode)
 332 {
 333         struct inode *inode, *lower_inode;
 334         struct ecryptfs_dentry_info *dentry_info;
 335         struct vfsmount *lower_mnt;
 336         int rc = 0;
 337
 338         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 339         if (!dentry_info) {
 340                 printk(KERN_ERR "%s: Out of memory whilst attempting "
 341                        "to allocate ecryptfs_dentry_info struct\n",
 342                         __func__);
 343                 dput(lower_dentry);
 344                 return -ENOMEM;
 345         }
 346
 347         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 348         fsstack_copy_attr_atime(dir_inode, d_inode(lower_dentry->d_parent));
 349         BUG_ON(!d_count(lower_dentry));
 350
 351         ecryptfs_set_dentry_private(dentry, dentry_info);
 352         dentry_info->lower_path.mnt = lower_mnt;
 353         dentry_info->lower_path.dentry = lower_dentry;
 354
 355         /*
 356          * negative dentry can go positive under us here - its parent is not
 357          * locked.  That's OK and that could happen just as we return from
 358          * ecryptfs_lookup() anyway.  Just need to be careful and fetch
 359          * ->d_inode only once - it's not stable here.
 360          */
 361         lower_inode = READ_ONCE(lower_dentry->d_inode);
 362
 363         if (!lower_inode) {
 364                 /* We want to add because we couldn't find in lower */
 365                 d_add(dentry, NULL);
 366                 return 0;
 367         }
 368         inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
 369         if (IS_ERR(inode)) {
 370                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 371                        __func__, PTR_ERR(inode));
 372                 return PTR_ERR(inode);
 373         }
 374         if (S_ISREG(inode->i_mode)) {
 375                 rc = ecryptfs_i_size_read(dentry, inode);
 376                 if (rc) {
 377                         make_bad_inode(inode);
 378                         return rc;
 379                 }
 380         }
 381
 382         if (inode->i_state & I_NEW)
 383                 unlock_new_inode(inode);
 384         d_add(dentry, inode);
 385
 386         return rc;
 387 }
 388
 389 /**
 390  * ecryptfs_lookup
 391  * @ecryptfs_dir_inode: The eCryptfs directory inode
 392  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 393  * @flags: lookup flags
 394  *
 395  * Find a file on disk. If the file does not exist, then we'll add it to the
 396  * dentry cache and continue on to read it from the disk.
 397  */
 398 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 399                                       struct dentry *ecryptfs_dentry,
 400                                       unsigned int flags)
 401 {
 402         char *encrypted_and_encoded_name = NULL;
 403         size_t encrypted_and_encoded_name_size;
 404         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 405         struct dentry *lower_dir_dentry, *lower_dentry;
 406         int rc = 0;
 407
 408         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 409         mutex_lock(&d_inode(lower_dir_dentry)->i_mutex);
 410         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
 411                                       lower_dir_dentry,
 412                                       ecryptfs_dentry->d_name.len);
 413         mutex_unlock(&d_inode(lower_dir_dentry)->i_mutex);
 414         if (IS_ERR(lower_dentry)) {
 415                 rc = PTR_ERR(lower_dentry);
 416                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 417                                 "[%d] on lower_dentry = [%pd]\n", __func__, rc,
 418                                 ecryptfs_dentry);
 419                 goto out;
 420         }
 421         if (d_really_is_positive(lower_dentry))
 422                 goto interpose;
 423         mount_crypt_stat = &ecryptfs_superblock_to_private(
 424                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 425         if (!(mount_crypt_stat
 426             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
 427                 goto interpose;
 428         dput(lower_dentry);
 429         rc = ecryptfs_encrypt_and_encode_filename(
 430                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
 431                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
 432                 ecryptfs_dentry->d_name.len);
 433         if (rc) {
 434                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 435                        "filename; rc = [%d]\n", __func__, rc);
 436                 goto out;
 437         }
 438         mutex_lock(&d_inode(lower_dir_dentry)->i_mutex);
 439         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
 440                                       lower_dir_dentry,
 441                                       encrypted_and_encoded_name_size);
 442         mutex_unlock(&d_inode(lower_dir_dentry)->i_mutex);
 443         if (IS_ERR(lower_dentry)) {
 444                 rc = PTR_ERR(lower_dentry);
 445                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 446                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
 447                                 encrypted_and_encoded_name);
 448                 goto out;
 449         }
 450 interpose:
 451         rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
 452                                        ecryptfs_dir_inode);
 453 out:
 454         kfree(encrypted_and_encoded_name);
 455         return ERR_PTR(rc);
 456 }
 457
 458 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 459                          struct dentry *new_dentry)
 460 {
 461         struct dentry *lower_old_dentry;
 462         struct dentry *lower_new_dentry;
 463         struct dentry *lower_dir_dentry;
 464         u64 file_size_save;
 465         int rc;
 466
 467         file_size_save = i_size_read(d_inode(old_dentry));
 468         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 469         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 470         dget(lower_old_dentry);
 471         dget(lower_new_dentry);
 472         lower_dir_dentry = lock_parent(lower_new_dentry);
 473         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 474                       lower_new_dentry, NULL);
 475         if (rc || d_really_is_negative(lower_new_dentry))
 476                 goto out_lock;
 477         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 478         if (rc)
 479                 goto out_lock;
 480         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 481         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 482         set_nlink(d_inode(old_dentry),
 483                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 484         i_size_write(d_inode(new_dentry), file_size_save);
 485 out_lock:
 486         unlock_dir(lower_dir_dentry);
 487         dput(lower_new_dentry);
 488         dput(lower_old_dentry);
 489         return rc;
 490 }
 491
 492 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 493 {
 494         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 495 }
 496
 497 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 498                             const char *symname)
 499 {
 500         int rc;
 501         struct dentry *lower_dentry;
 502         struct dentry *lower_dir_dentry;
 503         char *encoded_symname;
 504         size_t encoded_symlen;
 505         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 506
 507         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 508         dget(lower_dentry);
 509         lower_dir_dentry = lock_parent(lower_dentry);
 510         mount_crypt_stat = &ecryptfs_superblock_to_private(
 511                 dir->i_sb)->mount_crypt_stat;
 512         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 513                                                   &encoded_symlen,
 514                                                   NULL,
 515                                                   mount_crypt_stat, symname,
 516                                                   strlen(symname));
 517         if (rc)
 518                 goto out_lock;
 519         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 520                          encoded_symname);
 521         kfree(encoded_symname);
 522         if (rc || d_really_is_negative(lower_dentry))
 523                 goto out_lock;
 524         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 525         if (rc)
 526                 goto out_lock;
 527         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 528         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 529 out_lock:
 530         unlock_dir(lower_dir_dentry);
 531         dput(lower_dentry);
 532         if (d_really_is_negative(dentry))
 533                 d_drop(dentry);
 534         return rc;
 535 }
 536
 537 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 538 {
 539         int rc;
 540         struct dentry *lower_dentry;
 541         struct dentry *lower_dir_dentry;
 542
 543         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 544         lower_dir_dentry = lock_parent(lower_dentry);
 545         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 546         if (rc || d_really_is_negative(lower_dentry))
 547                 goto out;
 548         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 549         if (rc)
 550                 goto out;
 551         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 552         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 553         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 554 out:
 555         unlock_dir(lower_dir_dentry);
 556         if (d_really_is_negative(dentry))
 557                 d_drop(dentry);
 558         return rc;
 559 }
 560
 561 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 562 {
 563         struct dentry *lower_dentry;
 564         struct dentry *lower_dir_dentry;
 565         int rc;
 566
 567         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 568         dget(dentry);
 569         lower_dir_dentry = lock_parent(lower_dentry);
 570         dget(lower_dentry);
 571         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 572         dput(lower_dentry);
 573         if (!rc && d_really_is_positive(dentry))
 574                 clear_nlink(d_inode(dentry));
 575         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 576         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 577         unlock_dir(lower_dir_dentry);
 578         if (!rc)
 579                 d_drop(dentry);
 580         dput(dentry);
 581         return rc;
 582 }
 583
 584 static int
 585 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 586 {
 587         int rc;
 588         struct dentry *lower_dentry;
 589         struct dentry *lower_dir_dentry;
 590
 591         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 592         lower_dir_dentry = lock_parent(lower_dentry);
 593         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 594         if (rc || d_really_is_negative(lower_dentry))
 595                 goto out;
 596         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 597         if (rc)
 598                 goto out;
 599         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 600         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 601 out:
 602         unlock_dir(lower_dir_dentry);
 603         if (d_really_is_negative(dentry))
 604                 d_drop(dentry);
 605         return rc;
 606 }
 607
 608 static int
 609 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 610                 struct inode *new_dir, struct dentry *new_dentry)
 611 {
 612         int rc;
 613         struct dentry *lower_old_dentry;
 614         struct dentry *lower_new_dentry;
 615         struct dentry *lower_old_dir_dentry;
 616         struct dentry *lower_new_dir_dentry;
 617         struct dentry *trap = NULL;
 618         struct inode *target_inode;
 619
 620         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 621         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 622         dget(lower_old_dentry);
 623         dget(lower_new_dentry);
 624         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 625         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 626         target_inode = d_inode(new_dentry);
 627         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 628         /* source should not be ancestor of target */
 629         if (trap == lower_old_dentry) {
 630                 rc = -EINVAL;
 631                 goto out_lock;
 632         }
 633         /* target should not be ancestor of source */
 634         if (trap == lower_new_dentry) {
 635                 rc = -ENOTEMPTY;
 636                 goto out_lock;
 637         }
 638         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 639                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 640                         NULL, 0);
 641         if (rc)
 642                 goto out_lock;
 643         if (target_inode)
 644                 fsstack_copy_attr_all(target_inode,
 645                                       ecryptfs_inode_to_lower(target_inode));
 646         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 647         if (new_dir != old_dir)
 648                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 649 out_lock:
 650         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 651         dput(lower_new_dir_dentry);
 652         dput(lower_old_dir_dentry);
 653         dput(lower_new_dentry);
 654         dput(lower_old_dentry);
 655         return rc;
 656 }
 657
 658 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 659 {
 660         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 661         char *lower_buf;
 662         char *buf;
 663         mm_segment_t old_fs;
 664         int rc;
 665
 666         lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
 667         if (!lower_buf)
 668                 return ERR_PTR(-ENOMEM);
 669         old_fs = get_fs();
 670         set_fs(get_ds());
 671         rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
 672                                                    (char __user *)lower_buf,
 673                                                    PATH_MAX);
 674         set_fs(old_fs);
 675         if (rc < 0)
 676                 goto out;
 677         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 678                                                   lower_buf, rc);
 679 out:
 680         kfree(lower_buf);
 681         return rc ? ERR_PTR(rc) : buf;
 682 }
 683
 684 static const char *ecryptfs_follow_link(struct dentry *dentry, void **cookie)
 685 {
 686         size_t len;
 687         char *buf = ecryptfs_readlink_lower(dentry, &len);
 688         if (IS_ERR(buf))
 689                 return buf;
 690         fsstack_copy_attr_atime(d_inode(dentry),
 691                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 692         buf[len] = '\0';
 693         return *cookie = buf;
 694 }
 695
 696 /**
 697  * upper_size_to_lower_size
 698  * @crypt_stat: Crypt_stat associated with file
 699  * @upper_size: Size of the upper file
 700  *
 701  * Calculate the required size of the lower file based on the
 702  * specified size of the upper file. This calculation is based on the
 703  * number of headers in the underlying file and the extent size.
 704  *
 705  * Returns Calculated size of the lower file.
 706  */
 707 static loff_t
 708 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 709                          loff_t upper_size)
 710 {
 711         loff_t lower_size;
 712
 713         lower_size = ecryptfs_lower_header_size(crypt_stat);
 714         if (upper_size != 0) {
 715                 loff_t num_extents;
 716
 717                 num_extents = upper_size >> crypt_stat->extent_shift;
 718                 if (upper_size & ~crypt_stat->extent_mask)
 719                         num_extents++;
 720                 lower_size += (num_extents * crypt_stat->extent_size);
 721         }
 722         return lower_size;
 723 }
 724
 725 /**
 726  * truncate_upper
 727  * @dentry: The ecryptfs layer dentry
 728  * @ia: Address of the ecryptfs inode's attributes
 729  * @lower_ia: Address of the lower inode's attributes
 730  *
 731  * Function to handle truncations modifying the size of the file. Note
 732  * that the file sizes are interpolated. When expanding, we are simply
 733  * writing strings of 0's out. When truncating, we truncate the upper
 734  * inode and update the lower_ia according to the page index
 735  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 736  * the caller must use lower_ia in a call to notify_change() to perform
 737  * the truncation of the lower inode.
 738  *
 739  * Returns zero on success; non-zero otherwise
 740  */
 741 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 742                           struct iattr *lower_ia)
 743 {
 744         int rc = 0;
 745         struct inode *inode = d_inode(dentry);
 746         struct ecryptfs_crypt_stat *crypt_stat;
 747         loff_t i_size = i_size_read(inode);
 748         loff_t lower_size_before_truncate;
 749         loff_t lower_size_after_truncate;
 750
 751         if (unlikely((ia->ia_size == i_size))) {
 752                 lower_ia->ia_valid &= ~ATTR_SIZE;
 753                 return 0;
 754         }
 755         rc = ecryptfs_get_lower_file(dentry, inode);
 756         if (rc)
 757                 return rc;
 758         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 759         /* Switch on growing or shrinking file */
 760         if (ia->ia_size > i_size) {
 761                 char zero[] = { 0x00 };
 762
 763                 lower_ia->ia_valid &= ~ATTR_SIZE;
 764                 /* Write a single 0 at the last position of the file;
 765                  * this triggers code that will fill in 0's throughout
 766                  * the intermediate portion of the previous end of the
 767                  * file and the new and of the file */
 768                 rc = ecryptfs_write(inode, zero,
 769                                     (ia->ia_size - 1), 1);
 770         } else { /* ia->ia_size < i_size_read(inode) */
 771                 /* We're chopping off all the pages down to the page
 772                  * in which ia->ia_size is located. Fill in the end of
 773                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
 774                  * PAGE_CACHE_SIZE with zeros. */
 775                 size_t num_zeros = (PAGE_CACHE_SIZE
 776                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
 777
 778                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 779                         truncate_setsize(inode, ia->ia_size);
 780                         lower_ia->ia_size = ia->ia_size;
 781                         lower_ia->ia_valid |= ATTR_SIZE;
 782                         goto out;
 783                 }
 784                 if (num_zeros) {
 785                         char *zeros_virt;
 786
 787                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 788                         if (!zeros_virt) {
 789                                 rc = -ENOMEM;
 790                                 goto out;
 791                         }
 792                         rc = ecryptfs_write(inode, zeros_virt,
 793                                             ia->ia_size, num_zeros);
 794                         kfree(zeros_virt);
 795                         if (rc) {
 796                                 printk(KERN_ERR "Error attempting to zero out "
 797                                        "the remainder of the end page on "
 798                                        "reducing truncate; rc = [%d]\n", rc);
 799                                 goto out;
 800                         }
 801                 }
 802                 truncate_setsize(inode, ia->ia_size);
 803                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 804                 if (rc) {
 805                         printk(KERN_ERR "Problem with "
 806                                "ecryptfs_write_inode_size_to_metadata; "
 807                                "rc = [%d]\n", rc);
 808                         goto out;
 809                 }
 810                 /* We are reducing the size of the ecryptfs file, and need to
 811                  * know if we need to reduce the size of the lower file. */
 812                 lower_size_before_truncate =
 813                     upper_size_to_lower_size(crypt_stat, i_size);
 814                 lower_size_after_truncate =
 815                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 816                 if (lower_size_after_truncate < lower_size_before_truncate) {
 817                         lower_ia->ia_size = lower_size_after_truncate;
 818                         lower_ia->ia_valid |= ATTR_SIZE;
 819                 } else
 820                         lower_ia->ia_valid &= ~ATTR_SIZE;
 821         }
 822 out:
 823         ecryptfs_put_lower_file(inode);
 824         return rc;
 825 }
 826
 827 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 828 {
 829         struct ecryptfs_crypt_stat *crypt_stat;
 830         loff_t lower_oldsize, lower_newsize;
 831
 832         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 833         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 834                                                  i_size_read(inode));
 835         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 836         if (lower_newsize > lower_oldsize) {
 837                 /*
 838                  * The eCryptfs inode and the new *lower* size are mixed here
 839                  * because we may not have the lower i_mutex held and/or it may
 840                  * not be appropriate to call inode_newsize_ok() with inodes
 841                  * from other filesystems.
 842                  */
 843                 return inode_newsize_ok(inode, lower_newsize);
 844         }
 845
 846         return 0;
 847 }
 848
 849 /**
 850  * ecryptfs_truncate
 851  * @dentry: The ecryptfs layer dentry
 852  * @new_length: The length to expand the file to
 853  *
 854  * Simple function that handles the truncation of an eCryptfs inode and
 855  * its corresponding lower inode.
 856  *
 857  * Returns zero on success; non-zero otherwise
 858  */
 859 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 860 {
 861         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 862         struct iattr lower_ia = { .ia_valid = 0 };
 863         int rc;
 864
 865         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 866         if (rc)
 867                 return rc;
 868
 869         rc = truncate_upper(dentry, &ia, &lower_ia);
 870         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 871                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 872
 873                 mutex_lock(&d_inode(lower_dentry)->i_mutex);
 874                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 875                 mutex_unlock(&d_inode(lower_dentry)->i_mutex);
 876         }
 877         return rc;
 878 }
 879
 880 static int
 881 ecryptfs_permission(struct inode *inode, int mask)
 882 {
 883         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 884 }
 885
 886 /**
 887  * ecryptfs_setattr
 888  * @dentry: dentry handle to the inode to modify
 889  * @ia: Structure with flags of what to change and values
 890  *
 891  * Updates the metadata of an inode. If the update is to the size
 892  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 893  * of both the ecryptfs inode and the lower inode.
 894  *
 895  * All other metadata changes will be passed right to the lower filesystem,
 896  * and we will just update our inode to look like the lower.
 897  */
 898 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 899 {
 900         int rc = 0;
 901         struct dentry *lower_dentry;
 902         struct iattr lower_ia;
 903         struct inode *inode;
 904         struct inode *lower_inode;
 905         struct ecryptfs_crypt_stat *crypt_stat;
 906
 907         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 908         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 909                 ecryptfs_init_crypt_stat(crypt_stat);
 910         inode = d_inode(dentry);
 911         lower_inode = ecryptfs_inode_to_lower(inode);
 912         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 913         mutex_lock(&crypt_stat->cs_mutex);
 914         if (d_is_dir(dentry))
 915                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 916         else if (d_is_reg(dentry)
 917                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 918                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 919                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 920
 921                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 922                         dentry->d_sb)->mount_crypt_stat;
 923                 rc = ecryptfs_get_lower_file(dentry, inode);
 924                 if (rc) {
 925                         mutex_unlock(&crypt_stat->cs_mutex);
 926                         goto out;
 927                 }
 928                 rc = ecryptfs_read_metadata(dentry);
 929                 ecryptfs_put_lower_file(inode);
 930                 if (rc) {
 931                         if (!(mount_crypt_stat->flags
 932                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 933                                 rc = -EIO;
 934                                 printk(KERN_WARNING "Either the lower file "
 935                                        "is not in a valid eCryptfs format, "
 936                                        "or the key could not be retrieved. "
 937                                        "Plaintext passthrough mode is not "
 938                                        "enabled; returning -EIO\n");
 939                                 mutex_unlock(&crypt_stat->cs_mutex);
 940                                 goto out;
 941                         }
 942                         rc = 0;
 943                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 944                                                | ECRYPTFS_ENCRYPTED);
 945                 }
 946         }
 947         mutex_unlock(&crypt_stat->cs_mutex);
 948
 949         rc = inode_change_ok(inode, ia);
 950         if (rc)
 951                 goto out;
 952         if (ia->ia_valid & ATTR_SIZE) {
 953                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 954                 if (rc)
 955                         goto out;
 956         }
 957
 958         memcpy(&lower_ia, ia, sizeof(lower_ia));
 959         if (ia->ia_valid & ATTR_FILE)
 960                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 961         if (ia->ia_valid & ATTR_SIZE) {
 962                 rc = truncate_upper(dentry, ia, &lower_ia);
 963                 if (rc < 0)
 964                         goto out;
 965         }
 966
 967         /*
 968          * mode change is for clearing setuid/setgid bits. Allow lower fs
 969          * to interpret this in its own way.
 970          */
 971         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 972                 lower_ia.ia_valid &= ~ATTR_MODE;
 973
 974         mutex_lock(&d_inode(lower_dentry)->i_mutex);
 975         rc = notify_change(lower_dentry, &lower_ia, NULL);
 976         mutex_unlock(&d_inode(lower_dentry)->i_mutex);
 977 out:
 978         fsstack_copy_attr_all(inode, lower_inode);
 979         return rc;
 980 }
 981
 982 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
 983                                  struct kstat *stat)
 984 {
 985         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 986         int rc = 0;
 987
 988         mount_crypt_stat = &ecryptfs_superblock_to_private(
 989                                                 dentry->d_sb)->mount_crypt_stat;
 990         generic_fillattr(d_inode(dentry), stat);
 991         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 992                 char *target;
 993                 size_t targetsiz;
 994
 995                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 996                 if (!IS_ERR(target)) {
 997                         kfree(target);
 998                         stat->size = targetsiz;
 999                 } else {
1000                         rc = PTR_ERR(target);
1001                 }
1002         }
1003         return rc;
1004 }
1005
1006 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1007                             struct kstat *stat)
1008 {
1009         struct kstat lower_stat;
1010         int rc;
1011
1012         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
1013         if (!rc) {
1014                 fsstack_copy_attr_all(d_inode(dentry),
1015                                       ecryptfs_inode_to_lower(d_inode(dentry)));
1016                 generic_fillattr(d_inode(dentry), stat);
1017                 stat->blocks = lower_stat.blocks;
1018         }
1019         return rc;
1020 }
1021
1022 int
1023 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1024                   size_t size, int flags)
1025 {
1026         int rc = 0;
1027         struct dentry *lower_dentry;
1028
1029         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1030         if (!d_inode(lower_dentry)->i_op->setxattr) {
1031                 rc = -EOPNOTSUPP;
1032                 goto out;
1033         }
1034
1035         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1036         if (!rc && d_really_is_positive(dentry))
1037                 fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry));
1038 out:
1039         return rc;
1040 }
1041
1042 ssize_t
1043 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1044                         void *value, size_t size)
1045 {
1046         int rc = 0;
1047
1048         if (!d_inode(lower_dentry)->i_op->getxattr) {
1049                 rc = -EOPNOTSUPP;
1050                 goto out;
1051         }
1052         mutex_lock(&d_inode(lower_dentry)->i_mutex);
1053         rc = d_inode(lower_dentry)->i_op->getxattr(lower_dentry, name, value,
1054                                                    size);
1055         mutex_unlock(&d_inode(lower_dentry)->i_mutex);
1056 out:
1057         return rc;
1058 }
1059
1060 static ssize_t
1061 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1062                   size_t size)
1063 {
1064         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1065                                        value, size);
1066 }
1067
1068 static ssize_t
1069 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1070 {
1071         int rc = 0;
1072         struct dentry *lower_dentry;
1073
1074         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1075         if (!d_inode(lower_dentry)->i_op->listxattr) {
1076                 rc = -EOPNOTSUPP;
1077                 goto out;
1078         }
1079         mutex_lock(&d_inode(lower_dentry)->i_mutex);
1080         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1081         mutex_unlock(&d_inode(lower_dentry)->i_mutex);
1082 out:
1083         return rc;
1084 }
1085
1086 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1087 {
1088         int rc = 0;
1089         struct dentry *lower_dentry;
1090
1091         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1092         if (!d_inode(lower_dentry)->i_op->removexattr) {
1093                 rc = -EOPNOTSUPP;
1094                 goto out;
1095         }
1096         mutex_lock(&d_inode(lower_dentry)->i_mutex);
1097         rc = d_inode(lower_dentry)->i_op->removexattr(lower_dentry, name);
1098         mutex_unlock(&d_inode(lower_dentry)->i_mutex);
1099 out:
1100         return rc;
1101 }
1102
1103 const struct inode_operations ecryptfs_symlink_iops = {
1104         .readlink = generic_readlink,
1105         .follow_link = ecryptfs_follow_link,
1106         .put_link = kfree_put_link,
1107         .permission = ecryptfs_permission,
1108         .setattr = ecryptfs_setattr,
1109         .getattr = ecryptfs_getattr_link,
1110         .setxattr = ecryptfs_setxattr,
1111         .getxattr = ecryptfs_getxattr,
1112         .listxattr = ecryptfs_listxattr,
1113         .removexattr = ecryptfs_removexattr
1114 };
1115
1116 const struct inode_operations ecryptfs_dir_iops = {
1117         .create = ecryptfs_create,
1118         .lookup = ecryptfs_lookup,
1119         .link = ecryptfs_link,
1120         .unlink = ecryptfs_unlink,
1121         .symlink = ecryptfs_symlink,
1122         .mkdir = ecryptfs_mkdir,
1123         .rmdir = ecryptfs_rmdir,
1124         .mknod = ecryptfs_mknod,
1125         .rename = ecryptfs_rename,
1126         .permission = ecryptfs_permission,
1127         .setattr = ecryptfs_setattr,
1128         .setxattr = ecryptfs_setxattr,
1129         .getxattr = ecryptfs_getxattr,
1130         .listxattr = ecryptfs_listxattr,
1131         .removexattr = ecryptfs_removexattr
1132 };
1133
1134 const struct inode_operations ecryptfs_main_iops = {
1135         .permission = ecryptfs_permission,
1136         .setattr = ecryptfs_setattr,
1137         .getattr = ecryptfs_getattr,
1138         .setxattr = ecryptfs_setxattr,
1139         .getxattr = ecryptfs_getxattr,
1140         .listxattr = ecryptfs_listxattr,
1141         .removexattr = ecryptfs_removexattr
1142 };