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/fs_stack.h>
  33 #include <linux/slab.h>
  34 #include <linux/xattr.h>
  35 #include <asm/unaligned.h>
  36 #include "ecryptfs_kernel.h"
  37
  38 static struct dentry *lock_parent(struct dentry *dentry)
  39 {
  40         struct dentry *dir;
  41
  42         dir = dget_parent(dentry);
  43         inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
  44         return dir;
  45 }
  46
  47 static void unlock_dir(struct dentry *dir)
  48 {
  49         inode_unlock(d_inode(dir));
  50         dput(dir);
  51 }
  52
  53 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
  54 {
  55         return ecryptfs_inode_to_lower(inode) == lower_inode;
  56 }
  57
  58 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
  59 {
  60         struct inode *lower_inode = opaque;
  61
  62         ecryptfs_set_inode_lower(inode, lower_inode);
  63         fsstack_copy_attr_all(inode, lower_inode);
  64         /* i_size will be overwritten for encrypted regular files */
  65         fsstack_copy_inode_size(inode, lower_inode);
  66         inode->i_ino = lower_inode->i_ino;
  67         inode->i_version++;
  68         inode->i_mapping->a_ops = &ecryptfs_aops;
  69
  70         if (S_ISLNK(inode->i_mode))
  71                 inode->i_op = &ecryptfs_symlink_iops;
  72         else if (S_ISDIR(inode->i_mode))
  73                 inode->i_op = &ecryptfs_dir_iops;
  74         else
  75                 inode->i_op = &ecryptfs_main_iops;
  76
  77         if (S_ISDIR(inode->i_mode))
  78                 inode->i_fop = &ecryptfs_dir_fops;
  79         else if (special_file(inode->i_mode))
  80                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
  81         else
  82                 inode->i_fop = &ecryptfs_main_fops;
  83
  84         return 0;
  85 }
  86
  87 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  88                                           struct super_block *sb)
  89 {
  90         struct inode *inode;
  91
  92         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  93                 return ERR_PTR(-EXDEV);
  94         if (!igrab(lower_inode))
  95                 return ERR_PTR(-ESTALE);
  96         inode = iget5_locked(sb, (unsigned long)lower_inode,
  97                              ecryptfs_inode_test, ecryptfs_inode_set,
  98                              lower_inode);
  99         if (!inode) {
 100                 iput(lower_inode);
 101                 return ERR_PTR(-EACCES);
 102         }
 103         if (!(inode->i_state & I_NEW))
 104                 iput(lower_inode);
 105
 106         return inode;
 107 }
 108
 109 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 110                                  struct super_block *sb)
 111 {
 112         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 113
 114         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 115                 unlock_new_inode(inode);
 116
 117         return inode;
 118 }
 119
 120 /**
 121  * ecryptfs_interpose
 122  * @lower_dentry: Existing dentry in the lower filesystem
 123  * @dentry: ecryptfs' dentry
 124  * @sb: ecryptfs's super_block
 125  *
 126  * Interposes upper and lower dentries.
 127  *
 128  * Returns zero on success; non-zero otherwise
 129  */
 130 static int ecryptfs_interpose(struct dentry *lower_dentry,
 131                               struct dentry *dentry, struct super_block *sb)
 132 {
 133         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 134
 135         if (IS_ERR(inode))
 136                 return PTR_ERR(inode);
 137         d_instantiate(dentry, inode);
 138
 139         return 0;
 140 }
 141
 142 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 143                               struct inode *inode)
 144 {
 145         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 146         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 147         struct dentry *lower_dir_dentry;
 148         int rc;
 149
 150         dget(lower_dentry);
 151         lower_dir_dentry = lock_parent(lower_dentry);
 152         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 153         if (rc) {
 154                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 155                 goto out_unlock;
 156         }
 157         fsstack_copy_attr_times(dir, lower_dir_inode);
 158         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 159         inode->i_ctime = dir->i_ctime;
 160         d_drop(dentry);
 161 out_unlock:
 162         unlock_dir(lower_dir_dentry);
 163         dput(lower_dentry);
 164         return rc;
 165 }
 166
 167 /**
 168  * ecryptfs_do_create
 169  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 170  * @ecryptfs_dentry: New file's dentry in ecryptfs
 171  * @mode: The mode of the new file
 172  *
 173  * Creates the underlying file and the eCryptfs inode which will link to
 174  * it. It will also update the eCryptfs directory inode to mimic the
 175  * stat of the lower directory inode.
 176  *
 177  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 178  */
 179 static struct inode *
 180 ecryptfs_do_create(struct inode *directory_inode,
 181                    struct dentry *ecryptfs_dentry, umode_t mode)
 182 {
 183         int rc;
 184         struct dentry *lower_dentry;
 185         struct dentry *lower_dir_dentry;
 186         struct inode *inode;
 187
 188         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 189         lower_dir_dentry = lock_parent(lower_dentry);
 190         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 191         if (rc) {
 192                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 193                        "rc = [%d]\n", __func__, rc);
 194                 inode = ERR_PTR(rc);
 195                 goto out_lock;
 196         }
 197         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 198                                      directory_inode->i_sb);
 199         if (IS_ERR(inode)) {
 200                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 201                 goto out_lock;
 202         }
 203         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 204         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 205 out_lock:
 206         unlock_dir(lower_dir_dentry);
 207         return inode;
 208 }
 209
 210 /**
 211  * ecryptfs_initialize_file
 212  *
 213  * Cause the file to be changed from a basic empty file to an ecryptfs
 214  * file with a header and first data page.
 215  *
 216  * Returns zero on success
 217  */
 218 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 219                              struct inode *ecryptfs_inode)
 220 {
 221         struct ecryptfs_crypt_stat *crypt_stat =
 222                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 223         int rc = 0;
 224
 225         if (S_ISDIR(ecryptfs_inode->i_mode)) {
 226                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 227                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 228                 goto out;
 229         }
 230         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 231         rc = ecryptfs_new_file_context(ecryptfs_inode);
 232         if (rc) {
 233                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 234                                 "context; rc = [%d]\n", rc);
 235                 goto out;
 236         }
 237         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 238         if (rc) {
 239                 printk(KERN_ERR "%s: Error attempting to initialize "
 240                         "the lower file for the dentry with name "
 241                         "[%pd]; rc = [%d]\n", __func__,
 242                         ecryptfs_dentry, rc);
 243                 goto out;
 244         }
 245         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 246         if (rc)
 247                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 248         ecryptfs_put_lower_file(ecryptfs_inode);
 249 out:
 250         return rc;
 251 }
 252
 253 /**
 254  * ecryptfs_create
 255  * @dir: The inode of the directory in which to create the file.
 256  * @dentry: The eCryptfs dentry
 257  * @mode: The mode of the new file.
 258  *
 259  * Creates a new file.
 260  *
 261  * Returns zero on success; non-zero on error condition
 262  */
 263 static int
 264 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 265                 umode_t mode, bool excl)
 266 {
 267         struct inode *ecryptfs_inode;
 268         int rc;
 269
 270         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 271                                             mode);
 272         if (IS_ERR(ecryptfs_inode)) {
 273                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 274                                 "lower filesystem\n");
 275                 rc = PTR_ERR(ecryptfs_inode);
 276                 goto out;
 277         }
 278         /* At this point, a file exists on "disk"; we need to make sure
 279          * that this on disk file is prepared to be an ecryptfs file */
 280         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 281         if (rc) {
 282                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 283                                    ecryptfs_inode);
 284                 iget_failed(ecryptfs_inode);
 285                 goto out;
 286         }
 287         unlock_new_inode(ecryptfs_inode);
 288         d_instantiate(ecryptfs_dentry, ecryptfs_inode);
 289 out:
 290         return rc;
 291 }
 292
 293 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 294 {
 295         struct ecryptfs_crypt_stat *crypt_stat;
 296         int rc;
 297
 298         rc = ecryptfs_get_lower_file(dentry, inode);
 299         if (rc) {
 300                 printk(KERN_ERR "%s: Error attempting to initialize "
 301                         "the lower file for the dentry with name "
 302                         "[%pd]; rc = [%d]\n", __func__,
 303                         dentry, rc);
 304                 return rc;
 305         }
 306
 307         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 308         /* TODO: lock for crypt_stat comparison */
 309         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 310                 ecryptfs_set_default_sizes(crypt_stat);
 311
 312         rc = ecryptfs_read_and_validate_header_region(inode);
 313         ecryptfs_put_lower_file(inode);
 314         if (rc) {
 315                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
 316                 if (!rc)
 317                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 318         }
 319
 320         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
 321         return 0;
 322 }
 323
 324 /**
 325  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 326  */
 327 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
 328                                      struct dentry *lower_dentry)
 329 {
 330         struct inode *inode, *lower_inode = d_inode(lower_dentry);
 331         struct ecryptfs_dentry_info *dentry_info;
 332         struct vfsmount *lower_mnt;
 333         int rc = 0;
 334
 335         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 336         if (!dentry_info) {
 337                 dput(lower_dentry);
 338                 return ERR_PTR(-ENOMEM);
 339         }
 340
 341         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 342         fsstack_copy_attr_atime(d_inode(dentry->d_parent),
 343                                 d_inode(lower_dentry->d_parent));
 344         BUG_ON(!d_count(lower_dentry));
 345
 346         ecryptfs_set_dentry_private(dentry, dentry_info);
 347         dentry_info->lower_path.mnt = lower_mnt;
 348         dentry_info->lower_path.dentry = lower_dentry;
 349
 350         if (d_really_is_negative(lower_dentry)) {
 351                 /* We want to add because we couldn't find in lower */
 352                 d_add(dentry, NULL);
 353                 return NULL;
 354         }
 355         inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
 356         if (IS_ERR(inode)) {
 357                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 358                        __func__, PTR_ERR(inode));
 359                 return ERR_CAST(inode);
 360         }
 361         if (S_ISREG(inode->i_mode)) {
 362                 rc = ecryptfs_i_size_read(dentry, inode);
 363                 if (rc) {
 364                         make_bad_inode(inode);
 365                         return ERR_PTR(rc);
 366                 }
 367         }
 368
 369         if (inode->i_state & I_NEW)
 370                 unlock_new_inode(inode);
 371         return d_splice_alias(inode, dentry);
 372 }
 373
 374 /**
 375  * ecryptfs_lookup
 376  * @ecryptfs_dir_inode: The eCryptfs directory inode
 377  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 378  * @flags: lookup flags
 379  *
 380  * Find a file on disk. If the file does not exist, then we'll add it to the
 381  * dentry cache and continue on to read it from the disk.
 382  */
 383 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 384                                       struct dentry *ecryptfs_dentry,
 385                                       unsigned int flags)
 386 {
 387         char *encrypted_and_encoded_name = NULL;
 388         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 389         struct dentry *lower_dir_dentry, *lower_dentry;
 390         const char *name = ecryptfs_dentry->d_name.name;
 391         size_t len = ecryptfs_dentry->d_name.len;
 392         struct dentry *res;
 393         int rc = 0;
 394
 395         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 396
 397         mount_crypt_stat = &ecryptfs_superblock_to_private(
 398                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 399         if (mount_crypt_stat
 400             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
 401                 rc = ecryptfs_encrypt_and_encode_filename(
 402                         &encrypted_and_encoded_name, &len,
 403                         mount_crypt_stat, name, len);
 404                 if (rc) {
 405                         printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 406                                "filename; rc = [%d]\n", __func__, rc);
 407                         return ERR_PTR(rc);
 408                 }
 409                 name = encrypted_and_encoded_name;
 410         }
 411
 412         lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
 413         if (IS_ERR(lower_dentry)) {
 414                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 415                                 "[%ld] on lower_dentry = [%s]\n", __func__,
 416                                 PTR_ERR(lower_dentry),
 417                                 name);
 418                 res = ERR_CAST(lower_dentry);
 419         } else {
 420                 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
 421         }
 422         kfree(encrypted_and_encoded_name);
 423         return res;
 424 }
 425
 426 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 427                          struct dentry *new_dentry)
 428 {
 429         struct dentry *lower_old_dentry;
 430         struct dentry *lower_new_dentry;
 431         struct dentry *lower_dir_dentry;
 432         u64 file_size_save;
 433         int rc;
 434
 435         file_size_save = i_size_read(d_inode(old_dentry));
 436         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 437         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 438         dget(lower_old_dentry);
 439         dget(lower_new_dentry);
 440         lower_dir_dentry = lock_parent(lower_new_dentry);
 441         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 442                       lower_new_dentry, NULL);
 443         if (rc || d_really_is_negative(lower_new_dentry))
 444                 goto out_lock;
 445         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 446         if (rc)
 447                 goto out_lock;
 448         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 449         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 450         set_nlink(d_inode(old_dentry),
 451                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 452         i_size_write(d_inode(new_dentry), file_size_save);
 453 out_lock:
 454         unlock_dir(lower_dir_dentry);
 455         dput(lower_new_dentry);
 456         dput(lower_old_dentry);
 457         return rc;
 458 }
 459
 460 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 461 {
 462         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 463 }
 464
 465 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 466                             const char *symname)
 467 {
 468         int rc;
 469         struct dentry *lower_dentry;
 470         struct dentry *lower_dir_dentry;
 471         char *encoded_symname;
 472         size_t encoded_symlen;
 473         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 474
 475         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 476         dget(lower_dentry);
 477         lower_dir_dentry = lock_parent(lower_dentry);
 478         mount_crypt_stat = &ecryptfs_superblock_to_private(
 479                 dir->i_sb)->mount_crypt_stat;
 480         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 481                                                   &encoded_symlen,
 482                                                   mount_crypt_stat, symname,
 483                                                   strlen(symname));
 484         if (rc)
 485                 goto out_lock;
 486         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 487                          encoded_symname);
 488         kfree(encoded_symname);
 489         if (rc || d_really_is_negative(lower_dentry))
 490                 goto out_lock;
 491         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 492         if (rc)
 493                 goto out_lock;
 494         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 495         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 496 out_lock:
 497         unlock_dir(lower_dir_dentry);
 498         dput(lower_dentry);
 499         if (d_really_is_negative(dentry))
 500                 d_drop(dentry);
 501         return rc;
 502 }
 503
 504 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 505 {
 506         int rc;
 507         struct dentry *lower_dentry;
 508         struct dentry *lower_dir_dentry;
 509
 510         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 511         lower_dir_dentry = lock_parent(lower_dentry);
 512         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 513         if (rc || d_really_is_negative(lower_dentry))
 514                 goto out;
 515         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 516         if (rc)
 517                 goto out;
 518         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 519         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 520         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 521 out:
 522         unlock_dir(lower_dir_dentry);
 523         if (d_really_is_negative(dentry))
 524                 d_drop(dentry);
 525         return rc;
 526 }
 527
 528 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 529 {
 530         struct dentry *lower_dentry;
 531         struct dentry *lower_dir_dentry;
 532         int rc;
 533
 534         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 535         dget(dentry);
 536         lower_dir_dentry = lock_parent(lower_dentry);
 537         dget(lower_dentry);
 538         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 539         dput(lower_dentry);
 540         if (!rc && d_really_is_positive(dentry))
 541                 clear_nlink(d_inode(dentry));
 542         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 543         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 544         unlock_dir(lower_dir_dentry);
 545         if (!rc)
 546                 d_drop(dentry);
 547         dput(dentry);
 548         return rc;
 549 }
 550
 551 static int
 552 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 553 {
 554         int rc;
 555         struct dentry *lower_dentry;
 556         struct dentry *lower_dir_dentry;
 557
 558         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 559         lower_dir_dentry = lock_parent(lower_dentry);
 560         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 561         if (rc || d_really_is_negative(lower_dentry))
 562                 goto out;
 563         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 564         if (rc)
 565                 goto out;
 566         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 567         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 568 out:
 569         unlock_dir(lower_dir_dentry);
 570         if (d_really_is_negative(dentry))
 571                 d_drop(dentry);
 572         return rc;
 573 }
 574
 575 static int
 576 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 577                 struct inode *new_dir, struct dentry *new_dentry,
 578                 unsigned int flags)
 579 {
 580         int rc;
 581         struct dentry *lower_old_dentry;
 582         struct dentry *lower_new_dentry;
 583         struct dentry *lower_old_dir_dentry;
 584         struct dentry *lower_new_dir_dentry;
 585         struct dentry *trap = NULL;
 586         struct inode *target_inode;
 587
 588         if (flags)
 589                 return -EINVAL;
 590
 591         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 592         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 593         dget(lower_old_dentry);
 594         dget(lower_new_dentry);
 595         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 596         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 597         target_inode = d_inode(new_dentry);
 598         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 599         /* source should not be ancestor of target */
 600         if (trap == lower_old_dentry) {
 601                 rc = -EINVAL;
 602                 goto out_lock;
 603         }
 604         /* target should not be ancestor of source */
 605         if (trap == lower_new_dentry) {
 606                 rc = -ENOTEMPTY;
 607                 goto out_lock;
 608         }
 609         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 610                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 611                         NULL, 0);
 612         if (rc)
 613                 goto out_lock;
 614         if (target_inode)
 615                 fsstack_copy_attr_all(target_inode,
 616                                       ecryptfs_inode_to_lower(target_inode));
 617         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 618         if (new_dir != old_dir)
 619                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 620 out_lock:
 621         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 622         dput(lower_new_dir_dentry);
 623         dput(lower_old_dir_dentry);
 624         dput(lower_new_dentry);
 625         dput(lower_old_dentry);
 626         return rc;
 627 }
 628
 629 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 630 {
 631         DEFINE_DELAYED_CALL(done);
 632         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 633         const char *link;
 634         char *buf;
 635         int rc;
 636
 637         link = vfs_get_link(lower_dentry, &done);
 638         if (IS_ERR(link))
 639                 return ERR_CAST(link);
 640
 641         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 642                                                   link, strlen(link));
 643         do_delayed_call(&done);
 644         if (rc)
 645                 return ERR_PTR(rc);
 646
 647         return buf;
 648 }
 649
 650 static const char *ecryptfs_get_link(struct dentry *dentry,
 651                                      struct inode *inode,
 652                                      struct delayed_call *done)
 653 {
 654         size_t len;
 655         char *buf;
 656
 657         if (!dentry)
 658                 return ERR_PTR(-ECHILD);
 659
 660         buf = ecryptfs_readlink_lower(dentry, &len);
 661         if (IS_ERR(buf))
 662                 return buf;
 663         fsstack_copy_attr_atime(d_inode(dentry),
 664                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 665         buf[len] = '\0';
 666         set_delayed_call(done, kfree_link, buf);
 667         return buf;
 668 }
 669
 670 /**
 671  * upper_size_to_lower_size
 672  * @crypt_stat: Crypt_stat associated with file
 673  * @upper_size: Size of the upper file
 674  *
 675  * Calculate the required size of the lower file based on the
 676  * specified size of the upper file. This calculation is based on the
 677  * number of headers in the underlying file and the extent size.
 678  *
 679  * Returns Calculated size of the lower file.
 680  */
 681 static loff_t
 682 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 683                          loff_t upper_size)
 684 {
 685         loff_t lower_size;
 686
 687         lower_size = ecryptfs_lower_header_size(crypt_stat);
 688         if (upper_size != 0) {
 689                 loff_t num_extents;
 690
 691                 num_extents = upper_size >> crypt_stat->extent_shift;
 692                 if (upper_size & ~crypt_stat->extent_mask)
 693                         num_extents++;
 694                 lower_size += (num_extents * crypt_stat->extent_size);
 695         }
 696         return lower_size;
 697 }
 698
 699 /**
 700  * truncate_upper
 701  * @dentry: The ecryptfs layer dentry
 702  * @ia: Address of the ecryptfs inode's attributes
 703  * @lower_ia: Address of the lower inode's attributes
 704  *
 705  * Function to handle truncations modifying the size of the file. Note
 706  * that the file sizes are interpolated. When expanding, we are simply
 707  * writing strings of 0's out. When truncating, we truncate the upper
 708  * inode and update the lower_ia according to the page index
 709  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 710  * the caller must use lower_ia in a call to notify_change() to perform
 711  * the truncation of the lower inode.
 712  *
 713  * Returns zero on success; non-zero otherwise
 714  */
 715 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 716                           struct iattr *lower_ia)
 717 {
 718         int rc = 0;
 719         struct inode *inode = d_inode(dentry);
 720         struct ecryptfs_crypt_stat *crypt_stat;
 721         loff_t i_size = i_size_read(inode);
 722         loff_t lower_size_before_truncate;
 723         loff_t lower_size_after_truncate;
 724
 725         if (unlikely((ia->ia_size == i_size))) {
 726                 lower_ia->ia_valid &= ~ATTR_SIZE;
 727                 return 0;
 728         }
 729         rc = ecryptfs_get_lower_file(dentry, inode);
 730         if (rc)
 731                 return rc;
 732         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 733         /* Switch on growing or shrinking file */
 734         if (ia->ia_size > i_size) {
 735                 char zero[] = { 0x00 };
 736
 737                 lower_ia->ia_valid &= ~ATTR_SIZE;
 738                 /* Write a single 0 at the last position of the file;
 739                  * this triggers code that will fill in 0's throughout
 740                  * the intermediate portion of the previous end of the
 741                  * file and the new and of the file */
 742                 rc = ecryptfs_write(inode, zero,
 743                                     (ia->ia_size - 1), 1);
 744         } else { /* ia->ia_size < i_size_read(inode) */
 745                 /* We're chopping off all the pages down to the page
 746                  * in which ia->ia_size is located. Fill in the end of
 747                  * that page from (ia->ia_size & ~PAGE_MASK) to
 748                  * PAGE_SIZE with zeros. */
 749                 size_t num_zeros = (PAGE_SIZE
 750                                     - (ia->ia_size & ~PAGE_MASK));
 751
 752                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 753                         truncate_setsize(inode, ia->ia_size);
 754                         lower_ia->ia_size = ia->ia_size;
 755                         lower_ia->ia_valid |= ATTR_SIZE;
 756                         goto out;
 757                 }
 758                 if (num_zeros) {
 759                         char *zeros_virt;
 760
 761                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 762                         if (!zeros_virt) {
 763                                 rc = -ENOMEM;
 764                                 goto out;
 765                         }
 766                         rc = ecryptfs_write(inode, zeros_virt,
 767                                             ia->ia_size, num_zeros);
 768                         kfree(zeros_virt);
 769                         if (rc) {
 770                                 printk(KERN_ERR "Error attempting to zero out "
 771                                        "the remainder of the end page on "
 772                                        "reducing truncate; rc = [%d]\n", rc);
 773                                 goto out;
 774                         }
 775                 }
 776                 truncate_setsize(inode, ia->ia_size);
 777                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 778                 if (rc) {
 779                         printk(KERN_ERR "Problem with "
 780                                "ecryptfs_write_inode_size_to_metadata; "
 781                                "rc = [%d]\n", rc);
 782                         goto out;
 783                 }
 784                 /* We are reducing the size of the ecryptfs file, and need to
 785                  * know if we need to reduce the size of the lower file. */
 786                 lower_size_before_truncate =
 787                     upper_size_to_lower_size(crypt_stat, i_size);
 788                 lower_size_after_truncate =
 789                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 790                 if (lower_size_after_truncate < lower_size_before_truncate) {
 791                         lower_ia->ia_size = lower_size_after_truncate;
 792                         lower_ia->ia_valid |= ATTR_SIZE;
 793                 } else
 794                         lower_ia->ia_valid &= ~ATTR_SIZE;
 795         }
 796 out:
 797         ecryptfs_put_lower_file(inode);
 798         return rc;
 799 }
 800
 801 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 802 {
 803         struct ecryptfs_crypt_stat *crypt_stat;
 804         loff_t lower_oldsize, lower_newsize;
 805
 806         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 807         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 808                                                  i_size_read(inode));
 809         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 810         if (lower_newsize > lower_oldsize) {
 811                 /*
 812                  * The eCryptfs inode and the new *lower* size are mixed here
 813                  * because we may not have the lower i_mutex held and/or it may
 814                  * not be appropriate to call inode_newsize_ok() with inodes
 815                  * from other filesystems.
 816                  */
 817                 return inode_newsize_ok(inode, lower_newsize);
 818         }
 819
 820         return 0;
 821 }
 822
 823 /**
 824  * ecryptfs_truncate
 825  * @dentry: The ecryptfs layer dentry
 826  * @new_length: The length to expand the file to
 827  *
 828  * Simple function that handles the truncation of an eCryptfs inode and
 829  * its corresponding lower inode.
 830  *
 831  * Returns zero on success; non-zero otherwise
 832  */
 833 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 834 {
 835         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 836         struct iattr lower_ia = { .ia_valid = 0 };
 837         int rc;
 838
 839         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 840         if (rc)
 841                 return rc;
 842
 843         rc = truncate_upper(dentry, &ia, &lower_ia);
 844         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 845                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 846
 847                 inode_lock(d_inode(lower_dentry));
 848                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 849                 inode_unlock(d_inode(lower_dentry));
 850         }
 851         return rc;
 852 }
 853
 854 static int
 855 ecryptfs_permission(struct inode *inode, int mask)
 856 {
 857         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 858 }
 859
 860 /**
 861  * ecryptfs_setattr
 862  * @dentry: dentry handle to the inode to modify
 863  * @ia: Structure with flags of what to change and values
 864  *
 865  * Updates the metadata of an inode. If the update is to the size
 866  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 867  * of both the ecryptfs inode and the lower inode.
 868  *
 869  * All other metadata changes will be passed right to the lower filesystem,
 870  * and we will just update our inode to look like the lower.
 871  */
 872 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 873 {
 874         int rc = 0;
 875         struct dentry *lower_dentry;
 876         struct iattr lower_ia;
 877         struct inode *inode;
 878         struct inode *lower_inode;
 879         struct ecryptfs_crypt_stat *crypt_stat;
 880
 881         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 882         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
 883                 rc = ecryptfs_init_crypt_stat(crypt_stat);
 884                 if (rc)
 885                         return rc;
 886         }
 887         inode = d_inode(dentry);
 888         lower_inode = ecryptfs_inode_to_lower(inode);
 889         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 890         mutex_lock(&crypt_stat->cs_mutex);
 891         if (d_is_dir(dentry))
 892                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 893         else if (d_is_reg(dentry)
 894                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 895                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 896                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 897
 898                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 899                         dentry->d_sb)->mount_crypt_stat;
 900                 rc = ecryptfs_get_lower_file(dentry, inode);
 901                 if (rc) {
 902                         mutex_unlock(&crypt_stat->cs_mutex);
 903                         goto out;
 904                 }
 905                 rc = ecryptfs_read_metadata(dentry);
 906                 ecryptfs_put_lower_file(inode);
 907                 if (rc) {
 908                         if (!(mount_crypt_stat->flags
 909                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 910                                 rc = -EIO;
 911                                 printk(KERN_WARNING "Either the lower file "
 912                                        "is not in a valid eCryptfs format, "
 913                                        "or the key could not be retrieved. "
 914                                        "Plaintext passthrough mode is not "
 915                                        "enabled; returning -EIO\n");
 916                                 mutex_unlock(&crypt_stat->cs_mutex);
 917                                 goto out;
 918                         }
 919                         rc = 0;
 920                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 921                                                | ECRYPTFS_ENCRYPTED);
 922                 }
 923         }
 924         mutex_unlock(&crypt_stat->cs_mutex);
 925
 926         rc = setattr_prepare(dentry, ia);
 927         if (rc)
 928                 goto out;
 929         if (ia->ia_valid & ATTR_SIZE) {
 930                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 931                 if (rc)
 932                         goto out;
 933         }
 934
 935         memcpy(&lower_ia, ia, sizeof(lower_ia));
 936         if (ia->ia_valid & ATTR_FILE)
 937                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 938         if (ia->ia_valid & ATTR_SIZE) {
 939                 rc = truncate_upper(dentry, ia, &lower_ia);
 940                 if (rc < 0)
 941                         goto out;
 942         }
 943
 944         /*
 945          * mode change is for clearing setuid/setgid bits. Allow lower fs
 946          * to interpret this in its own way.
 947          */
 948         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 949                 lower_ia.ia_valid &= ~ATTR_MODE;
 950
 951         inode_lock(d_inode(lower_dentry));
 952         rc = notify_change(lower_dentry, &lower_ia, NULL);
 953         inode_unlock(d_inode(lower_dentry));
 954 out:
 955         fsstack_copy_attr_all(inode, lower_inode);
 956         return rc;
 957 }
 958
 959 static int ecryptfs_getattr_link(const struct path *path, struct kstat *stat,
 960                                  u32 request_mask, unsigned int flags)
 961 {
 962         struct dentry *dentry = path->dentry;
 963         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 964         int rc = 0;
 965
 966         mount_crypt_stat = &ecryptfs_superblock_to_private(
 967                                                 dentry->d_sb)->mount_crypt_stat;
 968         generic_fillattr(d_inode(dentry), stat);
 969         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 970                 char *target;
 971                 size_t targetsiz;
 972
 973                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 974                 if (!IS_ERR(target)) {
 975                         kfree(target);
 976                         stat->size = targetsiz;
 977                 } else {
 978                         rc = PTR_ERR(target);
 979                 }
 980         }
 981         return rc;
 982 }
 983
 984 static int ecryptfs_getattr(const struct path *path, struct kstat *stat,
 985                             u32 request_mask, unsigned int flags)
 986 {
 987         struct dentry *dentry = path->dentry;
 988         struct kstat lower_stat;
 989         int rc;
 990
 991         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
 992                          request_mask, flags);
 993         if (!rc) {
 994                 fsstack_copy_attr_all(d_inode(dentry),
 995                                       ecryptfs_inode_to_lower(d_inode(dentry)));
 996                 generic_fillattr(d_inode(dentry), stat);
 997                 stat->blocks = lower_stat.blocks;
 998         }
 999         return rc;
1000 }
1001
1002 int
1003 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1004                   const char *name, const void *value,
1005                   size_t size, int flags)
1006 {
1007         int rc;
1008         struct dentry *lower_dentry;
1009
1010         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1011         if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1012                 rc = -EOPNOTSUPP;
1013                 goto out;
1014         }
1015         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1016         if (!rc && inode)
1017                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1018 out:
1019         return rc;
1020 }
1021
1022 ssize_t
1023 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1024                         const char *name, void *value, size_t size)
1025 {
1026         int rc;
1027
1028         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1029                 rc = -EOPNOTSUPP;
1030                 goto out;
1031         }
1032         inode_lock(lower_inode);
1033         rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1034         inode_unlock(lower_inode);
1035 out:
1036         return rc;
1037 }
1038
1039 static ssize_t
1040 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1041                   const char *name, void *value, size_t size)
1042 {
1043         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1044                                        ecryptfs_inode_to_lower(inode),
1045                                        name, value, size);
1046 }
1047
1048 static ssize_t
1049 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1050 {
1051         int rc = 0;
1052         struct dentry *lower_dentry;
1053
1054         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1055         if (!d_inode(lower_dentry)->i_op->listxattr) {
1056                 rc = -EOPNOTSUPP;
1057                 goto out;
1058         }
1059         inode_lock(d_inode(lower_dentry));
1060         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1061         inode_unlock(d_inode(lower_dentry));
1062 out:
1063         return rc;
1064 }
1065
1066 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1067                                 const char *name)
1068 {
1069         int rc;
1070         struct dentry *lower_dentry;
1071         struct inode *lower_inode;
1072
1073         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1074         lower_inode = ecryptfs_inode_to_lower(inode);
1075         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1076                 rc = -EOPNOTSUPP;
1077                 goto out;
1078         }
1079         inode_lock(lower_inode);
1080         rc = __vfs_removexattr(lower_dentry, name);
1081         inode_unlock(lower_inode);
1082 out:
1083         return rc;
1084 }
1085
1086 const struct inode_operations ecryptfs_symlink_iops = {
1087         .get_link = ecryptfs_get_link,
1088         .permission = ecryptfs_permission,
1089         .setattr = ecryptfs_setattr,
1090         .getattr = ecryptfs_getattr_link,
1091         .listxattr = ecryptfs_listxattr,
1092 };
1093
1094 const struct inode_operations ecryptfs_dir_iops = {
1095         .create = ecryptfs_create,
1096         .lookup = ecryptfs_lookup,
1097         .link = ecryptfs_link,
1098         .unlink = ecryptfs_unlink,
1099         .symlink = ecryptfs_symlink,
1100         .mkdir = ecryptfs_mkdir,
1101         .rmdir = ecryptfs_rmdir,
1102         .mknod = ecryptfs_mknod,
1103         .rename = ecryptfs_rename,
1104         .permission = ecryptfs_permission,
1105         .setattr = ecryptfs_setattr,
1106         .listxattr = ecryptfs_listxattr,
1107 };
1108
1109 const struct inode_operations ecryptfs_main_iops = {
1110         .permission = ecryptfs_permission,
1111         .setattr = ecryptfs_setattr,
1112         .getattr = ecryptfs_getattr,
1113         .listxattr = ecryptfs_listxattr,
1114 };
1115
1116 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1117                               struct dentry *dentry, struct inode *inode,
1118                               const char *name, void *buffer, size_t size)
1119 {
1120         return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1121 }
1122
1123 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1124                               struct dentry *dentry, struct inode *inode,
1125                               const char *name, const void *value, size_t size,
1126                               int flags)
1127 {
1128         if (value)
1129                 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1130         else {
1131                 BUG_ON(flags != XATTR_REPLACE);
1132                 return ecryptfs_removexattr(dentry, inode, name);
1133         }
1134 }
1135
1136 const struct xattr_handler ecryptfs_xattr_handler = {
1137         .prefix = "",  /* match anything */
1138         .get = ecryptfs_xattr_get,
1139         .set = ecryptfs_xattr_set,
1140 };
1141
1142 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1143         &ecryptfs_xattr_handler,
1144         NULL
1145 };