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