fs/ecryptfs/inode.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /**
   3  * eCryptfs: Linux filesystem encryption layer
   4  *
   5  * Copyright (C) 1997-2004 Erez Zadok
   6  * Copyright (C) 2001-2004 Stony Brook University
   7  * Copyright (C) 2004-2007 International Business Machines Corp.
   8  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   9  *              Michael C. Thompsion <mcthomps@us.ibm.com>
  10  */
  11
  12 #include <linux/file.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/dcache.h>
  16 #include <linux/namei.h>
  17 #include <linux/mount.h>
  18 #include <linux/fs_stack.h>
  19 #include <linux/slab.h>
  20 #include <linux/xattr.h>
  21 #include <asm/unaligned.h>
  22 #include "ecryptfs_kernel.h"
  23
  24 static struct dentry *lock_parent(struct dentry *dentry)
  25 {
  26         struct dentry *dir;
  27
  28         dir = dget_parent(dentry);
  29         inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
  30         return dir;
  31 }
  32
  33 static void unlock_dir(struct dentry *dir)
  34 {
  35         inode_unlock(d_inode(dir));
  36         dput(dir);
  37 }
  38
  39 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
  40 {
  41         return ecryptfs_inode_to_lower(inode) == lower_inode;
  42 }
  43
  44 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
  45 {
  46         struct inode *lower_inode = opaque;
  47
  48         ecryptfs_set_inode_lower(inode, lower_inode);
  49         fsstack_copy_attr_all(inode, lower_inode);
  50         /* i_size will be overwritten for encrypted regular files */
  51         fsstack_copy_inode_size(inode, lower_inode);
  52         inode->i_ino = lower_inode->i_ino;
  53         inode->i_mapping->a_ops = &ecryptfs_aops;
  54
  55         if (S_ISLNK(inode->i_mode))
  56                 inode->i_op = &ecryptfs_symlink_iops;
  57         else if (S_ISDIR(inode->i_mode))
  58                 inode->i_op = &ecryptfs_dir_iops;
  59         else
  60                 inode->i_op = &ecryptfs_main_iops;
  61
  62         if (S_ISDIR(inode->i_mode))
  63                 inode->i_fop = &ecryptfs_dir_fops;
  64         else if (special_file(inode->i_mode))
  65                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
  66         else
  67                 inode->i_fop = &ecryptfs_main_fops;
  68
  69         return 0;
  70 }
  71
  72 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  73                                           struct super_block *sb)
  74 {
  75         struct inode *inode;
  76
  77         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  78                 return ERR_PTR(-EXDEV);
  79
  80         /* Reject dealing with casefold directories. */
  81         if (IS_CASEFOLDED(lower_inode)) {
  82                 pr_err_ratelimited("%s: Can't handle casefolded directory.\n",
  83                                    __func__);
  84                 return ERR_PTR(-EREMOTE);
  85         }
  86
  87         if (!igrab(lower_inode))
  88                 return ERR_PTR(-ESTALE);
  89         inode = iget5_locked(sb, (unsigned long)lower_inode,
  90                              ecryptfs_inode_test, ecryptfs_inode_set,
  91                              lower_inode);
  92         if (!inode) {
  93                 iput(lower_inode);
  94                 return ERR_PTR(-EACCES);
  95         }
  96         if (!(inode->i_state & I_NEW))
  97                 iput(lower_inode);
  98
  99         return inode;
 100 }
 101
 102 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 103                                  struct super_block *sb)
 104 {
 105         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 106
 107         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 108                 unlock_new_inode(inode);
 109
 110         return inode;
 111 }
 112
 113 /**
 114  * ecryptfs_interpose
 115  * @lower_dentry: Existing dentry in the lower filesystem
 116  * @dentry: ecryptfs' dentry
 117  * @sb: ecryptfs's super_block
 118  *
 119  * Interposes upper and lower dentries.
 120  *
 121  * Returns zero on success; non-zero otherwise
 122  */
 123 static int ecryptfs_interpose(struct dentry *lower_dentry,
 124                               struct dentry *dentry, struct super_block *sb)
 125 {
 126         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 127
 128         if (IS_ERR(inode))
 129                 return PTR_ERR(inode);
 130         d_instantiate(dentry, inode);
 131
 132         return 0;
 133 }
 134
 135 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 136                               struct inode *inode)
 137 {
 138         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 139         struct dentry *lower_dir_dentry;
 140         struct inode *lower_dir_inode;
 141         int rc;
 142
 143         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 144         lower_dir_inode = d_inode(lower_dir_dentry);
 145         inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
 146         dget(lower_dentry);     // don't even try to make the lower negative
 147         if (lower_dentry->d_parent != lower_dir_dentry)
 148                 rc = -EINVAL;
 149         else if (d_unhashed(lower_dentry))
 150                 rc = -EINVAL;
 151         else
 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 out_unlock:
 161         dput(lower_dentry);
 162         inode_unlock(lower_dir_inode);
 163         if (!rc)
 164                 d_drop(dentry);
 165         return rc;
 166 }
 167
 168 /**
 169  * ecryptfs_do_create
 170  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 171  * @ecryptfs_dentry: New file's dentry in ecryptfs
 172  * @mode: The mode of the new file
 173  *
 174  * Creates the underlying file and the eCryptfs inode which will link to
 175  * it. It will also update the eCryptfs directory inode to mimic the
 176  * stat of the lower directory inode.
 177  *
 178  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 179  */
 180 static struct inode *
 181 ecryptfs_do_create(struct inode *directory_inode,
 182                    struct dentry *ecryptfs_dentry, umode_t mode)
 183 {
 184         int rc;
 185         struct dentry *lower_dentry;
 186         struct dentry *lower_dir_dentry;
 187         struct inode *inode;
 188
 189         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 190         lower_dir_dentry = lock_parent(lower_dentry);
 191         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 192         if (rc) {
 193                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 194                        "rc = [%d]\n", __func__, rc);
 195                 inode = ERR_PTR(rc);
 196                 goto out_lock;
 197         }
 198         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 199                                      directory_inode->i_sb);
 200         if (IS_ERR(inode)) {
 201                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 202                 goto out_lock;
 203         }
 204         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 205         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 206 out_lock:
 207         unlock_dir(lower_dir_dentry);
 208         return inode;
 209 }
 210
 211 /**
 212  * ecryptfs_initialize_file
 213  *
 214  * Cause the file to be changed from a basic empty file to an ecryptfs
 215  * file with a header and first data page.
 216  *
 217  * Returns zero on success
 218  */
 219 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 220                              struct inode *ecryptfs_inode)
 221 {
 222         struct ecryptfs_crypt_stat *crypt_stat =
 223                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 224         int rc = 0;
 225
 226         if (S_ISDIR(ecryptfs_inode->i_mode)) {
 227                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 228                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 229                 goto out;
 230         }
 231         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 232         rc = ecryptfs_new_file_context(ecryptfs_inode);
 233         if (rc) {
 234                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 235                                 "context; rc = [%d]\n", rc);
 236                 goto out;
 237         }
 238         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 239         if (rc) {
 240                 printk(KERN_ERR "%s: Error attempting to initialize "
 241                         "the lower file for the dentry with name "
 242                         "[%pd]; rc = [%d]\n", __func__,
 243                         ecryptfs_dentry, rc);
 244                 goto out;
 245         }
 246         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 247         if (rc)
 248                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 249         ecryptfs_put_lower_file(ecryptfs_inode);
 250 out:
 251         return rc;
 252 }
 253
 254 /**
 255  * ecryptfs_create
 256  * @dir: The inode of the directory in which to create the file.
 257  * @dentry: The eCryptfs dentry
 258  * @mode: The mode of the new file.
 259  *
 260  * Creates a new file.
 261  *
 262  * Returns zero on success; non-zero on error condition
 263  */
 264 static int
 265 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 266                 umode_t mode, bool excl)
 267 {
 268         struct inode *ecryptfs_inode;
 269         int rc;
 270
 271         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 272                                             mode);
 273         if (IS_ERR(ecryptfs_inode)) {
 274                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 275                                 "lower filesystem\n");
 276                 rc = PTR_ERR(ecryptfs_inode);
 277                 goto out;
 278         }
 279         /* At this point, a file exists on "disk"; we need to make sure
 280          * that this on disk file is prepared to be an ecryptfs file */
 281         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 282         if (rc) {
 283                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 284                                    ecryptfs_inode);
 285                 iget_failed(ecryptfs_inode);
 286                 goto out;
 287         }
 288         d_instantiate_new(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 path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
 331         struct inode *inode, *lower_inode;
 332         struct ecryptfs_dentry_info *dentry_info;
 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         fsstack_copy_attr_atime(d_inode(dentry->d_parent),
 342                                 d_inode(path->dentry));
 343         BUG_ON(!d_count(lower_dentry));
 344
 345         ecryptfs_set_dentry_private(dentry, dentry_info);
 346         dentry_info->lower_path.mnt = mntget(path->mnt);
 347         dentry_info->lower_path.dentry = lower_dentry;
 348
 349         /*
 350          * negative dentry can go positive under us here - its parent is not
 351          * locked.  That's OK and that could happen just as we return from
 352          * ecryptfs_lookup() anyway.  Just need to be careful and fetch
 353          * ->d_inode only once - it's not stable here.
 354          */
 355         lower_inode = READ_ONCE(lower_dentry->d_inode);
 356
 357         if (!lower_inode) {
 358                 /* We want to add because we couldn't find in lower */
 359                 d_add(dentry, NULL);
 360                 return NULL;
 361         }
 362         inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
 363         if (IS_ERR(inode)) {
 364                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 365                        __func__, PTR_ERR(inode));
 366                 return ERR_CAST(inode);
 367         }
 368         if (S_ISREG(inode->i_mode)) {
 369                 rc = ecryptfs_i_size_read(dentry, inode);
 370                 if (rc) {
 371                         make_bad_inode(inode);
 372                         return ERR_PTR(rc);
 373                 }
 374         }
 375
 376         if (inode->i_state & I_NEW)
 377                 unlock_new_inode(inode);
 378         return d_splice_alias(inode, dentry);
 379 }
 380
 381 /**
 382  * ecryptfs_lookup
 383  * @ecryptfs_dir_inode: The eCryptfs directory inode
 384  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 385  * @flags: lookup flags
 386  *
 387  * Find a file on disk. If the file does not exist, then we'll add it to the
 388  * dentry cache and continue on to read it from the disk.
 389  */
 390 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 391                                       struct dentry *ecryptfs_dentry,
 392                                       unsigned int flags)
 393 {
 394         char *encrypted_and_encoded_name = NULL;
 395         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 396         struct dentry *lower_dir_dentry, *lower_dentry;
 397         const char *name = ecryptfs_dentry->d_name.name;
 398         size_t len = ecryptfs_dentry->d_name.len;
 399         struct dentry *res;
 400         int rc = 0;
 401
 402         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 403
 404         mount_crypt_stat = &ecryptfs_superblock_to_private(
 405                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
 406         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 407                 rc = ecryptfs_encrypt_and_encode_filename(
 408                         &encrypted_and_encoded_name, &len,
 409                         mount_crypt_stat, name, len);
 410                 if (rc) {
 411                         printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 412                                "filename; rc = [%d]\n", __func__, rc);
 413                         return ERR_PTR(rc);
 414                 }
 415                 name = encrypted_and_encoded_name;
 416         }
 417
 418         lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
 419         if (IS_ERR(lower_dentry)) {
 420                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 421                                 "[%ld] on lower_dentry = [%s]\n", __func__,
 422                                 PTR_ERR(lower_dentry),
 423                                 name);
 424                 res = ERR_CAST(lower_dentry);
 425         } else {
 426                 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
 427         }
 428         kfree(encrypted_and_encoded_name);
 429         return res;
 430 }
 431
 432 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 433                          struct dentry *new_dentry)
 434 {
 435         struct dentry *lower_old_dentry;
 436         struct dentry *lower_new_dentry;
 437         struct dentry *lower_dir_dentry;
 438         u64 file_size_save;
 439         int rc;
 440
 441         file_size_save = i_size_read(d_inode(old_dentry));
 442         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 443         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 444         dget(lower_old_dentry);
 445         dget(lower_new_dentry);
 446         lower_dir_dentry = lock_parent(lower_new_dentry);
 447         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 448                       lower_new_dentry, NULL);
 449         if (rc || d_really_is_negative(lower_new_dentry))
 450                 goto out_lock;
 451         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 452         if (rc)
 453                 goto out_lock;
 454         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 455         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 456         set_nlink(d_inode(old_dentry),
 457                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 458         i_size_write(d_inode(new_dentry), file_size_save);
 459 out_lock:
 460         unlock_dir(lower_dir_dentry);
 461         dput(lower_new_dentry);
 462         dput(lower_old_dentry);
 463         return rc;
 464 }
 465
 466 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 467 {
 468         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 469 }
 470
 471 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 472                             const char *symname)
 473 {
 474         int rc;
 475         struct dentry *lower_dentry;
 476         struct dentry *lower_dir_dentry;
 477         char *encoded_symname;
 478         size_t encoded_symlen;
 479         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 480
 481         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 482         dget(lower_dentry);
 483         lower_dir_dentry = lock_parent(lower_dentry);
 484         mount_crypt_stat = &ecryptfs_superblock_to_private(
 485                 dir->i_sb)->mount_crypt_stat;
 486         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 487                                                   &encoded_symlen,
 488                                                   mount_crypt_stat, symname,
 489                                                   strlen(symname));
 490         if (rc)
 491                 goto out_lock;
 492         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 493                          encoded_symname);
 494         kfree(encoded_symname);
 495         if (rc || d_really_is_negative(lower_dentry))
 496                 goto out_lock;
 497         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 498         if (rc)
 499                 goto out_lock;
 500         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 501         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 502 out_lock:
 503         unlock_dir(lower_dir_dentry);
 504         dput(lower_dentry);
 505         if (d_really_is_negative(dentry))
 506                 d_drop(dentry);
 507         return rc;
 508 }
 509
 510 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 511 {
 512         int rc;
 513         struct dentry *lower_dentry;
 514         struct dentry *lower_dir_dentry;
 515
 516         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 517         lower_dir_dentry = lock_parent(lower_dentry);
 518         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 519         if (rc || d_really_is_negative(lower_dentry))
 520                 goto out;
 521         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 522         if (rc)
 523                 goto out;
 524         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 525         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 526         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 527 out:
 528         unlock_dir(lower_dir_dentry);
 529         if (d_really_is_negative(dentry))
 530                 d_drop(dentry);
 531         return rc;
 532 }
 533
 534 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 535 {
 536         struct dentry *lower_dentry;
 537         struct dentry *lower_dir_dentry;
 538         struct inode *lower_dir_inode;
 539         int rc;
 540
 541         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 542         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 543         lower_dir_inode = d_inode(lower_dir_dentry);
 544
 545         inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
 546         dget(lower_dentry);     // don't even try to make the lower negative
 547         if (lower_dentry->d_parent != lower_dir_dentry)
 548                 rc = -EINVAL;
 549         else if (d_unhashed(lower_dentry))
 550                 rc = -EINVAL;
 551         else
 552                 rc = vfs_rmdir(lower_dir_inode, lower_dentry);
 553         if (!rc) {
 554                 clear_nlink(d_inode(dentry));
 555                 fsstack_copy_attr_times(dir, lower_dir_inode);
 556                 set_nlink(dir, lower_dir_inode->i_nlink);
 557         }
 558         dput(lower_dentry);
 559         inode_unlock(lower_dir_inode);
 560         if (!rc)
 561                 d_drop(dentry);
 562         return rc;
 563 }
 564
 565 static int
 566 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 567 {
 568         int rc;
 569         struct dentry *lower_dentry;
 570         struct dentry *lower_dir_dentry;
 571
 572         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 573         lower_dir_dentry = lock_parent(lower_dentry);
 574         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 575         if (rc || d_really_is_negative(lower_dentry))
 576                 goto out;
 577         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 578         if (rc)
 579                 goto out;
 580         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 581         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 582 out:
 583         unlock_dir(lower_dir_dentry);
 584         if (d_really_is_negative(dentry))
 585                 d_drop(dentry);
 586         return rc;
 587 }
 588
 589 static int
 590 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 591                 struct inode *new_dir, struct dentry *new_dentry,
 592                 unsigned int flags)
 593 {
 594         int rc;
 595         struct dentry *lower_old_dentry;
 596         struct dentry *lower_new_dentry;
 597         struct dentry *lower_old_dir_dentry;
 598         struct dentry *lower_new_dir_dentry;
 599         struct dentry *trap;
 600         struct inode *target_inode;
 601
 602         if (flags)
 603                 return -EINVAL;
 604
 605         lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent);
 606         lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent);
 607
 608         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 609         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 610
 611         target_inode = d_inode(new_dentry);
 612
 613         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 614         dget(lower_new_dentry);
 615         rc = -EINVAL;
 616         if (lower_old_dentry->d_parent != lower_old_dir_dentry)
 617                 goto out_lock;
 618         if (lower_new_dentry->d_parent != lower_new_dir_dentry)
 619                 goto out_lock;
 620         if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
 621                 goto out_lock;
 622         /* source should not be ancestor of target */
 623         if (trap == lower_old_dentry)
 624                 goto out_lock;
 625         /* target should not be ancestor of source */
 626         if (trap == lower_new_dentry) {
 627                 rc = -ENOTEMPTY;
 628                 goto out_lock;
 629         }
 630         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 631                         d_inode(lower_new_dir_dentry), lower_new_dentry,
 632                         NULL, 0);
 633         if (rc)
 634                 goto out_lock;
 635         if (target_inode)
 636                 fsstack_copy_attr_all(target_inode,
 637                                       ecryptfs_inode_to_lower(target_inode));
 638         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 639         if (new_dir != old_dir)
 640                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 641 out_lock:
 642         dput(lower_new_dentry);
 643         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 644         return rc;
 645 }
 646
 647 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 648 {
 649         DEFINE_DELAYED_CALL(done);
 650         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 651         const char *link;
 652         char *buf;
 653         int rc;
 654
 655         link = vfs_get_link(lower_dentry, &done);
 656         if (IS_ERR(link))
 657                 return ERR_CAST(link);
 658
 659         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 660                                                   link, strlen(link));
 661         do_delayed_call(&done);
 662         if (rc)
 663                 return ERR_PTR(rc);
 664
 665         return buf;
 666 }
 667
 668 static const char *ecryptfs_get_link(struct dentry *dentry,
 669                                      struct inode *inode,
 670                                      struct delayed_call *done)
 671 {
 672         size_t len;
 673         char *buf;
 674
 675         if (!dentry)
 676                 return ERR_PTR(-ECHILD);
 677
 678         buf = ecryptfs_readlink_lower(dentry, &len);
 679         if (IS_ERR(buf))
 680                 return buf;
 681         fsstack_copy_attr_atime(d_inode(dentry),
 682                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
 683         buf[len] = '\0';
 684         set_delayed_call(done, kfree_link, buf);
 685         return buf;
 686 }
 687
 688 /**
 689  * upper_size_to_lower_size
 690  * @crypt_stat: Crypt_stat associated with file
 691  * @upper_size: Size of the upper file
 692  *
 693  * Calculate the required size of the lower file based on the
 694  * specified size of the upper file. This calculation is based on the
 695  * number of headers in the underlying file and the extent size.
 696  *
 697  * Returns Calculated size of the lower file.
 698  */
 699 static loff_t
 700 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 701                          loff_t upper_size)
 702 {
 703         loff_t lower_size;
 704
 705         lower_size = ecryptfs_lower_header_size(crypt_stat);
 706         if (upper_size != 0) {
 707                 loff_t num_extents;
 708
 709                 num_extents = upper_size >> crypt_stat->extent_shift;
 710                 if (upper_size & ~crypt_stat->extent_mask)
 711                         num_extents++;
 712                 lower_size += (num_extents * crypt_stat->extent_size);
 713         }
 714         return lower_size;
 715 }
 716
 717 /**
 718  * truncate_upper
 719  * @dentry: The ecryptfs layer dentry
 720  * @ia: Address of the ecryptfs inode's attributes
 721  * @lower_ia: Address of the lower inode's attributes
 722  *
 723  * Function to handle truncations modifying the size of the file. Note
 724  * that the file sizes are interpolated. When expanding, we are simply
 725  * writing strings of 0's out. When truncating, we truncate the upper
 726  * inode and update the lower_ia according to the page index
 727  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 728  * the caller must use lower_ia in a call to notify_change() to perform
 729  * the truncation of the lower inode.
 730  *
 731  * Returns zero on success; non-zero otherwise
 732  */
 733 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 734                           struct iattr *lower_ia)
 735 {
 736         int rc = 0;
 737         struct inode *inode = d_inode(dentry);
 738         struct ecryptfs_crypt_stat *crypt_stat;
 739         loff_t i_size = i_size_read(inode);
 740         loff_t lower_size_before_truncate;
 741         loff_t lower_size_after_truncate;
 742
 743         if (unlikely((ia->ia_size == i_size))) {
 744                 lower_ia->ia_valid &= ~ATTR_SIZE;
 745                 return 0;
 746         }
 747         rc = ecryptfs_get_lower_file(dentry, inode);
 748         if (rc)
 749                 return rc;
 750         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 751         /* Switch on growing or shrinking file */
 752         if (ia->ia_size > i_size) {
 753                 char zero[] = { 0x00 };
 754
 755                 lower_ia->ia_valid &= ~ATTR_SIZE;
 756                 /* Write a single 0 at the last position of the file;
 757                  * this triggers code that will fill in 0's throughout
 758                  * the intermediate portion of the previous end of the
 759                  * file and the new and of the file */
 760                 rc = ecryptfs_write(inode, zero,
 761                                     (ia->ia_size - 1), 1);
 762         } else { /* ia->ia_size < i_size_read(inode) */
 763                 /* We're chopping off all the pages down to the page
 764                  * in which ia->ia_size is located. Fill in the end of
 765                  * that page from (ia->ia_size & ~PAGE_MASK) to
 766                  * PAGE_SIZE with zeros. */
 767                 size_t num_zeros = (PAGE_SIZE
 768                                     - (ia->ia_size & ~PAGE_MASK));
 769
 770                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 771                         truncate_setsize(inode, ia->ia_size);
 772                         lower_ia->ia_size = ia->ia_size;
 773                         lower_ia->ia_valid |= ATTR_SIZE;
 774                         goto out;
 775                 }
 776                 if (num_zeros) {
 777                         char *zeros_virt;
 778
 779                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 780                         if (!zeros_virt) {
 781                                 rc = -ENOMEM;
 782                                 goto out;
 783                         }
 784                         rc = ecryptfs_write(inode, zeros_virt,
 785                                             ia->ia_size, num_zeros);
 786                         kfree(zeros_virt);
 787                         if (rc) {
 788                                 printk(KERN_ERR "Error attempting to zero out "
 789                                        "the remainder of the end page on "
 790                                        "reducing truncate; rc = [%d]\n", rc);
 791                                 goto out;
 792                         }
 793                 }
 794                 truncate_setsize(inode, ia->ia_size);
 795                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 796                 if (rc) {
 797                         printk(KERN_ERR "Problem with "
 798                                "ecryptfs_write_inode_size_to_metadata; "
 799                                "rc = [%d]\n", rc);
 800                         goto out;
 801                 }
 802                 /* We are reducing the size of the ecryptfs file, and need to
 803                  * know if we need to reduce the size of the lower file. */
 804                 lower_size_before_truncate =
 805                     upper_size_to_lower_size(crypt_stat, i_size);
 806                 lower_size_after_truncate =
 807                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
 808                 if (lower_size_after_truncate < lower_size_before_truncate) {
 809                         lower_ia->ia_size = lower_size_after_truncate;
 810                         lower_ia->ia_valid |= ATTR_SIZE;
 811                 } else
 812                         lower_ia->ia_valid &= ~ATTR_SIZE;
 813         }
 814 out:
 815         ecryptfs_put_lower_file(inode);
 816         return rc;
 817 }
 818
 819 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 820 {
 821         struct ecryptfs_crypt_stat *crypt_stat;
 822         loff_t lower_oldsize, lower_newsize;
 823
 824         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 825         lower_oldsize = upper_size_to_lower_size(crypt_stat,
 826                                                  i_size_read(inode));
 827         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 828         if (lower_newsize > lower_oldsize) {
 829                 /*
 830                  * The eCryptfs inode and the new *lower* size are mixed here
 831                  * because we may not have the lower i_mutex held and/or it may
 832                  * not be appropriate to call inode_newsize_ok() with inodes
 833                  * from other filesystems.
 834                  */
 835                 return inode_newsize_ok(inode, lower_newsize);
 836         }
 837
 838         return 0;
 839 }
 840
 841 /**
 842  * ecryptfs_truncate
 843  * @dentry: The ecryptfs layer dentry
 844  * @new_length: The length to expand the file to
 845  *
 846  * Simple function that handles the truncation of an eCryptfs inode and
 847  * its corresponding lower inode.
 848  *
 849  * Returns zero on success; non-zero otherwise
 850  */
 851 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 852 {
 853         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 854         struct iattr lower_ia = { .ia_valid = 0 };
 855         int rc;
 856
 857         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 858         if (rc)
 859                 return rc;
 860
 861         rc = truncate_upper(dentry, &ia, &lower_ia);
 862         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 863                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 864
 865                 inode_lock(d_inode(lower_dentry));
 866                 rc = notify_change(lower_dentry, &lower_ia, NULL);
 867                 inode_unlock(d_inode(lower_dentry));
 868         }
 869         return rc;
 870 }
 871
 872 static int
 873 ecryptfs_permission(struct inode *inode, int mask)
 874 {
 875         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 876 }
 877
 878 /**
 879  * ecryptfs_setattr
 880  * @dentry: dentry handle to the inode to modify
 881  * @ia: Structure with flags of what to change and values
 882  *
 883  * Updates the metadata of an inode. If the update is to the size
 884  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 885  * of both the ecryptfs inode and the lower inode.
 886  *
 887  * All other metadata changes will be passed right to the lower filesystem,
 888  * and we will just update our inode to look like the lower.
 889  */
 890 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 891 {
 892         int rc = 0;
 893         struct dentry *lower_dentry;
 894         struct iattr lower_ia;
 895         struct inode *inode;
 896         struct inode *lower_inode;
 897         struct ecryptfs_crypt_stat *crypt_stat;
 898
 899         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 900         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
 901                 rc = ecryptfs_init_crypt_stat(crypt_stat);
 902                 if (rc)
 903                         return rc;
 904         }
 905         inode = d_inode(dentry);
 906         lower_inode = ecryptfs_inode_to_lower(inode);
 907         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 908         mutex_lock(&crypt_stat->cs_mutex);
 909         if (d_is_dir(dentry))
 910                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 911         else if (d_is_reg(dentry)
 912                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 913                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 914                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 915
 916                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 917                         dentry->d_sb)->mount_crypt_stat;
 918                 rc = ecryptfs_get_lower_file(dentry, inode);
 919                 if (rc) {
 920                         mutex_unlock(&crypt_stat->cs_mutex);
 921                         goto out;
 922                 }
 923                 rc = ecryptfs_read_metadata(dentry);
 924                 ecryptfs_put_lower_file(inode);
 925                 if (rc) {
 926                         if (!(mount_crypt_stat->flags
 927                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 928                                 rc = -EIO;
 929                                 printk(KERN_WARNING "Either the lower file "
 930                                        "is not in a valid eCryptfs format, "
 931                                        "or the key could not be retrieved. "
 932                                        "Plaintext passthrough mode is not "
 933                                        "enabled; returning -EIO\n");
 934                                 mutex_unlock(&crypt_stat->cs_mutex);
 935                                 goto out;
 936                         }
 937                         rc = 0;
 938                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 939                                                | ECRYPTFS_ENCRYPTED);
 940                 }
 941         }
 942         mutex_unlock(&crypt_stat->cs_mutex);
 943
 944         rc = setattr_prepare(dentry, ia);
 945         if (rc)
 946                 goto out;
 947         if (ia->ia_valid & ATTR_SIZE) {
 948                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 949                 if (rc)
 950                         goto out;
 951         }
 952
 953         memcpy(&lower_ia, ia, sizeof(lower_ia));
 954         if (ia->ia_valid & ATTR_FILE)
 955                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 956         if (ia->ia_valid & ATTR_SIZE) {
 957                 rc = truncate_upper(dentry, ia, &lower_ia);
 958                 if (rc < 0)
 959                         goto out;
 960         }
 961
 962         /*
 963          * mode change is for clearing setuid/setgid bits. Allow lower fs
 964          * to interpret this in its own way.
 965          */
 966         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 967                 lower_ia.ia_valid &= ~ATTR_MODE;
 968
 969         inode_lock(d_inode(lower_dentry));
 970         rc = notify_change(lower_dentry, &lower_ia, NULL);
 971         inode_unlock(d_inode(lower_dentry));
 972 out:
 973         fsstack_copy_attr_all(inode, lower_inode);
 974         return rc;
 975 }
 976
 977 static int ecryptfs_getattr_link(const struct path *path, struct kstat *stat,
 978                                  u32 request_mask, unsigned int flags)
 979 {
 980         struct dentry *dentry = path->dentry;
 981         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 982         int rc = 0;
 983
 984         mount_crypt_stat = &ecryptfs_superblock_to_private(
 985                                                 dentry->d_sb)->mount_crypt_stat;
 986         generic_fillattr(d_inode(dentry), stat);
 987         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 988                 char *target;
 989                 size_t targetsiz;
 990
 991                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
 992                 if (!IS_ERR(target)) {
 993                         kfree(target);
 994                         stat->size = targetsiz;
 995                 } else {
 996                         rc = PTR_ERR(target);
 997                 }
 998         }
 999         return rc;
1000 }
1001
1002 static int ecryptfs_getattr(const struct path *path, struct kstat *stat,
1003                             u32 request_mask, unsigned int flags)
1004 {
1005         struct dentry *dentry = path->dentry;
1006         struct kstat lower_stat;
1007         int rc;
1008
1009         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
1010                          request_mask, flags);
1011         if (!rc) {
1012                 fsstack_copy_attr_all(d_inode(dentry),
1013                                       ecryptfs_inode_to_lower(d_inode(dentry)));
1014                 generic_fillattr(d_inode(dentry), stat);
1015                 stat->blocks = lower_stat.blocks;
1016         }
1017         return rc;
1018 }
1019
1020 int
1021 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1022                   const char *name, const void *value,
1023                   size_t size, int flags)
1024 {
1025         int rc;
1026         struct dentry *lower_dentry;
1027
1028         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1029         if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1030                 rc = -EOPNOTSUPP;
1031                 goto out;
1032         }
1033         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1034         if (!rc && inode)
1035                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1036 out:
1037         return rc;
1038 }
1039
1040 ssize_t
1041 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1042                         const char *name, void *value, size_t size)
1043 {
1044         int rc;
1045
1046         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1047                 rc = -EOPNOTSUPP;
1048                 goto out;
1049         }
1050         inode_lock(lower_inode);
1051         rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1052         inode_unlock(lower_inode);
1053 out:
1054         return rc;
1055 }
1056
1057 static ssize_t
1058 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1059                   const char *name, void *value, size_t size)
1060 {
1061         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1062                                        ecryptfs_inode_to_lower(inode),
1063                                        name, value, size);
1064 }
1065
1066 static ssize_t
1067 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1068 {
1069         int rc = 0;
1070         struct dentry *lower_dentry;
1071
1072         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1073         if (!d_inode(lower_dentry)->i_op->listxattr) {
1074                 rc = -EOPNOTSUPP;
1075                 goto out;
1076         }
1077         inode_lock(d_inode(lower_dentry));
1078         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1079         inode_unlock(d_inode(lower_dentry));
1080 out:
1081         return rc;
1082 }
1083
1084 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1085                                 const char *name)
1086 {
1087         int rc;
1088         struct dentry *lower_dentry;
1089         struct inode *lower_inode;
1090
1091         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1092         lower_inode = ecryptfs_inode_to_lower(inode);
1093         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1094                 rc = -EOPNOTSUPP;
1095                 goto out;
1096         }
1097         inode_lock(lower_inode);
1098         rc = __vfs_removexattr(lower_dentry, name);
1099         inode_unlock(lower_inode);
1100 out:
1101         return rc;
1102 }
1103
1104 const struct inode_operations ecryptfs_symlink_iops = {
1105         .get_link = ecryptfs_get_link,
1106         .permission = ecryptfs_permission,
1107         .setattr = ecryptfs_setattr,
1108         .getattr = ecryptfs_getattr_link,
1109         .listxattr = ecryptfs_listxattr,
1110 };
1111
1112 const struct inode_operations ecryptfs_dir_iops = {
1113         .create = ecryptfs_create,
1114         .lookup = ecryptfs_lookup,
1115         .link = ecryptfs_link,
1116         .unlink = ecryptfs_unlink,
1117         .symlink = ecryptfs_symlink,
1118         .mkdir = ecryptfs_mkdir,
1119         .rmdir = ecryptfs_rmdir,
1120         .mknod = ecryptfs_mknod,
1121         .rename = ecryptfs_rename,
1122         .permission = ecryptfs_permission,
1123         .setattr = ecryptfs_setattr,
1124         .listxattr = ecryptfs_listxattr,
1125 };
1126
1127 const struct inode_operations ecryptfs_main_iops = {
1128         .permission = ecryptfs_permission,
1129         .setattr = ecryptfs_setattr,
1130         .getattr = ecryptfs_getattr,
1131         .listxattr = ecryptfs_listxattr,
1132 };
1133
1134 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1135                               struct dentry *dentry, struct inode *inode,
1136                               const char *name, void *buffer, size_t size)
1137 {
1138         return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1139 }
1140
1141 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1142                               struct dentry *dentry, struct inode *inode,
1143                               const char *name, const void *value, size_t size,
1144                               int flags)
1145 {
1146         if (value)
1147                 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1148         else {
1149                 BUG_ON(flags != XATTR_REPLACE);
1150                 return ecryptfs_removexattr(dentry, inode, name);
1151         }
1152 }
1153
1154 static const struct xattr_handler ecryptfs_xattr_handler = {
1155         .prefix = "",  /* match anything */
1156         .get = ecryptfs_xattr_get,
1157         .set = ecryptfs_xattr_set,
1158 };
1159
1160 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1161         &ecryptfs_xattr_handler,
1162         NULL
1163 };