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