SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/ecryptfs/inode.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2004 Erez Zadok
   5  * Copyright (C) 2001-2004 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #include <linux/file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/dcache.h>
  30 #include <linux/namei.h>
  31 #include <linux/mount.h>
  32 #include <linux/crypto.h>
  33 #include <linux/fs_stack.h>
  34 #include "ecryptfs_kernel.h"
  35
  36 static struct dentry *lock_parent(struct dentry *dentry)
  37 {
  38         struct dentry *dir;
  39
  40         dir = dget(dentry->d_parent);
  41         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
  42         return dir;
  43 }
  44
  45 static void unlock_parent(struct dentry *dentry)
  46 {
  47         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
  48         dput(dentry->d_parent);
  49 }
  50
  51 static void unlock_dir(struct dentry *dir)
  52 {
  53         mutex_unlock(&dir->d_inode->i_mutex);
  54         dput(dir);
  55 }
  56
  57 /**
  58  * ecryptfs_create_underlying_file
  59  * @lower_dir_inode: inode of the parent in the lower fs of the new file
  60  * @lower_dentry: New file's dentry in the lower fs
  61  * @ecryptfs_dentry: New file's dentry in ecryptfs
  62  * @mode: The mode of the new file
  63  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  64  *
  65  * Creates the file in the lower file system.
  66  *
  67  * Returns zero on success; non-zero on error condition
  68  */
  69 static int
  70 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
  71                                 struct dentry *dentry, int mode,
  72                                 struct nameidata *nd)
  73 {
  74         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  75         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  76         struct dentry *dentry_save;
  77         struct vfsmount *vfsmount_save;
  78         int rc;
  79
  80         dentry_save = nd->dentry;
  81         vfsmount_save = nd->mnt;
  82         nd->dentry = lower_dentry;
  83         nd->mnt = lower_mnt;
  84         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
  85         nd->dentry = dentry_save;
  86         nd->mnt = vfsmount_save;
  87         return rc;
  88 }
  89
  90 /**
  91  * ecryptfs_do_create
  92  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
  93  * @ecryptfs_dentry: New file's dentry in ecryptfs
  94  * @mode: The mode of the new file
  95  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  96  *
  97  * Creates the underlying file and the eCryptfs inode which will link to
  98  * it. It will also update the eCryptfs directory inode to mimic the
  99  * stat of the lower directory inode.
 100  *
 101  * Returns zero on success; non-zero on error condition
 102  */
 103 static int
 104 ecryptfs_do_create(struct inode *directory_inode,
 105                    struct dentry *ecryptfs_dentry, int mode,
 106                    struct nameidata *nd)
 107 {
 108         int rc;
 109         struct dentry *lower_dentry;
 110         struct dentry *lower_dir_dentry;
 111
 112         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 113         lower_dir_dentry = lock_parent(lower_dentry);
 114         if (unlikely(IS_ERR(lower_dir_dentry))) {
 115                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 116                                 "dentry\n");
 117                 rc = PTR_ERR(lower_dir_dentry);
 118                 goto out;
 119         }
 120         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 121                                              ecryptfs_dentry, mode, nd);
 122         if (unlikely(rc)) {
 123                 ecryptfs_printk(KERN_ERR,
 124                                 "Failure to create underlying file\n");
 125                 goto out_lock;
 126         }
 127         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 128                                 directory_inode->i_sb, 0);
 129         if (rc) {
 130                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 131                 goto out_lock;
 132         }
 133         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
 134         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
 135 out_lock:
 136         unlock_dir(lower_dir_dentry);
 137 out:
 138         return rc;
 139 }
 140
 141 /**
 142  * grow_file
 143  * @ecryptfs_dentry: the ecryptfs dentry
 144  * @lower_file: The lower file
 145  * @inode: The ecryptfs inode
 146  * @lower_inode: The lower inode
 147  *
 148  * This is the code which will grow the file to its correct size.
 149  */
 150 static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
 151                      struct inode *inode, struct inode *lower_inode)
 152 {
 153         int rc = 0;
 154         struct file fake_file;
 155         struct ecryptfs_file_info tmp_file_info;
 156
 157         memset(&fake_file, 0, sizeof(fake_file));
 158         fake_file.f_path.dentry = ecryptfs_dentry;
 159         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 160         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 161         ecryptfs_set_file_lower(&fake_file, lower_file);
 162         rc = ecryptfs_fill_zeros(&fake_file, 1);
 163         if (rc) {
 164                 ecryptfs_inode_to_private(inode)->crypt_stat.flags |=
 165                         ECRYPTFS_SECURITY_WARNING;
 166                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
 167                                 "in file; rc = [%d]\n", rc);
 168                 goto out;
 169         }
 170         i_size_write(inode, 0);
 171         rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode,
 172                         inode, ecryptfs_dentry,
 173                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 174         ecryptfs_inode_to_private(inode)->crypt_stat.flags |= ECRYPTFS_NEW_FILE;
 175 out:
 176         return rc;
 177 }
 178
 179 /**
 180  * ecryptfs_initialize_file
 181  *
 182  * Cause the file to be changed from a basic empty file to an ecryptfs
 183  * file with a header and first data page.
 184  *
 185  * Returns zero on success
 186  */
 187 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 188 {
 189         int rc = 0;
 190         int lower_flags;
 191         struct ecryptfs_crypt_stat *crypt_stat;
 192         struct dentry *lower_dentry;
 193         struct file *lower_file;
 194         struct inode *inode, *lower_inode;
 195         struct vfsmount *lower_mnt;
 196
 197         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 198         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
 199                         lower_dentry->d_name.name);
 200         inode = ecryptfs_dentry->d_inode;
 201         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 202         lower_flags = ((O_CREAT | O_TRUNC) & O_ACCMODE) | O_RDWR;
 203         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 204         /* Corresponding fput() at end of this function */
 205         rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 206                                       lower_flags);
 207         if (rc) {
 208                 ecryptfs_printk(KERN_ERR,
 209                                 "Error opening dentry; rc = [%i]\n", rc);
 210                 goto out;
 211         }
 212         lower_inode = lower_dentry->d_inode;
 213         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 214                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 215                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 216                 goto out_fput;
 217         }
 218         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
 219         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 220         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 221         if (rc) {
 222                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
 223                                 "context\n");
 224                 goto out_fput;
 225         }
 226         rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
 227         if (rc) {
 228                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
 229                 goto out_fput;
 230         }
 231         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
 232 out_fput:
 233         rc = ecryptfs_close_lower_file(lower_file);
 234         if (rc)
 235                 printk(KERN_ERR "Error closing lower_file\n");
 236 out:
 237         return rc;
 238 }
 239
 240 /**
 241  * ecryptfs_create
 242  * @dir: The inode of the directory in which to create the file.
 243  * @dentry: The eCryptfs dentry
 244  * @mode: The mode of the new file.
 245  * @nd: nameidata
 246  *
 247  * Creates a new file.
 248  *
 249  * Returns zero on success; non-zero on error condition
 250  */
 251 static int
 252 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 253                 int mode, struct nameidata *nd)
 254 {
 255         int rc;
 256
 257         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 258         if (unlikely(rc)) {
 259                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 260                                 "lower filesystem\n");
 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);
 266 out:
 267         return rc;
 268 }
 269
 270 /**
 271  * ecryptfs_lookup
 272  * @dir: inode
 273  * @dentry: The dentry
 274  * @nd: nameidata, may be NULL
 275  *
 276  * Find a file on disk. If the file does not exist, then we'll add it to the
 277  * dentry cache and continue on to read it from the disk.
 278  */
 279 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 280                                       struct nameidata *nd)
 281 {
 282         int rc = 0;
 283         struct dentry *lower_dir_dentry;
 284         struct dentry *lower_dentry;
 285         struct vfsmount *lower_mnt;
 286         char *encoded_name;
 287         int encoded_namelen;
 288         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 289         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 290         char *page_virt = NULL;
 291         struct inode *lower_inode;
 292         u64 file_size;
 293
 294         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 295         dentry->d_op = &ecryptfs_dops;
 296         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 297             || (dentry->d_name.len == 2
 298                 && !strcmp(dentry->d_name.name, ".."))) {
 299                 d_drop(dentry);
 300                 goto out;
 301         }
 302         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 303                                                    dentry->d_name.name,
 304                                                    dentry->d_name.len,
 305                                                    &encoded_name);
 306         if (encoded_namelen < 0) {
 307                 rc = encoded_namelen;
 308                 d_drop(dentry);
 309                 goto out;
 310         }
 311         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 312                         "= [%d]\n", encoded_name, encoded_namelen);
 313         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 314                                       encoded_namelen - 1);
 315         kfree(encoded_name);
 316         if (IS_ERR(lower_dentry)) {
 317                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 318                 rc = PTR_ERR(lower_dentry);
 319                 d_drop(dentry);
 320                 goto out;
 321         }
 322         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 323         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 324                 "d_name.name = [%s]\n", lower_dentry,
 325                 lower_dentry->d_name.name);
 326         lower_inode = lower_dentry->d_inode;
 327         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 328         BUG_ON(!atomic_read(&lower_dentry->d_count));
 329         ecryptfs_set_dentry_private(dentry,
 330                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 331                                                      GFP_KERNEL));
 332         if (!ecryptfs_dentry_to_private(dentry)) {
 333                 rc = -ENOMEM;
 334                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 335                                 "to allocate ecryptfs_dentry_info struct\n");
 336                 goto out_dput;
 337         }
 338         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 339         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 340         if (!lower_dentry->d_inode) {
 341                 /* We want to add because we couldn't find in lower */
 342                 d_add(dentry, NULL);
 343                 goto out;
 344         }
 345         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 346         if (rc) {
 347                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 348                 goto out_dput;
 349         }
 350         if (S_ISDIR(lower_inode->i_mode)) {
 351                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 352                 goto out;
 353         }
 354         if (S_ISLNK(lower_inode->i_mode)) {
 355                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 356                 goto out;
 357         }
 358         if (special_file(lower_inode->i_mode)) {
 359                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
 360                 goto out;
 361         }
 362         if (!nd) {
 363                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 364                                 "as we *think* we are about to unlink\n");
 365                 goto out;
 366         }
 367         /* Released in this function */
 368         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 369                                       GFP_USER);
 370         if (!page_virt) {
 371                 rc = -ENOMEM;
 372                 ecryptfs_printk(KERN_ERR,
 373                                 "Cannot ecryptfs_kmalloc a page\n");
 374                 goto out_dput;
 375         }
 376         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 377         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 378                 ecryptfs_set_default_sizes(crypt_stat);
 379         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
 380                                                       nd->mnt);
 381         if (rc) {
 382                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 383                 if (rc) {
 384                         printk(KERN_DEBUG "Valid metadata not found in header "
 385                                "region or xattr region; treating file as "
 386                                "unencrypted\n");
 387                         rc = 0;
 388                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 389                         goto out;
 390                 }
 391                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 392         }
 393         mount_crypt_stat = &ecryptfs_superblock_to_private(
 394                 dentry->d_sb)->mount_crypt_stat;
 395         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 396                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 397                         file_size = ((crypt_stat->extent_size
 398                                       * crypt_stat->num_header_extents_at_front)
 399                                      + i_size_read(lower_dentry->d_inode));
 400                 else
 401                         file_size = i_size_read(lower_dentry->d_inode);
 402         } else {
 403                 memcpy(&file_size, page_virt, sizeof(file_size));
 404                 file_size = be64_to_cpu(file_size);
 405         }
 406         i_size_write(dentry->d_inode, (loff_t)file_size);
 407         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 408         goto out;
 409
 410 out_dput:
 411         dput(lower_dentry);
 412         d_drop(dentry);
 413 out:
 414         return ERR_PTR(rc);
 415 }
 416
 417 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 418                          struct dentry *new_dentry)
 419 {
 420         struct dentry *lower_old_dentry;
 421         struct dentry *lower_new_dentry;
 422         struct dentry *lower_dir_dentry;
 423         u64 file_size_save;
 424         int rc;
 425
 426         file_size_save = i_size_read(old_dentry->d_inode);
 427         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 428         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 429         dget(lower_old_dentry);
 430         dget(lower_new_dentry);
 431         lower_dir_dentry = lock_parent(lower_new_dentry);
 432         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 433                       lower_new_dentry);
 434         if (rc || !lower_new_dentry->d_inode)
 435                 goto out_lock;
 436         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 437         if (rc)
 438                 goto out_lock;
 439         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 440         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 441         old_dentry->d_inode->i_nlink =
 442                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 443         i_size_write(new_dentry->d_inode, file_size_save);
 444 out_lock:
 445         unlock_dir(lower_dir_dentry);
 446         dput(lower_new_dentry);
 447         dput(lower_old_dentry);
 448         d_drop(lower_old_dentry);
 449         d_drop(new_dentry);
 450         d_drop(old_dentry);
 451         return rc;
 452 }
 453
 454 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 455 {
 456         int rc = 0;
 457         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 458         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 459
 460         lock_parent(lower_dentry);
 461         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 462         if (rc) {
 463                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 464                 goto out_unlock;
 465         }
 466         fsstack_copy_attr_times(dir, lower_dir_inode);
 467         dentry->d_inode->i_nlink =
 468                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 469         dentry->d_inode->i_ctime = dir->i_ctime;
 470 out_unlock:
 471         unlock_parent(lower_dentry);
 472         return rc;
 473 }
 474
 475 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 476                             const char *symname)
 477 {
 478         int rc;
 479         struct dentry *lower_dentry;
 480         struct dentry *lower_dir_dentry;
 481         umode_t mode;
 482         char *encoded_symname;
 483         int encoded_symlen;
 484         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 485
 486         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 487         dget(lower_dentry);
 488         lower_dir_dentry = lock_parent(lower_dentry);
 489         mode = S_IALLUGO;
 490         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 491                                                   strlen(symname),
 492                                                   &encoded_symname);
 493         if (encoded_symlen < 0) {
 494                 rc = encoded_symlen;
 495                 goto out_lock;
 496         }
 497         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 498                          encoded_symname, mode);
 499         kfree(encoded_symname);
 500         if (rc || !lower_dentry->d_inode)
 501                 goto out_lock;
 502         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 503         if (rc)
 504                 goto out_lock;
 505         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 506         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 507 out_lock:
 508         unlock_dir(lower_dir_dentry);
 509         dput(lower_dentry);
 510         if (!dentry->d_inode)
 511                 d_drop(dentry);
 512         return rc;
 513 }
 514
 515 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 516 {
 517         int rc;
 518         struct dentry *lower_dentry;
 519         struct dentry *lower_dir_dentry;
 520
 521         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 522         lower_dir_dentry = lock_parent(lower_dentry);
 523         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 524         if (rc || !lower_dentry->d_inode)
 525                 goto out;
 526         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 527         if (rc)
 528                 goto out;
 529         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 530         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 531         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 532 out:
 533         unlock_dir(lower_dir_dentry);
 534         if (!dentry->d_inode)
 535                 d_drop(dentry);
 536         return rc;
 537 }
 538
 539 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 540 {
 541         struct dentry *lower_dentry;
 542         struct dentry *lower_dir_dentry;
 543         int rc;
 544
 545         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 546         dget(dentry);
 547         lower_dir_dentry = lock_parent(lower_dentry);
 548         dget(lower_dentry);
 549         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 550         dput(lower_dentry);
 551         if (!rc)
 552                 d_delete(lower_dentry);
 553         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 554         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 555         unlock_dir(lower_dir_dentry);
 556         if (!rc)
 557                 d_drop(dentry);
 558         dput(dentry);
 559         return rc;
 560 }
 561
 562 static int
 563 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 564 {
 565         int rc;
 566         struct dentry *lower_dentry;
 567         struct dentry *lower_dir_dentry;
 568
 569         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 570         lower_dir_dentry = lock_parent(lower_dentry);
 571         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 572         if (rc || !lower_dentry->d_inode)
 573                 goto out;
 574         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 575         if (rc)
 576                 goto out;
 577         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 578         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 579 out:
 580         unlock_dir(lower_dir_dentry);
 581         if (!dentry->d_inode)
 582                 d_drop(dentry);
 583         return rc;
 584 }
 585
 586 static int
 587 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 588                 struct inode *new_dir, struct dentry *new_dentry)
 589 {
 590         int rc;
 591         struct dentry *lower_old_dentry;
 592         struct dentry *lower_new_dentry;
 593         struct dentry *lower_old_dir_dentry;
 594         struct dentry *lower_new_dir_dentry;
 595
 596         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 597         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 598         dget(lower_old_dentry);
 599         dget(lower_new_dentry);
 600         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 601         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 602         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 603         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 604                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 605         if (rc)
 606                 goto out_lock;
 607         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 608         if (new_dir != old_dir)
 609                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 610 out_lock:
 611         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 612         dput(lower_new_dentry->d_parent);
 613         dput(lower_old_dentry->d_parent);
 614         dput(lower_new_dentry);
 615         dput(lower_old_dentry);
 616         return rc;
 617 }
 618
 619 static int
 620 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 621 {
 622         int rc;
 623         struct dentry *lower_dentry;
 624         char *decoded_name;
 625         char *lower_buf;
 626         mm_segment_t old_fs;
 627         struct ecryptfs_crypt_stat *crypt_stat;
 628
 629         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 630         if (!lower_dentry->d_inode->i_op ||
 631             !lower_dentry->d_inode->i_op->readlink) {
 632                 rc = -EINVAL;
 633                 goto out;
 634         }
 635         /* Released in this function */
 636         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 637         if (lower_buf == NULL) {
 638                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 639                 rc = -ENOMEM;
 640                 goto out;
 641         }
 642         old_fs = get_fs();
 643         set_fs(get_ds());
 644         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 645                         "lower_dentry->d_name.name = [%s]\n",
 646                         lower_dentry->d_name.name);
 647         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 648                                                    (char __user *)lower_buf,
 649                                                    bufsiz);
 650         set_fs(old_fs);
 651         if (rc >= 0) {
 652                 crypt_stat = NULL;
 653                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 654                                               &decoded_name);
 655                 if (rc == -ENOMEM)
 656                         goto out_free_lower_buf;
 657                 if (rc > 0) {
 658                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 659                                         "to userspace: [%*s]\n", rc,
 660                                         decoded_name);
 661                         if (copy_to_user(buf, decoded_name, rc))
 662                                 rc = -EFAULT;
 663                 }
 664                 kfree(decoded_name);
 665                 fsstack_copy_attr_atime(dentry->d_inode,
 666                                         lower_dentry->d_inode);
 667         }
 668 out_free_lower_buf:
 669         kfree(lower_buf);
 670 out:
 671         return rc;
 672 }
 673
 674 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 675 {
 676         char *buf;
 677         int len = PAGE_SIZE, rc;
 678         mm_segment_t old_fs;
 679
 680         /* Released in ecryptfs_put_link(); only release here on error */
 681         buf = kmalloc(len, GFP_KERNEL);
 682         if (!buf) {
 683                 rc = -ENOMEM;
 684                 goto out;
 685         }
 686         old_fs = get_fs();
 687         set_fs(get_ds());
 688         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 689                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 690         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 691         buf[rc] = '\0';
 692         set_fs(old_fs);
 693         if (rc < 0)
 694                 goto out_free;
 695         rc = 0;
 696         nd_set_link(nd, buf);
 697         goto out;
 698 out_free:
 699         kfree(buf);
 700 out:
 701         return ERR_PTR(rc);
 702 }
 703
 704 static void
 705 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 706 {
 707         /* Free the char* */
 708         kfree(nd_get_link(nd));
 709 }
 710
 711 /**
 712  * upper_size_to_lower_size
 713  * @crypt_stat: Crypt_stat associated with file
 714  * @upper_size: Size of the upper file
 715  *
 716  * Calculate the requried size of the lower file based on the
 717  * specified size of the upper file. This calculation is based on the
 718  * number of headers in the underlying file and the extent size.
 719  *
 720  * Returns Calculated size of the lower file.
 721  */
 722 static loff_t
 723 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 724                          loff_t upper_size)
 725 {
 726         loff_t lower_size;
 727
 728         lower_size = (crypt_stat->extent_size
 729                       * crypt_stat->num_header_extents_at_front);
 730         if (upper_size != 0) {
 731                 loff_t num_extents;
 732
 733                 num_extents = upper_size >> crypt_stat->extent_shift;
 734                 if (upper_size & ~crypt_stat->extent_mask)
 735                         num_extents++;
 736                 lower_size += (num_extents * crypt_stat->extent_size);
 737         }
 738         return lower_size;
 739 }
 740
 741 /**
 742  * ecryptfs_truncate
 743  * @dentry: The ecryptfs layer dentry
 744  * @new_length: The length to expand the file to
 745  *
 746  * Function to handle truncations modifying the size of the file. Note
 747  * that the file sizes are interpolated. When expanding, we are simply
 748  * writing strings of 0's out. When truncating, we need to modify the
 749  * underlying file size according to the page index interpolations.
 750  *
 751  * Returns zero on success; non-zero otherwise
 752  */
 753 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 754 {
 755         int rc = 0;
 756         struct inode *inode = dentry->d_inode;
 757         struct dentry *lower_dentry;
 758         struct vfsmount *lower_mnt;
 759         struct file fake_ecryptfs_file, *lower_file = NULL;
 760         struct ecryptfs_crypt_stat *crypt_stat;
 761         loff_t i_size = i_size_read(inode);
 762         loff_t lower_size_before_truncate;
 763         loff_t lower_size_after_truncate;
 764
 765         if (unlikely((new_length == i_size)))
 766                 goto out;
 767         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 768         /* Set up a fake ecryptfs file, this is used to interface with
 769          * the file in the underlying filesystem so that the
 770          * truncation has an effect there as well. */
 771         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 772         fake_ecryptfs_file.f_path.dentry = dentry;
 773         /* Released at out_free: label */
 774         ecryptfs_set_file_private(&fake_ecryptfs_file,
 775                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 776                                                    GFP_KERNEL));
 777         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 778                 rc = -ENOMEM;
 779                 goto out;
 780         }
 781         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 782         /* This dget & mntget is released through fput at out_fput: */
 783         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 784         rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 785                                       O_RDWR);
 786         if (rc) {
 787                 ecryptfs_printk(KERN_ERR,
 788                                 "Error opening dentry; rc = [%i]\n", rc);
 789                 goto out_free;
 790         }
 791         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 792         /* Switch on growing or shrinking file */
 793         if (new_length > i_size) {
 794                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 795                 if (rc) {
 796                         ecryptfs_printk(KERN_ERR,
 797                                         "Problem with fill_zeros\n");
 798                         goto out_fput;
 799                 }
 800                 i_size_write(inode, new_length);
 801                 rc = ecryptfs_write_inode_size_to_metadata(
 802                         lower_file, lower_dentry->d_inode, inode, dentry,
 803                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 804                 if (rc) {
 805                         printk(KERN_ERR "Problem with "
 806                                "ecryptfs_write_inode_size_to_metadata; "
 807                                "rc = [%d]\n", rc);
 808                         goto out_fput;
 809                 }
 810         } else { /* new_length < i_size_read(inode) */
 811                 pgoff_t index = 0;
 812                 int end_pos_in_page = -1;
 813
 814                 if (new_length != 0) {
 815                         index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
 816                         end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
 817                 }
 818                 if (end_pos_in_page != (PAGE_CACHE_SIZE - 1)) {
 819                         rc = ecryptfs_write_zeros(&fake_ecryptfs_file,
 820                                                   index,
 821                                                   (end_pos_in_page + 1),
 822                                                   ((PAGE_CACHE_SIZE - 1)
 823                                                    - end_pos_in_page));
 824                         if (rc) {
 825                                 printk(KERN_ERR "Error attempting to zero out "
 826                                        "the remainder of the end page on "
 827                                        "reducing truncate; rc = [%d]\n", rc);
 828                                 goto out_fput;
 829                         }
 830                 }
 831                 vmtruncate(inode, new_length);
 832                 rc = ecryptfs_write_inode_size_to_metadata(
 833                         lower_file, lower_dentry->d_inode, inode, dentry,
 834                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 835                 if (rc) {
 836                         printk(KERN_ERR "Problem with "
 837                                "ecryptfs_write_inode_size_to_metadata; "
 838                                "rc = [%d]\n", rc);
 839                         goto out_fput;
 840                 }
 841                 /* We are reducing the size of the ecryptfs file, and need to
 842                  * know if we need to reduce the size of the lower file. */
 843                 lower_size_before_truncate =
 844                     upper_size_to_lower_size(crypt_stat, i_size);
 845                 lower_size_after_truncate =
 846                     upper_size_to_lower_size(crypt_stat, new_length);
 847                 if (lower_size_after_truncate < lower_size_before_truncate)
 848                         vmtruncate(lower_dentry->d_inode,
 849                                    lower_size_after_truncate);
 850         }
 851         /* Update the access times */
 852         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 853                 = CURRENT_TIME;
 854         mark_inode_dirty_sync(inode);
 855 out_fput:
 856         rc = ecryptfs_close_lower_file(lower_file);
 857         if (rc)
 858                 printk(KERN_ERR "Error closing lower_file\n");
 859 out_free:
 860         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 861                 kmem_cache_free(ecryptfs_file_info_cache,
 862                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 863 out:
 864         return rc;
 865 }
 866
 867 static int
 868 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 869 {
 870         int rc;
 871
 872         if (nd) {
 873                 struct vfsmount *vfsmnt_save = nd->mnt;
 874                 struct dentry *dentry_save = nd->dentry;
 875
 876                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 877                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 878                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 879                 nd->mnt = vfsmnt_save;
 880                 nd->dentry = dentry_save;
 881         } else
 882                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 883         return rc;
 884 }
 885
 886 /**
 887  * ecryptfs_setattr
 888  * @dentry: dentry handle to the inode to modify
 889  * @ia: Structure with flags of what to change and values
 890  *
 891  * Updates the metadata of an inode. If the update is to the size
 892  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 893  * of both the ecryptfs inode and the lower inode.
 894  *
 895  * All other metadata changes will be passed right to the lower filesystem,
 896  * and we will just update our inode to look like the lower.
 897  */
 898 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 899 {
 900         int rc = 0;
 901         struct dentry *lower_dentry;
 902         struct inode *inode;
 903         struct inode *lower_inode;
 904         struct ecryptfs_crypt_stat *crypt_stat;
 905
 906         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 907         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 908                 ecryptfs_init_crypt_stat(crypt_stat);
 909         inode = dentry->d_inode;
 910         lower_inode = ecryptfs_inode_to_lower(inode);
 911         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 912         mutex_lock(&crypt_stat->cs_mutex);
 913         if (S_ISDIR(dentry->d_inode->i_mode))
 914                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 915         else if (S_ISREG(dentry->d_inode->i_mode)
 916                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 917                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 918                 struct vfsmount *lower_mnt;
 919                 struct file *lower_file = NULL;
 920                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 921                 int lower_flags;
 922
 923                 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 924                 lower_flags = O_RDONLY;
 925                 rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
 926                                               lower_mnt, lower_flags);
 927                 if (rc) {
 928                         printk(KERN_ERR
 929                                "Error opening lower file; rc = [%d]\n", rc);
 930                         mutex_unlock(&crypt_stat->cs_mutex);
 931                         goto out;
 932                 }
 933                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 934                         dentry->d_sb)->mount_crypt_stat;
 935                 rc = ecryptfs_read_metadata(dentry, lower_file);
 936                 if (rc) {
 937                         if (!(mount_crypt_stat->flags
 938                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 939                                 rc = -EIO;
 940                                 printk(KERN_WARNING "Attempt to read file that "
 941                                        "is not in a valid eCryptfs format, "
 942                                        "and plaintext passthrough mode is not "
 943                                        "enabled; returning -EIO\n");
 944
 945                                 mutex_unlock(&crypt_stat->cs_mutex);
 946                                 fput(lower_file);
 947                                 goto out;
 948                         }
 949                         rc = 0;
 950                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 951                         mutex_unlock(&crypt_stat->cs_mutex);
 952                         fput(lower_file);
 953                         goto out;
 954                 }
 955                 fput(lower_file);
 956         }
 957         mutex_unlock(&crypt_stat->cs_mutex);
 958         if (ia->ia_valid & ATTR_SIZE) {
 959                 ecryptfs_printk(KERN_DEBUG,
 960                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 961                                 ia->ia_valid, ATTR_SIZE);
 962                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 963                 /* ecryptfs_truncate handles resizing of the lower file */
 964                 ia->ia_valid &= ~ATTR_SIZE;
 965                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 966                                 ia->ia_valid);
 967                 if (rc < 0)
 968                         goto out;
 969         }
 970         rc = notify_change(lower_dentry, ia);
 971 out:
 972         fsstack_copy_attr_all(inode, lower_inode, NULL);
 973         return rc;
 974 }
 975
 976 int
 977 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 978                   size_t size, int flags)
 979 {
 980         int rc = 0;
 981         struct dentry *lower_dentry;
 982
 983         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 984         if (!lower_dentry->d_inode->i_op->setxattr) {
 985                 rc = -ENOSYS;
 986                 goto out;
 987         }
 988         mutex_lock(&lower_dentry->d_inode->i_mutex);
 989         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 990                                                    size, flags);
 991         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 992 out:
 993         return rc;
 994 }
 995
 996 ssize_t
 997 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 998                   size_t size)
 999 {
1000         int rc = 0;
1001         struct dentry *lower_dentry;
1002
1003         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1004         if (!lower_dentry->d_inode->i_op->getxattr) {
1005                 rc = -ENOSYS;
1006                 goto out;
1007         }
1008         mutex_lock(&lower_dentry->d_inode->i_mutex);
1009         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1010                                                    size);
1011         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1012 out:
1013         return rc;
1014 }
1015
1016 static ssize_t
1017 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1018 {
1019         int rc = 0;
1020         struct dentry *lower_dentry;
1021
1022         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1023         if (!lower_dentry->d_inode->i_op->listxattr) {
1024                 rc = -ENOSYS;
1025                 goto out;
1026         }
1027         mutex_lock(&lower_dentry->d_inode->i_mutex);
1028         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1029         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1030 out:
1031         return rc;
1032 }
1033
1034 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1035 {
1036         int rc = 0;
1037         struct dentry *lower_dentry;
1038
1039         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1040         if (!lower_dentry->d_inode->i_op->removexattr) {
1041                 rc = -ENOSYS;
1042                 goto out;
1043         }
1044         mutex_lock(&lower_dentry->d_inode->i_mutex);
1045         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1046         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1047 out:
1048         return rc;
1049 }
1050
1051 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1052 {
1053         if ((ecryptfs_inode_to_lower(inode)
1054              == (struct inode *)candidate_lower_inode))
1055                 return 1;
1056         else
1057                 return 0;
1058 }
1059
1060 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1061 {
1062         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1063         return 0;
1064 }
1065
1066 const struct inode_operations ecryptfs_symlink_iops = {
1067         .readlink = ecryptfs_readlink,
1068         .follow_link = ecryptfs_follow_link,
1069         .put_link = ecryptfs_put_link,
1070         .permission = ecryptfs_permission,
1071         .setattr = ecryptfs_setattr,
1072         .setxattr = ecryptfs_setxattr,
1073         .getxattr = ecryptfs_getxattr,
1074         .listxattr = ecryptfs_listxattr,
1075         .removexattr = ecryptfs_removexattr
1076 };
1077
1078 const struct inode_operations ecryptfs_dir_iops = {
1079         .create = ecryptfs_create,
1080         .lookup = ecryptfs_lookup,
1081         .link = ecryptfs_link,
1082         .unlink = ecryptfs_unlink,
1083         .symlink = ecryptfs_symlink,
1084         .mkdir = ecryptfs_mkdir,
1085         .rmdir = ecryptfs_rmdir,
1086         .mknod = ecryptfs_mknod,
1087         .rename = ecryptfs_rename,
1088         .permission = ecryptfs_permission,
1089         .setattr = ecryptfs_setattr,
1090         .setxattr = ecryptfs_setxattr,
1091         .getxattr = ecryptfs_getxattr,
1092         .listxattr = ecryptfs_listxattr,
1093         .removexattr = ecryptfs_removexattr
1094 };
1095
1096 const struct inode_operations ecryptfs_main_iops = {
1097         .permission = ecryptfs_permission,
1098         .setattr = ecryptfs_setattr,
1099         .setxattr = ecryptfs_setxattr,
1100         .getxattr = ecryptfs_getxattr,
1101         .listxattr = ecryptfs_listxattr,
1102         .removexattr = ecryptfs_removexattr
1103 };