err.no Git - 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 (rc) {
 123                 struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
 124                 struct ecryptfs_inode_info *inode_info =
 125                         ecryptfs_inode_to_private(ecryptfs_inode);
 126
 127                 printk(KERN_WARNING "%s: Error creating underlying file; "
 128                        "rc = [%d]; checking for existing\n", __FUNCTION__, rc);
 129                 if (inode_info) {
 130                         mutex_lock(&inode_info->lower_file_mutex);
 131                         if (!inode_info->lower_file) {
 132                                 mutex_unlock(&inode_info->lower_file_mutex);
 133                                 printk(KERN_ERR "%s: Failure to set underlying "
 134                                        "file; rc = [%d]\n", __FUNCTION__, rc);
 135                                 goto out_lock;
 136                         }
 137                         mutex_unlock(&inode_info->lower_file_mutex);
 138                 }
 139         }
 140         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 141                                 directory_inode->i_sb, 0);
 142         if (rc) {
 143                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 144                 goto out_lock;
 145         }
 146         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
 147         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
 148 out_lock:
 149         unlock_dir(lower_dir_dentry);
 150 out:
 151         return rc;
 152 }
 153
 154 /**
 155  * grow_file
 156  * @ecryptfs_dentry: the ecryptfs dentry
 157  * @lower_file: The lower file
 158  * @inode: The ecryptfs inode
 159  * @lower_inode: The lower inode
 160  *
 161  * This is the code which will grow the file to its correct size.
 162  */
 163 static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
 164                      struct inode *inode, struct inode *lower_inode)
 165 {
 166         int rc = 0;
 167         struct file fake_file;
 168         struct ecryptfs_file_info tmp_file_info;
 169
 170         memset(&fake_file, 0, sizeof(fake_file));
 171         fake_file.f_path.dentry = ecryptfs_dentry;
 172         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 173         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 174         ecryptfs_set_file_lower(&fake_file, lower_file);
 175         rc = ecryptfs_fill_zeros(&fake_file, 1);
 176         if (rc) {
 177                 ecryptfs_inode_to_private(inode)->crypt_stat.flags |=
 178                         ECRYPTFS_SECURITY_WARNING;
 179                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
 180                                 "in file; rc = [%d]\n", rc);
 181                 goto out;
 182         }
 183         i_size_write(inode, 0);
 184         rc = ecryptfs_write_inode_size_to_metadata(inode);
 185         ecryptfs_inode_to_private(inode)->crypt_stat.flags |= ECRYPTFS_NEW_FILE;
 186 out:
 187         return rc;
 188 }
 189
 190 /**
 191  * ecryptfs_initialize_file
 192  *
 193  * Cause the file to be changed from a basic empty file to an ecryptfs
 194  * file with a header and first data page.
 195  *
 196  * Returns zero on success
 197  */
 198 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 199 {
 200         int rc = 0;
 201         int lower_flags;
 202         struct ecryptfs_crypt_stat *crypt_stat;
 203         struct dentry *lower_dentry;
 204         struct file *lower_file;
 205         struct inode *inode, *lower_inode;
 206         struct vfsmount *lower_mnt;
 207
 208         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 209         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
 210                         lower_dentry->d_name.name);
 211         inode = ecryptfs_dentry->d_inode;
 212         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 213         lower_flags = ((O_CREAT | O_TRUNC) & O_ACCMODE) | O_RDWR;
 214         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 215         /* Corresponding fput() at end of this function */
 216         rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 217                                       lower_flags);
 218         if (rc) {
 219                 ecryptfs_printk(KERN_ERR,
 220                                 "Error opening dentry; rc = [%i]\n", rc);
 221                 goto out;
 222         }
 223         lower_inode = lower_dentry->d_inode;
 224         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 225                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 226                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 227                 goto out_fput;
 228         }
 229         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
 230         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 231         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 232         if (rc) {
 233                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
 234                                 "context\n");
 235                 goto out_fput;
 236         }
 237         rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
 238         if (rc) {
 239                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
 240                 goto out_fput;
 241         }
 242         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
 243 out_fput:
 244         rc = ecryptfs_close_lower_file(lower_file);
 245         if (rc)
 246                 printk(KERN_ERR "Error closing lower_file\n");
 247 out:
 248         return rc;
 249 }
 250
 251 /**
 252  * ecryptfs_create
 253  * @dir: The inode of the directory in which to create the file.
 254  * @dentry: The eCryptfs dentry
 255  * @mode: The mode of the new file.
 256  * @nd: nameidata
 257  *
 258  * Creates a new file.
 259  *
 260  * Returns zero on success; non-zero on error condition
 261  */
 262 static int
 263 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 264                 int mode, struct nameidata *nd)
 265 {
 266         int rc;
 267
 268         /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
 269          * the crypt_stat->lower_file (persistent file) */
 270         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 271         if (unlikely(rc)) {
 272                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 273                                 "lower filesystem\n");
 274                 goto out;
 275         }
 276         /* At this point, a file exists on "disk"; we need to make sure
 277          * that this on disk file is prepared to be an ecryptfs file */
 278         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 279 out:
 280         return rc;
 281 }
 282
 283 /**
 284  * ecryptfs_lookup
 285  * @dir: inode
 286  * @dentry: The dentry
 287  * @nd: nameidata, may be NULL
 288  *
 289  * Find a file on disk. If the file does not exist, then we'll add it to the
 290  * dentry cache and continue on to read it from the disk.
 291  */
 292 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 293                                       struct nameidata *nd)
 294 {
 295         int rc = 0;
 296         struct dentry *lower_dir_dentry;
 297         struct dentry *lower_dentry;
 298         struct vfsmount *lower_mnt;
 299         char *encoded_name;
 300         int encoded_namelen;
 301         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 302         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 303         char *page_virt = NULL;
 304         struct inode *lower_inode;
 305         u64 file_size;
 306
 307         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 308         dentry->d_op = &ecryptfs_dops;
 309         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 310             || (dentry->d_name.len == 2
 311                 && !strcmp(dentry->d_name.name, ".."))) {
 312                 d_drop(dentry);
 313                 goto out;
 314         }
 315         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 316                                                    dentry->d_name.name,
 317                                                    dentry->d_name.len,
 318                                                    &encoded_name);
 319         if (encoded_namelen < 0) {
 320                 rc = encoded_namelen;
 321                 d_drop(dentry);
 322                 goto out;
 323         }
 324         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 325                         "= [%d]\n", encoded_name, encoded_namelen);
 326         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 327                                       encoded_namelen - 1);
 328         kfree(encoded_name);
 329         if (IS_ERR(lower_dentry)) {
 330                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 331                 rc = PTR_ERR(lower_dentry);
 332                 d_drop(dentry);
 333                 goto out;
 334         }
 335         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 336         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 337                 "d_name.name = [%s]\n", lower_dentry,
 338                 lower_dentry->d_name.name);
 339         lower_inode = lower_dentry->d_inode;
 340         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 341         BUG_ON(!atomic_read(&lower_dentry->d_count));
 342         ecryptfs_set_dentry_private(dentry,
 343                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 344                                                      GFP_KERNEL));
 345         if (!ecryptfs_dentry_to_private(dentry)) {
 346                 rc = -ENOMEM;
 347                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 348                                 "to allocate ecryptfs_dentry_info struct\n");
 349                 goto out_dput;
 350         }
 351         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 352         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 353         if (!lower_dentry->d_inode) {
 354                 /* We want to add because we couldn't find in lower */
 355                 d_add(dentry, NULL);
 356                 goto out;
 357         }
 358         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 359         if (rc) {
 360                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 361                 goto out_dput;
 362         }
 363         if (S_ISDIR(lower_inode->i_mode)) {
 364                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 365                 goto out;
 366         }
 367         if (S_ISLNK(lower_inode->i_mode)) {
 368                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 369                 goto out;
 370         }
 371         if (special_file(lower_inode->i_mode)) {
 372                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
 373                 goto out;
 374         }
 375         if (!nd) {
 376                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 377                                 "as we *think* we are about to unlink\n");
 378                 goto out;
 379         }
 380         /* Released in this function */
 381         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 382                                       GFP_USER);
 383         if (!page_virt) {
 384                 rc = -ENOMEM;
 385                 ecryptfs_printk(KERN_ERR,
 386                                 "Cannot ecryptfs_kmalloc a page\n");
 387                 goto out_dput;
 388         }
 389         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 390         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 391                 ecryptfs_set_default_sizes(crypt_stat);
 392         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
 393                                                       nd->mnt);
 394         if (rc) {
 395                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 396                 if (rc) {
 397                         printk(KERN_DEBUG "Valid metadata not found in header "
 398                                "region or xattr region; treating file as "
 399                                "unencrypted\n");
 400                         rc = 0;
 401                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 402                         goto out;
 403                 }
 404                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 405         }
 406         mount_crypt_stat = &ecryptfs_superblock_to_private(
 407                 dentry->d_sb)->mount_crypt_stat;
 408         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 409                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 410                         file_size = ((crypt_stat->extent_size
 411                                       * crypt_stat->num_header_extents_at_front)
 412                                      + i_size_read(lower_dentry->d_inode));
 413                 else
 414                         file_size = i_size_read(lower_dentry->d_inode);
 415         } else {
 416                 memcpy(&file_size, page_virt, sizeof(file_size));
 417                 file_size = be64_to_cpu(file_size);
 418         }
 419         i_size_write(dentry->d_inode, (loff_t)file_size);
 420         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 421         goto out;
 422
 423 out_dput:
 424         dput(lower_dentry);
 425         d_drop(dentry);
 426 out:
 427         return ERR_PTR(rc);
 428 }
 429
 430 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 431                          struct dentry *new_dentry)
 432 {
 433         struct dentry *lower_old_dentry;
 434         struct dentry *lower_new_dentry;
 435         struct dentry *lower_dir_dentry;
 436         u64 file_size_save;
 437         int rc;
 438
 439         file_size_save = i_size_read(old_dentry->d_inode);
 440         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 441         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 442         dget(lower_old_dentry);
 443         dget(lower_new_dentry);
 444         lower_dir_dentry = lock_parent(lower_new_dentry);
 445         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 446                       lower_new_dentry);
 447         if (rc || !lower_new_dentry->d_inode)
 448                 goto out_lock;
 449         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 450         if (rc)
 451                 goto out_lock;
 452         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 453         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 454         old_dentry->d_inode->i_nlink =
 455                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 456         i_size_write(new_dentry->d_inode, file_size_save);
 457 out_lock:
 458         unlock_dir(lower_dir_dentry);
 459         dput(lower_new_dentry);
 460         dput(lower_old_dentry);
 461         d_drop(lower_old_dentry);
 462         d_drop(new_dentry);
 463         d_drop(old_dentry);
 464         return rc;
 465 }
 466
 467 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 468 {
 469         int rc = 0;
 470         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 471         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 472
 473         lock_parent(lower_dentry);
 474         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 475         if (rc) {
 476                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 477                 goto out_unlock;
 478         }
 479         fsstack_copy_attr_times(dir, lower_dir_inode);
 480         dentry->d_inode->i_nlink =
 481                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 482         dentry->d_inode->i_ctime = dir->i_ctime;
 483 out_unlock:
 484         unlock_parent(lower_dentry);
 485         return rc;
 486 }
 487
 488 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 489                             const char *symname)
 490 {
 491         int rc;
 492         struct dentry *lower_dentry;
 493         struct dentry *lower_dir_dentry;
 494         umode_t mode;
 495         char *encoded_symname;
 496         int encoded_symlen;
 497         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 498
 499         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 500         dget(lower_dentry);
 501         lower_dir_dentry = lock_parent(lower_dentry);
 502         mode = S_IALLUGO;
 503         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 504                                                   strlen(symname),
 505                                                   &encoded_symname);
 506         if (encoded_symlen < 0) {
 507                 rc = encoded_symlen;
 508                 goto out_lock;
 509         }
 510         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 511                          encoded_symname, mode);
 512         kfree(encoded_symname);
 513         if (rc || !lower_dentry->d_inode)
 514                 goto out_lock;
 515         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 516         if (rc)
 517                 goto out_lock;
 518         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 519         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 520 out_lock:
 521         unlock_dir(lower_dir_dentry);
 522         dput(lower_dentry);
 523         if (!dentry->d_inode)
 524                 d_drop(dentry);
 525         return rc;
 526 }
 527
 528 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 529 {
 530         int rc;
 531         struct dentry *lower_dentry;
 532         struct dentry *lower_dir_dentry;
 533
 534         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 535         lower_dir_dentry = lock_parent(lower_dentry);
 536         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 537         if (rc || !lower_dentry->d_inode)
 538                 goto out;
 539         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 540         if (rc)
 541                 goto out;
 542         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 543         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 544         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 545 out:
 546         unlock_dir(lower_dir_dentry);
 547         if (!dentry->d_inode)
 548                 d_drop(dentry);
 549         return rc;
 550 }
 551
 552 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 553 {
 554         struct dentry *lower_dentry;
 555         struct dentry *lower_dir_dentry;
 556         int rc;
 557
 558         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 559         dget(dentry);
 560         lower_dir_dentry = lock_parent(lower_dentry);
 561         dget(lower_dentry);
 562         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 563         dput(lower_dentry);
 564         if (!rc)
 565                 d_delete(lower_dentry);
 566         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 567         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 568         unlock_dir(lower_dir_dentry);
 569         if (!rc)
 570                 d_drop(dentry);
 571         dput(dentry);
 572         return rc;
 573 }
 574
 575 static int
 576 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 577 {
 578         int rc;
 579         struct dentry *lower_dentry;
 580         struct dentry *lower_dir_dentry;
 581
 582         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 583         lower_dir_dentry = lock_parent(lower_dentry);
 584         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 585         if (rc || !lower_dentry->d_inode)
 586                 goto out;
 587         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 588         if (rc)
 589                 goto out;
 590         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 591         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 592 out:
 593         unlock_dir(lower_dir_dentry);
 594         if (!dentry->d_inode)
 595                 d_drop(dentry);
 596         return rc;
 597 }
 598
 599 static int
 600 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 601                 struct inode *new_dir, struct dentry *new_dentry)
 602 {
 603         int rc;
 604         struct dentry *lower_old_dentry;
 605         struct dentry *lower_new_dentry;
 606         struct dentry *lower_old_dir_dentry;
 607         struct dentry *lower_new_dir_dentry;
 608
 609         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 610         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 611         dget(lower_old_dentry);
 612         dget(lower_new_dentry);
 613         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 614         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 615         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 616         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 617                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 618         if (rc)
 619                 goto out_lock;
 620         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 621         if (new_dir != old_dir)
 622                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 623 out_lock:
 624         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 625         dput(lower_new_dentry->d_parent);
 626         dput(lower_old_dentry->d_parent);
 627         dput(lower_new_dentry);
 628         dput(lower_old_dentry);
 629         return rc;
 630 }
 631
 632 static int
 633 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 634 {
 635         int rc;
 636         struct dentry *lower_dentry;
 637         char *decoded_name;
 638         char *lower_buf;
 639         mm_segment_t old_fs;
 640         struct ecryptfs_crypt_stat *crypt_stat;
 641
 642         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 643         if (!lower_dentry->d_inode->i_op ||
 644             !lower_dentry->d_inode->i_op->readlink) {
 645                 rc = -EINVAL;
 646                 goto out;
 647         }
 648         /* Released in this function */
 649         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 650         if (lower_buf == NULL) {
 651                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 652                 rc = -ENOMEM;
 653                 goto out;
 654         }
 655         old_fs = get_fs();
 656         set_fs(get_ds());
 657         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 658                         "lower_dentry->d_name.name = [%s]\n",
 659                         lower_dentry->d_name.name);
 660         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 661                                                    (char __user *)lower_buf,
 662                                                    bufsiz);
 663         set_fs(old_fs);
 664         if (rc >= 0) {
 665                 crypt_stat = NULL;
 666                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 667                                               &decoded_name);
 668                 if (rc == -ENOMEM)
 669                         goto out_free_lower_buf;
 670                 if (rc > 0) {
 671                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 672                                         "to userspace: [%*s]\n", rc,
 673                                         decoded_name);
 674                         if (copy_to_user(buf, decoded_name, rc))
 675                                 rc = -EFAULT;
 676                 }
 677                 kfree(decoded_name);
 678                 fsstack_copy_attr_atime(dentry->d_inode,
 679                                         lower_dentry->d_inode);
 680         }
 681 out_free_lower_buf:
 682         kfree(lower_buf);
 683 out:
 684         return rc;
 685 }
 686
 687 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 688 {
 689         char *buf;
 690         int len = PAGE_SIZE, rc;
 691         mm_segment_t old_fs;
 692
 693         /* Released in ecryptfs_put_link(); only release here on error */
 694         buf = kmalloc(len, GFP_KERNEL);
 695         if (!buf) {
 696                 rc = -ENOMEM;
 697                 goto out;
 698         }
 699         old_fs = get_fs();
 700         set_fs(get_ds());
 701         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 702                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 703         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 704         buf[rc] = '\0';
 705         set_fs(old_fs);
 706         if (rc < 0)
 707                 goto out_free;
 708         rc = 0;
 709         nd_set_link(nd, buf);
 710         goto out;
 711 out_free:
 712         kfree(buf);
 713 out:
 714         return ERR_PTR(rc);
 715 }
 716
 717 static void
 718 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 719 {
 720         /* Free the char* */
 721         kfree(nd_get_link(nd));
 722 }
 723
 724 /**
 725  * upper_size_to_lower_size
 726  * @crypt_stat: Crypt_stat associated with file
 727  * @upper_size: Size of the upper file
 728  *
 729  * Calculate the requried size of the lower file based on the
 730  * specified size of the upper file. This calculation is based on the
 731  * number of headers in the underlying file and the extent size.
 732  *
 733  * Returns Calculated size of the lower file.
 734  */
 735 static loff_t
 736 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 737                          loff_t upper_size)
 738 {
 739         loff_t lower_size;
 740
 741         lower_size = (crypt_stat->extent_size
 742                       * crypt_stat->num_header_extents_at_front);
 743         if (upper_size != 0) {
 744                 loff_t num_extents;
 745
 746                 num_extents = upper_size >> crypt_stat->extent_shift;
 747                 if (upper_size & ~crypt_stat->extent_mask)
 748                         num_extents++;
 749                 lower_size += (num_extents * crypt_stat->extent_size);
 750         }
 751         return lower_size;
 752 }
 753
 754 /**
 755  * ecryptfs_truncate
 756  * @dentry: The ecryptfs layer dentry
 757  * @new_length: The length to expand the file to
 758  *
 759  * Function to handle truncations modifying the size of the file. Note
 760  * that the file sizes are interpolated. When expanding, we are simply
 761  * writing strings of 0's out. When truncating, we need to modify the
 762  * underlying file size according to the page index interpolations.
 763  *
 764  * Returns zero on success; non-zero otherwise
 765  */
 766 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 767 {
 768         int rc = 0;
 769         struct inode *inode = dentry->d_inode;
 770         struct dentry *lower_dentry;
 771         struct vfsmount *lower_mnt;
 772         struct file fake_ecryptfs_file, *lower_file = NULL;
 773         struct ecryptfs_crypt_stat *crypt_stat;
 774         loff_t i_size = i_size_read(inode);
 775         loff_t lower_size_before_truncate;
 776         loff_t lower_size_after_truncate;
 777
 778         if (unlikely((new_length == i_size)))
 779                 goto out;
 780         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 781         /* Set up a fake ecryptfs file, this is used to interface with
 782          * the file in the underlying filesystem so that the
 783          * truncation has an effect there as well. */
 784         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 785         fake_ecryptfs_file.f_path.dentry = dentry;
 786         /* Released at out_free: label */
 787         ecryptfs_set_file_private(&fake_ecryptfs_file,
 788                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 789                                                    GFP_KERNEL));
 790         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 791                 rc = -ENOMEM;
 792                 goto out;
 793         }
 794         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 795         /* This dget & mntget is released through fput at out_fput: */
 796         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 797         rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 798                                       O_RDWR);
 799         if (rc) {
 800                 ecryptfs_printk(KERN_ERR,
 801                                 "Error opening dentry; rc = [%i]\n", rc);
 802                 goto out_free;
 803         }
 804         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 805         /* Switch on growing or shrinking file */
 806         if (new_length > i_size) {
 807                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 808                 if (rc) {
 809                         ecryptfs_printk(KERN_ERR,
 810                                         "Problem with fill_zeros\n");
 811                         goto out_fput;
 812                 }
 813                 i_size_write(inode, new_length);
 814                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 815                 if (rc) {
 816                         printk(KERN_ERR "Problem with "
 817                                "ecryptfs_write_inode_size_to_metadata; "
 818                                "rc = [%d]\n", rc);
 819                         goto out_fput;
 820                 }
 821         } else { /* new_length < i_size_read(inode) */
 822                 pgoff_t index = 0;
 823                 int end_pos_in_page = -1;
 824
 825                 if (new_length != 0) {
 826                         index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
 827                         end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
 828                 }
 829                 if (end_pos_in_page != (PAGE_CACHE_SIZE - 1)) {
 830                         rc = ecryptfs_write_zeros(&fake_ecryptfs_file,
 831                                                   index,
 832                                                   (end_pos_in_page + 1),
 833                                                   ((PAGE_CACHE_SIZE - 1)
 834                                                    - end_pos_in_page));
 835                         if (rc) {
 836                                 printk(KERN_ERR "Error attempting to zero out "
 837                                        "the remainder of the end page on "
 838                                        "reducing truncate; rc = [%d]\n", rc);
 839                                 goto out_fput;
 840                         }
 841                 }
 842                 vmtruncate(inode, new_length);
 843                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 844                 if (rc) {
 845                         printk(KERN_ERR "Problem with "
 846                                "ecryptfs_write_inode_size_to_metadata; "
 847                                "rc = [%d]\n", rc);
 848                         goto out_fput;
 849                 }
 850                 /* We are reducing the size of the ecryptfs file, and need to
 851                  * know if we need to reduce the size of the lower file. */
 852                 lower_size_before_truncate =
 853                     upper_size_to_lower_size(crypt_stat, i_size);
 854                 lower_size_after_truncate =
 855                     upper_size_to_lower_size(crypt_stat, new_length);
 856                 if (lower_size_after_truncate < lower_size_before_truncate)
 857                         vmtruncate(lower_dentry->d_inode,
 858                                    lower_size_after_truncate);
 859         }
 860         /* Update the access times */
 861         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 862                 = CURRENT_TIME;
 863         mark_inode_dirty_sync(inode);
 864 out_fput:
 865         rc = ecryptfs_close_lower_file(lower_file);
 866         if (rc)
 867                 printk(KERN_ERR "Error closing lower_file\n");
 868 out_free:
 869         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 870                 kmem_cache_free(ecryptfs_file_info_cache,
 871                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 872 out:
 873         return rc;
 874 }
 875
 876 static int
 877 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 878 {
 879         int rc;
 880
 881         if (nd) {
 882                 struct vfsmount *vfsmnt_save = nd->mnt;
 883                 struct dentry *dentry_save = nd->dentry;
 884
 885                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 886                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 887                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 888                 nd->mnt = vfsmnt_save;
 889                 nd->dentry = dentry_save;
 890         } else
 891                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 892         return rc;
 893 }
 894
 895 /**
 896  * ecryptfs_setattr
 897  * @dentry: dentry handle to the inode to modify
 898  * @ia: Structure with flags of what to change and values
 899  *
 900  * Updates the metadata of an inode. If the update is to the size
 901  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 902  * of both the ecryptfs inode and the lower inode.
 903  *
 904  * All other metadata changes will be passed right to the lower filesystem,
 905  * and we will just update our inode to look like the lower.
 906  */
 907 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 908 {
 909         int rc = 0;
 910         struct dentry *lower_dentry;
 911         struct inode *inode;
 912         struct inode *lower_inode;
 913         struct ecryptfs_crypt_stat *crypt_stat;
 914
 915         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 916         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 917                 ecryptfs_init_crypt_stat(crypt_stat);
 918         inode = dentry->d_inode;
 919         lower_inode = ecryptfs_inode_to_lower(inode);
 920         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 921         mutex_lock(&crypt_stat->cs_mutex);
 922         if (S_ISDIR(dentry->d_inode->i_mode))
 923                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 924         else if (S_ISREG(dentry->d_inode->i_mode)
 925                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 926                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 927                 struct vfsmount *lower_mnt;
 928                 struct file *lower_file = NULL;
 929                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 930                 int lower_flags;
 931
 932                 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 933                 lower_flags = O_RDONLY;
 934                 rc = ecryptfs_open_lower_file(&lower_file, lower_dentry,
 935                                               lower_mnt, lower_flags);
 936                 if (rc) {
 937                         printk(KERN_ERR
 938                                "Error opening lower file; rc = [%d]\n", rc);
 939                         mutex_unlock(&crypt_stat->cs_mutex);
 940                         goto out;
 941                 }
 942                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 943                         dentry->d_sb)->mount_crypt_stat;
 944                 rc = ecryptfs_read_metadata(dentry, lower_file);
 945                 if (rc) {
 946                         if (!(mount_crypt_stat->flags
 947                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 948                                 rc = -EIO;
 949                                 printk(KERN_WARNING "Attempt to read file that "
 950                                        "is not in a valid eCryptfs format, "
 951                                        "and plaintext passthrough mode is not "
 952                                        "enabled; returning -EIO\n");
 953
 954                                 mutex_unlock(&crypt_stat->cs_mutex);
 955                                 fput(lower_file);
 956                                 goto out;
 957                         }
 958                         rc = 0;
 959                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 960                         mutex_unlock(&crypt_stat->cs_mutex);
 961                         fput(lower_file);
 962                         goto out;
 963                 }
 964                 fput(lower_file);
 965         }
 966         mutex_unlock(&crypt_stat->cs_mutex);
 967         if (ia->ia_valid & ATTR_SIZE) {
 968                 ecryptfs_printk(KERN_DEBUG,
 969                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 970                                 ia->ia_valid, ATTR_SIZE);
 971                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 972                 /* ecryptfs_truncate handles resizing of the lower file */
 973                 ia->ia_valid &= ~ATTR_SIZE;
 974                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 975                                 ia->ia_valid);
 976                 if (rc < 0)
 977                         goto out;
 978         }
 979         rc = notify_change(lower_dentry, ia);
 980 out:
 981         fsstack_copy_attr_all(inode, lower_inode, NULL);
 982         return rc;
 983 }
 984
 985 int
 986 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 987                   size_t size, int flags)
 988 {
 989         int rc = 0;
 990         struct dentry *lower_dentry;
 991
 992         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 993         if (!lower_dentry->d_inode->i_op->setxattr) {
 994                 rc = -ENOSYS;
 995                 goto out;
 996         }
 997         mutex_lock(&lower_dentry->d_inode->i_mutex);
 998         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 999                                                    size, flags);
1000         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1001 out:
1002         return rc;
1003 }
1004
1005 ssize_t
1006 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1007                   size_t size)
1008 {
1009         int rc = 0;
1010         struct dentry *lower_dentry;
1011
1012         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1013         if (!lower_dentry->d_inode->i_op->getxattr) {
1014                 rc = -ENOSYS;
1015                 goto out;
1016         }
1017         mutex_lock(&lower_dentry->d_inode->i_mutex);
1018         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1019                                                    size);
1020         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1021 out:
1022         return rc;
1023 }
1024
1025 static ssize_t
1026 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1027 {
1028         int rc = 0;
1029         struct dentry *lower_dentry;
1030
1031         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1032         if (!lower_dentry->d_inode->i_op->listxattr) {
1033                 rc = -ENOSYS;
1034                 goto out;
1035         }
1036         mutex_lock(&lower_dentry->d_inode->i_mutex);
1037         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1038         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1039 out:
1040         return rc;
1041 }
1042
1043 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1044 {
1045         int rc = 0;
1046         struct dentry *lower_dentry;
1047
1048         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1049         if (!lower_dentry->d_inode->i_op->removexattr) {
1050                 rc = -ENOSYS;
1051                 goto out;
1052         }
1053         mutex_lock(&lower_dentry->d_inode->i_mutex);
1054         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1055         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1056 out:
1057         return rc;
1058 }
1059
1060 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1061 {
1062         if ((ecryptfs_inode_to_lower(inode)
1063              == (struct inode *)candidate_lower_inode))
1064                 return 1;
1065         else
1066                 return 0;
1067 }
1068
1069 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1070 {
1071         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1072         return 0;
1073 }
1074
1075 const struct inode_operations ecryptfs_symlink_iops = {
1076         .readlink = ecryptfs_readlink,
1077         .follow_link = ecryptfs_follow_link,
1078         .put_link = ecryptfs_put_link,
1079         .permission = ecryptfs_permission,
1080         .setattr = ecryptfs_setattr,
1081         .setxattr = ecryptfs_setxattr,
1082         .getxattr = ecryptfs_getxattr,
1083         .listxattr = ecryptfs_listxattr,
1084         .removexattr = ecryptfs_removexattr
1085 };
1086
1087 const struct inode_operations ecryptfs_dir_iops = {
1088         .create = ecryptfs_create,
1089         .lookup = ecryptfs_lookup,
1090         .link = ecryptfs_link,
1091         .unlink = ecryptfs_unlink,
1092         .symlink = ecryptfs_symlink,
1093         .mkdir = ecryptfs_mkdir,
1094         .rmdir = ecryptfs_rmdir,
1095         .mknod = ecryptfs_mknod,
1096         .rename = ecryptfs_rename,
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 };
1104
1105 const struct inode_operations ecryptfs_main_iops = {
1106         .permission = ecryptfs_permission,
1107         .setattr = ecryptfs_setattr,
1108         .setxattr = ecryptfs_setxattr,
1109         .getxattr = ecryptfs_getxattr,
1110         .listxattr = ecryptfs_listxattr,
1111         .removexattr = ecryptfs_removexattr
1112 };