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(&(dir->d_inode->i_mutex));
  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         ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode, inode,
 172                                               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 #if BITS_PER_LONG != 32
 204         lower_flags |= O_LARGEFILE;
 205 #endif
 206         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 207         /* Corresponding fput() at end of this function */
 208         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 209                                            lower_flags))) {
 210                 ecryptfs_printk(KERN_ERR,
 211                                 "Error opening dentry; rc = [%i]\n", rc);
 212                 goto out;
 213         }
 214         lower_inode = lower_dentry->d_inode;
 215         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 216                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 217                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 218                 goto out_fput;
 219         }
 220         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
 221         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 222         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 223         if (rc) {
 224                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
 225                                 "context\n");
 226                 goto out_fput;
 227         }
 228         rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
 229         if (rc) {
 230                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
 231                 goto out_fput;
 232         }
 233         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
 234 out_fput:
 235         if ((rc = ecryptfs_close_lower_file(lower_file)))
 236                 printk(KERN_ERR "Error closing lower_file\n");
 237 out:
 238         return rc;
 239 }
 240
 241 /**
 242  * ecryptfs_create
 243  * @dir: The inode of the directory in which to create the file.
 244  * @dentry: The eCryptfs dentry
 245  * @mode: The mode of the new file.
 246  * @nd: nameidata
 247  *
 248  * Creates a new file.
 249  *
 250  * Returns zero on success; non-zero on error condition
 251  */
 252 static int
 253 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 254                 int mode, struct nameidata *nd)
 255 {
 256         int rc;
 257
 258         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 259         if (unlikely(rc)) {
 260                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 261                                 "lower filesystem\n");
 262                 goto out;
 263         }
 264         /* At this point, a file exists on "disk"; we need to make sure
 265          * that this on disk file is prepared to be an ecryptfs file */
 266         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 267 out:
 268         return rc;
 269 }
 270
 271 /**
 272  * ecryptfs_lookup
 273  * @dir: inode
 274  * @dentry: The dentry
 275  * @nd: nameidata, may be NULL
 276  *
 277  * Find a file on disk. If the file does not exist, then we'll add it to the
 278  * dentry cache and continue on to read it from the disk.
 279  */
 280 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 281                                       struct nameidata *nd)
 282 {
 283         int rc = 0;
 284         struct dentry *lower_dir_dentry;
 285         struct dentry *lower_dentry;
 286         struct vfsmount *lower_mnt;
 287         char *encoded_name;
 288         unsigned int encoded_namelen;
 289         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 290         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 291         char *page_virt = NULL;
 292         struct inode *lower_inode;
 293         u64 file_size;
 294
 295         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 296         dentry->d_op = &ecryptfs_dops;
 297         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 298             || (dentry->d_name.len == 2
 299                 && !strcmp(dentry->d_name.name, ".."))) {
 300                 d_drop(dentry);
 301                 goto out;
 302         }
 303         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 304                                                    dentry->d_name.name,
 305                                                    dentry->d_name.len,
 306                                                    &encoded_name);
 307         if (encoded_namelen < 0) {
 308                 rc = encoded_namelen;
 309                 d_drop(dentry);
 310                 goto out;
 311         }
 312         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 313                         "= [%d]\n", encoded_name, encoded_namelen);
 314         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 315                                       encoded_namelen - 1);
 316         kfree(encoded_name);
 317         if (IS_ERR(lower_dentry)) {
 318                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 319                 rc = PTR_ERR(lower_dentry);
 320                 d_drop(dentry);
 321                 goto out;
 322         }
 323         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 324         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 325                 "d_name.name = [%s]\n", lower_dentry,
 326                 lower_dentry->d_name.name);
 327         lower_inode = lower_dentry->d_inode;
 328         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 329         BUG_ON(!atomic_read(&lower_dentry->d_count));
 330         ecryptfs_set_dentry_private(dentry,
 331                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 332                                                      GFP_KERNEL));
 333         if (!ecryptfs_dentry_to_private(dentry)) {
 334                 rc = -ENOMEM;
 335                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 336                                 "to allocate ecryptfs_dentry_info struct\n");
 337                 goto out_dput;
 338         }
 339         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 340         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 341         if (!lower_dentry->d_inode) {
 342                 /* We want to add because we couldn't find in lower */
 343                 d_add(dentry, NULL);
 344                 goto out;
 345         }
 346         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 347         if (rc) {
 348                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 349                 goto out_dput;
 350         }
 351         if (S_ISDIR(lower_inode->i_mode)) {
 352                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 353                 goto out;
 354         }
 355         if (S_ISLNK(lower_inode->i_mode)) {
 356                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 357                 goto out;
 358         }
 359         if (!nd) {
 360                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 361                                 "as we *think* we are about to unlink\n");
 362                 goto out;
 363         }
 364         /* Released in this function */
 365         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 366                                       GFP_USER);
 367         if (!page_virt) {
 368                 rc = -ENOMEM;
 369                 ecryptfs_printk(KERN_ERR,
 370                                 "Cannot ecryptfs_kmalloc a page\n");
 371                 goto out_dput;
 372         }
 373         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 374         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 375                 ecryptfs_set_default_sizes(crypt_stat);
 376         rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
 377                                                       nd->mnt);
 378         if (rc) {
 379                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 380                 if (rc) {
 381                         printk(KERN_DEBUG "Valid metadata not found in header "
 382                                "region or xattr region; treating file as "
 383                                "unencrypted\n");
 384                         rc = 0;
 385                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 386                         goto out;
 387                 }
 388                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 389         }
 390         mount_crypt_stat = &ecryptfs_superblock_to_private(
 391                 dentry->d_sb)->mount_crypt_stat;
 392         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 393                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 394                         file_size = (crypt_stat->header_extent_size
 395                                      + i_size_read(lower_dentry->d_inode));
 396                 else
 397                         file_size = i_size_read(lower_dentry->d_inode);
 398         } else {
 399                 memcpy(&file_size, page_virt, sizeof(file_size));
 400                 file_size = be64_to_cpu(file_size);
 401         }
 402         i_size_write(dentry->d_inode, (loff_t)file_size);
 403         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 404         goto out;
 405
 406 out_dput:
 407         dput(lower_dentry);
 408         d_drop(dentry);
 409 out:
 410         return ERR_PTR(rc);
 411 }
 412
 413 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 414                          struct dentry *new_dentry)
 415 {
 416         struct dentry *lower_old_dentry;
 417         struct dentry *lower_new_dentry;
 418         struct dentry *lower_dir_dentry;
 419         u64 file_size_save;
 420         int rc;
 421
 422         file_size_save = i_size_read(old_dentry->d_inode);
 423         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 424         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 425         dget(lower_old_dentry);
 426         dget(lower_new_dentry);
 427         lower_dir_dentry = lock_parent(lower_new_dentry);
 428         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 429                       lower_new_dentry);
 430         if (rc || !lower_new_dentry->d_inode)
 431                 goto out_lock;
 432         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 433         if (rc)
 434                 goto out_lock;
 435         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 436         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 437         old_dentry->d_inode->i_nlink =
 438                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 439         i_size_write(new_dentry->d_inode, file_size_save);
 440 out_lock:
 441         unlock_dir(lower_dir_dentry);
 442         dput(lower_new_dentry);
 443         dput(lower_old_dentry);
 444         d_drop(lower_old_dentry);
 445         d_drop(new_dentry);
 446         d_drop(old_dentry);
 447         return rc;
 448 }
 449
 450 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 451 {
 452         int rc = 0;
 453         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 454         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 455
 456         lock_parent(lower_dentry);
 457         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 458         if (rc) {
 459                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 460                 goto out_unlock;
 461         }
 462         fsstack_copy_attr_times(dir, lower_dir_inode);
 463         dentry->d_inode->i_nlink =
 464                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 465         dentry->d_inode->i_ctime = dir->i_ctime;
 466 out_unlock:
 467         unlock_parent(lower_dentry);
 468         return rc;
 469 }
 470
 471 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 472                             const char *symname)
 473 {
 474         int rc;
 475         struct dentry *lower_dentry;
 476         struct dentry *lower_dir_dentry;
 477         umode_t mode;
 478         char *encoded_symname;
 479         unsigned int encoded_symlen;
 480         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 481
 482         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 483         dget(lower_dentry);
 484         lower_dir_dentry = lock_parent(lower_dentry);
 485         mode = S_IALLUGO;
 486         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 487                                                   strlen(symname),
 488                                                   &encoded_symname);
 489         if (encoded_symlen < 0) {
 490                 rc = encoded_symlen;
 491                 goto out_lock;
 492         }
 493         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 494                          encoded_symname, mode);
 495         kfree(encoded_symname);
 496         if (rc || !lower_dentry->d_inode)
 497                 goto out_lock;
 498         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 499         if (rc)
 500                 goto out_lock;
 501         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 502         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 503 out_lock:
 504         unlock_dir(lower_dir_dentry);
 505         dput(lower_dentry);
 506         if (!dentry->d_inode)
 507                 d_drop(dentry);
 508         return rc;
 509 }
 510
 511 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 512 {
 513         int rc;
 514         struct dentry *lower_dentry;
 515         struct dentry *lower_dir_dentry;
 516
 517         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 518         lower_dir_dentry = lock_parent(lower_dentry);
 519         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 520         if (rc || !lower_dentry->d_inode)
 521                 goto out;
 522         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 523         if (rc)
 524                 goto out;
 525         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 526         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 527         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 528 out:
 529         unlock_dir(lower_dir_dentry);
 530         if (!dentry->d_inode)
 531                 d_drop(dentry);
 532         return rc;
 533 }
 534
 535 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 536 {
 537         struct dentry *lower_dentry;
 538         struct dentry *lower_dir_dentry;
 539         int rc;
 540
 541         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 542         dget(dentry);
 543         lower_dir_dentry = lock_parent(lower_dentry);
 544         dget(lower_dentry);
 545         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 546         dput(lower_dentry);
 547         if (!rc)
 548                 d_delete(lower_dentry);
 549         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 550         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 551         unlock_dir(lower_dir_dentry);
 552         if (!rc)
 553                 d_drop(dentry);
 554         dput(dentry);
 555         return rc;
 556 }
 557
 558 static int
 559 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 560 {
 561         int rc;
 562         struct dentry *lower_dentry;
 563         struct dentry *lower_dir_dentry;
 564
 565         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 566         lower_dir_dentry = lock_parent(lower_dentry);
 567         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 568         if (rc || !lower_dentry->d_inode)
 569                 goto out;
 570         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 571         if (rc)
 572                 goto out;
 573         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 574         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 575 out:
 576         unlock_dir(lower_dir_dentry);
 577         if (!dentry->d_inode)
 578                 d_drop(dentry);
 579         return rc;
 580 }
 581
 582 static int
 583 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 584                 struct inode *new_dir, struct dentry *new_dentry)
 585 {
 586         int rc;
 587         struct dentry *lower_old_dentry;
 588         struct dentry *lower_new_dentry;
 589         struct dentry *lower_old_dir_dentry;
 590         struct dentry *lower_new_dir_dentry;
 591
 592         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 593         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 594         dget(lower_old_dentry);
 595         dget(lower_new_dentry);
 596         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 597         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 598         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 599         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 600                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 601         if (rc)
 602                 goto out_lock;
 603         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 604         if (new_dir != old_dir)
 605                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 606 out_lock:
 607         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 608         dput(lower_new_dentry->d_parent);
 609         dput(lower_old_dentry->d_parent);
 610         dput(lower_new_dentry);
 611         dput(lower_old_dentry);
 612         return rc;
 613 }
 614
 615 static int
 616 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 617 {
 618         int rc;
 619         struct dentry *lower_dentry;
 620         char *decoded_name;
 621         char *lower_buf;
 622         mm_segment_t old_fs;
 623         struct ecryptfs_crypt_stat *crypt_stat;
 624
 625         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 626         if (!lower_dentry->d_inode->i_op ||
 627             !lower_dentry->d_inode->i_op->readlink) {
 628                 rc = -EINVAL;
 629                 goto out;
 630         }
 631         /* Released in this function */
 632         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 633         if (lower_buf == NULL) {
 634                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 635                 rc = -ENOMEM;
 636                 goto out;
 637         }
 638         old_fs = get_fs();
 639         set_fs(get_ds());
 640         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 641                         "lower_dentry->d_name.name = [%s]\n",
 642                         lower_dentry->d_name.name);
 643         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 644                                                    (char __user *)lower_buf,
 645                                                    bufsiz);
 646         set_fs(old_fs);
 647         if (rc >= 0) {
 648                 crypt_stat = NULL;
 649                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 650                                               &decoded_name);
 651                 if (rc == -ENOMEM)
 652                         goto out_free_lower_buf;
 653                 if (rc > 0) {
 654                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 655                                         "to userspace: [%*s]\n", rc,
 656                                         decoded_name);
 657                         if (copy_to_user(buf, decoded_name, rc))
 658                                 rc = -EFAULT;
 659                 }
 660                 kfree(decoded_name);
 661                 fsstack_copy_attr_atime(dentry->d_inode,
 662                                         lower_dentry->d_inode);
 663         }
 664 out_free_lower_buf:
 665         kfree(lower_buf);
 666 out:
 667         return rc;
 668 }
 669
 670 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 671 {
 672         char *buf;
 673         int len = PAGE_SIZE, rc;
 674         mm_segment_t old_fs;
 675
 676         /* Released in ecryptfs_put_link(); only release here on error */
 677         buf = kmalloc(len, GFP_KERNEL);
 678         if (!buf) {
 679                 rc = -ENOMEM;
 680                 goto out;
 681         }
 682         old_fs = get_fs();
 683         set_fs(get_ds());
 684         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 685                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 686         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 687         buf[rc] = '\0';
 688         set_fs(old_fs);
 689         if (rc < 0)
 690                 goto out_free;
 691         rc = 0;
 692         nd_set_link(nd, buf);
 693         goto out;
 694 out_free:
 695         kfree(buf);
 696 out:
 697         return ERR_PTR(rc);
 698 }
 699
 700 static void
 701 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 702 {
 703         /* Free the char* */
 704         kfree(nd_get_link(nd));
 705 }
 706
 707 /**
 708  * upper_size_to_lower_size
 709  * @crypt_stat: Crypt_stat associated with file
 710  * @upper_size: Size of the upper file
 711  *
 712  * Calculate the requried size of the lower file based on the
 713  * specified size of the upper file. This calculation is based on the
 714  * number of headers in the underlying file and the extent size.
 715  *
 716  * Returns Calculated size of the lower file.
 717  */
 718 static loff_t
 719 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 720                          loff_t upper_size)
 721 {
 722         loff_t lower_size;
 723
 724         lower_size = ( crypt_stat->header_extent_size
 725                        * crypt_stat->num_header_extents_at_front );
 726         if (upper_size != 0) {
 727                 loff_t num_extents;
 728
 729                 num_extents = upper_size >> crypt_stat->extent_shift;
 730                 if (upper_size & ~crypt_stat->extent_mask)
 731                         num_extents++;
 732                 lower_size += (num_extents * crypt_stat->extent_size);
 733         }
 734         return lower_size;
 735 }
 736
 737 /**
 738  * ecryptfs_truncate
 739  * @dentry: The ecryptfs layer dentry
 740  * @new_length: The length to expand the file to
 741  *
 742  * Function to handle truncations modifying the size of the file. Note
 743  * that the file sizes are interpolated. When expanding, we are simply
 744  * writing strings of 0's out. When truncating, we need to modify the
 745  * underlying file size according to the page index interpolations.
 746  *
 747  * Returns zero on success; non-zero otherwise
 748  */
 749 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 750 {
 751         int rc = 0;
 752         struct inode *inode = dentry->d_inode;
 753         struct dentry *lower_dentry;
 754         struct vfsmount *lower_mnt;
 755         struct file fake_ecryptfs_file, *lower_file = NULL;
 756         struct ecryptfs_crypt_stat *crypt_stat;
 757         loff_t i_size = i_size_read(inode);
 758         loff_t lower_size_before_truncate;
 759         loff_t lower_size_after_truncate;
 760
 761         if (unlikely((new_length == i_size)))
 762                 goto out;
 763         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 764         /* Set up a fake ecryptfs file, this is used to interface with
 765          * the file in the underlying filesystem so that the
 766          * truncation has an effect there as well. */
 767         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 768         fake_ecryptfs_file.f_path.dentry = dentry;
 769         /* Released at out_free: label */
 770         ecryptfs_set_file_private(&fake_ecryptfs_file,
 771                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 772                                                    GFP_KERNEL));
 773         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 774                 rc = -ENOMEM;
 775                 goto out;
 776         }
 777         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 778         /* This dget & mntget is released through fput at out_fput: */
 779         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 780         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 781                                            O_RDWR))) {
 782                 ecryptfs_printk(KERN_ERR,
 783                                 "Error opening dentry; rc = [%i]\n", rc);
 784                 goto out_free;
 785         }
 786         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 787         /* Switch on growing or shrinking file */
 788         if (new_length > i_size) {
 789                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 790                 if (rc) {
 791                         ecryptfs_printk(KERN_ERR,
 792                                         "Problem with fill_zeros\n");
 793                         goto out_fput;
 794                 }
 795                 i_size_write(inode, new_length);
 796                 rc = ecryptfs_write_inode_size_to_metadata(
 797                         lower_file, lower_dentry->d_inode, inode, dentry,
 798                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 799                 if (rc) {
 800                         printk(KERN_ERR "Problem with "
 801                                "ecryptfs_write_inode_size_to_metadata; "
 802                                "rc = [%d]\n", rc);
 803                         goto out_fput;
 804                 }
 805         } else { /* new_length < i_size_read(inode) */
 806                 vmtruncate(inode, new_length);
 807                 rc = ecryptfs_write_inode_size_to_metadata(
 808                         lower_file, lower_dentry->d_inode, inode, dentry,
 809                         ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
 810                 if (rc) {
 811                         printk(KERN_ERR "Problem with "
 812                                "ecryptfs_write_inode_size_to_metadata; "
 813                                "rc = [%d]\n", rc);
 814                         goto out_fput;
 815                 }
 816                 /* We are reducing the size of the ecryptfs file, and need to
 817                  * know if we need to reduce the size of the lower file. */
 818                 lower_size_before_truncate =
 819                     upper_size_to_lower_size(crypt_stat, i_size);
 820                 lower_size_after_truncate =
 821                     upper_size_to_lower_size(crypt_stat, new_length);
 822                 if (lower_size_after_truncate < lower_size_before_truncate)
 823                         vmtruncate(lower_dentry->d_inode,
 824                                    lower_size_after_truncate);
 825         }
 826         /* Update the access times */
 827         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 828                 = CURRENT_TIME;
 829         mark_inode_dirty_sync(inode);
 830 out_fput:
 831         if ((rc = ecryptfs_close_lower_file(lower_file)))
 832                 printk(KERN_ERR "Error closing lower_file\n");
 833 out_free:
 834         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 835                 kmem_cache_free(ecryptfs_file_info_cache,
 836                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 837 out:
 838         return rc;
 839 }
 840
 841 static int
 842 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 843 {
 844         int rc;
 845
 846         if (nd) {
 847                 struct vfsmount *vfsmnt_save = nd->mnt;
 848                 struct dentry *dentry_save = nd->dentry;
 849
 850                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 851                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 852                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 853                 nd->mnt = vfsmnt_save;
 854                 nd->dentry = dentry_save;
 855         } else
 856                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 857         return rc;
 858 }
 859
 860 /**
 861  * ecryptfs_setattr
 862  * @dentry: dentry handle to the inode to modify
 863  * @ia: Structure with flags of what to change and values
 864  *
 865  * Updates the metadata of an inode. If the update is to the size
 866  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 867  * of both the ecryptfs inode and the lower inode.
 868  *
 869  * All other metadata changes will be passed right to the lower filesystem,
 870  * and we will just update our inode to look like the lower.
 871  */
 872 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 873 {
 874         int rc = 0;
 875         struct dentry *lower_dentry;
 876         struct inode *inode;
 877         struct inode *lower_inode;
 878         struct ecryptfs_crypt_stat *crypt_stat;
 879
 880         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 881         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 882         inode = dentry->d_inode;
 883         lower_inode = ecryptfs_inode_to_lower(inode);
 884         if (ia->ia_valid & ATTR_SIZE) {
 885                 ecryptfs_printk(KERN_DEBUG,
 886                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 887                                 ia->ia_valid, ATTR_SIZE);
 888                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 889                 /* ecryptfs_truncate handles resizing of the lower file */
 890                 ia->ia_valid &= ~ATTR_SIZE;
 891                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 892                                 ia->ia_valid);
 893                 if (rc < 0)
 894                         goto out;
 895         }
 896         rc = notify_change(lower_dentry, ia);
 897 out:
 898         fsstack_copy_attr_all(inode, lower_inode, NULL);
 899         return rc;
 900 }
 901
 902 int
 903 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 904                   size_t size, int flags)
 905 {
 906         int rc = 0;
 907         struct dentry *lower_dentry;
 908
 909         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 910         if (!lower_dentry->d_inode->i_op->setxattr) {
 911                 rc = -ENOSYS;
 912                 goto out;
 913         }
 914         mutex_lock(&lower_dentry->d_inode->i_mutex);
 915         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 916                                                    size, flags);
 917         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 918 out:
 919         return rc;
 920 }
 921
 922 ssize_t
 923 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 924                   size_t size)
 925 {
 926         int rc = 0;
 927         struct dentry *lower_dentry;
 928
 929         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 930         if (!lower_dentry->d_inode->i_op->getxattr) {
 931                 rc = -ENOSYS;
 932                 goto out;
 933         }
 934         mutex_lock(&lower_dentry->d_inode->i_mutex);
 935         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 936                                                    size);
 937         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 938 out:
 939         return rc;
 940 }
 941
 942 static ssize_t
 943 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 944 {
 945         int rc = 0;
 946         struct dentry *lower_dentry;
 947
 948         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 949         if (!lower_dentry->d_inode->i_op->listxattr) {
 950                 rc = -ENOSYS;
 951                 goto out;
 952         }
 953         mutex_lock(&lower_dentry->d_inode->i_mutex);
 954         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
 955         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 956 out:
 957         return rc;
 958 }
 959
 960 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
 961 {
 962         int rc = 0;
 963         struct dentry *lower_dentry;
 964
 965         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 966         if (!lower_dentry->d_inode->i_op->removexattr) {
 967                 rc = -ENOSYS;
 968                 goto out;
 969         }
 970         mutex_lock(&lower_dentry->d_inode->i_mutex);
 971         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
 972         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 973 out:
 974         return rc;
 975 }
 976
 977 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
 978 {
 979         if ((ecryptfs_inode_to_lower(inode)
 980              == (struct inode *)candidate_lower_inode))
 981                 return 1;
 982         else
 983                 return 0;
 984 }
 985
 986 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
 987 {
 988         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
 989         return 0;
 990 }
 991
 992 const struct inode_operations ecryptfs_symlink_iops = {
 993         .readlink = ecryptfs_readlink,
 994         .follow_link = ecryptfs_follow_link,
 995         .put_link = ecryptfs_put_link,
 996         .permission = ecryptfs_permission,
 997         .setattr = ecryptfs_setattr,
 998         .setxattr = ecryptfs_setxattr,
 999         .getxattr = ecryptfs_getxattr,
1000         .listxattr = ecryptfs_listxattr,
1001         .removexattr = ecryptfs_removexattr
1002 };
1003
1004 const struct inode_operations ecryptfs_dir_iops = {
1005         .create = ecryptfs_create,
1006         .lookup = ecryptfs_lookup,
1007         .link = ecryptfs_link,
1008         .unlink = ecryptfs_unlink,
1009         .symlink = ecryptfs_symlink,
1010         .mkdir = ecryptfs_mkdir,
1011         .rmdir = ecryptfs_rmdir,
1012         .mknod = ecryptfs_mknod,
1013         .rename = ecryptfs_rename,
1014         .permission = ecryptfs_permission,
1015         .setattr = ecryptfs_setattr,
1016         .setxattr = ecryptfs_setxattr,
1017         .getxattr = ecryptfs_getxattr,
1018         .listxattr = ecryptfs_listxattr,
1019         .removexattr = ecryptfs_removexattr
1020 };
1021
1022 const struct inode_operations ecryptfs_main_iops = {
1023         .permission = ecryptfs_permission,
1024         .setattr = ecryptfs_setattr,
1025         .setxattr = ecryptfs_setxattr,
1026         .getxattr = ecryptfs_getxattr,
1027         .listxattr = ecryptfs_listxattr,
1028         .removexattr = ecryptfs_removexattr
1029 };