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) 2004-2006 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 "ecryptfs_kernel.h"
  34
  35 static struct dentry *lock_parent(struct dentry *dentry)
  36 {
  37         struct dentry *dir;
  38
  39         dir = dget(dentry->d_parent);
  40         mutex_lock(&(dir->d_inode->i_mutex));
  41         return dir;
  42 }
  43
  44 static void unlock_parent(struct dentry *dentry)
  45 {
  46         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
  47         dput(dentry->d_parent);
  48 }
  49
  50 static void unlock_dir(struct dentry *dir)
  51 {
  52         mutex_unlock(&dir->d_inode->i_mutex);
  53         dput(dir);
  54 }
  55
  56 void ecryptfs_copy_inode_size(struct inode *dst, const struct inode *src)
  57 {
  58         i_size_write(dst, i_size_read((struct inode *)src));
  59         dst->i_blocks = src->i_blocks;
  60 }
  61
  62 void ecryptfs_copy_attr_atime(struct inode *dest, const struct inode *src)
  63 {
  64         dest->i_atime = src->i_atime;
  65 }
  66
  67 static void ecryptfs_copy_attr_times(struct inode *dest,
  68                                      const struct inode *src)
  69 {
  70         dest->i_atime = src->i_atime;
  71         dest->i_mtime = src->i_mtime;
  72         dest->i_ctime = src->i_ctime;
  73 }
  74
  75 static void ecryptfs_copy_attr_timesizes(struct inode *dest,
  76                                          const struct inode *src)
  77 {
  78         dest->i_atime = src->i_atime;
  79         dest->i_mtime = src->i_mtime;
  80         dest->i_ctime = src->i_ctime;
  81         ecryptfs_copy_inode_size(dest, src);
  82 }
  83
  84 void ecryptfs_copy_attr_all(struct inode *dest, const struct inode *src)
  85 {
  86         dest->i_mode = src->i_mode;
  87         dest->i_nlink = src->i_nlink;
  88         dest->i_uid = src->i_uid;
  89         dest->i_gid = src->i_gid;
  90         dest->i_rdev = src->i_rdev;
  91         dest->i_atime = src->i_atime;
  92         dest->i_mtime = src->i_mtime;
  93         dest->i_ctime = src->i_ctime;
  94         dest->i_blkbits = src->i_blkbits;
  95         dest->i_flags = src->i_flags;
  96 }
  97
  98 /**
  99  * ecryptfs_create_underlying_file
 100  * @lower_dir_inode: inode of the parent in the lower fs of the new file
 101  * @lower_dentry: New file's dentry in the lower fs
 102  * @ecryptfs_dentry: New file's dentry in ecryptfs
 103  * @mode: The mode of the new file
 104  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 105  *
 106  * Creates the file in the lower file system.
 107  *
 108  * Returns zero on success; non-zero on error condition
 109  */
 110 static int
 111 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
 112                                 struct dentry *dentry, int mode,
 113                                 struct nameidata *nd)
 114 {
 115         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 116         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 117         struct dentry *dentry_save;
 118         struct vfsmount *vfsmount_save;
 119         int rc;
 120
 121         dentry_save = nd->dentry;
 122         vfsmount_save = nd->mnt;
 123         nd->dentry = lower_dentry;
 124         nd->mnt = lower_mnt;
 125         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
 126         nd->dentry = dentry_save;
 127         nd->mnt = vfsmount_save;
 128         return rc;
 129 }
 130
 131 /**
 132  * ecryptfs_do_create
 133  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 134  * @ecryptfs_dentry: New file's dentry in ecryptfs
 135  * @mode: The mode of the new file
 136  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 137  *
 138  * Creates the underlying file and the eCryptfs inode which will link to
 139  * it. It will also update the eCryptfs directory inode to mimic the
 140  * stat of the lower directory inode.
 141  *
 142  * Returns zero on success; non-zero on error condition
 143  */
 144 static int
 145 ecryptfs_do_create(struct inode *directory_inode,
 146                    struct dentry *ecryptfs_dentry, int mode,
 147                    struct nameidata *nd)
 148 {
 149         int rc;
 150         struct dentry *lower_dentry;
 151         struct dentry *lower_dir_dentry;
 152
 153         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 154         lower_dir_dentry = lock_parent(lower_dentry);
 155         if (unlikely(IS_ERR(lower_dir_dentry))) {
 156                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 157                                 "dentry\n");
 158                 rc = PTR_ERR(lower_dir_dentry);
 159                 goto out;
 160         }
 161         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 162                                              ecryptfs_dentry, mode, nd);
 163         if (unlikely(rc)) {
 164                 ecryptfs_printk(KERN_ERR,
 165                                 "Failure to create underlying file\n");
 166                 goto out_lock;
 167         }
 168         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
 169                                 directory_inode->i_sb, 0);
 170         if (rc) {
 171                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
 172                 goto out_lock;
 173         }
 174         ecryptfs_copy_attr_timesizes(directory_inode,
 175                                      lower_dir_dentry->d_inode);
 176 out_lock:
 177         unlock_dir(lower_dir_dentry);
 178 out:
 179         return rc;
 180 }
 181
 182 /**
 183  * grow_file
 184  * @ecryptfs_dentry: the ecryptfs dentry
 185  * @lower_file: The lower file
 186  * @inode: The ecryptfs inode
 187  * @lower_inode: The lower inode
 188  *
 189  * This is the code which will grow the file to its correct size.
 190  */
 191 static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
 192                      struct inode *inode, struct inode *lower_inode)
 193 {
 194         int rc = 0;
 195         struct file fake_file;
 196         struct ecryptfs_file_info tmp_file_info;
 197
 198         memset(&fake_file, 0, sizeof(fake_file));
 199         fake_file.f_dentry = ecryptfs_dentry;
 200         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 201         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 202         ecryptfs_set_file_lower(&fake_file, lower_file);
 203         rc = ecryptfs_fill_zeros(&fake_file, 1);
 204         if (rc) {
 205                 ECRYPTFS_SET_FLAG(
 206                         ecryptfs_inode_to_private(inode)->crypt_stat.flags,
 207                         ECRYPTFS_SECURITY_WARNING);
 208                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
 209                                 "in file; rc = [%d]\n", rc);
 210                 goto out;
 211         }
 212         i_size_write(inode, 0);
 213         ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
 214         ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
 215                           ECRYPTFS_NEW_FILE);
 216 out:
 217         return rc;
 218 }
 219
 220 /**
 221  * ecryptfs_initialize_file
 222  *
 223  * Cause the file to be changed from a basic empty file to an ecryptfs
 224  * file with a header and first data page.
 225  *
 226  * Returns zero on success
 227  */
 228 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 229 {
 230         int rc = 0;
 231         int lower_flags;
 232         struct ecryptfs_crypt_stat *crypt_stat;
 233         struct dentry *lower_dentry;
 234         struct file *lower_file;
 235         struct inode *inode, *lower_inode;
 236         struct vfsmount *lower_mnt;
 237
 238         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 239         ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
 240                         lower_dentry->d_name.name);
 241         inode = ecryptfs_dentry->d_inode;
 242         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 243         lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
 244 #if BITS_PER_LONG != 32
 245         lower_flags |= O_LARGEFILE;
 246 #endif
 247         lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
 248         /* Corresponding fput() at end of this function */
 249         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 250                                            lower_flags))) {
 251                 ecryptfs_printk(KERN_ERR,
 252                                 "Error opening dentry; rc = [%i]\n", rc);
 253                 goto out;
 254         }
 255         lower_inode = lower_dentry->d_inode;
 256         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 257                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 258                 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
 259                 goto out_fput;
 260         }
 261         ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
 262         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 263         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 264         if (rc) {
 265                 ecryptfs_printk(KERN_DEBUG, "Error creating new file "
 266                                 "context\n");
 267                 goto out_fput;
 268         }
 269         rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
 270         if (rc) {
 271                 ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
 272                 goto out_fput;
 273         }
 274         rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
 275 out_fput:
 276         if ((rc = ecryptfs_close_lower_file(lower_file)))
 277                 printk(KERN_ERR "Error closing lower_file\n");
 278 out:
 279         return rc;
 280 }
 281
 282 /**
 283  * ecryptfs_create
 284  * @dir: The inode of the directory in which to create the file.
 285  * @dentry: The eCryptfs dentry
 286  * @mode: The mode of the new file.
 287  * @nd: nameidata
 288  *
 289  * Creates a new file.
 290  *
 291  * Returns zero on success; non-zero on error condition
 292  */
 293 static int
 294 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 295                 int mode, struct nameidata *nd)
 296 {
 297         int rc;
 298
 299         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 300         if (unlikely(rc)) {
 301                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 302                                 "lower filesystem\n");
 303                 goto out;
 304         }
 305         /* At this point, a file exists on "disk"; we need to make sure
 306          * that this on disk file is prepared to be an ecryptfs file */
 307         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 308 out:
 309         return rc;
 310 }
 311
 312 /**
 313  * ecryptfs_lookup
 314  * @dir: inode
 315  * @dentry: The dentry
 316  * @nd: nameidata, may be NULL
 317  *
 318  * Find a file on disk. If the file does not exist, then we'll add it to the
 319  * dentry cache and continue on to read it from the disk.
 320  */
 321 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 322                                       struct nameidata *nd)
 323 {
 324         int rc = 0;
 325         struct dentry *lower_dir_dentry;
 326         struct dentry *lower_dentry;
 327         struct vfsmount *lower_mnt;
 328         struct dentry *tlower_dentry = NULL;
 329         char *encoded_name;
 330         unsigned int encoded_namelen;
 331         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 332         char *page_virt = NULL;
 333         struct inode *lower_inode;
 334         u64 file_size;
 335
 336         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 337         dentry->d_op = &ecryptfs_dops;
 338         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 339             || (dentry->d_name.len == 2 && !strcmp(dentry->d_name.name, "..")))
 340                 goto out_drop;
 341         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 342                                                    dentry->d_name.name,
 343                                                    dentry->d_name.len,
 344                                                    &encoded_name);
 345         if (encoded_namelen < 0) {
 346                 rc = encoded_namelen;
 347                 goto out_drop;
 348         }
 349         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 350                         "= [%d]\n", encoded_name, encoded_namelen);
 351         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 352                                       encoded_namelen - 1);
 353         kfree(encoded_name);
 354         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 355         if (IS_ERR(lower_dentry)) {
 356                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 357                 rc = PTR_ERR(lower_dentry);
 358                 goto out_drop;
 359         }
 360         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 361                 "d_name.name = [%s]\n", lower_dentry,
 362                 lower_dentry->d_name.name);
 363         lower_inode = lower_dentry->d_inode;
 364         ecryptfs_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 365         BUG_ON(!atomic_read(&lower_dentry->d_count));
 366         ecryptfs_set_dentry_private(dentry,
 367                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 368                                                      SLAB_KERNEL));
 369         if (!ecryptfs_dentry_to_private(dentry)) {
 370                 rc = -ENOMEM;
 371                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 372                                 "to allocate ecryptfs_dentry_info struct\n");
 373                 goto out_dput;
 374         }
 375         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 376         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 377         if (!lower_dentry->d_inode) {
 378                 /* We want to add because we couldn't find in lower */
 379                 d_add(dentry, NULL);
 380                 goto out;
 381         }
 382         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 383         if (rc) {
 384                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 385                 goto out_dput;
 386         }
 387         if (S_ISDIR(lower_inode->i_mode)) {
 388                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 389                 goto out;
 390         }
 391         if (S_ISLNK(lower_inode->i_mode)) {
 392                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 393                 goto out;
 394         }
 395         if (!nd) {
 396                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 397                                 "as we *think* we are about to unlink\n");
 398                 goto out;
 399         }
 400         tlower_dentry = dget(lower_dentry);
 401         if (!tlower_dentry || IS_ERR(tlower_dentry)) {
 402                 rc = -ENOMEM;
 403                 ecryptfs_printk(KERN_ERR, "Cannot dget lower_dentry\n");
 404                 goto out_dput;
 405         }
 406         /* Released in this function */
 407         page_virt =
 408             (char *)kmem_cache_alloc(ecryptfs_header_cache_2,
 409                                      SLAB_USER);
 410         if (!page_virt) {
 411                 rc = -ENOMEM;
 412                 ecryptfs_printk(KERN_ERR,
 413                                 "Cannot ecryptfs_kmalloc a page\n");
 414                 goto out_dput;
 415         }
 416         memset(page_virt, 0, PAGE_CACHE_SIZE);
 417         rc = ecryptfs_read_header_region(page_virt, tlower_dentry, nd->mnt);
 418         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 419         if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
 420                 ecryptfs_set_default_sizes(crypt_stat);
 421         if (rc) {
 422                 rc = 0;
 423                 ecryptfs_printk(KERN_WARNING, "Error reading header region;"
 424                                 " assuming unencrypted\n");
 425         } else {
 426                 if (!contains_ecryptfs_marker(page_virt
 427                                               + ECRYPTFS_FILE_SIZE_BYTES)) {
 428                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 429                         goto out;
 430                 }
 431                 memcpy(&file_size, page_virt, sizeof(file_size));
 432                 file_size = be64_to_cpu(file_size);
 433                 i_size_write(dentry->d_inode, (loff_t)file_size);
 434         }
 435         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 436         goto out;
 437
 438 out_dput:
 439         dput(lower_dentry);
 440         if (tlower_dentry)
 441                 dput(tlower_dentry);
 442 out_drop:
 443         d_drop(dentry);
 444 out:
 445         return ERR_PTR(rc);
 446 }
 447
 448 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 449                          struct dentry *new_dentry)
 450 {
 451         struct dentry *lower_old_dentry;
 452         struct dentry *lower_new_dentry;
 453         struct dentry *lower_dir_dentry;
 454         u64 file_size_save;
 455         int rc;
 456
 457         file_size_save = i_size_read(old_dentry->d_inode);
 458         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 459         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 460         dget(lower_old_dentry);
 461         dget(lower_new_dentry);
 462         lower_dir_dentry = lock_parent(lower_new_dentry);
 463         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 464                       lower_new_dentry);
 465         if (rc || !lower_new_dentry->d_inode)
 466                 goto out_lock;
 467         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 468         if (rc)
 469                 goto out_lock;
 470         ecryptfs_copy_attr_timesizes(dir, lower_new_dentry->d_inode);
 471         old_dentry->d_inode->i_nlink =
 472                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 473         i_size_write(new_dentry->d_inode, file_size_save);
 474 out_lock:
 475         unlock_dir(lower_dir_dentry);
 476         dput(lower_new_dentry);
 477         dput(lower_old_dentry);
 478         if (!new_dentry->d_inode)
 479                 d_drop(new_dentry);
 480         return rc;
 481 }
 482
 483 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 484 {
 485         int rc = 0;
 486         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 487         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 488
 489         lock_parent(lower_dentry);
 490         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 491         if (rc) {
 492                 ecryptfs_printk(KERN_ERR, "Error in vfs_unlink\n");
 493                 goto out_unlock;
 494         }
 495         ecryptfs_copy_attr_times(dir, lower_dir_inode);
 496         dentry->d_inode->i_nlink =
 497                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 498         dentry->d_inode->i_ctime = dir->i_ctime;
 499 out_unlock:
 500         unlock_parent(lower_dentry);
 501         return rc;
 502 }
 503
 504 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 505                             const char *symname)
 506 {
 507         int rc;
 508         struct dentry *lower_dentry;
 509         struct dentry *lower_dir_dentry;
 510         umode_t mode;
 511         char *encoded_symname;
 512         unsigned int encoded_symlen;
 513         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 514
 515         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 516         dget(lower_dentry);
 517         lower_dir_dentry = lock_parent(lower_dentry);
 518         mode = S_IALLUGO;
 519         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 520                                                   strlen(symname),
 521                                                   &encoded_symname);
 522         if (encoded_symlen < 0) {
 523                 rc = encoded_symlen;
 524                 goto out_lock;
 525         }
 526         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 527                          encoded_symname, mode);
 528         kfree(encoded_symname);
 529         if (rc || !lower_dentry->d_inode)
 530                 goto out_lock;
 531         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 532         if (rc)
 533                 goto out_lock;
 534         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
 535 out_lock:
 536         unlock_dir(lower_dir_dentry);
 537         dput(lower_dentry);
 538         if (!dentry->d_inode)
 539                 d_drop(dentry);
 540         return rc;
 541 }
 542
 543 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 544 {
 545         int rc;
 546         struct dentry *lower_dentry;
 547         struct dentry *lower_dir_dentry;
 548
 549         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 550         lower_dir_dentry = lock_parent(lower_dentry);
 551         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 552         if (rc || !lower_dentry->d_inode)
 553                 goto out;
 554         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 555         if (rc)
 556                 goto out;
 557         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
 558         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 559 out:
 560         unlock_dir(lower_dir_dentry);
 561         if (!dentry->d_inode)
 562                 d_drop(dentry);
 563         return rc;
 564 }
 565
 566 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 567 {
 568         int rc = 0;
 569         struct dentry *tdentry = NULL;
 570         struct dentry *lower_dentry;
 571         struct dentry *tlower_dentry = NULL;
 572         struct dentry *lower_dir_dentry;
 573
 574         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 575         if (!(tdentry = dget(dentry))) {
 576                 rc = -EINVAL;
 577                 ecryptfs_printk(KERN_ERR, "Error dget'ing dentry [%p]\n",
 578                                 dentry);
 579                 goto out;
 580         }
 581         lower_dir_dentry = lock_parent(lower_dentry);
 582         if (!(tlower_dentry = dget(lower_dentry))) {
 583                 rc = -EINVAL;
 584                 ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry "
 585                                 "[%p]\n", lower_dentry);
 586                 goto out;
 587         }
 588         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 589         if (!rc) {
 590                 d_delete(tlower_dentry);
 591                 tlower_dentry = NULL;
 592         }
 593         ecryptfs_copy_attr_times(dir, lower_dir_dentry->d_inode);
 594         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 595         unlock_dir(lower_dir_dentry);
 596         if (!rc)
 597                 d_drop(dentry);
 598 out:
 599         if (tdentry)
 600                 dput(tdentry);
 601         if (tlower_dentry)
 602                 dput(tlower_dentry);
 603         return rc;
 604 }
 605
 606 static int
 607 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 608 {
 609         int rc;
 610         struct dentry *lower_dentry;
 611         struct dentry *lower_dir_dentry;
 612
 613         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 614         lower_dir_dentry = lock_parent(lower_dentry);
 615         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 616         if (rc || !lower_dentry->d_inode)
 617                 goto out;
 618         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 619         if (rc)
 620                 goto out;
 621         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
 622 out:
 623         unlock_dir(lower_dir_dentry);
 624         if (!dentry->d_inode)
 625                 d_drop(dentry);
 626         return rc;
 627 }
 628
 629 static int
 630 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 631                 struct inode *new_dir, struct dentry *new_dentry)
 632 {
 633         int rc;
 634         struct dentry *lower_old_dentry;
 635         struct dentry *lower_new_dentry;
 636         struct dentry *lower_old_dir_dentry;
 637         struct dentry *lower_new_dir_dentry;
 638
 639         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 640         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 641         dget(lower_old_dentry);
 642         dget(lower_new_dentry);
 643         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 644         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 645         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 646         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 647                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 648         if (rc)
 649                 goto out_lock;
 650         ecryptfs_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
 651         if (new_dir != old_dir)
 652                 ecryptfs_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
 653 out_lock:
 654         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 655         dput(lower_new_dentry);
 656         dput(lower_old_dentry);
 657         return rc;
 658 }
 659
 660 static int
 661 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 662 {
 663         int rc;
 664         struct dentry *lower_dentry;
 665         char *decoded_name;
 666         char *lower_buf;
 667         mm_segment_t old_fs;
 668         struct ecryptfs_crypt_stat *crypt_stat;
 669
 670         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 671         if (!lower_dentry->d_inode->i_op ||
 672             !lower_dentry->d_inode->i_op->readlink) {
 673                 rc = -EINVAL;
 674                 goto out;
 675         }
 676         /* Released in this function */
 677         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 678         if (lower_buf == NULL) {
 679                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 680                 rc = -ENOMEM;
 681                 goto out;
 682         }
 683         old_fs = get_fs();
 684         set_fs(get_ds());
 685         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 686                         "lower_dentry->d_name.name = [%s]\n",
 687                         lower_dentry->d_name.name);
 688         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 689                                                    (char __user *)lower_buf,
 690                                                    bufsiz);
 691         set_fs(old_fs);
 692         if (rc >= 0) {
 693                 crypt_stat = NULL;
 694                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 695                                               &decoded_name);
 696                 if (rc == -ENOMEM)
 697                         goto out_free_lower_buf;
 698                 if (rc > 0) {
 699                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 700                                         "to userspace: [%*s]\n", rc,
 701                                         decoded_name);
 702                         if (copy_to_user(buf, decoded_name, rc))
 703                                 rc = -EFAULT;
 704                 }
 705                 kfree(decoded_name);
 706                 ecryptfs_copy_attr_atime(dentry->d_inode,
 707                                          lower_dentry->d_inode);
 708         }
 709 out_free_lower_buf:
 710         kfree(lower_buf);
 711 out:
 712         return rc;
 713 }
 714
 715 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 716 {
 717         char *buf;
 718         int len = PAGE_SIZE, rc;
 719         mm_segment_t old_fs;
 720
 721         /* Released in ecryptfs_put_link(); only release here on error */
 722         buf = kmalloc(len, GFP_KERNEL);
 723         if (!buf) {
 724                 rc = -ENOMEM;
 725                 goto out;
 726         }
 727         old_fs = get_fs();
 728         set_fs(get_ds());
 729         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 730                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 731         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 732         buf[rc] = '\0';
 733         set_fs(old_fs);
 734         if (rc < 0)
 735                 goto out_free;
 736         rc = 0;
 737         nd_set_link(nd, buf);
 738         goto out;
 739 out_free:
 740         kfree(buf);
 741 out:
 742         return ERR_PTR(rc);
 743 }
 744
 745 static void
 746 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 747 {
 748         /* Free the char* */
 749         kfree(nd_get_link(nd));
 750 }
 751
 752 /**
 753  * upper_size_to_lower_size
 754  * @crypt_stat: Crypt_stat associated with file
 755  * @upper_size: Size of the upper file
 756  *
 757  * Calculate the requried size of the lower file based on the
 758  * specified size of the upper file. This calculation is based on the
 759  * number of headers in the underlying file and the extent size.
 760  *
 761  * Returns Calculated size of the lower file.
 762  */
 763 static loff_t
 764 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 765                          loff_t upper_size)
 766 {
 767         loff_t lower_size;
 768
 769         lower_size = ( crypt_stat->header_extent_size
 770                        * crypt_stat->num_header_extents_at_front );
 771         if (upper_size != 0) {
 772                 loff_t num_extents;
 773
 774                 num_extents = upper_size >> crypt_stat->extent_shift;
 775                 if (upper_size & ~crypt_stat->extent_mask)
 776                         num_extents++;
 777                 lower_size += (num_extents * crypt_stat->extent_size);
 778         }
 779         return lower_size;
 780 }
 781
 782 /**
 783  * ecryptfs_truncate
 784  * @dentry: The ecryptfs layer dentry
 785  * @new_length: The length to expand the file to
 786  *
 787  * Function to handle truncations modifying the size of the file. Note
 788  * that the file sizes are interpolated. When expanding, we are simply
 789  * writing strings of 0's out. When truncating, we need to modify the
 790  * underlying file size according to the page index interpolations.
 791  *
 792  * Returns zero on success; non-zero otherwise
 793  */
 794 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 795 {
 796         int rc = 0;
 797         struct inode *inode = dentry->d_inode;
 798         struct dentry *lower_dentry;
 799         struct vfsmount *lower_mnt;
 800         struct file fake_ecryptfs_file, *lower_file = NULL;
 801         struct ecryptfs_crypt_stat *crypt_stat;
 802         loff_t i_size = i_size_read(inode);
 803         loff_t lower_size_before_truncate;
 804         loff_t lower_size_after_truncate;
 805
 806         if (unlikely((new_length == i_size)))
 807                 goto out;
 808         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 809         /* Set up a fake ecryptfs file, this is used to interface with
 810          * the file in the underlying filesystem so that the
 811          * truncation has an effect there as well. */
 812         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 813         fake_ecryptfs_file.f_dentry = dentry;
 814         /* Released at out_free: label */
 815         ecryptfs_set_file_private(&fake_ecryptfs_file,
 816                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 817                                                    SLAB_KERNEL));
 818         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 819                 rc = -ENOMEM;
 820                 goto out;
 821         }
 822         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 823         /* This dget & mntget is released through fput at out_fput: */
 824         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 825         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 826                                            O_RDWR))) {
 827                 ecryptfs_printk(KERN_ERR,
 828                                 "Error opening dentry; rc = [%i]\n", rc);
 829                 goto out_free;
 830         }
 831         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 832         /* Switch on growing or shrinking file */
 833         if (new_length > i_size) {
 834                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 835                 if (rc) {
 836                         ecryptfs_printk(KERN_ERR,
 837                                         "Problem with fill_zeros\n");
 838                         goto out_fput;
 839                 }
 840                 i_size_write(inode, new_length);
 841                 rc = ecryptfs_write_inode_size_to_header(lower_file,
 842                                                          lower_dentry->d_inode,
 843                                                          inode);
 844                 if (rc) {
 845                         ecryptfs_printk(KERN_ERR,
 846                                         "Problem with ecryptfs_write"
 847                                         "_inode_size\n");
 848                         goto out_fput;
 849                 }
 850         } else { /* new_length < i_size_read(inode) */
 851                 vmtruncate(inode, new_length);
 852                 ecryptfs_write_inode_size_to_header(lower_file,
 853                                                     lower_dentry->d_inode,
 854                                                     inode);
 855                 /* We are reducing the size of the ecryptfs file, and need to
 856                  * know if we need to reduce the size of the lower file. */
 857                 lower_size_before_truncate =
 858                     upper_size_to_lower_size(crypt_stat, i_size);
 859                 lower_size_after_truncate =
 860                     upper_size_to_lower_size(crypt_stat, new_length);
 861                 if (lower_size_after_truncate < lower_size_before_truncate)
 862                         vmtruncate(lower_dentry->d_inode,
 863                                    lower_size_after_truncate);
 864         }
 865         /* Update the access times */
 866         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 867                 = CURRENT_TIME;
 868         mark_inode_dirty_sync(inode);
 869 out_fput:
 870         if ((rc = ecryptfs_close_lower_file(lower_file)))
 871                 printk(KERN_ERR "Error closing lower_file\n");
 872 out_free:
 873         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 874                 kmem_cache_free(ecryptfs_file_info_cache,
 875                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 876 out:
 877         return rc;
 878 }
 879
 880 static int
 881 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 882 {
 883         int rc;
 884
 885         if (nd) {
 886                 struct vfsmount *vfsmnt_save = nd->mnt;
 887                 struct dentry *dentry_save = nd->dentry;
 888
 889                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 890                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 891                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 892                 nd->mnt = vfsmnt_save;
 893                 nd->dentry = dentry_save;
 894         } else
 895                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 896         return rc;
 897 }
 898
 899 /**
 900  * ecryptfs_setattr
 901  * @dentry: dentry handle to the inode to modify
 902  * @ia: Structure with flags of what to change and values
 903  *
 904  * Updates the metadata of an inode. If the update is to the size
 905  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 906  * of both the ecryptfs inode and the lower inode.
 907  *
 908  * All other metadata changes will be passed right to the lower filesystem,
 909  * and we will just update our inode to look like the lower.
 910  */
 911 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 912 {
 913         int rc = 0;
 914         struct dentry *lower_dentry;
 915         struct inode *inode;
 916         struct inode *lower_inode;
 917         struct ecryptfs_crypt_stat *crypt_stat;
 918
 919         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 920         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 921         inode = dentry->d_inode;
 922         lower_inode = ecryptfs_inode_to_lower(inode);
 923         if (ia->ia_valid & ATTR_SIZE) {
 924                 ecryptfs_printk(KERN_DEBUG,
 925                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 926                                 ia->ia_valid, ATTR_SIZE);
 927                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 928                 /* ecryptfs_truncate handles resizing of the lower file */
 929                 ia->ia_valid &= ~ATTR_SIZE;
 930                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 931                                 ia->ia_valid);
 932                 if (rc < 0)
 933                         goto out;
 934         }
 935         rc = notify_change(lower_dentry, ia);
 936 out:
 937         ecryptfs_copy_attr_all(inode, lower_inode);
 938         return rc;
 939 }
 940
 941 static int
 942 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 943                   size_t size, int flags)
 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->setxattr) {
 950                 rc = -ENOSYS;
 951                 goto out;
 952         }
 953         mutex_lock(&lower_dentry->d_inode->i_mutex);
 954         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 955                                                    size, flags);
 956         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 957 out:
 958         return rc;
 959 }
 960
 961 static ssize_t
 962 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 963                   size_t size)
 964 {
 965         int rc = 0;
 966         struct dentry *lower_dentry;
 967
 968         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 969         if (!lower_dentry->d_inode->i_op->getxattr) {
 970                 rc = -ENOSYS;
 971                 goto out;
 972         }
 973         mutex_lock(&lower_dentry->d_inode->i_mutex);
 974         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 975                                                    size);
 976         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 977 out:
 978         return rc;
 979 }
 980
 981 static ssize_t
 982 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 983 {
 984         int rc = 0;
 985         struct dentry *lower_dentry;
 986
 987         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 988         if (!lower_dentry->d_inode->i_op->listxattr) {
 989                 rc = -ENOSYS;
 990                 goto out;
 991         }
 992         mutex_lock(&lower_dentry->d_inode->i_mutex);
 993         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
 994         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 995 out:
 996         return rc;
 997 }
 998
 999 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1000 {
1001         int rc = 0;
1002         struct dentry *lower_dentry;
1003
1004         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1005         if (!lower_dentry->d_inode->i_op->removexattr) {
1006                 rc = -ENOSYS;
1007                 goto out;
1008         }
1009         mutex_lock(&lower_dentry->d_inode->i_mutex);
1010         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1011         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1012 out:
1013         return rc;
1014 }
1015
1016 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1017 {
1018         if ((ecryptfs_inode_to_lower(inode)
1019              == (struct inode *)candidate_lower_inode))
1020                 return 1;
1021         else
1022                 return 0;
1023 }
1024
1025 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1026 {
1027         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1028         return 0;
1029 }
1030
1031 struct inode_operations ecryptfs_symlink_iops = {
1032         .readlink = ecryptfs_readlink,
1033         .follow_link = ecryptfs_follow_link,
1034         .put_link = ecryptfs_put_link,
1035         .permission = ecryptfs_permission,
1036         .setattr = ecryptfs_setattr,
1037         .setxattr = ecryptfs_setxattr,
1038         .getxattr = ecryptfs_getxattr,
1039         .listxattr = ecryptfs_listxattr,
1040         .removexattr = ecryptfs_removexattr
1041 };
1042
1043 struct inode_operations ecryptfs_dir_iops = {
1044         .create = ecryptfs_create,
1045         .lookup = ecryptfs_lookup,
1046         .link = ecryptfs_link,
1047         .unlink = ecryptfs_unlink,
1048         .symlink = ecryptfs_symlink,
1049         .mkdir = ecryptfs_mkdir,
1050         .rmdir = ecryptfs_rmdir,
1051         .mknod = ecryptfs_mknod,
1052         .rename = ecryptfs_rename,
1053         .permission = ecryptfs_permission,
1054         .setattr = ecryptfs_setattr,
1055         .setxattr = ecryptfs_setxattr,
1056         .getxattr = ecryptfs_getxattr,
1057         .listxattr = ecryptfs_listxattr,
1058         .removexattr = ecryptfs_removexattr
1059 };
1060
1061 struct inode_operations ecryptfs_main_iops = {
1062         .permission = ecryptfs_permission,
1063         .setattr = ecryptfs_setattr,
1064         .setxattr = ecryptfs_setxattr,
1065         .getxattr = ecryptfs_getxattr,
1066         .listxattr = ecryptfs_listxattr,
1067         .removexattr = ecryptfs_removexattr
1068 };