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         char *encoded_name;
 329         unsigned int encoded_namelen;
 330         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 331         char *page_virt = NULL;
 332         struct inode *lower_inode;
 333         u64 file_size;
 334
 335         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 336         dentry->d_op = &ecryptfs_dops;
 337         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 338             || (dentry->d_name.len == 2
 339                 && !strcmp(dentry->d_name.name, ".."))) {
 340                 d_drop(dentry);
 341                 goto out;
 342         }
 343         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 344                                                    dentry->d_name.name,
 345                                                    dentry->d_name.len,
 346                                                    &encoded_name);
 347         if (encoded_namelen < 0) {
 348                 rc = encoded_namelen;
 349                 d_drop(dentry);
 350                 goto out;
 351         }
 352         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 353                         "= [%d]\n", encoded_name, encoded_namelen);
 354         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 355                                       encoded_namelen - 1);
 356         kfree(encoded_name);
 357         if (IS_ERR(lower_dentry)) {
 358                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 359                 rc = PTR_ERR(lower_dentry);
 360                 d_drop(dentry);
 361                 goto out;
 362         }
 363         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 364         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 365                 "d_name.name = [%s]\n", lower_dentry,
 366                 lower_dentry->d_name.name);
 367         lower_inode = lower_dentry->d_inode;
 368         ecryptfs_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 369         BUG_ON(!atomic_read(&lower_dentry->d_count));
 370         ecryptfs_set_dentry_private(dentry,
 371                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 372                                                      SLAB_KERNEL));
 373         if (!ecryptfs_dentry_to_private(dentry)) {
 374                 rc = -ENOMEM;
 375                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 376                                 "to allocate ecryptfs_dentry_info struct\n");
 377                 goto out_dput;
 378         }
 379         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 380         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 381         if (!lower_dentry->d_inode) {
 382                 /* We want to add because we couldn't find in lower */
 383                 d_add(dentry, NULL);
 384                 goto out;
 385         }
 386         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 387         if (rc) {
 388                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 389                 goto out_dput;
 390         }
 391         if (S_ISDIR(lower_inode->i_mode)) {
 392                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 393                 goto out;
 394         }
 395         if (S_ISLNK(lower_inode->i_mode)) {
 396                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 397                 goto out;
 398         }
 399         if (!nd) {
 400                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 401                                 "as we *think* we are about to unlink\n");
 402                 goto out;
 403         }
 404         /* Released in this function */
 405         page_virt =
 406             (char *)kmem_cache_alloc(ecryptfs_header_cache_2,
 407                                      SLAB_USER);
 408         if (!page_virt) {
 409                 rc = -ENOMEM;
 410                 ecryptfs_printk(KERN_ERR,
 411                                 "Cannot ecryptfs_kmalloc a page\n");
 412                 goto out_dput;
 413         }
 414         memset(page_virt, 0, PAGE_CACHE_SIZE);
 415         rc = ecryptfs_read_header_region(page_virt, lower_dentry, nd->mnt);
 416         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 417         if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
 418                 ecryptfs_set_default_sizes(crypt_stat);
 419         if (rc) {
 420                 rc = 0;
 421                 ecryptfs_printk(KERN_WARNING, "Error reading header region;"
 422                                 " assuming unencrypted\n");
 423         } else {
 424                 if (!contains_ecryptfs_marker(page_virt
 425                                               + ECRYPTFS_FILE_SIZE_BYTES)) {
 426                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 427                         goto out;
 428                 }
 429                 memcpy(&file_size, page_virt, sizeof(file_size));
 430                 file_size = be64_to_cpu(file_size);
 431                 i_size_write(dentry->d_inode, (loff_t)file_size);
 432         }
 433         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 434         goto out;
 435
 436 out_dput:
 437         dput(lower_dentry);
 438         d_drop(dentry);
 439 out:
 440         return ERR_PTR(rc);
 441 }
 442
 443 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 444                          struct dentry *new_dentry)
 445 {
 446         struct dentry *lower_old_dentry;
 447         struct dentry *lower_new_dentry;
 448         struct dentry *lower_dir_dentry;
 449         u64 file_size_save;
 450         int rc;
 451
 452         file_size_save = i_size_read(old_dentry->d_inode);
 453         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 454         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 455         dget(lower_old_dentry);
 456         dget(lower_new_dentry);
 457         lower_dir_dentry = lock_parent(lower_new_dentry);
 458         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 459                       lower_new_dentry);
 460         if (rc || !lower_new_dentry->d_inode)
 461                 goto out_lock;
 462         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 463         if (rc)
 464                 goto out_lock;
 465         ecryptfs_copy_attr_timesizes(dir, lower_new_dentry->d_inode);
 466         old_dentry->d_inode->i_nlink =
 467                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 468         i_size_write(new_dentry->d_inode, file_size_save);
 469 out_lock:
 470         unlock_dir(lower_dir_dentry);
 471         dput(lower_new_dentry);
 472         dput(lower_old_dentry);
 473         d_drop(new_dentry);
 474         d_drop(old_dentry);
 475         return rc;
 476 }
 477
 478 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 479 {
 480         int rc = 0;
 481         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 482         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 483
 484         lock_parent(lower_dentry);
 485         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 486         if (rc) {
 487                 ecryptfs_printk(KERN_ERR, "Error in vfs_unlink\n");
 488                 goto out_unlock;
 489         }
 490         ecryptfs_copy_attr_times(dir, lower_dir_inode);
 491         dentry->d_inode->i_nlink =
 492                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 493         dentry->d_inode->i_ctime = dir->i_ctime;
 494 out_unlock:
 495         unlock_parent(lower_dentry);
 496         return rc;
 497 }
 498
 499 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 500                             const char *symname)
 501 {
 502         int rc;
 503         struct dentry *lower_dentry;
 504         struct dentry *lower_dir_dentry;
 505         umode_t mode;
 506         char *encoded_symname;
 507         unsigned int encoded_symlen;
 508         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 509
 510         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 511         dget(lower_dentry);
 512         lower_dir_dentry = lock_parent(lower_dentry);
 513         mode = S_IALLUGO;
 514         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 515                                                   strlen(symname),
 516                                                   &encoded_symname);
 517         if (encoded_symlen < 0) {
 518                 rc = encoded_symlen;
 519                 goto out_lock;
 520         }
 521         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 522                          encoded_symname, mode);
 523         kfree(encoded_symname);
 524         if (rc || !lower_dentry->d_inode)
 525                 goto out_lock;
 526         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 527         if (rc)
 528                 goto out_lock;
 529         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
 530 out_lock:
 531         unlock_dir(lower_dir_dentry);
 532         dput(lower_dentry);
 533         if (!dentry->d_inode)
 534                 d_drop(dentry);
 535         return rc;
 536 }
 537
 538 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 539 {
 540         int rc;
 541         struct dentry *lower_dentry;
 542         struct dentry *lower_dir_dentry;
 543
 544         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 545         lower_dir_dentry = lock_parent(lower_dentry);
 546         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 547         if (rc || !lower_dentry->d_inode)
 548                 goto out;
 549         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 550         if (rc)
 551                 goto out;
 552         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
 553         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 554 out:
 555         unlock_dir(lower_dir_dentry);
 556         if (!dentry->d_inode)
 557                 d_drop(dentry);
 558         return rc;
 559 }
 560
 561 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 562 {
 563         struct dentry *lower_dentry;
 564         struct dentry *lower_dir_dentry;
 565         int rc;
 566
 567         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 568         dget(dentry);
 569         lower_dir_dentry = lock_parent(lower_dentry);
 570         dget(lower_dentry);
 571         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 572         dput(lower_dentry);
 573         if (!rc)
 574                 d_delete(lower_dentry);
 575         ecryptfs_copy_attr_times(dir, lower_dir_dentry->d_inode);
 576         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 577         unlock_dir(lower_dir_dentry);
 578         if (!rc)
 579                 d_drop(dentry);
 580         dput(dentry);
 581         return rc;
 582 }
 583
 584 static int
 585 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 586 {
 587         int rc;
 588         struct dentry *lower_dentry;
 589         struct dentry *lower_dir_dentry;
 590
 591         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 592         lower_dir_dentry = lock_parent(lower_dentry);
 593         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 594         if (rc || !lower_dentry->d_inode)
 595                 goto out;
 596         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 597         if (rc)
 598                 goto out;
 599         ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
 600 out:
 601         unlock_dir(lower_dir_dentry);
 602         if (!dentry->d_inode)
 603                 d_drop(dentry);
 604         return rc;
 605 }
 606
 607 static int
 608 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 609                 struct inode *new_dir, struct dentry *new_dentry)
 610 {
 611         int rc;
 612         struct dentry *lower_old_dentry;
 613         struct dentry *lower_new_dentry;
 614         struct dentry *lower_old_dir_dentry;
 615         struct dentry *lower_new_dir_dentry;
 616
 617         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 618         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 619         dget(lower_old_dentry);
 620         dget(lower_new_dentry);
 621         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 622         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 623         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 624         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 625                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 626         if (rc)
 627                 goto out_lock;
 628         ecryptfs_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
 629         if (new_dir != old_dir)
 630                 ecryptfs_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
 631 out_lock:
 632         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 633         dput(lower_new_dentry);
 634         dput(lower_old_dentry);
 635         return rc;
 636 }
 637
 638 static int
 639 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 640 {
 641         int rc;
 642         struct dentry *lower_dentry;
 643         char *decoded_name;
 644         char *lower_buf;
 645         mm_segment_t old_fs;
 646         struct ecryptfs_crypt_stat *crypt_stat;
 647
 648         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 649         if (!lower_dentry->d_inode->i_op ||
 650             !lower_dentry->d_inode->i_op->readlink) {
 651                 rc = -EINVAL;
 652                 goto out;
 653         }
 654         /* Released in this function */
 655         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 656         if (lower_buf == NULL) {
 657                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 658                 rc = -ENOMEM;
 659                 goto out;
 660         }
 661         old_fs = get_fs();
 662         set_fs(get_ds());
 663         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 664                         "lower_dentry->d_name.name = [%s]\n",
 665                         lower_dentry->d_name.name);
 666         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 667                                                    (char __user *)lower_buf,
 668                                                    bufsiz);
 669         set_fs(old_fs);
 670         if (rc >= 0) {
 671                 crypt_stat = NULL;
 672                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 673                                               &decoded_name);
 674                 if (rc == -ENOMEM)
 675                         goto out_free_lower_buf;
 676                 if (rc > 0) {
 677                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 678                                         "to userspace: [%*s]\n", rc,
 679                                         decoded_name);
 680                         if (copy_to_user(buf, decoded_name, rc))
 681                                 rc = -EFAULT;
 682                 }
 683                 kfree(decoded_name);
 684                 ecryptfs_copy_attr_atime(dentry->d_inode,
 685                                          lower_dentry->d_inode);
 686         }
 687 out_free_lower_buf:
 688         kfree(lower_buf);
 689 out:
 690         return rc;
 691 }
 692
 693 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 694 {
 695         char *buf;
 696         int len = PAGE_SIZE, rc;
 697         mm_segment_t old_fs;
 698
 699         /* Released in ecryptfs_put_link(); only release here on error */
 700         buf = kmalloc(len, GFP_KERNEL);
 701         if (!buf) {
 702                 rc = -ENOMEM;
 703                 goto out;
 704         }
 705         old_fs = get_fs();
 706         set_fs(get_ds());
 707         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 708                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 709         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 710         buf[rc] = '\0';
 711         set_fs(old_fs);
 712         if (rc < 0)
 713                 goto out_free;
 714         rc = 0;
 715         nd_set_link(nd, buf);
 716         goto out;
 717 out_free:
 718         kfree(buf);
 719 out:
 720         return ERR_PTR(rc);
 721 }
 722
 723 static void
 724 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 725 {
 726         /* Free the char* */
 727         kfree(nd_get_link(nd));
 728 }
 729
 730 /**
 731  * upper_size_to_lower_size
 732  * @crypt_stat: Crypt_stat associated with file
 733  * @upper_size: Size of the upper file
 734  *
 735  * Calculate the requried size of the lower file based on the
 736  * specified size of the upper file. This calculation is based on the
 737  * number of headers in the underlying file and the extent size.
 738  *
 739  * Returns Calculated size of the lower file.
 740  */
 741 static loff_t
 742 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 743                          loff_t upper_size)
 744 {
 745         loff_t lower_size;
 746
 747         lower_size = ( crypt_stat->header_extent_size
 748                        * crypt_stat->num_header_extents_at_front );
 749         if (upper_size != 0) {
 750                 loff_t num_extents;
 751
 752                 num_extents = upper_size >> crypt_stat->extent_shift;
 753                 if (upper_size & ~crypt_stat->extent_mask)
 754                         num_extents++;
 755                 lower_size += (num_extents * crypt_stat->extent_size);
 756         }
 757         return lower_size;
 758 }
 759
 760 /**
 761  * ecryptfs_truncate
 762  * @dentry: The ecryptfs layer dentry
 763  * @new_length: The length to expand the file to
 764  *
 765  * Function to handle truncations modifying the size of the file. Note
 766  * that the file sizes are interpolated. When expanding, we are simply
 767  * writing strings of 0's out. When truncating, we need to modify the
 768  * underlying file size according to the page index interpolations.
 769  *
 770  * Returns zero on success; non-zero otherwise
 771  */
 772 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 773 {
 774         int rc = 0;
 775         struct inode *inode = dentry->d_inode;
 776         struct dentry *lower_dentry;
 777         struct vfsmount *lower_mnt;
 778         struct file fake_ecryptfs_file, *lower_file = NULL;
 779         struct ecryptfs_crypt_stat *crypt_stat;
 780         loff_t i_size = i_size_read(inode);
 781         loff_t lower_size_before_truncate;
 782         loff_t lower_size_after_truncate;
 783
 784         if (unlikely((new_length == i_size)))
 785                 goto out;
 786         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 787         /* Set up a fake ecryptfs file, this is used to interface with
 788          * the file in the underlying filesystem so that the
 789          * truncation has an effect there as well. */
 790         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 791         fake_ecryptfs_file.f_dentry = dentry;
 792         /* Released at out_free: label */
 793         ecryptfs_set_file_private(&fake_ecryptfs_file,
 794                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 795                                                    SLAB_KERNEL));
 796         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 797                 rc = -ENOMEM;
 798                 goto out;
 799         }
 800         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 801         /* This dget & mntget is released through fput at out_fput: */
 802         lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
 803         if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
 804                                            O_RDWR))) {
 805                 ecryptfs_printk(KERN_ERR,
 806                                 "Error opening dentry; rc = [%i]\n", rc);
 807                 goto out_free;
 808         }
 809         ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
 810         /* Switch on growing or shrinking file */
 811         if (new_length > i_size) {
 812                 rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
 813                 if (rc) {
 814                         ecryptfs_printk(KERN_ERR,
 815                                         "Problem with fill_zeros\n");
 816                         goto out_fput;
 817                 }
 818                 i_size_write(inode, new_length);
 819                 rc = ecryptfs_write_inode_size_to_header(lower_file,
 820                                                          lower_dentry->d_inode,
 821                                                          inode);
 822                 if (rc) {
 823                         ecryptfs_printk(KERN_ERR,
 824                                         "Problem with ecryptfs_write"
 825                                         "_inode_size\n");
 826                         goto out_fput;
 827                 }
 828         } else { /* new_length < i_size_read(inode) */
 829                 vmtruncate(inode, new_length);
 830                 ecryptfs_write_inode_size_to_header(lower_file,
 831                                                     lower_dentry->d_inode,
 832                                                     inode);
 833                 /* We are reducing the size of the ecryptfs file, and need to
 834                  * know if we need to reduce the size of the lower file. */
 835                 lower_size_before_truncate =
 836                     upper_size_to_lower_size(crypt_stat, i_size);
 837                 lower_size_after_truncate =
 838                     upper_size_to_lower_size(crypt_stat, new_length);
 839                 if (lower_size_after_truncate < lower_size_before_truncate)
 840                         vmtruncate(lower_dentry->d_inode,
 841                                    lower_size_after_truncate);
 842         }
 843         /* Update the access times */
 844         lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
 845                 = CURRENT_TIME;
 846         mark_inode_dirty_sync(inode);
 847 out_fput:
 848         if ((rc = ecryptfs_close_lower_file(lower_file)))
 849                 printk(KERN_ERR "Error closing lower_file\n");
 850 out_free:
 851         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 852                 kmem_cache_free(ecryptfs_file_info_cache,
 853                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 854 out:
 855         return rc;
 856 }
 857
 858 static int
 859 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 860 {
 861         int rc;
 862
 863         if (nd) {
 864                 struct vfsmount *vfsmnt_save = nd->mnt;
 865                 struct dentry *dentry_save = nd->dentry;
 866
 867                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 868                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 869                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 870                 nd->mnt = vfsmnt_save;
 871                 nd->dentry = dentry_save;
 872         } else
 873                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 874         return rc;
 875 }
 876
 877 /**
 878  * ecryptfs_setattr
 879  * @dentry: dentry handle to the inode to modify
 880  * @ia: Structure with flags of what to change and values
 881  *
 882  * Updates the metadata of an inode. If the update is to the size
 883  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 884  * of both the ecryptfs inode and the lower inode.
 885  *
 886  * All other metadata changes will be passed right to the lower filesystem,
 887  * and we will just update our inode to look like the lower.
 888  */
 889 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 890 {
 891         int rc = 0;
 892         struct dentry *lower_dentry;
 893         struct inode *inode;
 894         struct inode *lower_inode;
 895         struct ecryptfs_crypt_stat *crypt_stat;
 896
 897         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 898         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 899         inode = dentry->d_inode;
 900         lower_inode = ecryptfs_inode_to_lower(inode);
 901         if (ia->ia_valid & ATTR_SIZE) {
 902                 ecryptfs_printk(KERN_DEBUG,
 903                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 904                                 ia->ia_valid, ATTR_SIZE);
 905                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 906                 /* ecryptfs_truncate handles resizing of the lower file */
 907                 ia->ia_valid &= ~ATTR_SIZE;
 908                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 909                                 ia->ia_valid);
 910                 if (rc < 0)
 911                         goto out;
 912         }
 913         rc = notify_change(lower_dentry, ia);
 914 out:
 915         ecryptfs_copy_attr_all(inode, lower_inode);
 916         return rc;
 917 }
 918
 919 static int
 920 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 921                   size_t size, int flags)
 922 {
 923         int rc = 0;
 924         struct dentry *lower_dentry;
 925
 926         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 927         if (!lower_dentry->d_inode->i_op->setxattr) {
 928                 rc = -ENOSYS;
 929                 goto out;
 930         }
 931         mutex_lock(&lower_dentry->d_inode->i_mutex);
 932         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 933                                                    size, flags);
 934         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 935 out:
 936         return rc;
 937 }
 938
 939 static ssize_t
 940 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 941                   size_t size)
 942 {
 943         int rc = 0;
 944         struct dentry *lower_dentry;
 945
 946         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 947         if (!lower_dentry->d_inode->i_op->getxattr) {
 948                 rc = -ENOSYS;
 949                 goto out;
 950         }
 951         mutex_lock(&lower_dentry->d_inode->i_mutex);
 952         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 953                                                    size);
 954         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 955 out:
 956         return rc;
 957 }
 958
 959 static ssize_t
 960 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 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->listxattr) {
 967                 rc = -ENOSYS;
 968                 goto out;
 969         }
 970         mutex_lock(&lower_dentry->d_inode->i_mutex);
 971         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
 972         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 973 out:
 974         return rc;
 975 }
 976
 977 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
 978 {
 979         int rc = 0;
 980         struct dentry *lower_dentry;
 981
 982         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 983         if (!lower_dentry->d_inode->i_op->removexattr) {
 984                 rc = -ENOSYS;
 985                 goto out;
 986         }
 987         mutex_lock(&lower_dentry->d_inode->i_mutex);
 988         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
 989         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 990 out:
 991         return rc;
 992 }
 993
 994 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
 995 {
 996         if ((ecryptfs_inode_to_lower(inode)
 997              == (struct inode *)candidate_lower_inode))
 998                 return 1;
 999         else
1000                 return 0;
1001 }
1002
1003 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1004 {
1005         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1006         return 0;
1007 }
1008
1009 struct inode_operations ecryptfs_symlink_iops = {
1010         .readlink = ecryptfs_readlink,
1011         .follow_link = ecryptfs_follow_link,
1012         .put_link = ecryptfs_put_link,
1013         .permission = ecryptfs_permission,
1014         .setattr = ecryptfs_setattr,
1015         .setxattr = ecryptfs_setxattr,
1016         .getxattr = ecryptfs_getxattr,
1017         .listxattr = ecryptfs_listxattr,
1018         .removexattr = ecryptfs_removexattr
1019 };
1020
1021 struct inode_operations ecryptfs_dir_iops = {
1022         .create = ecryptfs_create,
1023         .lookup = ecryptfs_lookup,
1024         .link = ecryptfs_link,
1025         .unlink = ecryptfs_unlink,
1026         .symlink = ecryptfs_symlink,
1027         .mkdir = ecryptfs_mkdir,
1028         .rmdir = ecryptfs_rmdir,
1029         .mknod = ecryptfs_mknod,
1030         .rename = ecryptfs_rename,
1031         .permission = ecryptfs_permission,
1032         .setattr = ecryptfs_setattr,
1033         .setxattr = ecryptfs_setxattr,
1034         .getxattr = ecryptfs_getxattr,
1035         .listxattr = ecryptfs_listxattr,
1036         .removexattr = ecryptfs_removexattr
1037 };
1038
1039 struct inode_operations ecryptfs_main_iops = {
1040         .permission = ecryptfs_permission,
1041         .setattr = ecryptfs_setattr,
1042         .setxattr = ecryptfs_setxattr,
1043         .getxattr = ecryptfs_getxattr,
1044         .listxattr = ecryptfs_listxattr,
1045         .removexattr = ecryptfs_removexattr
1046 };