fs/ecryptfs/inode.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  *
   4  * Copyright (C) 1997-2004 Erez Zadok
   5  * Copyright (C) 2001-2004 Stony Brook University
   6  * Copyright (C) 2004-2007 International Business Machines Corp.
   7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of the
  13  * License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23  * 02111-1307, USA.
  24  */
  25
  26 #include <linux/file.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/dcache.h>
  30 #include <linux/namei.h>
  31 #include <linux/mount.h>
  32 #include <linux/crypto.h>
  33 #include <linux/fs_stack.h>
  34 #include "ecryptfs_kernel.h"
  35
  36 static struct dentry *lock_parent(struct dentry *dentry)
  37 {
  38         struct dentry *dir;
  39
  40         dir = dget(dentry->d_parent);
  41         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
  42         return dir;
  43 }
  44
  45 static void unlock_parent(struct dentry *dentry)
  46 {
  47         mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
  48         dput(dentry->d_parent);
  49 }
  50
  51 static void unlock_dir(struct dentry *dir)
  52 {
  53         mutex_unlock(&dir->d_inode->i_mutex);
  54         dput(dir);
  55 }
  56
  57 /**
  58  * ecryptfs_create_underlying_file
  59  * @lower_dir_inode: inode of the parent in the lower fs of the new file
  60  * @lower_dentry: New file's dentry in the lower fs
  61  * @ecryptfs_dentry: New file's dentry in ecryptfs
  62  * @mode: The mode of the new file
  63  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  64  *
  65  * Creates the file in the lower file system.
  66  *
  67  * Returns zero on success; non-zero on error condition
  68  */
  69 static int
  70 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
  71                                 struct dentry *dentry, int mode,
  72                                 struct nameidata *nd)
  73 {
  74         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  75         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
  76         struct dentry *dentry_save;
  77         struct vfsmount *vfsmount_save;
  78         int rc;
  79
  80         dentry_save = nd->dentry;
  81         vfsmount_save = nd->mnt;
  82         nd->dentry = lower_dentry;
  83         nd->mnt = lower_mnt;
  84         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
  85         nd->dentry = dentry_save;
  86         nd->mnt = vfsmount_save;
  87         return rc;
  88 }
  89
  90 /**
  91  * ecryptfs_do_create
  92  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
  93  * @ecryptfs_dentry: New file's dentry in ecryptfs
  94  * @mode: The mode of the new file
  95  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  96  *
  97  * Creates the underlying file and the eCryptfs inode which will link to
  98  * it. It will also update the eCryptfs directory inode to mimic the
  99  * stat of the lower directory inode.
 100  *
 101  * Returns zero on success; non-zero on error condition
 102  */
 103 static int
 104 ecryptfs_do_create(struct inode *directory_inode,
 105                    struct dentry *ecryptfs_dentry, int mode,
 106                    struct nameidata *nd)
 107 {
 108         int rc;
 109         struct dentry *lower_dentry;
 110         struct dentry *lower_dir_dentry;
 111
 112         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 113         lower_dir_dentry = lock_parent(lower_dentry);
 114         if (unlikely(IS_ERR(lower_dir_dentry))) {
 115                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
 116                                 "dentry\n");
 117                 rc = PTR_ERR(lower_dir_dentry);
 118                 goto out;
 119         }
 120         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
 121                                              ecryptfs_dentry, mode, nd);
 122         if (rc) {
 123                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 124                        "rc = [%d]\n", __FUNCTION__, rc);
 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  *
 145  * This is the code which will grow the file to its correct size.
 146  */
 147 static int grow_file(struct dentry *ecryptfs_dentry)
 148 {
 149         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
 150         struct file fake_file;
 151         struct ecryptfs_file_info tmp_file_info;
 152         char zero_virt[] = { 0x00 };
 153         int rc = 0;
 154
 155         memset(&fake_file, 0, sizeof(fake_file));
 156         fake_file.f_path.dentry = ecryptfs_dentry;
 157         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
 158         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
 159         ecryptfs_set_file_lower(
 160                 &fake_file,
 161                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
 162         rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
 163         i_size_write(ecryptfs_inode, 0);
 164         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
 165         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
 166                 ECRYPTFS_NEW_FILE;
 167         return rc;
 168 }
 169
 170 /**
 171  * ecryptfs_initialize_file
 172  *
 173  * Cause the file to be changed from a basic empty file to an ecryptfs
 174  * file with a header and first data page.
 175  *
 176  * Returns zero on success
 177  */
 178 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 179 {
 180         struct ecryptfs_crypt_stat *crypt_stat =
 181                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
 182         int rc = 0;
 183
 184         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 185                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 186                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 187                 goto out;
 188         }
 189         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
 190         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 191         rc = ecryptfs_new_file_context(ecryptfs_dentry);
 192         if (rc) {
 193                 ecryptfs_printk(KERN_ERR, "Error creating new file "
 194                                 "context; rc = [%d]\n", rc);
 195                 goto out;
 196         }
 197         rc = ecryptfs_write_metadata(ecryptfs_dentry);
 198         if (rc) {
 199                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 200                 goto out;
 201         }
 202         rc = grow_file(ecryptfs_dentry);
 203         if (rc)
 204                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
 205 out:
 206         return rc;
 207 }
 208
 209 /**
 210  * ecryptfs_create
 211  * @dir: The inode of the directory in which to create the file.
 212  * @dentry: The eCryptfs dentry
 213  * @mode: The mode of the new file.
 214  * @nd: nameidata
 215  *
 216  * Creates a new file.
 217  *
 218  * Returns zero on success; non-zero on error condition
 219  */
 220 static int
 221 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 222                 int mode, struct nameidata *nd)
 223 {
 224         int rc;
 225
 226         /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
 227          * the crypt_stat->lower_file (persistent file) */
 228         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
 229         if (unlikely(rc)) {
 230                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 231                                 "lower filesystem\n");
 232                 goto out;
 233         }
 234         /* At this point, a file exists on "disk"; we need to make sure
 235          * that this on disk file is prepared to be an ecryptfs file */
 236         rc = ecryptfs_initialize_file(ecryptfs_dentry);
 237 out:
 238         return rc;
 239 }
 240
 241 /**
 242  * ecryptfs_lookup
 243  * @dir: inode
 244  * @dentry: The dentry
 245  * @nd: nameidata, may be NULL
 246  *
 247  * Find a file on disk. If the file does not exist, then we'll add it to the
 248  * dentry cache and continue on to read it from the disk.
 249  */
 250 static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
 251                                       struct nameidata *nd)
 252 {
 253         int rc = 0;
 254         struct dentry *lower_dir_dentry;
 255         struct dentry *lower_dentry;
 256         struct vfsmount *lower_mnt;
 257         char *encoded_name;
 258         int encoded_namelen;
 259         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 260         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 261         char *page_virt = NULL;
 262         struct inode *lower_inode;
 263         u64 file_size;
 264
 265         lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
 266         dentry->d_op = &ecryptfs_dops;
 267         if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
 268             || (dentry->d_name.len == 2
 269                 && !strcmp(dentry->d_name.name, ".."))) {
 270                 d_drop(dentry);
 271                 goto out;
 272         }
 273         encoded_namelen = ecryptfs_encode_filename(crypt_stat,
 274                                                    dentry->d_name.name,
 275                                                    dentry->d_name.len,
 276                                                    &encoded_name);
 277         if (encoded_namelen < 0) {
 278                 rc = encoded_namelen;
 279                 d_drop(dentry);
 280                 goto out;
 281         }
 282         ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
 283                         "= [%d]\n", encoded_name, encoded_namelen);
 284         lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
 285                                       encoded_namelen - 1);
 286         kfree(encoded_name);
 287         if (IS_ERR(lower_dentry)) {
 288                 ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
 289                 rc = PTR_ERR(lower_dentry);
 290                 d_drop(dentry);
 291                 goto out;
 292         }
 293         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 294         ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
 295                 "d_name.name = [%s]\n", lower_dentry,
 296                 lower_dentry->d_name.name);
 297         lower_inode = lower_dentry->d_inode;
 298         fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
 299         BUG_ON(!atomic_read(&lower_dentry->d_count));
 300         ecryptfs_set_dentry_private(dentry,
 301                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
 302                                                      GFP_KERNEL));
 303         if (!ecryptfs_dentry_to_private(dentry)) {
 304                 rc = -ENOMEM;
 305                 ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
 306                                 "to allocate ecryptfs_dentry_info struct\n");
 307                 goto out_dput;
 308         }
 309         ecryptfs_set_dentry_lower(dentry, lower_dentry);
 310         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
 311         if (!lower_dentry->d_inode) {
 312                 /* We want to add because we couldn't find in lower */
 313                 d_add(dentry, NULL);
 314                 goto out;
 315         }
 316         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
 317         if (rc) {
 318                 ecryptfs_printk(KERN_ERR, "Error interposing\n");
 319                 goto out_dput;
 320         }
 321         if (S_ISDIR(lower_inode->i_mode)) {
 322                 ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
 323                 goto out;
 324         }
 325         if (S_ISLNK(lower_inode->i_mode)) {
 326                 ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
 327                 goto out;
 328         }
 329         if (special_file(lower_inode->i_mode)) {
 330                 ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
 331                 goto out;
 332         }
 333         if (!nd) {
 334                 ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
 335                                 "as we *think* we are about to unlink\n");
 336                 goto out;
 337         }
 338         /* Released in this function */
 339         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
 340                                       GFP_USER);
 341         if (!page_virt) {
 342                 rc = -ENOMEM;
 343                 ecryptfs_printk(KERN_ERR,
 344                                 "Cannot ecryptfs_kmalloc a page\n");
 345                 goto out_dput;
 346         }
 347         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 348         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 349                 ecryptfs_set_default_sizes(crypt_stat);
 350         rc = ecryptfs_read_and_validate_header_region(page_virt,
 351                                                       dentry->d_inode);
 352         if (rc) {
 353                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
 354                 if (rc) {
 355                         printk(KERN_DEBUG "Valid metadata not found in header "
 356                                "region or xattr region; treating file as "
 357                                "unencrypted\n");
 358                         rc = 0;
 359                         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 360                         goto out;
 361                 }
 362                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 363         }
 364         mount_crypt_stat = &ecryptfs_superblock_to_private(
 365                 dentry->d_sb)->mount_crypt_stat;
 366         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
 367                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 368                         file_size = (crypt_stat->num_header_bytes_at_front
 369                                      + i_size_read(lower_dentry->d_inode));
 370                 else
 371                         file_size = i_size_read(lower_dentry->d_inode);
 372         } else {
 373                 memcpy(&file_size, page_virt, sizeof(file_size));
 374                 file_size = be64_to_cpu(file_size);
 375         }
 376         i_size_write(dentry->d_inode, (loff_t)file_size);
 377         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
 378         goto out;
 379
 380 out_dput:
 381         dput(lower_dentry);
 382         d_drop(dentry);
 383 out:
 384         return ERR_PTR(rc);
 385 }
 386
 387 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 388                          struct dentry *new_dentry)
 389 {
 390         struct dentry *lower_old_dentry;
 391         struct dentry *lower_new_dentry;
 392         struct dentry *lower_dir_dentry;
 393         u64 file_size_save;
 394         int rc;
 395
 396         file_size_save = i_size_read(old_dentry->d_inode);
 397         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 398         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 399         dget(lower_old_dentry);
 400         dget(lower_new_dentry);
 401         lower_dir_dentry = lock_parent(lower_new_dentry);
 402         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
 403                       lower_new_dentry);
 404         if (rc || !lower_new_dentry->d_inode)
 405                 goto out_lock;
 406         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
 407         if (rc)
 408                 goto out_lock;
 409         fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
 410         fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
 411         old_dentry->d_inode->i_nlink =
 412                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
 413         i_size_write(new_dentry->d_inode, file_size_save);
 414 out_lock:
 415         unlock_dir(lower_dir_dentry);
 416         dput(lower_new_dentry);
 417         dput(lower_old_dentry);
 418         d_drop(lower_old_dentry);
 419         d_drop(new_dentry);
 420         d_drop(old_dentry);
 421         return rc;
 422 }
 423
 424 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 425 {
 426         int rc = 0;
 427         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 428         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 429
 430         lock_parent(lower_dentry);
 431         rc = vfs_unlink(lower_dir_inode, lower_dentry);
 432         if (rc) {
 433                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 434                 goto out_unlock;
 435         }
 436         fsstack_copy_attr_times(dir, lower_dir_inode);
 437         dentry->d_inode->i_nlink =
 438                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
 439         dentry->d_inode->i_ctime = dir->i_ctime;
 440         d_drop(dentry);
 441 out_unlock:
 442         unlock_parent(lower_dentry);
 443         return rc;
 444 }
 445
 446 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 447                             const char *symname)
 448 {
 449         int rc;
 450         struct dentry *lower_dentry;
 451         struct dentry *lower_dir_dentry;
 452         umode_t mode;
 453         char *encoded_symname;
 454         int encoded_symlen;
 455         struct ecryptfs_crypt_stat *crypt_stat = NULL;
 456
 457         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 458         dget(lower_dentry);
 459         lower_dir_dentry = lock_parent(lower_dentry);
 460         mode = S_IALLUGO;
 461         encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
 462                                                   strlen(symname),
 463                                                   &encoded_symname);
 464         if (encoded_symlen < 0) {
 465                 rc = encoded_symlen;
 466                 goto out_lock;
 467         }
 468         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
 469                          encoded_symname, mode);
 470         kfree(encoded_symname);
 471         if (rc || !lower_dentry->d_inode)
 472                 goto out_lock;
 473         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 474         if (rc)
 475                 goto out_lock;
 476         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 477         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 478 out_lock:
 479         unlock_dir(lower_dir_dentry);
 480         dput(lower_dentry);
 481         if (!dentry->d_inode)
 482                 d_drop(dentry);
 483         return rc;
 484 }
 485
 486 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 487 {
 488         int rc;
 489         struct dentry *lower_dentry;
 490         struct dentry *lower_dir_dentry;
 491
 492         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 493         lower_dir_dentry = lock_parent(lower_dentry);
 494         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
 495         if (rc || !lower_dentry->d_inode)
 496                 goto out;
 497         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 498         if (rc)
 499                 goto out;
 500         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 501         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 502         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 503 out:
 504         unlock_dir(lower_dir_dentry);
 505         if (!dentry->d_inode)
 506                 d_drop(dentry);
 507         return rc;
 508 }
 509
 510 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 511 {
 512         struct dentry *lower_dentry;
 513         struct dentry *lower_dir_dentry;
 514         int rc;
 515
 516         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 517         dget(dentry);
 518         lower_dir_dentry = lock_parent(lower_dentry);
 519         dget(lower_dentry);
 520         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
 521         dput(lower_dentry);
 522         if (!rc)
 523                 d_delete(lower_dentry);
 524         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 525         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
 526         unlock_dir(lower_dir_dentry);
 527         if (!rc)
 528                 d_drop(dentry);
 529         dput(dentry);
 530         return rc;
 531 }
 532
 533 static int
 534 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
 535 {
 536         int rc;
 537         struct dentry *lower_dentry;
 538         struct dentry *lower_dir_dentry;
 539
 540         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 541         lower_dir_dentry = lock_parent(lower_dentry);
 542         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
 543         if (rc || !lower_dentry->d_inode)
 544                 goto out;
 545         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
 546         if (rc)
 547                 goto out;
 548         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
 549         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
 550 out:
 551         unlock_dir(lower_dir_dentry);
 552         if (!dentry->d_inode)
 553                 d_drop(dentry);
 554         return rc;
 555 }
 556
 557 static int
 558 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 559                 struct inode *new_dir, struct dentry *new_dentry)
 560 {
 561         int rc;
 562         struct dentry *lower_old_dentry;
 563         struct dentry *lower_new_dentry;
 564         struct dentry *lower_old_dir_dentry;
 565         struct dentry *lower_new_dir_dentry;
 566
 567         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 568         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 569         dget(lower_old_dentry);
 570         dget(lower_new_dentry);
 571         lower_old_dir_dentry = dget_parent(lower_old_dentry);
 572         lower_new_dir_dentry = dget_parent(lower_new_dentry);
 573         lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 574         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
 575                         lower_new_dir_dentry->d_inode, lower_new_dentry);
 576         if (rc)
 577                 goto out_lock;
 578         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
 579         if (new_dir != old_dir)
 580                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
 581 out_lock:
 582         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 583         dput(lower_new_dentry->d_parent);
 584         dput(lower_old_dentry->d_parent);
 585         dput(lower_new_dentry);
 586         dput(lower_old_dentry);
 587         return rc;
 588 }
 589
 590 static int
 591 ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
 592 {
 593         int rc;
 594         struct dentry *lower_dentry;
 595         char *decoded_name;
 596         char *lower_buf;
 597         mm_segment_t old_fs;
 598         struct ecryptfs_crypt_stat *crypt_stat;
 599
 600         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 601         if (!lower_dentry->d_inode->i_op ||
 602             !lower_dentry->d_inode->i_op->readlink) {
 603                 rc = -EINVAL;
 604                 goto out;
 605         }
 606         /* Released in this function */
 607         lower_buf = kmalloc(bufsiz, GFP_KERNEL);
 608         if (lower_buf == NULL) {
 609                 ecryptfs_printk(KERN_ERR, "Out of memory\n");
 610                 rc = -ENOMEM;
 611                 goto out;
 612         }
 613         old_fs = get_fs();
 614         set_fs(get_ds());
 615         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 616                         "lower_dentry->d_name.name = [%s]\n",
 617                         lower_dentry->d_name.name);
 618         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
 619                                                    (char __user *)lower_buf,
 620                                                    bufsiz);
 621         set_fs(old_fs);
 622         if (rc >= 0) {
 623                 crypt_stat = NULL;
 624                 rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
 625                                               &decoded_name);
 626                 if (rc == -ENOMEM)
 627                         goto out_free_lower_buf;
 628                 if (rc > 0) {
 629                         ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
 630                                         "to userspace: [%*s]\n", rc,
 631                                         decoded_name);
 632                         if (copy_to_user(buf, decoded_name, rc))
 633                                 rc = -EFAULT;
 634                 }
 635                 kfree(decoded_name);
 636                 fsstack_copy_attr_atime(dentry->d_inode,
 637                                         lower_dentry->d_inode);
 638         }
 639 out_free_lower_buf:
 640         kfree(lower_buf);
 641 out:
 642         return rc;
 643 }
 644
 645 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 646 {
 647         char *buf;
 648         int len = PAGE_SIZE, rc;
 649         mm_segment_t old_fs;
 650
 651         /* Released in ecryptfs_put_link(); only release here on error */
 652         buf = kmalloc(len, GFP_KERNEL);
 653         if (!buf) {
 654                 rc = -ENOMEM;
 655                 goto out;
 656         }
 657         old_fs = get_fs();
 658         set_fs(get_ds());
 659         ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
 660                         "dentry->d_name.name = [%s]\n", dentry->d_name.name);
 661         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
 662         buf[rc] = '\0';
 663         set_fs(old_fs);
 664         if (rc < 0)
 665                 goto out_free;
 666         rc = 0;
 667         nd_set_link(nd, buf);
 668         goto out;
 669 out_free:
 670         kfree(buf);
 671 out:
 672         return ERR_PTR(rc);
 673 }
 674
 675 static void
 676 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
 677 {
 678         /* Free the char* */
 679         kfree(nd_get_link(nd));
 680 }
 681
 682 /**
 683  * upper_size_to_lower_size
 684  * @crypt_stat: Crypt_stat associated with file
 685  * @upper_size: Size of the upper file
 686  *
 687  * Calculate the required size of the lower file based on the
 688  * specified size of the upper file. This calculation is based on the
 689  * number of headers in the underlying file and the extent size.
 690  *
 691  * Returns Calculated size of the lower file.
 692  */
 693 static loff_t
 694 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 695                          loff_t upper_size)
 696 {
 697         loff_t lower_size;
 698
 699         lower_size = crypt_stat->num_header_bytes_at_front;
 700         if (upper_size != 0) {
 701                 loff_t num_extents;
 702
 703                 num_extents = upper_size >> crypt_stat->extent_shift;
 704                 if (upper_size & ~crypt_stat->extent_mask)
 705                         num_extents++;
 706                 lower_size += (num_extents * crypt_stat->extent_size);
 707         }
 708         return lower_size;
 709 }
 710
 711 /**
 712  * ecryptfs_truncate
 713  * @dentry: The ecryptfs layer dentry
 714  * @new_length: The length to expand the file to
 715  *
 716  * Function to handle truncations modifying the size of the file. Note
 717  * that the file sizes are interpolated. When expanding, we are simply
 718  * writing strings of 0's out. When truncating, we need to modify the
 719  * underlying file size according to the page index interpolations.
 720  *
 721  * Returns zero on success; non-zero otherwise
 722  */
 723 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 724 {
 725         int rc = 0;
 726         struct inode *inode = dentry->d_inode;
 727         struct dentry *lower_dentry;
 728         struct file fake_ecryptfs_file;
 729         struct ecryptfs_crypt_stat *crypt_stat;
 730         loff_t i_size = i_size_read(inode);
 731         loff_t lower_size_before_truncate;
 732         loff_t lower_size_after_truncate;
 733
 734         if (unlikely((new_length == i_size)))
 735                 goto out;
 736         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 737         /* Set up a fake ecryptfs file, this is used to interface with
 738          * the file in the underlying filesystem so that the
 739          * truncation has an effect there as well. */
 740         memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
 741         fake_ecryptfs_file.f_path.dentry = dentry;
 742         /* Released at out_free: label */
 743         ecryptfs_set_file_private(&fake_ecryptfs_file,
 744                                   kmem_cache_alloc(ecryptfs_file_info_cache,
 745                                                    GFP_KERNEL));
 746         if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
 747                 rc = -ENOMEM;
 748                 goto out;
 749         }
 750         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 751         ecryptfs_set_file_lower(
 752                 &fake_ecryptfs_file,
 753                 ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
 754         /* Switch on growing or shrinking file */
 755         if (new_length > i_size) {
 756                 char zero[] = { 0x00 };
 757
 758                 /* Write a single 0 at the last position of the file;
 759                  * this triggers code that will fill in 0's throughout
 760                  * the intermediate portion of the previous end of the
 761                  * file and the new and of the file */
 762                 rc = ecryptfs_write(&fake_ecryptfs_file, zero,
 763                                     (new_length - 1), 1);
 764         } else { /* new_length < i_size_read(inode) */
 765                 /* We're chopping off all the pages down do the page
 766                  * in which new_length is located. Fill in the end of
 767                  * that page from (new_length & ~PAGE_CACHE_MASK) to
 768                  * PAGE_CACHE_SIZE with zeros. */
 769                 size_t num_zeros = (PAGE_CACHE_SIZE
 770                                     - (new_length & ~PAGE_CACHE_MASK));
 771
 772                 if (num_zeros) {
 773                         char *zeros_virt;
 774
 775                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 776                         if (!zeros_virt) {
 777                                 rc = -ENOMEM;
 778                                 goto out_free;
 779                         }
 780                         rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
 781                                             new_length, num_zeros);
 782                         kfree(zeros_virt);
 783                         if (rc) {
 784                                 printk(KERN_ERR "Error attempting to zero out "
 785                                        "the remainder of the end page on "
 786                                        "reducing truncate; rc = [%d]\n", rc);
 787                                 goto out_free;
 788                         }
 789                 }
 790                 vmtruncate(inode, new_length);
 791                 rc = ecryptfs_write_inode_size_to_metadata(inode);
 792                 if (rc) {
 793                         printk(KERN_ERR "Problem with "
 794                                "ecryptfs_write_inode_size_to_metadata; "
 795                                "rc = [%d]\n", rc);
 796                         goto out_free;
 797                 }
 798                 /* We are reducing the size of the ecryptfs file, and need to
 799                  * know if we need to reduce the size of the lower file. */
 800                 lower_size_before_truncate =
 801                     upper_size_to_lower_size(crypt_stat, i_size);
 802                 lower_size_after_truncate =
 803                     upper_size_to_lower_size(crypt_stat, new_length);
 804                 if (lower_size_after_truncate < lower_size_before_truncate)
 805                         vmtruncate(lower_dentry->d_inode,
 806                                    lower_size_after_truncate);
 807         }
 808 out_free:
 809         if (ecryptfs_file_to_private(&fake_ecryptfs_file))
 810                 kmem_cache_free(ecryptfs_file_info_cache,
 811                                 ecryptfs_file_to_private(&fake_ecryptfs_file));
 812 out:
 813         return rc;
 814 }
 815
 816 static int
 817 ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
 818 {
 819         int rc;
 820
 821         if (nd) {
 822                 struct vfsmount *vfsmnt_save = nd->mnt;
 823                 struct dentry *dentry_save = nd->dentry;
 824
 825                 nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
 826                 nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
 827                 rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
 828                 nd->mnt = vfsmnt_save;
 829                 nd->dentry = dentry_save;
 830         } else
 831                 rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
 832         return rc;
 833 }
 834
 835 /**
 836  * ecryptfs_setattr
 837  * @dentry: dentry handle to the inode to modify
 838  * @ia: Structure with flags of what to change and values
 839  *
 840  * Updates the metadata of an inode. If the update is to the size
 841  * i.e. truncation, then ecryptfs_truncate will handle the size modification
 842  * of both the ecryptfs inode and the lower inode.
 843  *
 844  * All other metadata changes will be passed right to the lower filesystem,
 845  * and we will just update our inode to look like the lower.
 846  */
 847 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 848 {
 849         int rc = 0;
 850         struct dentry *lower_dentry;
 851         struct inode *inode;
 852         struct inode *lower_inode;
 853         struct ecryptfs_crypt_stat *crypt_stat;
 854
 855         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
 856         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
 857                 ecryptfs_init_crypt_stat(crypt_stat);
 858         inode = dentry->d_inode;
 859         lower_inode = ecryptfs_inode_to_lower(inode);
 860         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 861         mutex_lock(&crypt_stat->cs_mutex);
 862         if (S_ISDIR(dentry->d_inode->i_mode))
 863                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 864         else if (S_ISREG(dentry->d_inode->i_mode)
 865                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 866                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 867                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 868
 869                 mount_crypt_stat = &ecryptfs_superblock_to_private(
 870                         dentry->d_sb)->mount_crypt_stat;
 871                 rc = ecryptfs_read_metadata(dentry);
 872                 if (rc) {
 873                         if (!(mount_crypt_stat->flags
 874                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 875                                 rc = -EIO;
 876                                 printk(KERN_WARNING "Either the lower file "
 877                                        "is not in a valid eCryptfs format, "
 878                                        "or the key could not be retrieved. "
 879                                        "Plaintext passthrough mode is not "
 880                                        "enabled; returning -EIO\n");
 881                                 mutex_unlock(&crypt_stat->cs_mutex);
 882                                 goto out;
 883                         }
 884                         rc = 0;
 885                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 886                         mutex_unlock(&crypt_stat->cs_mutex);
 887                         goto out;
 888                 }
 889         }
 890         mutex_unlock(&crypt_stat->cs_mutex);
 891         if (ia->ia_valid & ATTR_SIZE) {
 892                 ecryptfs_printk(KERN_DEBUG,
 893                                 "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
 894                                 ia->ia_valid, ATTR_SIZE);
 895                 rc = ecryptfs_truncate(dentry, ia->ia_size);
 896                 /* ecryptfs_truncate handles resizing of the lower file */
 897                 ia->ia_valid &= ~ATTR_SIZE;
 898                 ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
 899                                 ia->ia_valid);
 900                 if (rc < 0)
 901                         goto out;
 902         }
 903
 904         /*
 905          * mode change is for clearing setuid/setgid bits. Allow lower fs
 906          * to interpret this in its own way.
 907          */
 908         if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 909                 ia->ia_valid &= ~ATTR_MODE;
 910
 911         rc = notify_change(lower_dentry, ia);
 912 out:
 913         fsstack_copy_attr_all(inode, lower_inode, NULL);
 914         return rc;
 915 }
 916
 917 int
 918 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
 919                   size_t size, int flags)
 920 {
 921         int rc = 0;
 922         struct dentry *lower_dentry;
 923
 924         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 925         if (!lower_dentry->d_inode->i_op->setxattr) {
 926                 rc = -ENOSYS;
 927                 goto out;
 928         }
 929         mutex_lock(&lower_dentry->d_inode->i_mutex);
 930         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
 931                                                    size, flags);
 932         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 933 out:
 934         return rc;
 935 }
 936
 937 ssize_t
 938 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
 939                         void *value, size_t size)
 940 {
 941         int rc = 0;
 942
 943         if (!lower_dentry->d_inode->i_op->getxattr) {
 944                 rc = -ENOSYS;
 945                 goto out;
 946         }
 947         mutex_lock(&lower_dentry->d_inode->i_mutex);
 948         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
 949                                                    size);
 950         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 951 out:
 952         return rc;
 953 }
 954
 955 static ssize_t
 956 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
 957                   size_t size)
 958 {
 959         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
 960                                        value, size);
 961 }
 962
 963 static ssize_t
 964 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
 965 {
 966         int rc = 0;
 967         struct dentry *lower_dentry;
 968
 969         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 970         if (!lower_dentry->d_inode->i_op->listxattr) {
 971                 rc = -ENOSYS;
 972                 goto out;
 973         }
 974         mutex_lock(&lower_dentry->d_inode->i_mutex);
 975         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
 976         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 977 out:
 978         return rc;
 979 }
 980
 981 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
 982 {
 983         int rc = 0;
 984         struct dentry *lower_dentry;
 985
 986         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 987         if (!lower_dentry->d_inode->i_op->removexattr) {
 988                 rc = -ENOSYS;
 989                 goto out;
 990         }
 991         mutex_lock(&lower_dentry->d_inode->i_mutex);
 992         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
 993         mutex_unlock(&lower_dentry->d_inode->i_mutex);
 994 out:
 995         return rc;
 996 }
 997
 998 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
 999 {
1000         if ((ecryptfs_inode_to_lower(inode)
1001              == (struct inode *)candidate_lower_inode))
1002                 return 1;
1003         else
1004                 return 0;
1005 }
1006
1007 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1008 {
1009         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1010         return 0;
1011 }
1012
1013 const struct inode_operations ecryptfs_symlink_iops = {
1014         .readlink = ecryptfs_readlink,
1015         .follow_link = ecryptfs_follow_link,
1016         .put_link = ecryptfs_put_link,
1017         .permission = ecryptfs_permission,
1018         .setattr = ecryptfs_setattr,
1019         .setxattr = ecryptfs_setxattr,
1020         .getxattr = ecryptfs_getxattr,
1021         .listxattr = ecryptfs_listxattr,
1022         .removexattr = ecryptfs_removexattr
1023 };
1024
1025 const struct inode_operations ecryptfs_dir_iops = {
1026         .create = ecryptfs_create,
1027         .lookup = ecryptfs_lookup,
1028         .link = ecryptfs_link,
1029         .unlink = ecryptfs_unlink,
1030         .symlink = ecryptfs_symlink,
1031         .mkdir = ecryptfs_mkdir,
1032         .rmdir = ecryptfs_rmdir,
1033         .mknod = ecryptfs_mknod,
1034         .rename = ecryptfs_rename,
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 const struct inode_operations ecryptfs_main_iops = {
1044         .permission = ecryptfs_permission,
1045         .setattr = ecryptfs_setattr,
1046         .setxattr = ecryptfs_setxattr,
1047         .getxattr = ecryptfs_getxattr,
1048         .listxattr = ecryptfs_listxattr,
1049         .removexattr = ecryptfs_removexattr
1050 };