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/fs_stack.h>
  33#include <linux/slab.h>
  34#include <linux/xattr.h>
  35#include <asm/unaligned.h>
  36#include "ecryptfs_kernel.h"
  37
  38static struct dentry *lock_parent(struct dentry *dentry)
  39{
  40	struct dentry *dir;
  41
  42	dir = dget_parent(dentry);
  43	inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
  44	return dir;
  45}
  46
  47static void unlock_dir(struct dentry *dir)
  48{
  49	inode_unlock(d_inode(dir));
  50	dput(dir);
  51}
  52
  53static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
  54{
  55	return ecryptfs_inode_to_lower(inode) == lower_inode;
  56}
  57
  58static int ecryptfs_inode_set(struct inode *inode, void *opaque)
  59{
  60	struct inode *lower_inode = opaque;
  61
  62	ecryptfs_set_inode_lower(inode, lower_inode);
  63	fsstack_copy_attr_all(inode, lower_inode);
  64	/* i_size will be overwritten for encrypted regular files */
  65	fsstack_copy_inode_size(inode, lower_inode);
  66	inode->i_ino = lower_inode->i_ino;
  67	inode->i_version++;
  68	inode->i_mapping->a_ops = &ecryptfs_aops;
  69
  70	if (S_ISLNK(inode->i_mode))
  71		inode->i_op = &ecryptfs_symlink_iops;
  72	else if (S_ISDIR(inode->i_mode))
  73		inode->i_op = &ecryptfs_dir_iops;
  74	else
  75		inode->i_op = &ecryptfs_main_iops;
  76
  77	if (S_ISDIR(inode->i_mode))
  78		inode->i_fop = &ecryptfs_dir_fops;
  79	else if (special_file(inode->i_mode))
  80		init_special_inode(inode, inode->i_mode, inode->i_rdev);
  81	else
  82		inode->i_fop = &ecryptfs_main_fops;
  83
  84	return 0;
  85}
  86
  87static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
  88					  struct super_block *sb)
  89{
  90	struct inode *inode;
  91
  92	if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
  93		return ERR_PTR(-EXDEV);
  94	if (!igrab(lower_inode))
  95		return ERR_PTR(-ESTALE);
  96	inode = iget5_locked(sb, (unsigned long)lower_inode,
  97			     ecryptfs_inode_test, ecryptfs_inode_set,
  98			     lower_inode);
  99	if (!inode) {
 100		iput(lower_inode);
 101		return ERR_PTR(-EACCES);
 102	}
 103	if (!(inode->i_state & I_NEW))
 104		iput(lower_inode);
 105
 106	return inode;
 107}
 108
 109struct inode *ecryptfs_get_inode(struct inode *lower_inode,
 110				 struct super_block *sb)
 111{
 112	struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
 113
 114	if (!IS_ERR(inode) && (inode->i_state & I_NEW))
 115		unlock_new_inode(inode);
 116
 117	return inode;
 118}
 119
 120/**
 121 * ecryptfs_interpose
 122 * @lower_dentry: Existing dentry in the lower filesystem
 123 * @dentry: ecryptfs' dentry
 124 * @sb: ecryptfs's super_block
 125 *
 126 * Interposes upper and lower dentries.
 127 *
 128 * Returns zero on success; non-zero otherwise
 129 */
 130static int ecryptfs_interpose(struct dentry *lower_dentry,
 131			      struct dentry *dentry, struct super_block *sb)
 132{
 133	struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
 134
 135	if (IS_ERR(inode))
 136		return PTR_ERR(inode);
 137	d_instantiate(dentry, inode);
 138
 139	return 0;
 140}
 141
 142static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 143			      struct inode *inode)
 144{
 145	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 146	struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
 147	struct dentry *lower_dir_dentry;
 148	int rc;
 149
 150	dget(lower_dentry);
 151	lower_dir_dentry = lock_parent(lower_dentry);
 152	rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
 153	if (rc) {
 154		printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 155		goto out_unlock;
 156	}
 157	fsstack_copy_attr_times(dir, lower_dir_inode);
 158	set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 159	inode->i_ctime = dir->i_ctime;
 160	d_drop(dentry);
 161out_unlock:
 162	unlock_dir(lower_dir_dentry);
 163	dput(lower_dentry);
 164	return rc;
 165}
 166
 167/**
 168 * ecryptfs_do_create
 169 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 170 * @ecryptfs_dentry: New file's dentry in ecryptfs
 171 * @mode: The mode of the new file
 172 *
 173 * Creates the underlying file and the eCryptfs inode which will link to
 174 * it. It will also update the eCryptfs directory inode to mimic the
 175 * stat of the lower directory inode.
 176 *
 177 * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
 178 */
 179static struct inode *
 180ecryptfs_do_create(struct inode *directory_inode,
 181		   struct dentry *ecryptfs_dentry, umode_t mode)
 182{
 183	int rc;
 184	struct dentry *lower_dentry;
 185	struct dentry *lower_dir_dentry;
 186	struct inode *inode;
 187
 188	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 189	lower_dir_dentry = lock_parent(lower_dentry);
 190	rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
 191	if (rc) {
 192		printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 193		       "rc = [%d]\n", __func__, rc);
 194		inode = ERR_PTR(rc);
 195		goto out_lock;
 196	}
 197	inode = __ecryptfs_get_inode(d_inode(lower_dentry),
 198				     directory_inode->i_sb);
 199	if (IS_ERR(inode)) {
 200		vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
 201		goto out_lock;
 202	}
 203	fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
 204	fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
 205out_lock:
 206	unlock_dir(lower_dir_dentry);
 207	return inode;
 208}
 209
 210/**
 211 * ecryptfs_initialize_file
 212 *
 213 * Cause the file to be changed from a basic empty file to an ecryptfs
 214 * file with a header and first data page.
 215 *
 216 * Returns zero on success
 217 */
 218int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
 219			     struct inode *ecryptfs_inode)
 220{
 221	struct ecryptfs_crypt_stat *crypt_stat =
 222		&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
 223	int rc = 0;
 224
 225	if (S_ISDIR(ecryptfs_inode->i_mode)) {
 226		ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 227		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 228		goto out;
 229	}
 230	ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
 231	rc = ecryptfs_new_file_context(ecryptfs_inode);
 232	if (rc) {
 233		ecryptfs_printk(KERN_ERR, "Error creating new file "
 234				"context; rc = [%d]\n", rc);
 235		goto out;
 236	}
 237	rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
 238	if (rc) {
 239		printk(KERN_ERR "%s: Error attempting to initialize "
 240			"the lower file for the dentry with name "
 241			"[%pd]; rc = [%d]\n", __func__,
 242			ecryptfs_dentry, rc);
 243		goto out;
 244	}
 245	rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
 246	if (rc)
 247		printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
 248	ecryptfs_put_lower_file(ecryptfs_inode);
 249out:
 250	return rc;
 251}
 252
 253/**
 254 * ecryptfs_create
 255 * @dir: The inode of the directory in which to create the file.
 256 * @dentry: The eCryptfs dentry
 257 * @mode: The mode of the new file.
 258 *
 259 * Creates a new file.
 260 *
 261 * Returns zero on success; non-zero on error condition
 262 */
 263static int
 264ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 265		umode_t mode, bool excl)
 266{
 267	struct inode *ecryptfs_inode;
 268	int rc;
 269
 270	ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
 271					    mode);
 272	if (IS_ERR(ecryptfs_inode)) {
 273		ecryptfs_printk(KERN_WARNING, "Failed to create file in"
 274				"lower filesystem\n");
 275		rc = PTR_ERR(ecryptfs_inode);
 276		goto out;
 277	}
 278	/* At this point, a file exists on "disk"; we need to make sure
 279	 * that this on disk file is prepared to be an ecryptfs file */
 280	rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
 281	if (rc) {
 282		ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
 283				   ecryptfs_inode);
 284		iget_failed(ecryptfs_inode);
 285		goto out;
 286	}
 287	unlock_new_inode(ecryptfs_inode);
 288	d_instantiate(ecryptfs_dentry, ecryptfs_inode);
 289out:
 290	return rc;
 291}
 292
 293static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
 294{
 295	struct ecryptfs_crypt_stat *crypt_stat;
 296	int rc;
 297
 298	rc = ecryptfs_get_lower_file(dentry, inode);
 299	if (rc) {
 300		printk(KERN_ERR "%s: Error attempting to initialize "
 301			"the lower file for the dentry with name "
 302			"[%pd]; rc = [%d]\n", __func__,
 303			dentry, rc);
 304		return rc;
 305	}
 306
 307	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 308	/* TODO: lock for crypt_stat comparison */
 309	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
 310		ecryptfs_set_default_sizes(crypt_stat);
 311
 312	rc = ecryptfs_read_and_validate_header_region(inode);
 313	ecryptfs_put_lower_file(inode);
 314	if (rc) {
 315		rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
 316		if (!rc)
 317			crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 318	}
 319
 320	/* Must return 0 to allow non-eCryptfs files to be looked up, too */
 321	return 0;
 322}
 323
 324/**
 325 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 326 */
 327static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
 328				     struct dentry *lower_dentry)
 
 329{
 330	struct inode *inode, *lower_inode = d_inode(lower_dentry);
 331	struct ecryptfs_dentry_info *dentry_info;
 332	struct vfsmount *lower_mnt;
 333	int rc = 0;
 334
 335	dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 336	if (!dentry_info) {
 337		printk(KERN_ERR "%s: Out of memory whilst attempting "
 338		       "to allocate ecryptfs_dentry_info struct\n",
 339			__func__);
 340		dput(lower_dentry);
 341		return ERR_PTR(-ENOMEM);
 342	}
 343
 344	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
 345	fsstack_copy_attr_atime(d_inode(dentry->d_parent),
 346				d_inode(lower_dentry->d_parent));
 347	BUG_ON(!d_count(lower_dentry));
 348
 349	ecryptfs_set_dentry_private(dentry, dentry_info);
 350	dentry_info->lower_path.mnt = lower_mnt;
 351	dentry_info->lower_path.dentry = lower_dentry;
 352
 353	if (d_really_is_negative(lower_dentry)) {
 354		/* We want to add because we couldn't find in lower */
 355		d_add(dentry, NULL);
 356		return NULL;
 357	}
 358	inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
 359	if (IS_ERR(inode)) {
 360		printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
 361		       __func__, PTR_ERR(inode));
 362		return ERR_CAST(inode);
 363	}
 364	if (S_ISREG(inode->i_mode)) {
 365		rc = ecryptfs_i_size_read(dentry, inode);
 366		if (rc) {
 367			make_bad_inode(inode);
 368			return ERR_PTR(rc);
 369		}
 370	}
 371
 372	if (inode->i_state & I_NEW)
 373		unlock_new_inode(inode);
 374	return d_splice_alias(inode, dentry);
 
 
 375}
 376
 377/**
 378 * ecryptfs_lookup
 379 * @ecryptfs_dir_inode: The eCryptfs directory inode
 380 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 381 * @flags: lookup flags
 382 *
 383 * Find a file on disk. If the file does not exist, then we'll add it to the
 384 * dentry cache and continue on to read it from the disk.
 385 */
 386static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
 387				      struct dentry *ecryptfs_dentry,
 388				      unsigned int flags)
 389{
 390	char *encrypted_and_encoded_name = NULL;
 391	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 
 392	struct dentry *lower_dir_dentry, *lower_dentry;
 393	const char *name = ecryptfs_dentry->d_name.name;
 394	size_t len = ecryptfs_dentry->d_name.len;
 395	struct dentry *res;
 396	int rc = 0;
 397
 398	lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
 399
 
 
 
 
 
 
 
 
 
 
 
 400	mount_crypt_stat = &ecryptfs_superblock_to_private(
 401				ecryptfs_dentry->d_sb)->mount_crypt_stat;
 402	if (mount_crypt_stat
 403	    && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
 404		rc = ecryptfs_encrypt_and_encode_filename(
 405			&encrypted_and_encoded_name, &len,
 406			mount_crypt_stat, name, len);
 407		if (rc) {
 408			printk(KERN_ERR "%s: Error attempting to encrypt and encode "
 409			       "filename; rc = [%d]\n", __func__, rc);
 410			return ERR_PTR(rc);
 411		}
 412		name = encrypted_and_encoded_name;
 
 413	}
 414
 415	lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
 
 416	if (IS_ERR(lower_dentry)) {
 
 417		ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
 418				"[%ld] on lower_dentry = [%s]\n", __func__,
 419				PTR_ERR(lower_dentry),
 420				name);
 421		res = ERR_CAST(lower_dentry);
 422	} else {
 423		res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
 424	}
 
 
 
 
 425	kfree(encrypted_and_encoded_name);
 426	return res;
 427}
 428
 429static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 430			 struct dentry *new_dentry)
 431{
 432	struct dentry *lower_old_dentry;
 433	struct dentry *lower_new_dentry;
 434	struct dentry *lower_dir_dentry;
 435	u64 file_size_save;
 436	int rc;
 437
 438	file_size_save = i_size_read(d_inode(old_dentry));
 439	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 440	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 441	dget(lower_old_dentry);
 442	dget(lower_new_dentry);
 443	lower_dir_dentry = lock_parent(lower_new_dentry);
 444	rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
 445		      lower_new_dentry, NULL);
 446	if (rc || d_really_is_negative(lower_new_dentry))
 447		goto out_lock;
 448	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
 449	if (rc)
 450		goto out_lock;
 451	fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 452	fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 453	set_nlink(d_inode(old_dentry),
 454		  ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 455	i_size_write(d_inode(new_dentry), file_size_save);
 456out_lock:
 457	unlock_dir(lower_dir_dentry);
 458	dput(lower_new_dentry);
 459	dput(lower_old_dentry);
 460	return rc;
 461}
 462
 463static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 464{
 465	return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 466}
 467
 468static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
 469			    const char *symname)
 470{
 471	int rc;
 472	struct dentry *lower_dentry;
 473	struct dentry *lower_dir_dentry;
 474	char *encoded_symname;
 475	size_t encoded_symlen;
 476	struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 477
 478	lower_dentry = ecryptfs_dentry_to_lower(dentry);
 479	dget(lower_dentry);
 480	lower_dir_dentry = lock_parent(lower_dentry);
 481	mount_crypt_stat = &ecryptfs_superblock_to_private(
 482		dir->i_sb)->mount_crypt_stat;
 483	rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
 484						  &encoded_symlen,
 485						  mount_crypt_stat, symname,
 486						  strlen(symname));
 487	if (rc)
 488		goto out_lock;
 489	rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
 490			 encoded_symname);
 491	kfree(encoded_symname);
 492	if (rc || d_really_is_negative(lower_dentry))
 493		goto out_lock;
 494	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 495	if (rc)
 496		goto out_lock;
 497	fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 498	fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 499out_lock:
 500	unlock_dir(lower_dir_dentry);
 501	dput(lower_dentry);
 502	if (d_really_is_negative(dentry))
 503		d_drop(dentry);
 504	return rc;
 505}
 506
 507static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 508{
 509	int rc;
 510	struct dentry *lower_dentry;
 511	struct dentry *lower_dir_dentry;
 512
 513	lower_dentry = ecryptfs_dentry_to_lower(dentry);
 514	lower_dir_dentry = lock_parent(lower_dentry);
 515	rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
 516	if (rc || d_really_is_negative(lower_dentry))
 517		goto out;
 518	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 519	if (rc)
 520		goto out;
 521	fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 522	fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 523	set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 524out:
 525	unlock_dir(lower_dir_dentry);
 526	if (d_really_is_negative(dentry))
 527		d_drop(dentry);
 528	return rc;
 529}
 530
 531static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 532{
 533	struct dentry *lower_dentry;
 534	struct dentry *lower_dir_dentry;
 535	int rc;
 536
 537	lower_dentry = ecryptfs_dentry_to_lower(dentry);
 538	dget(dentry);
 539	lower_dir_dentry = lock_parent(lower_dentry);
 540	dget(lower_dentry);
 541	rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
 542	dput(lower_dentry);
 543	if (!rc && d_really_is_positive(dentry))
 544		clear_nlink(d_inode(dentry));
 545	fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 546	set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
 547	unlock_dir(lower_dir_dentry);
 548	if (!rc)
 549		d_drop(dentry);
 550	dput(dentry);
 551	return rc;
 552}
 553
 554static int
 555ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 556{
 557	int rc;
 558	struct dentry *lower_dentry;
 559	struct dentry *lower_dir_dentry;
 560
 561	lower_dentry = ecryptfs_dentry_to_lower(dentry);
 562	lower_dir_dentry = lock_parent(lower_dentry);
 563	rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
 564	if (rc || d_really_is_negative(lower_dentry))
 565		goto out;
 566	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
 567	if (rc)
 568		goto out;
 569	fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
 570	fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
 571out:
 572	unlock_dir(lower_dir_dentry);
 573	if (d_really_is_negative(dentry))
 574		d_drop(dentry);
 575	return rc;
 576}
 577
 578static int
 579ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 580		struct inode *new_dir, struct dentry *new_dentry,
 581		unsigned int flags)
 582{
 583	int rc;
 584	struct dentry *lower_old_dentry;
 585	struct dentry *lower_new_dentry;
 586	struct dentry *lower_old_dir_dentry;
 587	struct dentry *lower_new_dir_dentry;
 588	struct dentry *trap = NULL;
 589	struct inode *target_inode;
 590
 591	if (flags)
 592		return -EINVAL;
 593
 594	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
 595	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
 596	dget(lower_old_dentry);
 597	dget(lower_new_dentry);
 598	lower_old_dir_dentry = dget_parent(lower_old_dentry);
 599	lower_new_dir_dentry = dget_parent(lower_new_dentry);
 600	target_inode = d_inode(new_dentry);
 601	trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 602	/* source should not be ancestor of target */
 603	if (trap == lower_old_dentry) {
 604		rc = -EINVAL;
 605		goto out_lock;
 606	}
 607	/* target should not be ancestor of source */
 608	if (trap == lower_new_dentry) {
 609		rc = -ENOTEMPTY;
 610		goto out_lock;
 611	}
 612	rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
 613			d_inode(lower_new_dir_dentry), lower_new_dentry,
 614			NULL, 0);
 615	if (rc)
 616		goto out_lock;
 617	if (target_inode)
 618		fsstack_copy_attr_all(target_inode,
 619				      ecryptfs_inode_to_lower(target_inode));
 620	fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
 621	if (new_dir != old_dir)
 622		fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 623out_lock:
 624	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
 625	dput(lower_new_dir_dentry);
 626	dput(lower_old_dir_dentry);
 627	dput(lower_new_dentry);
 628	dput(lower_old_dentry);
 629	return rc;
 630}
 631
 632static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 633{
 634	DEFINE_DELAYED_CALL(done);
 635	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 636	const char *link;
 637	char *buf;
 
 638	int rc;
 639
 640	link = vfs_get_link(lower_dentry, &done);
 641	if (IS_ERR(link))
 642		return ERR_CAST(link);
 643
 
 
 
 
 
 
 
 644	rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
 645						  link, strlen(link));
 646	do_delayed_call(&done);
 647	if (rc)
 648		return ERR_PTR(rc);
 649
 650	return buf;
 651}
 652
 653static const char *ecryptfs_get_link(struct dentry *dentry,
 654				     struct inode *inode,
 655				     struct delayed_call *done)
 656{
 657	size_t len;
 658	char *buf;
 659
 660	if (!dentry)
 661		return ERR_PTR(-ECHILD);
 662
 663	buf = ecryptfs_readlink_lower(dentry, &len);
 664	if (IS_ERR(buf))
 665		return buf;
 666	fsstack_copy_attr_atime(d_inode(dentry),
 667				d_inode(ecryptfs_dentry_to_lower(dentry)));
 668	buf[len] = '\0';
 669	set_delayed_call(done, kfree_link, buf);
 670	return buf;
 671}
 672
 673/**
 674 * upper_size_to_lower_size
 675 * @crypt_stat: Crypt_stat associated with file
 676 * @upper_size: Size of the upper file
 677 *
 678 * Calculate the required size of the lower file based on the
 679 * specified size of the upper file. This calculation is based on the
 680 * number of headers in the underlying file and the extent size.
 681 *
 682 * Returns Calculated size of the lower file.
 683 */
 684static loff_t
 685upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
 686			 loff_t upper_size)
 687{
 688	loff_t lower_size;
 689
 690	lower_size = ecryptfs_lower_header_size(crypt_stat);
 691	if (upper_size != 0) {
 692		loff_t num_extents;
 693
 694		num_extents = upper_size >> crypt_stat->extent_shift;
 695		if (upper_size & ~crypt_stat->extent_mask)
 696			num_extents++;
 697		lower_size += (num_extents * crypt_stat->extent_size);
 698	}
 699	return lower_size;
 700}
 701
 702/**
 703 * truncate_upper
 704 * @dentry: The ecryptfs layer dentry
 705 * @ia: Address of the ecryptfs inode's attributes
 706 * @lower_ia: Address of the lower inode's attributes
 707 *
 708 * Function to handle truncations modifying the size of the file. Note
 709 * that the file sizes are interpolated. When expanding, we are simply
 710 * writing strings of 0's out. When truncating, we truncate the upper
 711 * inode and update the lower_ia according to the page index
 712 * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
 713 * the caller must use lower_ia in a call to notify_change() to perform
 714 * the truncation of the lower inode.
 715 *
 716 * Returns zero on success; non-zero otherwise
 717 */
 718static int truncate_upper(struct dentry *dentry, struct iattr *ia,
 719			  struct iattr *lower_ia)
 720{
 721	int rc = 0;
 722	struct inode *inode = d_inode(dentry);
 723	struct ecryptfs_crypt_stat *crypt_stat;
 724	loff_t i_size = i_size_read(inode);
 725	loff_t lower_size_before_truncate;
 726	loff_t lower_size_after_truncate;
 727
 728	if (unlikely((ia->ia_size == i_size))) {
 729		lower_ia->ia_valid &= ~ATTR_SIZE;
 730		return 0;
 731	}
 732	rc = ecryptfs_get_lower_file(dentry, inode);
 733	if (rc)
 734		return rc;
 735	crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 736	/* Switch on growing or shrinking file */
 737	if (ia->ia_size > i_size) {
 738		char zero[] = { 0x00 };
 739
 740		lower_ia->ia_valid &= ~ATTR_SIZE;
 741		/* Write a single 0 at the last position of the file;
 742		 * this triggers code that will fill in 0's throughout
 743		 * the intermediate portion of the previous end of the
 744		 * file and the new and of the file */
 745		rc = ecryptfs_write(inode, zero,
 746				    (ia->ia_size - 1), 1);
 747	} else { /* ia->ia_size < i_size_read(inode) */
 748		/* We're chopping off all the pages down to the page
 749		 * in which ia->ia_size is located. Fill in the end of
 750		 * that page from (ia->ia_size & ~PAGE_MASK) to
 751		 * PAGE_SIZE with zeros. */
 752		size_t num_zeros = (PAGE_SIZE
 753				    - (ia->ia_size & ~PAGE_MASK));
 754
 755		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
 756			truncate_setsize(inode, ia->ia_size);
 757			lower_ia->ia_size = ia->ia_size;
 758			lower_ia->ia_valid |= ATTR_SIZE;
 759			goto out;
 760		}
 761		if (num_zeros) {
 762			char *zeros_virt;
 763
 764			zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
 765			if (!zeros_virt) {
 766				rc = -ENOMEM;
 767				goto out;
 768			}
 769			rc = ecryptfs_write(inode, zeros_virt,
 770					    ia->ia_size, num_zeros);
 771			kfree(zeros_virt);
 772			if (rc) {
 773				printk(KERN_ERR "Error attempting to zero out "
 774				       "the remainder of the end page on "
 775				       "reducing truncate; rc = [%d]\n", rc);
 776				goto out;
 777			}
 778		}
 779		truncate_setsize(inode, ia->ia_size);
 780		rc = ecryptfs_write_inode_size_to_metadata(inode);
 781		if (rc) {
 782			printk(KERN_ERR	"Problem with "
 783			       "ecryptfs_write_inode_size_to_metadata; "
 784			       "rc = [%d]\n", rc);
 785			goto out;
 786		}
 787		/* We are reducing the size of the ecryptfs file, and need to
 788		 * know if we need to reduce the size of the lower file. */
 789		lower_size_before_truncate =
 790		    upper_size_to_lower_size(crypt_stat, i_size);
 791		lower_size_after_truncate =
 792		    upper_size_to_lower_size(crypt_stat, ia->ia_size);
 793		if (lower_size_after_truncate < lower_size_before_truncate) {
 794			lower_ia->ia_size = lower_size_after_truncate;
 795			lower_ia->ia_valid |= ATTR_SIZE;
 796		} else
 797			lower_ia->ia_valid &= ~ATTR_SIZE;
 798	}
 799out:
 800	ecryptfs_put_lower_file(inode);
 801	return rc;
 802}
 803
 804static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
 805{
 806	struct ecryptfs_crypt_stat *crypt_stat;
 807	loff_t lower_oldsize, lower_newsize;
 808
 809	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 810	lower_oldsize = upper_size_to_lower_size(crypt_stat,
 811						 i_size_read(inode));
 812	lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
 813	if (lower_newsize > lower_oldsize) {
 814		/*
 815		 * The eCryptfs inode and the new *lower* size are mixed here
 816		 * because we may not have the lower i_mutex held and/or it may
 817		 * not be appropriate to call inode_newsize_ok() with inodes
 818		 * from other filesystems.
 819		 */
 820		return inode_newsize_ok(inode, lower_newsize);
 821	}
 822
 823	return 0;
 824}
 825
 826/**
 827 * ecryptfs_truncate
 828 * @dentry: The ecryptfs layer dentry
 829 * @new_length: The length to expand the file to
 830 *
 831 * Simple function that handles the truncation of an eCryptfs inode and
 832 * its corresponding lower inode.
 833 *
 834 * Returns zero on success; non-zero otherwise
 835 */
 836int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 837{
 838	struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
 839	struct iattr lower_ia = { .ia_valid = 0 };
 840	int rc;
 841
 842	rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
 843	if (rc)
 844		return rc;
 845
 846	rc = truncate_upper(dentry, &ia, &lower_ia);
 847	if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
 848		struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
 849
 850		inode_lock(d_inode(lower_dentry));
 851		rc = notify_change(lower_dentry, &lower_ia, NULL);
 852		inode_unlock(d_inode(lower_dentry));
 853	}
 854	return rc;
 855}
 856
 857static int
 858ecryptfs_permission(struct inode *inode, int mask)
 859{
 860	return inode_permission(ecryptfs_inode_to_lower(inode), mask);
 861}
 862
 863/**
 864 * ecryptfs_setattr
 865 * @dentry: dentry handle to the inode to modify
 866 * @ia: Structure with flags of what to change and values
 867 *
 868 * Updates the metadata of an inode. If the update is to the size
 869 * i.e. truncation, then ecryptfs_truncate will handle the size modification
 870 * of both the ecryptfs inode and the lower inode.
 871 *
 872 * All other metadata changes will be passed right to the lower filesystem,
 873 * and we will just update our inode to look like the lower.
 874 */
 875static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
 876{
 877	int rc = 0;
 878	struct dentry *lower_dentry;
 879	struct iattr lower_ia;
 880	struct inode *inode;
 881	struct inode *lower_inode;
 882	struct ecryptfs_crypt_stat *crypt_stat;
 883
 884	crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
 885	if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
 886		rc = ecryptfs_init_crypt_stat(crypt_stat);
 887		if (rc)
 888			return rc;
 889	}
 890	inode = d_inode(dentry);
 891	lower_inode = ecryptfs_inode_to_lower(inode);
 892	lower_dentry = ecryptfs_dentry_to_lower(dentry);
 893	mutex_lock(&crypt_stat->cs_mutex);
 894	if (d_is_dir(dentry))
 895		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 896	else if (d_is_reg(dentry)
 897		 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 898		     || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 899		struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 900
 901		mount_crypt_stat = &ecryptfs_superblock_to_private(
 902			dentry->d_sb)->mount_crypt_stat;
 903		rc = ecryptfs_get_lower_file(dentry, inode);
 904		if (rc) {
 905			mutex_unlock(&crypt_stat->cs_mutex);
 906			goto out;
 907		}
 908		rc = ecryptfs_read_metadata(dentry);
 909		ecryptfs_put_lower_file(inode);
 910		if (rc) {
 911			if (!(mount_crypt_stat->flags
 912			      & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 913				rc = -EIO;
 914				printk(KERN_WARNING "Either the lower file "
 915				       "is not in a valid eCryptfs format, "
 916				       "or the key could not be retrieved. "
 917				       "Plaintext passthrough mode is not "
 918				       "enabled; returning -EIO\n");
 919				mutex_unlock(&crypt_stat->cs_mutex);
 920				goto out;
 921			}
 922			rc = 0;
 923			crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 924					       | ECRYPTFS_ENCRYPTED);
 925		}
 926	}
 927	mutex_unlock(&crypt_stat->cs_mutex);
 928
 929	rc = setattr_prepare(dentry, ia);
 930	if (rc)
 931		goto out;
 932	if (ia->ia_valid & ATTR_SIZE) {
 933		rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
 934		if (rc)
 935			goto out;
 936	}
 937
 938	memcpy(&lower_ia, ia, sizeof(lower_ia));
 939	if (ia->ia_valid & ATTR_FILE)
 940		lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
 941	if (ia->ia_valid & ATTR_SIZE) {
 942		rc = truncate_upper(dentry, ia, &lower_ia);
 943		if (rc < 0)
 944			goto out;
 945	}
 946
 947	/*
 948	 * mode change is for clearing setuid/setgid bits. Allow lower fs
 949	 * to interpret this in its own way.
 950	 */
 951	if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
 952		lower_ia.ia_valid &= ~ATTR_MODE;
 953
 954	inode_lock(d_inode(lower_dentry));
 955	rc = notify_change(lower_dentry, &lower_ia, NULL);
 956	inode_unlock(d_inode(lower_dentry));
 957out:
 958	fsstack_copy_attr_all(inode, lower_inode);
 959	return rc;
 960}
 961
 962static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
 963				 struct kstat *stat)
 964{
 965	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 966	int rc = 0;
 967
 968	mount_crypt_stat = &ecryptfs_superblock_to_private(
 969						dentry->d_sb)->mount_crypt_stat;
 970	generic_fillattr(d_inode(dentry), stat);
 971	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 972		char *target;
 973		size_t targetsiz;
 974
 975		target = ecryptfs_readlink_lower(dentry, &targetsiz);
 976		if (!IS_ERR(target)) {
 977			kfree(target);
 978			stat->size = targetsiz;
 979		} else {
 980			rc = PTR_ERR(target);
 981		}
 982	}
 983	return rc;
 984}
 985
 986static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 987			    struct kstat *stat)
 988{
 989	struct kstat lower_stat;
 990	int rc;
 991
 992	rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
 993	if (!rc) {
 994		fsstack_copy_attr_all(d_inode(dentry),
 995				      ecryptfs_inode_to_lower(d_inode(dentry)));
 996		generic_fillattr(d_inode(dentry), stat);
 997		stat->blocks = lower_stat.blocks;
 998	}
 999	return rc;
1000}
1001
1002int
1003ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1004		  const char *name, const void *value,
1005		  size_t size, int flags)
1006{
1007	int rc;
1008	struct dentry *lower_dentry;
1009
1010	lower_dentry = ecryptfs_dentry_to_lower(dentry);
1011	if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1012		rc = -EOPNOTSUPP;
1013		goto out;
1014	}
 
1015	rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1016	if (!rc && inode)
1017		fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1018out:
1019	return rc;
1020}
1021
1022ssize_t
1023ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1024			const char *name, void *value, size_t size)
1025{
1026	int rc;
1027
1028	if (!(lower_inode->i_opflags & IOP_XATTR)) {
1029		rc = -EOPNOTSUPP;
1030		goto out;
1031	}
1032	inode_lock(lower_inode);
1033	rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1034	inode_unlock(lower_inode);
 
1035out:
1036	return rc;
1037}
1038
1039static ssize_t
1040ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1041		  const char *name, void *value, size_t size)
1042{
1043	return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1044				       ecryptfs_inode_to_lower(inode),
1045				       name, value, size);
1046}
1047
1048static ssize_t
1049ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1050{
1051	int rc = 0;
1052	struct dentry *lower_dentry;
1053
1054	lower_dentry = ecryptfs_dentry_to_lower(dentry);
1055	if (!d_inode(lower_dentry)->i_op->listxattr) {
1056		rc = -EOPNOTSUPP;
1057		goto out;
1058	}
1059	inode_lock(d_inode(lower_dentry));
1060	rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1061	inode_unlock(d_inode(lower_dentry));
1062out:
1063	return rc;
1064}
1065
1066static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1067				const char *name)
1068{
1069	int rc;
1070	struct dentry *lower_dentry;
1071	struct inode *lower_inode;
1072
1073	lower_dentry = ecryptfs_dentry_to_lower(dentry);
1074	lower_inode = ecryptfs_inode_to_lower(inode);
1075	if (!(lower_inode->i_opflags & IOP_XATTR)) {
1076		rc = -EOPNOTSUPP;
1077		goto out;
1078	}
1079	inode_lock(lower_inode);
1080	rc = __vfs_removexattr(lower_dentry, name);
1081	inode_unlock(lower_inode);
1082out:
1083	return rc;
1084}
1085
1086const struct inode_operations ecryptfs_symlink_iops = {
 
1087	.get_link = ecryptfs_get_link,
1088	.permission = ecryptfs_permission,
1089	.setattr = ecryptfs_setattr,
1090	.getattr = ecryptfs_getattr_link,
 
 
1091	.listxattr = ecryptfs_listxattr,
 
1092};
1093
1094const struct inode_operations ecryptfs_dir_iops = {
1095	.create = ecryptfs_create,
1096	.lookup = ecryptfs_lookup,
1097	.link = ecryptfs_link,
1098	.unlink = ecryptfs_unlink,
1099	.symlink = ecryptfs_symlink,
1100	.mkdir = ecryptfs_mkdir,
1101	.rmdir = ecryptfs_rmdir,
1102	.mknod = ecryptfs_mknod,
1103	.rename = ecryptfs_rename,
1104	.permission = ecryptfs_permission,
1105	.setattr = ecryptfs_setattr,
 
 
1106	.listxattr = ecryptfs_listxattr,
 
1107};
1108
1109const struct inode_operations ecryptfs_main_iops = {
1110	.permission = ecryptfs_permission,
1111	.setattr = ecryptfs_setattr,
1112	.getattr = ecryptfs_getattr,
 
 
1113	.listxattr = ecryptfs_listxattr,
1114};
1115
1116static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1117			      struct dentry *dentry, struct inode *inode,
1118			      const char *name, void *buffer, size_t size)
1119{
1120	return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1121}
1122
1123static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1124			      struct dentry *dentry, struct inode *inode,
1125			      const char *name, const void *value, size_t size,
1126			      int flags)
1127{
1128	if (value)
1129		return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1130	else {
1131		BUG_ON(flags != XATTR_REPLACE);
1132		return ecryptfs_removexattr(dentry, inode, name);
1133	}
1134}
1135
1136const struct xattr_handler ecryptfs_xattr_handler = {
1137	.prefix = "",  /* match anything */
1138	.get = ecryptfs_xattr_get,
1139	.set = ecryptfs_xattr_set,
1140};
1141
1142const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1143	&ecryptfs_xattr_handler,
1144	NULL
1145};