inode.c 29.8 KB
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/**
 * eCryptfs: Linux filesystem encryption layer
 *
 * Copyright (C) 1997-2004 Erez Zadok
 * Copyright (C) 2001-2004 Stony Brook University
 * Copyright (C) 2004-2006 International Business Machines Corp.
 *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
 *              Michael C. Thompsion <mcthomps@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <linux/file.h>
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/crypto.h>
#include "ecryptfs_kernel.h"

static struct dentry *lock_parent(struct dentry *dentry)
{
	struct dentry *dir;

	dir = dget(dentry->d_parent);
	mutex_lock(&(dir->d_inode->i_mutex));
	return dir;
}

static void unlock_parent(struct dentry *dentry)
{
	mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
	dput(dentry->d_parent);
}

static void unlock_dir(struct dentry *dir)
{
	mutex_unlock(&dir->d_inode->i_mutex);
	dput(dir);
}

void ecryptfs_copy_inode_size(struct inode *dst, const struct inode *src)
{
	i_size_write(dst, i_size_read((struct inode *)src));
	dst->i_blocks = src->i_blocks;
}

void ecryptfs_copy_attr_atime(struct inode *dest, const struct inode *src)
{
	dest->i_atime = src->i_atime;
}

static void ecryptfs_copy_attr_times(struct inode *dest,
				     const struct inode *src)
{
	dest->i_atime = src->i_atime;
	dest->i_mtime = src->i_mtime;
	dest->i_ctime = src->i_ctime;
}

static void ecryptfs_copy_attr_timesizes(struct inode *dest,
					 const struct inode *src)
{
	dest->i_atime = src->i_atime;
	dest->i_mtime = src->i_mtime;
	dest->i_ctime = src->i_ctime;
	ecryptfs_copy_inode_size(dest, src);
}

void ecryptfs_copy_attr_all(struct inode *dest, const struct inode *src)
{
	dest->i_mode = src->i_mode;
	dest->i_nlink = src->i_nlink;
	dest->i_uid = src->i_uid;
	dest->i_gid = src->i_gid;
	dest->i_rdev = src->i_rdev;
	dest->i_atime = src->i_atime;
	dest->i_mtime = src->i_mtime;
	dest->i_ctime = src->i_ctime;
	dest->i_blkbits = src->i_blkbits;
	dest->i_flags = src->i_flags;
}

/**
 * ecryptfs_create_underlying_file
 * @lower_dir_inode: inode of the parent in the lower fs of the new file
 * @lower_dentry: New file's dentry in the lower fs
 * @ecryptfs_dentry: New file's dentry in ecryptfs
 * @mode: The mode of the new file
 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 *
 * Creates the file in the lower file system.
 *
 * Returns zero on success; non-zero on error condition
 */
static int
ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
				struct dentry *dentry, int mode,
				struct nameidata *nd)
{
	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
	struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
	struct dentry *dentry_save;
	struct vfsmount *vfsmount_save;
	int rc;

	dentry_save = nd->dentry;
	vfsmount_save = nd->mnt;
	nd->dentry = lower_dentry;
	nd->mnt = lower_mnt;
	rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
	nd->dentry = dentry_save;
	nd->mnt = vfsmount_save;
	return rc;
}

/**
 * ecryptfs_do_create
 * @directory_inode: inode of the new file's dentry's parent in ecryptfs
 * @ecryptfs_dentry: New file's dentry in ecryptfs
 * @mode: The mode of the new file
 * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
 *
 * Creates the underlying file and the eCryptfs inode which will link to
 * it. It will also update the eCryptfs directory inode to mimic the
 * stat of the lower directory inode.
 *
 * Returns zero on success; non-zero on error condition
 */
static int
ecryptfs_do_create(struct inode *directory_inode,
		   struct dentry *ecryptfs_dentry, int mode,
		   struct nameidata *nd)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	if (unlikely(IS_ERR(lower_dir_dentry))) {
		ecryptfs_printk(KERN_ERR, "Error locking directory of "
				"dentry\n");
		rc = PTR_ERR(lower_dir_dentry);
		goto out;
	}
	rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
					     ecryptfs_dentry, mode, nd);
	if (unlikely(rc)) {
		ecryptfs_printk(KERN_ERR,
				"Failure to create underlying file\n");
		goto out_lock;
	}
	rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
				directory_inode->i_sb, 0);
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
		goto out_lock;
	}
	ecryptfs_copy_attr_timesizes(directory_inode,
				     lower_dir_dentry->d_inode);
out_lock:
	unlock_dir(lower_dir_dentry);
out:
	return rc;
}

/**
 * grow_file
 * @ecryptfs_dentry: the ecryptfs dentry
 * @lower_file: The lower file
 * @inode: The ecryptfs inode
 * @lower_inode: The lower inode
 *
 * This is the code which will grow the file to its correct size.
 */
static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
		     struct inode *inode, struct inode *lower_inode)
{
	int rc = 0;
	struct file fake_file;
	struct ecryptfs_file_info tmp_file_info;

	memset(&fake_file, 0, sizeof(fake_file));
	fake_file.f_dentry = ecryptfs_dentry;
	memset(&tmp_file_info, 0, sizeof(tmp_file_info));
	ecryptfs_set_file_private(&fake_file, &tmp_file_info);
	ecryptfs_set_file_lower(&fake_file, lower_file);
	rc = ecryptfs_fill_zeros(&fake_file, 1);
	if (rc) {
		ECRYPTFS_SET_FLAG(
			ecryptfs_inode_to_private(inode)->crypt_stat.flags,
			ECRYPTFS_SECURITY_WARNING);
		ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
				"in file; rc = [%d]\n", rc);
		goto out;
	}
	i_size_write(inode, 0);
	ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
	ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
			  ECRYPTFS_NEW_FILE);
out:
	return rc;
}

/**
 * ecryptfs_initialize_file
 *
 * Cause the file to be changed from a basic empty file to an ecryptfs
 * file with a header and first data page.
 *
 * Returns zero on success
 */
static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
{
	int rc = 0;
	int lower_flags;
	struct ecryptfs_crypt_stat *crypt_stat;
	struct dentry *lower_dentry;
	struct file *lower_file;
	struct inode *inode, *lower_inode;
	struct vfsmount *lower_mnt;

	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
	ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
			lower_dentry->d_name.name);
	inode = ecryptfs_dentry->d_inode;
	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
	lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
#if BITS_PER_LONG != 32
	lower_flags |= O_LARGEFILE;
#endif
	lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
	/* Corresponding fput() at end of this function */
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	if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
					   lower_flags))) {
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		ecryptfs_printk(KERN_ERR,
				"Error opening dentry; rc = [%i]\n", rc);
		goto out;
	}
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	lower_inode = lower_dentry->d_inode;
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	if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
		ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
		ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
		goto out_fput;
	}
	ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
	ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
	rc = ecryptfs_new_file_context(ecryptfs_dentry);
	if (rc) {
		ecryptfs_printk(KERN_DEBUG, "Error creating new file "
				"context\n");
		goto out_fput;
	}
	rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
	if (rc) {
		ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
		goto out_fput;
	}
	rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
out_fput:
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	if ((rc = ecryptfs_close_lower_file(lower_file)))
		printk(KERN_ERR "Error closing lower_file\n");
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out:
	return rc;
}

/**
 * ecryptfs_create
 * @dir: The inode of the directory in which to create the file.
 * @dentry: The eCryptfs dentry
 * @mode: The mode of the new file.
 * @nd: nameidata
 *
 * Creates a new file.
 *
 * Returns zero on success; non-zero on error condition
 */
static int
ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
		int mode, struct nameidata *nd)
{
	int rc;

	rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
	if (unlikely(rc)) {
		ecryptfs_printk(KERN_WARNING, "Failed to create file in"
				"lower filesystem\n");
		goto out;
	}
	/* At this point, a file exists on "disk"; we need to make sure
	 * that this on disk file is prepared to be an ecryptfs file */
	rc = ecryptfs_initialize_file(ecryptfs_dentry);
out:
	return rc;
}

/**
 * ecryptfs_lookup
 * @dir: inode
 * @dentry: The dentry
 * @nd: nameidata, may be NULL
 *
 * Find a file on disk. If the file does not exist, then we'll add it to the
 * dentry cache and continue on to read it from the disk.
 */
static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
				      struct nameidata *nd)
{
	int rc = 0;
	struct dentry *lower_dir_dentry;
	struct dentry *lower_dentry;
	struct vfsmount *lower_mnt;
	char *encoded_name;
	unsigned int encoded_namelen;
	struct ecryptfs_crypt_stat *crypt_stat = NULL;
	char *page_virt = NULL;
	struct inode *lower_inode;
	u64 file_size;

	lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
	dentry->d_op = &ecryptfs_dops;
	if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
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	    || (dentry->d_name.len == 2
		&& !strcmp(dentry->d_name.name, ".."))) {
		d_drop(dentry);
		goto out;
	}
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	encoded_namelen = ecryptfs_encode_filename(crypt_stat,
						   dentry->d_name.name,
						   dentry->d_name.len,
						   &encoded_name);
	if (encoded_namelen < 0) {
		rc = encoded_namelen;
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		d_drop(dentry);
		goto out;
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	}
	ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
			"= [%d]\n", encoded_name, encoded_namelen);
	lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
				      encoded_namelen - 1);
	kfree(encoded_name);
	if (IS_ERR(lower_dentry)) {
		ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
		rc = PTR_ERR(lower_dentry);
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		d_drop(dentry);
		goto out;
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	}
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	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
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	ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
       		"d_name.name = [%s]\n", lower_dentry,
		lower_dentry->d_name.name);
	lower_inode = lower_dentry->d_inode;
	ecryptfs_copy_attr_atime(dir, lower_dir_dentry->d_inode);
	BUG_ON(!atomic_read(&lower_dentry->d_count));
	ecryptfs_set_dentry_private(dentry,
				    kmem_cache_alloc(ecryptfs_dentry_info_cache,
						     SLAB_KERNEL));
	if (!ecryptfs_dentry_to_private(dentry)) {
		rc = -ENOMEM;
		ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
				"to allocate ecryptfs_dentry_info struct\n");
		goto out_dput;
	}
	ecryptfs_set_dentry_lower(dentry, lower_dentry);
	ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
	if (!lower_dentry->d_inode) {
		/* We want to add because we couldn't find in lower */
		d_add(dentry, NULL);
		goto out;
	}
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Error interposing\n");
		goto out_dput;
	}
	if (S_ISDIR(lower_inode->i_mode)) {
		ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
		goto out;
	}
	if (S_ISLNK(lower_inode->i_mode)) {
		ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
		goto out;
	}
	if (!nd) {
		ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
				"as we *think* we are about to unlink\n");
		goto out;
	}
	/* Released in this function */
	page_virt =
	    (char *)kmem_cache_alloc(ecryptfs_header_cache_2,
				     SLAB_USER);
	if (!page_virt) {
		rc = -ENOMEM;
		ecryptfs_printk(KERN_ERR,
				"Cannot ecryptfs_kmalloc a page\n");
		goto out_dput;
	}
	memset(page_virt, 0, PAGE_CACHE_SIZE);
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	rc = ecryptfs_read_header_region(page_virt, lower_dentry, nd->mnt);
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	crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
	if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
		ecryptfs_set_default_sizes(crypt_stat);
	if (rc) {
		rc = 0;
		ecryptfs_printk(KERN_WARNING, "Error reading header region;"
				" assuming unencrypted\n");
	} else {
		if (!contains_ecryptfs_marker(page_virt
					      + ECRYPTFS_FILE_SIZE_BYTES)) {
			kmem_cache_free(ecryptfs_header_cache_2, page_virt);
			goto out;
		}
		memcpy(&file_size, page_virt, sizeof(file_size));
		file_size = be64_to_cpu(file_size);
		i_size_write(dentry->d_inode, (loff_t)file_size);
	}
	kmem_cache_free(ecryptfs_header_cache_2, page_virt);
	goto out;

out_dput:
	dput(lower_dentry);
	d_drop(dentry);
out:
	return ERR_PTR(rc);
}

static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
			 struct dentry *new_dentry)
{
	struct dentry *lower_old_dentry;
	struct dentry *lower_new_dentry;
	struct dentry *lower_dir_dentry;
	u64 file_size_save;
	int rc;

	file_size_save = i_size_read(old_dentry->d_inode);
	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
	dget(lower_old_dentry);
	dget(lower_new_dentry);
	lower_dir_dentry = lock_parent(lower_new_dentry);
	rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
		      lower_new_dentry);
	if (rc || !lower_new_dentry->d_inode)
		goto out_lock;
	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
	if (rc)
		goto out_lock;
	ecryptfs_copy_attr_timesizes(dir, lower_new_dentry->d_inode);
	old_dentry->d_inode->i_nlink =
		ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
	i_size_write(new_dentry->d_inode, file_size_save);
out_lock:
	unlock_dir(lower_dir_dentry);
	dput(lower_new_dentry);
	dput(lower_old_dentry);
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	d_drop(new_dentry);
	d_drop(old_dentry);
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	return rc;
}

static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
{
	int rc = 0;
	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
	struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);

	lock_parent(lower_dentry);
	rc = vfs_unlink(lower_dir_inode, lower_dentry);
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Error in vfs_unlink\n");
		goto out_unlock;
	}
	ecryptfs_copy_attr_times(dir, lower_dir_inode);
	dentry->d_inode->i_nlink =
		ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
	dentry->d_inode->i_ctime = dir->i_ctime;
out_unlock:
	unlock_parent(lower_dentry);
	return rc;
}

static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
			    const char *symname)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;
	umode_t mode;
	char *encoded_symname;
	unsigned int encoded_symlen;
	struct ecryptfs_crypt_stat *crypt_stat = NULL;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	dget(lower_dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	mode = S_IALLUGO;
	encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
						  strlen(symname),
						  &encoded_symname);
	if (encoded_symlen < 0) {
		rc = encoded_symlen;
		goto out_lock;
	}
	rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
			 encoded_symname, mode);
	kfree(encoded_symname);
	if (rc || !lower_dentry->d_inode)
		goto out_lock;
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
	if (rc)
		goto out_lock;
	ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
out_lock:
	unlock_dir(lower_dir_dentry);
	dput(lower_dentry);
	if (!dentry->d_inode)
		d_drop(dentry);
	return rc;
}

static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
	if (rc || !lower_dentry->d_inode)
		goto out;
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
	if (rc)
		goto out;
	ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
out:
	unlock_dir(lower_dir_dentry);
	if (!dentry->d_inode)
		d_drop(dentry);
	return rc;
}

static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
{
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;
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	int rc;
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	lower_dentry = ecryptfs_dentry_to_lower(dentry);
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	dget(dentry);
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	lower_dir_dentry = lock_parent(lower_dentry);
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	dget(lower_dentry);
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	rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
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	dput(lower_dentry);
	if (!rc)
		d_delete(lower_dentry);
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	ecryptfs_copy_attr_times(dir, lower_dir_dentry->d_inode);
	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
	unlock_dir(lower_dir_dentry);
	if (!rc)
		d_drop(dentry);
580
	dput(dentry);
581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802
	return rc;
}

static int
ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
	if (rc || !lower_dentry->d_inode)
		goto out;
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
	if (rc)
		goto out;
	ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
out:
	unlock_dir(lower_dir_dentry);
	if (!dentry->d_inode)
		d_drop(dentry);
	return rc;
}

static int
ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
		struct inode *new_dir, struct dentry *new_dentry)
{
	int rc;
	struct dentry *lower_old_dentry;
	struct dentry *lower_new_dentry;
	struct dentry *lower_old_dir_dentry;
	struct dentry *lower_new_dir_dentry;

	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
	dget(lower_old_dentry);
	dget(lower_new_dentry);
	lower_old_dir_dentry = dget_parent(lower_old_dentry);
	lower_new_dir_dentry = dget_parent(lower_new_dentry);
	lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
	rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
			lower_new_dir_dentry->d_inode, lower_new_dentry);
	if (rc)
		goto out_lock;
	ecryptfs_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
	if (new_dir != old_dir)
		ecryptfs_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
out_lock:
	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
	dput(lower_new_dentry);
	dput(lower_old_dentry);
	return rc;
}

static int
ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
{
	int rc;
	struct dentry *lower_dentry;
	char *decoded_name;
	char *lower_buf;
	mm_segment_t old_fs;
	struct ecryptfs_crypt_stat *crypt_stat;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op ||
	    !lower_dentry->d_inode->i_op->readlink) {
		rc = -EINVAL;
		goto out;
	}
	/* Released in this function */
	lower_buf = kmalloc(bufsiz, GFP_KERNEL);
	if (lower_buf == NULL) {
		ecryptfs_printk(KERN_ERR, "Out of memory\n");
		rc = -ENOMEM;
		goto out;
	}
	old_fs = get_fs();
	set_fs(get_ds());
	ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
			"lower_dentry->d_name.name = [%s]\n",
			lower_dentry->d_name.name);
	rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
						   (char __user *)lower_buf,
						   bufsiz);
	set_fs(old_fs);
	if (rc >= 0) {
		crypt_stat = NULL;
		rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
					      &decoded_name);
		if (rc == -ENOMEM)
			goto out_free_lower_buf;
		if (rc > 0) {
			ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
					"to userspace: [%*s]\n", rc,
					decoded_name);
			if (copy_to_user(buf, decoded_name, rc))
				rc = -EFAULT;
		}
		kfree(decoded_name);
		ecryptfs_copy_attr_atime(dentry->d_inode,
					 lower_dentry->d_inode);
	}
out_free_lower_buf:
	kfree(lower_buf);
out:
	return rc;
}

static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	char *buf;
	int len = PAGE_SIZE, rc;
	mm_segment_t old_fs;

	/* Released in ecryptfs_put_link(); only release here on error */
	buf = kmalloc(len, GFP_KERNEL);
	if (!buf) {
		rc = -ENOMEM;
		goto out;
	}
	old_fs = get_fs();
	set_fs(get_ds());
	ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
			"dentry->d_name.name = [%s]\n", dentry->d_name.name);
	rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
	buf[rc] = '\0';
	set_fs(old_fs);
	if (rc < 0)
		goto out_free;
	rc = 0;
	nd_set_link(nd, buf);
	goto out;
out_free:
	kfree(buf);
out:
	return ERR_PTR(rc);
}

static void
ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
{
	/* Free the char* */
	kfree(nd_get_link(nd));
}

/**
 * upper_size_to_lower_size
 * @crypt_stat: Crypt_stat associated with file
 * @upper_size: Size of the upper file
 *
 * Calculate the requried size of the lower file based on the
 * specified size of the upper file. This calculation is based on the
 * number of headers in the underlying file and the extent size.
 *
 * Returns Calculated size of the lower file.
 */
static loff_t
upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
			 loff_t upper_size)
{
	loff_t lower_size;

	lower_size = ( crypt_stat->header_extent_size
		       * crypt_stat->num_header_extents_at_front );
	if (upper_size != 0) {
		loff_t num_extents;

		num_extents = upper_size >> crypt_stat->extent_shift;
		if (upper_size & ~crypt_stat->extent_mask)
			num_extents++;
		lower_size += (num_extents * crypt_stat->extent_size);
	}
	return lower_size;
}

/**
 * ecryptfs_truncate
 * @dentry: The ecryptfs layer dentry
 * @new_length: The length to expand the file to
 *
 * Function to handle truncations modifying the size of the file. Note
 * that the file sizes are interpolated. When expanding, we are simply
 * writing strings of 0's out. When truncating, we need to modify the
 * underlying file size according to the page index interpolations.
 *
 * Returns zero on success; non-zero otherwise
 */
int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
{
	int rc = 0;
	struct inode *inode = dentry->d_inode;
	struct dentry *lower_dentry;
	struct vfsmount *lower_mnt;
	struct file fake_ecryptfs_file, *lower_file = NULL;
	struct ecryptfs_crypt_stat *crypt_stat;
	loff_t i_size = i_size_read(inode);
	loff_t lower_size_before_truncate;
	loff_t lower_size_after_truncate;

	if (unlikely((new_length == i_size)))
		goto out;
	crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
	/* Set up a fake ecryptfs file, this is used to interface with
	 * the file in the underlying filesystem so that the
	 * truncation has an effect there as well. */
	memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
	fake_ecryptfs_file.f_dentry = dentry;
	/* Released at out_free: label */
	ecryptfs_set_file_private(&fake_ecryptfs_file,
				  kmem_cache_alloc(ecryptfs_file_info_cache,
						   SLAB_KERNEL));
	if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
		rc = -ENOMEM;
		goto out;
	}
	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	/* This dget & mntget is released through fput at out_fput: */
	lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
803 804 805 806
	if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
					   O_RDWR))) {
		ecryptfs_printk(KERN_ERR,
				"Error opening dentry; rc = [%i]\n", rc);
807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847
		goto out_free;
	}
	ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
	/* Switch on growing or shrinking file */
	if (new_length > i_size) {
		rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
		if (rc) {
			ecryptfs_printk(KERN_ERR,
					"Problem with fill_zeros\n");
			goto out_fput;
		}
		i_size_write(inode, new_length);
		rc = ecryptfs_write_inode_size_to_header(lower_file,
							 lower_dentry->d_inode,
							 inode);
		if (rc) {
			ecryptfs_printk(KERN_ERR,
					"Problem with ecryptfs_write"
					"_inode_size\n");
			goto out_fput;
		}
	} else { /* new_length < i_size_read(inode) */
		vmtruncate(inode, new_length);
		ecryptfs_write_inode_size_to_header(lower_file,
						    lower_dentry->d_inode,
						    inode);
		/* We are reducing the size of the ecryptfs file, and need to
		 * know if we need to reduce the size of the lower file. */
		lower_size_before_truncate =
		    upper_size_to_lower_size(crypt_stat, i_size);
		lower_size_after_truncate =
		    upper_size_to_lower_size(crypt_stat, new_length);
		if (lower_size_after_truncate < lower_size_before_truncate)
			vmtruncate(lower_dentry->d_inode,
				   lower_size_after_truncate);
	}
	/* Update the access times */
	lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
		= CURRENT_TIME;
	mark_inode_dirty_sync(inode);
out_fput:
848 849
	if ((rc = ecryptfs_close_lower_file(lower_file)))
		printk(KERN_ERR "Error closing lower_file\n");
850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046
out_free:
	if (ecryptfs_file_to_private(&fake_ecryptfs_file))
		kmem_cache_free(ecryptfs_file_info_cache,
				ecryptfs_file_to_private(&fake_ecryptfs_file));
out:
	return rc;
}

static int
ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
{
	int rc;

        if (nd) {
		struct vfsmount *vfsmnt_save = nd->mnt;
		struct dentry *dentry_save = nd->dentry;

		nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
		nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
		rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
		nd->mnt = vfsmnt_save;
		nd->dentry = dentry_save;
        } else
		rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
        return rc;
}

/**
 * ecryptfs_setattr
 * @dentry: dentry handle to the inode to modify
 * @ia: Structure with flags of what to change and values
 *
 * Updates the metadata of an inode. If the update is to the size
 * i.e. truncation, then ecryptfs_truncate will handle the size modification
 * of both the ecryptfs inode and the lower inode.
 *
 * All other metadata changes will be passed right to the lower filesystem,
 * and we will just update our inode to look like the lower.
 */
static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
{
	int rc = 0;
	struct dentry *lower_dentry;
	struct inode *inode;
	struct inode *lower_inode;
	struct ecryptfs_crypt_stat *crypt_stat;

	crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	inode = dentry->d_inode;
	lower_inode = ecryptfs_inode_to_lower(inode);
	if (ia->ia_valid & ATTR_SIZE) {
		ecryptfs_printk(KERN_DEBUG,
				"ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
				ia->ia_valid, ATTR_SIZE);
		rc = ecryptfs_truncate(dentry, ia->ia_size);
		/* ecryptfs_truncate handles resizing of the lower file */
		ia->ia_valid &= ~ATTR_SIZE;
		ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
				ia->ia_valid);
		if (rc < 0)
			goto out;
	}
	rc = notify_change(lower_dentry, ia);
out:
	ecryptfs_copy_attr_all(inode, lower_inode);
	return rc;
}

static int
ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
		  size_t size, int flags)
{
	int rc = 0;
	struct dentry *lower_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op->setxattr) {
		rc = -ENOSYS;
		goto out;
	}
	mutex_lock(&lower_dentry->d_inode->i_mutex);
	rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
						   size, flags);
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
out:
	return rc;
}

static ssize_t
ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
		  size_t size)
{
	int rc = 0;
	struct dentry *lower_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op->getxattr) {
		rc = -ENOSYS;
		goto out;
	}
	mutex_lock(&lower_dentry->d_inode->i_mutex);
	rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
						   size);
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
out:
	return rc;
}

static ssize_t
ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
{
	int rc = 0;
	struct dentry *lower_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op->listxattr) {
		rc = -ENOSYS;
		goto out;
	}
	mutex_lock(&lower_dentry->d_inode->i_mutex);
	rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
out:
	return rc;
}

static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
{
	int rc = 0;
	struct dentry *lower_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op->removexattr) {
		rc = -ENOSYS;
		goto out;
	}
	mutex_lock(&lower_dentry->d_inode->i_mutex);
	rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
out:
	return rc;
}

int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
{
	if ((ecryptfs_inode_to_lower(inode)
	     == (struct inode *)candidate_lower_inode))
		return 1;
	else
		return 0;
}

int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
{
	ecryptfs_init_inode(inode, (struct inode *)lower_inode);
	return 0;
}

struct inode_operations ecryptfs_symlink_iops = {
	.readlink = ecryptfs_readlink,
	.follow_link = ecryptfs_follow_link,
	.put_link = ecryptfs_put_link,
	.permission = ecryptfs_permission,
	.setattr = ecryptfs_setattr,
	.setxattr = ecryptfs_setxattr,
	.getxattr = ecryptfs_getxattr,
	.listxattr = ecryptfs_listxattr,
	.removexattr = ecryptfs_removexattr
};

struct inode_operations ecryptfs_dir_iops = {
	.create = ecryptfs_create,
	.lookup = ecryptfs_lookup,
	.link = ecryptfs_link,
	.unlink = ecryptfs_unlink,
	.symlink = ecryptfs_symlink,
	.mkdir = ecryptfs_mkdir,
	.rmdir = ecryptfs_rmdir,
	.mknod = ecryptfs_mknod,
	.rename = ecryptfs_rename,
	.permission = ecryptfs_permission,
	.setattr = ecryptfs_setattr,
	.setxattr = ecryptfs_setxattr,
	.getxattr = ecryptfs_getxattr,
	.listxattr = ecryptfs_listxattr,
	.removexattr = ecryptfs_removexattr
};

struct inode_operations ecryptfs_main_iops = {
	.permission = ecryptfs_permission,
	.setattr = ecryptfs_setattr,
	.setxattr = ecryptfs_setxattr,
	.getxattr = ecryptfs_getxattr,
	.listxattr = ecryptfs_listxattr,
	.removexattr = ecryptfs_removexattr
};