inode.c 32.5 KB
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/**
 * eCryptfs: Linux filesystem encryption layer
 *
 * Copyright (C) 1997-2004 Erez Zadok
 * Copyright (C) 2001-2004 Stony Brook University
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 * Copyright (C) 2004-2007 International Business Machines Corp.
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 *   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>
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#include <linux/fs_stack.h>
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#include <asm/unaligned.h>
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#include "ecryptfs_kernel.h"

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

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	dir = dget_parent(dentry);
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	mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
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	return dir;
}

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

/**
 * ecryptfs_create_underlying_file
 * @lower_dir_inode: inode of the parent in the lower fs of the new file
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 * @dentry: New file's dentry
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 * @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;

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	dentry_save = nd->path.dentry;
	vfsmount_save = nd->path.mnt;
	nd->path.dentry = lower_dentry;
	nd->path.mnt = lower_mnt;
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	rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
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	nd->path.dentry = dentry_save;
	nd->path.mnt = vfsmount_save;
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	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);
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	if (IS_ERR(lower_dir_dentry)) {
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		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);
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	if (rc) {
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		printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
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		       "rc = [%d]\n", __func__, rc);
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		goto out_lock;
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	}
	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;
	}
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	fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
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out_lock:
	unlock_dir(lower_dir_dentry);
out:
	return rc;
}

/**
 * grow_file
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 * @ecryptfs_dentry: the eCryptfs dentry
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 *
 * This is the code which will grow the file to its correct size.
 */
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static int grow_file(struct dentry *ecryptfs_dentry)
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{
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	struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
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	struct file fake_file;
	struct ecryptfs_file_info tmp_file_info;
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	char zero_virt[] = { 0x00 };
	int rc = 0;
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	memset(&fake_file, 0, sizeof(fake_file));
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	fake_file.f_path.dentry = ecryptfs_dentry;
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	memset(&tmp_file_info, 0, sizeof(tmp_file_info));
	ecryptfs_set_file_private(&fake_file, &tmp_file_info);
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	ecryptfs_set_file_lower(
		&fake_file,
		ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
	rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
	i_size_write(ecryptfs_inode, 0);
	rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
	ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
		ECRYPTFS_NEW_FILE;
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	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)
{
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	struct ecryptfs_crypt_stat *crypt_stat =
		&ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
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	int rc = 0;

	if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
		ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
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		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
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		goto out;
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	}
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	crypt_stat->flags |= ECRYPTFS_NEW_FILE;
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	ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
	rc = ecryptfs_new_file_context(ecryptfs_dentry);
	if (rc) {
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		ecryptfs_printk(KERN_ERR, "Error creating new file "
				"context; rc = [%d]\n", rc);
		goto out;
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	}
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	if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
		rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
		if (rc) {
			printk(KERN_ERR "%s: Error attempting to initialize "
			       "the persistent file for the dentry with name "
			       "[%s]; rc = [%d]\n", __func__,
			       ecryptfs_dentry->d_name.name, rc);
			goto out;
		}
	}
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	rc = ecryptfs_write_metadata(ecryptfs_dentry);
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	if (rc) {
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		printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
		goto out;
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	}
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	rc = grow_file(ecryptfs_dentry);
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	if (rc)
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		printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
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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;

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	/* ecryptfs_do_create() calls ecryptfs_interpose() */
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	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;
}

/**
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 * ecryptfs_lookup_and_interpose_lower - Perform a lookup
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 */
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int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
					struct dentry *lower_dentry,
					struct inode *ecryptfs_dir_inode,
					struct nameidata *ecryptfs_nd)
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{
	struct dentry *lower_dir_dentry;
	struct vfsmount *lower_mnt;
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	struct inode *lower_inode;
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	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
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	struct ecryptfs_crypt_stat *crypt_stat;
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	char *page_virt = NULL;
	u64 file_size;
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	int rc = 0;
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	lower_dir_dentry = lower_dentry->d_parent;
	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
				   ecryptfs_dentry->d_parent));
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	lower_inode = lower_dentry->d_inode;
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	fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
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	BUG_ON(!atomic_read(&lower_dentry->d_count));
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	ecryptfs_set_dentry_private(ecryptfs_dentry,
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				    kmem_cache_alloc(ecryptfs_dentry_info_cache,
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						     GFP_KERNEL));
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	if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
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		rc = -ENOMEM;
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		printk(KERN_ERR "%s: Out of memory whilst attempting "
		       "to allocate ecryptfs_dentry_info struct\n",
			__func__);
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		goto out_dput;
	}
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	ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
	ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
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	if (!lower_dentry->d_inode) {
		/* We want to add because we couldn't find in lower */
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		d_add(ecryptfs_dentry, NULL);
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		goto out;
	}
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	rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
				ecryptfs_dir_inode->i_sb, 1);
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	if (rc) {
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		printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
		       __func__, rc);
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		goto out;
290
	}
291
	if (S_ISDIR(lower_inode->i_mode))
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		goto out;
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	if (S_ISLNK(lower_inode->i_mode))
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		goto out;
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	if (special_file(lower_inode->i_mode))
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		goto out;
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	if (!ecryptfs_nd)
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		goto out;
	/* Released in this function */
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	page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
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	if (!page_virt) {
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		printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
		       __func__);
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		rc = -ENOMEM;
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		goto out;
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	}
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	if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
		rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
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		if (rc) {
			printk(KERN_ERR "%s: Error attempting to initialize "
			       "the persistent file for the dentry with name "
			       "[%s]; rc = [%d]\n", __func__,
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			       ecryptfs_dentry->d_name.name, rc);
			goto out_free_kmem;
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		}
	}
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	crypt_stat = &ecryptfs_inode_to_private(
					ecryptfs_dentry->d_inode)->crypt_stat;
	/* TODO: lock for crypt_stat comparison */
	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
			ecryptfs_set_default_sizes(crypt_stat);
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	rc = ecryptfs_read_and_validate_header_region(page_virt,
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						      ecryptfs_dentry->d_inode);
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	if (rc) {
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		rc = ecryptfs_read_and_validate_xattr_region(page_virt,
							     ecryptfs_dentry);
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		if (rc) {
			rc = 0;
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			goto out_free_kmem;
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		}
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		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
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	}
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	mount_crypt_stat = &ecryptfs_superblock_to_private(
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		ecryptfs_dentry->d_sb)->mount_crypt_stat;
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	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
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			file_size = (crypt_stat->num_header_bytes_at_front
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				     + i_size_read(lower_dentry->d_inode));
		else
			file_size = i_size_read(lower_dentry->d_inode);
	} else {
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		file_size = get_unaligned_be64(page_virt);
343
	}
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	i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
out_free_kmem:
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	kmem_cache_free(ecryptfs_header_cache_2, page_virt);
	goto out;
out_dput:
	dput(lower_dentry);
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	d_drop(ecryptfs_dentry);
out:
	return rc;
}

/**
 * ecryptfs_lookup
 * @ecryptfs_dir_inode: The eCryptfs directory inode
 * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
 * @ecryptfs_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 *ecryptfs_dir_inode,
				      struct dentry *ecryptfs_dentry,
				      struct nameidata *ecryptfs_nd)
{
	char *encrypted_and_encoded_name = NULL;
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	size_t encrypted_and_encoded_name_size;
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	struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
	struct dentry *lower_dir_dentry, *lower_dentry;
	int rc = 0;

	ecryptfs_dentry->d_op = &ecryptfs_dops;
	if ((ecryptfs_dentry->d_name.len == 1
	     && !strcmp(ecryptfs_dentry->d_name.name, "."))
	    || (ecryptfs_dentry->d_name.len == 2
		&& !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
		goto out_d_drop;
	}
	lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
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	mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
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	lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
				      lower_dir_dentry,
				      ecryptfs_dentry->d_name.len);
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	mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
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	if (IS_ERR(lower_dentry)) {
		rc = PTR_ERR(lower_dentry);
		printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
		       "lower_dentry = [%s]\n", __func__, rc,
		       ecryptfs_dentry->d_name.name);
		goto out_d_drop;
	}
	if (lower_dentry->d_inode)
		goto lookup_and_interpose;
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	mount_crypt_stat = &ecryptfs_superblock_to_private(
				ecryptfs_dentry->d_sb)->mount_crypt_stat;
	if (!(mount_crypt_stat
	    && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
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		goto lookup_and_interpose;
	dput(lower_dentry);
	rc = ecryptfs_encrypt_and_encode_filename(
		&encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
404
		NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
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		ecryptfs_dentry->d_name.len);
	if (rc) {
		printk(KERN_ERR "%s: Error attempting to encrypt and encode "
		       "filename; rc = [%d]\n", __func__, rc);
		goto out_d_drop;
	}
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	mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
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	lower_dentry = lookup_one_len(encrypted_and_encoded_name,
				      lower_dir_dentry,
				      encrypted_and_encoded_name_size - 1);
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	mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
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	if (IS_ERR(lower_dentry)) {
		rc = PTR_ERR(lower_dentry);
		printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
		       "lower_dentry = [%s]\n", __func__, rc,
		       encrypted_and_encoded_name);
		goto out_d_drop;
	}
lookup_and_interpose:
	rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
425
						 ecryptfs_dir_inode,
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						 ecryptfs_nd);
	goto out;
out_d_drop:
	d_drop(ecryptfs_dentry);
430
out:
431
	kfree(encrypted_and_encoded_name);
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	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;
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	fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
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	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(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);
477
	struct dentry *lower_dir_dentry;
478

479
	dget(lower_dentry);
480
	lower_dir_dentry = lock_parent(lower_dentry);
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	rc = vfs_unlink(lower_dir_inode, lower_dentry);
	if (rc) {
483
		printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
484 485
		goto out_unlock;
	}
486
	fsstack_copy_attr_times(dir, lower_dir_inode);
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	dentry->d_inode->i_nlink =
		ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
	dentry->d_inode->i_ctime = dir->i_ctime;
490
	d_drop(dentry);
491
out_unlock:
492
	unlock_dir(lower_dir_dentry);
493
	dput(lower_dentry);
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	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;
	char *encoded_symname;
504 505
	size_t encoded_symlen;
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
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	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	dget(lower_dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
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	mount_crypt_stat = &ecryptfs_superblock_to_private(
		dir->i_sb)->mount_crypt_stat;
	rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
						  &encoded_symlen,
						  NULL,
						  mount_crypt_stat, symname,
						  strlen(symname));
	if (rc)
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		goto out_lock;
	rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
520
			 encoded_symname);
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	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;
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	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
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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;
551 552
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
553 554 555 556 557 558 559 560 561 562 563 564
	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;
565
	int rc;
566 567

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
568
	dget(dentry);
569
	lower_dir_dentry = lock_parent(lower_dentry);
570
	dget(lower_dentry);
571
	rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
572 573 574
	dput(lower_dentry);
	if (!rc)
		d_delete(lower_dentry);
575
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
576 577 578 579
	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
	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;
596
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
597 598
	if (rc)
		goto out;
599 600
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
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
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;
629
	fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
630
	if (new_dir != old_dir)
631
		fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
632 633
out_lock:
	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
634 635
	dput(lower_new_dentry->d_parent);
	dput(lower_old_dentry->d_parent);
636 637 638 639 640 641
	dput(lower_new_dentry);
	dput(lower_old_dentry);
	return rc;
}

static int
642
ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
643 644
{
	char *lower_buf;
645
	size_t lower_bufsiz;
646
	struct dentry *lower_dentry;
647
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
648 649 650 651
	char *plaintext_name;
	size_t plaintext_name_size;
	mm_segment_t old_fs;
	int rc;
652 653

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
A
Al Viro 已提交
654
	if (!lower_dentry->d_inode->i_op->readlink) {
655 656 657
		rc = -EINVAL;
		goto out;
	}
658 659 660 661 662 663 664 665 666 667
	mount_crypt_stat = &ecryptfs_superblock_to_private(
						dentry->d_sb)->mount_crypt_stat;
	/*
	 * If the lower filename is encrypted, it will result in a significantly
	 * longer name.  If needed, truncate the name after decode and decrypt.
	 */
	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
		lower_bufsiz = PATH_MAX;
	else
		lower_bufsiz = bufsiz;
668
	/* Released in this function */
669
	lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
670
	if (lower_buf == NULL) {
671
		printk(KERN_ERR "%s: Out of memory whilst attempting to "
672
		       "kmalloc [%zd] bytes\n", __func__, lower_bufsiz);
673 674 675 676 677 678 679
		rc = -ENOMEM;
		goto out;
	}
	old_fs = get_fs();
	set_fs(get_ds());
	rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
						   (char __user *)lower_buf,
680
						   lower_bufsiz);
681 682
	set_fs(old_fs);
	if (rc >= 0) {
683 684 685 686 687 688 689 690
		rc = ecryptfs_decode_and_decrypt_filename(&plaintext_name,
							  &plaintext_name_size,
							  dentry, lower_buf,
							  rc);
		if (rc) {
			printk(KERN_ERR "%s: Error attempting to decode and "
			       "decrypt filename; rc = [%d]\n", __func__,
				rc);
691 692
			goto out_free_lower_buf;
		}
693 694
		/* Check for bufsiz <= 0 done in sys_readlinkat() */
		rc = copy_to_user(buf, plaintext_name,
695
				  min((size_t) bufsiz, plaintext_name_size));
696 697 698 699 700 701
		if (rc)
			rc = -EFAULT;
		else
			rc = plaintext_name_size;
		kfree(plaintext_name);
		fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode);
702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717
	}
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) {
718
		buf = ERR_PTR(-ENOMEM);
719 720 721 722 723 724
		goto out;
	}
	old_fs = get_fs();
	set_fs(get_ds());
	rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
	set_fs(old_fs);
725 726 727 728
	if (rc < 0) {
		kfree(buf);
		buf = ERR_PTR(rc);
	} else
729
		buf[rc] = '\0';
730
out:
731 732
	nd_set_link(nd, buf);
	return NULL;
733 734 735 736 737
}

static void
ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
{
738 739 740 741 742
	char *buf = nd_get_link(nd);
	if (!IS_ERR(buf)) {
		/* Free the char* */
		kfree(buf);
	}
743 744 745 746 747 748 749
}

/**
 * upper_size_to_lower_size
 * @crypt_stat: Crypt_stat associated with file
 * @upper_size: Size of the upper file
 *
750
 * Calculate the required size of the lower file based on the
751 752 753 754 755 756 757 758 759 760 761
 * 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;

762
	lower_size = crypt_stat->num_header_bytes_at_front;
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
	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;
791
	struct file fake_ecryptfs_file;
792 793 794 795 796 797 798 799 800 801 802 803
	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));
804
	fake_ecryptfs_file.f_path.dentry = dentry;
805 806 807
	/* Released at out_free: label */
	ecryptfs_set_file_private(&fake_ecryptfs_file,
				  kmem_cache_alloc(ecryptfs_file_info_cache,
808
						   GFP_KERNEL));
809 810 811 812 813
	if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
		rc = -ENOMEM;
		goto out;
	}
	lower_dentry = ecryptfs_dentry_to_lower(dentry);
814 815 816
	ecryptfs_set_file_lower(
		&fake_ecryptfs_file,
		ecryptfs_inode_to_private(dentry->d_inode)->lower_file);
817 818
	/* Switch on growing or shrinking file */
	if (new_length > i_size) {
819 820 821 822 823 824 825 826
		char zero[] = { 0x00 };

		/* Write a single 0 at the last position of the file;
		 * this triggers code that will fill in 0's throughout
		 * the intermediate portion of the previous end of the
		 * file and the new and of the file */
		rc = ecryptfs_write(&fake_ecryptfs_file, zero,
				    (new_length - 1), 1);
827
	} else { /* new_length < i_size_read(inode) */
828 829 830 831 832 833 834
		/* We're chopping off all the pages down do the page
		 * in which new_length is located. Fill in the end of
		 * that page from (new_length & ~PAGE_CACHE_MASK) to
		 * PAGE_CACHE_SIZE with zeros. */
		size_t num_zeros = (PAGE_CACHE_SIZE
				    - (new_length & ~PAGE_CACHE_MASK));

835 836 837 838 839 840 841
		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
			rc = vmtruncate(inode, new_length);
			if (rc)
				goto out_free;
			rc = vmtruncate(lower_dentry->d_inode, new_length);
			goto out_free;
		}
842 843 844 845 846 847 848 849 850 851 852
		if (num_zeros) {
			char *zeros_virt;

			zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
			if (!zeros_virt) {
				rc = -ENOMEM;
				goto out_free;
			}
			rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt,
					    new_length, num_zeros);
			kfree(zeros_virt);
853
			if (rc) {
854 855 856
				printk(KERN_ERR "Error attempting to zero out "
				       "the remainder of the end page on "
				       "reducing truncate; rc = [%d]\n", rc);
857
				goto out_free;
858 859
			}
		}
860
		vmtruncate(inode, new_length);
861
		rc = ecryptfs_write_inode_size_to_metadata(inode);
862 863 864 865
		if (rc) {
			printk(KERN_ERR	"Problem with "
			       "ecryptfs_write_inode_size_to_metadata; "
			       "rc = [%d]\n", rc);
866
			goto out_free;
867
		}
868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886
		/* 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);
	}
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
887
ecryptfs_permission(struct inode *inode, int mask)
888
{
889
	return inode_permission(ecryptfs_inode_to_lower(inode), mask);
890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912
}

/**
 * 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;
913 914
	if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
		ecryptfs_init_crypt_stat(crypt_stat);
915 916
	inode = dentry->d_inode;
	lower_inode = ecryptfs_inode_to_lower(inode);
917 918 919 920
	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	mutex_lock(&crypt_stat->cs_mutex);
	if (S_ISDIR(dentry->d_inode->i_mode))
		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
921 922 923
	else if (S_ISREG(dentry->d_inode->i_mode)
		 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
		     || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
924 925 926 927
		struct ecryptfs_mount_crypt_stat *mount_crypt_stat;

		mount_crypt_stat = &ecryptfs_superblock_to_private(
			dentry->d_sb)->mount_crypt_stat;
928
		rc = ecryptfs_read_metadata(dentry);
929
		if (rc) {
930 931 932
			if (!(mount_crypt_stat->flags
			      & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
				rc = -EIO;
933
				printk(KERN_WARNING "Either the lower file "
934
				       "is not in a valid eCryptfs format, "
935 936
				       "or the key could not be retrieved. "
				       "Plaintext passthrough mode is not "
937 938 939 940 941 942 943 944 945
				       "enabled; returning -EIO\n");
				mutex_unlock(&crypt_stat->cs_mutex);
				goto out;
			}
			rc = 0;
			crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
		}
	}
	mutex_unlock(&crypt_stat->cs_mutex);
946 947 948 949 950 951 952 953 954 955 956 957
	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;
	}
958 959 960 961 962 963 964 965

	/*
	 * mode change is for clearing setuid/setgid bits. Allow lower fs
	 * to interpret this in its own way.
	 */
	if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
		ia->ia_valid &= ~ATTR_MODE;

966
	mutex_lock(&lower_dentry->d_inode->i_mutex);
967
	rc = notify_change(lower_dentry, ia);
968
	mutex_unlock(&lower_dentry->d_inode->i_mutex);
969
out:
970
	fsstack_copy_attr_all(inode, lower_inode);
971 972 973
	return rc;
}

974
int
975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993
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;
}

994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011
ssize_t
ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
			void *value, size_t size)
{
	int rc = 0;

	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;
}

A
Adrian Bunk 已提交
1012
static ssize_t
1013 1014 1015
ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
		  size_t size)
{
1016 1017
	return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
				       value, size);
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 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
}

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;
}

1070
const struct inode_operations ecryptfs_symlink_iops = {
1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081
	.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
};

1082
const struct inode_operations ecryptfs_dir_iops = {
1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
	.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
};

1100
const struct inode_operations ecryptfs_main_iops = {
1101 1102 1103 1104 1105 1106 1107
	.permission = ecryptfs_permission,
	.setattr = ecryptfs_setattr,
	.setxattr = ecryptfs_setxattr,
	.getxattr = ecryptfs_getxattr,
	.listxattr = ecryptfs_listxattr,
	.removexattr = ecryptfs_removexattr
};