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Michael Halcrow237fead2006-10-04 02:16:22 -07001/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2003 Erez Zadok
5 * Copyright (C) 2001-2003 Stony Brook University
6 * Copyright (C) 2004-2006 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8 * Michael C. Thompson <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/fs.h>
27#include <linux/mount.h>
28#include <linux/key.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090029#include <linux/slab.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070030#include <linux/seq_file.h>
Michael Halcrow4981e082007-10-16 01:28:09 -070031#include <linux/file.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070032#include <linux/crypto.h>
Tyler Hicks4a266202011-11-05 13:45:08 -040033#include <linux/statfs.h>
34#include <linux/magic.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070035#include "ecryptfs_kernel.h"
36
37struct kmem_cache *ecryptfs_inode_info_cache;
38
39/**
40 * ecryptfs_alloc_inode - allocate an ecryptfs inode
41 * @sb: Pointer to the ecryptfs super block
42 *
43 * Called to bring an inode into existence.
44 *
45 * Only handle allocation, setting up structures should be done in
46 * ecryptfs_read_inode. This is because the kernel, between now and
47 * then, will 0 out the private data pointer.
48 *
49 * Returns a pointer to a newly allocated inode, NULL otherwise
50 */
51static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
52{
Michael Halcrow035241d2007-10-16 01:28:12 -070053 struct ecryptfs_inode_info *inode_info;
Michael Halcrow237fead2006-10-04 02:16:22 -070054 struct inode *inode = NULL;
55
Michael Halcrow035241d2007-10-16 01:28:12 -070056 inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL);
57 if (unlikely(!inode_info))
Michael Halcrow237fead2006-10-04 02:16:22 -070058 goto out;
Michael Halcrow035241d2007-10-16 01:28:12 -070059 ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
Tyler Hicks332ab162011-04-14 15:35:11 -050060 mutex_init(&inode_info->lower_file_mutex);
61 atomic_set(&inode_info->lower_file_count, 0);
Michael Halcrow035241d2007-10-16 01:28:12 -070062 inode_info->lower_file = NULL;
63 inode = &inode_info->vfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -070064out:
65 return inode;
66}
67
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +110068static void ecryptfs_i_callback(struct rcu_head *head)
69{
70 struct inode *inode = container_of(head, struct inode, i_rcu);
71 struct ecryptfs_inode_info *inode_info;
72 inode_info = ecryptfs_inode_to_private(inode);
73
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +110074 kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
75}
76
Michael Halcrow237fead2006-10-04 02:16:22 -070077/**
78 * ecryptfs_destroy_inode
79 * @inode: The ecryptfs inode
80 *
Michael Halcrow4981e082007-10-16 01:28:09 -070081 * This is used during the final destruction of the inode. All
82 * allocation of memory related to the inode, including allocated
Tyler Hicks332ab162011-04-14 15:35:11 -050083 * memory in the crypt_stat struct, will be released here.
Michael Halcrow237fead2006-10-04 02:16:22 -070084 * There should be no chance that this deallocation will be missed.
85 */
86static void ecryptfs_destroy_inode(struct inode *inode)
87{
88 struct ecryptfs_inode_info *inode_info;
89
90 inode_info = ecryptfs_inode_to_private(inode);
Tyler Hicks332ab162011-04-14 15:35:11 -050091 BUG_ON(inode_info->lower_file);
Michael Halcrowfcd12832007-10-16 01:28:01 -070092 ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +110093 call_rcu(&inode->i_rcu, ecryptfs_i_callback);
Michael Halcrow237fead2006-10-04 02:16:22 -070094}
95
96/**
Michael Halcrow237fead2006-10-04 02:16:22 -070097 * ecryptfs_statfs
98 * @sb: The ecryptfs super block
99 * @buf: The struct kstatfs to fill in with stats
100 *
101 * Get the filesystem statistics. Currently, we let this pass right through
102 * to the lower filesystem and take no action ourselves.
103 */
104static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
105{
Christoph Hellwigebabe9a2010-07-07 18:53:11 +0200106 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
Tyler Hicks4a266202011-11-05 13:45:08 -0400107 int rc;
Christoph Hellwigebabe9a2010-07-07 18:53:11 +0200108
109 if (!lower_dentry->d_sb->s_op->statfs)
110 return -ENOSYS;
Tyler Hicks4a266202011-11-05 13:45:08 -0400111
112 rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
113 if (rc)
114 return rc;
115
116 buf->f_type = ECRYPTFS_SUPER_MAGIC;
117 rc = ecryptfs_set_f_namelen(&buf->f_namelen, buf->f_namelen,
118 &ecryptfs_superblock_to_private(dentry->d_sb)->mount_crypt_stat);
119
120 return rc;
Michael Halcrow237fead2006-10-04 02:16:22 -0700121}
122
123/**
Al Virob57922d2010-06-07 14:34:48 -0400124 * ecryptfs_evict_inode
Michael Halcrow237fead2006-10-04 02:16:22 -0700125 * @inode - The ecryptfs inode
126 *
127 * Called by iput() when the inode reference count reached zero
128 * and the inode is not hashed anywhere. Used to clear anything
129 * that needs to be, before the inode is completely destroyed and put
130 * on the inode free list. We use this to drop out reference to the
131 * lower inode.
132 */
Al Virob57922d2010-06-07 14:34:48 -0400133static void ecryptfs_evict_inode(struct inode *inode)
Michael Halcrow237fead2006-10-04 02:16:22 -0700134{
Al Virob57922d2010-06-07 14:34:48 -0400135 truncate_inode_pages(&inode->i_data, 0);
136 end_writeback(inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700137 iput(ecryptfs_inode_to_lower(inode));
138}
139
140/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700141 * ecryptfs_show_options
142 *
Eric Sandeen99db6e42008-02-06 01:38:34 -0800143 * Prints the mount options for a given superblock.
144 * Returns zero; does not fail.
Michael Halcrow237fead2006-10-04 02:16:22 -0700145 */
Al Viro34c80b12011-12-08 21:32:45 -0500146static int ecryptfs_show_options(struct seq_file *m, struct dentry *root)
Michael Halcrow237fead2006-10-04 02:16:22 -0700147{
Al Viro34c80b12011-12-08 21:32:45 -0500148 struct super_block *sb = root->d_sb;
Eric Sandeen99db6e42008-02-06 01:38:34 -0800149 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
150 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
151 struct ecryptfs_global_auth_tok *walker;
Michael Halcrow237fead2006-10-04 02:16:22 -0700152
Eric Sandeen99db6e42008-02-06 01:38:34 -0800153 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
154 list_for_each_entry(walker,
155 &mount_crypt_stat->global_auth_tok_list,
156 mount_crypt_stat_list) {
Tyler Hicks3a5203a2009-03-16 12:35:12 -0500157 if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK)
158 seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig);
159 else
160 seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
Michael Halcrow237fead2006-10-04 02:16:22 -0700161 }
Eric Sandeen99db6e42008-02-06 01:38:34 -0800162 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
163
Eric Sandeen99db6e42008-02-06 01:38:34 -0800164 seq_printf(m, ",ecryptfs_cipher=%s",
165 mount_crypt_stat->global_default_cipher_name);
166
167 if (mount_crypt_stat->global_default_cipher_key_size)
168 seq_printf(m, ",ecryptfs_key_bytes=%zd",
169 mount_crypt_stat->global_default_cipher_key_size);
170 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
171 seq_printf(m, ",ecryptfs_passthrough");
172 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
173 seq_printf(m, ",ecryptfs_xattr_metadata");
174 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
175 seq_printf(m, ",ecryptfs_encrypted_view");
Tyler Hickse77cc8d2009-04-22 04:08:46 -0500176 if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS)
177 seq_printf(m, ",ecryptfs_unlink_sigs");
Tyler Hicks8747f952010-10-15 16:43:41 -0500178 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
179 seq_printf(m, ",ecryptfs_mount_auth_tok_only");
Eric Sandeen99db6e42008-02-06 01:38:34 -0800180
181 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700182}
183
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800184const struct super_operations ecryptfs_sops = {
Michael Halcrow237fead2006-10-04 02:16:22 -0700185 .alloc_inode = ecryptfs_alloc_inode,
186 .destroy_inode = ecryptfs_destroy_inode,
Thieu Le57db4e82011-03-08 16:26:03 -0800187 .drop_inode = generic_drop_inode,
Michael Halcrow237fead2006-10-04 02:16:22 -0700188 .statfs = ecryptfs_statfs,
189 .remount_fs = NULL,
Al Virob57922d2010-06-07 14:34:48 -0400190 .evict_inode = ecryptfs_evict_inode,
Michael Halcrow237fead2006-10-04 02:16:22 -0700191 .show_options = ecryptfs_show_options
192};