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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>
29#include <linux/seq_file.h>
Michael Halcrow4981e082007-10-16 01:28:09 -070030#include <linux/file.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070031#include <linux/crypto.h>
32#include "ecryptfs_kernel.h"
33
34struct kmem_cache *ecryptfs_inode_info_cache;
35
36/**
37 * ecryptfs_alloc_inode - allocate an ecryptfs inode
38 * @sb: Pointer to the ecryptfs super block
39 *
40 * Called to bring an inode into existence.
41 *
42 * Only handle allocation, setting up structures should be done in
43 * ecryptfs_read_inode. This is because the kernel, between now and
44 * then, will 0 out the private data pointer.
45 *
46 * Returns a pointer to a newly allocated inode, NULL otherwise
47 */
48static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
49{
Michael Halcrow035241d2007-10-16 01:28:12 -070050 struct ecryptfs_inode_info *inode_info;
Michael Halcrow237fead2006-10-04 02:16:22 -070051 struct inode *inode = NULL;
52
Michael Halcrow035241d2007-10-16 01:28:12 -070053 inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL);
54 if (unlikely(!inode_info))
Michael Halcrow237fead2006-10-04 02:16:22 -070055 goto out;
Michael Halcrow035241d2007-10-16 01:28:12 -070056 ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
57 mutex_init(&inode_info->lower_file_mutex);
58 inode_info->lower_file = NULL;
59 inode = &inode_info->vfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -070060out:
61 return inode;
62}
63
64/**
65 * ecryptfs_destroy_inode
66 * @inode: The ecryptfs inode
67 *
Michael Halcrow4981e082007-10-16 01:28:09 -070068 * This is used during the final destruction of the inode. All
69 * allocation of memory related to the inode, including allocated
70 * memory in the crypt_stat struct, will be released here. This
71 * function also fput()'s the persistent file for the lower inode.
Michael Halcrow237fead2006-10-04 02:16:22 -070072 * There should be no chance that this deallocation will be missed.
73 */
74static void ecryptfs_destroy_inode(struct inode *inode)
75{
76 struct ecryptfs_inode_info *inode_info;
77
78 inode_info = ecryptfs_inode_to_private(inode);
Michael Halcrow4981e082007-10-16 01:28:09 -070079 mutex_lock(&inode_info->lower_file_mutex);
80 if (inode_info->lower_file) {
81 struct dentry *lower_dentry =
82 inode_info->lower_file->f_dentry;
83
84 BUG_ON(!lower_dentry);
85 if (lower_dentry->d_inode) {
86 fput(inode_info->lower_file);
87 inode_info->lower_file = NULL;
88 d_drop(lower_dentry);
Michael Halcrow4981e082007-10-16 01:28:09 -070089 }
90 }
91 mutex_unlock(&inode_info->lower_file_mutex);
Michael Halcrowfcd12832007-10-16 01:28:01 -070092 ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -070093 kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
94}
95
96/**
97 * ecryptfs_init_inode
98 * @inode: The ecryptfs inode
99 *
100 * Set up the ecryptfs inode.
101 */
102void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode)
103{
104 ecryptfs_set_inode_lower(inode, lower_inode);
105 inode->i_ino = lower_inode->i_ino;
106 inode->i_version++;
107 inode->i_op = &ecryptfs_main_iops;
108 inode->i_fop = &ecryptfs_main_fops;
109 inode->i_mapping->a_ops = &ecryptfs_aops;
110}
111
112/**
113 * ecryptfs_put_super
114 * @sb: Pointer to the ecryptfs super block
115 *
116 * Final actions when unmounting a file system.
117 * This will handle deallocation and release of our private data.
118 */
119static void ecryptfs_put_super(struct super_block *sb)
120{
121 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
122
Michael Halcrowfcd12832007-10-16 01:28:01 -0700123 ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700124 kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
125 ecryptfs_set_superblock_private(sb, NULL);
126}
127
128/**
129 * ecryptfs_statfs
130 * @sb: The ecryptfs super block
131 * @buf: The struct kstatfs to fill in with stats
132 *
133 * Get the filesystem statistics. Currently, we let this pass right through
134 * to the lower filesystem and take no action ourselves.
135 */
136static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
137{
138 return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf);
139}
140
141/**
142 * ecryptfs_clear_inode
143 * @inode - The ecryptfs inode
144 *
145 * Called by iput() when the inode reference count reached zero
146 * and the inode is not hashed anywhere. Used to clear anything
147 * that needs to be, before the inode is completely destroyed and put
148 * on the inode free list. We use this to drop out reference to the
149 * lower inode.
150 */
151static void ecryptfs_clear_inode(struct inode *inode)
152{
153 iput(ecryptfs_inode_to_lower(inode));
154}
155
156/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700157 * ecryptfs_show_options
158 *
Eric Sandeen99db6e42008-02-06 01:38:34 -0800159 * Prints the mount options for a given superblock.
160 * Returns zero; does not fail.
Michael Halcrow237fead2006-10-04 02:16:22 -0700161 */
162static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt)
163{
164 struct super_block *sb = mnt->mnt_sb;
Eric Sandeen99db6e42008-02-06 01:38:34 -0800165 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
166 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
167 struct ecryptfs_global_auth_tok *walker;
Michael Halcrow237fead2006-10-04 02:16:22 -0700168
Eric Sandeen99db6e42008-02-06 01:38:34 -0800169 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
170 list_for_each_entry(walker,
171 &mount_crypt_stat->global_auth_tok_list,
172 mount_crypt_stat_list) {
173 seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
Michael Halcrow237fead2006-10-04 02:16:22 -0700174 }
Eric Sandeen99db6e42008-02-06 01:38:34 -0800175 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
176
Eric Sandeen99db6e42008-02-06 01:38:34 -0800177 seq_printf(m, ",ecryptfs_cipher=%s",
178 mount_crypt_stat->global_default_cipher_name);
179
180 if (mount_crypt_stat->global_default_cipher_key_size)
181 seq_printf(m, ",ecryptfs_key_bytes=%zd",
182 mount_crypt_stat->global_default_cipher_key_size);
183 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
184 seq_printf(m, ",ecryptfs_passthrough");
185 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
186 seq_printf(m, ",ecryptfs_xattr_metadata");
187 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
188 seq_printf(m, ",ecryptfs_encrypted_view");
189
190 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700191}
192
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800193const struct super_operations ecryptfs_sops = {
Michael Halcrow237fead2006-10-04 02:16:22 -0700194 .alloc_inode = ecryptfs_alloc_inode,
195 .destroy_inode = ecryptfs_destroy_inode,
196 .drop_inode = generic_delete_inode,
197 .put_super = ecryptfs_put_super,
198 .statfs = ecryptfs_statfs,
199 .remount_fs = NULL,
200 .clear_inode = ecryptfs_clear_inode,
Michael Halcrow237fead2006-10-04 02:16:22 -0700201 .show_options = ecryptfs_show_options
202};