blob: 3042fe123a3426c30dba69e35a622738977bf105 [file] [log] [blame]
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>
33#include "ecryptfs_kernel.h"
34
35struct kmem_cache *ecryptfs_inode_info_cache;
36
37/**
38 * ecryptfs_alloc_inode - allocate an ecryptfs inode
39 * @sb: Pointer to the ecryptfs super block
40 *
41 * Called to bring an inode into existence.
42 *
43 * Only handle allocation, setting up structures should be done in
44 * ecryptfs_read_inode. This is because the kernel, between now and
45 * then, will 0 out the private data pointer.
46 *
47 * Returns a pointer to a newly allocated inode, NULL otherwise
48 */
49static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
50{
Michael Halcrow035241d2007-10-16 01:28:12 -070051 struct ecryptfs_inode_info *inode_info;
Michael Halcrow237fead2006-10-04 02:16:22 -070052 struct inode *inode = NULL;
53
Michael Halcrow035241d2007-10-16 01:28:12 -070054 inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL);
55 if (unlikely(!inode_info))
Michael Halcrow237fead2006-10-04 02:16:22 -070056 goto out;
Michael Halcrow035241d2007-10-16 01:28:12 -070057 ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
58 mutex_init(&inode_info->lower_file_mutex);
59 inode_info->lower_file = NULL;
60 inode = &inode_info->vfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -070061out:
62 return inode;
63}
64
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +110065static void ecryptfs_i_callback(struct rcu_head *head)
66{
67 struct inode *inode = container_of(head, struct inode, i_rcu);
68 struct ecryptfs_inode_info *inode_info;
69 inode_info = ecryptfs_inode_to_private(inode);
70
71 INIT_LIST_HEAD(&inode->i_dentry);
72 kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
73}
74
Michael Halcrow237fead2006-10-04 02:16:22 -070075/**
76 * ecryptfs_destroy_inode
77 * @inode: The ecryptfs inode
78 *
Michael Halcrow4981e082007-10-16 01:28:09 -070079 * This is used during the final destruction of the inode. All
80 * allocation of memory related to the inode, including allocated
81 * memory in the crypt_stat struct, will be released here. This
82 * function also fput()'s the persistent file for the lower inode.
Michael Halcrow237fead2006-10-04 02:16:22 -070083 * There should be no chance that this deallocation will be missed.
84 */
85static void ecryptfs_destroy_inode(struct inode *inode)
86{
87 struct ecryptfs_inode_info *inode_info;
88
89 inode_info = ecryptfs_inode_to_private(inode);
Michael Halcrow4981e082007-10-16 01:28:09 -070090 if (inode_info->lower_file) {
91 struct dentry *lower_dentry =
92 inode_info->lower_file->f_dentry;
93
94 BUG_ON(!lower_dentry);
95 if (lower_dentry->d_inode) {
96 fput(inode_info->lower_file);
97 inode_info->lower_file = NULL;
Michael Halcrow4981e082007-10-16 01:28:09 -070098 }
99 }
Michael Halcrowfcd12832007-10-16 01:28:01 -0700100 ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
Nick Pigginfa0d7e3d2011-01-07 17:49:49 +1100101 call_rcu(&inode->i_rcu, ecryptfs_i_callback);
Michael Halcrow237fead2006-10-04 02:16:22 -0700102}
103
104/**
105 * ecryptfs_init_inode
106 * @inode: The ecryptfs inode
107 *
108 * Set up the ecryptfs inode.
109 */
110void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode)
111{
112 ecryptfs_set_inode_lower(inode, lower_inode);
113 inode->i_ino = lower_inode->i_ino;
114 inode->i_version++;
115 inode->i_op = &ecryptfs_main_iops;
116 inode->i_fop = &ecryptfs_main_fops;
117 inode->i_mapping->a_ops = &ecryptfs_aops;
118}
119
120/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700121 * ecryptfs_statfs
122 * @sb: The ecryptfs super block
123 * @buf: The struct kstatfs to fill in with stats
124 *
125 * Get the filesystem statistics. Currently, we let this pass right through
126 * to the lower filesystem and take no action ourselves.
127 */
128static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
129{
Christoph Hellwigebabe9a2010-07-07 18:53:11 +0200130 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
131
132 if (!lower_dentry->d_sb->s_op->statfs)
133 return -ENOSYS;
134 return lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
Michael Halcrow237fead2006-10-04 02:16:22 -0700135}
136
137/**
Al Virob57922d2010-06-07 14:34:48 -0400138 * ecryptfs_evict_inode
Michael Halcrow237fead2006-10-04 02:16:22 -0700139 * @inode - The ecryptfs inode
140 *
141 * Called by iput() when the inode reference count reached zero
142 * and the inode is not hashed anywhere. Used to clear anything
143 * that needs to be, before the inode is completely destroyed and put
144 * on the inode free list. We use this to drop out reference to the
145 * lower inode.
146 */
Al Virob57922d2010-06-07 14:34:48 -0400147static void ecryptfs_evict_inode(struct inode *inode)
Michael Halcrow237fead2006-10-04 02:16:22 -0700148{
Al Virob57922d2010-06-07 14:34:48 -0400149 truncate_inode_pages(&inode->i_data, 0);
150 end_writeback(inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700151 iput(ecryptfs_inode_to_lower(inode));
152}
153
154/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700155 * ecryptfs_show_options
156 *
Eric Sandeen99db6e42008-02-06 01:38:34 -0800157 * Prints the mount options for a given superblock.
158 * Returns zero; does not fail.
Michael Halcrow237fead2006-10-04 02:16:22 -0700159 */
160static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt)
161{
162 struct super_block *sb = mnt->mnt_sb;
Eric Sandeen99db6e42008-02-06 01:38:34 -0800163 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
164 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
165 struct ecryptfs_global_auth_tok *walker;
Michael Halcrow237fead2006-10-04 02:16:22 -0700166
Eric Sandeen99db6e42008-02-06 01:38:34 -0800167 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
168 list_for_each_entry(walker,
169 &mount_crypt_stat->global_auth_tok_list,
170 mount_crypt_stat_list) {
Tyler Hicks3a5203a2009-03-16 12:35:12 -0500171 if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK)
172 seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig);
173 else
174 seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
Michael Halcrow237fead2006-10-04 02:16:22 -0700175 }
Eric Sandeen99db6e42008-02-06 01:38:34 -0800176 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
177
Eric Sandeen99db6e42008-02-06 01:38:34 -0800178 seq_printf(m, ",ecryptfs_cipher=%s",
179 mount_crypt_stat->global_default_cipher_name);
180
181 if (mount_crypt_stat->global_default_cipher_key_size)
182 seq_printf(m, ",ecryptfs_key_bytes=%zd",
183 mount_crypt_stat->global_default_cipher_key_size);
184 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
185 seq_printf(m, ",ecryptfs_passthrough");
186 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
187 seq_printf(m, ",ecryptfs_xattr_metadata");
188 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
189 seq_printf(m, ",ecryptfs_encrypted_view");
Tyler Hickse77cc8d2009-04-22 04:08:46 -0500190 if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS)
191 seq_printf(m, ",ecryptfs_unlink_sigs");
Tyler Hicks8747f952010-10-15 16:43:41 -0500192 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
193 seq_printf(m, ",ecryptfs_mount_auth_tok_only");
Eric Sandeen99db6e42008-02-06 01:38:34 -0800194
195 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700196}
197
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800198const struct super_operations ecryptfs_sops = {
Michael Halcrow237fead2006-10-04 02:16:22 -0700199 .alloc_inode = ecryptfs_alloc_inode,
200 .destroy_inode = ecryptfs_destroy_inode,
201 .drop_inode = generic_delete_inode,
Michael Halcrow237fead2006-10-04 02:16:22 -0700202 .statfs = ecryptfs_statfs,
203 .remount_fs = NULL,
Al Virob57922d2010-06-07 14:34:48 -0400204 .evict_inode = ecryptfs_evict_inode,
Michael Halcrow237fead2006-10-04 02:16:22 -0700205 .show_options = ecryptfs_show_options
206};