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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>
Christoph Hellwig6cfd0142009-05-05 15:40:36 +020030#include <linux/smp_lock.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
65/**
66 * ecryptfs_destroy_inode
67 * @inode: The ecryptfs inode
68 *
Michael Halcrow4981e082007-10-16 01:28:09 -070069 * This is used during the final destruction of the inode. All
70 * allocation of memory related to the inode, including allocated
71 * memory in the crypt_stat struct, will be released here. This
72 * function also fput()'s the persistent file for the lower inode.
Michael Halcrow237fead2006-10-04 02:16:22 -070073 * There should be no chance that this deallocation will be missed.
74 */
75static void ecryptfs_destroy_inode(struct inode *inode)
76{
77 struct ecryptfs_inode_info *inode_info;
78
79 inode_info = ecryptfs_inode_to_private(inode);
Michael Halcrow4981e082007-10-16 01:28:09 -070080 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 }
Michael Halcrowfcd12832007-10-16 01:28:01 -070091 ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -070092 kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
93}
94
95/**
96 * ecryptfs_init_inode
97 * @inode: The ecryptfs inode
98 *
99 * Set up the ecryptfs inode.
100 */
101void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode)
102{
103 ecryptfs_set_inode_lower(inode, lower_inode);
104 inode->i_ino = lower_inode->i_ino;
105 inode->i_version++;
106 inode->i_op = &ecryptfs_main_iops;
107 inode->i_fop = &ecryptfs_main_fops;
108 inode->i_mapping->a_ops = &ecryptfs_aops;
109}
110
111/**
112 * ecryptfs_put_super
113 * @sb: Pointer to the ecryptfs super block
114 *
115 * Final actions when unmounting a file system.
116 * This will handle deallocation and release of our private data.
117 */
118static void ecryptfs_put_super(struct super_block *sb)
119{
120 struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
121
Christoph Hellwig6cfd0142009-05-05 15:40:36 +0200122 lock_kernel();
123
Michael Halcrowfcd12832007-10-16 01:28:01 -0700124 ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
Michael Halcrow237fead2006-10-04 02:16:22 -0700125 kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
126 ecryptfs_set_superblock_private(sb, NULL);
Christoph Hellwig6cfd0142009-05-05 15:40:36 +0200127
128 unlock_kernel();
Michael Halcrow237fead2006-10-04 02:16:22 -0700129}
130
131/**
132 * ecryptfs_statfs
133 * @sb: The ecryptfs super block
134 * @buf: The struct kstatfs to fill in with stats
135 *
136 * Get the filesystem statistics. Currently, we let this pass right through
137 * to the lower filesystem and take no action ourselves.
138 */
139static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
140{
141 return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf);
142}
143
144/**
145 * ecryptfs_clear_inode
146 * @inode - The ecryptfs inode
147 *
148 * Called by iput() when the inode reference count reached zero
149 * and the inode is not hashed anywhere. Used to clear anything
150 * that needs to be, before the inode is completely destroyed and put
151 * on the inode free list. We use this to drop out reference to the
152 * lower inode.
153 */
154static void ecryptfs_clear_inode(struct inode *inode)
155{
156 iput(ecryptfs_inode_to_lower(inode));
157}
158
159/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700160 * ecryptfs_show_options
161 *
Eric Sandeen99db6e42008-02-06 01:38:34 -0800162 * Prints the mount options for a given superblock.
163 * Returns zero; does not fail.
Michael Halcrow237fead2006-10-04 02:16:22 -0700164 */
165static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt)
166{
167 struct super_block *sb = mnt->mnt_sb;
Eric Sandeen99db6e42008-02-06 01:38:34 -0800168 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
169 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
170 struct ecryptfs_global_auth_tok *walker;
Michael Halcrow237fead2006-10-04 02:16:22 -0700171
Eric Sandeen99db6e42008-02-06 01:38:34 -0800172 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
173 list_for_each_entry(walker,
174 &mount_crypt_stat->global_auth_tok_list,
175 mount_crypt_stat_list) {
Tyler Hicks3a5203a2009-03-16 12:35:12 -0500176 if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK)
177 seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig);
178 else
179 seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
Michael Halcrow237fead2006-10-04 02:16:22 -0700180 }
Eric Sandeen99db6e42008-02-06 01:38:34 -0800181 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
182
Eric Sandeen99db6e42008-02-06 01:38:34 -0800183 seq_printf(m, ",ecryptfs_cipher=%s",
184 mount_crypt_stat->global_default_cipher_name);
185
186 if (mount_crypt_stat->global_default_cipher_key_size)
187 seq_printf(m, ",ecryptfs_key_bytes=%zd",
188 mount_crypt_stat->global_default_cipher_key_size);
189 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
190 seq_printf(m, ",ecryptfs_passthrough");
191 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
192 seq_printf(m, ",ecryptfs_xattr_metadata");
193 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
194 seq_printf(m, ",ecryptfs_encrypted_view");
Tyler Hickse77cc8d2009-04-22 04:08:46 -0500195 if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS)
196 seq_printf(m, ",ecryptfs_unlink_sigs");
Eric Sandeen99db6e42008-02-06 01:38:34 -0800197
198 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700199}
200
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800201const struct super_operations ecryptfs_sops = {
Michael Halcrow237fead2006-10-04 02:16:22 -0700202 .alloc_inode = ecryptfs_alloc_inode,
203 .destroy_inode = ecryptfs_destroy_inode,
204 .drop_inode = generic_delete_inode,
205 .put_super = ecryptfs_put_super,
206 .statfs = ecryptfs_statfs,
207 .remount_fs = NULL,
208 .clear_inode = ecryptfs_clear_inode,
Michael Halcrow237fead2006-10-04 02:16:22 -0700209 .show_options = ecryptfs_show_options
210};