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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>
Christoph Hellwig6cfd0142009-05-05 15:40:36 +020031#include <linux/smp_lock.h>
Michael Halcrow4981e082007-10-16 01:28:09 -070032#include <linux/file.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070033#include <linux/crypto.h>
34#include "ecryptfs_kernel.h"
35
36struct kmem_cache *ecryptfs_inode_info_cache;
37
38/**
39 * ecryptfs_alloc_inode - allocate an ecryptfs inode
40 * @sb: Pointer to the ecryptfs super block
41 *
42 * Called to bring an inode into existence.
43 *
44 * Only handle allocation, setting up structures should be done in
45 * ecryptfs_read_inode. This is because the kernel, between now and
46 * then, will 0 out the private data pointer.
47 *
48 * Returns a pointer to a newly allocated inode, NULL otherwise
49 */
50static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
51{
Michael Halcrow035241d2007-10-16 01:28:12 -070052 struct ecryptfs_inode_info *inode_info;
Michael Halcrow237fead2006-10-04 02:16:22 -070053 struct inode *inode = NULL;
54
Michael Halcrow035241d2007-10-16 01:28:12 -070055 inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL);
56 if (unlikely(!inode_info))
Michael Halcrow237fead2006-10-04 02:16:22 -070057 goto out;
Michael Halcrow035241d2007-10-16 01:28:12 -070058 ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
59 mutex_init(&inode_info->lower_file_mutex);
60 inode_info->lower_file = NULL;
61 inode = &inode_info->vfs_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -070062out:
63 return inode;
64}
65
66/**
67 * ecryptfs_destroy_inode
68 * @inode: The ecryptfs inode
69 *
Michael Halcrow4981e082007-10-16 01:28:09 -070070 * This is used during the final destruction of the inode. All
71 * allocation of memory related to the inode, including allocated
72 * memory in the crypt_stat struct, will be released here. This
73 * function also fput()'s the persistent file for the lower inode.
Michael Halcrow237fead2006-10-04 02:16:22 -070074 * There should be no chance that this deallocation will be missed.
75 */
76static void ecryptfs_destroy_inode(struct inode *inode)
77{
78 struct ecryptfs_inode_info *inode_info;
79
80 inode_info = ecryptfs_inode_to_private(inode);
Michael Halcrow4981e082007-10-16 01:28:09 -070081 if (inode_info->lower_file) {
82 struct dentry *lower_dentry =
83 inode_info->lower_file->f_dentry;
84
85 BUG_ON(!lower_dentry);
86 if (lower_dentry->d_inode) {
87 fput(inode_info->lower_file);
88 inode_info->lower_file = NULL;
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/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700112 * ecryptfs_statfs
113 * @sb: The ecryptfs super block
114 * @buf: The struct kstatfs to fill in with stats
115 *
116 * Get the filesystem statistics. Currently, we let this pass right through
117 * to the lower filesystem and take no action ourselves.
118 */
119static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
120{
Christoph Hellwigebabe9a2010-07-07 18:53:11 +0200121 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
122
123 if (!lower_dentry->d_sb->s_op->statfs)
124 return -ENOSYS;
125 return lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
Michael Halcrow237fead2006-10-04 02:16:22 -0700126}
127
128/**
Al Virob57922d2010-06-07 14:34:48 -0400129 * ecryptfs_evict_inode
Michael Halcrow237fead2006-10-04 02:16:22 -0700130 * @inode - The ecryptfs inode
131 *
132 * Called by iput() when the inode reference count reached zero
133 * and the inode is not hashed anywhere. Used to clear anything
134 * that needs to be, before the inode is completely destroyed and put
135 * on the inode free list. We use this to drop out reference to the
136 * lower inode.
137 */
Al Virob57922d2010-06-07 14:34:48 -0400138static void ecryptfs_evict_inode(struct inode *inode)
Michael Halcrow237fead2006-10-04 02:16:22 -0700139{
Al Virob57922d2010-06-07 14:34:48 -0400140 truncate_inode_pages(&inode->i_data, 0);
141 end_writeback(inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700142 iput(ecryptfs_inode_to_lower(inode));
143}
144
145/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700146 * ecryptfs_show_options
147 *
Eric Sandeen99db6e42008-02-06 01:38:34 -0800148 * Prints the mount options for a given superblock.
149 * Returns zero; does not fail.
Michael Halcrow237fead2006-10-04 02:16:22 -0700150 */
151static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt)
152{
153 struct super_block *sb = mnt->mnt_sb;
Eric Sandeen99db6e42008-02-06 01:38:34 -0800154 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
155 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
156 struct ecryptfs_global_auth_tok *walker;
Michael Halcrow237fead2006-10-04 02:16:22 -0700157
Eric Sandeen99db6e42008-02-06 01:38:34 -0800158 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
159 list_for_each_entry(walker,
160 &mount_crypt_stat->global_auth_tok_list,
161 mount_crypt_stat_list) {
Tyler Hicks3a5203a2009-03-16 12:35:12 -0500162 if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK)
163 seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig);
164 else
165 seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
Michael Halcrow237fead2006-10-04 02:16:22 -0700166 }
Eric Sandeen99db6e42008-02-06 01:38:34 -0800167 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
168
Eric Sandeen99db6e42008-02-06 01:38:34 -0800169 seq_printf(m, ",ecryptfs_cipher=%s",
170 mount_crypt_stat->global_default_cipher_name);
171
172 if (mount_crypt_stat->global_default_cipher_key_size)
173 seq_printf(m, ",ecryptfs_key_bytes=%zd",
174 mount_crypt_stat->global_default_cipher_key_size);
175 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
176 seq_printf(m, ",ecryptfs_passthrough");
177 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
178 seq_printf(m, ",ecryptfs_xattr_metadata");
179 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
180 seq_printf(m, ",ecryptfs_encrypted_view");
Tyler Hickse77cc8d2009-04-22 04:08:46 -0500181 if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS)
182 seq_printf(m, ",ecryptfs_unlink_sigs");
Eric Sandeen99db6e42008-02-06 01:38:34 -0800183
184 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700185}
186
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800187const struct super_operations ecryptfs_sops = {
Michael Halcrow237fead2006-10-04 02:16:22 -0700188 .alloc_inode = ecryptfs_alloc_inode,
189 .destroy_inode = ecryptfs_destroy_inode,
190 .drop_inode = generic_delete_inode,
Michael Halcrow237fead2006-10-04 02:16:22 -0700191 .statfs = ecryptfs_statfs,
192 .remount_fs = NULL,
Al Virob57922d2010-06-07 14:34:48 -0400193 .evict_inode = ecryptfs_evict_inode,
Michael Halcrow237fead2006-10-04 02:16:22 -0700194 .show_options = ecryptfs_show_options
195};