2 * eCryptfs: Linux filesystem encryption layer
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>
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.
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.
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
27 #include <linux/mount.h>
28 #include <linux/key.h>
29 #include <linux/slab.h>
30 #include <linux/seq_file.h>
31 #include <linux/file.h>
32 #include <linux/crypto.h>
33 #include <linux/statfs.h>
34 #include <linux/magic.h>
35 #include "ecryptfs_kernel.h"
37 struct kmem_cache *ecryptfs_inode_info_cache;
40 * ecryptfs_alloc_inode - allocate an ecryptfs inode
41 * @sb: Pointer to the ecryptfs super block
43 * Called to bring an inode into existence.
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.
49 * Returns a pointer to a newly allocated inode, NULL otherwise
51 static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
53 struct ecryptfs_inode_info *inode_info;
54 struct inode *inode = NULL;
56 inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL);
57 if (unlikely(!inode_info))
59 ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
60 mutex_init(&inode_info->lower_file_mutex);
61 atomic_set(&inode_info->lower_file_count, 0);
62 inode_info->lower_file = NULL;
63 inode = &inode_info->vfs_inode;
68 static void ecryptfs_i_callback(struct rcu_head *head)
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);
74 kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
78 * ecryptfs_destroy_inode
79 * @inode: The ecryptfs inode
81 * This is used during the final destruction of the inode. All
82 * allocation of memory related to the inode, including allocated
83 * memory in the crypt_stat struct, will be released here.
84 * There should be no chance that this deallocation will be missed.
86 static void ecryptfs_destroy_inode(struct inode *inode)
88 struct ecryptfs_inode_info *inode_info;
90 inode_info = ecryptfs_inode_to_private(inode);
91 BUG_ON(inode_info->lower_file);
92 ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
93 call_rcu(&inode->i_rcu, ecryptfs_i_callback);
98 * @sb: The ecryptfs super block
99 * @buf: The struct kstatfs to fill in with stats
101 * Get the filesystem statistics. Currently, we let this pass right through
102 * to the lower filesystem and take no action ourselves.
104 static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
106 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
109 if (!lower_dentry->d_sb->s_op->statfs)
112 rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
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);
124 * ecryptfs_evict_inode
125 * @inode - The ecryptfs inode
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
133 static void ecryptfs_evict_inode(struct inode *inode)
135 truncate_inode_pages_final(&inode->i_data);
137 iput(ecryptfs_inode_to_lower(inode));
141 * ecryptfs_show_options
143 * Prints the mount options for a given superblock.
144 * Returns zero; does not fail.
146 static int ecryptfs_show_options(struct seq_file *m, struct dentry *root)
148 struct super_block *sb = root->d_sb;
149 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
150 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
151 struct ecryptfs_global_auth_tok *walker;
153 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) {
157 if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK)
158 seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig);
160 seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
162 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
164 seq_printf(m, ",ecryptfs_cipher=%s",
165 mount_crypt_stat->global_default_cipher_name);
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");
176 if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS)
177 seq_printf(m, ",ecryptfs_unlink_sigs");
178 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
179 seq_printf(m, ",ecryptfs_mount_auth_tok_only");
184 const struct super_operations ecryptfs_sops = {
185 .alloc_inode = ecryptfs_alloc_inode,
186 .destroy_inode = ecryptfs_destroy_inode,
187 .statfs = ecryptfs_statfs,
189 .evict_inode = ecryptfs_evict_inode,
190 .show_options = ecryptfs_show_options