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 "ecryptfs_kernel.h"
35 struct kmem_cache
*ecryptfs_inode_info_cache
;
38 * ecryptfs_alloc_inode - allocate an ecryptfs inode
39 * @sb: Pointer to the ecryptfs super block
41 * Called to bring an inode into existence.
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.
47 * Returns a pointer to a newly allocated inode, NULL otherwise
49 static struct inode
*ecryptfs_alloc_inode(struct super_block
*sb
)
51 struct ecryptfs_inode_info
*inode_info
;
52 struct inode
*inode
= NULL
;
54 inode_info
= kmem_cache_alloc(ecryptfs_inode_info_cache
, GFP_KERNEL
);
55 if (unlikely(!inode_info
))
57 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
;
66 * ecryptfs_destroy_inode
67 * @inode: The ecryptfs inode
69 * 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.
73 * There should be no chance that this deallocation will be missed.
75 static void ecryptfs_destroy_inode(struct inode
*inode
)
77 struct ecryptfs_inode_info
*inode_info
;
79 inode_info
= ecryptfs_inode_to_private(inode
);
80 if (inode_info
->lower_file
) {
81 struct dentry
*lower_dentry
=
82 inode_info
->lower_file
->f_dentry
;
84 BUG_ON(!lower_dentry
);
85 if (lower_dentry
->d_inode
) {
86 fput(inode_info
->lower_file
);
87 inode_info
->lower_file
= NULL
;
90 ecryptfs_destroy_crypt_stat(&inode_info
->crypt_stat
);
91 kmem_cache_free(ecryptfs_inode_info_cache
, inode_info
);
96 * @inode: The ecryptfs inode
98 * Set up the ecryptfs inode.
100 void ecryptfs_init_inode(struct inode
*inode
, struct inode
*lower_inode
)
102 ecryptfs_set_inode_lower(inode
, lower_inode
);
103 inode
->i_ino
= lower_inode
->i_ino
;
105 inode
->i_op
= &ecryptfs_main_iops
;
106 inode
->i_fop
= &ecryptfs_main_fops
;
107 inode
->i_mapping
->a_ops
= &ecryptfs_aops
;
112 * @sb: The ecryptfs super block
113 * @buf: The struct kstatfs to fill in with stats
115 * Get the filesystem statistics. Currently, we let this pass right through
116 * to the lower filesystem and take no action ourselves.
118 static int ecryptfs_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
120 struct dentry
*lower_dentry
= ecryptfs_dentry_to_lower(dentry
);
122 if (!lower_dentry
->d_sb
->s_op
->statfs
)
124 return lower_dentry
->d_sb
->s_op
->statfs(lower_dentry
, buf
);
128 * ecryptfs_evict_inode
129 * @inode - The ecryptfs inode
131 * Called by iput() when the inode reference count reached zero
132 * and the inode is not hashed anywhere. Used to clear anything
133 * that needs to be, before the inode is completely destroyed and put
134 * on the inode free list. We use this to drop out reference to the
137 static void ecryptfs_evict_inode(struct inode
*inode
)
139 truncate_inode_pages(&inode
->i_data
, 0);
140 end_writeback(inode
);
141 iput(ecryptfs_inode_to_lower(inode
));
145 * ecryptfs_show_options
147 * Prints the mount options for a given superblock.
148 * Returns zero; does not fail.
150 static int ecryptfs_show_options(struct seq_file
*m
, struct vfsmount
*mnt
)
152 struct super_block
*sb
= mnt
->mnt_sb
;
153 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
=
154 &ecryptfs_superblock_to_private(sb
)->mount_crypt_stat
;
155 struct ecryptfs_global_auth_tok
*walker
;
157 mutex_lock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
158 list_for_each_entry(walker
,
159 &mount_crypt_stat
->global_auth_tok_list
,
160 mount_crypt_stat_list
) {
161 if (walker
->flags
& ECRYPTFS_AUTH_TOK_FNEK
)
162 seq_printf(m
, ",ecryptfs_fnek_sig=%s", walker
->sig
);
164 seq_printf(m
, ",ecryptfs_sig=%s", walker
->sig
);
166 mutex_unlock(&mount_crypt_stat
->global_auth_tok_list_mutex
);
168 seq_printf(m
, ",ecryptfs_cipher=%s",
169 mount_crypt_stat
->global_default_cipher_name
);
171 if (mount_crypt_stat
->global_default_cipher_key_size
)
172 seq_printf(m
, ",ecryptfs_key_bytes=%zd",
173 mount_crypt_stat
->global_default_cipher_key_size
);
174 if (mount_crypt_stat
->flags
& ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED
)
175 seq_printf(m
, ",ecryptfs_passthrough");
176 if (mount_crypt_stat
->flags
& ECRYPTFS_XATTR_METADATA_ENABLED
)
177 seq_printf(m
, ",ecryptfs_xattr_metadata");
178 if (mount_crypt_stat
->flags
& ECRYPTFS_ENCRYPTED_VIEW_ENABLED
)
179 seq_printf(m
, ",ecryptfs_encrypted_view");
180 if (mount_crypt_stat
->flags
& ECRYPTFS_UNLINK_SIGS
)
181 seq_printf(m
, ",ecryptfs_unlink_sigs");
182 if (mount_crypt_stat
->flags
& ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY
)
183 seq_printf(m
, ",ecryptfs_mount_auth_tok_only");
188 const struct super_operations ecryptfs_sops
= {
189 .alloc_inode
= ecryptfs_alloc_inode
,
190 .destroy_inode
= ecryptfs_destroy_inode
,
191 .drop_inode
= generic_delete_inode
,
192 .statfs
= ecryptfs_statfs
,
194 .evict_inode
= ecryptfs_evict_inode
,
195 .show_options
= ecryptfs_show_options