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237fead6 MH |
1 | /** |
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> | |
6cfd0148 | 30 | #include <linux/smp_lock.h> |
4981e081 | 31 | #include <linux/file.h> |
237fead6 MH |
32 | #include <linux/crypto.h> |
33 | #include "ecryptfs_kernel.h" | |
34 | ||
35 | struct 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 | */ | |
49 | static struct inode *ecryptfs_alloc_inode(struct super_block *sb) | |
50 | { | |
035241d3 | 51 | struct ecryptfs_inode_info *inode_info; |
237fead6 MH |
52 | struct inode *inode = NULL; |
53 | ||
035241d3 MH |
54 | inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL); |
55 | if (unlikely(!inode_info)) | |
237fead6 | 56 | goto out; |
035241d3 MH |
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; | |
237fead6 MH |
61 | out: |
62 | return inode; | |
63 | } | |
64 | ||
65 | /** | |
66 | * ecryptfs_destroy_inode | |
67 | * @inode: The ecryptfs inode | |
68 | * | |
4981e081 MH |
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. | |
237fead6 MH |
73 | * There should be no chance that this deallocation will be missed. |
74 | */ | |
75 | static void ecryptfs_destroy_inode(struct inode *inode) | |
76 | { | |
77 | struct ecryptfs_inode_info *inode_info; | |
78 | ||
79 | inode_info = ecryptfs_inode_to_private(inode); | |
4981e081 MH |
80 | mutex_lock(&inode_info->lower_file_mutex); |
81 | 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; | |
89 | d_drop(lower_dentry); | |
4981e081 MH |
90 | } |
91 | } | |
92 | mutex_unlock(&inode_info->lower_file_mutex); | |
fcd12835 | 93 | ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat); |
237fead6 MH |
94 | kmem_cache_free(ecryptfs_inode_info_cache, inode_info); |
95 | } | |
96 | ||
97 | /** | |
98 | * ecryptfs_init_inode | |
99 | * @inode: The ecryptfs inode | |
100 | * | |
101 | * Set up the ecryptfs inode. | |
102 | */ | |
103 | void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode) | |
104 | { | |
105 | ecryptfs_set_inode_lower(inode, lower_inode); | |
106 | inode->i_ino = lower_inode->i_ino; | |
107 | inode->i_version++; | |
108 | inode->i_op = &ecryptfs_main_iops; | |
109 | inode->i_fop = &ecryptfs_main_fops; | |
110 | inode->i_mapping->a_ops = &ecryptfs_aops; | |
111 | } | |
112 | ||
113 | /** | |
114 | * ecryptfs_put_super | |
115 | * @sb: Pointer to the ecryptfs super block | |
116 | * | |
117 | * Final actions when unmounting a file system. | |
118 | * This will handle deallocation and release of our private data. | |
119 | */ | |
120 | static void ecryptfs_put_super(struct super_block *sb) | |
121 | { | |
122 | struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb); | |
123 | ||
6cfd0148 CH |
124 | lock_kernel(); |
125 | ||
fcd12835 | 126 | ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat); |
237fead6 MH |
127 | kmem_cache_free(ecryptfs_sb_info_cache, sb_info); |
128 | ecryptfs_set_superblock_private(sb, NULL); | |
6cfd0148 CH |
129 | |
130 | unlock_kernel(); | |
237fead6 MH |
131 | } |
132 | ||
133 | /** | |
134 | * ecryptfs_statfs | |
135 | * @sb: The ecryptfs super block | |
136 | * @buf: The struct kstatfs to fill in with stats | |
137 | * | |
138 | * Get the filesystem statistics. Currently, we let this pass right through | |
139 | * to the lower filesystem and take no action ourselves. | |
140 | */ | |
141 | static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf) | |
142 | { | |
143 | return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf); | |
144 | } | |
145 | ||
146 | /** | |
147 | * ecryptfs_clear_inode | |
148 | * @inode - The ecryptfs inode | |
149 | * | |
150 | * Called by iput() when the inode reference count reached zero | |
151 | * and the inode is not hashed anywhere. Used to clear anything | |
152 | * that needs to be, before the inode is completely destroyed and put | |
153 | * on the inode free list. We use this to drop out reference to the | |
154 | * lower inode. | |
155 | */ | |
156 | static void ecryptfs_clear_inode(struct inode *inode) | |
157 | { | |
158 | iput(ecryptfs_inode_to_lower(inode)); | |
159 | } | |
160 | ||
237fead6 MH |
161 | /** |
162 | * ecryptfs_show_options | |
163 | * | |
99db6e4a ES |
164 | * Prints the mount options for a given superblock. |
165 | * Returns zero; does not fail. | |
237fead6 MH |
166 | */ |
167 | static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt) | |
168 | { | |
169 | struct super_block *sb = mnt->mnt_sb; | |
99db6e4a ES |
170 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
171 | &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; | |
172 | struct ecryptfs_global_auth_tok *walker; | |
173 | ||
174 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); | |
175 | list_for_each_entry(walker, | |
176 | &mount_crypt_stat->global_auth_tok_list, | |
177 | mount_crypt_stat_list) { | |
3a5203ab TH |
178 | if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK) |
179 | seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig); | |
180 | else | |
181 | seq_printf(m, ",ecryptfs_sig=%s", walker->sig); | |
237fead6 | 182 | } |
99db6e4a ES |
183 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
184 | ||
99db6e4a ES |
185 | seq_printf(m, ",ecryptfs_cipher=%s", |
186 | mount_crypt_stat->global_default_cipher_name); | |
187 | ||
188 | if (mount_crypt_stat->global_default_cipher_key_size) | |
189 | seq_printf(m, ",ecryptfs_key_bytes=%zd", | |
190 | mount_crypt_stat->global_default_cipher_key_size); | |
191 | if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) | |
192 | seq_printf(m, ",ecryptfs_passthrough"); | |
193 | if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) | |
194 | seq_printf(m, ",ecryptfs_xattr_metadata"); | |
195 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
196 | seq_printf(m, ",ecryptfs_encrypted_view"); | |
e77cc8d2 TH |
197 | if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS) |
198 | seq_printf(m, ",ecryptfs_unlink_sigs"); | |
99db6e4a ES |
199 | |
200 | return 0; | |
237fead6 MH |
201 | } |
202 | ||
ee9b6d61 | 203 | const struct super_operations ecryptfs_sops = { |
237fead6 MH |
204 | .alloc_inode = ecryptfs_alloc_inode, |
205 | .destroy_inode = ecryptfs_destroy_inode, | |
206 | .drop_inode = generic_delete_inode, | |
207 | .put_super = ecryptfs_put_super, | |
208 | .statfs = ecryptfs_statfs, | |
209 | .remount_fs = NULL, | |
210 | .clear_inode = ecryptfs_clear_inode, | |
237fead6 MH |
211 | .show_options = ecryptfs_show_options |
212 | }; |