1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * eCryptfs: Linux filesystem encryption layer |
4 | * |
5 | * Copyright (C) 1997-2003 Erez Zadok |
6 | * Copyright (C) 2001-2003 Stony Brook University |
7 | * Copyright (C) 2004-2006 International Business Machines Corp. |
8 | * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
9 | * Michael C. Thompson <mcthomps@us.ibm.com> |
10 | */ |
11 | |
12 | #include <linux/fs.h> |
13 | #include <linux/mount.h> |
14 | #include <linux/key.h> |
15 | #include <linux/slab.h> |
16 | #include <linux/seq_file.h> |
17 | #include <linux/file.h> |
18 | #include <linux/statfs.h> |
19 | #include <linux/magic.h> |
20 | #include "ecryptfs_kernel.h" |
21 | |
22 | struct kmem_cache *ecryptfs_inode_info_cache; |
23 | |
24 | /** |
25 | * ecryptfs_alloc_inode - allocate an ecryptfs inode |
26 | * @sb: Pointer to the ecryptfs super block |
27 | * |
28 | * Called to bring an inode into existence. |
29 | * |
30 | * Only handle allocation, setting up structures should be done in |
31 | * ecryptfs_read_inode. This is because the kernel, between now and |
32 | * then, will 0 out the private data pointer. |
33 | * |
34 | * Returns a pointer to a newly allocated inode, NULL otherwise |
35 | */ |
36 | static struct inode *ecryptfs_alloc_inode(struct super_block *sb) |
37 | { |
38 | struct ecryptfs_inode_info *inode_info; |
39 | struct inode *inode = NULL; |
40 | |
41 | inode_info = alloc_inode_sb(sb, cache: ecryptfs_inode_info_cache, GFP_KERNEL); |
42 | if (unlikely(!inode_info)) |
43 | goto out; |
44 | if (ecryptfs_init_crypt_stat(crypt_stat: &inode_info->crypt_stat)) { |
45 | kmem_cache_free(s: ecryptfs_inode_info_cache, objp: inode_info); |
46 | goto out; |
47 | } |
48 | mutex_init(&inode_info->lower_file_mutex); |
49 | atomic_set(v: &inode_info->lower_file_count, i: 0); |
50 | inode_info->lower_file = NULL; |
51 | inode = &inode_info->vfs_inode; |
52 | out: |
53 | return inode; |
54 | } |
55 | |
56 | static void ecryptfs_free_inode(struct inode *inode) |
57 | { |
58 | struct ecryptfs_inode_info *inode_info; |
59 | inode_info = ecryptfs_inode_to_private(inode); |
60 | |
61 | kmem_cache_free(s: ecryptfs_inode_info_cache, objp: inode_info); |
62 | } |
63 | |
64 | /** |
65 | * ecryptfs_destroy_inode |
66 | * @inode: The ecryptfs inode |
67 | * |
68 | * This is used during the final destruction of the inode. All |
69 | * allocation of memory related to the inode, including allocated |
70 | * memory in the crypt_stat struct, will be released here. |
71 | * There should be no chance that this deallocation will be missed. |
72 | */ |
73 | static void ecryptfs_destroy_inode(struct inode *inode) |
74 | { |
75 | struct ecryptfs_inode_info *inode_info; |
76 | |
77 | inode_info = ecryptfs_inode_to_private(inode); |
78 | BUG_ON(inode_info->lower_file); |
79 | ecryptfs_destroy_crypt_stat(crypt_stat: &inode_info->crypt_stat); |
80 | } |
81 | |
82 | /** |
83 | * ecryptfs_statfs |
84 | * @dentry: The ecryptfs dentry |
85 | * @buf: The struct kstatfs to fill in with stats |
86 | * |
87 | * Get the filesystem statistics. Currently, we let this pass right through |
88 | * to the lower filesystem and take no action ourselves. |
89 | */ |
90 | static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf) |
91 | { |
92 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); |
93 | int rc; |
94 | |
95 | if (!lower_dentry->d_sb->s_op->statfs) |
96 | return -ENOSYS; |
97 | |
98 | rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf); |
99 | if (rc) |
100 | return rc; |
101 | |
102 | buf->f_type = ECRYPTFS_SUPER_MAGIC; |
103 | rc = ecryptfs_set_f_namelen(namelen: &buf->f_namelen, lower_namelen: buf->f_namelen, |
104 | mount_crypt_stat: &ecryptfs_superblock_to_private(sb: dentry->d_sb)->mount_crypt_stat); |
105 | |
106 | return rc; |
107 | } |
108 | |
109 | /** |
110 | * ecryptfs_evict_inode |
111 | * @inode: The ecryptfs inode |
112 | * |
113 | * Called by iput() when the inode reference count reached zero |
114 | * and the inode is not hashed anywhere. Used to clear anything |
115 | * that needs to be, before the inode is completely destroyed and put |
116 | * on the inode free list. We use this to drop out reference to the |
117 | * lower inode. |
118 | */ |
119 | static void ecryptfs_evict_inode(struct inode *inode) |
120 | { |
121 | truncate_inode_pages_final(&inode->i_data); |
122 | clear_inode(inode); |
123 | iput(ecryptfs_inode_to_lower(inode)); |
124 | } |
125 | |
126 | /* |
127 | * ecryptfs_show_options |
128 | * |
129 | * Prints the mount options for a given superblock. |
130 | * Returns zero; does not fail. |
131 | */ |
132 | static int ecryptfs_show_options(struct seq_file *m, struct dentry *root) |
133 | { |
134 | struct super_block *sb = root->d_sb; |
135 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
136 | &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; |
137 | struct ecryptfs_global_auth_tok *walker; |
138 | |
139 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
140 | list_for_each_entry(walker, |
141 | &mount_crypt_stat->global_auth_tok_list, |
142 | mount_crypt_stat_list) { |
143 | if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK) |
144 | seq_printf(m, fmt: ",ecryptfs_fnek_sig=%s" , walker->sig); |
145 | else |
146 | seq_printf(m, fmt: ",ecryptfs_sig=%s" , walker->sig); |
147 | } |
148 | mutex_unlock(lock: &mount_crypt_stat->global_auth_tok_list_mutex); |
149 | |
150 | seq_printf(m, fmt: ",ecryptfs_cipher=%s" , |
151 | mount_crypt_stat->global_default_cipher_name); |
152 | |
153 | if (mount_crypt_stat->global_default_cipher_key_size) |
154 | seq_printf(m, fmt: ",ecryptfs_key_bytes=%zd" , |
155 | mount_crypt_stat->global_default_cipher_key_size); |
156 | if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) |
157 | seq_printf(m, fmt: ",ecryptfs_passthrough" ); |
158 | if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) |
159 | seq_printf(m, fmt: ",ecryptfs_xattr_metadata" ); |
160 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) |
161 | seq_printf(m, fmt: ",ecryptfs_encrypted_view" ); |
162 | if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS) |
163 | seq_printf(m, fmt: ",ecryptfs_unlink_sigs" ); |
164 | if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) |
165 | seq_printf(m, fmt: ",ecryptfs_mount_auth_tok_only" ); |
166 | |
167 | return 0; |
168 | } |
169 | |
170 | const struct super_operations ecryptfs_sops = { |
171 | .alloc_inode = ecryptfs_alloc_inode, |
172 | .destroy_inode = ecryptfs_destroy_inode, |
173 | .free_inode = ecryptfs_free_inode, |
174 | .statfs = ecryptfs_statfs, |
175 | .remount_fs = NULL, |
176 | .evict_inode = ecryptfs_evict_inode, |
177 | .show_options = ecryptfs_show_options |
178 | }; |
179 | |