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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
d68772b7 MF |
2 | /* |
3 | * Copyright (C) 2012 Red Hat, Inc. | |
4 | * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> | |
d68772b7 MF |
5 | */ |
6 | ||
7 | #include <linux/ctype.h> | |
8 | #include <linux/efi.h> | |
9 | #include <linux/fs.h> | |
47999745 | 10 | #include <linux/fs_context.h> |
d68772b7 MF |
11 | #include <linux/module.h> |
12 | #include <linux/pagemap.h> | |
a614e192 | 13 | #include <linux/ucs2_string.h> |
20b4fb48 LT |
14 | #include <linux/slab.h> |
15 | #include <linux/magic.h> | |
d68772b7 MF |
16 | |
17 | #include "internal.h" | |
18 | ||
19 | LIST_HEAD(efivarfs_list); | |
20 | ||
21 | static void efivarfs_evict_inode(struct inode *inode) | |
22 | { | |
23 | clear_inode(inode); | |
24 | } | |
25 | ||
26 | static const struct super_operations efivarfs_ops = { | |
27 | .statfs = simple_statfs, | |
28 | .drop_inode = generic_delete_inode, | |
29 | .evict_inode = efivarfs_evict_inode, | |
d68772b7 MF |
30 | }; |
31 | ||
d68772b7 MF |
32 | /* |
33 | * Compare two efivarfs file names. | |
34 | * | |
35 | * An efivarfs filename is composed of two parts, | |
36 | * | |
37 | * 1. A case-sensitive variable name | |
38 | * 2. A case-insensitive GUID | |
39 | * | |
40 | * So we need to perform a case-sensitive match on part 1 and a | |
41 | * case-insensitive match on part 2. | |
42 | */ | |
6fa67e70 | 43 | static int efivarfs_d_compare(const struct dentry *dentry, |
d68772b7 MF |
44 | unsigned int len, const char *str, |
45 | const struct qstr *name) | |
46 | { | |
47 | int guid = len - EFI_VARIABLE_GUID_LEN; | |
48 | ||
49 | if (name->len != len) | |
50 | return 1; | |
51 | ||
52 | /* Case-sensitive compare for the variable name */ | |
53 | if (memcmp(str, name->name, guid)) | |
54 | return 1; | |
55 | ||
56 | /* Case-insensitive compare for the GUID */ | |
57 | return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN); | |
58 | } | |
59 | ||
da53be12 | 60 | static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr) |
d68772b7 | 61 | { |
8387ff25 | 62 | unsigned long hash = init_name_hash(dentry); |
d68772b7 MF |
63 | const unsigned char *s = qstr->name; |
64 | unsigned int len = qstr->len; | |
65 | ||
66 | if (!efivarfs_valid_name(s, len)) | |
67 | return -EINVAL; | |
68 | ||
69 | while (len-- > EFI_VARIABLE_GUID_LEN) | |
70 | hash = partial_name_hash(*s++, hash); | |
71 | ||
72 | /* GUID is case-insensitive. */ | |
73 | while (len--) | |
74 | hash = partial_name_hash(tolower(*s++), hash); | |
75 | ||
76 | qstr->hash = end_name_hash(hash); | |
77 | return 0; | |
78 | } | |
79 | ||
e37dcbfb | 80 | static const struct dentry_operations efivarfs_d_ops = { |
d68772b7 MF |
81 | .d_compare = efivarfs_d_compare, |
82 | .d_hash = efivarfs_d_hash, | |
b26d4cd3 | 83 | .d_delete = always_delete_dentry, |
d68772b7 MF |
84 | }; |
85 | ||
86 | static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name) | |
87 | { | |
88 | struct dentry *d; | |
89 | struct qstr q; | |
90 | int err; | |
91 | ||
92 | q.name = name; | |
93 | q.len = strlen(name); | |
94 | ||
8387ff25 | 95 | err = efivarfs_d_hash(parent, &q); |
d68772b7 MF |
96 | if (err) |
97 | return ERR_PTR(err); | |
98 | ||
99 | d = d_alloc(parent, &q); | |
100 | if (d) | |
101 | return d; | |
102 | ||
103 | return ERR_PTR(-ENOMEM); | |
104 | } | |
105 | ||
106 | static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor, | |
107 | unsigned long name_size, void *data) | |
108 | { | |
109 | struct super_block *sb = (struct super_block *)data; | |
110 | struct efivar_entry *entry; | |
111 | struct inode *inode = NULL; | |
112 | struct dentry *dentry, *root = sb->s_root; | |
113 | unsigned long size = 0; | |
114 | char *name; | |
e0d64e6a | 115 | int len; |
d68772b7 | 116 | int err = -ENOMEM; |
ed8b0de5 | 117 | bool is_removable = false; |
d68772b7 | 118 | |
63ffb573 JD |
119 | if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) |
120 | return 0; | |
121 | ||
c57dcb56 | 122 | entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
d68772b7 MF |
123 | if (!entry) |
124 | return err; | |
125 | ||
126 | memcpy(entry->var.VariableName, name16, name_size); | |
127 | memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t)); | |
128 | ||
e0d64e6a | 129 | len = ucs2_utf8size(entry->var.VariableName); |
d68772b7 MF |
130 | |
131 | /* name, plus '-', plus GUID, plus NUL*/ | |
132 | name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL); | |
133 | if (!name) | |
134 | goto fail; | |
135 | ||
e0d64e6a | 136 | ucs2_as_utf8(name, entry->var.VariableName, len); |
d68772b7 | 137 | |
ed8b0de5 PJ |
138 | if (efivar_variable_is_removable(entry->var.VendorGuid, name, len)) |
139 | is_removable = true; | |
140 | ||
d68772b7 MF |
141 | name[len] = '-'; |
142 | ||
26e02272 | 143 | efi_guid_to_str(&entry->var.VendorGuid, name + len + 1); |
d68772b7 MF |
144 | |
145 | name[len + EFI_VARIABLE_GUID_LEN+1] = '\0'; | |
146 | ||
336af6a4 MS |
147 | /* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */ |
148 | strreplace(name, '/', '!'); | |
149 | ||
ed8b0de5 PJ |
150 | inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0, |
151 | is_removable); | |
d68772b7 MF |
152 | if (!inode) |
153 | goto fail_name; | |
154 | ||
155 | dentry = efivarfs_alloc_dentry(root, name); | |
156 | if (IS_ERR(dentry)) { | |
157 | err = PTR_ERR(dentry); | |
158 | goto fail_inode; | |
159 | } | |
160 | ||
ec3507b2 AB |
161 | __efivar_entry_get(entry, NULL, &size, NULL); |
162 | __efivar_entry_add(entry, &efivarfs_list); | |
d68772b7 | 163 | |
22c2b77f MF |
164 | /* copied by the above to local storage in the dentry. */ |
165 | kfree(name); | |
166 | ||
5955102c | 167 | inode_lock(inode); |
d68772b7 MF |
168 | inode->i_private = entry; |
169 | i_size_write(inode, size + sizeof(entry->var.Attributes)); | |
5955102c | 170 | inode_unlock(inode); |
d68772b7 MF |
171 | d_add(dentry, inode); |
172 | ||
173 | return 0; | |
174 | ||
175 | fail_inode: | |
176 | iput(inode); | |
177 | fail_name: | |
178 | kfree(name); | |
179 | fail: | |
180 | kfree(entry); | |
181 | return err; | |
182 | } | |
183 | ||
184 | static int efivarfs_destroy(struct efivar_entry *entry, void *data) | |
185 | { | |
3a75f9f2 | 186 | efivar_entry_remove(entry); |
d68772b7 MF |
187 | kfree(entry); |
188 | return 0; | |
189 | } | |
190 | ||
47999745 | 191 | static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc) |
d68772b7 MF |
192 | { |
193 | struct inode *inode = NULL; | |
194 | struct dentry *root; | |
195 | int err; | |
196 | ||
301de9a2 JH |
197 | if (!efivar_is_available()) |
198 | return -EOPNOTSUPP; | |
199 | ||
d68772b7 | 200 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
09cbfeaf KS |
201 | sb->s_blocksize = PAGE_SIZE; |
202 | sb->s_blocksize_bits = PAGE_SHIFT; | |
d68772b7 MF |
203 | sb->s_magic = EFIVARFS_MAGIC; |
204 | sb->s_op = &efivarfs_ops; | |
205 | sb->s_d_op = &efivarfs_d_ops; | |
206 | sb->s_time_gran = 1; | |
207 | ||
f88814cc AB |
208 | if (!efivar_supports_writes()) |
209 | sb->s_flags |= SB_RDONLY; | |
210 | ||
ed8b0de5 | 211 | inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true); |
d68772b7 MF |
212 | if (!inode) |
213 | return -ENOMEM; | |
214 | inode->i_op = &efivarfs_dir_inode_operations; | |
215 | ||
216 | root = d_make_root(inode); | |
217 | sb->s_root = root; | |
218 | if (!root) | |
219 | return -ENOMEM; | |
220 | ||
221 | INIT_LIST_HEAD(&efivarfs_list); | |
222 | ||
1cfd6316 | 223 | err = efivar_init(efivarfs_callback, (void *)sb, true, &efivarfs_list); |
d68772b7 | 224 | if (err) |
3a75f9f2 | 225 | efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL); |
d68772b7 MF |
226 | |
227 | return err; | |
228 | } | |
229 | ||
47999745 DH |
230 | static int efivarfs_get_tree(struct fs_context *fc) |
231 | { | |
232 | return get_tree_single(fc, efivarfs_fill_super); | |
233 | } | |
234 | ||
235 | static const struct fs_context_operations efivarfs_context_ops = { | |
236 | .get_tree = efivarfs_get_tree, | |
237 | }; | |
238 | ||
239 | static int efivarfs_init_fs_context(struct fs_context *fc) | |
d68772b7 | 240 | { |
47999745 DH |
241 | fc->ops = &efivarfs_context_ops; |
242 | return 0; | |
d68772b7 MF |
243 | } |
244 | ||
245 | static void efivarfs_kill_sb(struct super_block *sb) | |
246 | { | |
247 | kill_litter_super(sb); | |
d68772b7 | 248 | |
301de9a2 JH |
249 | if (!efivar_is_available()) |
250 | return; | |
251 | ||
d68772b7 | 252 | /* Remove all entries and destroy */ |
3a75f9f2 | 253 | efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL); |
d68772b7 MF |
254 | } |
255 | ||
256 | static struct file_system_type efivarfs_type = { | |
af5a29ae | 257 | .owner = THIS_MODULE, |
d68772b7 | 258 | .name = "efivarfs", |
47999745 | 259 | .init_fs_context = efivarfs_init_fs_context, |
d68772b7 MF |
260 | .kill_sb = efivarfs_kill_sb, |
261 | }; | |
262 | ||
263 | static __init int efivarfs_init(void) | |
264 | { | |
d68772b7 MF |
265 | return register_filesystem(&efivarfs_type); |
266 | } | |
267 | ||
af5a29ae MK |
268 | static __exit void efivarfs_exit(void) |
269 | { | |
270 | unregister_filesystem(&efivarfs_type); | |
271 | } | |
272 | ||
d68772b7 MF |
273 | MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr"); |
274 | MODULE_DESCRIPTION("EFI Variable Filesystem"); | |
275 | MODULE_LICENSE("GPL"); | |
276 | MODULE_ALIAS_FS("efivarfs"); | |
277 | ||
278 | module_init(efivarfs_init); | |
af5a29ae | 279 | module_exit(efivarfs_exit); |