Commit | Line | Data |
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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> |
5329aa51 | 11 | #include <linux/fs_parser.h> |
d68772b7 MF |
12 | #include <linux/module.h> |
13 | #include <linux/pagemap.h> | |
a614e192 | 14 | #include <linux/ucs2_string.h> |
20b4fb48 LT |
15 | #include <linux/slab.h> |
16 | #include <linux/magic.h> | |
d86ff333 | 17 | #include <linux/statfs.h> |
94f7f618 | 18 | #include <linux/notifier.h> |
0e8d2444 | 19 | #include <linux/printk.h> |
d68772b7 MF |
20 | |
21 | #include "internal.h" | |
22 | ||
94f7f618 MK |
23 | static int efivarfs_ops_notifier(struct notifier_block *nb, unsigned long event, |
24 | void *data) | |
25 | { | |
26 | struct efivarfs_fs_info *sfi = container_of(nb, struct efivarfs_fs_info, nb); | |
27 | ||
28 | switch (event) { | |
29 | case EFIVAR_OPS_RDONLY: | |
30 | sfi->sb->s_flags |= SB_RDONLY; | |
31 | break; | |
32 | case EFIVAR_OPS_RDWR: | |
33 | sfi->sb->s_flags &= ~SB_RDONLY; | |
34 | break; | |
35 | default: | |
36 | return NOTIFY_DONE; | |
37 | } | |
38 | ||
39 | return NOTIFY_OK; | |
40 | } | |
41 | ||
d68772b7 MF |
42 | static void efivarfs_evict_inode(struct inode *inode) |
43 | { | |
44 | clear_inode(inode); | |
45 | } | |
46 | ||
5329aa51 JZ |
47 | static int efivarfs_show_options(struct seq_file *m, struct dentry *root) |
48 | { | |
49 | struct super_block *sb = root->d_sb; | |
50 | struct efivarfs_fs_info *sbi = sb->s_fs_info; | |
51 | struct efivarfs_mount_opts *opts = &sbi->mount_opts; | |
52 | ||
53 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) | |
54 | seq_printf(m, ",uid=%u", | |
55 | from_kuid_munged(&init_user_ns, opts->uid)); | |
56 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
57 | seq_printf(m, ",gid=%u", | |
58 | from_kgid_munged(&init_user_ns, opts->gid)); | |
59 | return 0; | |
60 | } | |
61 | ||
d86ff333 AA |
62 | static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf) |
63 | { | |
64 | const u32 attr = EFI_VARIABLE_NON_VOLATILE | | |
65 | EFI_VARIABLE_BOOTSERVICE_ACCESS | | |
66 | EFI_VARIABLE_RUNTIME_ACCESS; | |
67 | u64 storage_space, remaining_space, max_variable_size; | |
ae62bcb5 | 68 | u64 id = huge_encode_dev(dentry->d_sb->s_dev); |
d86ff333 AA |
69 | efi_status_t status; |
70 | ||
79b83606 HS |
71 | /* Some UEFI firmware does not implement QueryVariableInfo() */ |
72 | storage_space = remaining_space = 0; | |
73 | if (efi_rt_services_supported(EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO)) { | |
74 | status = efivar_query_variable_info(attr, &storage_space, | |
75 | &remaining_space, | |
76 | &max_variable_size); | |
77 | if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) | |
78 | pr_warn_ratelimited("query_variable_info() failed: 0x%lx\n", | |
79 | status); | |
80 | } | |
d86ff333 AA |
81 | |
82 | /* | |
83 | * This is not a normal filesystem, so no point in pretending it has a block | |
84 | * size; we declare f_bsize to 1, so that we can then report the exact value | |
85 | * sent by EFI QueryVariableInfo in f_blocks and f_bfree | |
86 | */ | |
87 | buf->f_bsize = 1; | |
88 | buf->f_namelen = NAME_MAX; | |
89 | buf->f_blocks = storage_space; | |
90 | buf->f_bfree = remaining_space; | |
91 | buf->f_type = dentry->d_sb->s_magic; | |
ae62bcb5 | 92 | buf->f_fsid = u64_to_fsid(id); |
d86ff333 AA |
93 | |
94 | /* | |
95 | * In f_bavail we declare the free space that the kernel will allow writing | |
96 | * when the storage_paranoia x86 quirk is active. To use more, users | |
97 | * should boot the kernel with efi_no_storage_paranoia. | |
98 | */ | |
99 | if (remaining_space > efivar_reserved_space()) | |
100 | buf->f_bavail = remaining_space - efivar_reserved_space(); | |
101 | else | |
102 | buf->f_bavail = 0; | |
103 | ||
104 | return 0; | |
105 | } | |
d68772b7 | 106 | static const struct super_operations efivarfs_ops = { |
d86ff333 | 107 | .statfs = efivarfs_statfs, |
d68772b7 MF |
108 | .drop_inode = generic_delete_inode, |
109 | .evict_inode = efivarfs_evict_inode, | |
5329aa51 | 110 | .show_options = efivarfs_show_options, |
d68772b7 MF |
111 | }; |
112 | ||
d68772b7 MF |
113 | /* |
114 | * Compare two efivarfs file names. | |
115 | * | |
116 | * An efivarfs filename is composed of two parts, | |
117 | * | |
118 | * 1. A case-sensitive variable name | |
119 | * 2. A case-insensitive GUID | |
120 | * | |
121 | * So we need to perform a case-sensitive match on part 1 and a | |
122 | * case-insensitive match on part 2. | |
123 | */ | |
6fa67e70 | 124 | static int efivarfs_d_compare(const struct dentry *dentry, |
d68772b7 MF |
125 | unsigned int len, const char *str, |
126 | const struct qstr *name) | |
127 | { | |
128 | int guid = len - EFI_VARIABLE_GUID_LEN; | |
129 | ||
130 | if (name->len != len) | |
131 | return 1; | |
132 | ||
133 | /* Case-sensitive compare for the variable name */ | |
134 | if (memcmp(str, name->name, guid)) | |
135 | return 1; | |
136 | ||
137 | /* Case-insensitive compare for the GUID */ | |
138 | return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN); | |
139 | } | |
140 | ||
da53be12 | 141 | static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr) |
d68772b7 | 142 | { |
8387ff25 | 143 | unsigned long hash = init_name_hash(dentry); |
d68772b7 MF |
144 | const unsigned char *s = qstr->name; |
145 | unsigned int len = qstr->len; | |
146 | ||
147 | if (!efivarfs_valid_name(s, len)) | |
148 | return -EINVAL; | |
149 | ||
150 | while (len-- > EFI_VARIABLE_GUID_LEN) | |
151 | hash = partial_name_hash(*s++, hash); | |
152 | ||
153 | /* GUID is case-insensitive. */ | |
154 | while (len--) | |
155 | hash = partial_name_hash(tolower(*s++), hash); | |
156 | ||
157 | qstr->hash = end_name_hash(hash); | |
158 | return 0; | |
159 | } | |
160 | ||
e37dcbfb | 161 | static const struct dentry_operations efivarfs_d_ops = { |
d68772b7 MF |
162 | .d_compare = efivarfs_d_compare, |
163 | .d_hash = efivarfs_d_hash, | |
b26d4cd3 | 164 | .d_delete = always_delete_dentry, |
d68772b7 MF |
165 | }; |
166 | ||
167 | static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name) | |
168 | { | |
169 | struct dentry *d; | |
170 | struct qstr q; | |
171 | int err; | |
172 | ||
173 | q.name = name; | |
174 | q.len = strlen(name); | |
175 | ||
8387ff25 | 176 | err = efivarfs_d_hash(parent, &q); |
d68772b7 MF |
177 | if (err) |
178 | return ERR_PTR(err); | |
179 | ||
180 | d = d_alloc(parent, &q); | |
181 | if (d) | |
182 | return d; | |
183 | ||
184 | return ERR_PTR(-ENOMEM); | |
185 | } | |
186 | ||
187 | static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor, | |
cdb46a8a AB |
188 | unsigned long name_size, void *data, |
189 | struct list_head *list) | |
d68772b7 MF |
190 | { |
191 | struct super_block *sb = (struct super_block *)data; | |
192 | struct efivar_entry *entry; | |
193 | struct inode *inode = NULL; | |
194 | struct dentry *dentry, *root = sb->s_root; | |
195 | unsigned long size = 0; | |
196 | char *name; | |
e0d64e6a | 197 | int len; |
d68772b7 | 198 | int err = -ENOMEM; |
ed8b0de5 | 199 | bool is_removable = false; |
d68772b7 | 200 | |
63ffb573 JD |
201 | if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) |
202 | return 0; | |
203 | ||
c57dcb56 | 204 | entry = kzalloc(sizeof(*entry), GFP_KERNEL); |
d68772b7 MF |
205 | if (!entry) |
206 | return err; | |
207 | ||
208 | memcpy(entry->var.VariableName, name16, name_size); | |
209 | memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t)); | |
210 | ||
e0d64e6a | 211 | len = ucs2_utf8size(entry->var.VariableName); |
d68772b7 MF |
212 | |
213 | /* name, plus '-', plus GUID, plus NUL*/ | |
214 | name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL); | |
215 | if (!name) | |
216 | goto fail; | |
217 | ||
e0d64e6a | 218 | ucs2_as_utf8(name, entry->var.VariableName, len); |
d68772b7 | 219 | |
ed8b0de5 PJ |
220 | if (efivar_variable_is_removable(entry->var.VendorGuid, name, len)) |
221 | is_removable = true; | |
222 | ||
d68772b7 MF |
223 | name[len] = '-'; |
224 | ||
26e02272 | 225 | efi_guid_to_str(&entry->var.VendorGuid, name + len + 1); |
d68772b7 MF |
226 | |
227 | name[len + EFI_VARIABLE_GUID_LEN+1] = '\0'; | |
228 | ||
336af6a4 MS |
229 | /* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */ |
230 | strreplace(name, '/', '!'); | |
231 | ||
ed8b0de5 PJ |
232 | inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0, |
233 | is_removable); | |
d68772b7 MF |
234 | if (!inode) |
235 | goto fail_name; | |
236 | ||
237 | dentry = efivarfs_alloc_dentry(root, name); | |
238 | if (IS_ERR(dentry)) { | |
239 | err = PTR_ERR(dentry); | |
240 | goto fail_inode; | |
241 | } | |
242 | ||
ec3507b2 | 243 | __efivar_entry_get(entry, NULL, &size, NULL); |
cdb46a8a | 244 | __efivar_entry_add(entry, list); |
d68772b7 | 245 | |
22c2b77f MF |
246 | /* copied by the above to local storage in the dentry. */ |
247 | kfree(name); | |
248 | ||
5955102c | 249 | inode_lock(inode); |
d68772b7 MF |
250 | inode->i_private = entry; |
251 | i_size_write(inode, size + sizeof(entry->var.Attributes)); | |
5955102c | 252 | inode_unlock(inode); |
d68772b7 MF |
253 | d_add(dentry, inode); |
254 | ||
255 | return 0; | |
256 | ||
257 | fail_inode: | |
258 | iput(inode); | |
259 | fail_name: | |
260 | kfree(name); | |
261 | fail: | |
262 | kfree(entry); | |
263 | return err; | |
264 | } | |
265 | ||
266 | static int efivarfs_destroy(struct efivar_entry *entry, void *data) | |
267 | { | |
3a75f9f2 | 268 | efivar_entry_remove(entry); |
d68772b7 MF |
269 | kfree(entry); |
270 | return 0; | |
271 | } | |
272 | ||
5329aa51 JZ |
273 | enum { |
274 | Opt_uid, Opt_gid, | |
275 | }; | |
276 | ||
277 | static const struct fs_parameter_spec efivarfs_parameters[] = { | |
278 | fsparam_u32("uid", Opt_uid), | |
279 | fsparam_u32("gid", Opt_gid), | |
280 | {}, | |
281 | }; | |
282 | ||
283 | static int efivarfs_parse_param(struct fs_context *fc, struct fs_parameter *param) | |
284 | { | |
285 | struct efivarfs_fs_info *sbi = fc->s_fs_info; | |
286 | struct efivarfs_mount_opts *opts = &sbi->mount_opts; | |
287 | struct fs_parse_result result; | |
288 | int opt; | |
289 | ||
290 | opt = fs_parse(fc, efivarfs_parameters, param, &result); | |
291 | if (opt < 0) | |
292 | return opt; | |
293 | ||
294 | switch (opt) { | |
295 | case Opt_uid: | |
296 | opts->uid = make_kuid(current_user_ns(), result.uint_32); | |
297 | if (!uid_valid(opts->uid)) | |
298 | return -EINVAL; | |
299 | break; | |
300 | case Opt_gid: | |
301 | opts->gid = make_kgid(current_user_ns(), result.uint_32); | |
302 | if (!gid_valid(opts->gid)) | |
303 | return -EINVAL; | |
304 | break; | |
305 | default: | |
306 | return -EINVAL; | |
307 | } | |
308 | ||
309 | return 0; | |
310 | } | |
311 | ||
47999745 | 312 | static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc) |
d68772b7 | 313 | { |
cdb46a8a | 314 | struct efivarfs_fs_info *sfi = sb->s_fs_info; |
d68772b7 MF |
315 | struct inode *inode = NULL; |
316 | struct dentry *root; | |
317 | int err; | |
318 | ||
d68772b7 | 319 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
09cbfeaf KS |
320 | sb->s_blocksize = PAGE_SIZE; |
321 | sb->s_blocksize_bits = PAGE_SHIFT; | |
d68772b7 MF |
322 | sb->s_magic = EFIVARFS_MAGIC; |
323 | sb->s_op = &efivarfs_ops; | |
324 | sb->s_d_op = &efivarfs_d_ops; | |
325 | sb->s_time_gran = 1; | |
326 | ||
f88814cc AB |
327 | if (!efivar_supports_writes()) |
328 | sb->s_flags |= SB_RDONLY; | |
329 | ||
ed8b0de5 | 330 | inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true); |
d68772b7 MF |
331 | if (!inode) |
332 | return -ENOMEM; | |
333 | inode->i_op = &efivarfs_dir_inode_operations; | |
334 | ||
335 | root = d_make_root(inode); | |
336 | sb->s_root = root; | |
337 | if (!root) | |
338 | return -ENOMEM; | |
339 | ||
94f7f618 MK |
340 | sfi->sb = sb; |
341 | sfi->nb.notifier_call = efivarfs_ops_notifier; | |
342 | err = blocking_notifier_chain_register(&efivar_ops_nh, &sfi->nb); | |
343 | if (err) | |
344 | return err; | |
345 | ||
9ca01c7a | 346 | return efivar_init(efivarfs_callback, sb, true, &sfi->efivarfs_list); |
d68772b7 MF |
347 | } |
348 | ||
47999745 DH |
349 | static int efivarfs_get_tree(struct fs_context *fc) |
350 | { | |
351 | return get_tree_single(fc, efivarfs_fill_super); | |
352 | } | |
353 | ||
0e8d2444 IA |
354 | static int efivarfs_reconfigure(struct fs_context *fc) |
355 | { | |
356 | if (!efivar_supports_writes() && !(fc->sb_flags & SB_RDONLY)) { | |
357 | pr_err("Firmware does not support SetVariableRT. Can not remount with rw\n"); | |
358 | return -EINVAL; | |
359 | } | |
360 | ||
361 | return 0; | |
362 | } | |
363 | ||
47999745 DH |
364 | static const struct fs_context_operations efivarfs_context_ops = { |
365 | .get_tree = efivarfs_get_tree, | |
5329aa51 | 366 | .parse_param = efivarfs_parse_param, |
0e8d2444 | 367 | .reconfigure = efivarfs_reconfigure, |
47999745 DH |
368 | }; |
369 | ||
370 | static int efivarfs_init_fs_context(struct fs_context *fc) | |
d68772b7 | 371 | { |
5329aa51 JZ |
372 | struct efivarfs_fs_info *sfi; |
373 | ||
d28076dd AB |
374 | if (!efivar_is_available()) |
375 | return -EOPNOTSUPP; | |
376 | ||
5329aa51 JZ |
377 | sfi = kzalloc(sizeof(*sfi), GFP_KERNEL); |
378 | if (!sfi) | |
379 | return -ENOMEM; | |
380 | ||
cdb46a8a AB |
381 | INIT_LIST_HEAD(&sfi->efivarfs_list); |
382 | ||
5329aa51 JZ |
383 | sfi->mount_opts.uid = GLOBAL_ROOT_UID; |
384 | sfi->mount_opts.gid = GLOBAL_ROOT_GID; | |
385 | ||
386 | fc->s_fs_info = sfi; | |
47999745 DH |
387 | fc->ops = &efivarfs_context_ops; |
388 | return 0; | |
d68772b7 MF |
389 | } |
390 | ||
391 | static void efivarfs_kill_sb(struct super_block *sb) | |
392 | { | |
547713d5 AB |
393 | struct efivarfs_fs_info *sfi = sb->s_fs_info; |
394 | ||
94f7f618 | 395 | blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb); |
d68772b7 | 396 | kill_litter_super(sb); |
d68772b7 MF |
397 | |
398 | /* Remove all entries and destroy */ | |
cdb46a8a | 399 | efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL); |
547713d5 | 400 | kfree(sfi); |
d68772b7 MF |
401 | } |
402 | ||
403 | static struct file_system_type efivarfs_type = { | |
af5a29ae | 404 | .owner = THIS_MODULE, |
d68772b7 | 405 | .name = "efivarfs", |
47999745 | 406 | .init_fs_context = efivarfs_init_fs_context, |
d68772b7 | 407 | .kill_sb = efivarfs_kill_sb, |
5329aa51 | 408 | .parameters = efivarfs_parameters, |
d68772b7 MF |
409 | }; |
410 | ||
411 | static __init int efivarfs_init(void) | |
412 | { | |
d68772b7 MF |
413 | return register_filesystem(&efivarfs_type); |
414 | } | |
415 | ||
af5a29ae MK |
416 | static __exit void efivarfs_exit(void) |
417 | { | |
418 | unregister_filesystem(&efivarfs_type); | |
419 | } | |
420 | ||
d68772b7 MF |
421 | MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr"); |
422 | MODULE_DESCRIPTION("EFI Variable Filesystem"); | |
423 | MODULE_LICENSE("GPL"); | |
424 | MODULE_ALIAS_FS("efivarfs"); | |
425 | ||
426 | module_init(efivarfs_init); | |
af5a29ae | 427 | module_exit(efivarfs_exit); |