1
2
3
4
5
6
7
8
9
10
11
12#include <linux/efi.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/ucs2_string.h>
16#include <linux/compat.h>
17
18#define EFIVARS_VERSION "0.08"
19#define EFIVARS_DATE "2004-May-17"
20
21MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
22MODULE_DESCRIPTION("sysfs interface to EFI Variables");
23MODULE_LICENSE("GPL");
24MODULE_VERSION(EFIVARS_VERSION);
25
26static LIST_HEAD(efivar_sysfs_list);
27
28static struct kset *efivars_kset;
29
30static struct bin_attribute *efivars_new_var;
31static struct bin_attribute *efivars_del_var;
32
33struct compat_efi_variable {
34 efi_char16_t VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
35 efi_guid_t VendorGuid;
36 __u32 DataSize;
37 __u8 Data[1024];
38 __u32 Status;
39 __u32 Attributes;
40} __packed;
41
42struct efivar_attribute {
43 struct attribute attr;
44 ssize_t (*show) (struct efivar_entry *entry, char *buf);
45 ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count);
46};
47
48#define EFIVAR_ATTR(_name, _mode, _show, _store) \
49struct efivar_attribute efivar_attr_##_name = { \
50 .attr = {.name = __stringify(_name), .mode = _mode}, \
51 .show = _show, \
52 .store = _store, \
53};
54
55#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr)
56#define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj)
57
58
59
60
61static int
62efivar_create_sysfs_entry(struct efivar_entry *new_var);
63
64static ssize_t
65efivar_guid_read(struct efivar_entry *entry, char *buf)
66{
67 struct efi_variable *var = &entry->var;
68 char *str = buf;
69
70 if (!entry || !buf)
71 return 0;
72
73 efi_guid_to_str(&var->VendorGuid, str);
74 str += strlen(str);
75 str += sprintf(str, "\n");
76
77 return str - buf;
78}
79
80static ssize_t
81efivar_attr_read(struct efivar_entry *entry, char *buf)
82{
83 struct efi_variable *var = &entry->var;
84 unsigned long size = sizeof(var->Data);
85 char *str = buf;
86 int ret;
87
88 if (!entry || !buf)
89 return -EINVAL;
90
91 ret = efivar_entry_get(entry, &var->Attributes, &size, var->Data);
92 var->DataSize = size;
93 if (ret)
94 return -EIO;
95
96 if (var->Attributes & EFI_VARIABLE_NON_VOLATILE)
97 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n");
98 if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)
99 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n");
100 if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS)
101 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n");
102 if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD)
103 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n");
104 if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
105 str += sprintf(str,
106 "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n");
107 if (var->Attributes &
108 EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)
109 str += sprintf(str,
110 "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n");
111 if (var->Attributes & EFI_VARIABLE_APPEND_WRITE)
112 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n");
113 return str - buf;
114}
115
116static ssize_t
117efivar_size_read(struct efivar_entry *entry, char *buf)
118{
119 struct efi_variable *var = &entry->var;
120 unsigned long size = sizeof(var->Data);
121 char *str = buf;
122 int ret;
123
124 if (!entry || !buf)
125 return -EINVAL;
126
127 ret = efivar_entry_get(entry, &var->Attributes, &size, var->Data);
128 var->DataSize = size;
129 if (ret)
130 return -EIO;
131
132 str += sprintf(str, "0x%lx\n", var->DataSize);
133 return str - buf;
134}
135
136static ssize_t
137efivar_data_read(struct efivar_entry *entry, char *buf)
138{
139 struct efi_variable *var = &entry->var;
140 unsigned long size = sizeof(var->Data);
141 int ret;
142
143 if (!entry || !buf)
144 return -EINVAL;
145
146 ret = efivar_entry_get(entry, &var->Attributes, &size, var->Data);
147 var->DataSize = size;
148 if (ret)
149 return -EIO;
150
151 memcpy(buf, var->Data, var->DataSize);
152 return var->DataSize;
153}
154
155static inline int
156sanity_check(struct efi_variable *var, efi_char16_t *name, efi_guid_t vendor,
157 unsigned long size, u32 attributes, u8 *data)
158{
159
160
161
162
163 if (memcmp(name, var->VariableName, sizeof(var->VariableName)) ||
164 efi_guidcmp(vendor, var->VendorGuid)) {
165 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n");
166 return -EINVAL;
167 }
168
169 if ((size <= 0) || (attributes == 0)){
170 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n");
171 return -EINVAL;
172 }
173
174 if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
175 efivar_validate(vendor, name, data, size) == false) {
176 printk(KERN_ERR "efivars: Malformed variable content\n");
177 return -EINVAL;
178 }
179
180 return 0;
181}
182
183static void
184copy_out_compat(struct efi_variable *dst, struct compat_efi_variable *src)
185{
186 memcpy(dst->VariableName, src->VariableName, EFI_VAR_NAME_LEN);
187 memcpy(dst->Data, src->Data, sizeof(src->Data));
188
189 dst->VendorGuid = src->VendorGuid;
190 dst->DataSize = src->DataSize;
191 dst->Attributes = src->Attributes;
192}
193
194
195
196
197
198static ssize_t
199efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
200{
201 struct efi_variable *new_var, *var = &entry->var;
202 efi_char16_t *name;
203 unsigned long size;
204 efi_guid_t vendor;
205 u32 attributes;
206 u8 *data;
207 int err;
208
209 if (!entry || !buf)
210 return -EINVAL;
211
212 if (in_compat_syscall()) {
213 struct compat_efi_variable *compat;
214
215 if (count != sizeof(*compat))
216 return -EINVAL;
217
218 compat = (struct compat_efi_variable *)buf;
219 attributes = compat->Attributes;
220 vendor = compat->VendorGuid;
221 name = compat->VariableName;
222 size = compat->DataSize;
223 data = compat->Data;
224
225 err = sanity_check(var, name, vendor, size, attributes, data);
226 if (err)
227 return err;
228
229 copy_out_compat(&entry->var, compat);
230 } else {
231 if (count != sizeof(struct efi_variable))
232 return -EINVAL;
233
234 new_var = (struct efi_variable *)buf;
235
236 attributes = new_var->Attributes;
237 vendor = new_var->VendorGuid;
238 name = new_var->VariableName;
239 size = new_var->DataSize;
240 data = new_var->Data;
241
242 err = sanity_check(var, name, vendor, size, attributes, data);
243 if (err)
244 return err;
245
246 memcpy(&entry->var, new_var, count);
247 }
248
249 err = efivar_entry_set(entry, attributes, size, data, NULL);
250 if (err) {
251 printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err);
252 return -EIO;
253 }
254
255 return count;
256}
257
258static ssize_t
259efivar_show_raw(struct efivar_entry *entry, char *buf)
260{
261 struct efi_variable *var = &entry->var;
262 struct compat_efi_variable *compat;
263 unsigned long datasize = sizeof(var->Data);
264 size_t size;
265 int ret;
266
267 if (!entry || !buf)
268 return 0;
269
270 ret = efivar_entry_get(entry, &var->Attributes, &datasize, var->Data);
271 var->DataSize = datasize;
272 if (ret)
273 return -EIO;
274
275 if (in_compat_syscall()) {
276 compat = (struct compat_efi_variable *)buf;
277
278 size = sizeof(*compat);
279 memcpy(compat->VariableName, var->VariableName,
280 EFI_VAR_NAME_LEN);
281 memcpy(compat->Data, var->Data, sizeof(compat->Data));
282
283 compat->VendorGuid = var->VendorGuid;
284 compat->DataSize = var->DataSize;
285 compat->Attributes = var->Attributes;
286 } else {
287 size = sizeof(*var);
288 memcpy(buf, var, size);
289 }
290
291 return size;
292}
293
294
295
296
297
298static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr,
299 char *buf)
300{
301 struct efivar_entry *var = to_efivar_entry(kobj);
302 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
303 ssize_t ret = -EIO;
304
305 if (!capable(CAP_SYS_ADMIN))
306 return -EACCES;
307
308 if (efivar_attr->show) {
309 ret = efivar_attr->show(var, buf);
310 }
311 return ret;
312}
313
314static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr,
315 const char *buf, size_t count)
316{
317 struct efivar_entry *var = to_efivar_entry(kobj);
318 struct efivar_attribute *efivar_attr = to_efivar_attr(attr);
319 ssize_t ret = -EIO;
320
321 if (!capable(CAP_SYS_ADMIN))
322 return -EACCES;
323
324 if (efivar_attr->store)
325 ret = efivar_attr->store(var, buf, count);
326
327 return ret;
328}
329
330static const struct sysfs_ops efivar_attr_ops = {
331 .show = efivar_attr_show,
332 .store = efivar_attr_store,
333};
334
335static void efivar_release(struct kobject *kobj)
336{
337 struct efivar_entry *var = to_efivar_entry(kobj);
338 kfree(var);
339}
340
341static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
342static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
343static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
344static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
345static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
346
347static struct attribute *def_attrs[] = {
348 &efivar_attr_guid.attr,
349 &efivar_attr_size.attr,
350 &efivar_attr_attributes.attr,
351 &efivar_attr_data.attr,
352 &efivar_attr_raw_var.attr,
353 NULL,
354};
355
356static struct kobj_type efivar_ktype = {
357 .release = efivar_release,
358 .sysfs_ops = &efivar_attr_ops,
359 .default_attrs = def_attrs,
360};
361
362static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
363 struct bin_attribute *bin_attr,
364 char *buf, loff_t pos, size_t count)
365{
366 struct compat_efi_variable *compat = (struct compat_efi_variable *)buf;
367 struct efi_variable *new_var = (struct efi_variable *)buf;
368 struct efivar_entry *new_entry;
369 bool need_compat = in_compat_syscall();
370 efi_char16_t *name;
371 unsigned long size;
372 u32 attributes;
373 u8 *data;
374 int err;
375
376 if (!capable(CAP_SYS_ADMIN))
377 return -EACCES;
378
379 if (need_compat) {
380 if (count != sizeof(*compat))
381 return -EINVAL;
382
383 attributes = compat->Attributes;
384 name = compat->VariableName;
385 size = compat->DataSize;
386 data = compat->Data;
387 } else {
388 if (count != sizeof(*new_var))
389 return -EINVAL;
390
391 attributes = new_var->Attributes;
392 name = new_var->VariableName;
393 size = new_var->DataSize;
394 data = new_var->Data;
395 }
396
397 if ((attributes & ~EFI_VARIABLE_MASK) != 0 ||
398 efivar_validate(new_var->VendorGuid, name, data,
399 size) == false) {
400 printk(KERN_ERR "efivars: Malformed variable content\n");
401 return -EINVAL;
402 }
403
404 new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL);
405 if (!new_entry)
406 return -ENOMEM;
407
408 if (need_compat)
409 copy_out_compat(&new_entry->var, compat);
410 else
411 memcpy(&new_entry->var, new_var, sizeof(*new_var));
412
413 err = efivar_entry_set(new_entry, attributes, size,
414 data, &efivar_sysfs_list);
415 if (err) {
416 if (err == -EEXIST)
417 err = -EINVAL;
418 goto out;
419 }
420
421 if (efivar_create_sysfs_entry(new_entry)) {
422 printk(KERN_WARNING "efivars: failed to create sysfs entry.\n");
423 kfree(new_entry);
424 }
425 return count;
426
427out:
428 kfree(new_entry);
429 return err;
430}
431
432static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
433 struct bin_attribute *bin_attr,
434 char *buf, loff_t pos, size_t count)
435{
436 struct efi_variable *del_var = (struct efi_variable *)buf;
437 struct compat_efi_variable *compat;
438 struct efivar_entry *entry;
439 efi_char16_t *name;
440 efi_guid_t vendor;
441 int err = 0;
442
443 if (!capable(CAP_SYS_ADMIN))
444 return -EACCES;
445
446 if (in_compat_syscall()) {
447 if (count != sizeof(*compat))
448 return -EINVAL;
449
450 compat = (struct compat_efi_variable *)buf;
451 name = compat->VariableName;
452 vendor = compat->VendorGuid;
453 } else {
454 if (count != sizeof(*del_var))
455 return -EINVAL;
456
457 name = del_var->VariableName;
458 vendor = del_var->VendorGuid;
459 }
460
461 if (efivar_entry_iter_begin())
462 return -EINTR;
463 entry = efivar_entry_find(name, vendor, &efivar_sysfs_list, true);
464 if (!entry)
465 err = -EINVAL;
466 else if (__efivar_entry_delete(entry))
467 err = -EIO;
468
469 if (err) {
470 efivar_entry_iter_end();
471 return err;
472 }
473
474 if (!entry->scanning) {
475 efivar_entry_iter_end();
476 efivar_unregister(entry);
477 } else
478 efivar_entry_iter_end();
479
480
481 return count;
482}
483
484
485
486
487
488
489
490static int
491efivar_create_sysfs_entry(struct efivar_entry *new_var)
492{
493 int short_name_size;
494 char *short_name;
495 unsigned long utf8_name_size;
496 efi_char16_t *variable_name = new_var->var.VariableName;
497 int ret;
498
499
500
501
502
503 utf8_name_size = ucs2_utf8size(variable_name);
504 short_name_size = utf8_name_size + 1 + EFI_VARIABLE_GUID_LEN + 1;
505
506 short_name = kmalloc(short_name_size, GFP_KERNEL);
507 if (!short_name)
508 return -ENOMEM;
509
510 ucs2_as_utf8(short_name, variable_name, short_name_size);
511
512
513
514 short_name[utf8_name_size] = '-';
515 efi_guid_to_str(&new_var->var.VendorGuid,
516 short_name + utf8_name_size + 1);
517
518 new_var->kobj.kset = efivars_kset;
519
520 ret = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
521 NULL, "%s", short_name);
522 kfree(short_name);
523 if (ret) {
524 kobject_put(&new_var->kobj);
525 return ret;
526 }
527
528 kobject_uevent(&new_var->kobj, KOBJ_ADD);
529 if (efivar_entry_add(new_var, &efivar_sysfs_list)) {
530 efivar_unregister(new_var);
531 return -EINTR;
532 }
533
534 return 0;
535}
536
537static int
538create_efivars_bin_attributes(void)
539{
540 struct bin_attribute *attr;
541 int error;
542
543
544 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
545 if (!attr)
546 return -ENOMEM;
547
548 attr->attr.name = "new_var";
549 attr->attr.mode = 0200;
550 attr->write = efivar_create;
551 efivars_new_var = attr;
552
553
554 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
555 if (!attr) {
556 error = -ENOMEM;
557 goto out_free;
558 }
559 attr->attr.name = "del_var";
560 attr->attr.mode = 0200;
561 attr->write = efivar_delete;
562 efivars_del_var = attr;
563
564 sysfs_bin_attr_init(efivars_new_var);
565 sysfs_bin_attr_init(efivars_del_var);
566
567
568 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var);
569 if (error) {
570 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
571 " due to error %d\n", error);
572 goto out_free;
573 }
574
575 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var);
576 if (error) {
577 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
578 " due to error %d\n", error);
579 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
580 goto out_free;
581 }
582
583 return 0;
584out_free:
585 kfree(efivars_del_var);
586 efivars_del_var = NULL;
587 kfree(efivars_new_var);
588 efivars_new_var = NULL;
589 return error;
590}
591
592static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor,
593 unsigned long name_size, void *data)
594{
595 struct efivar_entry *entry;
596
597 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
598 if (!entry)
599 return -ENOMEM;
600
601 memcpy(entry->var.VariableName, name, name_size);
602 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
603
604 efivar_create_sysfs_entry(entry);
605
606 return 0;
607}
608
609static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)
610{
611 int err = efivar_entry_remove(entry);
612
613 if (err)
614 return err;
615 efivar_unregister(entry);
616 return 0;
617}
618
619static void efivars_sysfs_exit(void)
620{
621
622 int err;
623
624 err = __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list,
625 NULL, NULL);
626 if (err) {
627 pr_err("efivars: Failed to destroy sysfs entries\n");
628 return;
629 }
630
631 if (efivars_new_var)
632 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
633 if (efivars_del_var)
634 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var);
635 kfree(efivars_new_var);
636 kfree(efivars_del_var);
637 kset_unregister(efivars_kset);
638}
639
640static int efivars_sysfs_init(void)
641{
642 struct kobject *parent_kobj = efivars_kobject();
643 int error = 0;
644
645
646 if (!parent_kobj || !efivar_supports_writes())
647 return 0;
648
649 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
650 EFIVARS_DATE);
651
652 efivars_kset = kset_create_and_add("vars", NULL, parent_kobj);
653 if (!efivars_kset) {
654 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
655 return -ENOMEM;
656 }
657
658 efivar_init(efivars_sysfs_callback, NULL, true, &efivar_sysfs_list);
659
660 error = create_efivars_bin_attributes();
661 if (error) {
662 efivars_sysfs_exit();
663 return error;
664 }
665
666 return 0;
667}
668
669module_init(efivars_sysfs_init);
670module_exit(efivars_sysfs_exit);
671
