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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Originally from efivars.c
4 *
5 * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
6 * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
7 */
8
9#include <linux/capability.h>
10#include <linux/types.h>
11#include <linux/errno.h>
12#include <linux/init.h>
13#include <linux/mm.h>
14#include <linux/module.h>
15#include <linux/string.h>
16#include <linux/smp.h>
17#include <linux/efi.h>
18#include <linux/sysfs.h>
19#include <linux/device.h>
20#include <linux/slab.h>
21#include <linux/ctype.h>
22#include <linux/ucs2_string.h>
23
24/* Private pointer to registered efivars */
25static struct efivars *__efivars;
26
27/*
28 * efivars_lock protects three things:
29 * 1) efivarfs_list and efivars_sysfs_list
30 * 2) ->ops calls
31 * 3) (un)registration of __efivars
32 */
33static DEFINE_SEMAPHORE(efivars_lock);
34
35static bool efivar_wq_enabled = true;
36DECLARE_WORK(efivar_work, NULL);
37EXPORT_SYMBOL_GPL(efivar_work);
38
39static bool
40validate_device_path(efi_char16_t *var_name, int match, u8 *buffer,
41 unsigned long len)
42{
43 struct efi_generic_dev_path *node;
44 int offset = 0;
45
46 node = (struct efi_generic_dev_path *)buffer;
47
48 if (len < sizeof(*node))
49 return false;
50
51 while (offset <= len - sizeof(*node) &&
52 node->length >= sizeof(*node) &&
53 node->length <= len - offset) {
54 offset += node->length;
55
56 if ((node->type == EFI_DEV_END_PATH ||
57 node->type == EFI_DEV_END_PATH2) &&
58 node->sub_type == EFI_DEV_END_ENTIRE)
59 return true;
60
61 node = (struct efi_generic_dev_path *)(buffer + offset);
62 }
63
64 /*
65 * If we're here then either node->length pointed past the end
66 * of the buffer or we reached the end of the buffer without
67 * finding a device path end node.
68 */
69 return false;
70}
71
72static bool
73validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer,
74 unsigned long len)
75{
76 /* An array of 16-bit integers */
77 if ((len % 2) != 0)
78 return false;
79
80 return true;
81}
82
83static bool
84validate_load_option(efi_char16_t *var_name, int match, u8 *buffer,
85 unsigned long len)
86{
87 u16 filepathlength;
88 int i, desclength = 0, namelen;
89
90 namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN);
91
92 /* Either "Boot" or "Driver" followed by four digits of hex */
93 for (i = match; i < match+4; i++) {
94 if (var_name[i] > 127 ||
95 hex_to_bin(var_name[i] & 0xff) < 0)
96 return true;
97 }
98
99 /* Reject it if there's 4 digits of hex and then further content */
100 if (namelen > match + 4)
101 return false;
102
103 /* A valid entry must be at least 8 bytes */
104 if (len < 8)
105 return false;
106
107 filepathlength = buffer[4] | buffer[5] << 8;
108
109 /*
110 * There's no stored length for the description, so it has to be
111 * found by hand
112 */
113 desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
114
115 /* Each boot entry must have a descriptor */
116 if (!desclength)
117 return false;
118
119 /*
120 * If the sum of the length of the description, the claimed filepath
121 * length and the original header are greater than the length of the
122 * variable, it's malformed
123 */
124 if ((desclength + filepathlength + 6) > len)
125 return false;
126
127 /*
128 * And, finally, check the filepath
129 */
130 return validate_device_path(var_name, match, buffer + desclength + 6,
131 filepathlength);
132}
133
134static bool
135validate_uint16(efi_char16_t *var_name, int match, u8 *buffer,
136 unsigned long len)
137{
138 /* A single 16-bit integer */
139 if (len != 2)
140 return false;
141
142 return true;
143}
144
145static bool
146validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer,
147 unsigned long len)
148{
149 int i;
150
151 for (i = 0; i < len; i++) {
152 if (buffer[i] > 127)
153 return false;
154
155 if (buffer[i] == 0)
156 return true;
157 }
158
159 return false;
160}
161
162struct variable_validate {
163 efi_guid_t vendor;
164 char *name;
165 bool (*validate)(efi_char16_t *var_name, int match, u8 *data,
166 unsigned long len);
167};
168
169/*
170 * This is the list of variables we need to validate, as well as the
171 * whitelist for what we think is safe not to default to immutable.
172 *
173 * If it has a validate() method that's not NULL, it'll go into the
174 * validation routine. If not, it is assumed valid, but still used for
175 * whitelisting.
176 *
177 * Note that it's sorted by {vendor,name}, but globbed names must come after
178 * any other name with the same prefix.
179 */
180static const struct variable_validate variable_validate[] = {
181 { EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 },
182 { EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order },
183 { EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option },
184 { EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order },
185 { EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option },
186 { EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path },
187 { EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path },
188 { EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path },
189 { EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path },
190 { EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path },
191 { EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path },
192 { EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string },
193 { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL },
194 { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string },
195 { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 },
196 { LINUX_EFI_CRASH_GUID, "*", NULL },
197 { NULL_GUID, "", NULL },
198};
199
200/*
201 * Check if @var_name matches the pattern given in @match_name.
202 *
203 * @var_name: an array of @len non-NUL characters.
204 * @match_name: a NUL-terminated pattern string, optionally ending in "*". A
205 * final "*" character matches any trailing characters @var_name,
206 * including the case when there are none left in @var_name.
207 * @match: on output, the number of non-wildcard characters in @match_name
208 * that @var_name matches, regardless of the return value.
209 * @return: whether @var_name fully matches @match_name.
210 */
211static bool
212variable_matches(const char *var_name, size_t len, const char *match_name,
213 int *match)
214{
215 for (*match = 0; ; (*match)++) {
216 char c = match_name[*match];
217
218 switch (c) {
219 case '*':
220 /* Wildcard in @match_name means we've matched. */
221 return true;
222
223 case '\0':
224 /* @match_name has ended. Has @var_name too? */
225 return (*match == len);
226
227 default:
228 /*
229 * We've reached a non-wildcard char in @match_name.
230 * Continue only if there's an identical character in
231 * @var_name.
232 */
233 if (*match < len && c == var_name[*match])
234 continue;
235 return false;
236 }
237 }
238}
239
240bool
241efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
242 unsigned long data_size)
243{
244 int i;
245 unsigned long utf8_size;
246 u8 *utf8_name;
247
248 utf8_size = ucs2_utf8size(var_name);
249 utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL);
250 if (!utf8_name)
251 return false;
252
253 ucs2_as_utf8(utf8_name, var_name, utf8_size);
254 utf8_name[utf8_size] = '\0';
255
256 for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
257 const char *name = variable_validate[i].name;
258 int match = 0;
259
260 if (efi_guidcmp(vendor, variable_validate[i].vendor))
261 continue;
262
263 if (variable_matches(utf8_name, utf8_size+1, name, &match)) {
264 if (variable_validate[i].validate == NULL)
265 break;
266 kfree(utf8_name);
267 return variable_validate[i].validate(var_name, match,
268 data, data_size);
269 }
270 }
271 kfree(utf8_name);
272 return true;
273}
274EXPORT_SYMBOL_GPL(efivar_validate);
275
276bool
277efivar_variable_is_removable(efi_guid_t vendor, const char *var_name,
278 size_t len)
279{
280 int i;
281 bool found = false;
282 int match = 0;
283
284 /*
285 * Check if our variable is in the validated variables list
286 */
287 for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
288 if (efi_guidcmp(variable_validate[i].vendor, vendor))
289 continue;
290
291 if (variable_matches(var_name, len,
292 variable_validate[i].name, &match)) {
293 found = true;
294 break;
295 }
296 }
297
298 /*
299 * If it's in our list, it is removable.
300 */
301 return found;
302}
303EXPORT_SYMBOL_GPL(efivar_variable_is_removable);
304
305static efi_status_t
306check_var_size(u32 attributes, unsigned long size)
307{
308 const struct efivar_operations *fops;
309
310 if (!__efivars)
311 return EFI_UNSUPPORTED;
312
313 fops = __efivars->ops;
314
315 if (!fops->query_variable_store)
316 return EFI_UNSUPPORTED;
317
318 return fops->query_variable_store(attributes, size, false);
319}
320
321static efi_status_t
322check_var_size_nonblocking(u32 attributes, unsigned long size)
323{
324 const struct efivar_operations *fops;
325
326 if (!__efivars)
327 return EFI_UNSUPPORTED;
328
329 fops = __efivars->ops;
330
331 if (!fops->query_variable_store)
332 return EFI_UNSUPPORTED;
333
334 return fops->query_variable_store(attributes, size, true);
335}
336
337static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
338 struct list_head *head)
339{
340 struct efivar_entry *entry, *n;
341 unsigned long strsize1, strsize2;
342 bool found = false;
343
344 strsize1 = ucs2_strsize(variable_name, 1024);
345 list_for_each_entry_safe(entry, n, head, list) {
346 strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
347 if (strsize1 == strsize2 &&
348 !memcmp(variable_name, &(entry->var.VariableName),
349 strsize2) &&
350 !efi_guidcmp(entry->var.VendorGuid,
351 *vendor)) {
352 found = true;
353 break;
354 }
355 }
356 return found;
357}
358
359/*
360 * Returns the size of variable_name, in bytes, including the
361 * terminating NULL character, or variable_name_size if no NULL
362 * character is found among the first variable_name_size bytes.
363 */
364static unsigned long var_name_strnsize(efi_char16_t *variable_name,
365 unsigned long variable_name_size)
366{
367 unsigned long len;
368 efi_char16_t c;
369
370 /*
371 * The variable name is, by definition, a NULL-terminated
372 * string, so make absolutely sure that variable_name_size is
373 * the value we expect it to be. If not, return the real size.
374 */
375 for (len = 2; len <= variable_name_size; len += sizeof(c)) {
376 c = variable_name[(len / sizeof(c)) - 1];
377 if (!c)
378 break;
379 }
380
381 return min(len, variable_name_size);
382}
383
384/*
385 * Print a warning when duplicate EFI variables are encountered and
386 * disable the sysfs workqueue since the firmware is buggy.
387 */
388static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
389 unsigned long len16)
390{
391 size_t i, len8 = len16 / sizeof(efi_char16_t);
392 char *str8;
393
394 /*
395 * Disable the workqueue since the algorithm it uses for
396 * detecting new variables won't work with this buggy
397 * implementation of GetNextVariableName().
398 */
399 efivar_wq_enabled = false;
400
401 str8 = kzalloc(len8, GFP_KERNEL);
402 if (!str8)
403 return;
404
405 for (i = 0; i < len8; i++)
406 str8[i] = str16[i];
407
408 printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
409 str8, vendor_guid);
410 kfree(str8);
411}
412
413/**
414 * efivar_init - build the initial list of EFI variables
415 * @func: callback function to invoke for every variable
416 * @data: function-specific data to pass to @func
417 * @atomic: do we need to execute the @func-loop atomically?
418 * @duplicates: error if we encounter duplicates on @head?
419 * @head: initialised head of variable list
420 *
421 * Get every EFI variable from the firmware and invoke @func. @func
422 * should call efivar_entry_add() to build the list of variables.
423 *
424 * Returns 0 on success, or a kernel error code on failure.
425 */
426int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
427 void *data, bool duplicates, struct list_head *head)
428{
429 const struct efivar_operations *ops;
430 unsigned long variable_name_size = 1024;
431 efi_char16_t *variable_name;
432 efi_status_t status;
433 efi_guid_t vendor_guid;
434 int err = 0;
435
436 if (!__efivars)
437 return -EFAULT;
438
439 ops = __efivars->ops;
440
441 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
442 if (!variable_name) {
443 printk(KERN_ERR "efivars: Memory allocation failed.\n");
444 return -ENOMEM;
445 }
446
447 if (down_interruptible(&efivars_lock)) {
448 err = -EINTR;
449 goto free;
450 }
451
452 /*
453 * Per EFI spec, the maximum storage allocated for both
454 * the variable name and variable data is 1024 bytes.
455 */
456
457 do {
458 variable_name_size = 1024;
459
460 status = ops->get_next_variable(&variable_name_size,
461 variable_name,
462 &vendor_guid);
463 switch (status) {
464 case EFI_SUCCESS:
465 if (duplicates)
466 up(&efivars_lock);
467
468 variable_name_size = var_name_strnsize(variable_name,
469 variable_name_size);
470
471 /*
472 * Some firmware implementations return the
473 * same variable name on multiple calls to
474 * get_next_variable(). Terminate the loop
475 * immediately as there is no guarantee that
476 * we'll ever see a different variable name,
477 * and may end up looping here forever.
478 */
479 if (duplicates &&
480 variable_is_present(variable_name, &vendor_guid,
481 head)) {
482 dup_variable_bug(variable_name, &vendor_guid,
483 variable_name_size);
484 status = EFI_NOT_FOUND;
485 } else {
486 err = func(variable_name, vendor_guid,
487 variable_name_size, data);
488 if (err)
489 status = EFI_NOT_FOUND;
490 }
491
492 if (duplicates) {
493 if (down_interruptible(&efivars_lock)) {
494 err = -EINTR;
495 goto free;
496 }
497 }
498
499 break;
500 case EFI_NOT_FOUND:
501 break;
502 default:
503 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
504 status);
505 status = EFI_NOT_FOUND;
506 break;
507 }
508
509 } while (status != EFI_NOT_FOUND);
510
511 up(&efivars_lock);
512free:
513 kfree(variable_name);
514
515 return err;
516}
517EXPORT_SYMBOL_GPL(efivar_init);
518
519/**
520 * efivar_entry_add - add entry to variable list
521 * @entry: entry to add to list
522 * @head: list head
523 *
524 * Returns 0 on success, or a kernel error code on failure.
525 */
526int efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
527{
528 if (down_interruptible(&efivars_lock))
529 return -EINTR;
530 list_add(&entry->list, head);
531 up(&efivars_lock);
532
533 return 0;
534}
535EXPORT_SYMBOL_GPL(efivar_entry_add);
536
537/**
538 * efivar_entry_remove - remove entry from variable list
539 * @entry: entry to remove from list
540 *
541 * Returns 0 on success, or a kernel error code on failure.
542 */
543int efivar_entry_remove(struct efivar_entry *entry)
544{
545 if (down_interruptible(&efivars_lock))
546 return -EINTR;
547 list_del(&entry->list);
548 up(&efivars_lock);
549
550 return 0;
551}
552EXPORT_SYMBOL_GPL(efivar_entry_remove);
553
554/*
555 * efivar_entry_list_del_unlock - remove entry from variable list
556 * @entry: entry to remove
557 *
558 * Remove @entry from the variable list and release the list lock.
559 *
560 * NOTE: slightly weird locking semantics here - we expect to be
561 * called with the efivars lock already held, and we release it before
562 * returning. This is because this function is usually called after
563 * set_variable() while the lock is still held.
564 */
565static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
566{
567 list_del(&entry->list);
568 up(&efivars_lock);
569}
570
571/**
572 * __efivar_entry_delete - delete an EFI variable
573 * @entry: entry containing EFI variable to delete
574 *
575 * Delete the variable from the firmware but leave @entry on the
576 * variable list.
577 *
578 * This function differs from efivar_entry_delete() because it does
579 * not remove @entry from the variable list. Also, it is safe to be
580 * called from within a efivar_entry_iter_begin() and
581 * efivar_entry_iter_end() region, unlike efivar_entry_delete().
582 *
583 * Returns 0 on success, or a converted EFI status code if
584 * set_variable() fails.
585 */
586int __efivar_entry_delete(struct efivar_entry *entry)
587{
588 efi_status_t status;
589
590 if (!__efivars)
591 return -EINVAL;
592
593 status = __efivars->ops->set_variable(entry->var.VariableName,
594 &entry->var.VendorGuid,
595 0, 0, NULL);
596
597 return efi_status_to_err(status);
598}
599EXPORT_SYMBOL_GPL(__efivar_entry_delete);
600
601/**
602 * efivar_entry_delete - delete variable and remove entry from list
603 * @entry: entry containing variable to delete
604 *
605 * Delete the variable from the firmware and remove @entry from the
606 * variable list. It is the caller's responsibility to free @entry
607 * once we return.
608 *
609 * Returns 0 on success, -EINTR if we can't grab the semaphore,
610 * converted EFI status code if set_variable() fails.
611 */
612int efivar_entry_delete(struct efivar_entry *entry)
613{
614 const struct efivar_operations *ops;
615 efi_status_t status;
616
617 if (down_interruptible(&efivars_lock))
618 return -EINTR;
619
620 if (!__efivars) {
621 up(&efivars_lock);
622 return -EINVAL;
623 }
624 ops = __efivars->ops;
625 status = ops->set_variable(entry->var.VariableName,
626 &entry->var.VendorGuid,
627 0, 0, NULL);
628 if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
629 up(&efivars_lock);
630 return efi_status_to_err(status);
631 }
632
633 efivar_entry_list_del_unlock(entry);
634 return 0;
635}
636EXPORT_SYMBOL_GPL(efivar_entry_delete);
637
638/**
639 * efivar_entry_set - call set_variable()
640 * @entry: entry containing the EFI variable to write
641 * @attributes: variable attributes
642 * @size: size of @data buffer
643 * @data: buffer containing variable data
644 * @head: head of variable list
645 *
646 * Calls set_variable() for an EFI variable. If creating a new EFI
647 * variable, this function is usually followed by efivar_entry_add().
648 *
649 * Before writing the variable, the remaining EFI variable storage
650 * space is checked to ensure there is enough room available.
651 *
652 * If @head is not NULL a lookup is performed to determine whether
653 * the entry is already on the list.
654 *
655 * Returns 0 on success, -EINTR if we can't grab the semaphore,
656 * -EEXIST if a lookup is performed and the entry already exists on
657 * the list, or a converted EFI status code if set_variable() fails.
658 */
659int efivar_entry_set(struct efivar_entry *entry, u32 attributes,
660 unsigned long size, void *data, struct list_head *head)
661{
662 const struct efivar_operations *ops;
663 efi_status_t status;
664 efi_char16_t *name = entry->var.VariableName;
665 efi_guid_t vendor = entry->var.VendorGuid;
666
667 if (down_interruptible(&efivars_lock))
668 return -EINTR;
669
670 if (!__efivars) {
671 up(&efivars_lock);
672 return -EINVAL;
673 }
674 ops = __efivars->ops;
675 if (head && efivar_entry_find(name, vendor, head, false)) {
676 up(&efivars_lock);
677 return -EEXIST;
678 }
679
680 status = check_var_size(attributes, size + ucs2_strsize(name, 1024));
681 if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
682 status = ops->set_variable(name, &vendor,
683 attributes, size, data);
684
685 up(&efivars_lock);
686
687 return efi_status_to_err(status);
688
689}
690EXPORT_SYMBOL_GPL(efivar_entry_set);
691
692/*
693 * efivar_entry_set_nonblocking - call set_variable_nonblocking()
694 *
695 * This function is guaranteed to not block and is suitable for calling
696 * from crash/panic handlers.
697 *
698 * Crucially, this function will not block if it cannot acquire
699 * efivars_lock. Instead, it returns -EBUSY.
700 */
701static int
702efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor,
703 u32 attributes, unsigned long size, void *data)
704{
705 const struct efivar_operations *ops;
706 efi_status_t status;
707
708 if (down_trylock(&efivars_lock))
709 return -EBUSY;
710
711 if (!__efivars) {
712 up(&efivars_lock);
713 return -EINVAL;
714 }
715
716 status = check_var_size_nonblocking(attributes,
717 size + ucs2_strsize(name, 1024));
718 if (status != EFI_SUCCESS) {
719 up(&efivars_lock);
720 return -ENOSPC;
721 }
722
723 ops = __efivars->ops;
724 status = ops->set_variable_nonblocking(name, &vendor, attributes,
725 size, data);
726
727 up(&efivars_lock);
728 return efi_status_to_err(status);
729}
730
731/**
732 * efivar_entry_set_safe - call set_variable() if enough space in firmware
733 * @name: buffer containing the variable name
734 * @vendor: variable vendor guid
735 * @attributes: variable attributes
736 * @block: can we block in this context?
737 * @size: size of @data buffer
738 * @data: buffer containing variable data
739 *
740 * Ensures there is enough free storage in the firmware for this variable, and
741 * if so, calls set_variable(). If creating a new EFI variable, this function
742 * is usually followed by efivar_entry_add().
743 *
744 * Returns 0 on success, -ENOSPC if the firmware does not have enough
745 * space for set_variable() to succeed, or a converted EFI status code
746 * if set_variable() fails.
747 */
748int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes,
749 bool block, unsigned long size, void *data)
750{
751 const struct efivar_operations *ops;
752 efi_status_t status;
753
754 if (!__efivars)
755 return -EINVAL;
756
757 ops = __efivars->ops;
758 if (!ops->query_variable_store)
759 return -ENOSYS;
760
761 /*
762 * If the EFI variable backend provides a non-blocking
763 * ->set_variable() operation and we're in a context where we
764 * cannot block, then we need to use it to avoid live-locks,
765 * since the implication is that the regular ->set_variable()
766 * will block.
767 *
768 * If no ->set_variable_nonblocking() is provided then
769 * ->set_variable() is assumed to be non-blocking.
770 */
771 if (!block && ops->set_variable_nonblocking)
772 return efivar_entry_set_nonblocking(name, vendor, attributes,
773 size, data);
774
775 if (!block) {
776 if (down_trylock(&efivars_lock))
777 return -EBUSY;
778 } else {
779 if (down_interruptible(&efivars_lock))
780 return -EINTR;
781 }
782
783 status = check_var_size(attributes, size + ucs2_strsize(name, 1024));
784 if (status != EFI_SUCCESS) {
785 up(&efivars_lock);
786 return -ENOSPC;
787 }
788
789 status = ops->set_variable(name, &vendor, attributes, size, data);
790
791 up(&efivars_lock);
792
793 return efi_status_to_err(status);
794}
795EXPORT_SYMBOL_GPL(efivar_entry_set_safe);
796
797/**
798 * efivar_entry_find - search for an entry
799 * @name: the EFI variable name
800 * @guid: the EFI variable vendor's guid
801 * @head: head of the variable list
802 * @remove: should we remove the entry from the list?
803 *
804 * Search for an entry on the variable list that has the EFI variable
805 * name @name and vendor guid @guid. If an entry is found on the list
806 * and @remove is true, the entry is removed from the list.
807 *
808 * The caller MUST call efivar_entry_iter_begin() and
809 * efivar_entry_iter_end() before and after the invocation of this
810 * function, respectively.
811 *
812 * Returns the entry if found on the list, %NULL otherwise.
813 */
814struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid,
815 struct list_head *head, bool remove)
816{
817 struct efivar_entry *entry, *n;
818 int strsize1, strsize2;
819 bool found = false;
820
821 list_for_each_entry_safe(entry, n, head, list) {
822 strsize1 = ucs2_strsize(name, 1024);
823 strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
824 if (strsize1 == strsize2 &&
825 !memcmp(name, &(entry->var.VariableName), strsize1) &&
826 !efi_guidcmp(guid, entry->var.VendorGuid)) {
827 found = true;
828 break;
829 }
830 }
831
832 if (!found)
833 return NULL;
834
835 if (remove) {
836 if (entry->scanning) {
837 /*
838 * The entry will be deleted
839 * after scanning is completed.
840 */
841 entry->deleting = true;
842 } else
843 list_del(&entry->list);
844 }
845
846 return entry;
847}
848EXPORT_SYMBOL_GPL(efivar_entry_find);
849
850/**
851 * efivar_entry_size - obtain the size of a variable
852 * @entry: entry for this variable
853 * @size: location to store the variable's size
854 */
855int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
856{
857 const struct efivar_operations *ops;
858 efi_status_t status;
859
860 *size = 0;
861
862 if (down_interruptible(&efivars_lock))
863 return -EINTR;
864 if (!__efivars) {
865 up(&efivars_lock);
866 return -EINVAL;
867 }
868 ops = __efivars->ops;
869 status = ops->get_variable(entry->var.VariableName,
870 &entry->var.VendorGuid, NULL, size, NULL);
871 up(&efivars_lock);
872
873 if (status != EFI_BUFFER_TOO_SMALL)
874 return efi_status_to_err(status);
875
876 return 0;
877}
878EXPORT_SYMBOL_GPL(efivar_entry_size);
879
880/**
881 * __efivar_entry_get - call get_variable()
882 * @entry: read data for this variable
883 * @attributes: variable attributes
884 * @size: size of @data buffer
885 * @data: buffer to store variable data
886 *
887 * The caller MUST call efivar_entry_iter_begin() and
888 * efivar_entry_iter_end() before and after the invocation of this
889 * function, respectively.
890 */
891int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
892 unsigned long *size, void *data)
893{
894 efi_status_t status;
895
896 if (!__efivars)
897 return -EINVAL;
898
899 status = __efivars->ops->get_variable(entry->var.VariableName,
900 &entry->var.VendorGuid,
901 attributes, size, data);
902
903 return efi_status_to_err(status);
904}
905EXPORT_SYMBOL_GPL(__efivar_entry_get);
906
907/**
908 * efivar_entry_get - call get_variable()
909 * @entry: read data for this variable
910 * @attributes: variable attributes
911 * @size: size of @data buffer
912 * @data: buffer to store variable data
913 */
914int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
915 unsigned long *size, void *data)
916{
917 efi_status_t status;
918
919 if (down_interruptible(&efivars_lock))
920 return -EINTR;
921
922 if (!__efivars) {
923 up(&efivars_lock);
924 return -EINVAL;
925 }
926
927 status = __efivars->ops->get_variable(entry->var.VariableName,
928 &entry->var.VendorGuid,
929 attributes, size, data);
930 up(&efivars_lock);
931
932 return efi_status_to_err(status);
933}
934EXPORT_SYMBOL_GPL(efivar_entry_get);
935
936/**
937 * efivar_entry_set_get_size - call set_variable() and get new size (atomic)
938 * @entry: entry containing variable to set and get
939 * @attributes: attributes of variable to be written
940 * @size: size of data buffer
941 * @data: buffer containing data to write
942 * @set: did the set_variable() call succeed?
943 *
944 * This is a pretty special (complex) function. See efivarfs_file_write().
945 *
946 * Atomically call set_variable() for @entry and if the call is
947 * successful, return the new size of the variable from get_variable()
948 * in @size. The success of set_variable() is indicated by @set.
949 *
950 * Returns 0 on success, -EINVAL if the variable data is invalid,
951 * -ENOSPC if the firmware does not have enough available space, or a
952 * converted EFI status code if either of set_variable() or
953 * get_variable() fail.
954 *
955 * If the EFI variable does not exist when calling set_variable()
956 * (EFI_NOT_FOUND), @entry is removed from the variable list.
957 */
958int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
959 unsigned long *size, void *data, bool *set)
960{
961 const struct efivar_operations *ops;
962 efi_char16_t *name = entry->var.VariableName;
963 efi_guid_t *vendor = &entry->var.VendorGuid;
964 efi_status_t status;
965 int err;
966
967 *set = false;
968
969 if (efivar_validate(*vendor, name, data, *size) == false)
970 return -EINVAL;
971
972 /*
973 * The lock here protects the get_variable call, the conditional
974 * set_variable call, and removal of the variable from the efivars
975 * list (in the case of an authenticated delete).
976 */
977 if (down_interruptible(&efivars_lock))
978 return -EINTR;
979
980 if (!__efivars) {
981 err = -EINVAL;
982 goto out;
983 }
984
985 /*
986 * Ensure that the available space hasn't shrunk below the safe level
987 */
988 status = check_var_size(attributes, *size + ucs2_strsize(name, 1024));
989 if (status != EFI_SUCCESS) {
990 if (status != EFI_UNSUPPORTED) {
991 err = efi_status_to_err(status);
992 goto out;
993 }
994
995 if (*size > 65536) {
996 err = -ENOSPC;
997 goto out;
998 }
999 }
1000
1001 ops = __efivars->ops;
1002
1003 status = ops->set_variable(name, vendor, attributes, *size, data);
1004 if (status != EFI_SUCCESS) {
1005 err = efi_status_to_err(status);
1006 goto out;
1007 }
1008
1009 *set = true;
1010
1011 /*
1012 * Writing to the variable may have caused a change in size (which
1013 * could either be an append or an overwrite), or the variable to be
1014 * deleted. Perform a GetVariable() so we can tell what actually
1015 * happened.
1016 */
1017 *size = 0;
1018 status = ops->get_variable(entry->var.VariableName,
1019 &entry->var.VendorGuid,
1020 NULL, size, NULL);
1021
1022 if (status == EFI_NOT_FOUND)
1023 efivar_entry_list_del_unlock(entry);
1024 else
1025 up(&efivars_lock);
1026
1027 if (status && status != EFI_BUFFER_TOO_SMALL)
1028 return efi_status_to_err(status);
1029
1030 return 0;
1031
1032out:
1033 up(&efivars_lock);
1034 return err;
1035
1036}
1037EXPORT_SYMBOL_GPL(efivar_entry_set_get_size);
1038
1039/**
1040 * efivar_entry_iter_begin - begin iterating the variable list
1041 *
1042 * Lock the variable list to prevent entry insertion and removal until
1043 * efivar_entry_iter_end() is called. This function is usually used in
1044 * conjunction with __efivar_entry_iter() or efivar_entry_iter().
1045 */
1046int efivar_entry_iter_begin(void)
1047{
1048 return down_interruptible(&efivars_lock);
1049}
1050EXPORT_SYMBOL_GPL(efivar_entry_iter_begin);
1051
1052/**
1053 * efivar_entry_iter_end - finish iterating the variable list
1054 *
1055 * Unlock the variable list and allow modifications to the list again.
1056 */
1057void efivar_entry_iter_end(void)
1058{
1059 up(&efivars_lock);
1060}
1061EXPORT_SYMBOL_GPL(efivar_entry_iter_end);
1062
1063/**
1064 * __efivar_entry_iter - iterate over variable list
1065 * @func: callback function
1066 * @head: head of the variable list
1067 * @data: function-specific data to pass to callback
1068 * @prev: entry to begin iterating from
1069 *
1070 * Iterate over the list of EFI variables and call @func with every
1071 * entry on the list. It is safe for @func to remove entries in the
1072 * list via efivar_entry_delete().
1073 *
1074 * You MUST call efivar_entry_iter_begin() before this function, and
1075 * efivar_entry_iter_end() afterwards.
1076 *
1077 * It is possible to begin iteration from an arbitrary entry within
1078 * the list by passing @prev. @prev is updated on return to point to
1079 * the last entry passed to @func. To begin iterating from the
1080 * beginning of the list @prev must be %NULL.
1081 *
1082 * The restrictions for @func are the same as documented for
1083 * efivar_entry_iter().
1084 */
1085int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
1086 struct list_head *head, void *data,
1087 struct efivar_entry **prev)
1088{
1089 struct efivar_entry *entry, *n;
1090 int err = 0;
1091
1092 if (!prev || !*prev) {
1093 list_for_each_entry_safe(entry, n, head, list) {
1094 err = func(entry, data);
1095 if (err)
1096 break;
1097 }
1098
1099 if (prev)
1100 *prev = entry;
1101
1102 return err;
1103 }
1104
1105
1106 list_for_each_entry_safe_continue((*prev), n, head, list) {
1107 err = func(*prev, data);
1108 if (err)
1109 break;
1110 }
1111
1112 return err;
1113}
1114EXPORT_SYMBOL_GPL(__efivar_entry_iter);
1115
1116/**
1117 * efivar_entry_iter - iterate over variable list
1118 * @func: callback function
1119 * @head: head of variable list
1120 * @data: function-specific data to pass to callback
1121 *
1122 * Iterate over the list of EFI variables and call @func with every
1123 * entry on the list. It is safe for @func to remove entries in the
1124 * list via efivar_entry_delete() while iterating.
1125 *
1126 * Some notes for the callback function:
1127 * - a non-zero return value indicates an error and terminates the loop
1128 * - @func is called from atomic context
1129 */
1130int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
1131 struct list_head *head, void *data)
1132{
1133 int err = 0;
1134
1135 err = efivar_entry_iter_begin();
1136 if (err)
1137 return err;
1138 err = __efivar_entry_iter(func, head, data, NULL);
1139 efivar_entry_iter_end();
1140
1141 return err;
1142}
1143EXPORT_SYMBOL_GPL(efivar_entry_iter);
1144
1145/**
1146 * efivars_kobject - get the kobject for the registered efivars
1147 *
1148 * If efivars_register() has not been called we return NULL,
1149 * otherwise return the kobject used at registration time.
1150 */
1151struct kobject *efivars_kobject(void)
1152{
1153 if (!__efivars)
1154 return NULL;
1155
1156 return __efivars->kobject;
1157}
1158EXPORT_SYMBOL_GPL(efivars_kobject);
1159
1160/**
1161 * efivar_run_worker - schedule the efivar worker thread
1162 */
1163void efivar_run_worker(void)
1164{
1165 if (efivar_wq_enabled)
1166 schedule_work(&efivar_work);
1167}
1168EXPORT_SYMBOL_GPL(efivar_run_worker);
1169
1170/**
1171 * efivars_register - register an efivars
1172 * @efivars: efivars to register
1173 * @ops: efivars operations
1174 * @kobject: @efivars-specific kobject
1175 *
1176 * Only a single efivars can be registered at any time.
1177 */
1178int efivars_register(struct efivars *efivars,
1179 const struct efivar_operations *ops,
1180 struct kobject *kobject)
1181{
1182 if (down_interruptible(&efivars_lock))
1183 return -EINTR;
1184
1185 efivars->ops = ops;
1186 efivars->kobject = kobject;
1187
1188 __efivars = efivars;
1189
1190 pr_info("Registered efivars operations\n");
1191
1192 up(&efivars_lock);
1193
1194 return 0;
1195}
1196EXPORT_SYMBOL_GPL(efivars_register);
1197
1198/**
1199 * efivars_unregister - unregister an efivars
1200 * @efivars: efivars to unregister
1201 *
1202 * The caller must have already removed every entry from the list,
1203 * failure to do so is an error.
1204 */
1205int efivars_unregister(struct efivars *efivars)
1206{
1207 int rv;
1208
1209 if (down_interruptible(&efivars_lock))
1210 return -EINTR;
1211
1212 if (!__efivars) {
1213 printk(KERN_ERR "efivars not registered\n");
1214 rv = -EINVAL;
1215 goto out;
1216 }
1217
1218 if (__efivars != efivars) {
1219 rv = -EINVAL;
1220 goto out;
1221 }
1222
1223 pr_info("Unregistered efivars operations\n");
1224 __efivars = NULL;
1225
1226 rv = 0;
1227out:
1228 up(&efivars_lock);
1229 return rv;
1230}
1231EXPORT_SYMBOL_GPL(efivars_unregister);
1232
1233int efivar_supports_writes(void)
1234{
1235 return __efivars && __efivars->ops->set_variable;
1236}
1237EXPORT_SYMBOL_GPL(efivar_supports_writes);
1/*
2 * Originally from efivars.c
3 *
4 * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
5 * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#include <linux/capability.h>
23#include <linux/types.h>
24#include <linux/errno.h>
25#include <linux/init.h>
26#include <linux/mm.h>
27#include <linux/module.h>
28#include <linux/string.h>
29#include <linux/smp.h>
30#include <linux/efi.h>
31#include <linux/sysfs.h>
32#include <linux/device.h>
33#include <linux/slab.h>
34#include <linux/ctype.h>
35#include <linux/ucs2_string.h>
36
37/* Private pointer to registered efivars */
38static struct efivars *__efivars;
39
40static bool efivar_wq_enabled = true;
41DECLARE_WORK(efivar_work, NULL);
42EXPORT_SYMBOL_GPL(efivar_work);
43
44static bool
45validate_device_path(efi_char16_t *var_name, int match, u8 *buffer,
46 unsigned long len)
47{
48 struct efi_generic_dev_path *node;
49 int offset = 0;
50
51 node = (struct efi_generic_dev_path *)buffer;
52
53 if (len < sizeof(*node))
54 return false;
55
56 while (offset <= len - sizeof(*node) &&
57 node->length >= sizeof(*node) &&
58 node->length <= len - offset) {
59 offset += node->length;
60
61 if ((node->type == EFI_DEV_END_PATH ||
62 node->type == EFI_DEV_END_PATH2) &&
63 node->sub_type == EFI_DEV_END_ENTIRE)
64 return true;
65
66 node = (struct efi_generic_dev_path *)(buffer + offset);
67 }
68
69 /*
70 * If we're here then either node->length pointed past the end
71 * of the buffer or we reached the end of the buffer without
72 * finding a device path end node.
73 */
74 return false;
75}
76
77static bool
78validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer,
79 unsigned long len)
80{
81 /* An array of 16-bit integers */
82 if ((len % 2) != 0)
83 return false;
84
85 return true;
86}
87
88static bool
89validate_load_option(efi_char16_t *var_name, int match, u8 *buffer,
90 unsigned long len)
91{
92 u16 filepathlength;
93 int i, desclength = 0, namelen;
94
95 namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN);
96
97 /* Either "Boot" or "Driver" followed by four digits of hex */
98 for (i = match; i < match+4; i++) {
99 if (var_name[i] > 127 ||
100 hex_to_bin(var_name[i] & 0xff) < 0)
101 return true;
102 }
103
104 /* Reject it if there's 4 digits of hex and then further content */
105 if (namelen > match + 4)
106 return false;
107
108 /* A valid entry must be at least 8 bytes */
109 if (len < 8)
110 return false;
111
112 filepathlength = buffer[4] | buffer[5] << 8;
113
114 /*
115 * There's no stored length for the description, so it has to be
116 * found by hand
117 */
118 desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
119
120 /* Each boot entry must have a descriptor */
121 if (!desclength)
122 return false;
123
124 /*
125 * If the sum of the length of the description, the claimed filepath
126 * length and the original header are greater than the length of the
127 * variable, it's malformed
128 */
129 if ((desclength + filepathlength + 6) > len)
130 return false;
131
132 /*
133 * And, finally, check the filepath
134 */
135 return validate_device_path(var_name, match, buffer + desclength + 6,
136 filepathlength);
137}
138
139static bool
140validate_uint16(efi_char16_t *var_name, int match, u8 *buffer,
141 unsigned long len)
142{
143 /* A single 16-bit integer */
144 if (len != 2)
145 return false;
146
147 return true;
148}
149
150static bool
151validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer,
152 unsigned long len)
153{
154 int i;
155
156 for (i = 0; i < len; i++) {
157 if (buffer[i] > 127)
158 return false;
159
160 if (buffer[i] == 0)
161 return true;
162 }
163
164 return false;
165}
166
167struct variable_validate {
168 efi_guid_t vendor;
169 char *name;
170 bool (*validate)(efi_char16_t *var_name, int match, u8 *data,
171 unsigned long len);
172};
173
174/*
175 * This is the list of variables we need to validate, as well as the
176 * whitelist for what we think is safe not to default to immutable.
177 *
178 * If it has a validate() method that's not NULL, it'll go into the
179 * validation routine. If not, it is assumed valid, but still used for
180 * whitelisting.
181 *
182 * Note that it's sorted by {vendor,name}, but globbed names must come after
183 * any other name with the same prefix.
184 */
185static const struct variable_validate variable_validate[] = {
186 { EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 },
187 { EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order },
188 { EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option },
189 { EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order },
190 { EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option },
191 { EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path },
192 { EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path },
193 { EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path },
194 { EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path },
195 { EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path },
196 { EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path },
197 { EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string },
198 { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL },
199 { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string },
200 { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 },
201 { LINUX_EFI_CRASH_GUID, "*", NULL },
202 { NULL_GUID, "", NULL },
203};
204
205/*
206 * Check if @var_name matches the pattern given in @match_name.
207 *
208 * @var_name: an array of @len non-NUL characters.
209 * @match_name: a NUL-terminated pattern string, optionally ending in "*". A
210 * final "*" character matches any trailing characters @var_name,
211 * including the case when there are none left in @var_name.
212 * @match: on output, the number of non-wildcard characters in @match_name
213 * that @var_name matches, regardless of the return value.
214 * @return: whether @var_name fully matches @match_name.
215 */
216static bool
217variable_matches(const char *var_name, size_t len, const char *match_name,
218 int *match)
219{
220 for (*match = 0; ; (*match)++) {
221 char c = match_name[*match];
222
223 switch (c) {
224 case '*':
225 /* Wildcard in @match_name means we've matched. */
226 return true;
227
228 case '\0':
229 /* @match_name has ended. Has @var_name too? */
230 return (*match == len);
231
232 default:
233 /*
234 * We've reached a non-wildcard char in @match_name.
235 * Continue only if there's an identical character in
236 * @var_name.
237 */
238 if (*match < len && c == var_name[*match])
239 continue;
240 return false;
241 }
242 }
243}
244
245bool
246efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
247 unsigned long data_size)
248{
249 int i;
250 unsigned long utf8_size;
251 u8 *utf8_name;
252
253 utf8_size = ucs2_utf8size(var_name);
254 utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL);
255 if (!utf8_name)
256 return false;
257
258 ucs2_as_utf8(utf8_name, var_name, utf8_size);
259 utf8_name[utf8_size] = '\0';
260
261 for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
262 const char *name = variable_validate[i].name;
263 int match = 0;
264
265 if (efi_guidcmp(vendor, variable_validate[i].vendor))
266 continue;
267
268 if (variable_matches(utf8_name, utf8_size+1, name, &match)) {
269 if (variable_validate[i].validate == NULL)
270 break;
271 kfree(utf8_name);
272 return variable_validate[i].validate(var_name, match,
273 data, data_size);
274 }
275 }
276 kfree(utf8_name);
277 return true;
278}
279EXPORT_SYMBOL_GPL(efivar_validate);
280
281bool
282efivar_variable_is_removable(efi_guid_t vendor, const char *var_name,
283 size_t len)
284{
285 int i;
286 bool found = false;
287 int match = 0;
288
289 /*
290 * Check if our variable is in the validated variables list
291 */
292 for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
293 if (efi_guidcmp(variable_validate[i].vendor, vendor))
294 continue;
295
296 if (variable_matches(var_name, len,
297 variable_validate[i].name, &match)) {
298 found = true;
299 break;
300 }
301 }
302
303 /*
304 * If it's in our list, it is removable.
305 */
306 return found;
307}
308EXPORT_SYMBOL_GPL(efivar_variable_is_removable);
309
310static efi_status_t
311check_var_size(u32 attributes, unsigned long size)
312{
313 const struct efivar_operations *fops = __efivars->ops;
314
315 if (!fops->query_variable_store)
316 return EFI_UNSUPPORTED;
317
318 return fops->query_variable_store(attributes, size, false);
319}
320
321static efi_status_t
322check_var_size_nonblocking(u32 attributes, unsigned long size)
323{
324 const struct efivar_operations *fops = __efivars->ops;
325
326 if (!fops->query_variable_store)
327 return EFI_UNSUPPORTED;
328
329 return fops->query_variable_store(attributes, size, true);
330}
331
332static int efi_status_to_err(efi_status_t status)
333{
334 int err;
335
336 switch (status) {
337 case EFI_SUCCESS:
338 err = 0;
339 break;
340 case EFI_INVALID_PARAMETER:
341 err = -EINVAL;
342 break;
343 case EFI_OUT_OF_RESOURCES:
344 err = -ENOSPC;
345 break;
346 case EFI_DEVICE_ERROR:
347 err = -EIO;
348 break;
349 case EFI_WRITE_PROTECTED:
350 err = -EROFS;
351 break;
352 case EFI_SECURITY_VIOLATION:
353 err = -EACCES;
354 break;
355 case EFI_NOT_FOUND:
356 err = -ENOENT;
357 break;
358 default:
359 err = -EINVAL;
360 }
361
362 return err;
363}
364
365static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
366 struct list_head *head)
367{
368 struct efivar_entry *entry, *n;
369 unsigned long strsize1, strsize2;
370 bool found = false;
371
372 strsize1 = ucs2_strsize(variable_name, 1024);
373 list_for_each_entry_safe(entry, n, head, list) {
374 strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
375 if (strsize1 == strsize2 &&
376 !memcmp(variable_name, &(entry->var.VariableName),
377 strsize2) &&
378 !efi_guidcmp(entry->var.VendorGuid,
379 *vendor)) {
380 found = true;
381 break;
382 }
383 }
384 return found;
385}
386
387/*
388 * Returns the size of variable_name, in bytes, including the
389 * terminating NULL character, or variable_name_size if no NULL
390 * character is found among the first variable_name_size bytes.
391 */
392static unsigned long var_name_strnsize(efi_char16_t *variable_name,
393 unsigned long variable_name_size)
394{
395 unsigned long len;
396 efi_char16_t c;
397
398 /*
399 * The variable name is, by definition, a NULL-terminated
400 * string, so make absolutely sure that variable_name_size is
401 * the value we expect it to be. If not, return the real size.
402 */
403 for (len = 2; len <= variable_name_size; len += sizeof(c)) {
404 c = variable_name[(len / sizeof(c)) - 1];
405 if (!c)
406 break;
407 }
408
409 return min(len, variable_name_size);
410}
411
412/*
413 * Print a warning when duplicate EFI variables are encountered and
414 * disable the sysfs workqueue since the firmware is buggy.
415 */
416static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
417 unsigned long len16)
418{
419 size_t i, len8 = len16 / sizeof(efi_char16_t);
420 char *str8;
421
422 /*
423 * Disable the workqueue since the algorithm it uses for
424 * detecting new variables won't work with this buggy
425 * implementation of GetNextVariableName().
426 */
427 efivar_wq_enabled = false;
428
429 str8 = kzalloc(len8, GFP_KERNEL);
430 if (!str8)
431 return;
432
433 for (i = 0; i < len8; i++)
434 str8[i] = str16[i];
435
436 printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
437 str8, vendor_guid);
438 kfree(str8);
439}
440
441/**
442 * efivar_init - build the initial list of EFI variables
443 * @func: callback function to invoke for every variable
444 * @data: function-specific data to pass to @func
445 * @atomic: do we need to execute the @func-loop atomically?
446 * @duplicates: error if we encounter duplicates on @head?
447 * @head: initialised head of variable list
448 *
449 * Get every EFI variable from the firmware and invoke @func. @func
450 * should call efivar_entry_add() to build the list of variables.
451 *
452 * Returns 0 on success, or a kernel error code on failure.
453 */
454int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
455 void *data, bool atomic, bool duplicates,
456 struct list_head *head)
457{
458 const struct efivar_operations *ops = __efivars->ops;
459 unsigned long variable_name_size = 1024;
460 efi_char16_t *variable_name;
461 efi_status_t status;
462 efi_guid_t vendor_guid;
463 int err = 0;
464
465 variable_name = kzalloc(variable_name_size, GFP_KERNEL);
466 if (!variable_name) {
467 printk(KERN_ERR "efivars: Memory allocation failed.\n");
468 return -ENOMEM;
469 }
470
471 spin_lock_irq(&__efivars->lock);
472
473 /*
474 * Per EFI spec, the maximum storage allocated for both
475 * the variable name and variable data is 1024 bytes.
476 */
477
478 do {
479 variable_name_size = 1024;
480
481 status = ops->get_next_variable(&variable_name_size,
482 variable_name,
483 &vendor_guid);
484 switch (status) {
485 case EFI_SUCCESS:
486 if (!atomic)
487 spin_unlock_irq(&__efivars->lock);
488
489 variable_name_size = var_name_strnsize(variable_name,
490 variable_name_size);
491
492 /*
493 * Some firmware implementations return the
494 * same variable name on multiple calls to
495 * get_next_variable(). Terminate the loop
496 * immediately as there is no guarantee that
497 * we'll ever see a different variable name,
498 * and may end up looping here forever.
499 */
500 if (duplicates &&
501 variable_is_present(variable_name, &vendor_guid, head)) {
502 dup_variable_bug(variable_name, &vendor_guid,
503 variable_name_size);
504 if (!atomic)
505 spin_lock_irq(&__efivars->lock);
506
507 status = EFI_NOT_FOUND;
508 break;
509 }
510
511 err = func(variable_name, vendor_guid, variable_name_size, data);
512 if (err)
513 status = EFI_NOT_FOUND;
514
515 if (!atomic)
516 spin_lock_irq(&__efivars->lock);
517
518 break;
519 case EFI_NOT_FOUND:
520 break;
521 default:
522 printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n",
523 status);
524 status = EFI_NOT_FOUND;
525 break;
526 }
527
528 } while (status != EFI_NOT_FOUND);
529
530 spin_unlock_irq(&__efivars->lock);
531
532 kfree(variable_name);
533
534 return err;
535}
536EXPORT_SYMBOL_GPL(efivar_init);
537
538/**
539 * efivar_entry_add - add entry to variable list
540 * @entry: entry to add to list
541 * @head: list head
542 */
543void efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
544{
545 spin_lock_irq(&__efivars->lock);
546 list_add(&entry->list, head);
547 spin_unlock_irq(&__efivars->lock);
548}
549EXPORT_SYMBOL_GPL(efivar_entry_add);
550
551/**
552 * efivar_entry_remove - remove entry from variable list
553 * @entry: entry to remove from list
554 */
555void efivar_entry_remove(struct efivar_entry *entry)
556{
557 spin_lock_irq(&__efivars->lock);
558 list_del(&entry->list);
559 spin_unlock_irq(&__efivars->lock);
560}
561EXPORT_SYMBOL_GPL(efivar_entry_remove);
562
563/*
564 * efivar_entry_list_del_unlock - remove entry from variable list
565 * @entry: entry to remove
566 *
567 * Remove @entry from the variable list and release the list lock.
568 *
569 * NOTE: slightly weird locking semantics here - we expect to be
570 * called with the efivars lock already held, and we release it before
571 * returning. This is because this function is usually called after
572 * set_variable() while the lock is still held.
573 */
574static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
575{
576 lockdep_assert_held(&__efivars->lock);
577
578 list_del(&entry->list);
579 spin_unlock_irq(&__efivars->lock);
580}
581
582/**
583 * __efivar_entry_delete - delete an EFI variable
584 * @entry: entry containing EFI variable to delete
585 *
586 * Delete the variable from the firmware but leave @entry on the
587 * variable list.
588 *
589 * This function differs from efivar_entry_delete() because it does
590 * not remove @entry from the variable list. Also, it is safe to be
591 * called from within a efivar_entry_iter_begin() and
592 * efivar_entry_iter_end() region, unlike efivar_entry_delete().
593 *
594 * Returns 0 on success, or a converted EFI status code if
595 * set_variable() fails.
596 */
597int __efivar_entry_delete(struct efivar_entry *entry)
598{
599 const struct efivar_operations *ops = __efivars->ops;
600 efi_status_t status;
601
602 lockdep_assert_held(&__efivars->lock);
603
604 status = ops->set_variable(entry->var.VariableName,
605 &entry->var.VendorGuid,
606 0, 0, NULL);
607
608 return efi_status_to_err(status);
609}
610EXPORT_SYMBOL_GPL(__efivar_entry_delete);
611
612/**
613 * efivar_entry_delete - delete variable and remove entry from list
614 * @entry: entry containing variable to delete
615 *
616 * Delete the variable from the firmware and remove @entry from the
617 * variable list. It is the caller's responsibility to free @entry
618 * once we return.
619 *
620 * Returns 0 on success, or a converted EFI status code if
621 * set_variable() fails.
622 */
623int efivar_entry_delete(struct efivar_entry *entry)
624{
625 const struct efivar_operations *ops = __efivars->ops;
626 efi_status_t status;
627
628 spin_lock_irq(&__efivars->lock);
629 status = ops->set_variable(entry->var.VariableName,
630 &entry->var.VendorGuid,
631 0, 0, NULL);
632 if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
633 spin_unlock_irq(&__efivars->lock);
634 return efi_status_to_err(status);
635 }
636
637 efivar_entry_list_del_unlock(entry);
638 return 0;
639}
640EXPORT_SYMBOL_GPL(efivar_entry_delete);
641
642/**
643 * efivar_entry_set - call set_variable()
644 * @entry: entry containing the EFI variable to write
645 * @attributes: variable attributes
646 * @size: size of @data buffer
647 * @data: buffer containing variable data
648 * @head: head of variable list
649 *
650 * Calls set_variable() for an EFI variable. If creating a new EFI
651 * variable, this function is usually followed by efivar_entry_add().
652 *
653 * Before writing the variable, the remaining EFI variable storage
654 * space is checked to ensure there is enough room available.
655 *
656 * If @head is not NULL a lookup is performed to determine whether
657 * the entry is already on the list.
658 *
659 * Returns 0 on success, -EEXIST if a lookup is performed and the entry
660 * already exists on the list, or a converted EFI status code if
661 * set_variable() fails.
662 */
663int efivar_entry_set(struct efivar_entry *entry, u32 attributes,
664 unsigned long size, void *data, struct list_head *head)
665{
666 const struct efivar_operations *ops = __efivars->ops;
667 efi_status_t status;
668 efi_char16_t *name = entry->var.VariableName;
669 efi_guid_t vendor = entry->var.VendorGuid;
670
671 spin_lock_irq(&__efivars->lock);
672
673 if (head && efivar_entry_find(name, vendor, head, false)) {
674 spin_unlock_irq(&__efivars->lock);
675 return -EEXIST;
676 }
677
678 status = check_var_size(attributes, size + ucs2_strsize(name, 1024));
679 if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
680 status = ops->set_variable(name, &vendor,
681 attributes, size, data);
682
683 spin_unlock_irq(&__efivars->lock);
684
685 return efi_status_to_err(status);
686
687}
688EXPORT_SYMBOL_GPL(efivar_entry_set);
689
690/*
691 * efivar_entry_set_nonblocking - call set_variable_nonblocking()
692 *
693 * This function is guaranteed to not block and is suitable for calling
694 * from crash/panic handlers.
695 *
696 * Crucially, this function will not block if it cannot acquire
697 * __efivars->lock. Instead, it returns -EBUSY.
698 */
699static int
700efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor,
701 u32 attributes, unsigned long size, void *data)
702{
703 const struct efivar_operations *ops = __efivars->ops;
704 unsigned long flags;
705 efi_status_t status;
706
707 if (!spin_trylock_irqsave(&__efivars->lock, flags))
708 return -EBUSY;
709
710 status = check_var_size_nonblocking(attributes,
711 size + ucs2_strsize(name, 1024));
712 if (status != EFI_SUCCESS) {
713 spin_unlock_irqrestore(&__efivars->lock, flags);
714 return -ENOSPC;
715 }
716
717 status = ops->set_variable_nonblocking(name, &vendor, attributes,
718 size, data);
719
720 spin_unlock_irqrestore(&__efivars->lock, flags);
721 return efi_status_to_err(status);
722}
723
724/**
725 * efivar_entry_set_safe - call set_variable() if enough space in firmware
726 * @name: buffer containing the variable name
727 * @vendor: variable vendor guid
728 * @attributes: variable attributes
729 * @block: can we block in this context?
730 * @size: size of @data buffer
731 * @data: buffer containing variable data
732 *
733 * Ensures there is enough free storage in the firmware for this variable, and
734 * if so, calls set_variable(). If creating a new EFI variable, this function
735 * is usually followed by efivar_entry_add().
736 *
737 * Returns 0 on success, -ENOSPC if the firmware does not have enough
738 * space for set_variable() to succeed, or a converted EFI status code
739 * if set_variable() fails.
740 */
741int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes,
742 bool block, unsigned long size, void *data)
743{
744 const struct efivar_operations *ops = __efivars->ops;
745 unsigned long flags;
746 efi_status_t status;
747
748 if (!ops->query_variable_store)
749 return -ENOSYS;
750
751 /*
752 * If the EFI variable backend provides a non-blocking
753 * ->set_variable() operation and we're in a context where we
754 * cannot block, then we need to use it to avoid live-locks,
755 * since the implication is that the regular ->set_variable()
756 * will block.
757 *
758 * If no ->set_variable_nonblocking() is provided then
759 * ->set_variable() is assumed to be non-blocking.
760 */
761 if (!block && ops->set_variable_nonblocking)
762 return efivar_entry_set_nonblocking(name, vendor, attributes,
763 size, data);
764
765 if (!block) {
766 if (!spin_trylock_irqsave(&__efivars->lock, flags))
767 return -EBUSY;
768 } else {
769 spin_lock_irqsave(&__efivars->lock, flags);
770 }
771
772 status = check_var_size(attributes, size + ucs2_strsize(name, 1024));
773 if (status != EFI_SUCCESS) {
774 spin_unlock_irqrestore(&__efivars->lock, flags);
775 return -ENOSPC;
776 }
777
778 status = ops->set_variable(name, &vendor, attributes, size, data);
779
780 spin_unlock_irqrestore(&__efivars->lock, flags);
781
782 return efi_status_to_err(status);
783}
784EXPORT_SYMBOL_GPL(efivar_entry_set_safe);
785
786/**
787 * efivar_entry_find - search for an entry
788 * @name: the EFI variable name
789 * @guid: the EFI variable vendor's guid
790 * @head: head of the variable list
791 * @remove: should we remove the entry from the list?
792 *
793 * Search for an entry on the variable list that has the EFI variable
794 * name @name and vendor guid @guid. If an entry is found on the list
795 * and @remove is true, the entry is removed from the list.
796 *
797 * The caller MUST call efivar_entry_iter_begin() and
798 * efivar_entry_iter_end() before and after the invocation of this
799 * function, respectively.
800 *
801 * Returns the entry if found on the list, %NULL otherwise.
802 */
803struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid,
804 struct list_head *head, bool remove)
805{
806 struct efivar_entry *entry, *n;
807 int strsize1, strsize2;
808 bool found = false;
809
810 lockdep_assert_held(&__efivars->lock);
811
812 list_for_each_entry_safe(entry, n, head, list) {
813 strsize1 = ucs2_strsize(name, 1024);
814 strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
815 if (strsize1 == strsize2 &&
816 !memcmp(name, &(entry->var.VariableName), strsize1) &&
817 !efi_guidcmp(guid, entry->var.VendorGuid)) {
818 found = true;
819 break;
820 }
821 }
822
823 if (!found)
824 return NULL;
825
826 if (remove) {
827 if (entry->scanning) {
828 /*
829 * The entry will be deleted
830 * after scanning is completed.
831 */
832 entry->deleting = true;
833 } else
834 list_del(&entry->list);
835 }
836
837 return entry;
838}
839EXPORT_SYMBOL_GPL(efivar_entry_find);
840
841/**
842 * efivar_entry_size - obtain the size of a variable
843 * @entry: entry for this variable
844 * @size: location to store the variable's size
845 */
846int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
847{
848 const struct efivar_operations *ops = __efivars->ops;
849 efi_status_t status;
850
851 *size = 0;
852
853 spin_lock_irq(&__efivars->lock);
854 status = ops->get_variable(entry->var.VariableName,
855 &entry->var.VendorGuid, NULL, size, NULL);
856 spin_unlock_irq(&__efivars->lock);
857
858 if (status != EFI_BUFFER_TOO_SMALL)
859 return efi_status_to_err(status);
860
861 return 0;
862}
863EXPORT_SYMBOL_GPL(efivar_entry_size);
864
865/**
866 * __efivar_entry_get - call get_variable()
867 * @entry: read data for this variable
868 * @attributes: variable attributes
869 * @size: size of @data buffer
870 * @data: buffer to store variable data
871 *
872 * The caller MUST call efivar_entry_iter_begin() and
873 * efivar_entry_iter_end() before and after the invocation of this
874 * function, respectively.
875 */
876int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
877 unsigned long *size, void *data)
878{
879 const struct efivar_operations *ops = __efivars->ops;
880 efi_status_t status;
881
882 lockdep_assert_held(&__efivars->lock);
883
884 status = ops->get_variable(entry->var.VariableName,
885 &entry->var.VendorGuid,
886 attributes, size, data);
887
888 return efi_status_to_err(status);
889}
890EXPORT_SYMBOL_GPL(__efivar_entry_get);
891
892/**
893 * efivar_entry_get - call get_variable()
894 * @entry: read data for this variable
895 * @attributes: variable attributes
896 * @size: size of @data buffer
897 * @data: buffer to store variable data
898 */
899int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
900 unsigned long *size, void *data)
901{
902 const struct efivar_operations *ops = __efivars->ops;
903 efi_status_t status;
904
905 spin_lock_irq(&__efivars->lock);
906 status = ops->get_variable(entry->var.VariableName,
907 &entry->var.VendorGuid,
908 attributes, size, data);
909 spin_unlock_irq(&__efivars->lock);
910
911 return efi_status_to_err(status);
912}
913EXPORT_SYMBOL_GPL(efivar_entry_get);
914
915/**
916 * efivar_entry_set_get_size - call set_variable() and get new size (atomic)
917 * @entry: entry containing variable to set and get
918 * @attributes: attributes of variable to be written
919 * @size: size of data buffer
920 * @data: buffer containing data to write
921 * @set: did the set_variable() call succeed?
922 *
923 * This is a pretty special (complex) function. See efivarfs_file_write().
924 *
925 * Atomically call set_variable() for @entry and if the call is
926 * successful, return the new size of the variable from get_variable()
927 * in @size. The success of set_variable() is indicated by @set.
928 *
929 * Returns 0 on success, -EINVAL if the variable data is invalid,
930 * -ENOSPC if the firmware does not have enough available space, or a
931 * converted EFI status code if either of set_variable() or
932 * get_variable() fail.
933 *
934 * If the EFI variable does not exist when calling set_variable()
935 * (EFI_NOT_FOUND), @entry is removed from the variable list.
936 */
937int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
938 unsigned long *size, void *data, bool *set)
939{
940 const struct efivar_operations *ops = __efivars->ops;
941 efi_char16_t *name = entry->var.VariableName;
942 efi_guid_t *vendor = &entry->var.VendorGuid;
943 efi_status_t status;
944 int err;
945
946 *set = false;
947
948 if (efivar_validate(*vendor, name, data, *size) == false)
949 return -EINVAL;
950
951 /*
952 * The lock here protects the get_variable call, the conditional
953 * set_variable call, and removal of the variable from the efivars
954 * list (in the case of an authenticated delete).
955 */
956 spin_lock_irq(&__efivars->lock);
957
958 /*
959 * Ensure that the available space hasn't shrunk below the safe level
960 */
961 status = check_var_size(attributes, *size + ucs2_strsize(name, 1024));
962 if (status != EFI_SUCCESS) {
963 if (status != EFI_UNSUPPORTED) {
964 err = efi_status_to_err(status);
965 goto out;
966 }
967
968 if (*size > 65536) {
969 err = -ENOSPC;
970 goto out;
971 }
972 }
973
974 status = ops->set_variable(name, vendor, attributes, *size, data);
975 if (status != EFI_SUCCESS) {
976 err = efi_status_to_err(status);
977 goto out;
978 }
979
980 *set = true;
981
982 /*
983 * Writing to the variable may have caused a change in size (which
984 * could either be an append or an overwrite), or the variable to be
985 * deleted. Perform a GetVariable() so we can tell what actually
986 * happened.
987 */
988 *size = 0;
989 status = ops->get_variable(entry->var.VariableName,
990 &entry->var.VendorGuid,
991 NULL, size, NULL);
992
993 if (status == EFI_NOT_FOUND)
994 efivar_entry_list_del_unlock(entry);
995 else
996 spin_unlock_irq(&__efivars->lock);
997
998 if (status && status != EFI_BUFFER_TOO_SMALL)
999 return efi_status_to_err(status);
1000
1001 return 0;
1002
1003out:
1004 spin_unlock_irq(&__efivars->lock);
1005 return err;
1006
1007}
1008EXPORT_SYMBOL_GPL(efivar_entry_set_get_size);
1009
1010/**
1011 * efivar_entry_iter_begin - begin iterating the variable list
1012 *
1013 * Lock the variable list to prevent entry insertion and removal until
1014 * efivar_entry_iter_end() is called. This function is usually used in
1015 * conjunction with __efivar_entry_iter() or efivar_entry_iter().
1016 */
1017void efivar_entry_iter_begin(void)
1018{
1019 spin_lock_irq(&__efivars->lock);
1020}
1021EXPORT_SYMBOL_GPL(efivar_entry_iter_begin);
1022
1023/**
1024 * efivar_entry_iter_end - finish iterating the variable list
1025 *
1026 * Unlock the variable list and allow modifications to the list again.
1027 */
1028void efivar_entry_iter_end(void)
1029{
1030 spin_unlock_irq(&__efivars->lock);
1031}
1032EXPORT_SYMBOL_GPL(efivar_entry_iter_end);
1033
1034/**
1035 * __efivar_entry_iter - iterate over variable list
1036 * @func: callback function
1037 * @head: head of the variable list
1038 * @data: function-specific data to pass to callback
1039 * @prev: entry to begin iterating from
1040 *
1041 * Iterate over the list of EFI variables and call @func with every
1042 * entry on the list. It is safe for @func to remove entries in the
1043 * list via efivar_entry_delete().
1044 *
1045 * You MUST call efivar_enter_iter_begin() before this function, and
1046 * efivar_entry_iter_end() afterwards.
1047 *
1048 * It is possible to begin iteration from an arbitrary entry within
1049 * the list by passing @prev. @prev is updated on return to point to
1050 * the last entry passed to @func. To begin iterating from the
1051 * beginning of the list @prev must be %NULL.
1052 *
1053 * The restrictions for @func are the same as documented for
1054 * efivar_entry_iter().
1055 */
1056int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
1057 struct list_head *head, void *data,
1058 struct efivar_entry **prev)
1059{
1060 struct efivar_entry *entry, *n;
1061 int err = 0;
1062
1063 if (!prev || !*prev) {
1064 list_for_each_entry_safe(entry, n, head, list) {
1065 err = func(entry, data);
1066 if (err)
1067 break;
1068 }
1069
1070 if (prev)
1071 *prev = entry;
1072
1073 return err;
1074 }
1075
1076
1077 list_for_each_entry_safe_continue((*prev), n, head, list) {
1078 err = func(*prev, data);
1079 if (err)
1080 break;
1081 }
1082
1083 return err;
1084}
1085EXPORT_SYMBOL_GPL(__efivar_entry_iter);
1086
1087/**
1088 * efivar_entry_iter - iterate over variable list
1089 * @func: callback function
1090 * @head: head of variable list
1091 * @data: function-specific data to pass to callback
1092 *
1093 * Iterate over the list of EFI variables and call @func with every
1094 * entry on the list. It is safe for @func to remove entries in the
1095 * list via efivar_entry_delete() while iterating.
1096 *
1097 * Some notes for the callback function:
1098 * - a non-zero return value indicates an error and terminates the loop
1099 * - @func is called from atomic context
1100 */
1101int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
1102 struct list_head *head, void *data)
1103{
1104 int err = 0;
1105
1106 efivar_entry_iter_begin();
1107 err = __efivar_entry_iter(func, head, data, NULL);
1108 efivar_entry_iter_end();
1109
1110 return err;
1111}
1112EXPORT_SYMBOL_GPL(efivar_entry_iter);
1113
1114/**
1115 * efivars_kobject - get the kobject for the registered efivars
1116 *
1117 * If efivars_register() has not been called we return NULL,
1118 * otherwise return the kobject used at registration time.
1119 */
1120struct kobject *efivars_kobject(void)
1121{
1122 if (!__efivars)
1123 return NULL;
1124
1125 return __efivars->kobject;
1126}
1127EXPORT_SYMBOL_GPL(efivars_kobject);
1128
1129/**
1130 * efivar_run_worker - schedule the efivar worker thread
1131 */
1132void efivar_run_worker(void)
1133{
1134 if (efivar_wq_enabled)
1135 schedule_work(&efivar_work);
1136}
1137EXPORT_SYMBOL_GPL(efivar_run_worker);
1138
1139/**
1140 * efivars_register - register an efivars
1141 * @efivars: efivars to register
1142 * @ops: efivars operations
1143 * @kobject: @efivars-specific kobject
1144 *
1145 * Only a single efivars can be registered at any time.
1146 */
1147int efivars_register(struct efivars *efivars,
1148 const struct efivar_operations *ops,
1149 struct kobject *kobject)
1150{
1151 spin_lock_init(&efivars->lock);
1152 efivars->ops = ops;
1153 efivars->kobject = kobject;
1154
1155 __efivars = efivars;
1156
1157 return 0;
1158}
1159EXPORT_SYMBOL_GPL(efivars_register);
1160
1161/**
1162 * efivars_unregister - unregister an efivars
1163 * @efivars: efivars to unregister
1164 *
1165 * The caller must have already removed every entry from the list,
1166 * failure to do so is an error.
1167 */
1168int efivars_unregister(struct efivars *efivars)
1169{
1170 int rv;
1171
1172 if (!__efivars) {
1173 printk(KERN_ERR "efivars not registered\n");
1174 rv = -EINVAL;
1175 goto out;
1176 }
1177
1178 if (__efivars != efivars) {
1179 rv = -EINVAL;
1180 goto out;
1181 }
1182
1183 __efivars = NULL;
1184
1185 rv = 0;
1186out:
1187 return rv;
1188}
1189EXPORT_SYMBOL_GPL(efivars_unregister);