12d82e622SArd Biesheuvel // SPDX-License-Identifier: GPL-2.0+
22d82e622SArd Biesheuvel /*
32d82e622SArd Biesheuvel * Originally from efivars.c
42d82e622SArd Biesheuvel *
52d82e622SArd Biesheuvel * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com>
62d82e622SArd Biesheuvel * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com>
72d82e622SArd Biesheuvel */
82d82e622SArd Biesheuvel
92d82e622SArd Biesheuvel #include <linux/capability.h>
102d82e622SArd Biesheuvel #include <linux/types.h>
112d82e622SArd Biesheuvel #include <linux/errno.h>
122d82e622SArd Biesheuvel #include <linux/init.h>
132d82e622SArd Biesheuvel #include <linux/mm.h>
142d82e622SArd Biesheuvel #include <linux/module.h>
152d82e622SArd Biesheuvel #include <linux/string.h>
162d82e622SArd Biesheuvel #include <linux/smp.h>
172d82e622SArd Biesheuvel #include <linux/efi.h>
182d82e622SArd Biesheuvel #include <linux/device.h>
192d82e622SArd Biesheuvel #include <linux/slab.h>
202d82e622SArd Biesheuvel #include <linux/ctype.h>
212d82e622SArd Biesheuvel #include <linux/ucs2_string.h>
222d82e622SArd Biesheuvel
232d82e622SArd Biesheuvel #include "internal.h"
242d82e622SArd Biesheuvel
252d82e622SArd Biesheuvel MODULE_IMPORT_NS(EFIVAR);
262d82e622SArd Biesheuvel
272d82e622SArd Biesheuvel static bool
validate_device_path(efi_char16_t * var_name,int match,u8 * buffer,unsigned long len)282d82e622SArd Biesheuvel validate_device_path(efi_char16_t *var_name, int match, u8 *buffer,
292d82e622SArd Biesheuvel unsigned long len)
302d82e622SArd Biesheuvel {
312d82e622SArd Biesheuvel struct efi_generic_dev_path *node;
322d82e622SArd Biesheuvel int offset = 0;
332d82e622SArd Biesheuvel
342d82e622SArd Biesheuvel node = (struct efi_generic_dev_path *)buffer;
352d82e622SArd Biesheuvel
362d82e622SArd Biesheuvel if (len < sizeof(*node))
372d82e622SArd Biesheuvel return false;
382d82e622SArd Biesheuvel
392d82e622SArd Biesheuvel while (offset <= len - sizeof(*node) &&
402d82e622SArd Biesheuvel node->length >= sizeof(*node) &&
412d82e622SArd Biesheuvel node->length <= len - offset) {
422d82e622SArd Biesheuvel offset += node->length;
432d82e622SArd Biesheuvel
442d82e622SArd Biesheuvel if ((node->type == EFI_DEV_END_PATH ||
452d82e622SArd Biesheuvel node->type == EFI_DEV_END_PATH2) &&
462d82e622SArd Biesheuvel node->sub_type == EFI_DEV_END_ENTIRE)
472d82e622SArd Biesheuvel return true;
482d82e622SArd Biesheuvel
492d82e622SArd Biesheuvel node = (struct efi_generic_dev_path *)(buffer + offset);
502d82e622SArd Biesheuvel }
512d82e622SArd Biesheuvel
522d82e622SArd Biesheuvel /*
532d82e622SArd Biesheuvel * If we're here then either node->length pointed past the end
542d82e622SArd Biesheuvel * of the buffer or we reached the end of the buffer without
552d82e622SArd Biesheuvel * finding a device path end node.
562d82e622SArd Biesheuvel */
572d82e622SArd Biesheuvel return false;
582d82e622SArd Biesheuvel }
592d82e622SArd Biesheuvel
602d82e622SArd Biesheuvel static bool
validate_boot_order(efi_char16_t * var_name,int match,u8 * buffer,unsigned long len)612d82e622SArd Biesheuvel validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer,
622d82e622SArd Biesheuvel unsigned long len)
632d82e622SArd Biesheuvel {
642d82e622SArd Biesheuvel /* An array of 16-bit integers */
652d82e622SArd Biesheuvel if ((len % 2) != 0)
662d82e622SArd Biesheuvel return false;
672d82e622SArd Biesheuvel
682d82e622SArd Biesheuvel return true;
692d82e622SArd Biesheuvel }
702d82e622SArd Biesheuvel
712d82e622SArd Biesheuvel static bool
validate_load_option(efi_char16_t * var_name,int match,u8 * buffer,unsigned long len)722d82e622SArd Biesheuvel validate_load_option(efi_char16_t *var_name, int match, u8 *buffer,
732d82e622SArd Biesheuvel unsigned long len)
742d82e622SArd Biesheuvel {
752d82e622SArd Biesheuvel u16 filepathlength;
762d82e622SArd Biesheuvel int i, desclength = 0, namelen;
772d82e622SArd Biesheuvel
782d82e622SArd Biesheuvel namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN);
792d82e622SArd Biesheuvel
802d82e622SArd Biesheuvel /* Either "Boot" or "Driver" followed by four digits of hex */
812d82e622SArd Biesheuvel for (i = match; i < match+4; i++) {
822d82e622SArd Biesheuvel if (var_name[i] > 127 ||
832d82e622SArd Biesheuvel hex_to_bin(var_name[i] & 0xff) < 0)
842d82e622SArd Biesheuvel return true;
852d82e622SArd Biesheuvel }
862d82e622SArd Biesheuvel
872d82e622SArd Biesheuvel /* Reject it if there's 4 digits of hex and then further content */
882d82e622SArd Biesheuvel if (namelen > match + 4)
892d82e622SArd Biesheuvel return false;
902d82e622SArd Biesheuvel
912d82e622SArd Biesheuvel /* A valid entry must be at least 8 bytes */
922d82e622SArd Biesheuvel if (len < 8)
932d82e622SArd Biesheuvel return false;
942d82e622SArd Biesheuvel
952d82e622SArd Biesheuvel filepathlength = buffer[4] | buffer[5] << 8;
962d82e622SArd Biesheuvel
972d82e622SArd Biesheuvel /*
982d82e622SArd Biesheuvel * There's no stored length for the description, so it has to be
992d82e622SArd Biesheuvel * found by hand
1002d82e622SArd Biesheuvel */
1012d82e622SArd Biesheuvel desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2;
1022d82e622SArd Biesheuvel
1032d82e622SArd Biesheuvel /* Each boot entry must have a descriptor */
1042d82e622SArd Biesheuvel if (!desclength)
1052d82e622SArd Biesheuvel return false;
1062d82e622SArd Biesheuvel
1072d82e622SArd Biesheuvel /*
1082d82e622SArd Biesheuvel * If the sum of the length of the description, the claimed filepath
1092d82e622SArd Biesheuvel * length and the original header are greater than the length of the
1102d82e622SArd Biesheuvel * variable, it's malformed
1112d82e622SArd Biesheuvel */
1122d82e622SArd Biesheuvel if ((desclength + filepathlength + 6) > len)
1132d82e622SArd Biesheuvel return false;
1142d82e622SArd Biesheuvel
1152d82e622SArd Biesheuvel /*
1162d82e622SArd Biesheuvel * And, finally, check the filepath
1172d82e622SArd Biesheuvel */
1182d82e622SArd Biesheuvel return validate_device_path(var_name, match, buffer + desclength + 6,
1192d82e622SArd Biesheuvel filepathlength);
1202d82e622SArd Biesheuvel }
1212d82e622SArd Biesheuvel
1222d82e622SArd Biesheuvel static bool
validate_uint16(efi_char16_t * var_name,int match,u8 * buffer,unsigned long len)1232d82e622SArd Biesheuvel validate_uint16(efi_char16_t *var_name, int match, u8 *buffer,
1242d82e622SArd Biesheuvel unsigned long len)
1252d82e622SArd Biesheuvel {
1262d82e622SArd Biesheuvel /* A single 16-bit integer */
1272d82e622SArd Biesheuvel if (len != 2)
1282d82e622SArd Biesheuvel return false;
1292d82e622SArd Biesheuvel
1302d82e622SArd Biesheuvel return true;
1312d82e622SArd Biesheuvel }
1322d82e622SArd Biesheuvel
1332d82e622SArd Biesheuvel static bool
validate_ascii_string(efi_char16_t * var_name,int match,u8 * buffer,unsigned long len)1342d82e622SArd Biesheuvel validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer,
1352d82e622SArd Biesheuvel unsigned long len)
1362d82e622SArd Biesheuvel {
1372d82e622SArd Biesheuvel int i;
1382d82e622SArd Biesheuvel
1392d82e622SArd Biesheuvel for (i = 0; i < len; i++) {
1402d82e622SArd Biesheuvel if (buffer[i] > 127)
1412d82e622SArd Biesheuvel return false;
1422d82e622SArd Biesheuvel
1432d82e622SArd Biesheuvel if (buffer[i] == 0)
1442d82e622SArd Biesheuvel return true;
1452d82e622SArd Biesheuvel }
1462d82e622SArd Biesheuvel
1472d82e622SArd Biesheuvel return false;
1482d82e622SArd Biesheuvel }
1492d82e622SArd Biesheuvel
1502d82e622SArd Biesheuvel struct variable_validate {
1512d82e622SArd Biesheuvel efi_guid_t vendor;
1522d82e622SArd Biesheuvel char *name;
1532d82e622SArd Biesheuvel bool (*validate)(efi_char16_t *var_name, int match, u8 *data,
1542d82e622SArd Biesheuvel unsigned long len);
1552d82e622SArd Biesheuvel };
1562d82e622SArd Biesheuvel
1572d82e622SArd Biesheuvel /*
1582d82e622SArd Biesheuvel * This is the list of variables we need to validate, as well as the
1592d82e622SArd Biesheuvel * whitelist for what we think is safe not to default to immutable.
1602d82e622SArd Biesheuvel *
1612d82e622SArd Biesheuvel * If it has a validate() method that's not NULL, it'll go into the
1622d82e622SArd Biesheuvel * validation routine. If not, it is assumed valid, but still used for
1632d82e622SArd Biesheuvel * whitelisting.
1642d82e622SArd Biesheuvel *
1652d82e622SArd Biesheuvel * Note that it's sorted by {vendor,name}, but globbed names must come after
1662d82e622SArd Biesheuvel * any other name with the same prefix.
1672d82e622SArd Biesheuvel */
1682d82e622SArd Biesheuvel static const struct variable_validate variable_validate[] = {
1692d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 },
1702d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order },
1712d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option },
1722d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order },
1732d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option },
1742d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path },
1752d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path },
1762d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path },
1772d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path },
1782d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path },
1792d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path },
1802d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string },
1812d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL },
1822d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string },
1832d82e622SArd Biesheuvel { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 },
1842d82e622SArd Biesheuvel { LINUX_EFI_CRASH_GUID, "*", NULL },
1852d82e622SArd Biesheuvel { NULL_GUID, "", NULL },
1862d82e622SArd Biesheuvel };
1872d82e622SArd Biesheuvel
1882d82e622SArd Biesheuvel /*
1892d82e622SArd Biesheuvel * Check if @var_name matches the pattern given in @match_name.
1902d82e622SArd Biesheuvel *
1912d82e622SArd Biesheuvel * @var_name: an array of @len non-NUL characters.
1922d82e622SArd Biesheuvel * @match_name: a NUL-terminated pattern string, optionally ending in "*". A
1932d82e622SArd Biesheuvel * final "*" character matches any trailing characters @var_name,
1942d82e622SArd Biesheuvel * including the case when there are none left in @var_name.
1952d82e622SArd Biesheuvel * @match: on output, the number of non-wildcard characters in @match_name
1962d82e622SArd Biesheuvel * that @var_name matches, regardless of the return value.
1972d82e622SArd Biesheuvel * @return: whether @var_name fully matches @match_name.
1982d82e622SArd Biesheuvel */
1992d82e622SArd Biesheuvel static bool
variable_matches(const char * var_name,size_t len,const char * match_name,int * match)2002d82e622SArd Biesheuvel variable_matches(const char *var_name, size_t len, const char *match_name,
2012d82e622SArd Biesheuvel int *match)
2022d82e622SArd Biesheuvel {
2032d82e622SArd Biesheuvel for (*match = 0; ; (*match)++) {
2042d82e622SArd Biesheuvel char c = match_name[*match];
2052d82e622SArd Biesheuvel
2062d82e622SArd Biesheuvel switch (c) {
2072d82e622SArd Biesheuvel case '*':
2082d82e622SArd Biesheuvel /* Wildcard in @match_name means we've matched. */
2092d82e622SArd Biesheuvel return true;
2102d82e622SArd Biesheuvel
2112d82e622SArd Biesheuvel case '\0':
2122d82e622SArd Biesheuvel /* @match_name has ended. Has @var_name too? */
2132d82e622SArd Biesheuvel return (*match == len);
2142d82e622SArd Biesheuvel
2152d82e622SArd Biesheuvel default:
2162d82e622SArd Biesheuvel /*
2172d82e622SArd Biesheuvel * We've reached a non-wildcard char in @match_name.
2182d82e622SArd Biesheuvel * Continue only if there's an identical character in
2192d82e622SArd Biesheuvel * @var_name.
2202d82e622SArd Biesheuvel */
2212d82e622SArd Biesheuvel if (*match < len && c == var_name[*match])
2222d82e622SArd Biesheuvel continue;
2232d82e622SArd Biesheuvel return false;
2242d82e622SArd Biesheuvel }
2252d82e622SArd Biesheuvel }
2262d82e622SArd Biesheuvel }
2272d82e622SArd Biesheuvel
2282d82e622SArd Biesheuvel bool
efivar_validate(efi_guid_t vendor,efi_char16_t * var_name,u8 * data,unsigned long data_size)2292d82e622SArd Biesheuvel efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
2302d82e622SArd Biesheuvel unsigned long data_size)
2312d82e622SArd Biesheuvel {
2322d82e622SArd Biesheuvel int i;
2332d82e622SArd Biesheuvel unsigned long utf8_size;
2342d82e622SArd Biesheuvel u8 *utf8_name;
2352d82e622SArd Biesheuvel
2362d82e622SArd Biesheuvel utf8_size = ucs2_utf8size(var_name);
2372d82e622SArd Biesheuvel utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL);
2382d82e622SArd Biesheuvel if (!utf8_name)
2392d82e622SArd Biesheuvel return false;
2402d82e622SArd Biesheuvel
2412d82e622SArd Biesheuvel ucs2_as_utf8(utf8_name, var_name, utf8_size);
2422d82e622SArd Biesheuvel utf8_name[utf8_size] = '\0';
2432d82e622SArd Biesheuvel
2442d82e622SArd Biesheuvel for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
2452d82e622SArd Biesheuvel const char *name = variable_validate[i].name;
2462d82e622SArd Biesheuvel int match = 0;
2472d82e622SArd Biesheuvel
2482d82e622SArd Biesheuvel if (efi_guidcmp(vendor, variable_validate[i].vendor))
2492d82e622SArd Biesheuvel continue;
2502d82e622SArd Biesheuvel
2512d82e622SArd Biesheuvel if (variable_matches(utf8_name, utf8_size+1, name, &match)) {
2522d82e622SArd Biesheuvel if (variable_validate[i].validate == NULL)
2532d82e622SArd Biesheuvel break;
2542d82e622SArd Biesheuvel kfree(utf8_name);
2552d82e622SArd Biesheuvel return variable_validate[i].validate(var_name, match,
2562d82e622SArd Biesheuvel data, data_size);
2572d82e622SArd Biesheuvel }
2582d82e622SArd Biesheuvel }
2592d82e622SArd Biesheuvel kfree(utf8_name);
2602d82e622SArd Biesheuvel return true;
2612d82e622SArd Biesheuvel }
2622d82e622SArd Biesheuvel
2632d82e622SArd Biesheuvel bool
efivar_variable_is_removable(efi_guid_t vendor,const char * var_name,size_t len)2642d82e622SArd Biesheuvel efivar_variable_is_removable(efi_guid_t vendor, const char *var_name,
2652d82e622SArd Biesheuvel size_t len)
2662d82e622SArd Biesheuvel {
2672d82e622SArd Biesheuvel int i;
2682d82e622SArd Biesheuvel bool found = false;
2692d82e622SArd Biesheuvel int match = 0;
2702d82e622SArd Biesheuvel
2712d82e622SArd Biesheuvel /*
2722d82e622SArd Biesheuvel * Check if our variable is in the validated variables list
2732d82e622SArd Biesheuvel */
2742d82e622SArd Biesheuvel for (i = 0; variable_validate[i].name[0] != '\0'; i++) {
2752d82e622SArd Biesheuvel if (efi_guidcmp(variable_validate[i].vendor, vendor))
2762d82e622SArd Biesheuvel continue;
2772d82e622SArd Biesheuvel
2782d82e622SArd Biesheuvel if (variable_matches(var_name, len,
2792d82e622SArd Biesheuvel variable_validate[i].name, &match)) {
2802d82e622SArd Biesheuvel found = true;
2812d82e622SArd Biesheuvel break;
2822d82e622SArd Biesheuvel }
2832d82e622SArd Biesheuvel }
2842d82e622SArd Biesheuvel
2852d82e622SArd Biesheuvel /*
2862d82e622SArd Biesheuvel * If it's in our list, it is removable.
2872d82e622SArd Biesheuvel */
2882d82e622SArd Biesheuvel return found;
2892d82e622SArd Biesheuvel }
2902d82e622SArd Biesheuvel
variable_is_present(efi_char16_t * variable_name,efi_guid_t * vendor,struct list_head * head)2912d82e622SArd Biesheuvel static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
2922d82e622SArd Biesheuvel struct list_head *head)
2932d82e622SArd Biesheuvel {
2942d82e622SArd Biesheuvel struct efivar_entry *entry, *n;
2952d82e622SArd Biesheuvel unsigned long strsize1, strsize2;
2962d82e622SArd Biesheuvel bool found = false;
2972d82e622SArd Biesheuvel
2982d82e622SArd Biesheuvel strsize1 = ucs2_strsize(variable_name, 1024);
2992d82e622SArd Biesheuvel list_for_each_entry_safe(entry, n, head, list) {
3002d82e622SArd Biesheuvel strsize2 = ucs2_strsize(entry->var.VariableName, 1024);
3012d82e622SArd Biesheuvel if (strsize1 == strsize2 &&
3022d82e622SArd Biesheuvel !memcmp(variable_name, &(entry->var.VariableName),
3032d82e622SArd Biesheuvel strsize2) &&
3042d82e622SArd Biesheuvel !efi_guidcmp(entry->var.VendorGuid,
3052d82e622SArd Biesheuvel *vendor)) {
3062d82e622SArd Biesheuvel found = true;
3072d82e622SArd Biesheuvel break;
3082d82e622SArd Biesheuvel }
3092d82e622SArd Biesheuvel }
3102d82e622SArd Biesheuvel return found;
3112d82e622SArd Biesheuvel }
3122d82e622SArd Biesheuvel
3132d82e622SArd Biesheuvel /*
3142d82e622SArd Biesheuvel * Returns the size of variable_name, in bytes, including the
3152d82e622SArd Biesheuvel * terminating NULL character, or variable_name_size if no NULL
3162d82e622SArd Biesheuvel * character is found among the first variable_name_size bytes.
3172d82e622SArd Biesheuvel */
var_name_strnsize(efi_char16_t * variable_name,unsigned long variable_name_size)3182d82e622SArd Biesheuvel static unsigned long var_name_strnsize(efi_char16_t *variable_name,
3192d82e622SArd Biesheuvel unsigned long variable_name_size)
3202d82e622SArd Biesheuvel {
3212d82e622SArd Biesheuvel unsigned long len;
3222d82e622SArd Biesheuvel efi_char16_t c;
3232d82e622SArd Biesheuvel
3242d82e622SArd Biesheuvel /*
3252d82e622SArd Biesheuvel * The variable name is, by definition, a NULL-terminated
3262d82e622SArd Biesheuvel * string, so make absolutely sure that variable_name_size is
3272d82e622SArd Biesheuvel * the value we expect it to be. If not, return the real size.
3282d82e622SArd Biesheuvel */
3292d82e622SArd Biesheuvel for (len = 2; len <= variable_name_size; len += sizeof(c)) {
3302d82e622SArd Biesheuvel c = variable_name[(len / sizeof(c)) - 1];
3312d82e622SArd Biesheuvel if (!c)
3322d82e622SArd Biesheuvel break;
3332d82e622SArd Biesheuvel }
3342d82e622SArd Biesheuvel
3352d82e622SArd Biesheuvel return min(len, variable_name_size);
3362d82e622SArd Biesheuvel }
3372d82e622SArd Biesheuvel
3382d82e622SArd Biesheuvel /*
3392d82e622SArd Biesheuvel * Print a warning when duplicate EFI variables are encountered and
3402d82e622SArd Biesheuvel * disable the sysfs workqueue since the firmware is buggy.
3412d82e622SArd Biesheuvel */
dup_variable_bug(efi_char16_t * str16,efi_guid_t * vendor_guid,unsigned long len16)3422d82e622SArd Biesheuvel static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
3432d82e622SArd Biesheuvel unsigned long len16)
3442d82e622SArd Biesheuvel {
3452d82e622SArd Biesheuvel size_t i, len8 = len16 / sizeof(efi_char16_t);
3462d82e622SArd Biesheuvel char *str8;
3472d82e622SArd Biesheuvel
3482d82e622SArd Biesheuvel str8 = kzalloc(len8, GFP_KERNEL);
3492d82e622SArd Biesheuvel if (!str8)
3502d82e622SArd Biesheuvel return;
3512d82e622SArd Biesheuvel
3522d82e622SArd Biesheuvel for (i = 0; i < len8; i++)
3532d82e622SArd Biesheuvel str8[i] = str16[i];
3542d82e622SArd Biesheuvel
3552d82e622SArd Biesheuvel printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
3562d82e622SArd Biesheuvel str8, vendor_guid);
3572d82e622SArd Biesheuvel kfree(str8);
3582d82e622SArd Biesheuvel }
3592d82e622SArd Biesheuvel
3602d82e622SArd Biesheuvel /**
3612d82e622SArd Biesheuvel * efivar_init - build the initial list of EFI variables
3622d82e622SArd Biesheuvel * @func: callback function to invoke for every variable
3632d82e622SArd Biesheuvel * @data: function-specific data to pass to @func
3642d82e622SArd Biesheuvel * @duplicates: error if we encounter duplicates on @head?
3652d82e622SArd Biesheuvel * @head: initialised head of variable list
3662d82e622SArd Biesheuvel *
3672d82e622SArd Biesheuvel * Get every EFI variable from the firmware and invoke @func. @func
3682d82e622SArd Biesheuvel * should call efivar_entry_add() to build the list of variables.
3692d82e622SArd Biesheuvel *
3702d82e622SArd Biesheuvel * Returns 0 on success, or a kernel error code on failure.
3712d82e622SArd Biesheuvel */
efivar_init(int (* func)(efi_char16_t *,efi_guid_t,unsigned long,void *),void * data,bool duplicates,struct list_head * head)3722d82e622SArd Biesheuvel int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
3732d82e622SArd Biesheuvel void *data, bool duplicates, struct list_head *head)
3742d82e622SArd Biesheuvel {
375*71da10e6STim Schumacher unsigned long variable_name_size = 512;
3762d82e622SArd Biesheuvel efi_char16_t *variable_name;
3772d82e622SArd Biesheuvel efi_status_t status;
3782d82e622SArd Biesheuvel efi_guid_t vendor_guid;
3792d82e622SArd Biesheuvel int err = 0;
3802d82e622SArd Biesheuvel
3812d82e622SArd Biesheuvel variable_name = kzalloc(variable_name_size, GFP_KERNEL);
3822d82e622SArd Biesheuvel if (!variable_name) {
3832d82e622SArd Biesheuvel printk(KERN_ERR "efivars: Memory allocation failed.\n");
3842d82e622SArd Biesheuvel return -ENOMEM;
3852d82e622SArd Biesheuvel }
3862d82e622SArd Biesheuvel
3872d82e622SArd Biesheuvel err = efivar_lock();
3882d82e622SArd Biesheuvel if (err)
3892d82e622SArd Biesheuvel goto free;
3902d82e622SArd Biesheuvel
3912d82e622SArd Biesheuvel /*
392*71da10e6STim Schumacher * A small set of old UEFI implementations reject sizes
393*71da10e6STim Schumacher * above a certain threshold, the lowest seen in the wild
394*71da10e6STim Schumacher * is 512.
3952d82e622SArd Biesheuvel */
3962d82e622SArd Biesheuvel
3972d82e622SArd Biesheuvel do {
398*71da10e6STim Schumacher variable_name_size = 512;
3992d82e622SArd Biesheuvel
4002d82e622SArd Biesheuvel status = efivar_get_next_variable(&variable_name_size,
4012d82e622SArd Biesheuvel variable_name,
4022d82e622SArd Biesheuvel &vendor_guid);
4032d82e622SArd Biesheuvel switch (status) {
4042d82e622SArd Biesheuvel case EFI_SUCCESS:
4052d82e622SArd Biesheuvel variable_name_size = var_name_strnsize(variable_name,
4062d82e622SArd Biesheuvel variable_name_size);
4072d82e622SArd Biesheuvel
4082d82e622SArd Biesheuvel /*
4092d82e622SArd Biesheuvel * Some firmware implementations return the
4102d82e622SArd Biesheuvel * same variable name on multiple calls to
4112d82e622SArd Biesheuvel * get_next_variable(). Terminate the loop
4122d82e622SArd Biesheuvel * immediately as there is no guarantee that
4132d82e622SArd Biesheuvel * we'll ever see a different variable name,
4142d82e622SArd Biesheuvel * and may end up looping here forever.
4152d82e622SArd Biesheuvel */
4162d82e622SArd Biesheuvel if (duplicates &&
4172d82e622SArd Biesheuvel variable_is_present(variable_name, &vendor_guid,
4182d82e622SArd Biesheuvel head)) {
4192d82e622SArd Biesheuvel dup_variable_bug(variable_name, &vendor_guid,
4202d82e622SArd Biesheuvel variable_name_size);
4212d82e622SArd Biesheuvel status = EFI_NOT_FOUND;
4222d82e622SArd Biesheuvel } else {
4232d82e622SArd Biesheuvel err = func(variable_name, vendor_guid,
4242d82e622SArd Biesheuvel variable_name_size, data);
4252d82e622SArd Biesheuvel if (err)
4262d82e622SArd Biesheuvel status = EFI_NOT_FOUND;
4272d82e622SArd Biesheuvel }
4282d82e622SArd Biesheuvel break;
4292d82e622SArd Biesheuvel case EFI_UNSUPPORTED:
4302d82e622SArd Biesheuvel err = -EOPNOTSUPP;
4312d82e622SArd Biesheuvel status = EFI_NOT_FOUND;
4322d82e622SArd Biesheuvel break;
4332d82e622SArd Biesheuvel case EFI_NOT_FOUND:
4342d82e622SArd Biesheuvel break;
435*71da10e6STim Schumacher case EFI_BUFFER_TOO_SMALL:
436*71da10e6STim Schumacher pr_warn("efivars: Variable name size exceeds maximum (%lu > 512)\n",
437*71da10e6STim Schumacher variable_name_size);
438*71da10e6STim Schumacher status = EFI_NOT_FOUND;
439*71da10e6STim Schumacher break;
4402d82e622SArd Biesheuvel default:
441*71da10e6STim Schumacher pr_warn("efivars: get_next_variable: status=%lx\n", status);
4422d82e622SArd Biesheuvel status = EFI_NOT_FOUND;
4432d82e622SArd Biesheuvel break;
4442d82e622SArd Biesheuvel }
4452d82e622SArd Biesheuvel
4462d82e622SArd Biesheuvel } while (status != EFI_NOT_FOUND);
4472d82e622SArd Biesheuvel
4482d82e622SArd Biesheuvel efivar_unlock();
4492d82e622SArd Biesheuvel free:
4502d82e622SArd Biesheuvel kfree(variable_name);
4512d82e622SArd Biesheuvel
4522d82e622SArd Biesheuvel return err;
4532d82e622SArd Biesheuvel }
4542d82e622SArd Biesheuvel
4552d82e622SArd Biesheuvel /**
4562d82e622SArd Biesheuvel * efivar_entry_add - add entry to variable list
4572d82e622SArd Biesheuvel * @entry: entry to add to list
4582d82e622SArd Biesheuvel * @head: list head
4592d82e622SArd Biesheuvel *
4602d82e622SArd Biesheuvel * Returns 0 on success, or a kernel error code on failure.
4612d82e622SArd Biesheuvel */
efivar_entry_add(struct efivar_entry * entry,struct list_head * head)4622d82e622SArd Biesheuvel int efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
4632d82e622SArd Biesheuvel {
4642d82e622SArd Biesheuvel int err;
4652d82e622SArd Biesheuvel
4662d82e622SArd Biesheuvel err = efivar_lock();
4672d82e622SArd Biesheuvel if (err)
4682d82e622SArd Biesheuvel return err;
4692d82e622SArd Biesheuvel list_add(&entry->list, head);
4702d82e622SArd Biesheuvel efivar_unlock();
4712d82e622SArd Biesheuvel
4722d82e622SArd Biesheuvel return 0;
4732d82e622SArd Biesheuvel }
4742d82e622SArd Biesheuvel
4752d82e622SArd Biesheuvel /**
4762d82e622SArd Biesheuvel * __efivar_entry_add - add entry to variable list
4772d82e622SArd Biesheuvel * @entry: entry to add to list
4782d82e622SArd Biesheuvel * @head: list head
4792d82e622SArd Biesheuvel */
__efivar_entry_add(struct efivar_entry * entry,struct list_head * head)4802d82e622SArd Biesheuvel void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
4812d82e622SArd Biesheuvel {
4822d82e622SArd Biesheuvel list_add(&entry->list, head);
4832d82e622SArd Biesheuvel }
4842d82e622SArd Biesheuvel
4852d82e622SArd Biesheuvel /**
4862d82e622SArd Biesheuvel * efivar_entry_remove - remove entry from variable list
4872d82e622SArd Biesheuvel * @entry: entry to remove from list
4882d82e622SArd Biesheuvel *
4892d82e622SArd Biesheuvel * Returns 0 on success, or a kernel error code on failure.
4902d82e622SArd Biesheuvel */
efivar_entry_remove(struct efivar_entry * entry)4912d82e622SArd Biesheuvel void efivar_entry_remove(struct efivar_entry *entry)
4922d82e622SArd Biesheuvel {
4932d82e622SArd Biesheuvel list_del(&entry->list);
4942d82e622SArd Biesheuvel }
4952d82e622SArd Biesheuvel
4962d82e622SArd Biesheuvel /*
4972d82e622SArd Biesheuvel * efivar_entry_list_del_unlock - remove entry from variable list
4982d82e622SArd Biesheuvel * @entry: entry to remove
4992d82e622SArd Biesheuvel *
5002d82e622SArd Biesheuvel * Remove @entry from the variable list and release the list lock.
5012d82e622SArd Biesheuvel *
5022d82e622SArd Biesheuvel * NOTE: slightly weird locking semantics here - we expect to be
5032d82e622SArd Biesheuvel * called with the efivars lock already held, and we release it before
5042d82e622SArd Biesheuvel * returning. This is because this function is usually called after
5052d82e622SArd Biesheuvel * set_variable() while the lock is still held.
5062d82e622SArd Biesheuvel */
efivar_entry_list_del_unlock(struct efivar_entry * entry)5072d82e622SArd Biesheuvel static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
5082d82e622SArd Biesheuvel {
5092d82e622SArd Biesheuvel list_del(&entry->list);
5102d82e622SArd Biesheuvel efivar_unlock();
5112d82e622SArd Biesheuvel }
5122d82e622SArd Biesheuvel
5132d82e622SArd Biesheuvel /**
5142d82e622SArd Biesheuvel * efivar_entry_delete - delete variable and remove entry from list
5152d82e622SArd Biesheuvel * @entry: entry containing variable to delete
5162d82e622SArd Biesheuvel *
5172d82e622SArd Biesheuvel * Delete the variable from the firmware and remove @entry from the
5182d82e622SArd Biesheuvel * variable list. It is the caller's responsibility to free @entry
5192d82e622SArd Biesheuvel * once we return.
5202d82e622SArd Biesheuvel *
5212d82e622SArd Biesheuvel * Returns 0 on success, -EINTR if we can't grab the semaphore,
5222d82e622SArd Biesheuvel * converted EFI status code if set_variable() fails.
5232d82e622SArd Biesheuvel */
efivar_entry_delete(struct efivar_entry * entry)5242d82e622SArd Biesheuvel int efivar_entry_delete(struct efivar_entry *entry)
5252d82e622SArd Biesheuvel {
5262d82e622SArd Biesheuvel efi_status_t status;
5272d82e622SArd Biesheuvel int err;
5282d82e622SArd Biesheuvel
5292d82e622SArd Biesheuvel err = efivar_lock();
5302d82e622SArd Biesheuvel if (err)
5312d82e622SArd Biesheuvel return err;
5322d82e622SArd Biesheuvel
5332d82e622SArd Biesheuvel status = efivar_set_variable_locked(entry->var.VariableName,
5342d82e622SArd Biesheuvel &entry->var.VendorGuid,
5352d82e622SArd Biesheuvel 0, 0, NULL, false);
5362d82e622SArd Biesheuvel if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
5372d82e622SArd Biesheuvel efivar_unlock();
5382d82e622SArd Biesheuvel return efi_status_to_err(status);
5392d82e622SArd Biesheuvel }
5402d82e622SArd Biesheuvel
5412d82e622SArd Biesheuvel efivar_entry_list_del_unlock(entry);
5422d82e622SArd Biesheuvel return 0;
5432d82e622SArd Biesheuvel }
5442d82e622SArd Biesheuvel
5452d82e622SArd Biesheuvel /**
5462d82e622SArd Biesheuvel * efivar_entry_size - obtain the size of a variable
5472d82e622SArd Biesheuvel * @entry: entry for this variable
5482d82e622SArd Biesheuvel * @size: location to store the variable's size
5492d82e622SArd Biesheuvel */
efivar_entry_size(struct efivar_entry * entry,unsigned long * size)5502d82e622SArd Biesheuvel int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
5512d82e622SArd Biesheuvel {
5522d82e622SArd Biesheuvel efi_status_t status;
5532d82e622SArd Biesheuvel int err;
5542d82e622SArd Biesheuvel
5552d82e622SArd Biesheuvel *size = 0;
5562d82e622SArd Biesheuvel
5572d82e622SArd Biesheuvel err = efivar_lock();
5582d82e622SArd Biesheuvel if (err)
5592d82e622SArd Biesheuvel return err;
5602d82e622SArd Biesheuvel
5612d82e622SArd Biesheuvel status = efivar_get_variable(entry->var.VariableName,
5622d82e622SArd Biesheuvel &entry->var.VendorGuid, NULL, size, NULL);
5632d82e622SArd Biesheuvel efivar_unlock();
5642d82e622SArd Biesheuvel
5652d82e622SArd Biesheuvel if (status != EFI_BUFFER_TOO_SMALL)
5662d82e622SArd Biesheuvel return efi_status_to_err(status);
5672d82e622SArd Biesheuvel
5682d82e622SArd Biesheuvel return 0;
5692d82e622SArd Biesheuvel }
5702d82e622SArd Biesheuvel
5712d82e622SArd Biesheuvel /**
5722d82e622SArd Biesheuvel * __efivar_entry_get - call get_variable()
5732d82e622SArd Biesheuvel * @entry: read data for this variable
5742d82e622SArd Biesheuvel * @attributes: variable attributes
5752d82e622SArd Biesheuvel * @size: size of @data buffer
5762d82e622SArd Biesheuvel * @data: buffer to store variable data
5772d82e622SArd Biesheuvel *
5782d82e622SArd Biesheuvel * The caller MUST call efivar_entry_iter_begin() and
5792d82e622SArd Biesheuvel * efivar_entry_iter_end() before and after the invocation of this
5802d82e622SArd Biesheuvel * function, respectively.
5812d82e622SArd Biesheuvel */
__efivar_entry_get(struct efivar_entry * entry,u32 * attributes,unsigned long * size,void * data)5822d82e622SArd Biesheuvel int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
5832d82e622SArd Biesheuvel unsigned long *size, void *data)
5842d82e622SArd Biesheuvel {
5852d82e622SArd Biesheuvel efi_status_t status;
5862d82e622SArd Biesheuvel
5872d82e622SArd Biesheuvel status = efivar_get_variable(entry->var.VariableName,
5882d82e622SArd Biesheuvel &entry->var.VendorGuid,
5892d82e622SArd Biesheuvel attributes, size, data);
5902d82e622SArd Biesheuvel
5912d82e622SArd Biesheuvel return efi_status_to_err(status);
5922d82e622SArd Biesheuvel }
5932d82e622SArd Biesheuvel
5942d82e622SArd Biesheuvel /**
5952d82e622SArd Biesheuvel * efivar_entry_get - call get_variable()
5962d82e622SArd Biesheuvel * @entry: read data for this variable
5972d82e622SArd Biesheuvel * @attributes: variable attributes
5982d82e622SArd Biesheuvel * @size: size of @data buffer
5992d82e622SArd Biesheuvel * @data: buffer to store variable data
6002d82e622SArd Biesheuvel */
efivar_entry_get(struct efivar_entry * entry,u32 * attributes,unsigned long * size,void * data)6012d82e622SArd Biesheuvel int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
6022d82e622SArd Biesheuvel unsigned long *size, void *data)
6032d82e622SArd Biesheuvel {
6042d82e622SArd Biesheuvel int err;
6052d82e622SArd Biesheuvel
6062d82e622SArd Biesheuvel err = efivar_lock();
6072d82e622SArd Biesheuvel if (err)
6082d82e622SArd Biesheuvel return err;
6092d82e622SArd Biesheuvel err = __efivar_entry_get(entry, attributes, size, data);
6102d82e622SArd Biesheuvel efivar_unlock();
6112d82e622SArd Biesheuvel
6122d82e622SArd Biesheuvel return 0;
6132d82e622SArd Biesheuvel }
6142d82e622SArd Biesheuvel
6152d82e622SArd Biesheuvel /**
6162d82e622SArd Biesheuvel * efivar_entry_set_get_size - call set_variable() and get new size (atomic)
6172d82e622SArd Biesheuvel * @entry: entry containing variable to set and get
6182d82e622SArd Biesheuvel * @attributes: attributes of variable to be written
6192d82e622SArd Biesheuvel * @size: size of data buffer
6202d82e622SArd Biesheuvel * @data: buffer containing data to write
6212d82e622SArd Biesheuvel * @set: did the set_variable() call succeed?
6222d82e622SArd Biesheuvel *
6232d82e622SArd Biesheuvel * This is a pretty special (complex) function. See efivarfs_file_write().
6242d82e622SArd Biesheuvel *
6252d82e622SArd Biesheuvel * Atomically call set_variable() for @entry and if the call is
6262d82e622SArd Biesheuvel * successful, return the new size of the variable from get_variable()
6272d82e622SArd Biesheuvel * in @size. The success of set_variable() is indicated by @set.
6282d82e622SArd Biesheuvel *
6292d82e622SArd Biesheuvel * Returns 0 on success, -EINVAL if the variable data is invalid,
6302d82e622SArd Biesheuvel * -ENOSPC if the firmware does not have enough available space, or a
6312d82e622SArd Biesheuvel * converted EFI status code if either of set_variable() or
6322d82e622SArd Biesheuvel * get_variable() fail.
6332d82e622SArd Biesheuvel *
6342d82e622SArd Biesheuvel * If the EFI variable does not exist when calling set_variable()
6352d82e622SArd Biesheuvel * (EFI_NOT_FOUND), @entry is removed from the variable list.
6362d82e622SArd Biesheuvel */
efivar_entry_set_get_size(struct efivar_entry * entry,u32 attributes,unsigned long * size,void * data,bool * set)6372d82e622SArd Biesheuvel int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
6382d82e622SArd Biesheuvel unsigned long *size, void *data, bool *set)
6392d82e622SArd Biesheuvel {
6402d82e622SArd Biesheuvel efi_char16_t *name = entry->var.VariableName;
6412d82e622SArd Biesheuvel efi_guid_t *vendor = &entry->var.VendorGuid;
6422d82e622SArd Biesheuvel efi_status_t status;
6432d82e622SArd Biesheuvel int err;
6442d82e622SArd Biesheuvel
6452d82e622SArd Biesheuvel *set = false;
6462d82e622SArd Biesheuvel
6472d82e622SArd Biesheuvel if (efivar_validate(*vendor, name, data, *size) == false)
6482d82e622SArd Biesheuvel return -EINVAL;
6492d82e622SArd Biesheuvel
6502d82e622SArd Biesheuvel /*
6512d82e622SArd Biesheuvel * The lock here protects the get_variable call, the conditional
6522d82e622SArd Biesheuvel * set_variable call, and removal of the variable from the efivars
6532d82e622SArd Biesheuvel * list (in the case of an authenticated delete).
6542d82e622SArd Biesheuvel */
6552d82e622SArd Biesheuvel err = efivar_lock();
6562d82e622SArd Biesheuvel if (err)
6572d82e622SArd Biesheuvel return err;
6582d82e622SArd Biesheuvel
6592d82e622SArd Biesheuvel status = efivar_set_variable_locked(name, vendor, attributes, *size,
6602d82e622SArd Biesheuvel data, false);
6612d82e622SArd Biesheuvel if (status != EFI_SUCCESS) {
6622d82e622SArd Biesheuvel err = efi_status_to_err(status);
6632d82e622SArd Biesheuvel goto out;
6642d82e622SArd Biesheuvel }
6652d82e622SArd Biesheuvel
6662d82e622SArd Biesheuvel *set = true;
6672d82e622SArd Biesheuvel
6682d82e622SArd Biesheuvel /*
6692d82e622SArd Biesheuvel * Writing to the variable may have caused a change in size (which
6702d82e622SArd Biesheuvel * could either be an append or an overwrite), or the variable to be
6712d82e622SArd Biesheuvel * deleted. Perform a GetVariable() so we can tell what actually
6722d82e622SArd Biesheuvel * happened.
6732d82e622SArd Biesheuvel */
6742d82e622SArd Biesheuvel *size = 0;
6752d82e622SArd Biesheuvel status = efivar_get_variable(entry->var.VariableName,
6762d82e622SArd Biesheuvel &entry->var.VendorGuid,
6772d82e622SArd Biesheuvel NULL, size, NULL);
6782d82e622SArd Biesheuvel
6792d82e622SArd Biesheuvel if (status == EFI_NOT_FOUND)
6802d82e622SArd Biesheuvel efivar_entry_list_del_unlock(entry);
6812d82e622SArd Biesheuvel else
6822d82e622SArd Biesheuvel efivar_unlock();
6832d82e622SArd Biesheuvel
6842d82e622SArd Biesheuvel if (status && status != EFI_BUFFER_TOO_SMALL)
6852d82e622SArd Biesheuvel return efi_status_to_err(status);
6862d82e622SArd Biesheuvel
6872d82e622SArd Biesheuvel return 0;
6882d82e622SArd Biesheuvel
6892d82e622SArd Biesheuvel out:
6902d82e622SArd Biesheuvel efivar_unlock();
6912d82e622SArd Biesheuvel return err;
6922d82e622SArd Biesheuvel
6932d82e622SArd Biesheuvel }
6942d82e622SArd Biesheuvel
6952d82e622SArd Biesheuvel /**
6962d82e622SArd Biesheuvel * efivar_entry_iter - iterate over variable list
6972d82e622SArd Biesheuvel * @func: callback function
6982d82e622SArd Biesheuvel * @head: head of variable list
6992d82e622SArd Biesheuvel * @data: function-specific data to pass to callback
7002d82e622SArd Biesheuvel *
7012d82e622SArd Biesheuvel * Iterate over the list of EFI variables and call @func with every
7022d82e622SArd Biesheuvel * entry on the list. It is safe for @func to remove entries in the
7032d82e622SArd Biesheuvel * list via efivar_entry_delete() while iterating.
7042d82e622SArd Biesheuvel *
7052d82e622SArd Biesheuvel * Some notes for the callback function:
7062d82e622SArd Biesheuvel * - a non-zero return value indicates an error and terminates the loop
7072d82e622SArd Biesheuvel * - @func is called from atomic context
7082d82e622SArd Biesheuvel */
efivar_entry_iter(int (* func)(struct efivar_entry *,void *),struct list_head * head,void * data)7092d82e622SArd Biesheuvel int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
7102d82e622SArd Biesheuvel struct list_head *head, void *data)
7112d82e622SArd Biesheuvel {
7122d82e622SArd Biesheuvel struct efivar_entry *entry, *n;
7132d82e622SArd Biesheuvel int err = 0;
7142d82e622SArd Biesheuvel
7152d82e622SArd Biesheuvel err = efivar_lock();
7162d82e622SArd Biesheuvel if (err)
7172d82e622SArd Biesheuvel return err;
7182d82e622SArd Biesheuvel
7192d82e622SArd Biesheuvel list_for_each_entry_safe(entry, n, head, list) {
7202d82e622SArd Biesheuvel err = func(entry, data);
7212d82e622SArd Biesheuvel if (err)
7222d82e622SArd Biesheuvel break;
7232d82e622SArd Biesheuvel }
7242d82e622SArd Biesheuvel efivar_unlock();
7252d82e622SArd Biesheuvel
7262d82e622SArd Biesheuvel return err;
7272d82e622SArd Biesheuvel }
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