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1219 lines
31 KiB
1219 lines
31 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Originally from efivars.c |
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* |
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* Copyright (C) 2001,2003,2004 Dell <[email protected]> |
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* Copyright (C) 2004 Intel Corporation <[email protected]> |
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*/ |
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|
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#include <linux/capability.h> |
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#include <linux/types.h> |
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#include <linux/errno.h> |
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#include <linux/init.h> |
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#include <linux/mm.h> |
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#include <linux/module.h> |
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#include <linux/string.h> |
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#include <linux/smp.h> |
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#include <linux/efi.h> |
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#include <linux/sysfs.h> |
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#include <linux/device.h> |
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#include <linux/slab.h> |
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#include <linux/ctype.h> |
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#include <linux/ucs2_string.h> |
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|
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/* Private pointer to registered efivars */ |
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static struct efivars *__efivars; |
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|
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/* |
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* efivars_lock protects three things: |
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* 1) efivarfs_list and efivars_sysfs_list |
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* 2) ->ops calls |
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* 3) (un)registration of __efivars |
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*/ |
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static DEFINE_SEMAPHORE(efivars_lock); |
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|
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static bool |
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validate_device_path(efi_char16_t *var_name, int match, u8 *buffer, |
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unsigned long len) |
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{ |
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struct efi_generic_dev_path *node; |
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int offset = 0; |
|
|
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node = (struct efi_generic_dev_path *)buffer; |
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|
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if (len < sizeof(*node)) |
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return false; |
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|
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while (offset <= len - sizeof(*node) && |
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node->length >= sizeof(*node) && |
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node->length <= len - offset) { |
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offset += node->length; |
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|
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if ((node->type == EFI_DEV_END_PATH || |
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node->type == EFI_DEV_END_PATH2) && |
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node->sub_type == EFI_DEV_END_ENTIRE) |
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return true; |
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|
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node = (struct efi_generic_dev_path *)(buffer + offset); |
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} |
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|
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/* |
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* If we're here then either node->length pointed past the end |
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* of the buffer or we reached the end of the buffer without |
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* finding a device path end node. |
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*/ |
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return false; |
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} |
|
|
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static bool |
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validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer, |
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unsigned long len) |
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{ |
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/* An array of 16-bit integers */ |
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if ((len % 2) != 0) |
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return false; |
|
|
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return true; |
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} |
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|
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static bool |
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validate_load_option(efi_char16_t *var_name, int match, u8 *buffer, |
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unsigned long len) |
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{ |
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u16 filepathlength; |
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int i, desclength = 0, namelen; |
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|
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namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN); |
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|
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/* Either "Boot" or "Driver" followed by four digits of hex */ |
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for (i = match; i < match+4; i++) { |
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if (var_name[i] > 127 || |
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hex_to_bin(var_name[i] & 0xff) < 0) |
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return true; |
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} |
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|
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/* Reject it if there's 4 digits of hex and then further content */ |
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if (namelen > match + 4) |
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return false; |
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|
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/* A valid entry must be at least 8 bytes */ |
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if (len < 8) |
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return false; |
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|
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filepathlength = buffer[4] | buffer[5] << 8; |
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|
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/* |
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* There's no stored length for the description, so it has to be |
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* found by hand |
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*/ |
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desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2; |
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|
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/* Each boot entry must have a descriptor */ |
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if (!desclength) |
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return false; |
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|
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/* |
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* If the sum of the length of the description, the claimed filepath |
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* length and the original header are greater than the length of the |
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* variable, it's malformed |
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*/ |
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if ((desclength + filepathlength + 6) > len) |
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return false; |
|
|
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/* |
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* And, finally, check the filepath |
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*/ |
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return validate_device_path(var_name, match, buffer + desclength + 6, |
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filepathlength); |
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} |
|
|
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static bool |
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validate_uint16(efi_char16_t *var_name, int match, u8 *buffer, |
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unsigned long len) |
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{ |
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/* A single 16-bit integer */ |
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if (len != 2) |
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return false; |
|
|
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return true; |
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} |
|
|
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static bool |
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validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer, |
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unsigned long len) |
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{ |
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int i; |
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|
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for (i = 0; i < len; i++) { |
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if (buffer[i] > 127) |
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return false; |
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|
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if (buffer[i] == 0) |
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return true; |
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} |
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|
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return false; |
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} |
|
|
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struct variable_validate { |
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efi_guid_t vendor; |
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char *name; |
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bool (*validate)(efi_char16_t *var_name, int match, u8 *data, |
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unsigned long len); |
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}; |
|
|
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/* |
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* This is the list of variables we need to validate, as well as the |
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* whitelist for what we think is safe not to default to immutable. |
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* |
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* If it has a validate() method that's not NULL, it'll go into the |
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* validation routine. If not, it is assumed valid, but still used for |
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* whitelisting. |
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* |
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* Note that it's sorted by {vendor,name}, but globbed names must come after |
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* any other name with the same prefix. |
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*/ |
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static const struct variable_validate variable_validate[] = { |
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{ EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string }, |
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{ EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 }, |
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{ LINUX_EFI_CRASH_GUID, "*", NULL }, |
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{ NULL_GUID, "", NULL }, |
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}; |
|
|
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/* |
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* Check if @var_name matches the pattern given in @match_name. |
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* |
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* @var_name: an array of @len non-NUL characters. |
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* @match_name: a NUL-terminated pattern string, optionally ending in "*". A |
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* final "*" character matches any trailing characters @var_name, |
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* including the case when there are none left in @var_name. |
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* @match: on output, the number of non-wildcard characters in @match_name |
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* that @var_name matches, regardless of the return value. |
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* @return: whether @var_name fully matches @match_name. |
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*/ |
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static bool |
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variable_matches(const char *var_name, size_t len, const char *match_name, |
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int *match) |
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{ |
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for (*match = 0; ; (*match)++) { |
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char c = match_name[*match]; |
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|
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switch (c) { |
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case '*': |
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/* Wildcard in @match_name means we've matched. */ |
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return true; |
|
|
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case '\0': |
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/* @match_name has ended. Has @var_name too? */ |
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return (*match == len); |
|
|
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default: |
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/* |
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* We've reached a non-wildcard char in @match_name. |
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* Continue only if there's an identical character in |
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* @var_name. |
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*/ |
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if (*match < len && c == var_name[*match]) |
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continue; |
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return false; |
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} |
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} |
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} |
|
|
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bool |
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efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data, |
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unsigned long data_size) |
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{ |
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int i; |
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unsigned long utf8_size; |
|
u8 *utf8_name; |
|
|
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utf8_size = ucs2_utf8size(var_name); |
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utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL); |
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if (!utf8_name) |
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return false; |
|
|
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ucs2_as_utf8(utf8_name, var_name, utf8_size); |
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utf8_name[utf8_size] = '\0'; |
|
|
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for (i = 0; variable_validate[i].name[0] != '\0'; i++) { |
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const char *name = variable_validate[i].name; |
|
int match = 0; |
|
|
|
if (efi_guidcmp(vendor, variable_validate[i].vendor)) |
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continue; |
|
|
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if (variable_matches(utf8_name, utf8_size+1, name, &match)) { |
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if (variable_validate[i].validate == NULL) |
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break; |
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kfree(utf8_name); |
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return variable_validate[i].validate(var_name, match, |
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data, data_size); |
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} |
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} |
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kfree(utf8_name); |
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return true; |
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} |
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EXPORT_SYMBOL_GPL(efivar_validate); |
|
|
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bool |
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efivar_variable_is_removable(efi_guid_t vendor, const char *var_name, |
|
size_t len) |
|
{ |
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int i; |
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bool found = false; |
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int match = 0; |
|
|
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/* |
|
* Check if our variable is in the validated variables list |
|
*/ |
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for (i = 0; variable_validate[i].name[0] != '\0'; i++) { |
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if (efi_guidcmp(variable_validate[i].vendor, vendor)) |
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continue; |
|
|
|
if (variable_matches(var_name, len, |
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variable_validate[i].name, &match)) { |
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found = true; |
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break; |
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} |
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} |
|
|
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/* |
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* If it's in our list, it is removable. |
|
*/ |
|
return found; |
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} |
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EXPORT_SYMBOL_GPL(efivar_variable_is_removable); |
|
|
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static efi_status_t |
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check_var_size(u32 attributes, unsigned long size) |
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{ |
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const struct efivar_operations *fops; |
|
|
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if (!__efivars) |
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return EFI_UNSUPPORTED; |
|
|
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fops = __efivars->ops; |
|
|
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if (!fops->query_variable_store) |
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return EFI_UNSUPPORTED; |
|
|
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return fops->query_variable_store(attributes, size, false); |
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} |
|
|
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static efi_status_t |
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check_var_size_nonblocking(u32 attributes, unsigned long size) |
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{ |
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const struct efivar_operations *fops; |
|
|
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if (!__efivars) |
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return EFI_UNSUPPORTED; |
|
|
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fops = __efivars->ops; |
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|
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if (!fops->query_variable_store) |
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return EFI_UNSUPPORTED; |
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|
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return fops->query_variable_store(attributes, size, true); |
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} |
|
|
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static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor, |
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struct list_head *head) |
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{ |
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struct efivar_entry *entry, *n; |
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unsigned long strsize1, strsize2; |
|
bool found = false; |
|
|
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strsize1 = ucs2_strsize(variable_name, 1024); |
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list_for_each_entry_safe(entry, n, head, list) { |
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strsize2 = ucs2_strsize(entry->var.VariableName, 1024); |
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if (strsize1 == strsize2 && |
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!memcmp(variable_name, &(entry->var.VariableName), |
|
strsize2) && |
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!efi_guidcmp(entry->var.VendorGuid, |
|
*vendor)) { |
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found = true; |
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break; |
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} |
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} |
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return found; |
|
} |
|
|
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/* |
|
* Returns the size of variable_name, in bytes, including the |
|
* terminating NULL character, or variable_name_size if no NULL |
|
* character is found among the first variable_name_size bytes. |
|
*/ |
|
static unsigned long var_name_strnsize(efi_char16_t *variable_name, |
|
unsigned long variable_name_size) |
|
{ |
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unsigned long len; |
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efi_char16_t c; |
|
|
|
/* |
|
* The variable name is, by definition, a NULL-terminated |
|
* string, so make absolutely sure that variable_name_size is |
|
* the value we expect it to be. If not, return the real size. |
|
*/ |
|
for (len = 2; len <= variable_name_size; len += sizeof(c)) { |
|
c = variable_name[(len / sizeof(c)) - 1]; |
|
if (!c) |
|
break; |
|
} |
|
|
|
return min(len, variable_name_size); |
|
} |
|
|
|
/* |
|
* Print a warning when duplicate EFI variables are encountered and |
|
* disable the sysfs workqueue since the firmware is buggy. |
|
*/ |
|
static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid, |
|
unsigned long len16) |
|
{ |
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size_t i, len8 = len16 / sizeof(efi_char16_t); |
|
char *str8; |
|
|
|
str8 = kzalloc(len8, GFP_KERNEL); |
|
if (!str8) |
|
return; |
|
|
|
for (i = 0; i < len8; i++) |
|
str8[i] = str16[i]; |
|
|
|
printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", |
|
str8, vendor_guid); |
|
kfree(str8); |
|
} |
|
|
|
/** |
|
* efivar_init - build the initial list of EFI variables |
|
* @func: callback function to invoke for every variable |
|
* @data: function-specific data to pass to @func |
|
* @duplicates: error if we encounter duplicates on @head? |
|
* @head: initialised head of variable list |
|
* |
|
* Get every EFI variable from the firmware and invoke @func. @func |
|
* should call efivar_entry_add() to build the list of variables. |
|
* |
|
* Returns 0 on success, or a kernel error code on failure. |
|
*/ |
|
int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), |
|
void *data, bool duplicates, struct list_head *head) |
|
{ |
|
const struct efivar_operations *ops; |
|
unsigned long variable_name_size = 1024; |
|
efi_char16_t *variable_name; |
|
efi_status_t status; |
|
efi_guid_t vendor_guid; |
|
int err = 0; |
|
|
|
if (!__efivars) |
|
return -EFAULT; |
|
|
|
ops = __efivars->ops; |
|
|
|
variable_name = kzalloc(variable_name_size, GFP_KERNEL); |
|
if (!variable_name) { |
|
printk(KERN_ERR "efivars: Memory allocation failed.\n"); |
|
return -ENOMEM; |
|
} |
|
|
|
if (down_interruptible(&efivars_lock)) { |
|
err = -EINTR; |
|
goto free; |
|
} |
|
|
|
/* |
|
* Per EFI spec, the maximum storage allocated for both |
|
* the variable name and variable data is 1024 bytes. |
|
*/ |
|
|
|
do { |
|
variable_name_size = 1024; |
|
|
|
status = ops->get_next_variable(&variable_name_size, |
|
variable_name, |
|
&vendor_guid); |
|
switch (status) { |
|
case EFI_SUCCESS: |
|
if (duplicates) |
|
up(&efivars_lock); |
|
|
|
variable_name_size = var_name_strnsize(variable_name, |
|
variable_name_size); |
|
|
|
/* |
|
* Some firmware implementations return the |
|
* same variable name on multiple calls to |
|
* get_next_variable(). Terminate the loop |
|
* immediately as there is no guarantee that |
|
* we'll ever see a different variable name, |
|
* and may end up looping here forever. |
|
*/ |
|
if (duplicates && |
|
variable_is_present(variable_name, &vendor_guid, |
|
head)) { |
|
dup_variable_bug(variable_name, &vendor_guid, |
|
variable_name_size); |
|
status = EFI_NOT_FOUND; |
|
} else { |
|
err = func(variable_name, vendor_guid, |
|
variable_name_size, data); |
|
if (err) |
|
status = EFI_NOT_FOUND; |
|
} |
|
|
|
if (duplicates) { |
|
if (down_interruptible(&efivars_lock)) { |
|
err = -EINTR; |
|
goto free; |
|
} |
|
} |
|
|
|
break; |
|
case EFI_UNSUPPORTED: |
|
err = -EOPNOTSUPP; |
|
status = EFI_NOT_FOUND; |
|
break; |
|
case EFI_NOT_FOUND: |
|
break; |
|
default: |
|
printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n", |
|
status); |
|
status = EFI_NOT_FOUND; |
|
break; |
|
} |
|
|
|
} while (status != EFI_NOT_FOUND); |
|
|
|
up(&efivars_lock); |
|
free: |
|
kfree(variable_name); |
|
|
|
return err; |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_init); |
|
|
|
/** |
|
* efivar_entry_add - add entry to variable list |
|
* @entry: entry to add to list |
|
* @head: list head |
|
* |
|
* Returns 0 on success, or a kernel error code on failure. |
|
*/ |
|
int efivar_entry_add(struct efivar_entry *entry, struct list_head *head) |
|
{ |
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
list_add(&entry->list, head); |
|
up(&efivars_lock); |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_add); |
|
|
|
/** |
|
* efivar_entry_remove - remove entry from variable list |
|
* @entry: entry to remove from list |
|
* |
|
* Returns 0 on success, or a kernel error code on failure. |
|
*/ |
|
int efivar_entry_remove(struct efivar_entry *entry) |
|
{ |
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
list_del(&entry->list); |
|
up(&efivars_lock); |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_remove); |
|
|
|
/* |
|
* efivar_entry_list_del_unlock - remove entry from variable list |
|
* @entry: entry to remove |
|
* |
|
* Remove @entry from the variable list and release the list lock. |
|
* |
|
* NOTE: slightly weird locking semantics here - we expect to be |
|
* called with the efivars lock already held, and we release it before |
|
* returning. This is because this function is usually called after |
|
* set_variable() while the lock is still held. |
|
*/ |
|
static void efivar_entry_list_del_unlock(struct efivar_entry *entry) |
|
{ |
|
list_del(&entry->list); |
|
up(&efivars_lock); |
|
} |
|
|
|
/** |
|
* __efivar_entry_delete - delete an EFI variable |
|
* @entry: entry containing EFI variable to delete |
|
* |
|
* Delete the variable from the firmware but leave @entry on the |
|
* variable list. |
|
* |
|
* This function differs from efivar_entry_delete() because it does |
|
* not remove @entry from the variable list. Also, it is safe to be |
|
* called from within a efivar_entry_iter_begin() and |
|
* efivar_entry_iter_end() region, unlike efivar_entry_delete(). |
|
* |
|
* Returns 0 on success, or a converted EFI status code if |
|
* set_variable() fails. |
|
*/ |
|
int __efivar_entry_delete(struct efivar_entry *entry) |
|
{ |
|
efi_status_t status; |
|
|
|
if (!__efivars) |
|
return -EINVAL; |
|
|
|
status = __efivars->ops->set_variable(entry->var.VariableName, |
|
&entry->var.VendorGuid, |
|
0, 0, NULL); |
|
|
|
return efi_status_to_err(status); |
|
} |
|
EXPORT_SYMBOL_GPL(__efivar_entry_delete); |
|
|
|
/** |
|
* efivar_entry_delete - delete variable and remove entry from list |
|
* @entry: entry containing variable to delete |
|
* |
|
* Delete the variable from the firmware and remove @entry from the |
|
* variable list. It is the caller's responsibility to free @entry |
|
* once we return. |
|
* |
|
* Returns 0 on success, -EINTR if we can't grab the semaphore, |
|
* converted EFI status code if set_variable() fails. |
|
*/ |
|
int efivar_entry_delete(struct efivar_entry *entry) |
|
{ |
|
const struct efivar_operations *ops; |
|
efi_status_t status; |
|
|
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
|
|
if (!__efivars) { |
|
up(&efivars_lock); |
|
return -EINVAL; |
|
} |
|
ops = __efivars->ops; |
|
status = ops->set_variable(entry->var.VariableName, |
|
&entry->var.VendorGuid, |
|
0, 0, NULL); |
|
if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) { |
|
up(&efivars_lock); |
|
return efi_status_to_err(status); |
|
} |
|
|
|
efivar_entry_list_del_unlock(entry); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_delete); |
|
|
|
/** |
|
* efivar_entry_set - call set_variable() |
|
* @entry: entry containing the EFI variable to write |
|
* @attributes: variable attributes |
|
* @size: size of @data buffer |
|
* @data: buffer containing variable data |
|
* @head: head of variable list |
|
* |
|
* Calls set_variable() for an EFI variable. If creating a new EFI |
|
* variable, this function is usually followed by efivar_entry_add(). |
|
* |
|
* Before writing the variable, the remaining EFI variable storage |
|
* space is checked to ensure there is enough room available. |
|
* |
|
* If @head is not NULL a lookup is performed to determine whether |
|
* the entry is already on the list. |
|
* |
|
* Returns 0 on success, -EINTR if we can't grab the semaphore, |
|
* -EEXIST if a lookup is performed and the entry already exists on |
|
* the list, or a converted EFI status code if set_variable() fails. |
|
*/ |
|
int efivar_entry_set(struct efivar_entry *entry, u32 attributes, |
|
unsigned long size, void *data, struct list_head *head) |
|
{ |
|
const struct efivar_operations *ops; |
|
efi_status_t status; |
|
efi_char16_t *name = entry->var.VariableName; |
|
efi_guid_t vendor = entry->var.VendorGuid; |
|
|
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
|
|
if (!__efivars) { |
|
up(&efivars_lock); |
|
return -EINVAL; |
|
} |
|
ops = __efivars->ops; |
|
if (head && efivar_entry_find(name, vendor, head, false)) { |
|
up(&efivars_lock); |
|
return -EEXIST; |
|
} |
|
|
|
status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
|
if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED) |
|
status = ops->set_variable(name, &vendor, |
|
attributes, size, data); |
|
|
|
up(&efivars_lock); |
|
|
|
return efi_status_to_err(status); |
|
|
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_set); |
|
|
|
/* |
|
* efivar_entry_set_nonblocking - call set_variable_nonblocking() |
|
* |
|
* This function is guaranteed to not block and is suitable for calling |
|
* from crash/panic handlers. |
|
* |
|
* Crucially, this function will not block if it cannot acquire |
|
* efivars_lock. Instead, it returns -EBUSY. |
|
*/ |
|
static int |
|
efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor, |
|
u32 attributes, unsigned long size, void *data) |
|
{ |
|
const struct efivar_operations *ops; |
|
efi_status_t status; |
|
|
|
if (down_trylock(&efivars_lock)) |
|
return -EBUSY; |
|
|
|
if (!__efivars) { |
|
up(&efivars_lock); |
|
return -EINVAL; |
|
} |
|
|
|
status = check_var_size_nonblocking(attributes, |
|
size + ucs2_strsize(name, 1024)); |
|
if (status != EFI_SUCCESS) { |
|
up(&efivars_lock); |
|
return -ENOSPC; |
|
} |
|
|
|
ops = __efivars->ops; |
|
status = ops->set_variable_nonblocking(name, &vendor, attributes, |
|
size, data); |
|
|
|
up(&efivars_lock); |
|
return efi_status_to_err(status); |
|
} |
|
|
|
/** |
|
* efivar_entry_set_safe - call set_variable() if enough space in firmware |
|
* @name: buffer containing the variable name |
|
* @vendor: variable vendor guid |
|
* @attributes: variable attributes |
|
* @block: can we block in this context? |
|
* @size: size of @data buffer |
|
* @data: buffer containing variable data |
|
* |
|
* Ensures there is enough free storage in the firmware for this variable, and |
|
* if so, calls set_variable(). If creating a new EFI variable, this function |
|
* is usually followed by efivar_entry_add(). |
|
* |
|
* Returns 0 on success, -ENOSPC if the firmware does not have enough |
|
* space for set_variable() to succeed, or a converted EFI status code |
|
* if set_variable() fails. |
|
*/ |
|
int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes, |
|
bool block, unsigned long size, void *data) |
|
{ |
|
const struct efivar_operations *ops; |
|
efi_status_t status; |
|
|
|
if (!__efivars) |
|
return -EINVAL; |
|
|
|
ops = __efivars->ops; |
|
if (!ops->query_variable_store) |
|
return -ENOSYS; |
|
|
|
/* |
|
* If the EFI variable backend provides a non-blocking |
|
* ->set_variable() operation and we're in a context where we |
|
* cannot block, then we need to use it to avoid live-locks, |
|
* since the implication is that the regular ->set_variable() |
|
* will block. |
|
* |
|
* If no ->set_variable_nonblocking() is provided then |
|
* ->set_variable() is assumed to be non-blocking. |
|
*/ |
|
if (!block && ops->set_variable_nonblocking) |
|
return efivar_entry_set_nonblocking(name, vendor, attributes, |
|
size, data); |
|
|
|
if (!block) { |
|
if (down_trylock(&efivars_lock)) |
|
return -EBUSY; |
|
} else { |
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
} |
|
|
|
status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
|
if (status != EFI_SUCCESS) { |
|
up(&efivars_lock); |
|
return -ENOSPC; |
|
} |
|
|
|
status = ops->set_variable(name, &vendor, attributes, size, data); |
|
|
|
up(&efivars_lock); |
|
|
|
return efi_status_to_err(status); |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_set_safe); |
|
|
|
/** |
|
* efivar_entry_find - search for an entry |
|
* @name: the EFI variable name |
|
* @guid: the EFI variable vendor's guid |
|
* @head: head of the variable list |
|
* @remove: should we remove the entry from the list? |
|
* |
|
* Search for an entry on the variable list that has the EFI variable |
|
* name @name and vendor guid @guid. If an entry is found on the list |
|
* and @remove is true, the entry is removed from the list. |
|
* |
|
* The caller MUST call efivar_entry_iter_begin() and |
|
* efivar_entry_iter_end() before and after the invocation of this |
|
* function, respectively. |
|
* |
|
* Returns the entry if found on the list, %NULL otherwise. |
|
*/ |
|
struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid, |
|
struct list_head *head, bool remove) |
|
{ |
|
struct efivar_entry *entry, *n; |
|
int strsize1, strsize2; |
|
bool found = false; |
|
|
|
list_for_each_entry_safe(entry, n, head, list) { |
|
strsize1 = ucs2_strsize(name, 1024); |
|
strsize2 = ucs2_strsize(entry->var.VariableName, 1024); |
|
if (strsize1 == strsize2 && |
|
!memcmp(name, &(entry->var.VariableName), strsize1) && |
|
!efi_guidcmp(guid, entry->var.VendorGuid)) { |
|
found = true; |
|
break; |
|
} |
|
} |
|
|
|
if (!found) |
|
return NULL; |
|
|
|
if (remove) { |
|
if (entry->scanning) { |
|
/* |
|
* The entry will be deleted |
|
* after scanning is completed. |
|
*/ |
|
entry->deleting = true; |
|
} else |
|
list_del(&entry->list); |
|
} |
|
|
|
return entry; |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_find); |
|
|
|
/** |
|
* efivar_entry_size - obtain the size of a variable |
|
* @entry: entry for this variable |
|
* @size: location to store the variable's size |
|
*/ |
|
int efivar_entry_size(struct efivar_entry *entry, unsigned long *size) |
|
{ |
|
const struct efivar_operations *ops; |
|
efi_status_t status; |
|
|
|
*size = 0; |
|
|
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
if (!__efivars) { |
|
up(&efivars_lock); |
|
return -EINVAL; |
|
} |
|
ops = __efivars->ops; |
|
status = ops->get_variable(entry->var.VariableName, |
|
&entry->var.VendorGuid, NULL, size, NULL); |
|
up(&efivars_lock); |
|
|
|
if (status != EFI_BUFFER_TOO_SMALL) |
|
return efi_status_to_err(status); |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_size); |
|
|
|
/** |
|
* __efivar_entry_get - call get_variable() |
|
* @entry: read data for this variable |
|
* @attributes: variable attributes |
|
* @size: size of @data buffer |
|
* @data: buffer to store variable data |
|
* |
|
* The caller MUST call efivar_entry_iter_begin() and |
|
* efivar_entry_iter_end() before and after the invocation of this |
|
* function, respectively. |
|
*/ |
|
int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
|
unsigned long *size, void *data) |
|
{ |
|
efi_status_t status; |
|
|
|
if (!__efivars) |
|
return -EINVAL; |
|
|
|
status = __efivars->ops->get_variable(entry->var.VariableName, |
|
&entry->var.VendorGuid, |
|
attributes, size, data); |
|
|
|
return efi_status_to_err(status); |
|
} |
|
EXPORT_SYMBOL_GPL(__efivar_entry_get); |
|
|
|
/** |
|
* efivar_entry_get - call get_variable() |
|
* @entry: read data for this variable |
|
* @attributes: variable attributes |
|
* @size: size of @data buffer |
|
* @data: buffer to store variable data |
|
*/ |
|
int efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
|
unsigned long *size, void *data) |
|
{ |
|
efi_status_t status; |
|
|
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
|
|
if (!__efivars) { |
|
up(&efivars_lock); |
|
return -EINVAL; |
|
} |
|
|
|
status = __efivars->ops->get_variable(entry->var.VariableName, |
|
&entry->var.VendorGuid, |
|
attributes, size, data); |
|
up(&efivars_lock); |
|
|
|
return efi_status_to_err(status); |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_get); |
|
|
|
/** |
|
* efivar_entry_set_get_size - call set_variable() and get new size (atomic) |
|
* @entry: entry containing variable to set and get |
|
* @attributes: attributes of variable to be written |
|
* @size: size of data buffer |
|
* @data: buffer containing data to write |
|
* @set: did the set_variable() call succeed? |
|
* |
|
* This is a pretty special (complex) function. See efivarfs_file_write(). |
|
* |
|
* Atomically call set_variable() for @entry and if the call is |
|
* successful, return the new size of the variable from get_variable() |
|
* in @size. The success of set_variable() is indicated by @set. |
|
* |
|
* Returns 0 on success, -EINVAL if the variable data is invalid, |
|
* -ENOSPC if the firmware does not have enough available space, or a |
|
* converted EFI status code if either of set_variable() or |
|
* get_variable() fail. |
|
* |
|
* If the EFI variable does not exist when calling set_variable() |
|
* (EFI_NOT_FOUND), @entry is removed from the variable list. |
|
*/ |
|
int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes, |
|
unsigned long *size, void *data, bool *set) |
|
{ |
|
const struct efivar_operations *ops; |
|
efi_char16_t *name = entry->var.VariableName; |
|
efi_guid_t *vendor = &entry->var.VendorGuid; |
|
efi_status_t status; |
|
int err; |
|
|
|
*set = false; |
|
|
|
if (efivar_validate(*vendor, name, data, *size) == false) |
|
return -EINVAL; |
|
|
|
/* |
|
* The lock here protects the get_variable call, the conditional |
|
* set_variable call, and removal of the variable from the efivars |
|
* list (in the case of an authenticated delete). |
|
*/ |
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
|
|
if (!__efivars) { |
|
err = -EINVAL; |
|
goto out; |
|
} |
|
|
|
/* |
|
* Ensure that the available space hasn't shrunk below the safe level |
|
*/ |
|
status = check_var_size(attributes, *size + ucs2_strsize(name, 1024)); |
|
if (status != EFI_SUCCESS) { |
|
if (status != EFI_UNSUPPORTED) { |
|
err = efi_status_to_err(status); |
|
goto out; |
|
} |
|
|
|
if (*size > 65536) { |
|
err = -ENOSPC; |
|
goto out; |
|
} |
|
} |
|
|
|
ops = __efivars->ops; |
|
|
|
status = ops->set_variable(name, vendor, attributes, *size, data); |
|
if (status != EFI_SUCCESS) { |
|
err = efi_status_to_err(status); |
|
goto out; |
|
} |
|
|
|
*set = true; |
|
|
|
/* |
|
* Writing to the variable may have caused a change in size (which |
|
* could either be an append or an overwrite), or the variable to be |
|
* deleted. Perform a GetVariable() so we can tell what actually |
|
* happened. |
|
*/ |
|
*size = 0; |
|
status = ops->get_variable(entry->var.VariableName, |
|
&entry->var.VendorGuid, |
|
NULL, size, NULL); |
|
|
|
if (status == EFI_NOT_FOUND) |
|
efivar_entry_list_del_unlock(entry); |
|
else |
|
up(&efivars_lock); |
|
|
|
if (status && status != EFI_BUFFER_TOO_SMALL) |
|
return efi_status_to_err(status); |
|
|
|
return 0; |
|
|
|
out: |
|
up(&efivars_lock); |
|
return err; |
|
|
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_set_get_size); |
|
|
|
/** |
|
* efivar_entry_iter_begin - begin iterating the variable list |
|
* |
|
* Lock the variable list to prevent entry insertion and removal until |
|
* efivar_entry_iter_end() is called. This function is usually used in |
|
* conjunction with __efivar_entry_iter() or efivar_entry_iter(). |
|
*/ |
|
int efivar_entry_iter_begin(void) |
|
{ |
|
return down_interruptible(&efivars_lock); |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_iter_begin); |
|
|
|
/** |
|
* efivar_entry_iter_end - finish iterating the variable list |
|
* |
|
* Unlock the variable list and allow modifications to the list again. |
|
*/ |
|
void efivar_entry_iter_end(void) |
|
{ |
|
up(&efivars_lock); |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_iter_end); |
|
|
|
/** |
|
* __efivar_entry_iter - iterate over variable list |
|
* @func: callback function |
|
* @head: head of the variable list |
|
* @data: function-specific data to pass to callback |
|
* @prev: entry to begin iterating from |
|
* |
|
* Iterate over the list of EFI variables and call @func with every |
|
* entry on the list. It is safe for @func to remove entries in the |
|
* list via efivar_entry_delete(). |
|
* |
|
* You MUST call efivar_entry_iter_begin() before this function, and |
|
* efivar_entry_iter_end() afterwards. |
|
* |
|
* It is possible to begin iteration from an arbitrary entry within |
|
* the list by passing @prev. @prev is updated on return to point to |
|
* the last entry passed to @func. To begin iterating from the |
|
* beginning of the list @prev must be %NULL. |
|
* |
|
* The restrictions for @func are the same as documented for |
|
* efivar_entry_iter(). |
|
*/ |
|
int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *), |
|
struct list_head *head, void *data, |
|
struct efivar_entry **prev) |
|
{ |
|
struct efivar_entry *entry, *n; |
|
int err = 0; |
|
|
|
if (!prev || !*prev) { |
|
list_for_each_entry_safe(entry, n, head, list) { |
|
err = func(entry, data); |
|
if (err) |
|
break; |
|
} |
|
|
|
if (prev) |
|
*prev = entry; |
|
|
|
return err; |
|
} |
|
|
|
|
|
list_for_each_entry_safe_continue((*prev), n, head, list) { |
|
err = func(*prev, data); |
|
if (err) |
|
break; |
|
} |
|
|
|
return err; |
|
} |
|
EXPORT_SYMBOL_GPL(__efivar_entry_iter); |
|
|
|
/** |
|
* efivar_entry_iter - iterate over variable list |
|
* @func: callback function |
|
* @head: head of variable list |
|
* @data: function-specific data to pass to callback |
|
* |
|
* Iterate over the list of EFI variables and call @func with every |
|
* entry on the list. It is safe for @func to remove entries in the |
|
* list via efivar_entry_delete() while iterating. |
|
* |
|
* Some notes for the callback function: |
|
* - a non-zero return value indicates an error and terminates the loop |
|
* - @func is called from atomic context |
|
*/ |
|
int efivar_entry_iter(int (*func)(struct efivar_entry *, void *), |
|
struct list_head *head, void *data) |
|
{ |
|
int err = 0; |
|
|
|
err = efivar_entry_iter_begin(); |
|
if (err) |
|
return err; |
|
err = __efivar_entry_iter(func, head, data, NULL); |
|
efivar_entry_iter_end(); |
|
|
|
return err; |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_entry_iter); |
|
|
|
/** |
|
* efivars_kobject - get the kobject for the registered efivars |
|
* |
|
* If efivars_register() has not been called we return NULL, |
|
* otherwise return the kobject used at registration time. |
|
*/ |
|
struct kobject *efivars_kobject(void) |
|
{ |
|
if (!__efivars) |
|
return NULL; |
|
|
|
return __efivars->kobject; |
|
} |
|
EXPORT_SYMBOL_GPL(efivars_kobject); |
|
|
|
/** |
|
* efivars_register - register an efivars |
|
* @efivars: efivars to register |
|
* @ops: efivars operations |
|
* @kobject: @efivars-specific kobject |
|
* |
|
* Only a single efivars can be registered at any time. |
|
*/ |
|
int efivars_register(struct efivars *efivars, |
|
const struct efivar_operations *ops, |
|
struct kobject *kobject) |
|
{ |
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
|
|
efivars->ops = ops; |
|
efivars->kobject = kobject; |
|
|
|
__efivars = efivars; |
|
|
|
pr_info("Registered efivars operations\n"); |
|
|
|
up(&efivars_lock); |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(efivars_register); |
|
|
|
/** |
|
* efivars_unregister - unregister an efivars |
|
* @efivars: efivars to unregister |
|
* |
|
* The caller must have already removed every entry from the list, |
|
* failure to do so is an error. |
|
*/ |
|
int efivars_unregister(struct efivars *efivars) |
|
{ |
|
int rv; |
|
|
|
if (down_interruptible(&efivars_lock)) |
|
return -EINTR; |
|
|
|
if (!__efivars) { |
|
printk(KERN_ERR "efivars not registered\n"); |
|
rv = -EINVAL; |
|
goto out; |
|
} |
|
|
|
if (__efivars != efivars) { |
|
rv = -EINVAL; |
|
goto out; |
|
} |
|
|
|
pr_info("Unregistered efivars operations\n"); |
|
__efivars = NULL; |
|
|
|
rv = 0; |
|
out: |
|
up(&efivars_lock); |
|
return rv; |
|
} |
|
EXPORT_SYMBOL_GPL(efivars_unregister); |
|
|
|
int efivar_supports_writes(void) |
|
{ |
|
return __efivars && __efivars->ops->set_variable; |
|
} |
|
EXPORT_SYMBOL_GPL(efivar_supports_writes);
|
|
|