lib/efi_loader/efi_variable.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * UEFI runtime variable services
  *
  * Copyright (c) 2017 Rob Clark
  */

 #define LOG_CATEGORY LOGC_EFI

 #include <common.h>
 #include <efi_loader.h>
 #include <efi_variable.h>
 #include <env.h>
 #include <env_internal.h>
 #include <hexdump.h>
 #include <log.h>
 #include <malloc.h>
 #include <rtc.h>
 #include <search.h>
 #include <uuid.h>
 #include <crypto/pkcs7_parser.h>
 #include <linux/compat.h>
 #include <u-boot/crc.h>
 #include <asm/sections.h>

 #ifdef CONFIG_EFI_SECURE_BOOT
 static u8 pkcs7_hdr[] = {
 	/* SEQUENCE */
 	0x30, 0x82, 0x05, 0xc7,
 	/* OID: pkcs7-signedData */
 	0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x02,
 	/* Context Structured? */
 	0xa0, 0x82, 0x05, 0xb8,
 };

 /**
  * efi_variable_parse_signature - parse a signature in variable
  * @buf:	Pointer to variable's value
  * @buflen:	Length of @buf
  *
  * Parse a signature embedded in variable's value and instantiate
  * a pkcs7_message structure. Since pkcs7_parse_message() accepts only
  * pkcs7's signedData, some header needed be prepended for correctly
  * parsing authentication data, particularly for variable's.
  *
  * Return:	Pointer to pkcs7_message structure on success, NULL on error
  */
 static struct pkcs7_message *efi_variable_parse_signature(const void *buf,
 							  size_t buflen)
 {
 	u8 *ebuf;
 	size_t ebuflen, len;
 	struct pkcs7_message *msg;

 	/*
 	 * This is the best assumption to check if the binary is
 	 * already in a form of pkcs7's signedData.
 	 */
 	if (buflen > sizeof(pkcs7_hdr) &&
 	    !memcmp(&((u8 *)buf)[4], &pkcs7_hdr[4], 11)) {
 		msg = pkcs7_parse_message(buf, buflen);
 		goto out;
 	}

 	/*
 	 * Otherwise, we should add a dummy prefix sequence for pkcs7
 	 * message parser to be able to process.
 	 * NOTE: EDK2 also uses similar hack in WrapPkcs7Data()
 	 * in CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7VerifyCommon.c
 	 * TODO:
 	 * The header should be composed in a more refined manner.
 	 */
 	EFI_PRINT("Makeshift prefix added to authentication data\n");
 	ebuflen = sizeof(pkcs7_hdr) + buflen;
 	if (ebuflen <= 0x7f) {
 		EFI_PRINT("Data is too short\n");
 		return NULL;
 	}

 	ebuf = malloc(ebuflen);
 	if (!ebuf) {
 		EFI_PRINT("Out of memory\n");
 		return NULL;
 	}

 	memcpy(ebuf, pkcs7_hdr, sizeof(pkcs7_hdr));
 	memcpy(ebuf + sizeof(pkcs7_hdr), buf, buflen);
 	len = ebuflen - 4;
 	ebuf[2] = (len >> 8) & 0xff;
 	ebuf[3] = len & 0xff;
 	len = ebuflen - 0x13;
 	ebuf[0x11] = (len >> 8) & 0xff;
 	ebuf[0x12] = len & 0xff;

 	msg = pkcs7_parse_message(ebuf, ebuflen);

 	free(ebuf);

 out:
 	if (IS_ERR(msg))
 		return NULL;

 	return msg;
 }

 /**
  * efi_variable_authenticate - authenticate a variable
  * @variable:	Variable name in u16
  * @vendor:	Guid of variable
  * @data_size:	Size of @data
  * @data:	Pointer to variable's value
  * @given_attr:	Attributes to be given at SetVariable()
  * @env_attr:	Attributes that an existing variable holds
  * @time:	signed time that an existing variable holds
  *
  * Called by efi_set_variable() to verify that the input is correct.
  * Will replace the given data pointer with another that points to
  * the actual data to store in the internal memory.
  * On success, @data and @data_size will be replaced with variable's
  * actual data, excluding authentication data, and its size, and variable's
  * attributes and signed time will also be returned in @env_attr and @time,
  * respectively.
  *
  * Return:	status code
  */
 static efi_status_t efi_variable_authenticate(u16 *variable,
 					      const efi_guid_t *vendor,
 					      efi_uintn_t *data_size,
 					      const void **data, u32 given_attr,
 					      u32 *env_attr, u64 *time)
 {
 	const struct efi_variable_authentication_2 *auth;
 	struct efi_signature_store *truststore, *truststore2;
 	struct pkcs7_message *var_sig;
 	struct efi_image_regions *regs;
 	struct efi_time timestamp;
 	struct rtc_time tm;
 	u64 new_time;
 	enum efi_auth_var_type var_type;
 	efi_status_t ret;

 	var_sig = NULL;
 	truststore = NULL;
 	truststore2 = NULL;
 	regs = NULL;
 	ret = EFI_SECURITY_VIOLATION;

 	if (*data_size < sizeof(struct efi_variable_authentication_2))
 		goto err;

 	/* authentication data */
 	auth = *data;
 	if (*data_size < (sizeof(auth->time_stamp)
 				+ auth->auth_info.hdr.dwLength))
 		goto err;

 	if (guidcmp(&auth->auth_info.cert_type, &efi_guid_cert_type_pkcs7))
 		goto err;

 	memcpy(&timestamp, &auth->time_stamp, sizeof(timestamp));
 	if (timestamp.pad1 || timestamp.nanosecond || timestamp.timezone ||
 	    timestamp.daylight || timestamp.pad2)
 		goto err;

 	*data += sizeof(auth->time_stamp) + auth->auth_info.hdr.dwLength;
 	*data_size -= (sizeof(auth->time_stamp)
 				+ auth->auth_info.hdr.dwLength);

 	memset(&tm, 0, sizeof(tm));
 	tm.tm_year = timestamp.year;
 	tm.tm_mon = timestamp.month;
 	tm.tm_mday = timestamp.day;
 	tm.tm_hour = timestamp.hour;
 	tm.tm_min = timestamp.minute;
 	tm.tm_sec = timestamp.second;
 	new_time = rtc_mktime(&tm);

 	if (!efi_secure_boot_enabled()) {
 		/* finished checking */
 		*time = new_time;
 		return EFI_SUCCESS;
 	}

 	if (new_time <= *time)
 		goto err;

 	/* data to be digested */
 	regs = calloc(sizeof(*regs) + sizeof(struct image_region) * 5, 1);
 	if (!regs)
 		goto err;
 	regs->max = 5;
 	efi_image_region_add(regs, (uint8_t *)variable,
 			     (uint8_t *)variable
 				+ u16_strlen(variable) * sizeof(u16), 1);
 	efi_image_region_add(regs, (uint8_t *)vendor,
 			     (uint8_t *)vendor + sizeof(*vendor), 1);
 	efi_image_region_add(regs, (uint8_t *)&given_attr,
 			     (uint8_t *)&given_attr + sizeof(given_attr), 1);
 	efi_image_region_add(regs, (uint8_t *)&timestamp,
 			     (uint8_t *)&timestamp + sizeof(timestamp), 1);
 	efi_image_region_add(regs, (uint8_t *)*data,
 			     (uint8_t *)*data + *data_size, 1);

 	/* variable's signature list */
 	if (auth->auth_info.hdr.dwLength < sizeof(auth->auth_info))
 		goto err;
 	var_sig = efi_variable_parse_signature(auth->auth_info.cert_data,
 					       auth->auth_info.hdr.dwLength
 						   - sizeof(auth->auth_info));
 	if (!var_sig) {
 		EFI_PRINT("Parsing variable's signature failed\n");
 		goto err;
 	}

 	/* signature database used for authentication */
 	var_type = efi_auth_var_get_type(variable, vendor);
 	switch (var_type) {
 	case EFI_AUTH_VAR_PK:
 	case EFI_AUTH_VAR_KEK:
 		/* with PK */
 		truststore = efi_sigstore_parse_sigdb(L"PK");
 		if (!truststore)
 			goto err;
 		break;
 	case EFI_AUTH_VAR_DB:
 	case EFI_AUTH_VAR_DBX:
 		/* with PK and KEK */
 		truststore = efi_sigstore_parse_sigdb(L"KEK");
 		truststore2 = efi_sigstore_parse_sigdb(L"PK");
 		if (!truststore) {
 			if (!truststore2)
 				goto err;

 			truststore = truststore2;
 			truststore2 = NULL;
 		}
 		break;
 	default:
 		/* TODO: support private authenticated variables */
 		goto err;
 	}

 	/* verify signature */
 	if (efi_signature_verify_with_sigdb(regs, var_sig, truststore, NULL)) {
 		EFI_PRINT("Verified\n");
 	} else {
 		if (truststore2 &&
 		    efi_signature_verify_with_sigdb(regs, var_sig,
 						    truststore2, NULL)) {
 			EFI_PRINT("Verified\n");
 		} else {
 			EFI_PRINT("Verifying variable's signature failed\n");
 			goto err;
 		}
 	}

 	/* finished checking */
 	*time = new_time;
 	ret = EFI_SUCCESS;

 err:
 	efi_sigstore_free(truststore);
 	efi_sigstore_free(truststore2);
 	pkcs7_free_message(var_sig);
 	free(regs);

 	return ret;
 }
 #else
 static efi_status_t efi_variable_authenticate(u16 *variable,
 					      const efi_guid_t *vendor,
 					      efi_uintn_t *data_size,
 					      const void **data, u32 given_attr,
 					      u32 *env_attr, u64 *time)
 {
 	return EFI_SUCCESS;
 }
 #endif /* CONFIG_EFI_SECURE_BOOT */

 efi_status_t __efi_runtime
 efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor,
 		     u32 *attributes, efi_uintn_t *data_size, void *data,
 		     u64 *timep)
 {
 	efi_uintn_t old_size;
 	struct efi_var_entry *var;
 	u16 *pdata;

 	if (!variable_name || !vendor || !data_size)
 		return EFI_INVALID_PARAMETER;
 	var = efi_var_mem_find(vendor, variable_name, NULL);
 	if (!var)
 		return EFI_NOT_FOUND;

 	if (attributes)
 		*attributes = var->attr;
 	if (timep)
 		*timep = var->time;

 	old_size = *data_size;
 	*data_size = var->length;
 	if (old_size < var->length)
 		return EFI_BUFFER_TOO_SMALL;

 	if (!data)
 		return EFI_INVALID_PARAMETER;

 	for (pdata = var->name; *pdata; ++pdata)
 		;
 	++pdata;

 	efi_memcpy_runtime(data, pdata, var->length);

 	return EFI_SUCCESS;
 }

 efi_status_t __efi_runtime
 efi_get_next_variable_name_int(efi_uintn_t *variable_name_size,
 			       u16 *variable_name, efi_guid_t *vendor)
 {
 	struct efi_var_entry *var;
 	efi_uintn_t old_size;
 	u16 *pdata;

 	if (!variable_name_size || !variable_name || !vendor)
 		return EFI_INVALID_PARAMETER;

 	efi_var_mem_find(vendor, variable_name, &var);

 	if (!var)
 		return EFI_NOT_FOUND;

 	for (pdata = var->name; *pdata; ++pdata)
 		;
 	++pdata;

 	old_size = *variable_name_size;
 	*variable_name_size = (uintptr_t)pdata - (uintptr_t)var->name;

 	if (old_size < *variable_name_size)
 		return EFI_BUFFER_TOO_SMALL;

 	efi_memcpy_runtime(variable_name, var->name, *variable_name_size);
 	efi_memcpy_runtime(vendor, &var->guid, sizeof(efi_guid_t));

 	return EFI_SUCCESS;
 }

 efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor,
 				  u32 attributes, efi_uintn_t data_size,
 				  const void *data, bool ro_check)
 {
 	struct efi_var_entry *var;
 	efi_uintn_t ret;
 	bool append, delete;
 	u64 time = 0;
 	enum efi_auth_var_type var_type;

 	if (!variable_name || !*variable_name || !vendor ||
 	    ((attributes & EFI_VARIABLE_RUNTIME_ACCESS) &&
 	     !(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)))
 		return EFI_INVALID_PARAMETER;

 	/* check if a variable exists */
 	var = efi_var_mem_find(vendor, variable_name, NULL);
 	append = !!(attributes & EFI_VARIABLE_APPEND_WRITE);
 	attributes &= ~(u32)EFI_VARIABLE_APPEND_WRITE;
 	delete = !append && (!data_size || !attributes);

 	/* check attributes */
 	var_type = efi_auth_var_get_type(variable_name, vendor);
 	if (var) {
 		if (ro_check && (var->attr & EFI_VARIABLE_READ_ONLY))
 			return EFI_WRITE_PROTECTED;

 		if (IS_ENABLED(CONFIG_EFI_VARIABLES_PRESEED)) {
 			if (var_type != EFI_AUTH_VAR_NONE)
 				return EFI_WRITE_PROTECTED;
 		}

 		/* attributes won't be changed */
 		if (!delete &&
 		    ((ro_check && var->attr != attributes) ||
 		     (!ro_check && ((var->attr & ~(u32)EFI_VARIABLE_READ_ONLY)
 				    != (attributes & ~(u32)EFI_VARIABLE_READ_ONLY))))) {
 			return EFI_INVALID_PARAMETER;
 		}
 		time = var->time;
 	} else {
 		if (delete || append)
 			/*
 			 * Trying to delete or to update a non-existent
 			 * variable.
 			 */
 			return EFI_NOT_FOUND;
 	}

 	if (var_type != EFI_AUTH_VAR_NONE) {
 		/* authentication is mandatory */
 		if (!(attributes &
 		      EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
 			EFI_PRINT("%ls: TIME_BASED_AUTHENTICATED_WRITE_ACCESS required\n",
 				  variable_name);
 			return EFI_INVALID_PARAMETER;
 		}
 	}

 	/* authenticate a variable */
 	if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) {
 		if (attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
 			return EFI_INVALID_PARAMETER;
 		if (attributes &
 		    EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
 			u32 env_attr;

 			ret = efi_variable_authenticate(variable_name, vendor,
 							&data_size, &data,
 							attributes, &env_attr,
 							&time);
 			if (ret != EFI_SUCCESS)
 				return ret;

 			/* last chance to check for delete */
 			if (!data_size)
 				delete = true;
 		}
 	} else {
 		if (attributes &
 		    (EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS |
 		     EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
 			EFI_PRINT("Secure boot is not configured\n");
 			return EFI_INVALID_PARAMETER;
 		}
 	}

 	if (delete) {
 		/* EFI_NOT_FOUND has been handled before */
 		ret = EFI_SUCCESS;
 	} else if (append) {
 		u16 *old_data = var->name;

 		for (; *old_data; ++old_data)
 			;
 		++old_data;
 		ret = efi_var_mem_ins(variable_name, vendor, attributes,
 				      var->length, old_data, data_size, data,
 				      time);
 	} else {
 		ret = efi_var_mem_ins(variable_name, vendor, attributes,
 				      data_size, data, 0, NULL, time);
 	}
 	efi_var_mem_del(var);

 	if (ret != EFI_SUCCESS)
 		return ret;

 	if (var_type == EFI_AUTH_VAR_PK)
 		ret = efi_init_secure_state();
 	else
 		ret = EFI_SUCCESS;

 	/* Write non-volatile EFI variables to file */
 	if (attributes & EFI_VARIABLE_NON_VOLATILE &&
 	    ret == EFI_SUCCESS && efi_obj_list_initialized == EFI_SUCCESS)
 		efi_var_to_file();

 	return EFI_SUCCESS;
 }

 efi_status_t efi_query_variable_info_int(u32 attributes,
 					 u64 *maximum_variable_storage_size,
 					 u64 *remaining_variable_storage_size,
 					 u64 *maximum_variable_size)
 {
 	*maximum_variable_storage_size = EFI_VAR_BUF_SIZE -
 					 sizeof(struct efi_var_file);
 	*remaining_variable_storage_size = efi_var_mem_free();
 	*maximum_variable_size = EFI_VAR_BUF_SIZE -
 				 sizeof(struct efi_var_file) -
 				 sizeof(struct efi_var_entry);
 	return EFI_SUCCESS;
 }

 /**
  * efi_query_variable_info_runtime() - runtime implementation of
  *				       QueryVariableInfo()
  *
  * @attributes:				bitmask to select variables to be
  *					queried
  * @maximum_variable_storage_size:	maximum size of storage area for the
  *					selected variable types
  * @remaining_variable_storage_size:	remaining size of storage are for the
  *					selected variable types
  * @maximum_variable_size:		maximum size of a variable of the
  *					selected type
  * Returns:				status code
  */
 efi_status_t __efi_runtime EFIAPI efi_query_variable_info_runtime(
 			u32 attributes,
 			u64 *maximum_variable_storage_size,
 			u64 *remaining_variable_storage_size,
 			u64 *maximum_variable_size)
 {
 	return EFI_UNSUPPORTED;
 }

 /**
  * efi_get_variable_runtime() - runtime implementation of GetVariable()
  *
  * @variable_name:	name of the variable
  * @vendor:		vendor GUID
  * @attributes:		attributes of the variable
  * @data_size:		size of the buffer to which the variable value is copied
  * @data:		buffer to which the variable value is copied
  * Return:		status code
  */
 static efi_status_t __efi_runtime EFIAPI
 efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *vendor,
 			 u32 *attributes, efi_uintn_t *data_size, void *data)
 {
 	efi_status_t ret;

 	ret = efi_get_variable_int(variable_name, vendor, attributes,
 				   data_size, data, NULL);

 	/* Remove EFI_VARIABLE_READ_ONLY flag */
 	if (attributes)
 		*attributes &= EFI_VARIABLE_MASK;

 	return ret;
 }

 /**
  * efi_get_next_variable_name_runtime() - runtime implementation of
  *					  GetNextVariable()
  *
  * @variable_name_size:	size of variable_name buffer in byte
  * @variable_name:	name of uefi variable's name in u16
  * @vendor:		vendor's guid
  * Return: status code
  */
 static efi_status_t __efi_runtime EFIAPI
 efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
 				   u16 *variable_name, efi_guid_t *vendor)
 {
 	return efi_get_next_variable_name_int(variable_name_size, variable_name,
 					      vendor);
 }

 /**
  * efi_set_variable_runtime() - runtime implementation of SetVariable()
  *
  * @variable_name:	name of the variable
  * @vendor:		vendor GUID
  * @attributes:		attributes of the variable
  * @data_size:		size of the buffer with the variable value
  * @data:		buffer with the variable value
  * Return:		status code
  */
 static efi_status_t __efi_runtime EFIAPI
 efi_set_variable_runtime(u16 *variable_name, const efi_guid_t *vendor,
 			 u32 attributes, efi_uintn_t data_size,
 			 const void *data)
 {
 	return EFI_UNSUPPORTED;
 }

 /**
  * efi_variables_boot_exit_notify() - notify ExitBootServices() is called
  */
 void efi_variables_boot_exit_notify(void)
 {
 	/* Switch variable services functions to runtime version */
 	efi_runtime_services.get_variable = efi_get_variable_runtime;
 	efi_runtime_services.get_next_variable_name =
 				efi_get_next_variable_name_runtime;
 	efi_runtime_services.set_variable = efi_set_variable_runtime;
 	efi_runtime_services.query_variable_info =
 				efi_query_variable_info_runtime;
 	efi_update_table_header_crc32(&efi_runtime_services.hdr);
 }

 /**
  * efi_init_variables() - initialize variable services
  *
  * Return:	status code
  */
 efi_status_t efi_init_variables(void)
 {
 	efi_status_t ret;

 	ret = efi_var_mem_init();
 	if (ret != EFI_SUCCESS)
 		return ret;

 	ret = efi_init_secure_state();
 	if (ret != EFI_SUCCESS)
 		return ret;

 	if (IS_ENABLED(CONFIG_EFI_VARIABLES_PRESEED)) {
 		ret = efi_var_restore((struct efi_var_file *)
 				      __efi_var_file_begin);
 		if (ret != EFI_SUCCESS)
 			log_err("Invalid EFI variable seed\n");
 	}

 	return efi_var_from_file();
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* UEFI runtime variable services
	*
	* Copyright (c) 2017 Rob Clark
	*/

	#define LOG_CATEGORY LOGC_EFI

	#include <common.h>
	#include <efi_loader.h>
	#include <efi_variable.h>
	#include <env.h>
	#include <env_internal.h>
	#include <hexdump.h>
	#include <log.h>
	#include <malloc.h>
	#include <rtc.h>
	#include <search.h>
	#include <uuid.h>
	#include <crypto/pkcs7_parser.h>
	#include <linux/compat.h>
	#include <u-boot/crc.h>
	#include <asm/sections.h>

	#ifdef CONFIG_EFI_SECURE_BOOT
	static u8 pkcs7_hdr[] = {
	/* SEQUENCE */
	0x30, 0x82, 0x05, 0xc7,
	/* OID: pkcs7-signedData */
	0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x02,
	/* Context Structured? */
	0xa0, 0x82, 0x05, 0xb8,
	};

	/**
	* efi_variable_parse_signature - parse a signature in variable
	* @buf: Pointer to variable's value
	* @buflen: Length of @buf
	*
	* Parse a signature embedded in variable's value and instantiate
	* a pkcs7_message structure. Since pkcs7_parse_message() accepts only
	* pkcs7's signedData, some header needed be prepended for correctly
	* parsing authentication data, particularly for variable's.
	*
	* Return: Pointer to pkcs7_message structure on success, NULL on error
	*/
	static struct pkcs7_message efi_variable_parse_signature(const void buf,
	size_t buflen)
	{
	u8 *ebuf;
	size_t ebuflen, len;
	struct pkcs7_message *msg;

	/*
	* This is the best assumption to check if the binary is
	* already in a form of pkcs7's signedData.
	*/
	if (buflen > sizeof(pkcs7_hdr) &&
	!memcmp(&((u8 *)buf)[4], &pkcs7_hdr[4], 11)) {
	msg = pkcs7_parse_message(buf, buflen);
	goto out;
	}

	/*
	* Otherwise, we should add a dummy prefix sequence for pkcs7
	* message parser to be able to process.
	* NOTE: EDK2 also uses similar hack in WrapPkcs7Data()
	* in CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7VerifyCommon.c
	* TODO:
	* The header should be composed in a more refined manner.
	*/
	EFI_PRINT("Makeshift prefix added to authentication data\n");
	ebuflen = sizeof(pkcs7_hdr) + buflen;
	if (ebuflen <= 0x7f) {
	EFI_PRINT("Data is too short\n");
	return NULL;
	}

	ebuf = malloc(ebuflen);
	if (!ebuf) {
	EFI_PRINT("Out of memory\n");
	return NULL;
	}

	memcpy(ebuf, pkcs7_hdr, sizeof(pkcs7_hdr));
	memcpy(ebuf + sizeof(pkcs7_hdr), buf, buflen);
	len = ebuflen - 4;
	ebuf[2] = (len >> 8) & 0xff;
	ebuf[3] = len & 0xff;
	len = ebuflen - 0x13;
	ebuf[0x11] = (len >> 8) & 0xff;
	ebuf[0x12] = len & 0xff;

	msg = pkcs7_parse_message(ebuf, ebuflen);

	free(ebuf);

	out:
	if (IS_ERR(msg))
	return NULL;

	return msg;
	}

	/**
	* efi_variable_authenticate - authenticate a variable
	* @variable: Variable name in u16
	* @vendor: Guid of variable
	* @data_size: Size of @data
	* @data: Pointer to variable's value
	* @given_attr: Attributes to be given at SetVariable()
	* @env_attr: Attributes that an existing variable holds
	* @time: signed time that an existing variable holds
	*
	* Called by efi_set_variable() to verify that the input is correct.
	* Will replace the given data pointer with another that points to
	* the actual data to store in the internal memory.
	* On success, @data and @data_size will be replaced with variable's
	* actual data, excluding authentication data, and its size, and variable's
	* attributes and signed time will also be returned in @env_attr and @time,
	* respectively.
	*
	* Return: status code
	*/
	static efi_status_t efi_variable_authenticate(u16 *variable,
	const efi_guid_t *vendor,
	efi_uintn_t *data_size,
	const void **data, u32 given_attr,
	u32 env_attr, u64 time)
	{
	const struct efi_variable_authentication_2 *auth;
	struct efi_signature_store truststore, truststore2;
	struct pkcs7_message *var_sig;
	struct efi_image_regions *regs;
	struct efi_time timestamp;
	struct rtc_time tm;
	u64 new_time;
	enum efi_auth_var_type var_type;
	efi_status_t ret;

	var_sig = NULL;
	truststore = NULL;
	truststore2 = NULL;
	regs = NULL;
	ret = EFI_SECURITY_VIOLATION;

	if (*data_size < sizeof(struct efi_variable_authentication_2))
	goto err;

	/* authentication data */
	auth = *data;
	if (*data_size < (sizeof(auth->time_stamp)
	+ auth->auth_info.hdr.dwLength))
	goto err;

	if (guidcmp(&auth->auth_info.cert_type, &efi_guid_cert_type_pkcs7))
	goto err;

	memcpy(&timestamp, &auth->time_stamp, sizeof(timestamp));
	if (timestamp.pad1 \|\| timestamp.nanosecond \|\| timestamp.timezone \|\|
	timestamp.daylight \|\| timestamp.pad2)
	goto err;

	*data += sizeof(auth->time_stamp) + auth->auth_info.hdr.dwLength;
	*data_size -= (sizeof(auth->time_stamp)
	+ auth->auth_info.hdr.dwLength);

	memset(&tm, 0, sizeof(tm));
	tm.tm_year = timestamp.year;
	tm.tm_mon = timestamp.month;
	tm.tm_mday = timestamp.day;
	tm.tm_hour = timestamp.hour;
	tm.tm_min = timestamp.minute;
	tm.tm_sec = timestamp.second;
	new_time = rtc_mktime(&tm);

	if (!efi_secure_boot_enabled()) {
	/* finished checking */
	*time = new_time;
	return EFI_SUCCESS;
	}

	if (new_time <= *time)
	goto err;

	/* data to be digested */
	regs = calloc(sizeof(regs) + sizeof(struct image_region) 5, 1);
	if (!regs)
	goto err;
	regs->max = 5;
	efi_image_region_add(regs, (uint8_t *)variable,
	(uint8_t *)variable
	+ u16_strlen(variable) * sizeof(u16), 1);
	efi_image_region_add(regs, (uint8_t *)vendor,
	(uint8_t )vendor + sizeof(vendor), 1);
	efi_image_region_add(regs, (uint8_t *)&given_attr,
	(uint8_t *)&given_attr + sizeof(given_attr), 1);
	efi_image_region_add(regs, (uint8_t *)&timestamp,
	(uint8_t *)&timestamp + sizeof(timestamp), 1);
	efi_image_region_add(regs, (uint8_t )data,
	(uint8_t )data + *data_size, 1);

	/* variable's signature list */
	if (auth->auth_info.hdr.dwLength < sizeof(auth->auth_info))
	goto err;
	var_sig = efi_variable_parse_signature(auth->auth_info.cert_data,
	auth->auth_info.hdr.dwLength
	- sizeof(auth->auth_info));
	if (!var_sig) {
	EFI_PRINT("Parsing variable's signature failed\n");
	goto err;
	}

	/* signature database used for authentication */
	var_type = efi_auth_var_get_type(variable, vendor);
	switch (var_type) {
	case EFI_AUTH_VAR_PK:
	case EFI_AUTH_VAR_KEK:
	/* with PK */
	truststore = efi_sigstore_parse_sigdb(L"PK");
	if (!truststore)
	goto err;
	break;
	case EFI_AUTH_VAR_DB:
	case EFI_AUTH_VAR_DBX:
	/* with PK and KEK */
	truststore = efi_sigstore_parse_sigdb(L"KEK");
	truststore2 = efi_sigstore_parse_sigdb(L"PK");
	if (!truststore) {
	if (!truststore2)
	goto err;

	truststore = truststore2;
	truststore2 = NULL;
	}
	break;
	default:
	/* TODO: support private authenticated variables */
	goto err;
	}

	/* verify signature */
	if (efi_signature_verify_with_sigdb(regs, var_sig, truststore, NULL)) {
	EFI_PRINT("Verified\n");
	} else {
	if (truststore2 &&
	efi_signature_verify_with_sigdb(regs, var_sig,
	truststore2, NULL)) {
	EFI_PRINT("Verified\n");
	} else {
	EFI_PRINT("Verifying variable's signature failed\n");
	goto err;
	}
	}

	/* finished checking */
	*time = new_time;
	ret = EFI_SUCCESS;

	err:
	efi_sigstore_free(truststore);
	efi_sigstore_free(truststore2);
	pkcs7_free_message(var_sig);
	free(regs);

	return ret;
	}
	#else
	static efi_status_t efi_variable_authenticate(u16 *variable,
	const efi_guid_t *vendor,
	efi_uintn_t *data_size,
	const void **data, u32 given_attr,
	u32 env_attr, u64 time)
	{
	return EFI_SUCCESS;
	}
	#endif /* CONFIG_EFI_SECURE_BOOT */

	efi_status_t __efi_runtime
	efi_get_variable_int(u16 variable_name, const efi_guid_t vendor,
	u32 attributes, efi_uintn_t data_size, void *data,
	u64 *timep)
	{
	efi_uintn_t old_size;
	struct efi_var_entry *var;
	u16 *pdata;

	if (!variable_name \|\| !vendor \|\| !data_size)
	return EFI_INVALID_PARAMETER;
	var = efi_var_mem_find(vendor, variable_name, NULL);
	if (!var)
	return EFI_NOT_FOUND;

	if (attributes)
	*attributes = var->attr;
	if (timep)
	*timep = var->time;

	old_size = *data_size;
	*data_size = var->length;
	if (old_size < var->length)
	return EFI_BUFFER_TOO_SMALL;

	if (!data)
	return EFI_INVALID_PARAMETER;

	for (pdata = var->name; *pdata; ++pdata)
	;
	++pdata;

	efi_memcpy_runtime(data, pdata, var->length);

	return EFI_SUCCESS;
	}

	efi_status_t __efi_runtime
	efi_get_next_variable_name_int(efi_uintn_t *variable_name_size,
	u16 variable_name, efi_guid_t vendor)
	{
	struct efi_var_entry *var;
	efi_uintn_t old_size;
	u16 *pdata;

	if (!variable_name_size \|\| !variable_name \|\| !vendor)
	return EFI_INVALID_PARAMETER;

	efi_var_mem_find(vendor, variable_name, &var);

	if (!var)
	return EFI_NOT_FOUND;

	for (pdata = var->name; *pdata; ++pdata)
	;
	++pdata;

	old_size = *variable_name_size;
	*variable_name_size = (uintptr_t)pdata - (uintptr_t)var->name;

	if (old_size < *variable_name_size)
	return EFI_BUFFER_TOO_SMALL;

	efi_memcpy_runtime(variable_name, var->name, *variable_name_size);
	efi_memcpy_runtime(vendor, &var->guid, sizeof(efi_guid_t));

	return EFI_SUCCESS;
	}

	efi_status_t efi_set_variable_int(u16 variable_name, const efi_guid_t vendor,
	u32 attributes, efi_uintn_t data_size,
	const void *data, bool ro_check)
	{
	struct efi_var_entry *var;
	efi_uintn_t ret;
	bool append, delete;
	u64 time = 0;
	enum efi_auth_var_type var_type;

	if (!variable_name \|\| !*variable_name \|\| !vendor \|\|
	((attributes & EFI_VARIABLE_RUNTIME_ACCESS) &&
	!(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)))
	return EFI_INVALID_PARAMETER;

	/* check if a variable exists */
	var = efi_var_mem_find(vendor, variable_name, NULL);
	append = !!(attributes & EFI_VARIABLE_APPEND_WRITE);
	attributes &= ~(u32)EFI_VARIABLE_APPEND_WRITE;
	delete = !append && (!data_size \|\| !attributes);

	/* check attributes */
	var_type = efi_auth_var_get_type(variable_name, vendor);
	if (var) {
	if (ro_check && (var->attr & EFI_VARIABLE_READ_ONLY))
	return EFI_WRITE_PROTECTED;

	if (IS_ENABLED(CONFIG_EFI_VARIABLES_PRESEED)) {
	if (var_type != EFI_AUTH_VAR_NONE)
	return EFI_WRITE_PROTECTED;
	}

	/* attributes won't be changed */
	if (!delete &&
	((ro_check && var->attr != attributes) \|\|
	(!ro_check && ((var->attr & ~(u32)EFI_VARIABLE_READ_ONLY)
	!= (attributes & ~(u32)EFI_VARIABLE_READ_ONLY))))) {
	return EFI_INVALID_PARAMETER;
	}
	time = var->time;
	} else {
	if (delete \|\| append)
	/*
	* Trying to delete or to update a non-existent
	* variable.
	*/
	return EFI_NOT_FOUND;
	}

	if (var_type != EFI_AUTH_VAR_NONE) {
	/* authentication is mandatory */
	if (!(attributes &
	EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
	EFI_PRINT("%ls: TIME_BASED_AUTHENTICATED_WRITE_ACCESS required\n",
	variable_name);
	return EFI_INVALID_PARAMETER;
	}
	}

	/* authenticate a variable */
	if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) {
	if (attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
	return EFI_INVALID_PARAMETER;
	if (attributes &
	EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
	u32 env_attr;

	ret = efi_variable_authenticate(variable_name, vendor,
	&data_size, &data,
	attributes, &env_attr,
	&time);
	if (ret != EFI_SUCCESS)
	return ret;

	/* last chance to check for delete */
	if (!data_size)
	delete = true;
	}
	} else {
	if (attributes &
	(EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS \|
	EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
	EFI_PRINT("Secure boot is not configured\n");
	return EFI_INVALID_PARAMETER;
	}
	}

	if (delete) {
	/* EFI_NOT_FOUND has been handled before */
	ret = EFI_SUCCESS;
	} else if (append) {
	u16 *old_data = var->name;

	for (; *old_data; ++old_data)
	;
	++old_data;
	ret = efi_var_mem_ins(variable_name, vendor, attributes,
	var->length, old_data, data_size, data,
	time);
	} else {
	ret = efi_var_mem_ins(variable_name, vendor, attributes,
	data_size, data, 0, NULL, time);
	}
	efi_var_mem_del(var);

	if (ret != EFI_SUCCESS)
	return ret;

	if (var_type == EFI_AUTH_VAR_PK)
	ret = efi_init_secure_state();
	else
	ret = EFI_SUCCESS;

	/* Write non-volatile EFI variables to file */
	if (attributes & EFI_VARIABLE_NON_VOLATILE &&
	ret == EFI_SUCCESS && efi_obj_list_initialized == EFI_SUCCESS)
	efi_var_to_file();

	return EFI_SUCCESS;
	}

	efi_status_t efi_query_variable_info_int(u32 attributes,
	u64 *maximum_variable_storage_size,
	u64 *remaining_variable_storage_size,
	u64 *maximum_variable_size)
	{
	*maximum_variable_storage_size = EFI_VAR_BUF_SIZE -
	sizeof(struct efi_var_file);
	*remaining_variable_storage_size = efi_var_mem_free();
	*maximum_variable_size = EFI_VAR_BUF_SIZE -
	sizeof(struct efi_var_file) -
	sizeof(struct efi_var_entry);
	return EFI_SUCCESS;
	}

	/**
	* efi_query_variable_info_runtime() - runtime implementation of
	* QueryVariableInfo()
	*
	* @attributes: bitmask to select variables to be
	* queried
	* @maximum_variable_storage_size: maximum size of storage area for the
	* selected variable types
	* @remaining_variable_storage_size: remaining size of storage are for the
	* selected variable types
	* @maximum_variable_size: maximum size of a variable of the
	* selected type
	* Returns: status code
	*/
	efi_status_t __efi_runtime EFIAPI efi_query_variable_info_runtime(
	u32 attributes,
	u64 *maximum_variable_storage_size,
	u64 *remaining_variable_storage_size,
	u64 *maximum_variable_size)
	{
	return EFI_UNSUPPORTED;
	}

	/**
	* efi_get_variable_runtime() - runtime implementation of GetVariable()
	*
	* @variable_name: name of the variable
	* @vendor: vendor GUID
	* @attributes: attributes of the variable
	* @data_size: size of the buffer to which the variable value is copied
	* @data: buffer to which the variable value is copied
	* Return: status code
	*/
	static efi_status_t __efi_runtime EFIAPI
	efi_get_variable_runtime(u16 variable_name, const efi_guid_t vendor,
	u32 attributes, efi_uintn_t data_size, void *data)
	{
	efi_status_t ret;

	ret = efi_get_variable_int(variable_name, vendor, attributes,
	data_size, data, NULL);

	/* Remove EFI_VARIABLE_READ_ONLY flag */
	if (attributes)
	*attributes &= EFI_VARIABLE_MASK;

	return ret;
	}

	/**
	* efi_get_next_variable_name_runtime() - runtime implementation of
	* GetNextVariable()
	*
	* @variable_name_size: size of variable_name buffer in byte
	* @variable_name: name of uefi variable's name in u16
	* @vendor: vendor's guid
	* Return: status code
	*/
	static efi_status_t __efi_runtime EFIAPI
	efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
	u16 variable_name, efi_guid_t vendor)
	{
	return efi_get_next_variable_name_int(variable_name_size, variable_name,
	vendor);
	}

	/**
	* efi_set_variable_runtime() - runtime implementation of SetVariable()
	*
	* @variable_name: name of the variable
	* @vendor: vendor GUID
	* @attributes: attributes of the variable
	* @data_size: size of the buffer with the variable value
	* @data: buffer with the variable value
	* Return: status code
	*/
	static efi_status_t __efi_runtime EFIAPI
	efi_set_variable_runtime(u16 variable_name, const efi_guid_t vendor,
	u32 attributes, efi_uintn_t data_size,
	const void *data)
	{
	return EFI_UNSUPPORTED;
	}

	/**
	* efi_variables_boot_exit_notify() - notify ExitBootServices() is called
	*/
	void efi_variables_boot_exit_notify(void)
	{
	/* Switch variable services functions to runtime version */
	efi_runtime_services.get_variable = efi_get_variable_runtime;
	efi_runtime_services.get_next_variable_name =
	efi_get_next_variable_name_runtime;
	efi_runtime_services.set_variable = efi_set_variable_runtime;
	efi_runtime_services.query_variable_info =
	efi_query_variable_info_runtime;
	efi_update_table_header_crc32(&efi_runtime_services.hdr);
	}

	/**
	* efi_init_variables() - initialize variable services
	*
	* Return: status code
	*/
	efi_status_t efi_init_variables(void)
	{
	efi_status_t ret;

	ret = efi_var_mem_init();
	if (ret != EFI_SUCCESS)
	return ret;

	ret = efi_init_secure_state();
	if (ret != EFI_SUCCESS)
	return ret;

	if (IS_ENABLED(CONFIG_EFI_VARIABLES_PRESEED)) {
	ret = efi_var_restore((struct efi_var_file *)
	__efi_var_file_begin);
	if (ret != EFI_SUCCESS)
	log_err("Invalid EFI variable seed\n");
	}

	return efi_var_from_file();
	}