lib/efi_loader/efi_var_mem.c - u-boot - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * File interface for UEFI variables
  *
  * Copyright (c) 2020, Heinrich Schuchardt
  */

 #include <common.h>
 #include <efi_loader.h>
 #include <efi_variable.h>
 #include <u-boot/crc.h>

 /*
  * The variables efi_var_file and efi_var_entry must be static to avoid
  * referencing them via the global offset table (section .got). The GOT
  * is neither mapped as EfiRuntimeServicesData nor do we support its
  * relocation during SetVirtualAddressMap().
  */
 static struct efi_var_file __efi_runtime_data *efi_var_buf;
 static struct efi_var_entry __efi_runtime_data *efi_current_var;

 /**
  * efi_var_mem_compare() - compare GUID and name with a variable
  *
  * @var:	variable to compare
  * @guid:	GUID to compare
  * @name:	variable name to compare
  * @next:	pointer to next variable
  * Return:	true if match
  */
 static bool __efi_runtime
 efi_var_mem_compare(struct efi_var_entry *var, const efi_guid_t *guid,
 		    const u16 *name, struct efi_var_entry **next)
 {
 	int i;
 	u8 *guid1, *guid2;
 	const u16 *data, *var_name;
 	bool match = true;

 	for (guid1 = (u8 *)&var->guid, guid2 = (u8 *)guid, i = 0;
 	     i < sizeof(efi_guid_t) && match; ++i)
 		match = (guid1[i] == guid2[i]);

 	for (data = var->name, var_name = name;; ++data) {
 		if (match)
 			match = (*data == *var_name);
 		if (!*data)
 			break;
 		if (*var_name)
 			++var_name;
 	}

 	++data;

 	if (next)
 		*next = (struct efi_var_entry *)
 			ALIGN((uintptr_t)data + var->length, 8);

 	if (match)
 		efi_current_var = var;

 	return match;
 }

 struct efi_var_entry __efi_runtime
 *efi_var_mem_find(const efi_guid_t *guid, const u16 *name,
 		  struct efi_var_entry **next)
 {
 	struct efi_var_entry *var, *last;

 	last = (struct efi_var_entry *)
 	       ((uintptr_t)efi_var_buf + efi_var_buf->length);

 	if (!*name) {
 		if (next) {
 			*next = efi_var_buf->var;
 			if (*next >= last)
 				*next = NULL;
 		}
 		return NULL;
 	}
 	if (efi_current_var &&
 	    efi_var_mem_compare(efi_current_var, guid, name, next)) {
 		if (next && *next >= last)
 			*next = NULL;
 		return efi_current_var;
 	}

 	var = efi_var_buf->var;
 	if (var < last) {
 		for (; var;) {
 			struct efi_var_entry *pos;
 			bool match;

 			match = efi_var_mem_compare(var, guid, name, &pos);
 			if (pos >= last)
 				pos = NULL;
 			if (match) {
 				if (next)
 					*next = pos;
 				return var;
 			}
 			var = pos;
 		}
 	}
 	if (next)
 		*next = NULL;
 	return NULL;
 }

 void __efi_runtime efi_var_mem_del(struct efi_var_entry *var)
 {
 	u16 *data;
 	struct efi_var_entry *next, *last;

 	if (!var)
 		return;

 	last = (struct efi_var_entry *)
 	       ((uintptr_t)efi_var_buf + efi_var_buf->length);
 	if (var <= efi_current_var)
 		efi_current_var = NULL;

 	for (data = var->name; *data; ++data)
 		;
 	++data;
 	next = (struct efi_var_entry *)
 	       ALIGN((uintptr_t)data + var->length, 8);
 	efi_var_buf->length -= (uintptr_t)next - (uintptr_t)var;

 	/* efi_memcpy_runtime() can be used because next >= var. */
 	efi_memcpy_runtime(var, next, (uintptr_t)last - (uintptr_t)next);
 	efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
 				   efi_var_buf->length -
 				   sizeof(struct efi_var_file));
 }

 efi_status_t __efi_runtime efi_var_mem_ins(
 				const u16 *variable_name,
 				const efi_guid_t *vendor, u32 attributes,
 				const efi_uintn_t size1, const void *data1,
 				const efi_uintn_t size2, const void *data2,
 				const u64 time)
 {
 	u16 *data;
 	struct efi_var_entry *var;
 	u32 var_name_len;

 	var = (struct efi_var_entry *)
 	      ((uintptr_t)efi_var_buf + efi_var_buf->length);
 	var_name_len = u16_strlen(variable_name) + 1;
 	data = var->name + var_name_len;

 	if ((uintptr_t)data - (uintptr_t)efi_var_buf + size1 + size2 >
 	    EFI_VAR_BUF_SIZE)
 		return EFI_OUT_OF_RESOURCES;

 	var->attr = attributes;
 	var->length = size1 + size2;
 	var->time = time;

 	efi_memcpy_runtime(&var->guid, vendor, sizeof(efi_guid_t));
 	efi_memcpy_runtime(var->name, variable_name,
 			   sizeof(u16) * var_name_len);
 	efi_memcpy_runtime(data, data1, size1);
 	efi_memcpy_runtime((u8 *)data + size1, data2, size2);

 	var = (struct efi_var_entry *)
 	      ALIGN((uintptr_t)data + var->length, 8);
 	efi_var_buf->length = (uintptr_t)var - (uintptr_t)efi_var_buf;
 	efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
 				   efi_var_buf->length -
 				   sizeof(struct efi_var_file));

 	return EFI_SUCCESS;
 }

 u64 __efi_runtime efi_var_mem_free(void)
 {
 	return EFI_VAR_BUF_SIZE - efi_var_buf->length -
 	       sizeof(struct efi_var_entry);
 }

 /**
  * efi_var_mem_bs_del() - delete boot service only variables
  */
 static void efi_var_mem_bs_del(void)
 {
 	struct efi_var_entry *var = efi_var_buf->var;

 	for (;;) {
 		struct efi_var_entry *last;

 		last = (struct efi_var_entry *)
 		       ((uintptr_t)efi_var_buf + efi_var_buf->length);
 		if (var >= last)
 			break;
 		if (var->attr & EFI_VARIABLE_RUNTIME_ACCESS) {
 			u16 *data;

 			/* skip variable */
 			for (data = var->name; *data; ++data)
 				;
 			++data;
 			var = (struct efi_var_entry *)
 			      ALIGN((uintptr_t)data + var->length, 8);
 		} else {
 			/* delete variable */
 			efi_var_mem_del(var);
 		}
 	}
 }

 /**
  * efi_var_mem_notify_exit_boot_services() - ExitBootService callback
  *
  * @event:	callback event
  * @context:	callback context
  */
 static void EFIAPI
 efi_var_mem_notify_exit_boot_services(struct efi_event *event, void *context)
 {
 	EFI_ENTRY("%p, %p", event, context);

 	/* Delete boot service only variables */
 	efi_var_mem_bs_del();

 	EFI_EXIT(EFI_SUCCESS);
 }

 /**
  * efi_var_mem_notify_exit_boot_services() - SetVirtualMemoryMap callback
  *
  * @event:	callback event
  * @context:	callback context
  */
 static void EFIAPI __efi_runtime
 efi_var_mem_notify_virtual_address_map(struct efi_event *event, void *context)
 {
 	efi_convert_pointer(0, (void **)&efi_var_buf);
 	efi_current_var = NULL;
 }

 efi_status_t efi_var_mem_init(void)
 {
 	u64 memory;
 	efi_status_t ret;
 	struct efi_event *event;

 	ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
 				 EFI_RUNTIME_SERVICES_DATA,
 				 efi_size_in_pages(EFI_VAR_BUF_SIZE),
 				 &memory);
 	if (ret != EFI_SUCCESS)
 		return ret;
 	efi_var_buf = (struct efi_var_file *)(uintptr_t)memory;
 	memset(efi_var_buf, 0, EFI_VAR_BUF_SIZE);
 	efi_var_buf->magic = EFI_VAR_FILE_MAGIC;
 	efi_var_buf->length = (uintptr_t)efi_var_buf->var -
 			      (uintptr_t)efi_var_buf;
 	/* crc32 for 0 bytes = 0 */

 	ret = efi_create_event(EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
 			       efi_var_mem_notify_exit_boot_services, NULL,
 			       NULL, &event);
 	if (ret != EFI_SUCCESS)
 		return ret;
 	ret = efi_create_event(EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE, TPL_CALLBACK,
 			       efi_var_mem_notify_virtual_address_map, NULL,
 			       NULL, &event);
 	if (ret != EFI_SUCCESS)
 		return ret;
 	return ret;
 }

 efi_status_t __efi_runtime
 efi_get_variable_mem(const 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_mem(efi_uintn_t *variable_name_size,
 			       u16 *variable_name, efi_guid_t *vendor)
 {
 	struct efi_var_entry *var;
 	efi_uintn_t len, old_size;
 	u16 *pdata;

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

 	len = *variable_name_size >> 1;
 	if (u16_strnlen(variable_name, len) == len)
 		return EFI_INVALID_PARAMETER;

 	if (!efi_var_mem_find(vendor, variable_name, &var) && *variable_name)
 		return EFI_INVALID_PARAMETER;

 	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;
 }

 void efi_var_buf_update(struct efi_var_file *var_buf)
 {
 	memcpy(efi_var_buf, var_buf, EFI_VAR_BUF_SIZE);
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* File interface for UEFI variables
	*
	* Copyright (c) 2020, Heinrich Schuchardt
	*/

	#include <common.h>
	#include <efi_loader.h>
	#include <efi_variable.h>
	#include <u-boot/crc.h>

	/*
	* The variables efi_var_file and efi_var_entry must be static to avoid
	* referencing them via the global offset table (section .got). The GOT
	* is neither mapped as EfiRuntimeServicesData nor do we support its
	* relocation during SetVirtualAddressMap().
	*/
	static struct efi_var_file __efi_runtime_data *efi_var_buf;
	static struct efi_var_entry __efi_runtime_data *efi_current_var;

	/**
	* efi_var_mem_compare() - compare GUID and name with a variable
	*
	* @var: variable to compare
	* @guid: GUID to compare
	* @name: variable name to compare
	* @next: pointer to next variable
	* Return: true if match
	*/
	static bool __efi_runtime
	efi_var_mem_compare(struct efi_var_entry var, const efi_guid_t guid,
	const u16 name, struct efi_var_entry *next)
	{
	int i;
	u8 guid1, guid2;
	const u16 data, var_name;
	bool match = true;

	for (guid1 = (u8 )&var->guid, guid2 = (u8 )guid, i = 0;
	i < sizeof(efi_guid_t) && match; ++i)
	match = (guid1[i] == guid2[i]);

	for (data = var->name, var_name = name;; ++data) {
	if (match)
	match = (data == var_name);
	if (!*data)
	break;
	if (*var_name)
	++var_name;
	}

	++data;

	if (next)
	next = (struct efi_var_entry )
	ALIGN((uintptr_t)data + var->length, 8);

	if (match)
	efi_current_var = var;

	return match;
	}

	struct efi_var_entry __efi_runtime
	efi_var_mem_find(const efi_guid_t guid, const u16 *name,
	struct efi_var_entry **next)
	{
	struct efi_var_entry var, last;

	last = (struct efi_var_entry *)
	((uintptr_t)efi_var_buf + efi_var_buf->length);

	if (!*name) {
	if (next) {
	*next = efi_var_buf->var;
	if (*next >= last)
	*next = NULL;
	}
	return NULL;
	}
	if (efi_current_var &&
	efi_var_mem_compare(efi_current_var, guid, name, next)) {
	if (next && *next >= last)
	*next = NULL;
	return efi_current_var;
	}

	var = efi_var_buf->var;
	if (var < last) {
	for (; var;) {
	struct efi_var_entry *pos;
	bool match;

	match = efi_var_mem_compare(var, guid, name, &pos);
	if (pos >= last)
	pos = NULL;
	if (match) {
	if (next)
	*next = pos;
	return var;
	}
	var = pos;
	}
	}
	if (next)
	*next = NULL;
	return NULL;
	}

	void __efi_runtime efi_var_mem_del(struct efi_var_entry *var)
	{
	u16 *data;
	struct efi_var_entry next, last;

	if (!var)
	return;

	last = (struct efi_var_entry *)
	((uintptr_t)efi_var_buf + efi_var_buf->length);
	if (var <= efi_current_var)
	efi_current_var = NULL;

	for (data = var->name; *data; ++data)
	;
	++data;
	next = (struct efi_var_entry *)
	ALIGN((uintptr_t)data + var->length, 8);
	efi_var_buf->length -= (uintptr_t)next - (uintptr_t)var;

	/* efi_memcpy_runtime() can be used because next >= var. */
	efi_memcpy_runtime(var, next, (uintptr_t)last - (uintptr_t)next);
	efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
	efi_var_buf->length -
	sizeof(struct efi_var_file));
	}

	efi_status_t __efi_runtime efi_var_mem_ins(
	const u16 *variable_name,
	const efi_guid_t *vendor, u32 attributes,
	const efi_uintn_t size1, const void *data1,
	const efi_uintn_t size2, const void *data2,
	const u64 time)
	{
	u16 *data;
	struct efi_var_entry *var;
	u32 var_name_len;

	var = (struct efi_var_entry *)
	((uintptr_t)efi_var_buf + efi_var_buf->length);
	var_name_len = u16_strlen(variable_name) + 1;
	data = var->name + var_name_len;

	if ((uintptr_t)data - (uintptr_t)efi_var_buf + size1 + size2 >
	EFI_VAR_BUF_SIZE)
	return EFI_OUT_OF_RESOURCES;

	var->attr = attributes;
	var->length = size1 + size2;
	var->time = time;

	efi_memcpy_runtime(&var->guid, vendor, sizeof(efi_guid_t));
	efi_memcpy_runtime(var->name, variable_name,
	sizeof(u16) * var_name_len);
	efi_memcpy_runtime(data, data1, size1);
	efi_memcpy_runtime((u8 *)data + size1, data2, size2);

	var = (struct efi_var_entry *)
	ALIGN((uintptr_t)data + var->length, 8);
	efi_var_buf->length = (uintptr_t)var - (uintptr_t)efi_var_buf;
	efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
	efi_var_buf->length -
	sizeof(struct efi_var_file));

	return EFI_SUCCESS;
	}

	u64 __efi_runtime efi_var_mem_free(void)
	{
	return EFI_VAR_BUF_SIZE - efi_var_buf->length -
	sizeof(struct efi_var_entry);
	}

	/**
	* efi_var_mem_bs_del() - delete boot service only variables
	*/
	static void efi_var_mem_bs_del(void)
	{
	struct efi_var_entry *var = efi_var_buf->var;

	for (;;) {
	struct efi_var_entry *last;

	last = (struct efi_var_entry *)
	((uintptr_t)efi_var_buf + efi_var_buf->length);
	if (var >= last)
	break;
	if (var->attr & EFI_VARIABLE_RUNTIME_ACCESS) {
	u16 *data;

	/* skip variable */
	for (data = var->name; *data; ++data)
	;
	++data;
	var = (struct efi_var_entry *)
	ALIGN((uintptr_t)data + var->length, 8);
	} else {
	/* delete variable */
	efi_var_mem_del(var);
	}
	}
	}

	/**
	* efi_var_mem_notify_exit_boot_services() - ExitBootService callback
	*
	* @event: callback event
	* @context: callback context
	*/
	static void EFIAPI
	efi_var_mem_notify_exit_boot_services(struct efi_event event, void context)
	{
	EFI_ENTRY("%p, %p", event, context);

	/* Delete boot service only variables */
	efi_var_mem_bs_del();

	EFI_EXIT(EFI_SUCCESS);
	}

	/**
	* efi_var_mem_notify_exit_boot_services() - SetVirtualMemoryMap callback
	*
	* @event: callback event
	* @context: callback context
	*/
	static void EFIAPI __efi_runtime
	efi_var_mem_notify_virtual_address_map(struct efi_event event, void context)
	{
	efi_convert_pointer(0, (void **)&efi_var_buf);
	efi_current_var = NULL;
	}

	efi_status_t efi_var_mem_init(void)
	{
	u64 memory;
	efi_status_t ret;
	struct efi_event *event;

	ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
	EFI_RUNTIME_SERVICES_DATA,
	efi_size_in_pages(EFI_VAR_BUF_SIZE),
	&memory);
	if (ret != EFI_SUCCESS)
	return ret;
	efi_var_buf = (struct efi_var_file *)(uintptr_t)memory;
	memset(efi_var_buf, 0, EFI_VAR_BUF_SIZE);
	efi_var_buf->magic = EFI_VAR_FILE_MAGIC;
	efi_var_buf->length = (uintptr_t)efi_var_buf->var -
	(uintptr_t)efi_var_buf;
	/* crc32 for 0 bytes = 0 */

	ret = efi_create_event(EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
	efi_var_mem_notify_exit_boot_services, NULL,
	NULL, &event);
	if (ret != EFI_SUCCESS)
	return ret;
	ret = efi_create_event(EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE, TPL_CALLBACK,
	efi_var_mem_notify_virtual_address_map, NULL,
	NULL, &event);
	if (ret != EFI_SUCCESS)
	return ret;
	return ret;
	}

	efi_status_t __efi_runtime
	efi_get_variable_mem(const 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_mem(efi_uintn_t *variable_name_size,
	u16 variable_name, efi_guid_t vendor)
	{
	struct efi_var_entry *var;
	efi_uintn_t len, old_size;
	u16 *pdata;

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

	len = *variable_name_size >> 1;
	if (u16_strnlen(variable_name, len) == len)
	return EFI_INVALID_PARAMETER;

	if (!efi_var_mem_find(vendor, variable_name, &var) && *variable_name)
	return EFI_INVALID_PARAMETER;

	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;
	}

	void efi_var_buf_update(struct efi_var_file *var_buf)
	{
	memcpy(efi_var_buf, var_buf, EFI_VAR_BUF_SIZE);
	}