cmd/nvedit_efi.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *  Integrate UEFI variables to u-boot env interface
 *
 *  Copyright (c) 2018 AKASHI Takahiro, Linaro Limited
 */

#include <charset.h>
#include <common.h>
#include <command.h>
#include <efi_loader.h>
#include <exports.h>
#include <hexdump.h>
#include <malloc.h>
#include <linux/kernel.h>

/*
 * From efi_variable.c,
 *
 * Mapping between UEFI variables and u-boot variables:
 *
 *   efi_$guid_$varname = {attributes}(type)value
 */

static const struct {
	u32 mask;
	char *text;
} efi_var_attrs[] = {
	{EFI_VARIABLE_NON_VOLATILE, "NV"},
	{EFI_VARIABLE_BOOTSERVICE_ACCESS, "BS"},
	{EFI_VARIABLE_RUNTIME_ACCESS, "RT"},
	{EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS, "AW"},
	{EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS, "AT"},
};

/**
 * efi_dump_single_var() - show information about a UEFI variable
 *
 * @name:	Name of the variable
 * @guid:	Vendor GUID
 *
 * Show information encoded in one UEFI variable
 */
static void efi_dump_single_var(u16 *name, efi_guid_t *guid)
{
	u32 attributes;
	u8 *data;
	efi_uintn_t size;
	int count, i;
	efi_status_t ret;

	data = NULL;
	size = 0;
	ret = EFI_CALL(efi_get_variable(name, guid, &attributes, &size, data));
	if (ret == EFI_BUFFER_TOO_SMALL) {
		data = malloc(size);
		if (!data)
			goto out;

		ret = EFI_CALL(efi_get_variable(name, guid, &attributes, &size,
						data));
	}
	if (ret == EFI_NOT_FOUND) {
		printf("Error: \"%ls\" not defined\n", name);
		goto out;
	}
	if (ret != EFI_SUCCESS)
		goto out;

	printf("%ls:", name);
	for (count = 0, i = 0; i < ARRAY_SIZE(efi_var_attrs); i++)
		if (attributes & efi_var_attrs[i].mask) {
			if (count)
				putc('|');
			else
				putc(' ');
			count++;
			puts(efi_var_attrs[i].text);
		}
	printf(", DataSize = 0x%zx\n", size);
	print_hex_dump("    ", DUMP_PREFIX_OFFSET, 16, 1, data, size, true);

out:
	free(data);
}

/**
 * efi_dump_vars() - show information about named UEFI variables
 *
 * @argc:	Number of arguments (variables)
 * @argv:	Argument (variable name) array
 * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
 *
 * Show information encoded in named UEFI variables
 */
static int efi_dump_vars(int argc,  char * const argv[])
{
	u16 *var_name16, *p;
	efi_uintn_t buf_size, size;

	buf_size = 128;
	var_name16 = malloc(buf_size);
	if (!var_name16)
		return CMD_RET_FAILURE;

	for (; argc > 0; argc--, argv++) {
		size = (utf8_utf16_strlen(argv[0]) + 1) * sizeof(u16);
		if (buf_size < size) {
			buf_size = size;
			p = realloc(var_name16, buf_size);
			if (!p) {
				free(var_name16);
				return CMD_RET_FAILURE;
			}
			var_name16 = p;
		}

		p = var_name16;
		utf8_utf16_strcpy(&p, argv[0]);

		efi_dump_single_var(var_name16,
				    (efi_guid_t *)&efi_global_variable_guid);
	}

	free(var_name16);

	return CMD_RET_SUCCESS;
}

/**
 * efi_dump_vars() - show information about all the UEFI variables
 *
 * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
 *
 * Show information encoded in all the UEFI variables
 */
static int efi_dump_var_all(void)
{
	u16 *var_name16, *p;
	efi_uintn_t buf_size, size;
	efi_guid_t guid;
	efi_status_t ret;

	buf_size = 128;
	var_name16 = malloc(buf_size);
	if (!var_name16)
		return CMD_RET_FAILURE;

	var_name16[0] = 0;
	for (;;) {
		size = buf_size;
		ret = EFI_CALL(efi_get_next_variable_name(&size, var_name16,
							  &guid));
		if (ret == EFI_NOT_FOUND)
			break;
		if (ret == EFI_BUFFER_TOO_SMALL) {
			buf_size = size;
			p = realloc(var_name16, buf_size);
			if (!p) {
				free(var_name16);
				return CMD_RET_FAILURE;
			}
			var_name16 = p;
			ret = EFI_CALL(efi_get_next_variable_name(&size,
								  var_name16,
								  &guid));
		}
		if (ret != EFI_SUCCESS) {
			free(var_name16);
			return CMD_RET_FAILURE;
		}

		efi_dump_single_var(var_name16, &guid);
	}

	free(var_name16);

	return CMD_RET_SUCCESS;
}

/**
 * do_env_print_efi() - show information about UEFI variables
 *
 * @cmdtp:	Command table
 * @flag:	Command flag
 * @argc:	Number of arguments
 * @argv:	Argument array
 * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
 *
 * This function is for "env print -e" or "printenv -e" command:
 *   => env print -e [var [...]]
 * If one or more variable names are specified, show information
 * named UEFI variables, otherwise show all the UEFI variables.
 */
int do_env_print_efi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
	efi_status_t ret;

	/* Initialize EFI drivers */
	ret = efi_init_obj_list();
	if (ret != EFI_SUCCESS) {
		printf("Error: Cannot initialize UEFI sub-system, r = %lu\n",
		       ret & ~EFI_ERROR_MASK);
		return CMD_RET_FAILURE;
	}

	if (argc > 1)
		/* show specified UEFI variables */
		return efi_dump_vars(--argc, ++argv);

	/* enumerate and show all UEFI variables */
	return efi_dump_var_all();
}

/**
 * append_value() - encode UEFI variable's value
 * @bufp:	Buffer of encoded UEFI variable's value
 * @sizep:	Size of buffer
 * @data:	data to be encoded into the value
 * Return:	0 on success, -1 otherwise
 *
 * Interpret a given data string and append it to buffer.
 * Buffer will be realloc'ed if necessary.
 *
 * Currently supported formats are:
 *   =0x0123...:		Hexadecimal number
 *   =H0123...:			Hexadecimal-byte array
 *   ="...", =S"..." or <string>:
 *				String
 */
static int append_value(char **bufp, size_t *sizep, char *data)
{
	char *tmp_buf = NULL, *new_buf = NULL, *value;
	unsigned long len = 0;

	if (!strncmp(data, "=0x", 2)) { /* hexadecimal number */
		union {
			u8 u8;
			u16 u16;
			u32 u32;
			u64 u64;
		} tmp_data;
		unsigned long hex_value;
		void *hex_ptr;

		data += 3;
		len = strlen(data);
		if ((len & 0x1)) /* not multiple of two */
			return -1;

		len /= 2;
		if (len > 8)
			return -1;
		else if (len > 4)
			len = 8;
		else if (len > 2)
			len = 4;

		/* convert hex hexadecimal number */
		if (strict_strtoul(data, 16, &hex_value) < 0)
			return -1;

		tmp_buf = malloc(len);
		if (!tmp_buf)
			return -1;

		if (len == 1) {
			tmp_data.u8 = hex_value;
			hex_ptr = &tmp_data.u8;
		} else if (len == 2) {
			tmp_data.u16 = hex_value;
			hex_ptr = &tmp_data.u16;
		} else if (len == 4) {
			tmp_data.u32 = hex_value;
			hex_ptr = &tmp_data.u32;
		} else {
			tmp_data.u64 = hex_value;
			hex_ptr = &tmp_data.u64;
		}
		memcpy(tmp_buf, hex_ptr, len);
		value = tmp_buf;

	} else if (!strncmp(data, "=H", 2)) { /* hexadecimal-byte array */
		data += 2;
		len = strlen(data);
		if (len & 0x1) /* not multiple of two */
			return -1;

		len /= 2;
		tmp_buf = malloc(len);
		if (!tmp_buf)
			return -1;

		if (hex2bin((u8 *)tmp_buf, data, len) < 0) {
			printf("Error: illegal hexadecimal string\n");
			free(tmp_buf);
			return -1;
		}

		value = tmp_buf;
	} else { /* string */
		if (!strncmp(data, "=\"", 2) || !strncmp(data, "=S\"", 3)) {
			if (data[1] == '"')
				data += 2;
			else
				data += 3;
			value = data;
			len = strlen(data) - 1;
			if (data[len] != '"')
				return -1;
		} else {
			value = data;
			len = strlen(data);
		}
	}

	new_buf = realloc(*bufp, *sizep + len);
	if (!new_buf)
		goto out;

	memcpy(new_buf + *sizep, value, len);
	*bufp = new_buf;
	*sizep += len;

out:
	free(tmp_buf);

	return 0;
}

/**
 * do_env_print_efi() - set UEFI variable
 *
 * @cmdtp:	Command table
 * @flag:	Command flag
 * @argc:	Number of arguments
 * @argv:	Argument array
 * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
 *
 * This function is for "env set -e" or "setenv -e" command:
 *   => env set -e var [value ...]]
 * Encode values specified and set given UEFI variable.
 * If no value is specified, delete the variable.
 */
int do_env_set_efi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
	char *var_name, *value = NULL;
	efi_uintn_t size = 0;
	u16 *var_name16 = NULL, *p;
	size_t len;
	efi_guid_t guid;
	efi_status_t ret;

	if (argc == 1)
		return CMD_RET_USAGE;

	/* Initialize EFI drivers */
	ret = efi_init_obj_list();
	if (ret != EFI_SUCCESS) {
		printf("Error: Cannot initialize UEFI sub-system, r = %lu\n",
		       ret & ~EFI_ERROR_MASK);
		return CMD_RET_FAILURE;
	}

	var_name = argv[1];
	if (argc == 2) {
		/* delete */
		value = NULL;
		size = 0;
	} else { /* set */
		argc -= 2;
		argv += 2;

		for ( ; argc > 0; argc--, argv++)
			if (append_value(&value, &size, argv[0]) < 0) {
				ret = CMD_RET_FAILURE;
				goto out;
			}
	}

	len = utf8_utf16_strnlen(var_name, strlen(var_name));
	var_name16 = malloc((len + 1) * 2);
	if (!var_name16) {
		ret = CMD_RET_FAILURE;
		goto out;
	}
	p = var_name16;
	utf8_utf16_strncpy(&p, var_name, len + 1);

	guid = efi_global_variable_guid;
	ret = EFI_CALL(efi_set_variable(var_name16, &guid,
					EFI_VARIABLE_BOOTSERVICE_ACCESS |
					EFI_VARIABLE_RUNTIME_ACCESS,
					size, value));
	ret = (ret == EFI_SUCCESS ? CMD_RET_SUCCESS : CMD_RET_FAILURE);
out:
	free(value);
	free(var_name16);

	return ret;
}