path: root/futility/updater.c

/*
 * Copyright 2018 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 *
 * A reference implementation for AP (and supporting images) firmware updater.
 */

#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "2rsa.h"
#include "2common.h"
#include "crossystem.h"
#include "fmap.h"
#include "futility.h"
#include "host_misc.h"
#include "updater.h"
#include "utility.h"
#include "util_misc.h"
#include "vb2_common.h"
#include "vb2_struct.h"

#define COMMAND_BUFFER_SIZE 256
#define RETURN_ON_FAILURE(x) do {int r = (x); if (r) return r;} while (0);
#define FLASHROM_OUTPUT_WP_PATTERN "write protect is "
#define REMOVE_WP_URL "https://goo.gl/ces83U"

/* System environment values. */
static const char * const FWACT_A = "A",
		  * const FWACT_B = "B",
		  * const STR_REV = "rev",
		  * const FLASHROM_OUTPUT_WP_ENABLED =
			  FLASHROM_OUTPUT_WP_PATTERN "enabled",
		  * const FLASHROM_OUTPUT_WP_DISABLED =
			  FLASHROM_OUTPUT_WP_PATTERN "disabled";

/* flashrom programmers. */
static const char * const PROG_HOST = "host",
		  * const PROG_EC = "ec",
		  * const PROG_PD = "ec:dev=1";

static const char ROOTKEY_HASH_DEV[] =
		"b11d74edd286c144e1135b49e7f0bc20cf041f10";

enum wp_state {
	WP_DISABLED,
	WP_ENABLED,
};

enum target_type {
	TARGET_SELF,
	TARGET_UPDATE,
};

enum active_slot {
	SLOT_UNKNOWN = -1,
	SLOT_A = 0,
	SLOT_B,
};

enum flashrom_ops {
	FLASHROM_READ,
	FLASHROM_WRITE,
	FLASHROM_WP_STATUS,
};

enum rootkey_compat_result {
	ROOTKEY_COMPAT_OK,
	ROOTKEY_COMPAT_ERROR,
	ROOTKEY_COMPAT_REKEY,
	ROOTKEY_COMPAT_REKEY_TO_DEV,
};

/*
 * Helper function to create a new temporary file.
 * All files created will be removed by updater_remove_all_temp_files().
 * Returns the path of new file, or NULL on failure.
 */
const char *updater_create_temp_file(struct updater_config *cfg)
{
	struct tempfile *new_temp;
	char new_path[] = P_tmpdir "/fwupdater.XXXXXX";
	int fd;

	fd = mkstemp(new_path);
	if (fd < 0) {
		ERROR("Failed to create new temp file in %s\n", new_path);
		return NULL;
	}
	close(fd);
	new_temp = (struct tempfile *)malloc(sizeof(*new_temp));
	if (new_temp)
		new_temp->filepath = strdup(new_path);
	if (!new_temp || !new_temp->filepath) {
		remove(new_path);
		free(new_temp);
		ERROR("Failed to allocate buffer for new temp file.\n");
		return NULL;
	}
	VB2_DEBUG("Created new temporary file: %s.\n", new_path);
	new_temp->next = cfg->tempfiles;
	cfg->tempfiles = new_temp;
	return new_temp->filepath;
}

/*
 * Helper function to remove all files created by create_temp_file().
 * This is intended to be called only once at end of program execution.
 */
static void updater_remove_all_temp_files(struct updater_config *cfg)
{
	struct tempfile *tempfiles = cfg->tempfiles;
	while (tempfiles != NULL) {
		struct tempfile *target = tempfiles;
		VB2_DEBUG("Remove temporary file: %s.\n", target->filepath);
		remove(target->filepath);
		free(target->filepath);
		tempfiles = target->next;
		free(target);
	}
	cfg->tempfiles = NULL;
}

/*
 * Strip a string (usually from shell execution output) by removing all the
 * trailing characters in pattern. If pattern is NULL, match by space type
 * characters (space, new line, tab, ... etc).
 */
static void strip(char *s, const char *pattern)
{
	int len;
	assert(s);

	len = strlen(s);
	while (len-- > 0) {
		if (pattern) {
			if (!strchr(pattern, s[len]))
				break;
		} else {
			if (!isascii(s[len]) || !isspace(s[len]))
				break;
		}
		s[len] = '\0';
	}
}

/*
 * Executes a command on current host and returns stripped command output.
 * If the command has failed (exit code is not zero), returns an empty string.
 * The caller is responsible for releasing the returned string.
 */
char *host_shell(const char *command)
{
	/* Currently all commands we use do not have large output. */
	char buf[COMMAND_BUFFER_SIZE];

	int result;
	FILE *fp = popen(command, "r");

	VB2_DEBUG("%s\n", command);
	buf[0] = '\0';
	if (!fp) {
		VB2_DEBUG("Execution error for %s.\n", command);
		return strdup(buf);
	}

	if (fgets(buf, sizeof(buf), fp))
		strip(buf, NULL);
	result = pclose(fp);
	if (!WIFEXITED(result) || WEXITSTATUS(result) != 0) {
		VB2_DEBUG("Execution failure with exit code %d: %s\n",
			  WEXITSTATUS(result), command);
		/*
		 * Discard all output if command failed, for example command
		 * syntax failure may lead to garbage in stdout.
		 */
		buf[0] = '\0';
	}
	return strdup(buf);
}


/* An helper function to return "mainfw_act" system property.  */
static int host_get_mainfw_act(void)
{
	char buf[VB_MAX_STRING_PROPERTY];

	if (!VbGetSystemPropertyString("mainfw_act", buf, sizeof(buf)))
		return SLOT_UNKNOWN;

	if (strcmp(buf, FWACT_A) == 0)
		return SLOT_A;
	else if (strcmp(buf, FWACT_B) == 0)
		return SLOT_B;

	return SLOT_UNKNOWN;
}

/* A helper function to return the "tpm_fwver" system property. */
static int host_get_tpm_fwver(void)
{
	return VbGetSystemPropertyInt("tpm_fwver");
}

/* A helper function to return the "hardware write protection" status. */
static int host_get_wp_hw(void)
{
	/* wpsw refers to write protection 'switch', not 'software'. */
	int v = VbGetSystemPropertyInt("wpsw_cur");

	/* wpsw_cur may be not available, especially in recovery mode. */
	if (v < 0)
		v = VbGetSystemPropertyInt("wpsw_boot");

	return v;
}

/* A helper function to return "fw_vboot2" system property. */
static int host_get_fw_vboot2(void)
{
	return VbGetSystemPropertyInt("fw_vboot2");
}

/* A help function to get $(mosys platform version). */
static int host_get_platform_version(void)
{
	char *result = host_shell("mosys platform version");
	int rev = -1;

	/* Result should be 'revN' */
	if (strncmp(result, STR_REV, strlen(STR_REV)) == 0)
		rev = strtol(result + strlen(STR_REV), NULL, 0);
	VB2_DEBUG("Raw data = [%s], parsed version is %d\n", result, rev);

	free(result);
	return rev;
}

/*
 * A helper function to invoke flashrom(8) command.
 * Returns 0 if success, non-zero if error.
 */
static int host_flashrom(enum flashrom_ops op, const char *image_path,
			 const char *programmer, int verbose,
			 const char *section_name, const char *extra)
{
	char *command, *result;
	const char *op_cmd, *dash_i = "-i", *postfix = "";
	int r;

	switch (verbose) {
	case 0:
		postfix = " >/dev/null 2>&1";
		break;
	case 1:
		break;
	case 2:
		postfix = "-V";
		break;
	case 3:
		postfix = "-V -V";
		break;
	default:
		postfix = "-V -V -V";
		break;
	}

	if (!section_name || !*section_name) {
		dash_i = "";
		section_name = "";
	}

	switch (op) {
	case FLASHROM_READ:
		op_cmd = "-r";
		assert(image_path);
		break;

	case FLASHROM_WRITE:
		op_cmd = "-w";
		assert(image_path);
		break;

	case FLASHROM_WP_STATUS:
		op_cmd = "--wp-status";
		assert(image_path == NULL);
		image_path = "";
		/* grep is needed because host_shell only returns 1 line. */
		postfix = " 2>/dev/null | grep \"" \
			   FLASHROM_OUTPUT_WP_PATTERN "\"";
		break;

	default:
		assert(0);
		return -1;
	}

	if (!extra)
		extra = "";

	/* TODO(hungte) In future we should link with flashrom directly. */
	ASPRINTF(&command, "flashrom %s %s -p %s %s %s %s %s", op_cmd,
		 image_path, programmer, dash_i, section_name, extra,
		 postfix);

	if (verbose)
		INFO("Executing: %s\n", command);

	if (op != FLASHROM_WP_STATUS) {
		r = system(command);
		free(command);
		if (r)
			ERROR("Error code: %d\n", r);
		return r;
	}

	result = host_shell(command);
	strip(result, NULL);
	free(command);
	VB2_DEBUG("wp-status: %s\n", result);

	if (strstr(result, FLASHROM_OUTPUT_WP_ENABLED))
		r = WP_ENABLED;
	else if (strstr(result, FLASHROM_OUTPUT_WP_DISABLED))
		r = WP_DISABLED;
	else
		r = -1;
	free(result);
	return r;
}

/* Helper function to return write protection status via given programmer. */
static int host_get_wp(const char *programmer)
{
	return host_flashrom(FLASHROM_WP_STATUS, NULL, programmer, 0, NULL,
			     NULL);
}

/* Helper function to return host software write protection status. */
static int host_get_wp_sw(void)
{
	return host_get_wp(PROG_HOST);
}

/*
 * Gets the system property by given type.
 * If the property was not loaded yet, invoke the property getter function
 * and cache the result.
 * Returns the property value.
 */
int get_system_property(enum system_property_type property_type,
			struct updater_config *cfg)
{
	struct system_property *prop;

	assert(property_type < SYS_PROP_MAX);
	prop = &cfg->system_properties[property_type];
	if (!prop->initialized) {
		prop->initialized = 1;
		prop->value = prop->getter();
	}
	return prop->value;
}

static void print_system_properties(struct updater_config *cfg)
{
	int i;

	/*
	 * There may be error messages when fetching properties from active
	 * system, so we want to peek at them first and then print out.
	 */
	VB2_DEBUG("Scanning system properties...\n");
	for (i = 0; i < SYS_PROP_MAX; i++) {
		get_system_property((enum system_property_type)i, cfg);
	}

	printf("System properties: [");
	for (i = 0; i < SYS_PROP_MAX; i++) {
		printf("%d,",
		       get_system_property((enum system_property_type)i, cfg));
	}
	printf("]\n");
}

/*
 * Overrides the return value of a system property.
 * After invoked, next call to get_system_property(type, cfg) will return
 * the given value.
 */
static void override_system_property(enum system_property_type property_type,
				     struct updater_config *cfg,
				     int value)
{
	struct system_property *prop;

	assert(property_type < SYS_PROP_MAX);
	prop = &cfg->system_properties[property_type];
	prop->initialized = 1;
	prop->value = value;
}

/*
 * Overrides system properties from a given list.
 * The list should be string of integers eliminated by comma and/or space.
 * For example, "1 2 3" and "1,2,3" both overrides first 3 properties.
 * To skip some properties you have to use comma, for example
 * "1, , 3" will only override the first and 3rd properties.
 * Invalid characters and fields will be ignored.
 *
 * The current implementation is only for unit testing.
 * In future we may extend this with name=value so users can use it easily on
 * actual systems.
 */
static void override_properties_from_list(const char *override_list,
					  struct updater_config *cfg)
{
	const char *s = override_list;
	char *e, c;
	int i = 0, wait_comma = 0;
	long int v;

	VB2_DEBUG("Input is <%s>\n", override_list);
	for (c = *s; c; c = *++s) {
		if (c == ',') {
			if (!wait_comma)
				i++;
			wait_comma = 0;
		}
		if (!isascii(c) || !(isdigit(c) || c == '-'))
			continue;
		if (i >= SYS_PROP_MAX) {
			ERROR("Too many fields (max is %d): %s.\n",
			      SYS_PROP_MAX, override_list);
			return;
		}
		v = strtol(s, &e, 0);
		s = e - 1;
		VB2_DEBUG("property[%d].value = %ld\n", i, v);
		override_system_property((enum system_property_type)i, cfg, v);
		wait_comma = 1;
		i++;
	}
}

/* Gets the value (setting) of specified quirks from updater configuration. */
int get_config_quirk(enum quirk_types quirk, const struct updater_config *cfg)
{
	assert(quirk < QUIRK_MAX);
	return cfg->quirks[quirk].value;
}

/* Prints the name and description from all supported quirks. */
void updater_list_config_quirks(const struct updater_config *cfg)
{
	const struct quirk_entry *entry = cfg->quirks;
	int i;

	printf("Supported quirks:\n");
	for (i = 0; i < QUIRK_MAX; i++, entry++) {
		printf(" '%s': %s (default: %d)\n", entry->name,
		       entry->help ? entry->help : "(no description)",
		       get_config_quirk((enum quirk_types)i, cfg));
	}
}

/*
 * Applies a quirk if applicable (the value should be non-zero).
 * Returns 0 on success, otherwise failure.
 */
static int try_apply_quirk(enum quirk_types quirk, struct updater_config *cfg)
{
	const struct quirk_entry *entry = cfg->quirks + quirk;
	assert(quirk < QUIRK_MAX);

	if (!entry->value)
		return 0;

	if (!entry->apply) {
		ERROR("<%s> not implemented.\n", entry->name);
		return -1;
	}
	VB2_DEBUG("Applying quirk <%s>.\n", entry->name);
	return entry->apply(cfg);
}

/*
 * Initialize the updater_config quirks from a list of settings.
 * Returns 0 on success, otherwise failure.
 */
static int setup_config_quirks(const char *quirks, struct updater_config *cfg)
{
	/*
	 * The list should be in NAME[=VALUE],...
	 * Value defaults to 1 if not specified.
	 */
	int r = 0;
	char *buf = strdup(quirks);
	char *token;

	token = strtok(buf, ", ");
	for (; token; token = strtok(NULL, ", ")) {
		const char *name = token;
		char *equ = strchr(token, '=');
		int i, value = 1;
		struct quirk_entry *entry = cfg->quirks;

		if (equ) {
			*equ = '\0';
			value = strtol(equ + 1, NULL, 0);
		}

		VB2_DEBUG("Looking for quirk <%s=%d>.\n", name, value);
		for (i = 0; i < QUIRK_MAX; i++, entry++) {
			if (strcmp(name, entry->name))
				continue;
			entry->value = value;
			VB2_DEBUG("Set quirk %s to %d.\n", entry->name, value);
			break;
		}
		if (i >= QUIRK_MAX) {
			ERROR("Unknown quirk: %s\n", name);
			r++;
		}
	}
	free(buf);
	return r;
}

/*
 * Finds a firmware section by given name in the firmware image.
 * If successful, return zero and *section argument contains the address and
 * size of the section; otherwise failure.
 */
int find_firmware_section(struct firmware_section *section,
			  const struct firmware_image *image,
			  const char *section_name)
{
	FmapAreaHeader *fah = NULL;
	uint8_t *ptr;

	section->data = NULL;
	section->size = 0;
	ptr = fmap_find_by_name(
			image->data, image->size, image->fmap_header,
			section_name, &fah);
	if (!ptr)
		return -1;
	section->data = (uint8_t *)ptr;
	section->size = fah->area_size;
	return 0;
}

/*
 * Returns true if the given FMAP section exists in the firmware image.
 */
static int firmware_section_exists(const struct firmware_image *image,
				   const char *section_name)
{
	struct firmware_section section;
	find_firmware_section(&section, image, section_name);
	return section.data != NULL;
}

/*
 * Checks if the section is filled with given character.
 * If section size is 0, return 0. If section is not empty, return non-zero if
 * the section is filled with same character c, otherwise 0.
 */
static int section_is_filled_with(const struct firmware_section *section,
				  uint8_t c)
{
	uint32_t i;
	if (!section->size)
		return 0;
	for (i = 0; i < section->size; i++)
		if (section->data[i] != c)
			return 0;
	return 1;
}

/*
 * Loads the firmware information from an FMAP section in loaded firmware image.
 * The section should only contain ASCIIZ string as firmware version.
 * If successful, the return value is zero and *version points to a newly
 * allocated string as firmware version (caller must free it); otherwise
 * failure.
 */
static int load_firmware_version(struct firmware_image *image,
				 const char *section_name,
				 char **version)
{
	struct firmware_section fwid;
	find_firmware_section(&fwid, image, section_name);
	if (fwid.size) {
		*version = strndup((const char*)fwid.data, fwid.size);
		/*
		 * For 'system current' images, the version string may contain
		 * invalid characters that we do want to strip.
		 */
		strip(*version, "\xff");
		return 0;
	}
	*version = strdup("");
	return -1;
}

/*
 * Loads a firmware image from file.
 * If archive is provided and file_name is a relative path, read the file from
 * archive.
 * Returns 0 on success, otherwise failure.
 */
int load_firmware_image(struct firmware_image *image, const char *file_name,
			struct archive *archive)
{
	VB2_DEBUG("Load image file from %s...\n", file_name);

	if (!archive_has_entry(archive, file_name)) {
		ERROR("Does not exist: %s\n", file_name);
		return -1;
	}
	if (archive_read_file(archive, file_name, &image->data, &image->size) !=
	    VB2_SUCCESS) {
		ERROR("Failed to load %s\n", file_name);
		return -1;
	}

	VB2_DEBUG("Image size: %d\n", image->size);
	assert(image->data);
	image->file_name = strdup(file_name);

	image->fmap_header = fmap_find(image->data, image->size);
	if (!image->fmap_header) {
		ERROR("Invalid image file (missing FMAP): %s\n", file_name);
		return -1;
	}

	if (!firmware_section_exists(image, FMAP_RO_FRID)) {
		ERROR("Does not look like VBoot firmware image: %s\n",
		      file_name);
		return -1;
	}

	load_firmware_version(image, FMAP_RO_FRID, &image->ro_version);
	if (firmware_section_exists(image, FMAP_RW_FWID_A)) {
		char **a = &image->rw_version_a, **b = &image->rw_version_b;
		load_firmware_version(image, FMAP_RW_FWID_A, a);
		load_firmware_version(image, FMAP_RW_FWID_B, b);
	} else if (firmware_section_exists(image, FMAP_RW_FWID)) {
		char **a = &image->rw_version_a, **b = &image->rw_version_b;
		load_firmware_version(image, FMAP_RW_FWID, a);
		load_firmware_version(image, FMAP_RW_FWID, b);
	} else {
		ERROR("Unsupported VBoot firmware (no RW ID): %s\n", file_name);
	}
	return 0;
}

/*
 * Loads the active system firmware image (usually from SPI flash chip).
 * Returns 0 if success, non-zero if error.
 */
int load_system_firmware(struct updater_config *cfg,
			 struct firmware_image *image)
{
	const char *tmp_file = updater_create_temp_file(cfg);

	if (!tmp_file)
		return -1;
	RETURN_ON_FAILURE(host_flashrom(
			FLASHROM_READ, tmp_file, image->programmer,
			cfg->verbosity, NULL, NULL));
	return load_firmware_image(image, tmp_file, NULL);
}

/*
 * Frees the allocated resource from a firmware image object.
 */
void free_firmware_image(struct firmware_image *image)
{
	/*
	 * The programmer is not allocated by load_firmware_image and must be
	 * preserved explicitly.
	 */
	const char *programmer = image->programmer;

	free(image->data);
	free(image->file_name);
	free(image->ro_version);
	free(image->rw_version_a);
	free(image->rw_version_b);
	memset(image, 0, sizeof(*image));
	image->programmer = programmer;
}

/*
 * Decides which target in RW firmware to manipulate.
 * The `target` argument specifies if we want to know "the section to be
 * update" (TARGET_UPDATE), or "the (active) section * to check" (TARGET_SELF).
 * Returns the section name if success, otherwise NULL.
 */
static const char *decide_rw_target(struct updater_config *cfg,
				    enum target_type target,
				    int is_vboot2)
{
	const char *a = FMAP_RW_SECTION_A, *b = FMAP_RW_SECTION_B;
	int slot = get_system_property(SYS_PROP_MAINFW_ACT, cfg);

	/* In vboot1, always update B and check content with A. */
	if (!is_vboot2)
		return target == TARGET_UPDATE ? b : a;

	switch (slot) {
	case SLOT_A:
		return target == TARGET_UPDATE ? b : a;

	case SLOT_B:
		return target == TARGET_UPDATE ? a : b;
	}

	return NULL;
}

/*
 * Sets any needed system properties to indicate system should try the new
 * firmware on next boot.
 * The `target` argument is an FMAP section name indicating which to try.
 * Returns 0 if success, non-zero if error.
 */
static int set_try_cookies(struct updater_config *cfg, const char *target,
			   int is_vboot2)
{
	int tries = 6;
	const char *slot;

	/* EC Software Sync needs few more reboots. */
	if (cfg->ec_image.data)
		tries += 2;

	/* Find new slot according to target (section) name. */
	if (strcmp(target, FMAP_RW_SECTION_A) == 0)
		slot = FWACT_A;
	else if (strcmp(target, FMAP_RW_SECTION_B) == 0)
		slot = FWACT_B;
	else {
		ERROR("Unknown target: %s\n", target);
		return -1;
	}

	if (cfg->emulation) {
		INFO("(emulation) Setting try_next to %s, try_count to %d.\n",
		     slot, tries);
		return 0;
	}

	if (is_vboot2 && VbSetSystemPropertyString("fw_try_next", slot)) {
		ERROR("Failed to set fw_try_next to %s.\n", slot);
		return -1;
	}
	if (VbSetSystemPropertyInt("fw_try_count", tries)) {
		ERROR("Failed to set fw_try_count to %d.\n", tries);
		return -1;
	}
	return 0;
}

/*
 * Emulates writing to firmware.
 * Returns 0 if success, non-zero if error.
 */
static int emulate_write_firmware(const char *filename,
				  const struct firmware_image *image,
				  const char *section_name)
{
	struct firmware_image to_image = {0};
	struct firmware_section from, to;
	int errorcnt = 0;

	from.data = image->data;
	from.size = image->size;

	if (load_firmware_image(&to_image, filename, NULL)) {
		ERROR("Cannot load image from %s.\n", filename);
		return -1;
	}

	if (section_name) {
		find_firmware_section(&from, image, section_name);
		if (!from.data) {
			ERROR("No section %s in source image %s.\n",
			      section_name, image->file_name);
			errorcnt++;
		}
		find_firmware_section(&to, &to_image, section_name);
		if (!to.data) {
			ERROR("No section %s in destination image %s.\n",
			      section_name, filename);
			errorcnt++;
		}
	} else if (image->size != to_image.size) {
		ERROR("Image size is different (%s:%d != %s:%d)\n",
		      image->file_name, image->size, to_image.file_name,
		      to_image.size);
		errorcnt++;
	} else {
		to.data = to_image.data;
		to.size = to_image.size;
	}

	if (!errorcnt) {
		size_t to_write = VB2_MIN(to.size, from.size);

		assert(from.data && to.data);
		VB2_DEBUG("Writing %zu bytes\n", to_write);
		memcpy(to.data, from.data, to_write);
	}

	if (!errorcnt && vb2_write_file(
			filename, to_image.data, to_image.size)) {
		ERROR("Failed writing to file: %s\n", filename);
		errorcnt++;
	}

	free_firmware_image(&to_image);
	return errorcnt;
}

/*
 * Writes a section from given firmware image to system firmware.
 * If section_name is NULL, write whole image.
 * Returns 0 if success, non-zero if error.
 */
static int write_firmware(struct updater_config *cfg,
			  const struct firmware_image *image,
			  const char *section_name)
{
	const char *tmp_file = updater_create_temp_file(cfg);
	const char *tmp_diff_file = NULL;
	const char *programmer = image->programmer;
	char *extra = NULL;
	int r;

	if (!tmp_file)
		return -1;

	if (cfg->emulation) {
		INFO("(emulation) Writing %s from %s to %s (emu=%s).\n",
		     section_name ? section_name : "whole image",
		     image->file_name, programmer, cfg->emulation);

		return emulate_write_firmware(
				cfg->emulation, image, section_name);

	}
	if (vb2_write_file(tmp_file, image->data, image->size) != VB2_SUCCESS) {
		ERROR("Cannot write temporary file for output: %s\n", tmp_file);
		return -1;
	}
	if (cfg->fast_update && image == &cfg->image && cfg->image_current.data)
	{
		tmp_diff_file = updater_create_temp_file(cfg);
		if (vb2_write_file(tmp_diff_file, cfg->image_current.data,
				   cfg->image_current.size) != VB2_SUCCESS) {
			ERROR("Cannot write temporary file for diff image\n");
			return -1;
		}
		ASPRINTF(&extra, "--noverify --diff=%s", tmp_diff_file);
	}
	r = host_flashrom(FLASHROM_WRITE, tmp_file, programmer,
			  cfg->verbosity + 1, section_name, extra);
	free(extra);
	return r;
}

/*
 * Write a section from given firmware image to system firmware if possible.
 * If section_name is NULL, write whole image.  If the image has no data or if
 * the section does not exist, ignore and return success.
 * Returns 0 if success, non-zero if error.
 */
static int write_optional_firmware(struct updater_config *cfg,
				   const struct firmware_image *image,
				   const char *section_name,
				   int check_programmer_wp,
				   int is_host)
{
	if (!image->data) {
		VB2_DEBUG("No data in <%s> image.\n", image->programmer);
		return 0;
	}
	if (section_name && !firmware_section_exists(image, section_name)) {
		VB2_DEBUG("Image %s<%s> does not have section %s.\n",
			  image->file_name, image->programmer, section_name);
		return 0;
	}
	/* Currently only host emulation is supported. */
	if (cfg->emulation && !is_host) {
		INFO("(emulation) Update %s from %s to %s (%d bytes), "
		     "skipped for non-host targets in emulation.\n",
		     section_name ? section_name : "whole image",
		     image->file_name, image->programmer, image->size);
		return 0;
	}

	/*
	 * EC & PD may have different WP settings and we want to write
	 * only if it is OK.
	 */
	if (check_programmer_wp &&
	    get_system_property(SYS_PROP_WP_HW, cfg) == WP_ENABLED &&
	    host_get_wp(image->programmer) == WP_ENABLED) {
		ERROR("Target %s is write protected, skip updating.\n",
		      image->programmer);
		return 0;
	}

	return write_firmware(cfg, image, section_name);
}

/*
 * Preserves (copies) the given section (by name) from image_from to image_to.
 * The offset may be different, and the section data will be directly copied.
 * If the section does not exist on either images, return as failure.
 * If the source section is larger, contents on destination be truncated.
 * If the source section is smaller, the remaining area is not modified.
 * Returns 0 if success, non-zero if error.
 */
int preserve_firmware_section(const struct firmware_image *image_from,
			      struct firmware_image *image_to,
			      const char *section_name)
{
	struct firmware_section from, to;

	find_firmware_section(&from, image_from, section_name);
	find_firmware_section(&to, image_to, section_name);
	if (!from.data || !to.data) {
		VB2_DEBUG("Cannot find section %.*s: from=%p, to=%p\n",
			  FMAP_NAMELEN, section_name, from.data, to.data);
		return -1;
	}
	if (from.size > to.size) {
		WARN("Section %.*s is truncated after updated.\n",
		     FMAP_NAMELEN, section_name);
	}
	/* Use memmove in case if we need to deal with sections that overlap. */
	memmove(to.data, from.data, VB2_MIN(from.size, to.size));
	return 0;
}

/*
 * Finds the GBB (Google Binary Block) header on a given firmware image.
 * Returns a pointer to valid GBB header, or NULL on not found.
 */
const struct vb2_gbb_header *find_gbb(const struct firmware_image *image)
{
	struct firmware_section section;
	struct vb2_gbb_header *gbb_header;

	find_firmware_section(&section, image, FMAP_RO_GBB);
	gbb_header = (struct vb2_gbb_header *)section.data;
	if (!futil_valid_gbb_header(gbb_header, section.size, NULL)) {
		ERROR("Cannot find GBB in image: %s.\n", image->file_name);
		return NULL;
	}
	return gbb_header;
}

/*
 * Preserve the GBB contents from image_from to image_to.
 * HWID is always preserved, and flags are preserved only if preserve_flags set.
 * Returns 0 if success, otherwise -1 if GBB header can't be found or if HWID is
 * too large.
 */
static int preserve_gbb(const struct firmware_image *image_from,
			struct firmware_image *image_to,
			int preserve_flags)
{
	const struct vb2_gbb_header *gbb_from;
	struct vb2_gbb_header *gbb_to;

	gbb_from = find_gbb(image_from);
	/* We do want to change GBB contents later. */
	gbb_to = (struct vb2_gbb_header *)find_gbb(image_to);

	if (!gbb_from || !gbb_to)
		return -1;

	/* Preserve flags (for non-factory mode). */
	if (preserve_flags)
		gbb_to->flags = gbb_from->flags;

	/* Preserve HWID. */
	return futil_set_gbb_hwid(
			gbb_to, (const char *)gbb_from + gbb_from->hwid_offset);
}

/*
 * Preserves the regions locked by Intel management engine.
 */
static int preserve_management_engine(struct updater_config *cfg,
				      const struct firmware_image *image_from,
				      struct firmware_image *image_to)
{
	struct firmware_section section;

	find_firmware_section(&section, image_from, FMAP_SI_ME);
	if (!section.data) {
		VB2_DEBUG("Skipped because no section %s.\n", FMAP_SI_ME);
		return 0;
	}
	if (section_is_filled_with(&section, 0xFF)) {
		VB2_DEBUG("ME is probably locked - preserving %s.\n",
			  FMAP_SI_DESC);
		return preserve_firmware_section(
				image_from, image_to, FMAP_SI_DESC);
	}

	return try_apply_quirk(QUIRK_UNLOCK_ME_FOR_UPDATE, cfg);
}

/* Preserve firmware sections by FMAP area flags. */
static int preserve_fmap_sections(struct firmware_image *from,
				  struct firmware_image *to,
				  int *count)
{
	int i, errcnt = 0;
	FmapHeader *fmap = to->fmap_header;
	FmapAreaHeader *ah = (FmapAreaHeader*)(
			(uint8_t *)fmap + sizeof(FmapHeader));
	*count = 0;

	for (i = 0; i < fmap->fmap_nareas; i++, ah++) {
		if (!(ah->area_flags & FMAP_AREA_PRESERVE))
			continue;
		/* Warning: area_name 'may' not end with NUL. */
		if (!firmware_section_exists(from, ah->area_name)) {
			VB2_DEBUG("FMAP area does not exist in source: %.*s\n",
				  FMAP_NAMELEN, ah->area_name);
			continue;
		}
		VB2_DEBUG("Preserve FMAP area: %.*s\n", FMAP_NAMELEN,
			  ah->area_name);
		errcnt += preserve_firmware_section(from, to, ah->area_name);
		(*count)++;
	}

	return errcnt;
}

/*
 * Preserve old images without "preserve" information in FMAP.
 * We have to use the legacy hard-coded list of names.
 */
static int preserve_known_sections(struct firmware_image *from,
				   struct firmware_image *to)
{
	int errcnt = 0, i;
	const char * const names[] = {
		"RO_PRESERVE",
		"RW_PRESERVE",
		"RO_VPD",
		"RW_VPD",
		"SMMSTORE",
		"RW_NVRAM",
		"RW_ELOG",
		/*
		 * TODO(hungte): b/116326638: Remove RO_FSG after the migration
		 * is finished.
		 */
		"RO_FSG",
		 /*
		  * TODO(hungte): crbug.com/936768: Remove SI_GBE, SI_PDR after
		  * both migrated to the new FMAP based preserve method.
		  */
		"SI_GBE",
		"SI_PDR",
	};

	for (i = 0; i < ARRAY_SIZE(names); i++) {
		if (!firmware_section_exists(from, names[i]))
			continue;
		VB2_DEBUG("Preserve firmware section: %s\n", names[i]);
		errcnt += preserve_firmware_section(from, to, names[i]);
	}
	return errcnt;
}

/*
 * Preserves the critical sections from the current (active) firmware.
 * Currently preserved sections: GBB (HWID and flags), x86 ME, and any firmware
 * sections with FMAP_AREA_PRESERVE flag set (or a list of known names).
 * Returns 0 if success, non-zero if error.
 */
static int preserve_images(struct updater_config *cfg)
{
	int errcnt = 0, found;
	struct firmware_image *from = &cfg->image_current, *to = &cfg->image;

	errcnt += preserve_gbb(from, to, !cfg->factory_update);
	errcnt += preserve_management_engine(cfg, from, to);
	errcnt += preserve_fmap_sections(from, to, &found);

	if (!found)
		errcnt += preserve_known_sections(from, to);

	return errcnt;
}

/*
 * Compares if two sections have same size and data.
 * Returns 0 if given sections are the same, otherwise non-zero.
 */
static int compare_section(const struct firmware_section *a,
			   const struct firmware_section *b)
{
	if (a->size != b->size)
		return a->size - b->size;
	return memcmp(a->data, b->data, a->size);
}

/*
 * Returns if the images are different (should be updated) in given section.
 * If the section contents are the same or if the section does not exist on both
 * images, return value is 0 (no need to update). Otherwise the return value is
 * non-zero, indicating an update should be performed.
 * If section_name is NULL, compare whole images.
 */
static int section_needs_update(const struct firmware_image *image_from,
				const struct firmware_image *image_to,
				const char *section_name)
{
	struct firmware_section from, to;

	if (!section_name) {
		if (image_from->size != image_to->size)
			return -1;
		return memcmp(image_from->data, image_to->data, image_to->size);
	}

	find_firmware_section(&from, image_from, section_name);
	find_firmware_section(&to, image_to, section_name);

	return compare_section(&from, &to);
}

/*
 * Returns true if the write protection is enabled on current system.
 */
static int is_write_protection_enabled(struct updater_config *cfg)
{
	/* Default to enabled. */
	int wp = get_system_property(SYS_PROP_WP_HW, cfg);
	if (wp == WP_DISABLED)
		return wp;
	/* For error or enabled, check WP SW. */
	wp = get_system_property(SYS_PROP_WP_SW, cfg);
	/* Consider all errors as enabled. */
	if (wp != WP_DISABLED)
		return WP_ENABLED;
	return wp;
}

/*
 * Checks if the given firmware images are compatible with current platform.
 * In current implementation (following Chrome OS style), we assume the platform
 * is identical to the name before a dot (.) in firmware version.
 * Returns 0 for success, otherwise failure.
 */
static int check_compatible_platform(struct updater_config *cfg)
{
	int len;
	struct firmware_image *image_from = &cfg->image_current,
			      *image_to = &cfg->image;
	const char *from_dot = strchr(image_from->ro_version, '.'),
	           *to_dot = strchr(image_to->ro_version, '.');

	if (!from_dot || !to_dot) {
		VB2_DEBUG("Missing dot (from=%p, to=%p)\n", from_dot, to_dot);
		return -1;
	}
	len = from_dot - image_from->ro_version + 1;
	VB2_DEBUG("Platform: %*.*s\n", len, len, image_from->ro_version);
	return strncmp(image_from->ro_version, image_to->ro_version, len);
}

/*
 * Returns a valid root key from GBB header, or NULL on failure.
 */
static const struct vb2_packed_key *get_rootkey(
		const struct vb2_gbb_header *gbb)
{
	struct vb2_packed_key *key = NULL;

	key = (struct vb2_packed_key *)((uint8_t *)gbb + gbb->rootkey_offset);
	if (!packed_key_looks_ok(key, gbb->rootkey_size)) {
		ERROR("Invalid root key.\n");
		return NULL;
	}
	return key;
}

/*
 * Returns a key block key from given image section, or NULL on failure.
 */
static const struct vb2_keyblock *get_keyblock(
		const struct firmware_image *image,
		const char *section_name)
{
	struct firmware_section section;

	find_firmware_section(&section, image, section_name);
	/* A keyblock must be followed by a vb2_fw_preamble. */
	if (section.size < sizeof(struct vb2_keyblock) +
	    sizeof(struct vb2_fw_preamble)) {
		ERROR("Invalid section: %s\n", section_name);
		return NULL;
	}
	return (const struct vb2_keyblock *)section.data;
}

/*
 * Duplicates a key block and returns the duplicated block.
 * The caller must free the returned key block after being used.
 */
static struct vb2_keyblock *dupe_keyblock(const struct vb2_keyblock *block)
{
	struct vb2_keyblock *new_block;

	new_block = (struct vb2_keyblock *)malloc(block->keyblock_size);
	assert(new_block);
	memcpy(new_block, block, block->keyblock_size);
	return new_block;
}

/*
 * Verifies if keyblock is signed with given key.
 * Returns 0 on success, otherwise failure.
 */
static int verify_keyblock(const struct vb2_keyblock *block,
			   const struct vb2_packed_key *sign_key) {
	int r;
	uint8_t workbuf[VB2_FIRMWARE_WORKBUF_RECOMMENDED_SIZE];
	struct vb2_workbuf wb;
	struct vb2_public_key key;
	struct vb2_keyblock *new_block;

	if (block->keyblock_signature.sig_size == 0) {
		ERROR("Keyblock is not signed.\n");
		return -1;
	}
	vb2_workbuf_init(&wb, workbuf, sizeof(workbuf));
	if (VB2_SUCCESS != vb2_unpack_key(&key, sign_key)) {
		ERROR("Invalid signing key.\n");
		return -1;
	}

	/*
	 * vb2_verify_keyblock will destroy the signature inside keyblock
	 * so we have to verify with a local copy.
	 */
	new_block = dupe_keyblock(block);
	r = vb2_verify_keyblock(new_block, new_block->keyblock_size, &key, &wb);
	free(new_block);

	if (r != VB2_SUCCESS) {
		ERROR("Failed verifying key block.\n");
		return -1;
	}
	return 0;
}

/*
 * Gets the data key and firmware version from a section on firmware image.
 * The section should contain a vb2_keyblock and a vb2_fw_preamble immediately
 * after key block so we can decode and save the data key and firmware version
 * into argument `data_key_version` and `firmware_version`.
 * Returns 0 for success, otherwise failure.
 */
static int get_key_versions(const struct firmware_image *image,
			    const char *section_name,
			    unsigned int *data_key_version,
			    unsigned int *firmware_version)
{
	const struct vb2_keyblock *keyblock = get_keyblock(image, section_name);
	const struct vb2_fw_preamble *pre;

	if (!keyblock)
		return -1;
	*data_key_version = keyblock->data_key.key_version;
	pre = (struct vb2_fw_preamble *)((uint8_t*)keyblock +
					 keyblock->keyblock_size);
	*firmware_version = pre->firmware_version;
	VB2_DEBUG("%s: data key version = %d, firmware version = %d\n",
		  image->file_name, *data_key_version, *firmware_version);
	return 0;
}

/*
 * Checks if the root key in ro_image can verify vblocks in rw_image.
 * Returns 0 for success, otherwise failure.
 */
static enum rootkey_compat_result check_compatible_root_key(
		const struct firmware_image *ro_image,
		const struct firmware_image *rw_image)
{
	const struct vb2_gbb_header *gbb = find_gbb(ro_image);
	const struct vb2_packed_key *rootkey;
	const struct vb2_keyblock *keyblock;

	if (!gbb)
		return ROOTKEY_COMPAT_ERROR;

	rootkey = get_rootkey(gbb);
	if (!rootkey)
		return ROOTKEY_COMPAT_ERROR;

	/* Assume VBLOCK_A and VBLOCK_B are signed in same way. */
	keyblock = get_keyblock(rw_image, FMAP_RW_VBLOCK_A);
	if (!keyblock)
		return ROOTKEY_COMPAT_ERROR;

	if (verify_keyblock(keyblock, rootkey) != 0) {
		const struct vb2_gbb_header *gbb_rw = find_gbb(rw_image);
		const struct vb2_packed_key *rootkey_rw = NULL;
		int is_same_key = 0, to_dev = 0;
		/*
		 * Try harder to provide more info.
		 * packed_key_sha1_string uses static buffer so don't call
		 * it twice in args list of one expression.
		 */
		if (gbb_rw)
			rootkey_rw = get_rootkey(gbb_rw);
		if (rootkey_rw) {
			if (rootkey->key_offset == rootkey_rw->key_offset &&
			    rootkey->key_size == rootkey_rw->key_size &&
			    memcmp(rootkey, rootkey_rw, rootkey->key_size +
				   rootkey->key_offset) == 0)
				is_same_key = 1;
			if (strcmp(packed_key_sha1_string(rootkey_rw),
				   ROOTKEY_HASH_DEV) == 0)
				to_dev = 1;
		}
		INFO("Current (RO) firmware image has root key: %s\n",
		     packed_key_sha1_string(rootkey));
		if (is_same_key) {
			ERROR("Rootkey is same as target (RW) image. \n"
			      "Maybe RW corrupted?");
			return ROOTKEY_COMPAT_ERROR;
		}
		WARN("Target (RW) image is signed by root key: %s%s\n",
		     rootkey_rw ? packed_key_sha1_string(rootkey_rw) :
		     "<invalid>", to_dev ? " (DEV/unsigned)" : "");
		return to_dev ? ROOTKEY_COMPAT_REKEY_TO_DEV :
				ROOTKEY_COMPAT_REKEY;
	}
	return ROOTKEY_COMPAT_OK;
}

/*
 * Returns 1 if a given file (cbfs_entry_name) exists inside a particular CBFS
 * section of an image file, otherwise 0.
 */
static int cbfs_file_exists(const char *image_file,
			    const char *section_name,
			    const char *cbfs_entry_name)
{
	char *cmd;
	int r;

	ASPRINTF(&cmd,
		 "cbfstool '%s' print -r %s 2>/dev/null | grep -q '^%s '",
		 image_file, section_name, cbfs_entry_name);
	r = system(cmd);
	free(cmd);
	return !r;
}

/*
 * Returns non-zero if the RW_LEGACY needs to be updated, otherwise 0.
 */
static int legacy_needs_update(struct updater_config *cfg)
{
	int has_from, has_to;
	const char * const tag = "cros_allow_auto_update";
	const char *section = FMAP_RW_LEGACY;
	const char *tmp_path = updater_create_temp_file(cfg);

	VB2_DEBUG("Checking %s contents...\n", FMAP_RW_LEGACY);
	if (!tmp_path ||
	    vb2_write_file(tmp_path, cfg->image.data, cfg->image.size)) {
		ERROR("Failed to create temporary file for image contents.\n");
		return 0;
	}

	has_to = cbfs_file_exists(tmp_path, section, tag);
	has_from = cbfs_file_exists(tmp_path, section, tag);

	if (!has_from || !has_to) {
		VB2_DEBUG("Current legacy firmware has%s updater tag (%s) and "
			  "target firmware has%s updater tag, won't update.\n",
			  has_from ? "" : " no", tag, has_to ? "" : " no");
		return 0;
	}

	return section_needs_update(
			&cfg->image_current, &cfg->image, FMAP_RW_LEGACY);
}

/*
 * Checks if the given firmware image is signed with a key that won't be
 * blocked by TPM's anti-rollback detection.
 * Returns 0 for success, otherwise failure.
 */
static int do_check_compatible_tpm_keys(struct updater_config *cfg,
					const struct firmware_image *rw_image)
{
	unsigned int data_key_version = 0, firmware_version = 0,
		     tpm_data_key_version = 0, tpm_firmware_version = 0;
	int tpm_fwver = 0;

	/* Fail if the given image does not look good. */
	if (get_key_versions(rw_image, FMAP_RW_VBLOCK_A, &data_key_version,
			     &firmware_version) != 0)
		return -1;

	/* The stored tpm_fwver can be 0 (b/116298359#comment3). */
	tpm_fwver = get_system_property(SYS_PROP_TPM_FWVER, cfg);
	if (tpm_fwver < 0) {
		ERROR("Invalid tpm_fwver: %d.\n", tpm_fwver);
		return -1;
	}

	tpm_data_key_version = tpm_fwver >> 16;
	tpm_firmware_version = tpm_fwver & 0xffff;
	VB2_DEBUG("TPM: data_key_version = %d, firmware_version = %d\n",
		  tpm_data_key_version, tpm_firmware_version);

	if (tpm_data_key_version > data_key_version) {
		ERROR("Data key version rollback detected (%d->%d).\n",
		      tpm_data_key_version, data_key_version);
		return -1;
	}
	if (tpm_firmware_version > firmware_version) {
		ERROR("Firmware version rollback detected (%d->%d).\n",
		      tpm_firmware_version, firmware_version);
		return -1;
	}
	return 0;
}

/*
 * Wrapper for do_check_compatible_tpm_keys.
 * Will return 0 if do_check_compatible_tpm_keys success or if cfg.force_update
 * is set; otherwise non-zero.
 */
static int check_compatible_tpm_keys(struct updater_config *cfg,
				     const struct firmware_image *rw_image)
{
	int r = do_check_compatible_tpm_keys(cfg, rw_image);
	if (!r)
		return r;
	if (!cfg->force_update) {
		ERROR("Add --force if you want to waive TPM checks.\n");
		return r;
	}
	WARN("TPM KEYS CHECK IS WAIVED BY --force. YOU ARE ON YOUR OWN.\n");
	return 0;
}

const char * const updater_error_messages[] = {
	[UPDATE_ERR_DONE] = "Done (no error)",
	[UPDATE_ERR_NEED_RO_UPDATE] = "RO changed and no WP. Need full update.",
	[UPDATE_ERR_NO_IMAGE] = "No image to update; try specify with -i.",
	[UPDATE_ERR_SYSTEM_IMAGE] = "Cannot load system active firmware.",
	[UPDATE_ERR_INVALID_IMAGE] = "The given firmware image is not valid.",
	[UPDATE_ERR_SET_COOKIES] = "Failed writing system flags to try update.",
	[UPDATE_ERR_WRITE_FIRMWARE] = "Failed writing firmware.",
	[UPDATE_ERR_PLATFORM] = "Your system platform is not compatible.",
	[UPDATE_ERR_TARGET] = "No valid RW target to update. Abort.",
	[UPDATE_ERR_ROOT_KEY] = "RW signed by incompatible root key "
			        "(different from RO).",
	[UPDATE_ERR_TPM_ROLLBACK] = "RW not usable due to TPM anti-rollback.",
	[UPDATE_ERR_UNKNOWN] = "Unknown error.",
};

/*
 * The main updater for "Try-RW update", to update only one RW section
 * and try if it can boot properly on reboot.
 * This was also known as --mode=autoupdate,--wp=1 in legacy updater.
 * Returns UPDATE_ERR_DONE if success, otherwise error.
 */
static enum updater_error_codes update_try_rw_firmware(
		struct updater_config *cfg,
		struct firmware_image *image_from,
		struct firmware_image *image_to,
		int wp_enabled)
{
	const char *target;
	int has_update = 1;
	int is_vboot2 = get_system_property(SYS_PROP_FW_VBOOT2, cfg);

	preserve_gbb(image_from, image_to, 1);
	if (!wp_enabled && section_needs_update(
			image_from, image_to, FMAP_RO_SECTION))
		return UPDATE_ERR_NEED_RO_UPDATE;

	INFO("Checking compatibility...\n");
	if (check_compatible_root_key(image_from, image_to))
		return UPDATE_ERR_ROOT_KEY;
	if (check_compatible_tpm_keys(cfg, image_to))
		return UPDATE_ERR_TPM_ROLLBACK;

	VB2_DEBUG("Firmware %s vboot2.\n", is_vboot2 ?  "is" : "is NOT");
	target = decide_rw_target(cfg, TARGET_SELF, is_vboot2);
	if (target == NULL) {
		ERROR("TRY-RW update needs system to boot in RW firmware.\n");
		return UPDATE_ERR_TARGET;
	}

	INFO("Checking %s contents...\n", target);
	if (!firmware_section_exists(image_to, target)) {
		ERROR("Cannot find section '%s' on firmware image: %s\n",
		      target, image_to->file_name);
		return UPDATE_ERR_INVALID_IMAGE;
	}
	if (!cfg->force_update)
		has_update = section_needs_update(image_from, image_to, target);

	if (has_update) {
		target = decide_rw_target(cfg, TARGET_UPDATE, is_vboot2);
		STATUS("TRY-RW UPDATE: Updating %s to try on reboot.\n",
		       target);

		if (write_firmware(cfg, image_to, target))
			return UPDATE_ERR_WRITE_FIRMWARE;
		if (set_try_cookies(cfg, target, is_vboot2))
			return UPDATE_ERR_SET_COOKIES;
	} else {
		/* Clear trial cookies for vboot1. */
		if (!is_vboot2 && !cfg->emulation)
			VbSetSystemPropertyInt("fwb_tries", 0);
	}

	/* Do not fail on updating legacy. */
	if (legacy_needs_update(cfg)) {
		has_update = 1;
		STATUS("LEGACY UPDATE: Updating %s.\n", FMAP_RW_LEGACY);
		write_firmware(cfg, image_to, FMAP_RW_LEGACY);
	}

	if (!has_update)
		STATUS("NO UPDATE: No need to update.\n");

	return UPDATE_ERR_DONE;
}

/*
 * The main updater for "RW update".
 * This was also known as --mode=recovery, --wp=1 in legacy updater.
 * Returns UPDATE_ERR_DONE if success, otherwise error.
 */
static enum updater_error_codes update_rw_firmware(
		struct updater_config *cfg,
		struct firmware_image *image_from,
		struct firmware_image *image_to)
{
	STATUS("RW UPDATE: Updating RW sections (%s, %s, %s, and %s).\n",
	       FMAP_RW_SECTION_A, FMAP_RW_SECTION_B, FMAP_RW_SHARED,
	       FMAP_RW_LEGACY);

	INFO("Checking compatibility...\n");
	if (check_compatible_root_key(image_from, image_to))
		return UPDATE_ERR_ROOT_KEY;
	if (check_compatible_tpm_keys(cfg, image_to))
		return UPDATE_ERR_TPM_ROLLBACK;
	/*
	 * TODO(hungte) Speed up by flashing multiple sections in one
	 * command, or provide diff file.
	 */
	if (write_firmware(cfg, image_to, FMAP_RW_SECTION_A) ||
	    write_firmware(cfg, image_to, FMAP_RW_SECTION_B) ||
	    write_firmware(cfg, image_to, FMAP_RW_SHARED) ||
	    write_optional_firmware(cfg, image_to, FMAP_RW_LEGACY, 0, 1))
		return UPDATE_ERR_WRITE_FIRMWARE;

	return UPDATE_ERR_DONE;
}

/*
 * The main updater for "Legacy update".
 * This is equivalent to --mode=legacy.
 * Returns UPDATE_ERR_DONE if success, otherwise error.
 */
static enum updater_error_codes update_legacy_firmware(
		struct updater_config *cfg,
		struct firmware_image *image_to)
{
	STATUS("LEGACY UPDATE: Updating firmware %s.\n", FMAP_RW_LEGACY);

	if (write_firmware(cfg, image_to, FMAP_RW_LEGACY))
		return UPDATE_ERR_WRITE_FIRMWARE;

	return UPDATE_ERR_DONE;
}

/*
 * The main updater for "Full update".
 * This was also known as "--mode=factory" or "--mode=recovery, --wp=0" in
 * legacy updater.
 * Returns UPDATE_ERR_DONE if success, otherwise error.
 */
static enum updater_error_codes update_whole_firmware(
		struct updater_config *cfg,
		struct firmware_image *image_to)
{
	STATUS("FULL UPDATE: Updating whole firmware image(s), RO+RW.\n");

	if (preserve_images(cfg))
		VB2_DEBUG("Failed to preserve some sections - ignore.\n");

	INFO("Checking compatibility...\n");
	if (!cfg->force_update) {
		/* Check if the image_to itself is broken */
		enum rootkey_compat_result r = check_compatible_root_key(
				image_to, image_to);
		if (r != ROOTKEY_COMPAT_OK) {
			ERROR("Target image does not look valid. \n"
			      "Add --force if you really want to use it.");
			return UPDATE_ERR_ROOT_KEY;
		}

		/* Check if the system is going to re-key. */
		r = check_compatible_root_key(&cfg->image_current, image_to);
		/* We only allow re-key to non-dev keys. */
		switch (r) {
		case ROOTKEY_COMPAT_OK:
			break;
		case ROOTKEY_COMPAT_REKEY:
			INFO("Will change firmware signing key.\n");
			break;
		case ROOTKEY_COMPAT_REKEY_TO_DEV:
			ERROR("Re-key to DEV is not allowed. \n"
			      "Add --force if you really want to do that.");
			return UPDATE_ERR_ROOT_KEY;
		default:
			return UPDATE_ERR_ROOT_KEY;
		}
	}
	if (check_compatible_tpm_keys(cfg, image_to))
		return UPDATE_ERR_TPM_ROLLBACK;

	/* FMAP may be different so we should just update all. */
	if (write_firmware(cfg, image_to, NULL) ||
	    write_optional_firmware(cfg, &cfg->ec_image, NULL, 1, 0) ||
	    write_optional_firmware(cfg, &cfg->pd_image, NULL, 1, 0))
		return UPDATE_ERR_WRITE_FIRMWARE;

	return UPDATE_ERR_DONE;
}

/*
 * The main updater to update system firmware using the configuration parameter.
 * Returns UPDATE_ERR_DONE if success, otherwise failure.
 */
enum updater_error_codes update_firmware(struct updater_config *cfg)
{
	int wp_enabled, done = 0;
	enum updater_error_codes r = UPDATE_ERR_UNKNOWN;

	struct firmware_image *image_from = &cfg->image_current,
			      *image_to = &cfg->image;
	if (!image_to->data)
		return UPDATE_ERR_NO_IMAGE;

	if (try_apply_quirk(QUIRK_DAISY_SNOW_DUAL_MODEL, cfg))
		return UPDATE_ERR_PLATFORM;

	STATUS("Target image: %s (RO:%s, RW/A:%s, RW/B:%s).\n",
	     image_to->file_name, image_to->ro_version,
	     image_to->rw_version_a, image_to->rw_version_b);

	if (try_apply_quirk(QUIRK_MIN_PLATFORM_VERSION, cfg))
		return UPDATE_ERR_PLATFORM;

	if (!image_from->data) {
		/*
		 * TODO(hungte) Read only RO_SECTION, VBLOCK_A, VBLOCK_B,
		 * RO_VPD, RW_VPD, RW_NVRAM, RW_LEGACY.
		 */
		INFO("Loading current system firmware...\n");
		if (load_system_firmware(cfg, image_from) != 0)
			return UPDATE_ERR_SYSTEM_IMAGE;
	}
	STATUS("Current system: %s (RO:%s, RW/A:%s, RW/B:%s).\n",
	       image_from->file_name, image_from->ro_version,
	       image_from->rw_version_a, image_from->rw_version_b);

	if (cfg->check_platform && check_compatible_platform(cfg))
		return UPDATE_ERR_PLATFORM;

	wp_enabled = is_write_protection_enabled(cfg);
	STATUS("Write protection: %d (%s; HW=%d, SW=%d).\n", wp_enabled,
	       wp_enabled ? "enabled" : "disabled",
	       get_system_property(SYS_PROP_WP_HW, cfg),
	       get_system_property(SYS_PROP_WP_SW, cfg));

	if (try_apply_quirk(QUIRK_ENLARGE_IMAGE, cfg))
		return UPDATE_ERR_SYSTEM_IMAGE;

	if (try_apply_quirk(QUIRK_EVE_SMM_STORE, cfg))
		return UPDATE_ERR_INVALID_IMAGE;

	if (debugging_enabled)
		print_system_properties(cfg);

	if (cfg->legacy_update)
		return update_legacy_firmware(cfg, image_to);

	if (cfg->try_update) {
		r = update_try_rw_firmware(cfg, image_from, image_to,
					   wp_enabled);
		if (r == UPDATE_ERR_NEED_RO_UPDATE)
			WARN("%s\n", updater_error_messages[r]);
		else
			done = 1;
	}

	if (!done) {
		r = wp_enabled ? update_rw_firmware(cfg, image_from, image_to) :
				 update_whole_firmware(cfg, image_to);
	}

	/* Providing more hints for what to do on failure. */
	if (r == UPDATE_ERR_ROOT_KEY && wp_enabled)
		ERROR("To change keys in RO area, you must first remove "
		      "write protection ( " REMOVE_WP_URL " ).\n");

	return r;
}

/*
 * Allocates and initializes a updater_config object with default values.
 * Returns the newly allocated object, or NULL on error.
 */
struct updater_config *updater_new_config()
{
	struct system_property *props;
	struct updater_config *cfg = (struct updater_config *)calloc(
			1, sizeof(struct updater_config));
	if (!cfg)
		return cfg;
	cfg->image.programmer = PROG_HOST;
	cfg->image_current.programmer = PROG_HOST;
	cfg->ec_image.programmer = PROG_EC;
	cfg->pd_image.programmer = PROG_PD;

	cfg->check_platform = 1;

	props = cfg->system_properties;
	props[SYS_PROP_MAINFW_ACT].getter = host_get_mainfw_act;
	props[SYS_PROP_TPM_FWVER].getter = host_get_tpm_fwver;
	props[SYS_PROP_FW_VBOOT2].getter = host_get_fw_vboot2;
	props[SYS_PROP_PLATFORM_VER].getter = host_get_platform_version;
	props[SYS_PROP_WP_HW].getter = host_get_wp_hw;
	props[SYS_PROP_WP_SW].getter = host_get_wp_sw;

	updater_register_quirks(cfg);
	return cfg;
}

/*
 * Saves everything from stdin to given output file.
 * Returns 0 on success, otherwise failure.
 */
static int save_from_stdin(const char *output)
{
	FILE *in = stdin, *out = fopen(output, "wb");
	char buffer[4096];
	size_t sz;

	assert(in);
	if (!out)
		return -1;

	while (!feof(in)) {
		sz = fread(buffer, 1, sizeof(buffer), in);
		fwrite(buffer, 1, sz, out);
	}
	fclose(out);
	return 0;
}

/*
 * Setup quirks for updating current image.
 *
 * Quirks must be loaded after image loaded because we use image contents to
 * decide default quirks to load. Also, we have to load default quirks first so
 * user can override them using command line.
 *
 * Returns 0 on success, otherwise number of failures.
 */
static int updater_setup_quirks(struct updater_config *cfg,
				const struct updater_config_arguments *arg)
{
	int errorcnt = 0;
	const char *quirks = updater_get_default_quirks(cfg);

	if (quirks)
		errorcnt += !!setup_config_quirks(quirks, cfg);
	if (arg->quirks)
		errorcnt += !!setup_config_quirks(arg->quirks, cfg);
	return errorcnt;
}

/*
 * Loads images into updater configuration.
 * Returns 0 on success, otherwise number of failures.
 */
static int updater_load_images(struct updater_config *cfg,
			       const struct updater_config_arguments *arg,
			       const char *image,
			       const char *ec_image,
			       const char *pd_image)
{
	int errorcnt = 0;
	struct archive *ar = cfg->archive;

	if (!cfg->image.data && image) {
		if (image && strcmp(image, "-") == 0) {
			INFO("Reading image from stdin...\n");
			image = updater_create_temp_file(cfg);
			if (image)
				errorcnt += !!save_from_stdin(image);
		}
		errorcnt += !!load_firmware_image(&cfg->image, image, ar);
		if (!errorcnt)
			errorcnt += updater_setup_quirks(cfg, arg);
	}
	if (arg->host_only)
		return errorcnt;

	if (!cfg->ec_image.data && ec_image)
		errorcnt += !!load_firmware_image(&cfg->ec_image, ec_image, ar);
	if (!cfg->pd_image.data && pd_image)
		errorcnt += !!load_firmware_image(&cfg->pd_image, pd_image, ar);
	return errorcnt;
}

/*
 * Writes a firmware image to specified file.
 * Returns 0 on success, otherwise failure.
 */
static int updater_output_image(const struct firmware_image *image,
				const char *fname, const char *root)
{
	int r = 0;
	char *fpath;

	if (!image->data)
		return 0;

	ASPRINTF(&fpath, "%s/%s", root, fname);
	r = vb2_write_file(fpath, image->data, image->size);
	if (r)
		ERROR("Failed writing firmware image to: %s\n", fpath);
	else
		printf("Firmware image saved in: %s\n", fpath);

	free(fpath);
	return !!r;
}

/*
 * Applies white label information to an existing model config.
 * Returns 0 on success, otherwise failure.
 */
static int updater_apply_white_label(struct updater_config *cfg,
				     struct model_config *model,
				     const char *signature_id)
{
	const char *tmp_image = NULL;

	assert(model->is_white_label);
	if (!signature_id) {
		if (cfg->image_current.data) {
			tmp_image = updater_create_temp_file(cfg);
			if (!tmp_image)
				return 1;
			if (vb2_write_file(tmp_image, cfg->image_current.data,
					    cfg->image_current.size)) {
				ERROR("Failed writing temporary image file.\n");
				return 1;
			}
		} else {
			INFO("Loading system firmware for white label...\n");
			load_system_firmware(cfg, &cfg->image_current);
			tmp_image = cfg->image_current.file_name;
		}
		if (!tmp_image) {
			ERROR("Failed to get system current firmware\n");
			return 1;
		}
	}
	return !!model_apply_white_label(
			model, cfg->archive, signature_id, tmp_image);
}

/*
 * Setup what the updater has to do against an archive.
 * Returns number of failures, or 0 on success.
 */
static int updater_setup_archive(
		struct updater_config *cfg,
		const struct updater_config_arguments *arg,
		struct manifest *manifest,
		int is_factory)
{
	int errorcnt = 0;
	struct archive *ar = cfg->archive;
	const struct model_config *model;

	if (arg->do_manifest) {
		assert(!arg->image);
		print_json_manifest(manifest);
		/* No additional error. */
		return errorcnt;
	}

	model = manifest_find_model(manifest, arg->model);
	if (!model)
		return ++errorcnt;

	/* Load images now so we can get quirks in WL checks. */
	errorcnt += updater_load_images(
			cfg, arg, model->image, model->ec_image,
			model->pd_image);

	if (model->is_white_label && !manifest->has_keyset) {
		/*
		 * Developers running unsigned updaters (usually local build)
		 * won't be able match any white label tags.
		 */
		WARN("No keysets found - this is probably a local build of \n"
		     "unsigned firmware updater. Skip applying white label.");
	} else if (model->is_white_label) {
		/*
		 * It is fine to fail in updater_apply_white_label for factory
		 * mode so we are not checking the return value; instead we
		 * verify if the patches do contain new root key.
		 */
		updater_apply_white_label(cfg, (struct model_config *)model,
					  arg->signature_id);
		if (!model->patches.rootkey) {
			if (is_factory ||
			    is_write_protection_enabled(cfg) ||
			    get_config_quirk(QUIRK_ALLOW_EMPTY_WLTAG, cfg)) {
				WARN("No VPD for white label.\n");
			} else {
				ERROR("Need VPD set for white label.\n");
				return ++errorcnt;
			}
		}
	}
	errorcnt += patch_image_by_model(&cfg->image, model, ar);
	return errorcnt;
}

/*
 * Helper function to setup an allocated updater_config object.
 * Returns number of failures, or 0 on success.
 */
int updater_setup_config(struct updater_config *cfg,
			 const struct updater_config_arguments *arg,
			 int *do_update)
{
	int errorcnt = 0;
	int check_single_image = 0, check_wp_disabled = 0;
	int do_output = 0;
	const char *archive_path = arg->archive;

	/* Setup values that may change output or decision of other argument. */
	cfg->verbosity = arg->verbosity;
	cfg->fast_update = arg->fast_update;
	cfg->factory_update = arg->is_factory;
	if (arg->force_update)
		cfg->force_update = 1;

	/* Check incompatible options and return early. */
	if (arg->do_manifest) {
		if (!!arg->archive == !!arg->image) {
			ERROR("--manifest needs either -a or -i\n");
			return ++errorcnt;
		}
		if (arg->archive && (arg->ec_image || arg->pd_image)) {
			ERROR("--manifest for archive (-a) does not accept \n"
			      "additional images (--ec_image, --pd_image).");
			return ++errorcnt;
		}
		*do_update = 0;
	}
	if (arg->repack || arg->unpack) {
		if (!arg->archive) {
			ERROR("--{re,un}pack needs --archive.\n");
			return ++errorcnt;
		}
		*do_update = 0;
	}

	/* Setup update mode. */
	if (arg->try_update)
		cfg->try_update = 1;
	if (arg->mode) {
		if (strcmp(arg->mode, "autoupdate") == 0) {
			cfg->try_update = 1;
		} else if (strcmp(arg->mode, "recovery") == 0) {
			cfg->try_update = 0;
		} else if (strcmp(arg->mode, "legacy") == 0) {
			cfg->legacy_update = 1;
		} else if (strcmp(arg->mode, "factory") == 0 ||
			   strcmp(arg->mode, "factory_install") == 0) {
			cfg->factory_update = 1;
		} else if (strcmp(arg->mode, "output") == 0) {
			do_output = 1;
		} else {
			errorcnt++;
			ERROR("Invalid mode: %s\n", arg->mode);
		}
	}
	if (cfg->factory_update) {
		/* factory_update must be processed after arg->mode. */
		check_wp_disabled = 1;
		cfg->try_update = 0;
	}

	/* Setup properties and fields that do not have external dependency. */
	if (arg->programmer) {
		check_single_image = 1;
		cfg->image.programmer = arg->programmer;
		cfg->image_current.programmer = arg->programmer;
		VB2_DEBUG("AP (host) programmer changed to %s.\n",
			  arg->programmer);
	}
	if (arg->sys_props)
		override_properties_from_list(arg->sys_props, cfg);
	if (arg->write_protection) {
		/* arg->write_protection must be done after arg->sys_props. */
		int r = strtol(arg->write_protection, NULL, 0);
		override_system_property(SYS_PROP_WP_HW, cfg, r);
		override_system_property(SYS_PROP_WP_SW, cfg, r);
	}

	/* Set up archive and load images. */
	if (arg->emulation) {
		/* Process emulation file first. */
		cfg->emulation = arg->emulation;
		VB2_DEBUG("Using file %s for emulation.\n", arg->emulation);
		errorcnt += !!load_firmware_image(
				&cfg->image_current, arg->emulation, NULL);
	}

	/* Always load images specified from command line directly. */
	errorcnt += updater_load_images(
			cfg, arg, arg->image, arg->ec_image, arg->pd_image);

	if (!archive_path)
		archive_path = ".";
	cfg->archive = archive_open(archive_path);
	if (!cfg->archive) {
		ERROR("Failed to open archive: %s\n", archive_path);
		return ++errorcnt;
	}

	/* Process archives which may not have valid contents. */
	if (arg->repack || arg->unpack) {
		const char *work_name = arg->repack ? arg->repack : arg->unpack;
		struct archive *from, *to, *work;

		work = archive_open(work_name);
		if (arg->repack) {
			from = work;
			to = cfg->archive;
		} else {
			to = work;
			from = cfg->archive;
		}
		if (!work) {
			ERROR("Failed to open: %s\n", work_name);
			return ++errorcnt;
		}
		errorcnt += !!archive_copy(from, to);
		/* TODO(hungte) Update manifest after copied. */
		archive_close(work);
		return errorcnt;
	}

	/* Load images from archive. */
	if (arg->archive) {
		struct manifest *m = new_manifest_from_archive(cfg->archive);
		if (m) {
			errorcnt += updater_setup_archive(
					cfg, arg, m, cfg->factory_update);
			delete_manifest(m);
		} else {
			ERROR("Failure in archive: %s\n", arg->archive);
			++errorcnt;
		}
	} else if (arg->do_manifest) {
		char name[] = "default";
		struct model_config model = {
			.name = name,
			.image = arg->image,
			.ec_image = arg->ec_image,
			.pd_image = arg->pd_image,
		};
		struct manifest manifest = {
			.num = 1,
			.models = &model,
		};
		assert(model.image);
		print_json_manifest(&manifest);
	}

	/*
	 * Images should be loaded now (either in first updater_load_images or
	 * second call from updater_setup_archive) and quirks should be loaded.
	 * For invocation without image, we want to get quirks now.
	 */
	if (!cfg->image.data && arg->quirks)
		errorcnt += !!setup_config_quirks(arg->quirks, cfg);

	/* Additional checks. */
	if (check_single_image && (cfg->ec_image.data || cfg->pd_image.data)) {
		errorcnt++;
		ERROR("EC/PD images are not supported in current mode.\n");
	}
	if (check_wp_disabled && is_write_protection_enabled(cfg)) {
		errorcnt++;
		ERROR("Please remove write protection for factory mode \n"
		      "( " REMOVE_WP_URL " ).");
	}
	if (!errorcnt && do_output) {
		const char *r = arg->output_dir;
		if (!r)
			r = ".";
		/* TODO(hungte) Remove bios.bin when migration is done. */
		errorcnt += updater_output_image(&cfg->image, "bios.bin", r);
		errorcnt += updater_output_image(&cfg->image, "image.bin", r);
		errorcnt += updater_output_image(&cfg->ec_image, "ec.bin", r);
		errorcnt += updater_output_image(&cfg->pd_image, "pd.bin", r);
		*do_update = 0;
	}
	return errorcnt;
}

/*
 * Releases all resources in an updater configuration object.
 */
void updater_delete_config(struct updater_config *cfg)
{
	assert(cfg);
	free_firmware_image(&cfg->image);
	free_firmware_image(&cfg->image_current);
	free_firmware_image(&cfg->ec_image);
	free_firmware_image(&cfg->pd_image);
	updater_remove_all_temp_files(cfg);
	if (cfg->archive)
		archive_close(cfg->archive);
	free(cfg);
}