trezor-mcu/firmware/reset.c

/*
 * This file is part of the TREZOR project.
 *
 * Copyright (C) 2014 Pavol Rusnak <stick@satoshilabs.com>
 *
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "reset.h"
#include "storage.h"
#include "rng.h"
#include "sha2.h"
#include "messages.h"
#include "fsm.h"
#include "layout2.h"
#include "types.pb.h"
#include "protect.h"
#include "bip39.h"
#include "util.h"

static uint32_t strength;
static uint8_t  int_entropy[32];
static bool     awaiting_entropy = false;

void reset_init(bool display_random, uint32_t _strength, bool passphrase_protection, bool pin_protection, const char *language, const char *label)
{
	if (_strength != 128 && _strength != 192 && _strength != 256) {
		fsm_sendFailure(FailureType_Failure_SyntaxError, "Invalid strength (has to be 128, 192 or 256 bits)");
		layoutHome();
		return;
	}

	strength = _strength;

	random_buffer(int_entropy, 32);

	char ent_str[4][17];
	data2hex(int_entropy     , 8, ent_str[0]);
	data2hex(int_entropy +  8, 8, ent_str[1]);
	data2hex(int_entropy + 16, 8, ent_str[2]);
	data2hex(int_entropy + 24, 8, ent_str[3]);

	if (display_random) {
		layoutDialogSwipe(DIALOG_ICON_INFO, "Cancel", "Continue", NULL, "Internal entropy:", ent_str[0], ent_str[1], ent_str[2], ent_str[3], NULL);
		if (!protectButton(ButtonRequestType_ButtonRequest_ResetDevice, false)) {
			fsm_sendFailure(FailureType_Failure_ActionCancelled, "Reset cancelled");
			layoutHome();
			return;
		}
	}

	if (pin_protection && !protectChangePin()) {
		fsm_sendFailure(FailureType_Failure_ActionCancelled, "PIN change failed");
		layoutHome();
		return;
	}

	storage.has_passphrase_protection = true;
	storage.passphrase_protection = passphrase_protection;
	storage_setLanguage(language);
	storage_setLabel(label);

	EntropyRequest resp;
	memset(&resp, 0, sizeof(EntropyRequest));
	msg_write(MessageType_MessageType_EntropyRequest, &resp);
	awaiting_entropy = true;
}

static char current_word[10];

void reset_entropy(const uint8_t *ext_entropy, uint32_t len)
{
	if (!awaiting_entropy) {
		fsm_sendFailure(FailureType_Failure_UnexpectedMessage, "Not in Reset mode");
		return;
	}
	SHA256_CTX ctx;
	sha256_Init(&ctx);
	sha256_Update(&ctx, int_entropy, 32);
	sha256_Update(&ctx, ext_entropy, len);
	sha256_Final(int_entropy, &ctx);
	strlcpy(storage.mnemonic, mnemonic_from_data(int_entropy, strength / 8), sizeof(storage.mnemonic));
	memset(int_entropy, 0, 32);
	awaiting_entropy = false;

	int pass, idx, i = 0, j;

	for (pass = 0; pass < 2; pass++) {
		i = 0;
		for (idx = 0; idx < (int)strength/32*3; idx++) {
			// copy current_word
			j = 0;
			while (storage.mnemonic[i] != ' ' && storage.mnemonic[i] != 0 && j + 1 < (int)sizeof(current_word)) {
				current_word[j] = storage.mnemonic[i];
				i++; j++;
			}
			current_word[j] = 0; if (storage.mnemonic[i] != 0) i++;
			char descbuf[] = "__. word is:";
			char *desc = descbuf;
			if (idx + 1 < 10) {
				desc++;
			} else {
				descbuf[0] = '0' + (idx + 1) / 10;
			}
			descbuf[1] = '0' + (idx + 1) % 10;
			if (idx + 1 == (int)strength/32*3) { // last word
				if (pass == 1) {
					layoutDialogSwipe(DIALOG_ICON_INFO, NULL, "Finish", NULL, "Please check the seed", NULL, desc, NULL, current_word, NULL);
				} else {
					layoutDialogSwipe(DIALOG_ICON_INFO, NULL, "Again", NULL, "Write down the seed", NULL, desc, NULL, current_word, NULL);
				}
			} else {
				if (pass == 1) {
					layoutDialogSwipe(DIALOG_ICON_INFO, NULL, "Next", NULL, "Please check the seed", NULL, desc, NULL, current_word, NULL);
				} else {
					layoutDialogSwipe(DIALOG_ICON_INFO, NULL, "Next", NULL, "Write down the seed", NULL, desc, NULL, current_word, NULL);
				}
			}
			if (!protectButton(ButtonRequestType_ButtonRequest_ConfirmWord, true)) {
				storage_reset();
				layoutHome();
				return;
			}
		}
	}

	storage.has_mnemonic = true;
	storage_commit();
	fsm_sendSuccess("Device reset");
	layoutHome();
}

uint32_t reset_get_int_entropy(uint8_t *entropy) {
	memcpy(entropy, int_entropy, 32);
	return 32;
}

const char *reset_get_word(void) {
	return current_word;
}