trezor-firmware/embed/firmware/bl_check.c

/*
 * This file is part of the TREZOR project, https://trezor.io/
 *
 * Copyright (c) SatoshiLabs
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdint.h>
#include <string.h>
#include "common.h"
#include "flash.h"
#include "blake2s.h"

// symbols from bootloader.bin => bootloader.o
extern const uint32_t _binary_embed_firmware_bootloader_bin_start;
extern const uint32_t _binary_embed_firmware_bootloader_bin_size;

/*
static secbool known_bootloader(const uint8_t *hash, int len) {
    if (len != 32) return secfalse;
    // bootloader-2.0.1.bin (padded with 0x00)
    if (0 == memcmp(hash, "\x91\x37\x46\xd0\x2d\xa7\xc4\xbe\x1d\xae\xef\xb0\x9b\x4e\x31\x88\xed\x38\x23\x5e\x0e\x31\xa7\x8c\x01\xde\x4e\xcc\xc2\xd6\x36\xb3", 32)) return sectrue;
    // bootloader-2.0.1.bin (padded with 0xff)
    if (0 == memcmp(hash, "\x2f\xdb\xde\x94\x0a\xd8\x91\x1c\xbd\x07\xb0\xba\x06\x2c\x90\x84\x02\xec\x95\x19\xde\x52\x8d\x4b\xe9\xb9\xed\x30\x71\x91\xb4\xd3", 32)) return sectrue;
    // bootloader-2.0.2.bin (padded with 0x00)
    if (0 == memcmp(hash, "\x2e\xf7\x47\xf8\x49\x87\x1e\xc8\xc6\x01\x35\xd6\x32\xe5\x5a\xd1\x56\x18\xf8\x64\x87\xb7\xaa\x7c\x62\x0e\xc3\x0d\x25\x69\x4e\x18", 32)) return sectrue;
    // bootloader-2.0.2.bin (padded with 0xff)
    if (0 == memcmp(hash, "\xcc\x6b\x35\xc3\x8f\x29\x5c\xbd\x7d\x31\x69\xaf\xae\xf1\x61\x01\xef\xbe\x9f\x3b\x0a\xfd\xc5\x91\x70\x9b\xf5\xa0\xd5\xa4\xc5\xe0", 32)) return sectrue;
    return secfalse;
}
*/

static secbool latest_bootloader(const uint8_t *hash, int len) {
    if (len != 32) return secfalse;
    // bootloader.bin (padded with 0x00)
    if (0 == memcmp(hash, "\x2e\xf7\x47\xf8\x49\x87\x1e\xc8\xc6\x01\x35\xd6\x32\xe5\x5a\xd1\x56\x18\xf8\x64\x87\xb7\xaa\x7c\x62\x0e\xc3\x0d\x25\x69\x4e\x18", 32)) return sectrue;
    // bootloader.bin (padded with 0xff)
    if (0 == memcmp(hash, "\xcc\x6b\x35\xc3\x8f\x29\x5c\xbd\x7d\x31\x69\xaf\xae\xf1\x61\x01\xef\xbe\x9f\x3b\x0a\xfd\xc5\x91\x70\x9b\xf5\xa0\xd5\xa4\xc5\xe0", 32)) return sectrue;
    return secfalse;
}

#define BACKLIGHT_NORMAL  150

void check_and_replace_bootloader(void)
{
    // compute current bootloader hash
    uint8_t hash[BLAKE2S_DIGEST_LENGTH];
    const uint32_t bl_len = 128 * 1024;
    const void *bl_data = flash_get_address(FLASH_SECTOR_BOOTLOADER, 0, bl_len);
    blake2s(bl_data, bl_len, hash, BLAKE2S_DIGEST_LENGTH);

    // don't whitelist the valid bootloaders for now
    // ensure(known_bootloader(hash, BLAKE2S_DIGEST_LENGTH), "Unknown bootloader detected");

    // do we have the latest bootloader?
    if (sectrue == latest_bootloader(hash, BLAKE2S_DIGEST_LENGTH)) {
        return;
    }

    // replace bootloader with the latest one
    const uint32_t *data = (const uint32_t *)&_binary_embed_firmware_bootloader_bin_start;
    const uint32_t len = (const uint32_t)&_binary_embed_firmware_bootloader_bin_size;
    ensure(flash_erase(FLASH_SECTOR_BOOTLOADER), NULL);
    ensure(flash_unlock_write(), NULL);
    for (int i = 0; i < len / sizeof(uint32_t); i++) {
        ensure(flash_write_word(FLASH_SECTOR_BOOTLOADER, i * sizeof(uint32_t), data[i]), NULL);
    }
    for (int i = len / sizeof(uint32_t); i < 128 * 1024 / sizeof(uint32_t); i++) {
        ensure(flash_write_word(FLASH_SECTOR_BOOTLOADER, i * sizeof(uint32_t), 0x00000000), NULL);
    }
    ensure(flash_lock_write(), NULL);
}