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// SPDX-FileCopyrightText: 2018 Coinkite, Inc. <coldcardwallet.com>
// SPDX-License-Identifier: GPL-3.0-only
//
/*
* (c) Copyright 2018 by Coinkite Inc. This file is part of Coldcard <coldcardwallet.com>
* and is covered by GPLv3 license found in COPYING.
*
* verify.c -- Check signatures on firmware images in flash.
*
*/
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include "delay.h"
#include "firmware-keys.h"
#include "hash.h"
#include "se.h"
#include "se-config.h"
#include "sha256.h"
#include "uECC.h"
#include "utils.h"
#include "se-atecc608a.h"
#include "verify.h"
secresult verify_header(passport_firmware_header_t *hdr)
{
if (hdr->info.magic != FW_HEADER_MAGIC) goto fail;
if (hdr->info.timestamp == 0) goto fail;
if (hdr->info.fwversion[0] == 0x0) goto fail;
if (hdr->info.fwlength < FW_HEADER_SIZE) goto fail;
#ifdef USE_CRYPTO
// if (hdr->signature.pubkey1 == 0) goto fail;
if ((hdr->signature.pubkey1 != FW_USER_KEY) && (hdr->signature.pubkey1 > FW_MAX_PUB_KEYS)) goto fail;
if (hdr->signature.pubkey1 != FW_USER_KEY)
{
// if (hdr->signature.pubkey2 == 0) goto fail;
if (hdr->signature.pubkey2 > FW_MAX_PUB_KEYS) goto fail;
}
#endif /* USE_CRYPTO */
return SEC_TRUE;
fail:
return SEC_FALSE;
}
secresult verify_signature(
passport_firmware_header_t *hdr,
uint8_t *fw_hash,
uint32_t hashlen
)
{
#ifdef USE_CRYPTO
int rc;
if (hdr->signature.pubkey1 == FW_USER_KEY)
{
uint8_t user_public_key[72] = {0};
/*
* It looks like the user signed this firmware so, in order to
* validate, we need to get the public key from the SE.
*/
se_pair_unlock();
rc = se_read_data_slot(KEYNUM_user_fw_pubkey, user_public_key, sizeof(user_public_key));
if (rc < 0)
return SEC_FALSE;
rc = uECC_verify(user_public_key,
fw_hash, hashlen,
hdr->signature.signature1, uECC_secp256k1());
if (rc == 0)
return SEC_FALSE;
}
else
{
rc = uECC_verify(approved_pubkeys[hdr->signature.pubkey1],
fw_hash, hashlen,
hdr->signature.signature1, uECC_secp256k1());
if (rc == 0)
return SEC_FALSE;
rc = uECC_verify(approved_pubkeys[hdr->signature.pubkey2],
fw_hash, hashlen,
hdr->signature.signature2, uECC_secp256k1());
if (rc == 0)
return SEC_FALSE;
}
return SEC_TRUE;
#else
return SEC_TRUE;
#endif /* USE_CRYPTO */
}
secresult verify_current_firmware(
bool process_led
)
{
uint8_t fw_hash[HASH_LEN];
passport_firmware_header_t *fwhdr = (passport_firmware_header_t *)FW_HDR;
uint8_t *fwptr = (uint8_t *)fwhdr + FW_HEADER_SIZE;
if (!verify_header(fwhdr))
return ERR_INVALID_FIRMWARE_HEADER;
hash_fw(&fwhdr->info, fwptr, fwhdr->info.fwlength, fw_hash, sizeof(fw_hash));
if (verify_signature(fwhdr, fw_hash, sizeof(fw_hash)) == SEC_FALSE)
return ERR_INVALID_FIRMWARE_SIGNATURE;
#ifdef PRODUCTION_BUILD
if (process_led)
{
int rc;
uint8_t board_hash[HASH_LEN];
hash_board(fw_hash, sizeof(fw_hash), board_hash, sizeof(board_hash));
rc = se_set_gpio_secure(board_hash);
if (rc < 0)
return ERR_UNABLE_TO_UPDATE_FIRMWARE_HASH_IN_SE;
}
#endif /* PRODUCTION_BUILD */
return SEC_TRUE;
}
// EOF