lora-irrigation/rs485hid/strobe_pki.c

/*-
 * Copyright 2022 John-Mark Gurney.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <stdint.h>

#include <x25519.h>

#include <board/simpflash.h>

#include <strobe_rng_init.h> /* roundup */

#include <strobe_pki.h>

uint8_t keyvalid;

static const uint8_t privkey[roundup(EC_PRIVATE_BYTES, sizeof(uint8_t)) / sizeof(uint8_t)] __attribute__ ((section (".savekeys"))) = {
#if 0
	0xae, 0xe7, 0xdd, 0x04, 0x84, 0xb3, 0xcd, 0x3c,
	0xef, 0x25, 0x71, 0x83, 0xc4, 0x6c, 0x5d, 0x3c,
	0xee, 0x98, 0xee, 0x79, 0xf2, 0x97, 0x6a, 0xe8,
	0x39, 0xec, 0x7d, 0xe8, 0x23, 0xe7, 0x20, 0xdb,
#endif
};
#include <public_key.h>

void
get_pubkey(uint8_t pubkey[EC_PUBLIC_BYTES])
{

	x25519_base(pubkey, privkey, 1);
}

struct strobepkikey
get_key(void)
{
	struct strobepkikey spk;
	uint8_t key[sizeof privkey] = {};
	uint8_t keyf[sizeof privkey] = {};
	int r;

	memset(keyf, 0xff, sizeof keyf);

	if (memcmp(key, privkey, sizeof privkey) == 0 ||
	    memcmp(keyf, privkey, sizeof privkey) == 0) {
		/* Generate new key */
		do {
			r = strobe_randomize((uint8_t *)key, sizeof key);
			if (r < 0)
				continue;
		} while (r != 0);

		/* and write it. */
		doflash(privkey, key, sizeof key);
	}

	spk = (struct strobepkikey){
		.privkey.pkt = (void *)(uintptr_t)privkey,
		.privkey.pktlen = EC_PRIVATE_BYTES,
		.pubkey.pkt = (void *)(uintptr_t)pubkey,
		.pubkey.pktlen = EC_PUBLIC_BYTES,
	};

	return spk;
}