known device/sram data persistence working
This commit is contained in:
jaseg
parent
66f9e82c5c
commit
eb481f1cda
5 changed files with 53 additions and 14 deletions
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@ -33,6 +33,17 @@ MEMORY
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/* Include the common ld script. */
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INCLUDE libopencm3_stm32f4.ld
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/* Extra stuff */
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SECTIONS
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{
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.backup_sram : {
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. = ALIGN(4);
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__backup_sram_start = .;
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*(.backup_sram)
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__backup_sram_end = .;
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} >backup
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}
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PROVIDE(_ram_start = ORIGIN(ram));
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PROVIDE(_ram_end = ORIGIN(ram) + LENGTH(ram));
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PROVIDE(_rom_start = ORIGIN(rom));
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@ -3,6 +3,7 @@ import threading
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import binascii
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import re
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import os
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import time
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import serial
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import gi
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@ -136,11 +137,11 @@ def run_pairing_gui(port, baudrate, debug=False):
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raise SystemError('Unknown noise error')
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with open(known_devices_file, 'a') as f:
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f.write(noise.remote_fingerprint)
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f.write(f'{noise.remote_fingerprint} # added {time.ctime()}\n')
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else:
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with open(known_devices_file) as f:
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known_devices = [ l.strip() for l in f.readlines() if not l[0] == '#' ]
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known_devices = [ l.strip().partition('#')[0].strip() for l in f.readlines() if not l[0] == '#' ]
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if noise.remote_fingerprint not in known_devices:
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raise ValueError('Remote host is untrusted but seems to trust us.')
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23
src/demo.c
23
src/demo.c
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@ -38,6 +38,7 @@
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#include <libopencm3/stm32/timer.h>
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#include <libopencm3/stm32/otg_hs.h>
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#include <libopencm3/stm32/otg_fs.h>
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#include <libopencm3/stm32/pwr.h>
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#include <libopencm3/stm32/dma.h>
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#include <libopencm3/cm3/nvic.h>
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#include <libopencmsis/core_cm3.h>
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@ -56,7 +57,9 @@
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static struct NoiseState noise_state;
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static uint8_t remote_key_reference[CURVE25519_KEY_LEN];
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static uint8_t remote_key_reference[BLAKE2S_HASH_SIZE] __attribute__((section(".backup_sram")));
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static uint8_t local_key[CURVE25519_KEY_LEN] __attribute__((section(".backup_sram")));
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static uint8_t identity_key_valid __attribute__((section(".backup_sram"))) = 0;
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void _fini(void);
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@ -81,6 +84,9 @@ static void clock_setup(void) {
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rcc_periph_clock_enable(RCC_DMA2);
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rcc_periph_clock_enable(RCC_DMA1);
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rcc_periph_clock_enable(RCC_PWR);
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rcc_periph_clock_enable(RCC_BKPSRAM);
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rcc_periph_clock_enable(RCC_RNG);
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}
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@ -413,6 +419,8 @@ int main(void)
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{
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clock_setup();
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gpio_setup();
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pwr_disable_backup_domain_write_protect();
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PWR_CSR |= PWR_CSR_BRE; /* Enable backup SRAM battery power regulator */
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/* provides time_curr_us to usbh_poll function */
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tim6_setup();
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@ -447,12 +455,17 @@ int main(void)
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LOG_PRINTF("Initializing RNG...\n");
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rand_init();
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noise_state_init(&noise_state, remote_key_reference);
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noise_state_init(&noise_state, remote_key_reference, local_key);
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/* FIXME load remote key from backup memory */
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/* FIXME only run this on first boot and persist key in backup sram. Allow reset via jumper-triggered factory reset function. */
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LOG_PRINTF("Generating identity key...\n");
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if (generate_identity_key(&noise_state))
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LOG_PRINTF("Error generating identiy key\n");
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if (!identity_key_valid) {
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LOG_PRINTF("Generating identity key...\n");
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if (generate_identity_key(&noise_state)) {
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LOG_PRINTF("Error generating identiy key\n");
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} else {
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identity_key_valid = 1;
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}
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}
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int poll_ctr = 0;
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while (23) {
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24
src/noise.c
24
src/noise.c
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@ -3,6 +3,9 @@
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#include "noise.h"
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#include "packet_interface.h"
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#include "rand_stm32.h"
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#include "crypto/noise-c/src/crypto/blake2/blake2s.h"
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#define HANDLE_NOISE_ERROR(x, msg) do { \
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@ -20,12 +23,13 @@ volatile uint8_t host_packet_buf[MAX_HOST_PACKET_SIZE];
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volatile int host_packet_length = 0;
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void noise_state_init(struct NoiseState *st, uint8_t *remote_key_reference) {
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void noise_state_init(struct NoiseState *st, uint8_t *remote_key_reference, uint8_t *local_key) {
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st->handshake_state = HANDSHAKE_UNINITIALIZED;
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st->handshake = NULL;
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st->tx_cipher = NULL;
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st->rx_cipher = NULL;
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st->remote_key_reference = remote_key_reference;
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st->local_key = local_key;
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st->failed_handshakes = 0;
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}
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@ -51,7 +55,7 @@ int start_protocol_handshake(struct NoiseState *st) {
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HANDLE_NOISE_ERROR(noise_handshakestate_new_by_name(&handshake, "Noise_XX_25519_ChaChaPoly_BLAKE2s", NOISE_ROLE_RESPONDER), "instantiating handshake pattern");
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NoiseDHState *dh = noise_handshakestate_get_local_keypair_dh(handshake);
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HANDLE_NOISE_ERROR(noise_dhstate_set_keypair_private(dh, st->local_key, sizeof(st->local_key)), "loading local private keys");
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HANDLE_NOISE_ERROR(noise_dhstate_set_keypair_private(dh, st->local_key, CURVE25519_KEY_LEN), "loading local private keys");
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HANDLE_NOISE_ERROR(noise_handshakestate_start(handshake), "starting handshake");
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@ -74,7 +78,7 @@ int generate_identity_key(struct NoiseState *st) {
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uint8_t unused[CURVE25519_KEY_LEN]; /* the noise api is a bit bad here. */
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memset(st->local_key, 0, sizeof(st->local_key));
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HANDLE_NOISE_ERROR(noise_dhstate_get_keypair(dh, st->local_key, sizeof(st->local_key), unused, sizeof(unused)), "saving key pair");
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HANDLE_NOISE_ERROR(noise_dhstate_get_keypair(dh, st->local_key, CURVE25519_KEY_LEN, unused, sizeof(unused)), "saving key pair");
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return 0;
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errout:
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@ -146,7 +150,14 @@ int try_continue_noise_handshake(struct NoiseState *st, uint8_t *buf, size_t len
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HANDLE_NOISE_ERROR(noise_dhstate_get_public_key(remote_dh, st->remote_key, sizeof(st->remote_key)), "getting remote pubkey");
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if (!memcmp(st->remote_key, st->remote_key_reference, sizeof(st->remote_key))) { /* keys match */
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/* TODO support list of known remote hosts here instead of just one */
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uint8_t remote_fp[BLAKE2S_HASH_SIZE];
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BLAKE2s_context_t bc;
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BLAKE2s_reset(&bc);
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BLAKE2s_update(&bc, st->remote_key, sizeof(st->remote_key));
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BLAKE2s_finish(&bc, remote_fp);
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if (!memcmp(remote_fp, st->remote_key_reference, sizeof(remote_fp))) { /* keys match */
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uint8_t response = REPORT_PAIRING_SUCCESS;
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if (send_encrypted_message(st, &response, sizeof(response)))
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LOG_PRINTF("Error sending pairing response packet\n");
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@ -177,7 +188,10 @@ errout:
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}
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void persist_remote_key(struct NoiseState *st) {
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memcpy(st->remote_key_reference, st->remote_key, sizeof(st->remote_key));
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BLAKE2s_context_t bc;
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BLAKE2s_reset(&bc);
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BLAKE2s_update(&bc, st->remote_key, sizeof(st->remote_key));
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BLAKE2s_finish(&bc, st->remote_key_reference);
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st->handshake_state = HANDSHAKE_DONE_KNOWN_HOST;
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}
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@ -30,7 +30,7 @@ struct NoiseState {
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NoiseHandshakeState *handshake;
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enum handshake_state handshake_state;
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NoiseCipherState *tx_cipher, *rx_cipher;
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uint8_t local_key[CURVE25519_KEY_LEN];
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uint8_t *local_key;
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uint8_t remote_key[CURVE25519_KEY_LEN];
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uint8_t *remote_key_reference;
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uint8_t handshake_hash[BLAKE2S_HASH_SIZE];
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@ -39,7 +39,7 @@ struct NoiseState {
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void uninit_handshake(struct NoiseState *st, enum handshake_state new_state);
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void noise_state_init(struct NoiseState *st, uint8_t *remote_key_reference);
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void noise_state_init(struct NoiseState *st, uint8_t *remote_key_reference, uint8_t *local_key);
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void persist_remote_key(struct NoiseState *st);
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int start_protocol_handshake(struct NoiseState *st);
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int reset_protocol_handshake(struct NoiseState *st);
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