bool signerAtsha204SoftSignMsg(MyMessage &msg) {
// If we cannot fit any signature in the message, refuse to sign it
if (mGetLength(msg) > MAX_PAYLOAD-2) {
DEBUG_SIGNING_PRINTBUF(F("Message too large"), NULL, 0);
return false;
}
// Calculate signature of message
mSetSigned(msg, 1); // make sure signing flag is set before signature is calculated
signerCalculateSignature(msg);
if (DO_WHITELIST(msg.destination)) {
// Salt the signature with the senders nodeId and the (hopefully) unique serial The Creator has provided
_signing_sha256.init();
for (int i=0; i<32; i++) _signing_sha256.write(_signing_hmac[i]);
_signing_sha256.write(msg.sender);
for (int i=0; i<SHA204_SERIAL_SZ; i++) _signing_sha256.write(_signing_node_serial_info[i]);
memcpy(_signing_hmac, _signing_sha256.result(), 32);
DEBUG_SIGNING_PRINTBUF(F("SHA256: "), _signing_hmac, 32);
DEBUG_SIGNING_PRINTBUF(F("Signature salted with serial"), NULL, 0);
}
// Overwrite the first byte in the signature with the signing identifier
_signing_hmac[0] = SIGNING_IDENTIFIER;
// Transfer as much signature data as the remaining space in the message permits
memcpy(&msg.data[mGetLength(msg)], _signing_hmac, MAX_PAYLOAD-mGetLength(msg));
DEBUG_SIGNING_PRINTBUF(F("Signature in message: "), (uint8_t*)&msg.data[mGetLength(msg)], MAX_PAYLOAD-mGetLength(msg));
return true;
}
bool signerAtsha204SoftGetNonce(MyMessage &msg) {
DEBUG_SIGNING_PRINTBUF(F("Signing backend: ATSHA204Soft"), NULL, 0);
// We used a basic whitening technique that takes the first byte of a new random value and builds up a 32-byte random value
// This 32-byte random value is then hashed (SHA256) to produce the resulting nonce
_signing_sha256.init();
for (int i = 0; i < 32; i++) {
_signing_sha256.write(random(256));
}
memcpy(_signing_current_nonce, _signing_sha256.result(), MAX_PAYLOAD);
DEBUG_SIGNING_PRINTBUF(F("SHA256: "), _signing_current_nonce, 32);
// We set the part of the 32-byte nonce that does not fit into a message to 0xAA
memset(&_signing_current_nonce[MAX_PAYLOAD], 0xAA, sizeof(_signing_current_nonce)-MAX_PAYLOAD);
// Transfer the first part of the nonce to the message
msg.set(_signing_current_nonce, MAX_PAYLOAD);
_signing_verification_ongoing = true;
_signing_timestamp = millis(); // Set timestamp to determine when to purge nonce
// Be a little fancy to handle turnover (prolong the time allowed to timeout after turnover)
// Note that if message is "too" quick, and arrives before turnover, it will be rejected
// but this is consider such a rare case that it is accepted and rejects are 'safe'
if (_signing_timestamp + MY_VERIFICATION_TIMEOUT_MS < millis()) _signing_timestamp = 0;
return true;
}
bool signerAtsha204SoftVerifyMsg(MyMessage &msg) {
if (!_signing_verification_ongoing) {
DEBUG_SIGNING_PRINTBUF(F("No active verification session"), NULL, 0);
return false;
} else {
// Make sure we have not expired
if (!signerCheckTimer()) {
return false;
}
_signing_verification_ongoing = false;
if (msg.data[mGetLength(msg)] != SIGNING_IDENTIFIER) {
DEBUG_SIGNING_PRINTBUF(F("Incorrect signing identifier"), NULL, 0);
return false;
}
// Get signature of message
DEBUG_SIGNING_PRINTBUF(F("Signature in message: "), (uint8_t*)&msg.data[mGetLength(msg)], MAX_PAYLOAD-mGetLength(msg));
signerCalculateSignature(msg);
#ifdef MY_SIGNING_NODE_WHITELISTING
// Look up the senders nodeId in our whitelist and salt the signature with that data
size_t j;
for (j=0; j < NUM_OF(_signing_whitelist); j++) {
if (_signing_whitelist[j].nodeId == msg.sender) {
DEBUG_SIGNING_PRINTBUF(F("Sender found in whitelist"), NULL, 0);
_signing_sha256.init();
for (int i=0; i<32; i++) _signing_sha256.write(_signing_hmac[i]);
_signing_sha256.write(msg.sender);
for (int i=0; i<SHA204_SERIAL_SZ; i++) _signing_sha256.write(_signing_whitelist[j].serial[i]);
memcpy(_signing_hmac, _signing_sha256.result(), 32);
DEBUG_SIGNING_PRINTBUF(F("SHA256: "), _signing_hmac, 32);
break;
}
}
if (j == NUM_OF(_signing_whitelist)) {
DEBUG_SIGNING_PRINTBUF(F("Sender not found in whitelist, message rejected!"), NULL, 0);
return false;
}
#endif
// Overwrite the first byte in the signature with the signing identifier
_signing_hmac[0] = SIGNING_IDENTIFIER;
// Compare the caluclated signature with the provided signature
if (memcmp(&msg.data[mGetLength(msg)], _signing_hmac, MAX_PAYLOAD-mGetLength(msg))) {
DEBUG_SIGNING_PRINTBUF(F("Signature bad: "), _signing_hmac, MAX_PAYLOAD-mGetLength(msg));
#ifdef MY_SIGNING_NODE_WHITELISTING
DEBUG_SIGNING_PRINTBUF(F("Is the sender whitelisted and serial correct?"), NULL, 0);
#endif
return false;
} else {
DEBUG_SIGNING_PRINTBUF(F("Signature OK"), NULL, 0);
return true;
}
}
}
void setup()
{
printf("Test: FIPS 180-2 B.1\n");
printf("Expect:ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad\n");
printf("Result:");
Sha256Class sha;
sha.init();
uint32_t value = 0x1010101;
sha.write('a');
sha.write('b');
sha.write('c');
uint8_t *ans = sha.result();
printHash(ans);
printf("\n");
}
void igc_writeline(char * line, bool sign = true)
{
uint8_t l = strlen(line);
uint16_t wl;
// DEBUG("IGC:%s\n", line);
strcpy_P(line + l, PSTR("\r\n"));
l += 2;
assert(f_write(&log_file, line, l, &wl) == FR_OK);
assert(wl == l);
assert(f_sync(&log_file) == FR_OK);
#ifndef IGC_NO_PRIVATE_KEY
if (sign)
for (uint8_t i = 0; i < l; i++)
sha256.write(line[i]);
#endif
}
uint8_t igc_start(char * path)
{
char filename[128];
uint8_t sec;
uint8_t min;
uint8_t hour;
uint8_t day;
uint8_t wday;
uint8_t month;
uint16_t year;
char line[79];
char id[32];
sha256.init();
IGC_PRIVATE_KEY_ADD;
datetime_from_epoch(time_get_utc(), &sec, &min, &hour, &day, &wday, &month, &year);
//XXX
#define device_uid "DRP"
sprintf_P(filename, PSTR("%sIGC"), path);
DEBUG("IGC filename %s\n", filename);
uint8_t res = f_open(&log_file, filename, FA_WRITE | FA_CREATE_ALWAYS);
assert(res == FR_OK);
DEBUG("f_open res = %02X\n", res);
//cannot create file
if (res != FR_OK)
return false;
//A record
GetID_str(id);
sprintf_P(line, PSTR("A%S%s:%s"), LOG_MID_P, device_uid, id);
igc_writeline(line);
//H records
//H F DTE
sprintf_P(line, PSTR("HFDTE%02u%02u%02u"), day, month, year % 100);
igc_writeline(line);
// //H F DTE
// sprintf_P(line, PSTR("HFDTEDATE:%02u%02u%02u,%02u"), day, month, year % 100, logger_flight_number);
// igc_writeline(line);
//H F PLT PILOT IN CHARGE
sprintf_P(line, PSTR("HFPLTPILOTINCHARGE:%s"), config.logger.pilot);
igc_writeline(line);
//H F CM2 CREW 2
sprintf_P(line, PSTR("HFCM2CREW2:NIL"));
igc_writeline(line);
//H F GTY GLIDER TYPE
sprintf_P(line, PSTR("HFGTYGLIDERTYPE:%s"), config.logger.glider_type);
igc_writeline(line);
//H F GID GLIDER ID
sprintf_P(line, PSTR("HFGIDGLIDERID:%s"), config.logger.glider_id);
igc_writeline(line);
//H F DTM GPS DATUM
sprintf_P(line, PSTR("HFDTMGPSDATUM:WGS84"));
igc_writeline(line);
//H F RFW FIRMWARE VERSION
sprintf_P(line, PSTR("HFRFWFIRMWAREVERSION:build %d"), BUILD_NUMBER);
igc_writeline(line);
//H F RHW HARDWARE VERSION
sprintf_P(line, PSTR("HFRHWHARDWAREVERSION:drop_%d"), (hw_revision == HW_REW_1504) ? 1504 : 1506);
igc_writeline(line);
//H F FTY FR TYPE
sprintf_P(line, PSTR("HFFTYFRTYPE:SkyBean,SkyDrop"));
igc_writeline(line);
//H F GPS RECEIVER
sprintf_P(line, PSTR("HFGPSRECEIVER:Quectel,L80,22cm,18000m"));
igc_writeline(line);
//H F PRS PRESS ALT SENSOR
sprintf_P(line, PSTR("HFPRSPRESSALTSENSOR:Measurement specialties,MS5611,25907m"));
igc_writeline(line);
//H F ALG ALT GPS
sprintf_P(line, PSTR("HFALGALTGPS:GEO"));
igc_writeline(line);
//H F ALP
sprintf_P(line, PSTR("HFALPALTPRESSURE:ISA"));
igc_writeline(line);
//H F TZN
sprintf_P(line, PSTR("HFTZNTIMEZONE:%+0.1f"), config.system.time_zone / 2.0);
igc_writeline(line);
#ifdef IGC_NO_PRIVATE_KEY
//Developer note: we can't publish the private key for signing the IGC file
//H F FRS
sprintf_P(line, PSTR("HFFRSSECSUSPECTUSEVALIPROG:This file is not valid. Private key not available!"));
igc_writeline(line);
#endif
//dump the cache
// DEBUG("IGC dump len %d\n", igc_pre_start_len);
for (uint8_t i = igc_pre_start_len; i > 0; i--)
{
int8_t index = igc_pre_start_index - i;
if (index < 0)
index += IGC_PRE_START_BUFFER;
// DEBUG("IGC dump %d\n", index);
igc_pre_fix * pfix = &igc_pre_start_cache[index];
int16_t galt = pfix->galt;
char c = 'A';
if (galt == 0x7FFF)
{
galt = 0;
c = 'V';
}
sprintf_P(line, PSTR("B%02d%02d%02d%s%s%c%05d%05d"), pfix->hour, pfix->min, pfix->sec, pfix->cache_igc_latitude, pfix->cache_igc_longtitude, c, pfix->balt, galt);
igc_writeline(line);
}
// igc_comment("End of cache");
igc_write_grecord();
return (fc.gps_data.valid) ? LOGGER_ACTIVE : LOGGER_WAIT_FOR_GPS;
}
// Helper to calculate signature of msg (returned in hmac)
static void signerCalculateSignature(MyMessage &msg) {
memset(_signing_temp_message, 0, 32);
memcpy(_signing_temp_message, (uint8_t*)&msg.data[1-HEADER_SIZE], MAX_MESSAGE_LENGTH-1-(MAX_PAYLOAD-mGetLength(msg)));
DEBUG_SIGNING_PRINTBUF(F("Message to process: "), (uint8_t*)&msg.data[1-HEADER_SIZE], MAX_MESSAGE_LENGTH-1-(MAX_PAYLOAD-mGetLength(msg)));
DEBUG_SIGNING_PRINTBUF(F("Current nonce: "), _signing_current_nonce, 32);
// ATSHA204 calculates the HMAC with a PSK and a SHA256 digest of the following data:
// 32 bytes zeroes
// 32 bytes digest,
// 1 byte OPCODE (0x11)
// 1 byte Mode (0x04)
// 2 bytes SlotID (0x0000)
// 11 bytes zeroes
// SN[8] (0xEE)
// 4 bytes zeroes
// SN[0:1] (0x0123)
// 2 bytes zeroes
// The digest is calculated as a SHA256 digest of the following:
// 32 bytes message
// 1 byte OPCODE (0x15)
// 1 byte param1 (0x02)
// 2 bytes param2 (0x0800)
// SN[8] (0xEE)
// SN[0:1] (0x0123)
// 25 bytes zeroes
// 32 bytes nonce
// Calculate message digest first
_signing_sha256.init();
for (int i=0; i<32; i++) _signing_sha256.write(_signing_temp_message[i]);
_signing_sha256.write(0x15); // OPCODE
_signing_sha256.write(0x02); // param1
_signing_sha256.write(0x08); // param2(1)
_signing_sha256.write(0x00); // param2(2)
_signing_sha256.write(0xEE); // SN[8]
_signing_sha256.write(0x01); // SN[0]
_signing_sha256.write(0x23); // SN[1]
for (int i=0; i<25; i++) _signing_sha256.write(0x00);
for (int i=0; i<32; i++) _signing_sha256.write(_signing_current_nonce[i]);
// Purge nonce when used
memset(_signing_current_nonce, 0xAA, 32);
memcpy(_signing_temp_message, _signing_sha256.result(), 32);
// Feed "message" to HMAC calculator
_signing_sha256.initHmac(_signing_hmac_key,32); // Set the key to use
for (int i=0; i<32; i++) _signing_sha256.write(0x00); // 32 bytes zeroes
for (int i=0; i<32; i++) _signing_sha256.write(_signing_temp_message[i]); // 32 bytes digest
_signing_sha256.write(0x11); // OPCODE
_signing_sha256.write(0x04); // Mode
_signing_sha256.write(0x00); // SlotID(1)
_signing_sha256.write(0x00); // SlotID(2)
for (int i=0; i<11; i++) _signing_sha256.write(0x00); // 11 bytes zeroes
_signing_sha256.write(0xEE); // SN[8]
for (int i=0; i<4; i++) _signing_sha256.write(0x00); // 4 bytes zeroes
_signing_sha256.write(0x01); // SN[0]
_signing_sha256.write(0x23); // SN[1]
for (int i=0; i<2; i++) _signing_sha256.write(0x00); // 2 bytes zeroes
memcpy(_signing_hmac, _signing_sha256.resultHmac(), 32);
DEBUG_SIGNING_PRINTBUF(F("HMAC: "), _signing_hmac, 32);
}