Mavlink 2.0 Authentication supportted yet on PX4?

Topflight · May 15, 2017, 4:41pm

Hi folks,
I was pretty sure that PX4 was updated to support Mavlink 2.0 messages however it doesn’t appear to me that it supports the packet signing yet as ArduPilot does. QGroundControl also doesn’t seem to support the setup and transmittal of secure keys in the manner that MissionPlanner does. Am I mistaken on this? is there a plan to roll that out?
Thanks.

dagar · May 15, 2017, 5:09pm

Yes PX4 is able to switch between Mavlink 1.0 and 2.0, but I don’t see packet signing implemented yet. Are you interested in adding this? I could help point you in the right direction if you aren’t familiar with the code base.

Topflight · May 19, 2017, 11:27am

Definitely interested, just not sure I have the bandwidth at the moment. I assume we would utilize the ArduPilot packet signing code for this? are we sure no one else is already working this? would not want to duplicate effort here.

dagar · May 19, 2017, 12:31pm

The signing is part of mavlink 2, you just need to implement the setup. http://mavlink.org/messages/common#SETUP_SIGNING

github.com

mavlink/c_library_v2/blob/master/mavlink_helpers.h#L64


*/
MAVLINK_HELPER void mavlink_reset_channel_status(uint8_t chan)
{
	mavlink_status_t *status = mavlink_get_channel_status(chan);
	status->parse_state = MAVLINK_PARSE_STATE_IDLE;
}


/**
* @brief create a signature block for a packet
*/
MAVLINK_HELPER uint8_t mavlink_sign_packet(mavlink_signing_t *signing,
					   uint8_t signature[MAVLINK_SIGNATURE_BLOCK_LEN],
					   const uint8_t *header, uint8_t header_len,
					   const uint8_t *packet, uint8_t packet_len,
					   const uint8_t crc[2])
{
	mavlink_sha256_ctx ctx;
	union {
	    uint64_t t64;
	    uint8_t t8[8];
	} tstamp;

github.com

mavlink/c_library_v2/blob/master/mavlink_helpers.h#L110


{
	while (length > 1 && payload[length-1] == 0) {
		length--;
	}
	return length;
}


/**
 * @brief check a signature block for a packet
 */
MAVLINK_HELPER bool mavlink_signature_check(mavlink_signing_t *signing,
					    mavlink_signing_streams_t *signing_streams,
					    const mavlink_message_t *msg)
{
	if (signing == NULL) {
		return true;
	}
        const uint8_t *p = (const uint8_t *)&msg->magic;
	const uint8_t *psig = msg->signature;
        const uint8_t *incoming_signature = psig+7;
	mavlink_sha256_ctx ctx;

@DonLakeFlyer @LorenzMeier Any immediate plans to implement mavlink 2 signing?

DonLakeFlyer · May 22, 2017, 5:01pm

No immediate plans for mav 2 signing.