Added IEEE 802.15.4e TSCH (TimeSlotted Channel Hopping) MAC layer
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Simon Duquennoy
parent
1e0adbbf24
commit
b0f936263e
20 changed files with 5239 additions and 2 deletions
285
core/net/mac/tsch/tsch-security.c
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285
core/net/mac/tsch/tsch-security.c
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/*
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* Copyright (c) 2014, SICS Swedish ICT.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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*/
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/**
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* \file
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* TSCH security
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* \author
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* Simon Duquennoy <simonduq@sics.se>
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*/
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#include "contiki.h"
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#include "net/mac/tsch/tsch.h"
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#include "net/mac/tsch/tsch-packet.h"
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#include "net/mac/tsch/tsch-private.h"
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#include "net/mac/tsch/tsch-schedule.h"
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#include "net/mac/tsch/tsch-security.h"
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#include "net/mac/tsch/tsch-log.h"
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#include "net/mac/frame802154.h"
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#include "net/mac/framer-802154.h"
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#include "net/netstack.h"
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#include "net/packetbuf.h"
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#include "lib/ccm-star.h"
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#include "lib/aes-128.h"
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#include <stdio.h>
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#include <string.h>
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#if TSCH_LOG_LEVEL >= 1
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#define DEBUG DEBUG_PRINT
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#else /* TSCH_LOG_LEVEL */
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#define DEBUG DEBUG_NONE
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#endif /* TSCH_LOG_LEVEL */
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#include "net/ip/uip-debug.h"
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/* The two keys K1 and K2 from 6TiSCH minimal configuration
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* K1: well-known, used for EBs
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* K2: secret, used for data and ACK
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* */
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static aes_key keys[] = {
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TSCH_SECURITY_K1,
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TSCH_SECURITY_K2
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};
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#define N_KEYS (sizeof(keys) / sizeof(aes_key))
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/*---------------------------------------------------------------------------*/
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static void
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aead(const uint8_t *nonce,
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uint8_t *m, uint8_t m_len,
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const uint8_t *a, uint8_t a_len,
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uint8_t *result, uint8_t mic_len,
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int forward)
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{
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if(!forward) {
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/* decrypt */
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CCM_STAR.ctr(m, m_len, nonce);
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}
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CCM_STAR.mic(
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(const uint8_t *)m, m_len,
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nonce,
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a, a_len,
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result,
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mic_len);
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if(forward) {
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/* encrypt */
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CCM_STAR.ctr(m, m_len, nonce);
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}
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}
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/*---------------------------------------------------------------------------*/
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static void
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tsch_security_init_nonce(uint8_t *nonce,
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const linkaddr_t *sender, struct asn_t *asn)
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{
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memcpy(nonce, sender, 8);
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nonce[8] = asn->ms1b;
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nonce[9] = (asn->ls4b >> 24) & 0xff;
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nonce[10] = (asn->ls4b >> 16) & 0xff;
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nonce[11] = (asn->ls4b >> 8) & 0xff;
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nonce[12] = (asn->ls4b) & 0xff;
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}
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/*---------------------------------------------------------------------------*/
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static int
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tsch_security_check_level(const frame802154_t *frame)
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{
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uint8_t required_security_level;
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uint8_t required_key_index;
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/* Sanity check */
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if(frame == NULL) {
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return 0;
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}
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/* Non-secured frame, ok iff we are not in a secured PAN
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* (i.e. scanning or associated to a non-secured PAN) */
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if(frame->fcf.security_enabled == 0) {
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return !(tsch_is_associated == 1 && tsch_is_pan_secured == 1);
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}
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/* The frame is secured, that we are not in an unsecured PAN */
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if(tsch_is_associated == 1 && tsch_is_pan_secured == 0) {
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return 0;
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}
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/* The frame is secured, check its security level */
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switch(frame->fcf.frame_type) {
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case FRAME802154_BEACONFRAME:
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required_security_level = TSCH_SECURITY_KEY_SEC_LEVEL_EB;
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required_key_index = TSCH_SECURITY_KEY_INDEX_EB;
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break;
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case FRAME802154_ACKFRAME:
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required_security_level = TSCH_SECURITY_KEY_SEC_LEVEL_ACK;
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required_key_index = TSCH_SECURITY_KEY_INDEX_ACK;
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break;
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default:
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required_security_level = TSCH_SECURITY_KEY_SEC_LEVEL_OTHER;
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required_key_index = TSCH_SECURITY_KEY_INDEX_OTHER;
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break;
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}
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return frame->aux_hdr.security_control.security_level == required_security_level
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&& frame->aux_hdr.key_index == required_key_index;
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}
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/*---------------------------------------------------------------------------*/
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int
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tsch_security_mic_len(const frame802154_t *frame)
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{
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if(frame != NULL && frame->fcf.security_enabled) {
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return 2 << (frame->aux_hdr.security_control.security_level & 0x03);
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} else {
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return 0;
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}
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}
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/*---------------------------------------------------------------------------*/
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int
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tsch_security_secure_frame(uint8_t *hdr, uint8_t *outbuf,
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int hdrlen, int datalen, struct asn_t *asn)
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{
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frame802154_t frame;
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uint8_t key_index = 0;
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uint8_t security_level = 0;
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uint8_t with_encryption;
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uint8_t mic_len;
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uint8_t nonce[16];
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uint8_t a_len;
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uint8_t m_len;
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if(hdr == NULL || outbuf == NULL || hdrlen < 0 || datalen < 0) {
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return 0;
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}
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/* Parse the frame header to extract security settings */
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if(frame802154_parse(hdr, hdrlen + datalen, &frame) < 3) {
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return 0;
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}
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if(!frame.fcf.security_enabled) {
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/* Security is not enabled for this frame, we're done */
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return 1;
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}
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/* Read security key index */
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key_index = frame.aux_hdr.key_index;
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security_level = frame.aux_hdr.security_control.security_level;
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with_encryption = (security_level & 0x4) ? 1 : 0;
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mic_len = tsch_security_mic_len(&frame);
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if(key_index == 0 || key_index > N_KEYS) {
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return 0;
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}
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tsch_security_init_nonce(nonce, &linkaddr_node_addr, asn);
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if(with_encryption) {
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a_len = hdrlen;
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m_len = datalen;
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} else {
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a_len = hdrlen + datalen;
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m_len = 0;
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}
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/* Copy source data to output */
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if(hdr != outbuf) {
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memcpy(outbuf, hdr, a_len + m_len);
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}
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CCM_STAR.set_key(keys[key_index - 1]);
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aead(nonce,
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outbuf + a_len, m_len,
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outbuf, a_len,
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outbuf + hdrlen + datalen, mic_len, 1
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);
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return mic_len;
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}
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/*---------------------------------------------------------------------------*/
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int
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tsch_security_parse_frame(const uint8_t *hdr, int hdrlen, int datalen,
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const frame802154_t *frame, const linkaddr_t *sender, struct asn_t *asn)
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{
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uint8_t generated_mic[16];
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uint8_t key_index = 0;
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uint8_t security_level = 0;
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uint8_t with_encryption;
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uint8_t mic_len;
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uint8_t nonce[16];
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uint8_t a_len;
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uint8_t m_len;
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if(frame == NULL || hdr == NULL || hdrlen < 0 || datalen < 0) {
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return 0;
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}
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if(!tsch_security_check_level(frame)) {
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/* Wrong security level */
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return 0;
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}
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/* No security: nothing more to check */
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if(!frame->fcf.security_enabled) {
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return 1;
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}
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key_index = frame->aux_hdr.key_index;
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security_level = frame->aux_hdr.security_control.security_level;
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with_encryption = (security_level & 0x4) ? 1 : 0;
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mic_len = tsch_security_mic_len(frame);
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/* Check if key_index is in supported range */
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if(key_index == 0 || key_index > N_KEYS) {
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return 0;
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}
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tsch_security_init_nonce(nonce, sender, asn);
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if(with_encryption) {
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a_len = hdrlen;
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m_len = datalen;
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} else {
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a_len = hdrlen + datalen;
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m_len = 0;
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}
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CCM_STAR.set_key(keys[key_index - 1]);
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aead(nonce,
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(uint8_t *)hdr + a_len, m_len,
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(uint8_t *)hdr, a_len,
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generated_mic, mic_len, 0
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);
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if(mic_len > 0 && memcmp(generated_mic, hdr + hdrlen + datalen, mic_len) != 0) {
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return 0;
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} else {
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return 1;
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}
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}
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