222 lines
7.1 KiB
C
222 lines
7.1 KiB
C
/*
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* Copyright (c) 2014, Hasso-Plattner-Institut.
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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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* 802.15.4 security implementation, which uses a network-wide key
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* \author
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* Konrad Krentz <konrad.krentz@gmail.com>
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*/
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/**
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* \addtogroup noncoresec
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* @{
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*/
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#include "net/llsec/noncoresec/noncoresec.h"
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#include "net/llsec/anti-replay.h"
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#include "net/llsec/llsec802154.h"
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#include "net/llsec/ccm-star.h"
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#include "net/mac/frame802154.h"
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#include "net/netstack.h"
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#include "net/packetbuf.h"
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#include "net/nbr-table.h"
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#include "net/linkaddr.h"
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#include "lib/aes-128.h"
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#include <string.h>
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#define WITH_ENCRYPTION (LLSEC802154_SECURITY_LEVEL & (1 << 2))
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#ifdef NONCORESEC_CONF_KEY
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#define NONCORESEC_KEY NONCORESEC_CONF_KEY
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#else /* NONCORESEC_CONF_KEY */
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#define NONCORESEC_KEY { 0x00 , 0x01 , 0x02 , 0x03 , \
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0x04 , 0x05 , 0x06 , 0x07 , \
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0x08 , 0x09 , 0x0A , 0x0B , \
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0x0C , 0x0D , 0x0E , 0x0F }
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#endif /* NONCORESEC_CONF_KEY */
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#define SECURITY_HEADER_LENGTH 5
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#define DEBUG 0
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#if DEBUG
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#include <stdio.h>
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#define PRINTF(...) printf(__VA_ARGS__)
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#else /* DEBUG */
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#define PRINTF(...)
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#endif /* DEBUG */
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/* network-wide CCM* key */
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static uint8_t key[16] = NONCORESEC_KEY;
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NBR_TABLE(struct anti_replay_info, anti_replay_table);
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/*---------------------------------------------------------------------------*/
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static const uint8_t *
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get_extended_address(const linkaddr_t *addr)
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#if LINKADDR_SIZE == 2
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{
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/* workaround for short addresses: derive EUI64 as in RFC 6282 */
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static linkaddr_extended_t template = { { 0x00 , 0x00 , 0x00 ,
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0xFF , 0xFE , 0x00 , 0x00 , 0x00 } };
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template.u16[3] = LLSEC802154_HTONS(addr->u16);
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return template.u8;
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}
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#else /* LINKADDR_SIZE == 2 */
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{
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return addr->u8;
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}
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#endif /* LINKADDR_SIZE == 2 */
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/*---------------------------------------------------------------------------*/
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static void
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send(mac_callback_t sent, void *ptr)
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{
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packetbuf_set_attr(PACKETBUF_ATTR_FRAME_TYPE, FRAME802154_DATAFRAME);
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packetbuf_set_attr(PACKETBUF_ATTR_SECURITY_LEVEL, LLSEC802154_SECURITY_LEVEL);
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anti_replay_set_counter();
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NETSTACK_MAC.send(sent, ptr);
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}
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/*---------------------------------------------------------------------------*/
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static int
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on_frame_created(void)
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{
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uint8_t *dataptr;
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uint8_t data_len;
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dataptr = packetbuf_dataptr();
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data_len = packetbuf_datalen();
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CCM_STAR.mic(get_extended_address(&linkaddr_node_addr), dataptr + data_len, LLSEC802154_MIC_LENGTH);
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#if WITH_ENCRYPTION
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CCM_STAR.ctr(get_extended_address(&linkaddr_node_addr));
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#endif /* WITH_ENCRYPTION */
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packetbuf_set_datalen(data_len + LLSEC802154_MIC_LENGTH);
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return 1;
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}
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/*---------------------------------------------------------------------------*/
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static void
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input(void)
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{
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uint8_t generated_mic[LLSEC802154_MIC_LENGTH];
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uint8_t *received_mic;
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const linkaddr_t *sender;
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struct anti_replay_info* info;
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if(packetbuf_attr(PACKETBUF_ATTR_SECURITY_LEVEL) != LLSEC802154_SECURITY_LEVEL) {
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PRINTF("noncoresec: received frame with wrong security level\n");
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return;
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}
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sender = packetbuf_addr(PACKETBUF_ADDR_SENDER);
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if(linkaddr_cmp(sender, &linkaddr_node_addr)) {
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PRINTF("noncoresec: frame from ourselves\n");
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return;
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}
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packetbuf_set_datalen(packetbuf_datalen() - LLSEC802154_MIC_LENGTH);
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#if WITH_ENCRYPTION
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CCM_STAR.ctr(get_extended_address(sender));
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#endif /* WITH_ENCRYPTION */
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CCM_STAR.mic(get_extended_address(sender), generated_mic, LLSEC802154_MIC_LENGTH);
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received_mic = ((uint8_t *) packetbuf_dataptr()) + packetbuf_datalen();
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if(memcmp(generated_mic, received_mic, LLSEC802154_MIC_LENGTH) != 0) {
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PRINTF("noncoresec: received nonauthentic frame %"PRIu32"\n",
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anti_replay_get_counter());
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return;
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}
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info = nbr_table_get_from_lladdr(anti_replay_table, sender);
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if(!info) {
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info = nbr_table_add_lladdr(anti_replay_table, sender);
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if(!info) {
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PRINTF("noncoresec: could not get nbr_table_item\n");
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return;
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}
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/*
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* Locking avoids replay attacks due to removed neighbor table items.
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* Unfortunately, an attacker can mount a memory-based DoS attack
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* on this by replaying broadcast frames from other network parts.
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* However, this is not an issue as long as the network size does not
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* exceed NBR_TABLE_MAX_NEIGHBORS.
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*
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* To avoid locking, we could swap anti-replay information
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* to external flash. Locking is also unnecessary when using
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* pairwise session keys, as done in coresec.
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*/
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if(!nbr_table_lock(anti_replay_table, info)) {
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nbr_table_remove(anti_replay_table, info);
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PRINTF("noncoresec: could not lock\n");
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return;
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}
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anti_replay_init_info(info);
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} else {
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if(anti_replay_was_replayed(info)) {
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PRINTF("noncoresec: received replayed frame %"PRIu32"\n",
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anti_replay_get_counter());
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return;
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}
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}
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NETSTACK_NETWORK.input();
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}
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/*---------------------------------------------------------------------------*/
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static uint8_t
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get_overhead(void)
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{
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return SECURITY_HEADER_LENGTH + LLSEC802154_MIC_LENGTH;
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}
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/*---------------------------------------------------------------------------*/
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static void
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bootstrap(llsec_on_bootstrapped_t on_bootstrapped)
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{
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AES_128.set_key(key);
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nbr_table_register(anti_replay_table, NULL);
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on_bootstrapped();
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}
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/*---------------------------------------------------------------------------*/
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const struct llsec_driver noncoresec_driver = {
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"noncoresec",
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bootstrap,
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send,
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on_frame_created,
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input,
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get_overhead
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};
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/*---------------------------------------------------------------------------*/
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/** @} */
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