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llsec: Allow for sharing CCM*

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This commit is contained in:
kkrentz 2014-04-21 03:33:34 -07:00
parent 13d9510715
commit d161ffcb64
2 changed files with 275 additions and 0 deletions
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190
core/net/llsec/ccm.c Normal file
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/**
* \addtogroup llsec802154
* @{
*/
/*
* Copyright (c) 2013, Hasso-Plattner-Institut.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
*/
/**
* \file
* AES_128-based CCM* implementation.
* \author
* Konrad Krentz <konrad.krentz@gmail.com>
*/
#include "net/llsec/ccm.h"
#include "net/llsec/llsec802154.h"
#include "net/packetbuf.h"
#include "lib/aes-128.h"
#include <string.h>
/*---------------------------------------------------------------------------*/
static void
set_nonce(uint8_t *nonce,
uint8_t flags,
const uint8_t *extended_source_address,
uint8_t counter)
{
/* 1 byte|| 8 bytes || 4 bytes || 1 byte || 2 bytes */
/* flags || extended_source_address || frame_counter || sec_lvl || counter */
nonce[0] = flags;
memcpy(nonce + 1, extended_source_address, 8);
nonce[9] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3) >> 8;
nonce[10] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_2_3) & 0xff;
nonce[11] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1) >> 8;
nonce[12] = packetbuf_attr(PACKETBUF_ATTR_FRAME_COUNTER_BYTES_0_1) & 0xff;
nonce[13] = packetbuf_attr(PACKETBUF_ATTR_SECURITY_LEVEL);
nonce[14] = 0;
nonce[15] = counter;
}
/*---------------------------------------------------------------------------*/
/* XORs the block m[pos] ... m[pos + 15] with K_{counter} */
static void
ctr_step(const uint8_t *extended_source_address,
uint8_t pos,
uint8_t *m_and_result,
uint8_t m_len,
uint8_t counter)
{
uint8_t a[AES_128_BLOCK_SIZE];
uint8_t i;
set_nonce(a, CCM_ENCRYPTION_FLAGS, extended_source_address, counter);
AES_128.encrypt(a);
for(i = 0; (pos + i < m_len) && (i < AES_128_BLOCK_SIZE); i++) {
m_and_result[pos + i] ^= a[i];
}
}
/*---------------------------------------------------------------------------*/
static void
mic(const uint8_t *extended_source_address,
uint8_t *result,
uint8_t mic_len)
{
uint8_t x[AES_128_BLOCK_SIZE];
uint8_t pos;
uint8_t i;
uint8_t a_len;
uint8_t *a;
#if LLSEC802154_USES_ENCRYPTION
uint8_t shall_encrypt;
uint8_t m_len;
uint8_t *m;
shall_encrypt = packetbuf_attr(PACKETBUF_ATTR_SECURITY_LEVEL) & (1 << 2);
if(shall_encrypt) {
a_len = packetbuf_hdrlen();
m_len = packetbuf_datalen();
} else {
a_len = packetbuf_totlen();
m_len = 0;
}
set_nonce(x,
CCM_AUTH_FLAGS(a_len, mic_len),
extended_source_address,
m_len);
#else /* LLSEC802154_USES_ENCRYPTION */
a_len = packetbuf_totlen();
set_nonce(x,
CCM_AUTH_FLAGS(a_len, mic_len),
extended_source_address,
0);
#endif /* LLSEC802154_USES_ENCRYPTION */
AES_128.encrypt(x);
a = packetbuf_hdrptr();
if(a_len) {
x[1] = x[1] ^ a_len;
for(i = 2; (i - 2 < a_len) && (i < AES_128_BLOCK_SIZE); i++) {
x[i] ^= a[i - 2];
}
AES_128.encrypt(x);
pos = 14;
while(pos < a_len) {
for(i = 0; (pos + i < a_len) && (i < AES_128_BLOCK_SIZE); i++) {
x[i] ^= a[pos + i];
}
pos += AES_128_BLOCK_SIZE;
AES_128.encrypt(x);
}
}
#if LLSEC802154_USES_ENCRYPTION
if(shall_encrypt) {
m = a + a_len;
pos = 0;
while(pos < m_len) {
for(i = 0; (pos + i < m_len) && (i < AES_128_BLOCK_SIZE); i++) {
x[i] ^= m[pos + i];
}
pos += AES_128_BLOCK_SIZE;
AES_128.encrypt(x);
}
}
#endif /* LLSEC802154_USES_ENCRYPTION */
ctr_step(extended_source_address, 0, x, AES_128_BLOCK_SIZE, 0);
memcpy(result, x, mic_len);
}
/*---------------------------------------------------------------------------*/
static void
ctr(const uint8_t *extended_source_address)
{
uint8_t m_len;
uint8_t *m;
uint8_t pos;
uint8_t counter;
m_len = packetbuf_datalen();
m = (uint8_t *) packetbuf_dataptr();
pos = 0;
counter = 1;
while(pos < m_len) {
ctr_step(extended_source_address, pos, m, m_len, counter++);
pos += AES_128_BLOCK_SIZE;
}
}
/*---------------------------------------------------------------------------*/
const struct ccm_driver ccm_driver = {
mic,
ctr
};
/*---------------------------------------------------------------------------*/
/** @} */

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core/net/llsec/ccm.h Normal file
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/**
* \addtogroup llsec802154
* @{
*/
/*
* Copyright (c) 2013, Hasso-Plattner-Institut.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Contiki operating system.
*
*/
/**
* \file
* CCM* header file.
* \author
* Konrad Krentz <konrad.krentz@gmail.com>
*/
#ifndef CCM_H_
#define CCM_H_
#include "contiki.h"
#include "net/mac/frame802154.h"
/* see RFC 3610 */
#define CCM_AUTH_FLAGS(Adata, M) ((Adata ? (1 << 6) : 0) | (((M - 2) >> 1) << 3) | 1)
#define CCM_ENCRYPTION_FLAGS 1
#ifdef CCM_CONF
#define CCM CCM_CONF
#else /* CCM_CONF */
#define CCM ccm_driver
#endif /* CCM_CONF */
/**
* Structure of CCM drivers.
*/
struct ccm_driver {
/**
* \brief Generates a MIC over the frame in the packetbuf.
* \param result The generated MIC will be put here
* \param mic_len <= 16; set to LLSEC802154_MIC_LENGTH to be compliant
*/
void (* mic)(const uint8_t *extended_source_address,
uint8_t *result,
uint8_t mic_len);
/**
* \brief XORs the frame in the packetbuf with the key stream.
*/
void (* ctr)(const uint8_t *extended_source_address);
};
extern const struct ccm_driver CCM;
#endif /* CCM_H_ */
/** @} */