370 lines
11 KiB
C
370 lines
11 KiB
C
/******************************************************************************
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*
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* Copyright (C) 2008-2012 Broadcom Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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******************************************************************************/
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/******************************************************************************
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*
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* This file contains the implementation of the AES128 CMAC algorithm.
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*
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******************************************************************************/
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#include "bt_target.h"
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#include "allocator.h"
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#if SMP_INCLUDED == TRUE
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// #include <stdio.h>
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#include <string.h>
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#include "btm_ble_api.h"
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#include "smp_int.h"
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#include "hcimsgs.h"
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typedef struct {
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UINT8 *text;
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UINT16 len;
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UINT16 round;
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} tCMAC_CB;
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tCMAC_CB cmac_cb;
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/* Rb for AES-128 as block cipher, LSB as [0] */
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BT_OCTET16 const_Rb = {
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0x87, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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void print128(BT_OCTET16 x, const UINT8 *key_name)
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{
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#if SMP_DEBUG == TRUE && SMP_DEBUG_VERBOSE == TRUE
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UINT8 *p = (UINT8 *)x;
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UINT8 i;
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SMP_TRACE_WARNING("%s(MSB ~ LSB) = ", key_name);
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for (i = 0; i < 4; i ++) {
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SMP_TRACE_WARNING("%02x %02x %02x %02x",
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p[BT_OCTET16_LEN - i * 4 - 1], p[BT_OCTET16_LEN - i * 4 - 2],
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p[BT_OCTET16_LEN - i * 4 - 3], p[BT_OCTET16_LEN - i * 4 - 4]);
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}
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#endif
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}
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/*******************************************************************************
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**
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** Function padding
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**
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** Description utility function to padding the given text to be a 128 bits
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** data. The parameter dest is input and output parameter, it
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** must point to a BT_OCTET16_LEN memory space; where include
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** length bytes valid data.
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**
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** Returns void
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**
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*******************************************************************************/
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static void padding ( BT_OCTET16 dest, UINT8 length )
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{
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UINT8 i, *p = dest;
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/* original last block */
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for ( i = length ; i < BT_OCTET16_LEN; i++ ) {
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p[BT_OCTET16_LEN - i - 1] = ( i == length ) ? 0x80 : 0;
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}
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}
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/*******************************************************************************
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**
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** Function leftshift_onebit
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**
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** Description utility function to left shift one bit for a 128 bits value.
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**
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** Returns void
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**
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*******************************************************************************/
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static void leftshift_onebit(UINT8 *input, UINT8 *output)
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{
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UINT8 i, overflow = 0 , next_overflow = 0;
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SMP_TRACE_EVENT ("leftshift_onebit ");
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/* input[0] is LSB */
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for ( i = 0; i < BT_OCTET16_LEN ; i ++ ) {
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next_overflow = (input[i] & 0x80) ? 1 : 0;
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output[i] = (input[i] << 1) | overflow;
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overflow = next_overflow;
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}
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return;
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}
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/*******************************************************************************
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**
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** Function cmac_aes_cleanup
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**
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** Description clean up function for AES_CMAC algorithm.
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**
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** Returns void
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**
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*******************************************************************************/
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static void cmac_aes_cleanup(void)
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{
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if (cmac_cb.text != NULL) {
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osi_free(cmac_cb.text);
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}
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memset(&cmac_cb, 0, sizeof(tCMAC_CB));
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}
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/*******************************************************************************
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**
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** Function cmac_aes_k_calculate
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**
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** Description This function is the calculation of block cipher using AES-128.
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**
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** Returns void
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**
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*******************************************************************************/
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static BOOLEAN cmac_aes_k_calculate(BT_OCTET16 key, UINT8 *p_signature, UINT16 tlen)
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{
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tSMP_ENC output;
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UINT8 i = 1, err = 0;
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UINT8 x[16] = {0};
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UINT8 *p_mac;
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SMP_TRACE_EVENT ("cmac_aes_k_calculate ");
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while (i <= cmac_cb.round) {
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smp_xor_128(&cmac_cb.text[(cmac_cb.round - i)*BT_OCTET16_LEN], x); /* Mi' := Mi (+) X */
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if (!SMP_Encrypt(key, BT_OCTET16_LEN, &cmac_cb.text[(cmac_cb.round - i)*BT_OCTET16_LEN], BT_OCTET16_LEN, &output)) {
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err = 1;
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break;
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}
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memcpy(x, output.param_buf, BT_OCTET16_LEN);
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i ++;
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}
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if (!err) {
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p_mac = output.param_buf + (BT_OCTET16_LEN - tlen);
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memcpy(p_signature, p_mac, tlen);
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SMP_TRACE_DEBUG("tlen = %d p_mac = %p", tlen, p_mac);
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SMP_TRACE_DEBUG("p_mac[0] = 0x%02x p_mac[1] = 0x%02x p_mac[2] = 0x%02x p_mac[3] = 0x%02x",
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*p_mac, *(p_mac + 1), *(p_mac + 2), *(p_mac + 3));
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SMP_TRACE_DEBUG("p_mac[4] = 0x%02x p_mac[5] = 0x%02x p_mac[6] = 0x%02x p_mac[7] = 0x%02x",
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*(p_mac + 4), *(p_mac + 5), *(p_mac + 6), *(p_mac + 7));
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return TRUE;
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} else {
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return FALSE;
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}
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}
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/*******************************************************************************
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**
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** Function cmac_prepare_last_block
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**
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** Description This function proceeed to prepare the last block of message
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** Mn depending on the size of the message.
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**
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** Returns void
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**
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*******************************************************************************/
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static void cmac_prepare_last_block (BT_OCTET16 k1, BT_OCTET16 k2)
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{
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// UINT8 x[16] = {0};
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BOOLEAN flag;
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SMP_TRACE_EVENT ("cmac_prepare_last_block ");
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/* last block is a complete block set flag to 1 */
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flag = ((cmac_cb.len % BT_OCTET16_LEN) == 0 && cmac_cb.len != 0) ? TRUE : FALSE;
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SMP_TRACE_DEBUG("flag = %d round = %d", flag, cmac_cb.round);
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if ( flag ) {
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/* last block is complete block */
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smp_xor_128(&cmac_cb.text[0], k1);
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} else { /* padding then xor with k2 */
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padding(&cmac_cb.text[0], (UINT8)(cmac_cb.len % 16));
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smp_xor_128(&cmac_cb.text[0], k2);
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}
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}
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/*******************************************************************************
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**
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** Function cmac_subkey_cont
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**
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** Description This is the callback function when CIPHk(0[128]) is completed.
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**
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** Returns void
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**
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*******************************************************************************/
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static void cmac_subkey_cont(tSMP_ENC *p)
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{
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UINT8 k1[BT_OCTET16_LEN], k2[BT_OCTET16_LEN];
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UINT8 *pp = p->param_buf;
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SMP_TRACE_EVENT ("cmac_subkey_cont ");
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print128(pp, (const UINT8 *)"K1 before shift");
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/* If MSB(L) = 0, then K1 = L << 1 */
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if ( (pp[BT_OCTET16_LEN - 1] & 0x80) != 0 ) {
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/* Else K1 = ( L << 1 ) (+) Rb */
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leftshift_onebit(pp, k1);
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smp_xor_128(k1, const_Rb);
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} else {
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leftshift_onebit(pp, k1);
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}
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if ( (k1[BT_OCTET16_LEN - 1] & 0x80) != 0 ) {
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/* K2 = (K1 << 1) (+) Rb */
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leftshift_onebit(k1, k2);
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smp_xor_128(k2, const_Rb);
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} else {
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/* If MSB(K1) = 0, then K2 = K1 << 1 */
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leftshift_onebit(k1, k2);
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}
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print128(k1, (const UINT8 *)"K1");
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print128(k2, (const UINT8 *)"K2");
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cmac_prepare_last_block (k1, k2);
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}
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/*******************************************************************************
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**
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** Function cmac_generate_subkey
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**
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** Description This is the function to generate the two subkeys.
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**
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** Parameters key - CMAC key, expect SRK when used by SMP.
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**
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** Returns void
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**
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*******************************************************************************/
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static BOOLEAN cmac_generate_subkey(BT_OCTET16 key)
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{
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BT_OCTET16 z = {0};
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BOOLEAN ret = TRUE;
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tSMP_ENC output;
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SMP_TRACE_EVENT (" cmac_generate_subkey");
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if (SMP_Encrypt(key, BT_OCTET16_LEN, z, BT_OCTET16_LEN, &output)) {
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cmac_subkey_cont(&output);;
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} else {
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ret = FALSE;
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}
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return ret;
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}
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/*******************************************************************************
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**
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** Function aes_cipher_msg_auth_code
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**
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** Description This is the AES-CMAC Generation Function with tlen implemented.
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**
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** Parameters key - CMAC key in little endian order, expect SRK when used by SMP.
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** input - text to be signed in little endian byte order.
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** length - length of the input in byte.
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** tlen - lenth of mac desired
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** p_signature - data pointer to where signed data to be stored, tlen long.
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**
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** Returns FALSE if out of resources, TRUE in other cases.
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**
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*******************************************************************************/
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BOOLEAN aes_cipher_msg_auth_code(BT_OCTET16 key, UINT8 *input, UINT16 length,
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UINT16 tlen, UINT8 *p_signature)
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{
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UINT16 len, diff;
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UINT16 n = (length + BT_OCTET16_LEN - 1) / BT_OCTET16_LEN; /* n is number of rounds */
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BOOLEAN ret = FALSE;
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SMP_TRACE_EVENT ("%s", __func__);
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if (n == 0) {
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n = 1;
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}
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len = n * BT_OCTET16_LEN;
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SMP_TRACE_DEBUG("AES128_CMAC started, allocate buffer size = %d", len);
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/* allocate a memory space of multiple of 16 bytes to hold text */
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if ((cmac_cb.text = (UINT8 *)osi_malloc(len)) != NULL) {
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cmac_cb.round = n;
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memset(cmac_cb.text, 0, len);
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diff = len - length;
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if (input != NULL && length > 0) {
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memcpy(&cmac_cb.text[diff] , input, (int)length);
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cmac_cb.len = length;
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} else {
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cmac_cb.len = 0;
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}
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/* prepare calculation for subkey s and last block of data */
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if (cmac_generate_subkey(key)) {
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/* start calculation */
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ret = cmac_aes_k_calculate(key, p_signature, tlen);
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}
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/* clean up */
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cmac_aes_cleanup();
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} else {
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ret = FALSE;
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SMP_TRACE_ERROR("No resources");
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}
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return ret;
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}
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#if 0 /* testing code, sample data from spec */
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void test_cmac_cback(UINT8 *p_mac, UINT16 tlen)
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{
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SMP_TRACE_EVENT ("test_cmac_cback ");
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SMP_TRACE_ERROR("test_cmac_cback");
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}
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void test_cmac(void)
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{
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SMP_TRACE_EVENT ("test_cmac ");
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UINT8 M[64] = {
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0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
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0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
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0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
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0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
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0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
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0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
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0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
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0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10
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};
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UINT8 key[16] = {
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0x3c, 0x4f, 0xcf, 0x09, 0x88, 0x15, 0xf7, 0xab,
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0xa6, 0xd2, 0xae, 0x28, 0x16, 0x15, 0x7e, 0x2b
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};
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UINT8 i = 0, tmp;
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UINT16 len;
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len = 64;
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for (i = 0; i < len / 2; i ++) {
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tmp = M[i];
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M[i] = M[len - 1 - i];
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M[len - 1 - i] = tmp;
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}
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memset(&cmac_cb, 0, sizeof(tCMAC_CB));
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SMP_TRACE_WARNING("\n Example 1: len = %d\n", len);
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aes_cipher_msg_auth_code(key, M, len, 128, test_cmac_cback, 0);
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}
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#endif
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#endif
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