/*
* Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The OpenAirInterface Software Alliance licenses this file to You under
* the OAI Public License, Version 1.1 (the "License"); you may not use this file
* except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.openairinterface.org/?page_id=698
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*-------------------------------------------------------------------------------
* For more information about the OpenAirInterface (OAI) Software Alliance:
* contact@openairinterface.org
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <nettle/nettle-meta.h>
#include <nettle/aes.h>
#include <nettle/ctr.h>
#include "common/utils/LOG/log.h"
#include "assertions.h"
#include "osa_defs.h"
#include "osa_snow3g.h"
#include "osa_internal.h"
int stream_encrypt_eea0(stream_cipher_t *stream_cipher, uint8_t **out)
{
uint8_t *data = NULL;
uint32_t byte_length;
DevAssert(stream_cipher != NULL);
DevAssert(out != NULL);
LOG_D(OSA, "Entering stream_encrypt_eea0, bits length %u, bearer %u, "
"count %u, direction %s\n", stream_cipher->blength,
stream_cipher->bearer, stream_cipher->count, stream_cipher->direction == SECU_DIRECTION_DOWNLINK ?
"Downlink" : "Uplink");
byte_length = (stream_cipher->blength + 7) >> 3;
if (*out == NULL) {
/* User did not provide output buffer */
data = malloc(byte_length);
*out = data;
} else {
data = *out;
}
memcpy (data, stream_cipher->message, byte_length);
return 0;
}
int stream_encrypt_eea1(stream_cipher_t *stream_cipher, uint8_t **out)
{
osa_snow_3g_context_t snow_3g_context;
int n ;
int i = 0;
uint32_t zero_bit = 0;
uint32_t *KS;
uint32_t K[4],IV[4];
DevAssert(stream_cipher != NULL);
DevAssert(stream_cipher->key != NULL);
DevAssert(stream_cipher->key_length == 16);
DevAssert(out != NULL);
n = ( stream_cipher->blength + 31 ) / 32;
zero_bit = stream_cipher->blength & 0x7;
memset(&snow_3g_context, 0, sizeof(snow_3g_context));
/*Initialisation*/
/* Load the confidentiality key for SNOW 3G initialization as in section
3.4. */
memcpy(K+3,stream_cipher->key+0,4); /*K[3] = key[0]; we assume
K[3]=key[0]||key[1]||...||key[31] , with key[0] the
* most important bit of key*/
memcpy(K+2,stream_cipher->key+4,4); /*K[2] = key[1];*/
memcpy(K+1,stream_cipher->key+8,4); /*K[1] = key[2];*/
memcpy(K+0,stream_cipher->key+12,4); /*K[0] = key[3]; we assume
K[0]=key[96]||key[97]||...||key[127] , with key[127] the
* least important bit of key*/
K[3] = hton_int32(K[3]);
K[2] = hton_int32(K[2]);
K[1] = hton_int32(K[1]);
K[0] = hton_int32(K[0]);
/* Prepare the initialization vector (IV) for SNOW 3G initialization as in
section 3.4. */
IV[3] = stream_cipher->count;
IV[2] = ((((uint32_t)stream_cipher->bearer) << 3) | ((((uint32_t)stream_cipher->direction) & 0x1) << 2)) << 24;
IV[1] = IV[3];
IV[0] = IV[2];
/* Run SNOW 3G algorithm to generate sequence of key stream bits KS*/
osa_snow3g_initialize(K, IV, &snow_3g_context);
KS = (uint32_t *)malloc(4*n);
osa_snow3g_generate_key_stream(n,(uint32_t*)KS, &snow_3g_context);
if (zero_bit > 0) {
KS[n - 1] = KS[n - 1] & (uint32_t)(0xFFFFFFFF << (8 - zero_bit));
}
for (i=0; i<n; i++) {
KS[i] = hton_int32(KS[i]);
}
/* Exclusive-OR the input data with keystream to generate the output bit
stream */
for (i=0; i<n*4; i++) {
stream_cipher->message[i] ^= *(((uint8_t*)KS)+i);
}
if (zero_bit > 0) {
int ceil_index = (stream_cipher->blength+7) >> 3;
stream_cipher->message[ceil_index - 1] = stream_cipher->message[ceil_index - 1] & (uint8_t)(0xFF << (8 - zero_bit));
}
free(KS);
*out = stream_cipher->message;
return 0;
}
int stream_encrypt_eea2(stream_cipher_t *stream_cipher, uint8_t **out)
{
uint8_t m[16];
uint32_t local_count;
void *ctx;
uint8_t *data = NULL;
uint32_t zero_bit = 0;
uint32_t byte_length;
DevAssert(stream_cipher != NULL);
DevAssert(out != NULL);
LOG_D(OSA, "Entering stream_encrypt_eea2, bits length %u, bearer %u, "
"count %u, direction %s\n", stream_cipher->blength,
stream_cipher->bearer, stream_cipher->count, stream_cipher->direction == SECU_DIRECTION_DOWNLINK ?
"Downlink" : "Uplink");
zero_bit = stream_cipher->blength & 0x7;
byte_length = stream_cipher->blength >> 3;
if (zero_bit > 0)
byte_length += 1;
ctx = malloc(nettle_aes128.context_size);
if (*out == NULL) {
/* User provided output buffer */
data = malloc(byte_length);
*out = data;
} else {
data = *out;
}
local_count = hton_int32(stream_cipher->count);
memset(m, 0, sizeof(m));
memcpy(&m[0], &local_count, 4);
m[4] = ((stream_cipher->bearer & 0x1F) << 3) |
((stream_cipher->direction & 0x01) << 2);
/* Other bits are 0 */
#if defined(SECU_DEBUG)
{
int i;
char payload[6 * byte_length + 1];
int index = 0;
for (i = 0; i < byte_length; i++)
index += sprintf(&payload[index], "0x%02x ", stream_cipher->message[i]);
LOG_D(OSA, "Original message: %s\n", payload);
}
#endif
#if NETTLE_VERSION_MAJOR < 3
nettle_aes128.set_encrypt_key(ctx, stream_cipher->key_length,
stream_cipher->key);
#else
nettle_aes128.set_encrypt_key(ctx,
stream_cipher->key);
#endif
nettle_ctr_crypt(ctx, nettle_aes128.encrypt,
nettle_aes128.block_size, m,
byte_length, data, stream_cipher->message);
if (zero_bit > 0)
data[byte_length - 1] = data[byte_length - 1] & (uint8_t)(0xFF << (8 - zero_bit));
free(ctx);
#if defined(SECU_DEBUG)
{
int i;
char payload[6 * byte_length + 1];
int index = 0;
for (i = 0; i < byte_length; i++)
index += sprintf(&payload[index], "0x%02x ", data[i]);
LOG_D(OSA, "Encrypted message: %s\n", payload);
}
#endif
return 0;
}
int stream_encrypt(uint8_t algorithm, stream_cipher_t *stream_cipher, uint8_t **out)
{
if (algorithm == EEA0_ALG_ID) {
return stream_encrypt_eea0(stream_cipher, out);
} else if (algorithm == EEA1_128_ALG_ID) {
return stream_encrypt_eea1(stream_cipher, out);
} else if (algorithm == EEA2_128_ALG_ID) {
return stream_encrypt_eea2(stream_cipher, out);
}
LOG_E(OSA, "Provided encryption algorithm is currently not supported = %u\n", algorithm);
return -1;
}