tls_ccm_crypt.c

00001 /*
00002  * Copyright (c) 2017-2018, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 #include "nsconfig.h"
00018 #include "ns_types.h"
00019 #ifdef PANA
00020 #include "ns_trace.h"
00021 #include "string.h"
00022 #include "ccmLIB.h"
00023 #include "ns_trace.h"
00024 #include "common_functions.h"
00025 
00026 #define CLIENT_WRITE_KEY    0
00027 #define SERVER_WRITE_KEY    16
00028 #define CLIENT_IV           32
00029 #define SERVER_IV           36
00030 #define TRACE_GROUP "cryp"
00031 #define TLS_1_2_VER                 0x0303
00032 
00033 static bool tls_ccm_init(ccm_globals_t *ccm_ptr, const uint8_t *key_expansion, const uint8_t *nonce, bool server, uint8_t crypt_process)
00034 {
00035     const uint8_t *key, *iv_ptr;
00036     if (server) {
00037         key = key_expansion + SERVER_WRITE_KEY;
00038         iv_ptr = key_expansion + SERVER_IV;
00039     } else {
00040         key = key_expansion + CLIENT_WRITE_KEY;
00041         iv_ptr = key_expansion + CLIENT_IV;
00042     }
00043 
00044     if (!ccm_sec_init(ccm_ptr, AES_SECURITY_LEVEL_ENC_MIC64, key, crypt_process, 3)) {
00045         return false;
00046     }
00047 
00048     memcpy(ccm_ptr->exp_nonce, iv_ptr, 4);
00049     memcpy(&ccm_ptr->exp_nonce[4], nonce, 8);
00050     return true;
00051 }
00052 
00053 
00054 static void tls_set_adata(ccm_globals_t *ccm_ptr, uint8_t *a_data, const uint8_t *nonce, uint8_t type)
00055 {
00056     ccm_ptr->adata_len = 13;
00057     ccm_ptr->adata_ptr = a_data;
00058     memcpy(a_data, nonce, 8);
00059     a_data += 8;
00060     *a_data++ = type;
00061     a_data = common_write_16_bit(TLS_1_2_VER, a_data);
00062     common_write_16_bit(ccm_ptr->data_len, a_data);
00063 }
00064 
00065 
00066 int8_t tls_ccm_data_encrypt(uint8_t *data_ptr, uint16_t data_length, const uint8_t *key_expansion, const uint8_t *nonce, uint8_t type, bool server)
00067 {
00068     ccm_globals_t ccm_ptr;
00069     if (!tls_ccm_init(&ccm_ptr, key_expansion, nonce, server, AES_CCM_ENCRYPT)) {
00070         return -1;
00071     }
00072     uint8_t adata[13];
00073     ccm_ptr.data_len = data_length;
00074     ccm_ptr.data_ptr  = data_ptr;
00075     ccm_ptr.mic = (ccm_ptr.data_ptr + ccm_ptr.data_len);
00076     tls_set_adata(&ccm_ptr, adata, nonce, type);
00077     return ccm_process_run(&ccm_ptr);
00078 }
00079 
00080 int8_t tls_ccm_data_decrypt(uint8_t *data_ptr, uint16_t data_length, const uint8_t *key_expansion, uint8_t type, bool server)
00081 {
00082 
00083     if (data_length <= 16) {
00084         return -1;
00085     }
00086     ccm_globals_t ccm_ptr;
00087 
00088     if (!tls_ccm_init(&ccm_ptr, key_expansion, data_ptr, server, AES_CCM_DECRYPT)) {
00089         return -1;
00090     }
00091 
00092     uint8_t adata[13];
00093     ccm_ptr.data_len = data_length - 16;
00094 
00095     tls_set_adata(&ccm_ptr, adata, data_ptr, type);
00096     ccm_ptr.data_ptr  = data_ptr + 8;
00097     ccm_ptr.mic = (ccm_ptr.data_ptr + ccm_ptr.data_len);
00098 
00099     return ccm_process_run(&ccm_ptr);
00100 }
00101 #endif