mirror of https://github.com/pvnis/srsRAN_4G.git
Added ue nas base class with security functions
David Rupprecht
3 years ago
committed by
David Rupprecht
parent
7fa85ab336
commit
505225d845
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/**
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*
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* \section COPYRIGHT
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*
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* Copyright 2013-2021 Software Radio Systems Limited
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*
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* By using this file, you agree to the terms and conditions set
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* forth in the LICENSE file which can be found at the top level of
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* the distribution.
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*
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*/
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#ifndef SRSUE_NAS_BASE_H
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#define SRSUE_NAS_BASE_H
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#include "srsran/asn1/liblte_mme.h"
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#include "srsran/common/buffer_pool.h"
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#include "srsran/common/common.h"
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#include "srsran/common/nas_pcap.h"
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#include "srsran/common/security.h"
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#include "srsran/common/string_helpers.h"
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#include "srsran/config.h"
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using srsran::byte_buffer_t;
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namespace srsue {
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class nas_base
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{
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public:
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nas_base(const std::string& type_);
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// PCAP
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void start_pcap(srsran::nas_pcap* pcap_) { pcap = pcap_; }
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protected:
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srslog::basic_logger& logger;
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// PCAP
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srsran::nas_pcap* pcap = nullptr;
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// Security context
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struct nas_sec_ctxt {
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uint8_t ksi;
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uint8_t k_asme[32];
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uint32_t tx_count;
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uint32_t rx_count;
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uint32_t k_enb_count;
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srsran::CIPHERING_ALGORITHM_ID_ENUM cipher_algo;
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srsran::INTEGRITY_ALGORITHM_ID_ENUM integ_algo;
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LIBLTE_MME_EPS_MOBILE_ID_GUTI_STRUCT guti;
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};
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nas_sec_ctxt ctxt = {};
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uint8_t k_nas_enc[32] = {};
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uint8_t k_nas_int[32] = {};
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int parse_security_algorithm_list(std::string algorithm_string, bool* algorithm_caps);
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// Security
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void
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integrity_generate(uint8_t* key_128, uint32_t count, uint8_t direction, uint8_t* msg, uint32_t msg_len, uint8_t* mac);
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bool integrity_check(srsran::byte_buffer_t* pdu);
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void cipher_encrypt(srsran::byte_buffer_t* pdu);
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void cipher_decrypt(srsran::byte_buffer_t* pdu);
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};
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} // namespace srsue
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#endif
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@ -0,0 +1,238 @@
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/**
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*
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* \section COPYRIGHT
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*
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* Copyright 2013-2021 Software Radio Systems Limited
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*
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* By using this file, you agree to the terms and conditions set
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* forth in the LICENSE file which can be found at the top level of
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* the distribution.
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*
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*/
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#include "srsue/hdr/stack/upper/nas_base.h"
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using namespace srsran;
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namespace srsue {
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nas_base::nas_base(const std::string& type_) : logger(srslog::fetch_basic_logger(type_)) {}
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int nas_base::parse_security_algorithm_list(std::string algorithm_string, bool* algorithm_caps)
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{
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// parse and sanity check security algorithm list
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std::vector<uint8_t> cap_list;
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srsran::string_parse_list(algorithm_string, ',', cap_list);
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if (cap_list.empty()) {
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logger.error("Empty security list. Select at least one security algorithm.");
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return SRSRAN_ERROR;
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}
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for (std::vector<uint8_t>::const_iterator it = cap_list.begin(); it != cap_list.end(); ++it) {
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if (*it < 4) {
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algorithm_caps[*it] = true;
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} else {
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logger.error("EEA/EIA/5G-EA/5G-IA %d is not a valid algorithm.", *it);
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return SRSRAN_ERROR;
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}
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}
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return SRSRAN_SUCCESS;
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}
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/*******************************************************************************
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* Security
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******************************************************************************/
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void nas_base::integrity_generate(uint8_t* key_128,
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uint32_t count,
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uint8_t direction,
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uint8_t* msg,
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uint32_t msg_len,
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uint8_t* mac)
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{
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switch (ctxt.integ_algo) {
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case INTEGRITY_ALGORITHM_ID_EIA0:
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break;
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case INTEGRITY_ALGORITHM_ID_128_EIA1:
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security_128_eia1(key_128,
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count,
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0, // Bearer always 0 for NAS
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direction,
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msg,
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msg_len,
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mac);
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break;
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case INTEGRITY_ALGORITHM_ID_128_EIA2:
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security_128_eia2(key_128,
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count,
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0, // Bearer always 0 for NAS
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direction,
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msg,
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msg_len,
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mac);
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break;
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case INTEGRITY_ALGORITHM_ID_128_EIA3:
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security_128_eia3(key_128,
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count,
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0, // Bearer always 0 for NAS
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direction,
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msg,
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msg_len,
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mac);
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break;
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default:
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break;
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}
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}
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// This function depends to a valid k_nas_int.
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// This key is generated in the security mode command.
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bool nas_base::integrity_check(byte_buffer_t* pdu)
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{
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if (pdu == nullptr) {
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logger.error("Invalid PDU");
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return false;
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}
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if (pdu->N_bytes > 5) {
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uint8_t exp_mac[4] = {0};
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uint8_t* mac = &pdu->msg[1];
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// generate expected MAC
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uint32_t count_est = (ctxt.rx_count & 0x00FFFF00u) | pdu->msg[5];
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integrity_generate(
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&k_nas_int[16], count_est, SECURITY_DIRECTION_DOWNLINK, &pdu->msg[5], pdu->N_bytes - 5, &exp_mac[0]);
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// Check if expected mac equals the sent mac
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for (int i = 0; i < 4; i++) {
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if (exp_mac[i] != mac[i]) {
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logger.warning("Integrity check failure. Local: count=%d, [%02x %02x %02x %02x], "
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"Received: count=%d, [%02x %02x %02x %02x]",
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count_est,
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exp_mac[0],
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exp_mac[1],
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exp_mac[2],
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exp_mac[3],
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pdu->msg[5],
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mac[0],
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mac[1],
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mac[2],
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mac[3]);
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return false;
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}
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}
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logger.info("Integrity check ok. Local: count=%d, Received: count=%d [%02x %02x %02x %02x]",
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count_est,
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pdu->msg[5],
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mac[0],
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mac[1],
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mac[2],
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mac[3]);
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// Updated local count (according to TS 24.301 Sec. 4.4.3.3)
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if (count_est != ctxt.rx_count) {
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logger.info("Update local count to estimated count %d", count_est);
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ctxt.rx_count = count_est;
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}
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return true;
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} else {
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logger.error("Invalid integrity check PDU size (%d)", pdu->N_bytes);
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return false;
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}
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}
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void nas_base::cipher_encrypt(byte_buffer_t* pdu)
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{
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byte_buffer_t pdu_tmp;
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if (ctxt.cipher_algo != CIPHERING_ALGORITHM_ID_EEA0) {
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logger.debug("Encrypting PDU. count=%d", ctxt.tx_count);
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}
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switch (ctxt.cipher_algo) {
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case CIPHERING_ALGORITHM_ID_EEA0:
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break;
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case CIPHERING_ALGORITHM_ID_128_EEA1:
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security_128_eea1(&k_nas_enc[16],
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ctxt.tx_count,
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0, // Bearer always 0 for NAS
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SECURITY_DIRECTION_UPLINK,
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&pdu->msg[6],
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pdu->N_bytes - 6,
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&pdu_tmp.msg[6]);
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memcpy(&pdu->msg[6], &pdu_tmp.msg[6], pdu->N_bytes - 6);
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break;
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case CIPHERING_ALGORITHM_ID_128_EEA2:
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security_128_eea2(&k_nas_enc[16],
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ctxt.tx_count,
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0, // Bearer always 0 for NAS
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SECURITY_DIRECTION_UPLINK,
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&pdu->msg[6],
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pdu->N_bytes - 6,
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&pdu_tmp.msg[6]);
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memcpy(&pdu->msg[6], &pdu_tmp.msg[6], pdu->N_bytes - 6);
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break;
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case CIPHERING_ALGORITHM_ID_128_EEA3:
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security_128_eea3(&k_nas_enc[16],
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ctxt.tx_count,
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0, // Bearer always 0 for NAS
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SECURITY_DIRECTION_UPLINK,
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&pdu->msg[6],
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pdu->N_bytes - 6,
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&pdu_tmp.msg[6]);
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memcpy(&pdu->msg[6], &pdu_tmp.msg[6], pdu->N_bytes - 6);
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break;
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default:
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logger.error("Ciphering algorithm not known");
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break;
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}
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}
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void nas_base::cipher_decrypt(byte_buffer_t* pdu)
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{
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byte_buffer_t tmp_pdu;
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uint32_t count_est = (ctxt.rx_count & 0x00FFFF00u) | pdu->msg[5];
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if (ctxt.cipher_algo != CIPHERING_ALGORITHM_ID_EEA0) {
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logger.debug("Decrypting PDU. Local: count=%d, Received: count=%d", ctxt.rx_count, count_est);
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}
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switch (ctxt.cipher_algo) {
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case CIPHERING_ALGORITHM_ID_EEA0:
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break;
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case CIPHERING_ALGORITHM_ID_128_EEA1:
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security_128_eea1(&k_nas_enc[16],
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count_est,
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0, // Bearer always 0 for NAS
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SECURITY_DIRECTION_DOWNLINK,
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&pdu->msg[6],
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pdu->N_bytes - 6,
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&tmp_pdu.msg[6]);
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memcpy(&pdu->msg[6], &tmp_pdu.msg[6], pdu->N_bytes - 6);
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break;
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case CIPHERING_ALGORITHM_ID_128_EEA2:
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security_128_eea2(&k_nas_enc[16],
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count_est,
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0, // Bearer always 0 for NAS
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SECURITY_DIRECTION_DOWNLINK,
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&pdu->msg[6],
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pdu->N_bytes - 6,
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&tmp_pdu.msg[6]);
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logger.debug(tmp_pdu.msg, pdu->N_bytes, "Decrypted");
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memcpy(&pdu->msg[6], &tmp_pdu.msg[6], pdu->N_bytes - 6);
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break;
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case CIPHERING_ALGORITHM_ID_128_EEA3:
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security_128_eea3(&k_nas_enc[16],
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count_est,
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0, // Bearer always 0 for NAS
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SECURITY_DIRECTION_DOWNLINK,
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&pdu->msg[6],
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pdu->N_bytes - 6,
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&tmp_pdu.msg[6]);
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logger.debug(tmp_pdu.msg, pdu->N_bytes, "Decrypted");
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memcpy(&pdu->msg[6], &tmp_pdu.msg[6], pdu->N_bytes - 6);
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break;
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default:
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logger.error("Ciphering algorithms not known");
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break;
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}
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}
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} // namespace srsue
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