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srsRAN_4G
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start with decryption function

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master
David Rupprecht 6 years ago
parent 1c015aab62
commit 7eef2c1c4b
2 changed files with 94 additions and 7 deletions
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3
srsepc/hdr/mme/s1ap_nas_transport.h
Unescape Escape View File

@ -128,6 +128,9 @@ private:
void log_unhandled_attach_request_ies(const LIBLTE_MME_ATTACH_REQUEST_MSG_STRUCT *attach_req);
void log_unhandled_pdn_con_request_ies(const LIBLTE_MME_PDN_CONNECTIVITY_REQUEST_MSG_STRUCT *pdn_con_req);
void log_unhandled_initial_ue_message_ies(LIBLTE_S1AP_MESSAGE_INITIALUEMESSAGE_STRUCT *init_ue);
void cipher_decrypt(eps_sec_ctx_t *sec_ctxt, srslte::byte_buffer_t *pdu);
void cipher_encrypt(eps_sec_ctx_t *sec_ctxt, srslte::byte_buffer_t *pdu);
};
} //namespace srsepc
#endif // SRSEPC_S1AP_NAS_TRANSPORT_H

98
srsepc/src/mme/s1ap_nas_transport.cc
Unescape Escape View File

@ -264,18 +264,25 @@ s1ap_nas_transport::handle_uplink_nas_transport(LIBLTE_S1AP_MESSAGE_UPLINKNASTRA
}
else if(sec_hdr_type == LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY_WITH_NEW_EPS_SECURITY_CONTEXT || sec_hdr_type == LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY_AND_CIPHERED_WITH_NEW_EPS_SECURITY_CONTEXT)
{
mac_valid = integrity_check(emm_ctx, nas_msg);
if (mac_valid == false){
m_s1ap_log->warning("Invalid MAC message.\n" );
return false;
}
if (sec_hdr_type == LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY_AND_CIPHERED_WITH_NEW_EPS_SECURITY_CONTEXT) {
cipher_decrypt(&emm_ctx->security_ctxt, nas_msg);
liblte_mme_parse_msg_header((LIBLTE_BYTE_MSG_STRUCT *) nas_msg, &pd, &msg_type);
}
switch (msg_type) {
case LIBLTE_MME_MSG_TYPE_SECURITY_MODE_COMPLETE:
m_s1ap_log->info("Uplink NAS: Received Security Mode Complete\n");
m_s1ap_log->console("Uplink NAS: Received Security Mode Complete\n");
emm_ctx->security_ctxt.ul_nas_count = 0;
emm_ctx->security_ctxt.dl_nas_count = 0;
mac_valid = integrity_check(emm_ctx,nas_msg);
if(mac_valid){
handle_nas_security_mode_complete(nas_msg, ue_ctx, reply_buffer, reply_flag);
} else {
m_s1ap_log->warning("Invalid MAC in Security Mode Command Complete message.\n" );
}
handle_nas_security_mode_complete(nas_msg, ue_ctx, reply_buffer, reply_flag);
break;
default:
m_s1ap_log->warning("Unhandled NAS message with new EPS security context 0x%x\n", msg_type );
@ -287,11 +294,17 @@ s1ap_nas_transport::handle_uplink_nas_transport(LIBLTE_S1AP_MESSAGE_UPLINKNASTRA
//Integrity protected NAS message, possibly ciphered.
emm_ctx->security_ctxt.ul_nas_count++;
mac_valid = integrity_check(emm_ctx,nas_msg);
if(!mac_valid){
if(mac_valid == false){
m_s1ap_log->warning("Invalid MAC in NAS message type 0x%x.\n", msg_type);
m_pool->deallocate(nas_msg);
return false;
}
if(sec_hdr_type == LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY_AND_CIPHERED){
cipher_decrypt(&emm_ctx->security_ctxt, nas_msg);
liblte_mme_parse_msg_header((LIBLTE_BYTE_MSG_STRUCT *) nas_msg, &pd, &msg_type);
}
switch (msg_type) {
case LIBLTE_MME_MSG_TYPE_ATTACH_COMPLETE:
m_s1ap_log->info("Integrity Protected UL NAS: Received Attach Complete\n");
@ -2136,6 +2149,77 @@ s1ap_nas_transport::log_unhandled_attach_request_ies(const LIBLTE_MME_ATTACH_REQ
return;
}
void s1ap_nas_transport::cipher_decrypt(eps_sec_ctx_t * sec_ctxt, srslte::byte_buffer_t *pdu)
{
srslte::byte_buffer_t tmp_pdu;
switch(sec_ctxt->cipher_algo)
{
case srslte::CIPHERING_ALGORITHM_ID_EEA0:
break;
case srslte::CIPHERING_ALGORITHM_ID_128_EEA1:
srslte::security_128_eea1(&sec_ctxt->k_nas_enc[16],
pdu->msg[5],
0, // Bearer always 0 for NAS
SECURITY_DIRECTION_UPLINK,
&pdu->msg[6],
pdu->N_bytes-6,
&tmp_pdu.msg[6]);
memcpy(&pdu->msg[6], &tmp_pdu.msg[6], pdu->N_bytes-6);
m_s1ap_log->debug_hex(tmp_pdu.msg, pdu->N_bytes, "Decrypted");
break;
case srslte::CIPHERING_ALGORITHM_ID_128_EEA2:
srslte::security_128_eea2(&sec_ctxt->k_nas_enc[16],
pdu->msg[5],
0, // Bearer always 0 for NAS
SECURITY_DIRECTION_UPLINK,
&pdu->msg[6],
pdu->N_bytes-6,
&tmp_pdu.msg[6]);
m_s1ap_log->debug_hex(tmp_pdu.msg, pdu->N_bytes, "Decrypted");
memcpy(&pdu->msg[6], &tmp_pdu.msg[6], pdu->N_bytes-6);
break;
default:
m_s1ap_log->error("Ciphering algorithms not known\n");
break;
}
}
void s1ap_nas_transport::cipher_encrypt(eps_sec_ctx_t * sec_ctxt, srslte::byte_buffer_t *pdu)
{
srslte::byte_buffer_t pdu_tmp;
switch(sec_ctxt->cipher_algo)
{
case srslte::CIPHERING_ALGORITHM_ID_EEA0:
break;
case srslte::CIPHERING_ALGORITHM_ID_128_EEA1:
srslte::security_128_eea1(&sec_ctxt->k_nas_enc[16],
pdu->msg[5],
0, // Bearer always 0 for NAS
SECURITY_DIRECTION_DOWNLINK,
&pdu->msg[6],
pdu->N_bytes-6,
&pdu_tmp.msg[6]);
memcpy(&pdu->msg[6], &pdu_tmp.msg[6], pdu->N_bytes-6);
m_s1ap_log->debug_hex(pdu_tmp.msg, pdu->N_bytes, "Encrypted");
break;
case srslte::CIPHERING_ALGORITHM_ID_128_EEA2:
srslte::security_128_eea2(&sec_ctxt->k_nas_enc[16],
pdu->msg[5],
0, // Bearer always 0 for NAS
SECURITY_DIRECTION_DOWNLINK,
&pdu->msg[6],
pdu->N_bytes-6,
&pdu_tmp.msg[6]);
memcpy(&pdu->msg[6], &pdu_tmp.msg[6], pdu->N_bytes-6);
m_s1ap_log->debug_hex(pdu_tmp.msg, pdu->N_bytes, "Encrypted");
break;
default:
m_s1ap_log->error("Ciphering algorithm not known\n");
break;
}
}
void
s1ap_nas_transport::log_unhandled_pdn_con_request_ies(const LIBLTE_MME_PDN_CONNECTIVITY_REQUEST_MSG_STRUCT *pdn_con_req)
{

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