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epc,s1ap,nas: reduce the logging level of MAC failures on identity response and authentication response

Browse Source
master
Pedro Alvarez 3 years ago
parent 8a5ecfea40
commit 2d42766b2e
3 changed files with 46 additions and 34 deletions
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2
srsepc/hdr/mme/nas.h
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@ -238,7 +238,7 @@ public:
bool pack_attach_accept(srsran::byte_buffer_t* nas_buffer);
/* Security functions */
bool integrity_check(srsran::byte_buffer_t* pdu);
bool integrity_check(srsran::byte_buffer_t* pdu, bool warn_failure = true);
bool short_integrity_check(srsran::byte_buffer_t* pdu);
void integrity_generate(srsran::byte_buffer_t* pdu, uint8_t* mac);
void cipher_decrypt(srsran::byte_buffer_t* pdu);

35
srsepc/src/mme/nas.cc
Unescape Escape View File

@ -1427,8 +1427,8 @@ bool nas::pack_security_mode_command(srsran::byte_buffer_t* nas_buffer)
sm_cmd.imeisv_req = LIBLTE_MME_IMEISV_REQUESTED;
}
sm_cmd.nonce_ue_present = false;
sm_cmd.nonce_mme_present = false;
sm_cmd.nonce_ue_present = false;
sm_cmd.nonce_mme_present = false;
uint8_t sec_hdr_type = 3;
LIBLTE_ERROR_ENUM err = liblte_mme_pack_security_mode_command_msg(
@ -1805,7 +1805,7 @@ bool nas::short_integrity_check(srsran::byte_buffer_t* pdu)
return true;
}
bool nas::integrity_check(srsran::byte_buffer_t* pdu)
bool nas::integrity_check(srsran::byte_buffer_t* pdu, bool warn_failure)
{
uint8_t exp_mac[4] = {};
const uint8_t* mac = &pdu->msg[1];
@ -1848,20 +1848,21 @@ bool nas::integrity_check(srsran::byte_buffer_t* pdu)
// Check if expected mac equals the sent mac
for (int i = 0; i < 4; i++) {
if (exp_mac[i] != mac[i]) {
m_logger.warning("Integrity check failure. Algorithm=EIA%d", (int)m_sec_ctx.integ_algo);
m_logger.warning("UL Local: est_count=%d, old_count=%d, MAC=[%02x %02x %02x %02x], "
"Received: UL count=%d, MAC=[%02x %02x %02x %02x]",
estimated_count,
m_sec_ctx.ul_nas_count,
exp_mac[0],
exp_mac[1],
exp_mac[2],
exp_mac[3],
pdu->msg[5],
mac[0],
mac[1],
mac[2],
mac[3]);
srslog::log_channel& channel = warn_failure ? m_logger.warning : m_logger.info;
channel("Integrity check failure. Algorithm=EIA%d", (int)m_sec_ctx.integ_algo);
channel("UL Local: est_count=%d, old_count=%d, MAC=[%02x %02x %02x %02x], "
"Received: UL count=%d, MAC=[%02x %02x %02x %02x]",
estimated_count,
m_sec_ctx.ul_nas_count,
exp_mac[0],
exp_mac[1],
exp_mac[2],
exp_mac[3],
pdu->msg[5],
mac[0],
mac[1],
mac[2],
mac[3]);
return false;
}
}

43
srsepc/src/mme/s1ap_nas_transport.cc
Unescape Escape View File

@ -59,18 +59,18 @@ void s1ap_nas_transport::init()
m_s1ap = s1ap::get_instance();
// Init NAS args
m_nas_init.mcc = m_s1ap->m_s1ap_args.mcc;
m_nas_init.mnc = m_s1ap->m_s1ap_args.mnc;
m_nas_init.mme_code = m_s1ap->m_s1ap_args.mme_code;
m_nas_init.mme_group = m_s1ap->m_s1ap_args.mme_group;
m_nas_init.tac = m_s1ap->m_s1ap_args.tac;
m_nas_init.apn = m_s1ap->m_s1ap_args.mme_apn;
m_nas_init.dns = m_s1ap->m_s1ap_args.dns_addr;
m_nas_init.mcc = m_s1ap->m_s1ap_args.mcc;
m_nas_init.mnc = m_s1ap->m_s1ap_args.mnc;
m_nas_init.mme_code = m_s1ap->m_s1ap_args.mme_code;
m_nas_init.mme_group = m_s1ap->m_s1ap_args.mme_group;
m_nas_init.tac = m_s1ap->m_s1ap_args.tac;
m_nas_init.apn = m_s1ap->m_s1ap_args.mme_apn;
m_nas_init.dns = m_s1ap->m_s1ap_args.dns_addr;
m_nas_init.full_net_name = m_s1ap->m_s1ap_args.full_net_name;
m_nas_init.short_net_name = m_s1ap->m_s1ap_args.short_net_name;
m_nas_init.paging_timer = m_s1ap->m_s1ap_args.paging_timer;
m_nas_init.integ_algo = m_s1ap->m_s1ap_args.integrity_algo;
m_nas_init.cipher_algo = m_s1ap->m_s1ap_args.encryption_algo;
m_nas_init.paging_timer = m_s1ap->m_s1ap_args.paging_timer;
m_nas_init.integ_algo = m_s1ap->m_s1ap_args.integrity_algo;
m_nas_init.cipher_algo = m_s1ap->m_s1ap_args.encryption_algo;
m_nas_init.request_imeisv = m_s1ap->m_s1ap_args.request_imeisv;
// Init NAS interface
@ -170,17 +170,28 @@ bool s1ap_nas_transport::handle_uplink_nas_transport(const asn1::s1ap::ul_nas_tr
m_logger.error("Unhandled security header type in Uplink NAS Transport: %d", sec_hdr_type);
return false;
}
// Todo: Check on count mismatch of uplink count and do resync nas counter...
// Some messages may have invalid MAC. Check wether we need to warn about MAC failures.
bool warn_integrity_fail = true;
if (sec_hdr_type == LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY ||
sec_hdr_type == LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY_WITH_NEW_EPS_SECURITY_CONTEXT) {
// Avoid unecessary warnings for identity response and authentication response.
liblte_mme_parse_msg_header((LIBLTE_BYTE_MSG_STRUCT*)nas_msg.get(), &pd, &msg_type);
if (msg_type == LIBLTE_MME_MSG_TYPE_IDENTITY_RESPONSE || msg_type == LIBLTE_MME_MSG_TYPE_AUTHENTICATION_RESPONSE) {
warn_integrity_fail = false;
}
}
// Check MAC if message is integrity protected
if (sec_hdr_type == LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY ||
sec_hdr_type == LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY_AND_CIPHERED ||
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 ||
sec_hdr_type == LIBLTE_MME_SECURITY_HDR_TYPE_INTEGRITY_AND_CIPHERED_WITH_NEW_EPS_SECURITY_CONTEXT) {
mac_valid = nas_ctx->integrity_check(nas_msg.get());
if (mac_valid == false) {
m_logger.warning("Invalid MAC message. Even if security header indicates integrity protection (Maybe: "
"Identity Response or Authentication Response)");
mac_valid = nas_ctx->integrity_check(nas_msg.get(), warn_integrity_fail);
if (not mac_valid) {
srslog::log_channel& channel = warn_integrity_fail ? m_logger.warning : m_logger.info;
channel("Invalid MAC message. Even if security header indicates integrity protection (Maybe: "
"Identity Response or Authentication Response)");
}
}

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