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rlm_eap_aka.c
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rlm_eap_aka.c
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/*
* This program is is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
/**
* $Id$
* @file rlm_eap_aka.c
* @brief Implements the AKA part of EAP-AKA
*
* @author Arran Cudbard-Bell <a.cudbardb@freeradius.org>
*
* @copyright 2016 The FreeRADIUS server project
* @copyright 2016 Network RADIUS SARL <sales@networkradius.com>
*/
RCSID("$Id$")
#include "../../eap.h"
#include "eap_types.h"
#include "eap_aka.h"
#include "sim_proto.h"
#include <freeradius-devel/rad_assert.h>
#ifndef EAP_TLS_MPPE_KEY_LEN
# define EAP_TLS_MPPE_KEY_LEN 32
#endif
FR_NAME_NUMBER const aka_state_table[] = {
{ "IDENTITY", EAP_AKA_SERVER_IDENTITY },
{ "CHALLENGE", EAP_AKA_SERVER_CHALLENGE },
{ "SUCCESS-NOTIFICATION", EAP_AKA_SERVER_SUCCESS_NOTIFICATION },
{ "SUCCESS", EAP_AKA_SERVER_SUCCESS },
{ "FAILURE-NOTIFICATION", EAP_AKA_SERVER_FAILURE_NOTIFICATION },
{ "FAILURE", EAP_AKA_SERVER_FAILURE },
{ NULL }
};
static rlm_rcode_t mod_process(UNUSED void *arg, eap_session_t *eap_session);
static CONF_PARSER submodule_config[] = {
{ FR_CONF_OFFSET("network_id", FR_TYPE_STRING | FR_TYPE_REQUIRED, rlm_eap_aka_t, network_id ) },
{ FR_CONF_OFFSET("request_identity", FR_TYPE_BOOL, rlm_eap_aka_t, request_identity ), .dflt = "no" },
{ FR_CONF_OFFSET("protected_success", FR_TYPE_BOOL, rlm_eap_aka_t, protected_success ), .dflt = "no" },
{ FR_CONF_OFFSET("virtual_server", FR_TYPE_STRING, rlm_eap_aka_t, virtual_server) },
CONF_PARSER_TERMINATOR
};
static int eap_aka_compose(eap_session_t *eap_session)
{
eap_aka_session_t *eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
vp_cursor_t cursor;
vp_cursor_t to_encode;
VALUE_PAIR *head = NULL, *vp;
REQUEST *request = eap_session->request;
ssize_t ret;
fr_sim_encode_ctx_t encoder_ctx = {
.root = dict_aka_root,
.keys = &eap_aka_session->keys,
.iv = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
.iv_included = false,
.hmac_md = eap_aka_session->mac_md,
.eap_packet = eap_session->this_round->request,
.hmac_extra = NULL,
.hmac_extra_len = 0
};
fr_dict_attr_t const *encr = fr_dict_attr_child_by_num(dict_sim_root, FR_EAP_AKA_ENCR_DATA);
fr_pair_cursor_init(&cursor, &eap_session->request->reply->vps);
fr_pair_cursor_init(&to_encode, &head);
while ((fr_pair_cursor_next_by_ancestor(&cursor, dict_aka_root, TAG_ANY))) {
vp = fr_pair_cursor_remove(&cursor);
/*
* Silently discard encrypted attributes until
* the peer should have k_encr. These can be
* added by policy, and seem to cause
* wpa_supplicant to fail if sent before the challenge.
*/
if (!eap_aka_session->allow_encrypted && fr_dict_parent_common(encr, vp->da, true)) {
talloc_free(vp);
continue;
}
fr_pair_cursor_append(&to_encode, vp);
}
RDEBUG2("Encoding EAP-AKA attributes");
rdebug_pair_list(L_DBG_LVL_2, request, head, NULL);
eap_session->this_round->request->type.num = eap_aka_session->type;
eap_session->this_round->request->id = eap_aka_session->aka_id++ & 0xff;
eap_session->this_round->set_request_id = true;
ret = fr_sim_encode(eap_session->request, head, &encoder_ctx);
fr_pair_cursor_first(&to_encode);
fr_pair_cursor_free(&to_encode);
if (ret < 0) {
RPEDEBUG("Failed encoding EAP-AKA data");
return -1;
}
return 0;
}
/** Send an EAP-AKA identity request to the supplicant
*
* There are three types of user identities that can be implemented
* - Permanent identities such as 0123456789098765@myoperator.com
* Permanent identities can be identified by the leading zero followed by
* by 15 digits (the IMSI number).
* - Ephemeral identities (pseudonyms). These are identities assigned for
* identity privacy so the user can't be tracked. These can identities
* can either be generated as per the 3GPP 'Security aspects of non-3GPP accesses'
* document section 14, where a set of up to 16 encryption keys are used
* to reversibly encrypt the IMSI. Alternatively the pseudonym can be completely
* randomised and stored in a datastore.
* - A fast resumption ID which resolves to data used for fast resumption.
*
* In order to perform full authentication the original IMSI is required for
* forwarding to the HLR. In the case where we can't match/decrypt the pseudonym,
* or can't perform fast resumption, we need to request the full identity from
* the supplicant.
*
* @param[in] eap_session to continue.
* @return
* - 0 on success.
* - <0 on failure.
*/
static int eap_aka_send_identity_request(eap_session_t *eap_session)
{
REQUEST *request = eap_session->request;
eap_aka_session_t *eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
VALUE_PAIR *vp;
RADIUS_PACKET *packet;
fr_cursor_t cursor;
RDEBUG2("Sending AKA-Identity (%s)", fr_int2str(sim_id_request_table, eap_aka_session->id_req, "<INVALID>"));
eap_session->this_round->request->code = FR_EAP_CODE_REQUEST;
eap_aka_session->allow_encrypted = false; /* In case this is after failed fast-resumption */
packet = request->reply;
fr_cursor_init(&cursor, &packet->vps);
/*
* Set the subtype to identity request
*/
vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_SUBTYPE);
vp->vp_uint16 = FR_EAP_AKA_SUBTYPE_VALUE_AKA_IDENTITY;
fr_cursor_append(&cursor, vp);
/*
* Select the right type of identity request attribute
*/
switch (eap_aka_session->id_req) {
case SIM_ANY_ID_REQ:
vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_ANY_ID_REQ);
break;
case SIM_PERMANENT_ID_REQ:
vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_PERMANENT_ID_REQ);
break;
case SIM_FULLAUTH_ID_REQ:
vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_FULLAUTH_ID_REQ);
break;
default:
rad_assert(0);
}
vp->vp_bool = true;
fr_cursor_append(&cursor, vp);
/*
* Encode the packet
*/
if (eap_aka_compose(eap_session) < 0) {
failure:
fr_pair_list_free(&packet->vps);
return -1;
}
/*
* Digest the packet contents, updating our checkcode.
*/
if (!eap_aka_session->checkcode_state &&
fr_sim_crypto_init_checkcode(eap_aka_session, &eap_aka_session->checkcode_state,
eap_aka_session->checkcode_md) < 0) {
RPEDEBUG("Failed initialising checkcode");
goto failure;
}
if (fr_sim_crypto_update_checkcode(eap_aka_session->checkcode_state, eap_session->this_round->request) < 0) {
RPEDEBUG("Failed updating checkcode");
goto failure;
}
return 0;
}
/** Send the challenge itself
*
* Challenges will come from one of three places eventually:
*
* 1 from attributes like FR_EAP_AKA_RANDx
* (these might be retrieved from a database)
*
* 2 from internally implemented SIM authenticators
* (a simple one based upon XOR will be provided)
*
* 3 from some kind of SS7 interface.
*
* For now, they only come from attributes.
* It might be that the best way to do 2/3 will be with a different
* module to generate/calculate things.
*/
static int eap_aka_send_challenge(eap_session_t *eap_session)
{
static uint8_t hmac_zero[16] = { 0x00 };
REQUEST *request = eap_session->request;
eap_aka_session_t *eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
VALUE_PAIR **to_peer, *vp;
RADIUS_PACKET *packet;
fr_sim_vector_src_t src = SIM_VECTOR_SRC_AUTO;
rad_assert(request);
rad_assert(request->reply);
/*
* to_peer is the data to the client
*/
packet = eap_session->request->reply;
to_peer = &packet->vps;
RDEBUG2("Acquiring UMTS vector(s)");
/*
* Toggle the AMF high bit to indicate we're doing AKA'
*/
if (eap_aka_session->type == FR_EAP_AKA_PRIME) {
uint8_t amf_buff[2] = { 0x80, 0x00 }; /* Set the AMF separation bit high */
vp = fr_pair_afrom_child_num(packet, fr_dict_root(fr_dict_internal), FR_SIM_AMF);
fr_pair_value_memcpy(vp, amf_buff, sizeof(amf_buff));
fr_pair_replace(&request->control, vp);
}
/*
* Get vectors from attribute or generate
* them using COMP128-* or Milenage.
*/
if (fr_sim_vector_umts_from_attrs(eap_session, request->control, &eap_aka_session->keys, &src) < 0) {
REDEBUG("Failed retrieving UMTS vectors");
return RLM_MODULE_FAIL;
}
/*
* Don't leave the AMF hanging around
*/
if (eap_aka_session->type == FR_EAP_AKA_PRIME) fr_pair_delete_by_num(&request->control, 0, FR_SIM_AMF, TAG_ANY);
/*
* All set, calculate keys!
*/
switch (eap_aka_session->kdf) {
case FR_EAP_AKA_KDF_VALUE_EAP_AKA_PRIME_WITH_CK_PRIME_IK_PRIME:
fr_sim_crypto_kdf_1_umts(&eap_aka_session->keys);
break;
default:
fr_sim_crypto_kdf_0_umts(&eap_aka_session->keys);
break;
}
if (RDEBUG_ENABLED3) fr_sim_crypto_keys_log(request, &eap_aka_session->keys);
RDEBUG2("Sending AKA-Challenge");
eap_session->this_round->request->code = FR_EAP_CODE_REQUEST;
/*
* Set the subtype to challenge
*/
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_SUBTYPE));
vp->vp_uint16 = FR_EAP_AKA_SUBTYPE_VALUE_AKA_CHALLENGE;
fr_pair_replace(to_peer, vp);
/*
* Indicate we'd like to use protected success messages
*/
if (eap_aka_session->send_result_ind) {
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_RESULT_IND));
vp->vp_bool = true;
fr_pair_replace(to_peer, vp);
}
/*
* We support EAP-AKA' and the peer should use that
* if it's able to...
*/
if (eap_aka_session->send_at_bidding) {
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_BIDDING));
vp->vp_uint16 = FR_EAP_AKA_BIDDING_VALUE_PREFER_AKA_PRIME;
fr_pair_replace(to_peer, vp);
}
/*
* Send the network name and KDF to the peer
*/
if (eap_aka_session->type == FR_EAP_AKA_PRIME) {
if (!eap_aka_session->keys.network_len) {
REDEBUG2("No network name available, can't set EAP-AKA-KDF-Input");
failure:
fr_pair_list_free(&packet->vps);
return -1;
}
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_KDF_INPUT));
fr_pair_value_bstrncpy(vp, eap_aka_session->keys.network, eap_aka_session->keys.network_len);
fr_pair_replace(to_peer, vp);
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_KDF));
vp->vp_uint16 = eap_aka_session->kdf;
fr_pair_replace(to_peer, vp);
}
/*
* Okay, we got the challenge! Put it into an attribute.
*/
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_RAND));
fr_pair_value_memcpy(vp, eap_aka_session->keys.umts.vector.rand, SIM_VECTOR_UMTS_RAND_SIZE);
fr_pair_replace(to_peer, vp);
/*
* Send the AUTN value to the client, so it can authenticate
* whoever has knowledge of the Ki.
*/
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_AUTN));
fr_pair_value_memcpy(vp, eap_aka_session->keys.umts.vector.autn, SIM_VECTOR_UMTS_AUTN_SIZE);
fr_pair_replace(to_peer, vp);
/*
* need to include an AT_MAC attribute so that it will get
* calculated.
*/
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_MAC));
fr_pair_value_memcpy(vp, hmac_zero, sizeof(hmac_zero));
fr_pair_replace(to_peer, vp);
/*
* If we have checkcode data, send that to the peer
* for validation.
*/
if (eap_aka_session->checkcode_state) {
ssize_t slen;
slen = fr_sim_crypto_finalise_checkcode(eap_aka_session->checkcode, &eap_aka_session->checkcode_state);
if (slen < 0) {
RPEDEBUG("Failed calculating checkcode");
goto failure;
}
eap_aka_session->checkcode_len = slen;
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_CHECKCODE));
fr_pair_value_memcpy(vp, eap_aka_session->checkcode, slen);
/*
* If we don't have checkcode data, then we exchanged
* no identity packets, so checkcode is zero.
*/
} else {
MEM(vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_CHECKCODE));
eap_aka_session->checkcode_len = 0;
}
fr_pair_replace(to_peer, vp);
/*
* We've sent the challenge so the peer should now be able
* to accept encrypted attributes.
*/
eap_aka_session->allow_encrypted = true;
/*
* Encode the packet
*/
if (eap_aka_compose(eap_session) < 0) goto failure;
return 0;
}
/** Send a success notification
*
*/
static int eap_aka_send_eap_success_notification(eap_session_t *eap_session)
{
REQUEST *request = eap_session->request;
RADIUS_PACKET *packet = eap_session->request->reply;
eap_aka_session_t *eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
fr_cursor_t cursor;
VALUE_PAIR *vp;
RDEBUG2("Sending AKA-Notification (Success)");
eap_session->this_round->request->code = FR_EAP_CODE_REQUEST;
if (!fr_cond_assert(eap_aka_session->challenge_success)) return -1;
fr_cursor_init(&cursor, &packet->vps);
/*
* Set the subtype to notification
*/
vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_SUBTYPE);
vp->vp_uint16 = FR_EAP_AKA_SUBTYPE_VALUE_AKA_NOTIFICATION;
fr_cursor_append(&cursor, vp);
vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_NOTIFICATION);
vp->vp_uint16 = FR_EAP_AKA_NOTIFICATION_VALUE_SUCCESS;
fr_cursor_append(&cursor, vp);
/*
* Need to include an AT_MAC attribute so that it will get
* calculated.
*/
vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_MAC);
fr_pair_replace(&packet->vps, vp);
/*
* Encode the packet
*/
if (eap_aka_compose(eap_session) < 0) {
fr_pair_list_free(&packet->vps);
return -1;
}
return 0;
}
/** Send a success message with MPPE-keys
*
* The only work to be done is the add the appropriate SEND/RECV
* attributes derived from the MSK.
*/
static int eap_aka_send_eap_success(eap_session_t *eap_session)
{
REQUEST *request = eap_session->request;
uint8_t *p;
eap_aka_session_t *eap_aka_session;
RDEBUG2("Sending EAP-Success");
eap_session->this_round->request->code = FR_EAP_CODE_SUCCESS;
eap_session->finished = true;
eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
p = eap_aka_session->keys.msk;
eap_add_reply(eap_session->request, "MS-MPPE-Recv-Key", p, EAP_TLS_MPPE_KEY_LEN);
p += EAP_TLS_MPPE_KEY_LEN;
eap_add_reply(eap_session->request, "MS-MPPE-Send-Key", p, EAP_TLS_MPPE_KEY_LEN);
return 0;
}
/** Send a failure message
*
*/
static int eap_aka_send_eap_failure_notification(eap_session_t *eap_session)
{
REQUEST *request = eap_session->request;
RADIUS_PACKET *packet = eap_session->request->reply;
fr_cursor_t cursor;
VALUE_PAIR *vp;
eap_aka_session_t *eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
fr_cursor_init(&cursor, &packet->vps);
vp = fr_pair_find_by_child_num(packet->vps, dict_sim_root, FR_EAP_AKA_NOTIFICATION, TAG_ANY);
if (!vp) {
vp = fr_pair_afrom_child_num(packet, dict_sim_root, FR_EAP_AKA_NOTIFICATION);
vp->vp_uint16 = FR_EAP_AKA_NOTIFICATION_VALUE_GENERAL_FAILURE;
fr_cursor_append(&cursor, vp);
}
/*
* Change the failure notification depending where
* we are in the state machine.
*/
if (eap_aka_session->challenge_success) {
vp->vp_uint16 &= ~0x4000; /* Unset phase bit */
} else {
vp->vp_uint16 |= 0x4000; /* Set phase bit */
}
vp->vp_uint16 &= ~0x8000; /* In both cases success bit should be low */
RDEBUG2("Sending AKA-Notification (%pV)", &vp->data);
eap_session->this_round->request->code = FR_EAP_CODE_REQUEST;
/*
* Set the subtype to notification
*/
vp = fr_pair_afrom_child_num(packet, dict_aka_root, FR_EAP_AKA_SUBTYPE);
vp->vp_uint16 = FR_EAP_AKA_SUBTYPE_VALUE_AKA_NOTIFICATION;
fr_cursor_append(&cursor, vp);
/*
* If we're after the challenge phase
* then we need to include a MAC to
* protect notifications.
*/
if (eap_aka_session->challenge_success) {
vp = fr_pair_afrom_child_num(packet, dict_sim_root, FR_EAP_AKA_MAC);
fr_pair_replace(&packet->vps, vp);
}
/*
* Encode the packet
*/
if (eap_aka_compose(eap_session) < 0) {
fr_pair_list_free(&packet->vps);
return -1;
}
return 0;
}
static int eap_aka_send_eap_failure(eap_session_t *eap_session)
{
REQUEST *request = eap_session->request;
RDEBUG2("Sending EAP-Failure");
eap_session->this_round->request->code = FR_EAP_CODE_FAILURE;
eap_session->finished = true;
return 0;
}
/** Run the server state machine
*
*/
static void eap_aka_state_enter(eap_session_t *eap_session, eap_aka_server_state_t new_state)
{
REQUEST *request = eap_session->request;
eap_aka_session_t *eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
if (new_state != eap_aka_session->state) {
RDEBUG2("Changed state %s -> %s",
fr_int2str(aka_state_table, eap_aka_session->state, "<unknown>"),
fr_int2str(aka_state_table, new_state, "<unknown>"));
eap_aka_session->state = new_state;
} else {
RDEBUG2("Reentering state %s",
fr_int2str(aka_state_table, eap_aka_session->state, "<unknown>"));
}
switch (new_state) {
/*
* Send an EAP-AKA Identity request
*/
case EAP_AKA_SERVER_IDENTITY:
if (eap_aka_send_identity_request(eap_session) < 0) {
notify_failure:
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
return;
}
break;
/*
* Send the EAP-AKA Challenge message.
*/
case EAP_AKA_SERVER_CHALLENGE:
if (eap_aka_send_challenge(eap_session) < 0) goto notify_failure;
break;
/*
* Sent a protected success notification
*/
case EAP_AKA_SERVER_SUCCESS_NOTIFICATION:
if (eap_aka_send_eap_success_notification(eap_session) < 0) goto notify_failure;
break;
/*
* Send the EAP Success message (we're done)
*/
case EAP_AKA_SERVER_SUCCESS:
if (eap_aka_send_eap_success(eap_session) < 0) goto notify_failure;
return;
/*
* Send a general failure notification
*/
case EAP_AKA_SERVER_FAILURE_NOTIFICATION:
if (eap_aka_send_eap_failure_notification(eap_session) < 0) { /* Fallback to EAP-Failure */
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE);
}
return;
/*
* Send an EAP-Failure (we're done)
*/
case EAP_AKA_SERVER_FAILURE:
eap_aka_send_eap_failure(eap_session);
return;
default:
rad_assert(0); /* Invalid transition */
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
return;
}
}
static int process_eap_aka_identity(eap_session_t *eap_session, VALUE_PAIR *vps)
{
REQUEST *request = eap_session->request;
eap_aka_session_t *eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
VALUE_PAIR *id;
fr_sim_id_type_t type = SIM_ID_TYPE_UNKNOWN;
fr_sim_method_hint_t method = SIM_METHOD_HINT_UNKNOWN;
/*
* Digest the identity response
*/
if (fr_sim_crypto_update_checkcode(eap_aka_session->checkcode_state, eap_session->this_round->response) < 0) {
RPEDEBUG("Failed updating checkcode");
return -1;
}
/*
* See if we got an AT_IDENTITY
*/
id = fr_pair_find_by_child_num(vps, dict_aka_root, FR_EAP_AKA_IDENTITY, TAG_ANY);
if (id) {
if (fr_sim_id_type(&type, &method,
eap_session->identity, talloc_array_length(eap_session->identity) - 1) < 0) {
RWDEBUG2("Failed parsing identity: %s", fr_strerror());
}
/*
* Update cryptographic identity
*/
talloc_const_free(eap_aka_session->keys.identity);
eap_aka_session->keys.identity_len = id->vp_length;
MEM(eap_aka_session->keys.identity = talloc_memdup(eap_aka_session, id->vp_strvalue, id->vp_length));
}
/*
* @TODO Run a virtual server to see if we can use the
* identity we just acquired, or whether we need to
* negotiate the next permissive ID.
*/
/*
* Negotiate the next permissive form
* if identity, or fail.
*/
switch (eap_aka_session->id_req) {
case SIM_ANY_ID_REQ:
eap_aka_session->id_req = SIM_FULLAUTH_ID_REQ;
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_IDENTITY);
break;
case SIM_FULLAUTH_ID_REQ:
eap_aka_session->id_req = SIM_PERMANENT_ID_REQ;
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_IDENTITY);
break;
case SIM_PERMANENT_ID_REQ:
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_CHALLENGE);
// REDEBUG2("Failed to negotiate a usable identity");
// eap_aka_state_enter(eap_session, eap_aka_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
break;
case SIM_NO_ID_REQ:
rad_assert(0);
return -1;
}
return 0;
}
/** Process an EAP-AKA/Response/Challenge
*
* Verify that MAC, and RES match what we expect.
*/
static int process_eap_aka_challenge(eap_session_t *eap_session, VALUE_PAIR *vps)
{
REQUEST *request = eap_session->request;
eap_aka_session_t *eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
uint8_t calc_mac[SIM_MAC_DIGEST_SIZE];
ssize_t slen;
VALUE_PAIR *vp = NULL, *mac, *checkcode;
mac = fr_pair_find_by_child_num(vps, dict_aka_root, FR_EAP_AKA_MAC, TAG_ANY);
if (!mac) {
REDEBUG("Missing AT_MAC attribute");
return -1;
}
if (mac->vp_length != SIM_MAC_DIGEST_SIZE) {
REDEBUG("EAP-AKA-MAC has incorrect length, expected %u bytes got %zu bytes",
SIM_MAC_DIGEST_SIZE, mac->vp_length);
return -1;
}
slen = fr_sim_crypto_sign_packet(calc_mac, eap_session->this_round->response, true,
eap_aka_session->mac_md,
eap_aka_session->keys.k_aut, eap_aka_session->keys.k_aut_len,
NULL, 0);
if (slen < 0) {
RPEDEBUG("Failed calculating MAC");
return -1;
} else if (slen == 0) {
REDEBUG("Missing EAP-AKA-MAC attribute in packet buffer");
return -1;
}
if (memcmp(mac->vp_octets, calc_mac, sizeof(calc_mac)) == 0) {
RDEBUG2("EAP-AKA-MAC matches calculated MAC");
} else {
REDEBUG("EAP-AKA-MAC does not match calculated MAC");
RHEXDUMP_INLINE(L_DBG_LVL_2, mac->vp_octets, SIM_MAC_DIGEST_SIZE, "Received");
RHEXDUMP_INLINE(L_DBG_LVL_2, calc_mac, SIM_MAC_DIGEST_SIZE, "Expected");
return -1;
}
/*
* If the peer doesn't include a checkcode then that
* means they don't support it, and we can't validate
* their view of the identity packets.
*/
checkcode = fr_pair_find_by_child_num(vps, dict_aka_root, FR_EAP_AKA_CHECKCODE, TAG_ANY);
if (checkcode) {
if (checkcode->vp_length != eap_aka_session->checkcode_len) {
REDEBUG("Checkcode length (%zu) does not match calculated checkcode length (%zu)",
checkcode->vp_length, eap_aka_session->checkcode_len);
return -1;
}
if (memcmp(checkcode->vp_octets, eap_aka_session->checkcode, eap_aka_session->checkcode_len) == 0) {
RDEBUG("EAP-AKA-Checkcode matches calculated checkcode");
} else {
REDEBUG("EAP-AKA-Checkcode does not match calculated checkcode");
RHEXDUMP_INLINE(L_DBG_LVL_2, checkcode->vp_octets, checkcode->vp_length, "Received");
RHEXDUMP_INLINE(L_DBG_LVL_2, eap_aka_session->checkcode,
eap_aka_session->checkcode_len, "Expected");
return -1;
}
/*
* Only print something if we calculated a checkcode
*/
} else if (eap_aka_session->checkcode_len > 0){
RDEBUG2("Peer didn't include EAP-AKA-Checkcode, skipping checkcode validation");
}
vp = fr_pair_find_by_child_num(vps, dict_aka_root, FR_EAP_AKA_RES, TAG_ANY);
if (!vp) {
REDEBUG("Missing EAP-AKA-RES from challenge response");
return -1;
}
if (vp->vp_length != eap_aka_session->keys.umts.vector.xres_len) {
REDEBUG("EAP-AKA-RES length (%zu) does not match XRES length (%zu)",
vp->vp_length, eap_aka_session->keys.umts.vector.xres_len);
return -1;
}
if (memcmp(vp->vp_octets, eap_aka_session->keys.umts.vector.xres, vp->vp_length)) {
REDEBUG("EAP-AKA-RES from client does match XRES");
RHEXDUMP_INLINE(L_DBG_LVL_2, vp->vp_octets, vp->vp_length, "RES :");
RHEXDUMP_INLINE(L_DBG_LVL_2, eap_aka_session->keys.umts.vector.xres,
eap_aka_session->keys.umts.vector.xres_len, "XRES :");
return -1;
}
RDEBUG2("EAP-AKA-RES matches XRES");
eap_aka_session->challenge_success = true;
/*
* If the peer wants a Success notification, then
* send a success notification, otherwise send a
* normal EAP-Success.
*/
if (fr_pair_find_by_child_num(vps, dict_aka_root, FR_EAP_AKA_RESULT_IND, TAG_ANY)) {
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_SUCCESS_NOTIFICATION);
} else {
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_SUCCESS);
}
return 0;
}
/** Process the Peer's response and advantage the state machine
*
*/
static rlm_rcode_t mod_process(UNUSED void *arg, eap_session_t *eap_session)
{
REQUEST *request = eap_session->request;
eap_aka_session_t *eap_aka_session = talloc_get_type_abort(eap_session->opaque, eap_aka_session_t);
fr_sim_decode_ctx_t ctx = {
.keys = &eap_aka_session->keys,
.root = dict_aka_root
};
VALUE_PAIR *vp, *vps, *subtype_vp;
vp_cursor_t cursor;
eap_aka_subtype_t subtype;
int ret;
/*
* RFC 4187 says we ignore the contents of the
* next packet after we send our success notification
* and always send a success.
*/
if (eap_aka_session->state == EAP_AKA_SERVER_SUCCESS_NOTIFICATION) {
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_SUCCESS);
return RLM_MODULE_HANDLED;
}
/* vps is the data from the client */
vps = request->packet->vps;
fr_pair_cursor_init(&cursor, &request->packet->vps);
fr_pair_cursor_last(&cursor);
ret = fr_sim_decode(eap_session->request,
&cursor,
eap_session->this_round->response->type.data,
eap_session->this_round->response->type.length,
&ctx);
/*
* RFC 4187 says we *MUST* notify, not just
* send an EAP-Failure in this case where
* we cannot decode an EAP-AKA packet.
*/
if (ret < 0) {
RPEDEBUG2("Failed decoding EAP-AKA attributes");
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
return RLM_MODULE_HANDLED; /* We need to process more packets */
}
vp = fr_pair_cursor_current(&cursor);
if (vp && RDEBUG_ENABLED2) {
RDEBUG2("EAP-AKA decoded attributes");
rdebug_pair_list(L_DBG_LVL_2, request, vp, NULL);
}
subtype_vp = fr_pair_find_by_child_num(vps, dict_aka_root, FR_EAP_AKA_SUBTYPE, TAG_ANY);
if (!subtype_vp) {
REDEBUG("Missing EAP-AKA-Subtype");
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
return RLM_MODULE_HANDLED; /* We need to process more packets */
}
subtype = subtype_vp->vp_uint16;
switch (eap_aka_session->state) {
/*
* Here we expected the peer to send
* us identities for validation.
*/
case EAP_AKA_SERVER_IDENTITY:
switch (subtype) {
case EAP_AKA_IDENTITY:
if (process_eap_aka_identity(eap_session, vps) == 0) return RLM_MODULE_HANDLED;
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
return RLM_MODULE_HANDLED; /* We need to process more packets */
/*
* Case 1 where we're allowed to send an EAP-Failure
*
* This can happen in the case of a conservative
* peer, where it refuses to provide the permanent
* identity.
*/
case EAP_AKA_CLIENT_ERROR:
{
char buff[20];
vp = fr_pair_find_by_child_num(vps, dict_aka_root, FR_EAP_AKA_CLIENT_ERROR_CODE, TAG_ANY);
if (!vp) {
REDEBUG("EAP-AKA Peer rejected AKA-Identity (%s) with client-error message but "
"has not supplied a client error code",
fr_int2str(sim_id_request_table, eap_aka_session->id_req, "<INVALID>"));
} else {
REDEBUG("Client rejected AKA-Identity (%s) with error: %s (%i)",
fr_int2str(sim_id_request_table, eap_aka_session->id_req, "<INVALID>"),
fr_pair_value_enum(vp, buff), vp->vp_uint16);
}
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE);
return RLM_MODULE_REJECT;
}
case EAP_AKA_NOTIFICATION:
notification:
{
char buff[20];
vp = fr_pair_afrom_child_num(vps, dict_aka_root, FR_EAP_AKA_NOTIFICATION);
if (!vp) {
REDEBUG2("Received AKA-Notification with no notification code");
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
return RLM_MODULE_HANDLED; /* We need to process more packets */
}
/*
* Case 3 where we're allowed to send an EAP-Failure
*/
if (!(vp->vp_uint16 & 0x8000)) {
REDEBUG2("AKA-Notification %s (%i) indicates failure", fr_pair_value_enum(vp, buff),
vp->vp_uint16);
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE);
return RLM_MODULE_REJECT;
}
/*
* ...if it's not a failure, then re-enter the
* current state.
*/
REDEBUG2("Got AKA-Notification %s (%i)", fr_pair_value_enum(vp, buff), vp->vp_uint16);
eap_aka_state_enter(eap_session, eap_aka_session->state);
return RLM_MODULE_HANDLED;
}
default:
unexpected_subtype:
/*
* RFC 4187 says we *MUST* notify, not just
* send an EAP-Failure in this case.
*/
REDEBUG("Unexpected subtype %pV", &subtype_vp->data);
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
return RLM_MODULE_HANDLED; /* We need to process more packets */
}
break;
/*
* Process the response to our previous challenge.
*/
case EAP_AKA_SERVER_CHALLENGE:
switch (subtype) {
case EAP_AKA_CHALLENGE:
if (process_eap_aka_challenge(eap_session, vps) == 0) return RLM_MODULE_HANDLED;
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
return RLM_MODULE_HANDLED; /* We need to process more packets */
case EAP_AKA_SYNCHRONIZATION_FAILURE:
REDEBUG("EAP-AKA Peer synchronization failure"); /* We can't handle these yet */
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE_NOTIFICATION);
return RLM_MODULE_HANDLED; /* We need to process more packets */
/*
* Case 1 where we're allowed to send an EAP-Failure
*/
case EAP_AKA_CLIENT_ERROR:
{
char buff[20];
vp = fr_pair_find_by_child_num(vps, dict_aka_root, FR_EAP_AKA_CLIENT_ERROR_CODE, TAG_ANY);
if (!vp) {
REDEBUG("EAP-AKA Peer rejected AKA-Challenge with client-error message but "
"has not supplied a client error code");
} else {
REDEBUG("Client rejected AKA-Challenge with error: %s (%i)",
fr_pair_value_enum(vp, buff), vp->vp_uint16);
}
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE);
return RLM_MODULE_REJECT;
}
/*
* Case 2 where we're allowed to send an EAP-Failure
*/
case EAP_AKA_AUTHENTICATION_REJECT:
REDEBUG("EAP-AKA Peer Rejected AUTN");
eap_aka_state_enter(eap_session, EAP_AKA_SERVER_FAILURE);
return RLM_MODULE_REJECT;
case EAP_AKA_NOTIFICATION:
goto notification;
default:
goto unexpected_subtype;
}
/*
* Peer acked our failure
*/