/** Decode SIM/AKA/AKA' attributes
*
* @param[in] ctx to allocate attributes in.
* @param[in] cursor where to insert the attributes.
* @param[in] dict for looking up attributes.
* @param[in] data data to parse.
* @param[in] data_len length of data. For top level attributes packet_ctx must be the length
* of the packet (so we can hunt for AT_IV), for Sub-TLVs it should
* be the length of the container value.
* @param[in] decoder_ctx extra context to pass to the decoder.
* @return
* - The number of bytes parsed.
* - -1 on error.
*/
ssize_t fr_sim_decode_pair(TALLOC_CTX *ctx, fr_cursor_t *cursor, fr_dict_t const *dict,
uint8_t const *data, size_t data_len, void *decoder_ctx)
{
return sim_decode_pair_internal(ctx, cursor, fr_dict_root(dict), data, data_len, decoder_ctx);
}
/*
* build a reply to be sent.
*/
static int eap_sim_compose(eap_session_t *eap_session, uint8_t const *hmac_extra, size_t hmac_extra_len)
{
eap_sim_session_t *eap_sim_session = talloc_get_type_abort(eap_session->opaque, eap_sim_session_t);
fr_cursor_t cursor;
fr_cursor_t to_encode;
VALUE_PAIR *head = NULL, *vp;
REQUEST *request = eap_session->request;
fr_sim_encode_ctx_t encoder_ctx = {
.root = fr_dict_root(dict_eap_sim),
.keys = &eap_sim_session->keys,
.iv = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
.iv_included = false,
.hmac_md = EVP_sha1(),
.eap_packet = eap_session->this_round->request,
.hmac_extra = hmac_extra,
.hmac_extra_len = hmac_extra_len
};
ssize_t ret;
/* we will set the ID on requests, since we have to HMAC it */
eap_session->this_round->set_request_id = true;
fr_cursor_init(&cursor, &eap_session->request->reply->vps);
fr_cursor_init(&to_encode, &head);
while ((vp = fr_cursor_current(&cursor))) {
if (!fr_dict_parent_common(fr_dict_root(dict_eap_sim), vp->da, true)) {
fr_cursor_next(&cursor);
continue;
}
vp = fr_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_sim_session->allow_encrypted && fr_dict_parent_common(attr_eap_sim_encr_data, vp->da, true)) {
RWDEBUG("Silently discarding &reply:%s: Encrypted attributes not allowed in this round",
vp->da->name);
talloc_free(vp);
continue;
}
fr_cursor_append(&to_encode, vp);
}
RDEBUG2("Encoding EAP-SIM attributes");
log_request_pair_list(L_DBG_LVL_2, request, head, NULL);
eap_session->this_round->request->type.num = FR_EAP_SIM;
eap_session->this_round->request->id = eap_sim_session->sim_id++ & 0xff;
eap_session->this_round->set_request_id = true;
ret = fr_sim_encode(eap_session->request, head, &encoder_ctx);
fr_cursor_head(&to_encode);
fr_cursor_free_list(&to_encode);
if (ret < 0) {
RPEDEBUG("Failed encoding EAP-SIM data");
return -1;
}
return 0;
}
static int eap_sim_send_start(eap_session_t *eap_session)
{
REQUEST *request = eap_session->request;
VALUE_PAIR **vps, *vp;
uint16_t version;
eap_sim_session_t *eap_sim_session = talloc_get_type_abort(eap_session->opaque, eap_sim_session_t);
RADIUS_PACKET *packet;
rad_assert(eap_session->request != NULL);
rad_assert(eap_session->request->reply);
RDEBUG2("Sending SIM-State");
eap_session->this_round->request->code = FR_EAP_CODE_REQUEST;
eap_sim_session->allow_encrypted = false; /* In case this is after failed fast-resumption */
/* these are the outgoing attributes */
packet = eap_session->request->reply;
vps = &packet->vps;
rad_assert(vps != NULL);
/*
* Add appropriate TLVs for the EAP things we wish to send.
*/
vp = fr_pair_afrom_da(packet, attr_eap_sim_version_list);
vp->vp_uint16 = EAP_SIM_VERSION;
fr_pair_add(vps, vp);
/* record it in the ess */
version = htons(EAP_SIM_VERSION);
memcpy(eap_sim_session->keys.gsm.version_list, &version, sizeof(version));
eap_sim_session->keys.gsm.version_list_len = 2;
/*
* Select the right type of identity request attribute
*/
switch (eap_sim_session->id_req) {
case SIM_ANY_ID_REQ:
vp = fr_pair_afrom_da(packet, attr_eap_sim_any_id_req);
break;
case SIM_PERMANENT_ID_REQ:
vp = fr_pair_afrom_da(packet, attr_eap_sim_permanent_id_req);
break;
case SIM_FULLAUTH_ID_REQ:
vp = fr_pair_afrom_da(packet, attr_eap_sim_fullauth_id_req);
break;
default:
rad_assert(0);
}
vp->vp_bool = true;
fr_pair_replace(vps, vp);
/* the SUBTYPE, set to start. */
vp = fr_pair_afrom_da(packet, attr_eap_sim_subtype);
vp->vp_uint16 = EAP_SIM_START;
fr_pair_replace(vps, vp);
/*
* Encode the packet
*/
if (eap_sim_compose(eap_session, NULL, 0) < 0) {
fr_pair_list_free(&packet->vps);
return -1;
}
return 0;
}
