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* hostapd / EAP-PAX (RFC 4746) server
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* Copyright (c) 2005-2007, Jouni Malinen <j@w1.fi>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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* Alternatively, this software may be distributed under the terms of BSD
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* See README and COPYING for more details.
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#include "eap_server/eap_i.h"
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#include "eap_common/eap_pax_common.h"
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* Note: only PAX_STD subprotocol is currently supported
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* TODO: Add support with PAX_SEC with the mandatory to implement ciphersuite
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* (HMAC_SHA1_128, IANA DH Group 14 (2048 bits), RSA-PKCS1-V1_5) and
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* recommended ciphersuite (HMAC_SHA256_128, IANA DH Group 15 (3072 bits),
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enum { PAX_STD_1, PAX_STD_3, SUCCESS, FAILURE } state;
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u8 e[2 * EAP_PAX_RAND_LEN];
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u8 x[EAP_PAX_RAND_LEN]; /* server rand */
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u8 y[EAP_PAX_RAND_LEN]; /* client rand */
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u8 ak[EAP_PAX_AK_LEN];
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u8 mk[EAP_PAX_MK_LEN];
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u8 ck[EAP_PAX_CK_LEN];
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u8 ick[EAP_PAX_ICK_LEN];
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static void * eap_pax_init(struct eap_sm *sm)
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struct eap_pax_data *data;
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data = os_zalloc(sizeof(*data));
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data->state = PAX_STD_1;
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* TODO: make this configurable once EAP_PAX_HMAC_SHA256_128 is
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data->mac_id = EAP_PAX_MAC_HMAC_SHA1_128;
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static void eap_pax_reset(struct eap_sm *sm, void *priv)
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struct eap_pax_data *data = priv;
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static struct wpabuf * eap_pax_build_std_1(struct eap_sm *sm,
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struct eap_pax_data *data, u8 id)
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struct eap_pax_hdr *pax;
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wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-1 (sending)");
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if (os_get_random(data->rand.r.x, EAP_PAX_RAND_LEN)) {
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wpa_printf(MSG_ERROR, "EAP-PAX: Failed to get random data");
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data->state = FAILURE;
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req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX,
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sizeof(*pax) + 2 + EAP_PAX_RAND_LEN +
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EAP_PAX_ICV_LEN, EAP_CODE_REQUEST, id);
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wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory "
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data->state = FAILURE;
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pax = wpabuf_put(req, sizeof(*pax));
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pax->op_code = EAP_PAX_OP_STD_1;
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pax->mac_id = data->mac_id;
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pax->dh_group_id = EAP_PAX_DH_GROUP_NONE;
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pax->public_key_id = EAP_PAX_PUBLIC_KEY_NONE;
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wpabuf_put_be16(req, EAP_PAX_RAND_LEN);
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wpabuf_put_data(req, data->rand.r.x, EAP_PAX_RAND_LEN);
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: A = X (server rand)",
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data->rand.r.x, EAP_PAX_RAND_LEN);
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pos = wpabuf_put(req, EAP_PAX_MAC_LEN);
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eap_pax_mac(data->mac_id, (u8 *) "", 0,
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wpabuf_mhead(req), wpabuf_len(req) - EAP_PAX_ICV_LEN,
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NULL, 0, NULL, 0, pos);
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
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static struct wpabuf * eap_pax_build_std_3(struct eap_sm *sm,
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struct eap_pax_data *data, u8 id)
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struct eap_pax_hdr *pax;
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wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-3 (sending)");
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req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX,
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sizeof(*pax) + 2 + EAP_PAX_MAC_LEN +
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EAP_PAX_ICV_LEN, EAP_CODE_REQUEST, id);
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wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory "
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data->state = FAILURE;
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pax = wpabuf_put(req, sizeof(*pax));
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pax->op_code = EAP_PAX_OP_STD_3;
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pax->mac_id = data->mac_id;
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pax->dh_group_id = EAP_PAX_DH_GROUP_NONE;
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pax->public_key_id = EAP_PAX_PUBLIC_KEY_NONE;
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wpabuf_put_be16(req, EAP_PAX_MAC_LEN);
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pos = wpabuf_put(req, EAP_PAX_MAC_LEN);
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eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
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data->rand.r.y, EAP_PAX_RAND_LEN,
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(u8 *) data->cid, data->cid_len, NULL, 0, pos);
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(B, CID)",
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pos, EAP_PAX_MAC_LEN);
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pos += EAP_PAX_MAC_LEN;
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/* Optional ADE could be added here, if needed */
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pos = wpabuf_put(req, EAP_PAX_MAC_LEN);
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eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
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wpabuf_mhead(req), wpabuf_len(req) - EAP_PAX_ICV_LEN,
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NULL, 0, NULL, 0, pos);
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
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static struct wpabuf * eap_pax_buildReq(struct eap_sm *sm, void *priv, u8 id)
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struct eap_pax_data *data = priv;
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switch (data->state) {
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return eap_pax_build_std_1(sm, data, id);
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return eap_pax_build_std_3(sm, data, id);
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wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown state %d in buildReq",
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static Boolean eap_pax_check(struct eap_sm *sm, void *priv,
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struct wpabuf *respData)
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struct eap_pax_data *data = priv;
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struct eap_pax_hdr *resp;
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u8 icvbuf[EAP_PAX_ICV_LEN], *icv;
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pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
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if (pos == NULL || len < sizeof(*resp)) {
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wpa_printf(MSG_INFO, "EAP-PAX: Invalid frame");
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mlen = sizeof(struct eap_hdr) + 1 + len;
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resp = (struct eap_pax_hdr *) pos;
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wpa_printf(MSG_DEBUG, "EAP-PAX: received frame: op_code 0x%x "
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"flags 0x%x mac_id 0x%x dh_group_id 0x%x "
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"public_key_id 0x%x",
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resp->op_code, resp->flags, resp->mac_id, resp->dh_group_id,
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resp->public_key_id);
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: received payload",
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(u8 *) (resp + 1), len - sizeof(*resp) - EAP_PAX_ICV_LEN);
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if (data->state == PAX_STD_1 &&
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resp->op_code != EAP_PAX_OP_STD_2) {
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wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX_STD-2 - "
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"ignore op %d", resp->op_code);
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if (data->state == PAX_STD_3 &&
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resp->op_code != EAP_PAX_OP_ACK) {
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wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX-ACK - "
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"ignore op %d", resp->op_code);
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if (resp->op_code != EAP_PAX_OP_STD_2 &&
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resp->op_code != EAP_PAX_OP_ACK) {
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wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown op_code 0x%x",
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if (data->mac_id != resp->mac_id) {
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wpa_printf(MSG_DEBUG, "EAP-PAX: Expected MAC ID 0x%x, "
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"received 0x%x", data->mac_id, resp->mac_id);
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if (resp->dh_group_id != EAP_PAX_DH_GROUP_NONE) {
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wpa_printf(MSG_INFO, "EAP-PAX: Expected DH Group ID 0x%x, "
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"received 0x%x", EAP_PAX_DH_GROUP_NONE,
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if (resp->public_key_id != EAP_PAX_PUBLIC_KEY_NONE) {
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wpa_printf(MSG_INFO, "EAP-PAX: Expected Public Key ID 0x%x, "
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"received 0x%x", EAP_PAX_PUBLIC_KEY_NONE,
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resp->public_key_id);
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if (resp->flags & EAP_PAX_FLAGS_MF) {
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/* TODO: add support for reassembling fragments */
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wpa_printf(MSG_INFO, "EAP-PAX: fragmentation not supported");
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if (resp->flags & EAP_PAX_FLAGS_CE) {
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wpa_printf(MSG_INFO, "EAP-PAX: Unexpected CE flag");
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if (data->keys_set) {
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if (len - sizeof(*resp) < EAP_PAX_ICV_LEN) {
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wpa_printf(MSG_INFO, "EAP-PAX: No ICV in the packet");
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icv = wpabuf_mhead_u8(respData) + mlen - EAP_PAX_ICV_LEN;
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", icv, EAP_PAX_ICV_LEN);
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eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
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wpabuf_mhead(respData),
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wpabuf_len(respData) - EAP_PAX_ICV_LEN,
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NULL, 0, NULL, 0, icvbuf);
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if (os_memcmp(icvbuf, icv, EAP_PAX_ICV_LEN) != 0) {
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wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV");
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV",
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icvbuf, EAP_PAX_ICV_LEN);
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static void eap_pax_process_std_2(struct eap_sm *sm,
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struct eap_pax_data *data,
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struct wpabuf *respData)
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struct eap_pax_hdr *resp;
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u8 mac[EAP_PAX_MAC_LEN], icvbuf[EAP_PAX_ICV_LEN];
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if (data->state != PAX_STD_1)
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wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX_STD-2");
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pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
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if (pos == NULL || len < sizeof(*resp) + EAP_PAX_ICV_LEN)
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resp = (struct eap_pax_hdr *) pos;
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pos = (u8 *) (resp + 1);
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left = len - sizeof(*resp);
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if (left < 2 + EAP_PAX_RAND_LEN ||
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WPA_GET_BE16(pos) != EAP_PAX_RAND_LEN) {
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wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (B)");
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os_memcpy(data->rand.r.y, pos, EAP_PAX_RAND_LEN);
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Y (client rand)",
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data->rand.r.y, EAP_PAX_RAND_LEN);
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pos += EAP_PAX_RAND_LEN;
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left -= EAP_PAX_RAND_LEN;
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if (left < 2 || (size_t) 2 + WPA_GET_BE16(pos) > left) {
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wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (CID)");
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data->cid_len = WPA_GET_BE16(pos);
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data->cid = os_malloc(data->cid_len);
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if (data->cid == NULL) {
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wpa_printf(MSG_INFO, "EAP-PAX: Failed to allocate memory for "
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os_memcpy(data->cid, pos + 2, data->cid_len);
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pos += 2 + data->cid_len;
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left -= 2 + data->cid_len;
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wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PAX: CID",
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(u8 *) data->cid, data->cid_len);
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if (left < 2 + EAP_PAX_MAC_LEN ||
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WPA_GET_BE16(pos) != EAP_PAX_MAC_LEN) {
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wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (MAC_CK)");
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(A, B, CID)",
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pos, EAP_PAX_MAC_LEN);
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if (eap_user_get(sm, (u8 *) data->cid, data->cid_len, 0) < 0) {
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wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: unknown CID",
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(u8 *) data->cid, data->cid_len);
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data->state = FAILURE;
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i < EAP_MAX_METHODS &&
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(sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
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sm->user->methods[i].method != EAP_TYPE_NONE);
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if (sm->user->methods[i].vendor == EAP_VENDOR_IETF &&
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sm->user->methods[i].method == EAP_TYPE_PAX)
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if (i >= EAP_MAX_METHODS ||
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sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
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sm->user->methods[i].method != EAP_TYPE_PAX) {
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wpa_hexdump_ascii(MSG_DEBUG,
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"EAP-PAX: EAP-PAX not enabled for CID",
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(u8 *) data->cid, data->cid_len);
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data->state = FAILURE;
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if (sm->user->password == NULL ||
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sm->user->password_len != EAP_PAX_AK_LEN) {
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wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: invalid password in "
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"user database for CID",
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(u8 *) data->cid, data->cid_len);
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data->state = FAILURE;
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os_memcpy(data->ak, sm->user->password, EAP_PAX_AK_LEN);
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if (eap_pax_initial_key_derivation(data->mac_id, data->ak,
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data->rand.e, data->mk, data->ck,
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wpa_printf(MSG_INFO, "EAP-PAX: Failed to complete initial "
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data->state = FAILURE;
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eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
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data->rand.r.x, EAP_PAX_RAND_LEN,
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data->rand.r.y, EAP_PAX_RAND_LEN,
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(u8 *) data->cid, data->cid_len, mac);
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if (os_memcmp(mac, pos, EAP_PAX_MAC_LEN) != 0) {
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wpa_printf(MSG_INFO, "EAP-PAX: Invalid MAC_CK(A, B, CID) in "
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected MAC_CK(A, B, CID)",
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mac, EAP_PAX_MAC_LEN);
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data->state = FAILURE;
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pos += EAP_PAX_MAC_LEN;
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left -= EAP_PAX_MAC_LEN;
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if (left < EAP_PAX_ICV_LEN) {
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wpa_printf(MSG_INFO, "EAP-PAX: Too short ICV (%lu) in "
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"PAX_STD-2", (unsigned long) left);
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
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eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
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wpabuf_head(respData),
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wpabuf_len(respData) - EAP_PAX_ICV_LEN, NULL, 0, NULL, 0,
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if (os_memcmp(icvbuf, pos, EAP_PAX_ICV_LEN) != 0) {
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wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV in PAX_STD-2");
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV",
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icvbuf, EAP_PAX_ICV_LEN);
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pos += EAP_PAX_ICV_LEN;
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left -= EAP_PAX_ICV_LEN;
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wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
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data->state = PAX_STD_3;
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static void eap_pax_process_ack(struct eap_sm *sm,
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struct eap_pax_data *data,
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struct wpabuf *respData)
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if (data->state != PAX_STD_3)
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wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX-ACK - authentication "
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"completed successfully");
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data->state = SUCCESS;
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static void eap_pax_process(struct eap_sm *sm, void *priv,
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struct wpabuf *respData)
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struct eap_pax_data *data = priv;
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struct eap_pax_hdr *resp;
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if (sm->user == NULL || sm->user->password == NULL) {
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wpa_printf(MSG_INFO, "EAP-PAX: Plaintext password not "
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data->state = FAILURE;
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pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
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if (pos == NULL || len < sizeof(*resp))
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resp = (struct eap_pax_hdr *) pos;
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switch (resp->op_code) {
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case EAP_PAX_OP_STD_2:
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eap_pax_process_std_2(sm, data, respData);
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eap_pax_process_ack(sm, data, respData);
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static Boolean eap_pax_isDone(struct eap_sm *sm, void *priv)
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struct eap_pax_data *data = priv;
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return data->state == SUCCESS || data->state == FAILURE;
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static u8 * eap_pax_getKey(struct eap_sm *sm, void *priv, size_t *len)
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struct eap_pax_data *data = priv;
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if (data->state != SUCCESS)
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key = os_malloc(EAP_MSK_LEN);
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eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
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"Master Session Key", data->rand.e, 2 * EAP_PAX_RAND_LEN,
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static u8 * eap_pax_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
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struct eap_pax_data *data = priv;
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if (data->state != SUCCESS)
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key = os_malloc(EAP_EMSK_LEN);
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eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
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"Extended Master Session Key",
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data->rand.e, 2 * EAP_PAX_RAND_LEN,
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static Boolean eap_pax_isSuccess(struct eap_sm *sm, void *priv)
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struct eap_pax_data *data = priv;
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return data->state == SUCCESS;
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int eap_server_pax_register(void)
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struct eap_method *eap;
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eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
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EAP_VENDOR_IETF, EAP_TYPE_PAX, "PAX");
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eap->init = eap_pax_init;
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eap->reset = eap_pax_reset;
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eap->buildReq = eap_pax_buildReq;
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eap->check = eap_pax_check;
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eap->process = eap_pax_process;
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eap->isDone = eap_pax_isDone;
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eap->getKey = eap_pax_getKey;
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eap->isSuccess = eap_pax_isSuccess;
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eap->get_emsk = eap_pax_get_emsk;
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ret = eap_server_method_register(eap);
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eap_server_method_free(eap);