459 lines
11 KiB
C
459 lines
11 KiB
C
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/*
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* hostapd / EAP-PSK (draft-bersani-eap-psk-09.txt) server
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* Copyright (c) 2005, Jouni Malinen <jkmaline@cc.hut.fi>
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*
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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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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*
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* Note: EAP-PSK is an EAP authentication method and as such, completely
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* different from WPA-PSK. This file is not needed for WPA-PSK functionality.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <netinet/in.h>
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#include "hostapd.h"
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#include "common.h"
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#include "eap_i.h"
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#include "aes_wrap.h"
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#include "eap_psk_common.h"
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struct eap_psk_data {
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enum { PSK_1, PSK_3, SUCCESS, FAILURE } state;
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u8 rand_s[EAP_PSK_RAND_LEN];
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u8 rand_p[EAP_PSK_RAND_LEN];
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u8 *id_p, *id_s;
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size_t id_p_len, id_s_len;
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u8 ak[EAP_PSK_AK_LEN], kdk[EAP_PSK_KDK_LEN], tek[EAP_PSK_TEK_LEN];
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u8 msk[EAP_PSK_MSK_LEN];
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};
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static void * eap_psk_init(struct eap_sm *sm)
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{
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struct eap_psk_data *data;
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data = malloc(sizeof(*data));
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if (data == NULL)
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return data;
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memset(data, 0, sizeof(*data));
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data->state = PSK_1;
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data->id_s = "hostapd";
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data->id_s_len = 7;
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return data;
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}
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static void eap_psk_reset(struct eap_sm *sm, void *priv)
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{
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struct eap_psk_data *data = priv;
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free(data->id_p);
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free(data);
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}
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static u8 * eap_psk_build_1(struct eap_sm *sm, struct eap_psk_data *data,
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int id, size_t *reqDataLen)
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{
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struct eap_psk_hdr_1 *req;
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wpa_printf(MSG_DEBUG, "EAP-PSK: PSK-1 (sending)");
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if (hostapd_get_rand(data->rand_s, EAP_PSK_RAND_LEN)) {
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wpa_printf(MSG_ERROR, "EAP-PSK: Failed to get random data");
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data->state = FAILURE;
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return NULL;
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}
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wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: RAND_S (server rand)",
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data->rand_s, EAP_PSK_RAND_LEN);
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*reqDataLen = sizeof(*req) + data->id_s_len;
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req = malloc(*reqDataLen);
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if (req == NULL) {
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wpa_printf(MSG_ERROR, "EAP-PSK: Failed to allocate memory "
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"request");
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data->state = FAILURE;
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return NULL;
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}
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req->code = EAP_CODE_REQUEST;
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req->identifier = id;
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req->length = htons(*reqDataLen);
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req->type = EAP_TYPE_PSK;
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req->flags = 0; /* T=0 */
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memcpy(req->rand_s, data->rand_s, EAP_PSK_RAND_LEN);
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memcpy((u8 *) (req + 1), data->id_s, data->id_s_len);
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return (u8 *) req;
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}
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static u8 * eap_psk_build_3(struct eap_sm *sm, struct eap_psk_data *data,
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int id, size_t *reqDataLen)
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{
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struct eap_psk_hdr_3 *req;
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u8 *buf, *pchannel, nonce[16];
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size_t buflen;
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wpa_printf(MSG_DEBUG, "EAP-PSK: PSK-3 (sending)");
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*reqDataLen = sizeof(*req) + 4 + 16 + 1;
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req = malloc(*reqDataLen);
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if (req == NULL) {
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wpa_printf(MSG_ERROR, "EAP-PSK: Failed to allocate memory "
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"request");
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data->state = FAILURE;
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return NULL;
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}
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req->code = EAP_CODE_REQUEST;
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req->identifier = id;
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req->length = htons(*reqDataLen);
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req->type = EAP_TYPE_PSK;
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req->flags = 2; /* T=2 */
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memcpy(req->rand_s, data->rand_s, EAP_PSK_RAND_LEN);
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/* MAC_S = OMAC1-AES-128(AK, ID_S||RAND_P) */
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buflen = data->id_s_len + EAP_PSK_RAND_LEN;
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buf = malloc(buflen);
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if (buf == NULL) {
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data->state = FAILURE;
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return NULL;
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}
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memcpy(buf, data->id_s, data->id_s_len);
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memcpy(buf + data->id_s_len, data->rand_p, EAP_PSK_RAND_LEN);
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omac1_aes_128(data->ak, buf, buflen, req->mac_s);
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free(buf);
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eap_psk_derive_keys(data->kdk, data->rand_p, data->tek, data->msk);
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wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: TEK", data->tek, EAP_PSK_TEK_LEN);
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wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: MSK", data->msk, EAP_PSK_MSK_LEN);
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memset(nonce, 0, sizeof(nonce));
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pchannel = (u8 *) (req + 1);
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memcpy(pchannel, nonce + 12, 4);
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memset(pchannel + 4, 0, 16); /* Tag */
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pchannel[4 + 16] = EAP_PSK_R_FLAG_DONE_SUCCESS << 6;
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wpa_hexdump(MSG_DEBUG, "EAP-PSK: PCHANNEL (plaintext)",
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pchannel, 4 + 16 + 1);
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aes_128_eax_encrypt(data->tek, nonce, sizeof(nonce), (u8 *) req, 22,
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pchannel + 4 + 16, 1, pchannel + 4);
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wpa_hexdump(MSG_DEBUG, "EAP-PSK: PCHANNEL (encrypted)",
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pchannel, 4 + 16 + 1);
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return (u8 *) req;
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}
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static u8 * eap_psk_buildReq(struct eap_sm *sm, void *priv, int id,
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size_t *reqDataLen)
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{
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struct eap_psk_data *data = priv;
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switch (data->state) {
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case PSK_1:
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return eap_psk_build_1(sm, data, id, reqDataLen);
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case PSK_3:
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return eap_psk_build_3(sm, data, id, reqDataLen);
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default:
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wpa_printf(MSG_DEBUG, "EAP-PSK: Unknown state %d in buildReq",
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data->state);
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break;
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}
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return NULL;
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}
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static Boolean eap_psk_check(struct eap_sm *sm, void *priv,
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u8 *respData, size_t respDataLen)
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{
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struct eap_psk_data *data = priv;
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struct eap_psk_hdr *resp;
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size_t len;
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u8 t;
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resp = (struct eap_psk_hdr *) respData;
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if (respDataLen < sizeof(*resp) || resp->type != EAP_TYPE_PSK ||
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(len = ntohs(resp->length)) > respDataLen ||
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len < sizeof(*resp)) {
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wpa_printf(MSG_INFO, "EAP-PSK: Invalid frame");
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return TRUE;
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}
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t = resp->flags & 0x03;
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wpa_printf(MSG_DEBUG, "EAP-PSK: received frame: T=%d", t);
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if (data->state == PSK_1 && t != 1) {
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wpa_printf(MSG_DEBUG, "EAP-PSK: Expected PSK-2 - "
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"ignore T=%d", t);
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return TRUE;
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}
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if (data->state == PSK_3 && t != 3) {
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wpa_printf(MSG_DEBUG, "EAP-PSK: Expected PSK-4 - "
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"ignore T=%d", t);
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return TRUE;
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}
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if ((t == 1 && len < sizeof(struct eap_psk_hdr_2)) ||
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(t == 3 && len < sizeof(struct eap_psk_hdr_4))) {
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wpa_printf(MSG_DEBUG, "EAP-PSK: Too short frame");
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return TRUE;
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}
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return FALSE;
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}
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static void eap_psk_process_2(struct eap_sm *sm,
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struct eap_psk_data *data,
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u8 *respData, size_t respDataLen)
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{
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struct eap_psk_hdr_2 *resp;
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u8 *pos, mac[EAP_PSK_MAC_LEN], *buf;
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size_t len, left, buflen;
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int i;
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if (data->state != PSK_1)
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return;
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wpa_printf(MSG_DEBUG, "EAP-PSK: Received PSK-2");
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resp = (struct eap_psk_hdr_2 *) respData;
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len = ntohs(resp->length);
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pos = (u8 *) (resp + 1);
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left = len - sizeof(*resp);
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free(data->id_p);
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data->id_p = malloc(left);
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if (data->id_p == NULL) {
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wpa_printf(MSG_INFO, "EAP-PSK: Failed to allocate memory for "
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"ID_P");
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return;
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}
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memcpy(data->id_p, pos, left);
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data->id_p_len = left;
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wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PSK: ID_P",
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data->id_p, data->id_p_len);
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if (eap_user_get(sm, data->id_p, data->id_p_len, 0) < 0) {
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wpa_hexdump_ascii(MSG_DEBUG, "EAP-PSK: unknown ID_P",
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data->id_p, data->id_p_len);
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data->state = FAILURE;
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return;
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}
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for (i = 0;
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i < EAP_MAX_METHODS && sm->user->methods[i] != EAP_TYPE_NONE;
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i++) {
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if (sm->user->methods[i] == EAP_TYPE_PSK)
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break;
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}
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if (sm->user->methods[i] != EAP_TYPE_PSK) {
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wpa_hexdump_ascii(MSG_DEBUG,
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"EAP-PSK: EAP-PSK not enabled for ID_P",
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data->id_p, data->id_p_len);
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data->state = FAILURE;
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return;
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}
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if (sm->user->password == NULL ||
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sm->user->password_len != EAP_PSK_PSK_LEN) {
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wpa_hexdump_ascii(MSG_DEBUG, "EAP-PSK: invalid password in "
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"user database for ID_P",
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data->id_p, data->id_p_len);
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data->state = FAILURE;
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return;
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}
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eap_psk_key_setup(sm->user->password, data->ak, data->kdk);
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wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: AK", data->ak, EAP_PSK_AK_LEN);
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wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: KDK", data->kdk, EAP_PSK_KDK_LEN);
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wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: RAND_P (client rand)",
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resp->rand_p, EAP_PSK_RAND_LEN);
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memcpy(data->rand_p, resp->rand_p, EAP_PSK_RAND_LEN);
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/* MAC_P = OMAC1-AES-128(AK, ID_P||ID_S||RAND_S||RAND_P) */
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buflen = data->id_p_len + data->id_s_len + 2 * EAP_PSK_RAND_LEN;
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buf = malloc(buflen);
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if (buf == NULL) {
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data->state = FAILURE;
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return;
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}
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memcpy(buf, data->id_p, data->id_p_len);
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pos = buf + data->id_p_len;
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memcpy(pos, data->id_s, data->id_s_len);
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pos += data->id_s_len;
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memcpy(pos, data->rand_s, EAP_PSK_RAND_LEN);
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pos += EAP_PSK_RAND_LEN;
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memcpy(pos, data->rand_p, EAP_PSK_RAND_LEN);
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omac1_aes_128(data->ak, buf, buflen, mac);
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free(buf);
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wpa_hexdump(MSG_DEBUG, "EAP-PSK: MAC_P", resp->mac_p, EAP_PSK_MAC_LEN);
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if (memcmp(mac, resp->mac_p, EAP_PSK_MAC_LEN) != 0) {
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wpa_printf(MSG_INFO, "EAP-PSK: Invalid MAC_P");
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wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: Expected MAC_P",
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mac, EAP_PSK_MAC_LEN);
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data->state = FAILURE;
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return;
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}
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data->state = PSK_3;
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}
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static void eap_psk_process_4(struct eap_sm *sm,
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struct eap_psk_data *data,
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u8 *respData, size_t respDataLen)
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{
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struct eap_psk_hdr_4 *resp;
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u8 *pos, *decrypted, nonce[16], *tag;
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size_t left;
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if (data->state != PSK_3)
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return;
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wpa_printf(MSG_DEBUG, "EAP-PSK: Received PSK-4");
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resp = (struct eap_psk_hdr_4 *) respData;
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pos = (u8 *) (resp + 1);
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left = ntohs(resp->length) - sizeof(*resp);
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wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: Encrypted PCHANNEL", pos, left);
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if (left < 4 + 16 + 1) {
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wpa_printf(MSG_INFO, "EAP-PSK: Too short PCHANNEL data in "
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"PSK-4 (len=%lu, expected 21)",
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(unsigned long) left);
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return;
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}
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if (pos[0] == 0 && pos[1] == 0 && pos[2] == 0 && pos[3] == 0) {
|
||
|
|
wpa_printf(MSG_DEBUG, "EAP-PSK: Nonce did not increase");
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
memset(nonce, 0, 12);
|
||
|
|
memcpy(nonce + 12, pos, 4);
|
||
|
|
pos += 4;
|
||
|
|
left -= 4;
|
||
|
|
tag = pos;
|
||
|
|
pos += 16;
|
||
|
|
left -= 16;
|
||
|
|
|
||
|
|
decrypted = malloc(left);
|
||
|
|
if (decrypted == NULL)
|
||
|
|
return;
|
||
|
|
memcpy(decrypted, pos, left);
|
||
|
|
|
||
|
|
if (aes_128_eax_decrypt(data->tek, nonce, sizeof(nonce),
|
||
|
|
respData, 22, decrypted, left, tag)) {
|
||
|
|
wpa_printf(MSG_WARNING, "EAP-PSK: PCHANNEL decryption failed");
|
||
|
|
free(decrypted);
|
||
|
|
data->state = FAILURE;
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
wpa_hexdump(MSG_DEBUG, "EAP-PSK: Decrypted PCHANNEL message",
|
||
|
|
decrypted, left);
|
||
|
|
|
||
|
|
/* Verify R flag */
|
||
|
|
switch (decrypted[0] >> 6) {
|
||
|
|
case EAP_PSK_R_FLAG_CONT:
|
||
|
|
wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - CONT - unsupported");
|
||
|
|
data->state = FAILURE;
|
||
|
|
break;
|
||
|
|
case EAP_PSK_R_FLAG_DONE_SUCCESS:
|
||
|
|
wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - DONE_SUCCESS");
|
||
|
|
data->state = SUCCESS;
|
||
|
|
break;
|
||
|
|
case EAP_PSK_R_FLAG_DONE_FAILURE:
|
||
|
|
wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - DONE_FAILURE");
|
||
|
|
data->state = FAILURE;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
free(decrypted);
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
static void eap_psk_process(struct eap_sm *sm, void *priv,
|
||
|
|
u8 *respData, size_t respDataLen)
|
||
|
|
{
|
||
|
|
struct eap_psk_data *data = priv;
|
||
|
|
struct eap_psk_hdr *resp;
|
||
|
|
|
||
|
|
if (sm->user == NULL || sm->user->password == NULL) {
|
||
|
|
wpa_printf(MSG_INFO, "EAP-MSCHAPV2: Password not configured");
|
||
|
|
data->state = FAILURE;
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
resp = (struct eap_psk_hdr *) respData;
|
||
|
|
|
||
|
|
switch (resp->flags & 0x03) {
|
||
|
|
case 1:
|
||
|
|
eap_psk_process_2(sm, data, respData, respDataLen);
|
||
|
|
break;
|
||
|
|
case 3:
|
||
|
|
eap_psk_process_4(sm, data, respData, respDataLen);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
static Boolean eap_psk_isDone(struct eap_sm *sm, void *priv)
|
||
|
|
{
|
||
|
|
struct eap_psk_data *data = priv;
|
||
|
|
return data->state == SUCCESS || data->state == FAILURE;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
static u8 * eap_psk_getKey(struct eap_sm *sm, void *priv, size_t *len)
|
||
|
|
{
|
||
|
|
struct eap_psk_data *data = priv;
|
||
|
|
u8 *key;
|
||
|
|
|
||
|
|
if (data->state != SUCCESS)
|
||
|
|
return NULL;
|
||
|
|
|
||
|
|
key = malloc(EAP_PSK_MSK_LEN);
|
||
|
|
if (key == NULL)
|
||
|
|
return NULL;
|
||
|
|
memcpy(key, data->msk, EAP_PSK_MSK_LEN);
|
||
|
|
*len = EAP_PSK_MSK_LEN;
|
||
|
|
|
||
|
|
return key;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
static Boolean eap_psk_isSuccess(struct eap_sm *sm, void *priv)
|
||
|
|
{
|
||
|
|
struct eap_psk_data *data = priv;
|
||
|
|
return data->state == SUCCESS;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
const struct eap_method eap_method_psk =
|
||
|
|
{
|
||
|
|
.method = EAP_TYPE_PSK,
|
||
|
|
.name = "PSK",
|
||
|
|
.init = eap_psk_init,
|
||
|
|
.reset = eap_psk_reset,
|
||
|
|
.buildReq = eap_psk_buildReq,
|
||
|
|
.check = eap_psk_check,
|
||
|
|
.process = eap_psk_process,
|
||
|
|
.isDone = eap_psk_isDone,
|
||
|
|
.getKey = eap_psk_getKey,
|
||
|
|
.isSuccess = eap_psk_isSuccess,
|
||
|
|
};
|