freebsd-dev/contrib/hostapd/eap_psk.c
2006-03-07 05:47:04 +00:00

459 lines
11 KiB
C

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