ieee802_11.c

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/*
 * Host AP (software wireless LAN access point) user space daemon for
 * Host AP kernel driver / IEEE 802.11 Management
 * Copyright (c) 2002-2005, Jouni Malinen <[e-mail]>
 *
 * 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.
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <time.h>

#include "eloop.h"
#include "hostapd.h"
#include "ieee802_11.h"
#include "radius.h"
#include "radius_client.h"
#include "ieee802_11_auth.h"
#include "sta_info.h"
#include "eapol_sm.h"
#include "rc4.h"
#include "ieee802_1x.h"
#include "wpa.h"
#include "accounting.h"
#include "driver.h"


static u8 * hostapd_eid_supp_rates(hostapd *hapd, u8 *eid)
{
	u8 *pos = eid;

	*pos++ = WLAN_EID_SUPP_RATES;
	*pos++ = 4; /* len */
	*pos++ = 0x82; /* 1 Mbps, base set */
	*pos++ = 0x84; /* 2 Mbps, base set */
	*pos++ = 0x0b; /* 5.5 Mbps */
	*pos++ = 0x16; /* 11 Mbps */

	return pos;
}


static u16 hostapd_own_capab_info(hostapd *hapd)
{
	int capab = WLAN_CAPABILITY_ESS;
	if (hapd->conf->wpa ||
	    (hapd->conf->ieee802_1x &&
	     (hapd->conf->default_wep_key_len ||
	      hapd->conf->individual_wep_key_len)))
		capab |= WLAN_CAPABILITY_PRIVACY;
	return capab;
}


static const u8 WPA_OUI_TYPE[] = { 0x00, 0x50, 0xf2, 1 };

ParseRes ieee802_11_parse_elems(struct hostapd_data *hapd, u8 *start,
				size_t len,
				struct ieee802_11_elems *elems,
				int show_errors)
{
	size_t left = len;
	u8 *pos = start;
	int unknown = 0;

	memset(elems, 0, sizeof(*elems));

	while (left >= 2) {
		u8 id, elen;

		id = *pos++;
		elen = *pos++;
		left -= 2;

		if (elen > left) {
			if (show_errors) {
				HOSTAPD_DEBUG(HOSTAPD_DEBUG_MINIMAL,
					      "IEEE 802.11 element parse "
					      "failed (id=%d elen=%d "
					      "left=%lu)\n",
					      id, elen, (unsigned long) left);
				if (HOSTAPD_DEBUG_COND(HOSTAPD_DEBUG_MINIMAL))
					hostapd_hexdump("IEs", start, len);
			}
			return ParseFailed;
		}

		switch (id) {
		case WLAN_EID_SSID:
			elems->ssid = pos;
			elems->ssid_len = elen;
			break;
		case WLAN_EID_SUPP_RATES:
			elems->supp_rates = pos;
			elems->supp_rates_len = elen;
			break;
		case WLAN_EID_FH_PARAMS:
			elems->fh_params = pos;
			elems->fh_params_len = elen;
			break;
		case WLAN_EID_DS_PARAMS:
			elems->ds_params = pos;
			elems->ds_params_len = elen;
			break;
		case WLAN_EID_CF_PARAMS:
			elems->cf_params = pos;
			elems->cf_params_len = elen;
			break;
		case WLAN_EID_TIM:
			elems->tim = pos;
			elems->tim_len = elen;
			break;
		case WLAN_EID_IBSS_PARAMS:
			elems->ibss_params = pos;
			elems->ibss_params_len = elen;
			break;
		case WLAN_EID_CHALLENGE:
			elems->challenge = pos;
			elems->challenge_len = elen;
			break;
		case WLAN_EID_GENERIC:
			if (elen > 4 && memcmp(pos, WPA_OUI_TYPE, 4) == 0) {
				elems->wpa_ie = pos;
				elems->wpa_ie_len = elen;
			} else if (show_errors) {
				HOSTAPD_DEBUG(HOSTAPD_DEBUG_EXCESSIVE,
					      "IEEE 802.11 element parse "
					      "ignored unknown generic element"
					      " (id=%d elen=%d OUI:type="
					      "%02x-%02x-%02x:%d)\n",
					      id, elen,
					      elen >= 1 ? pos[0] : 0,
					      elen >= 2 ? pos[1] : 0,
					      elen >= 3 ? pos[2] : 0,
					      elen >= 4 ? pos[3] : 0);
				unknown++;
			} else {
				unknown++;
			}
			break;
		case WLAN_EID_RSN:
			elems->rsn_ie = pos;
			elems->rsn_ie_len = elen;
			break;
		default:
			unknown++;
			if (!show_errors)
				break;
			HOSTAPD_DEBUG(HOSTAPD_DEBUG_EXCESSIVE,
				      "IEEE 802.11 element parse ignored "
				      "unknown element (id=%d elen=%d)\n",
				      id, elen);
			break;
		}

		left -= elen;
		pos += elen;
	}

	if (left)
		return ParseFailed;

	return unknown ? ParseUnknown : ParseOK;
}


static void ieee802_11_print_ssid(const u8 *ssid, u8 len)
{
	int i;
	for (i = 0; i < len; i++) {
		if (ssid[i] >= 32 && ssid[i] < 127)
			printf("%c", ssid[i]);
		else
			printf("<%02x>", ssid[i]);
	}
}


static void ieee802_11_sta_authenticate(void *eloop_ctx, void *timeout_ctx)
{
	hostapd *hapd = eloop_ctx;
	struct ieee80211_mgmt mgmt;

	if (hapd->assoc_ap_state == WAIT_BEACON)
		hapd->assoc_ap_state = AUTHENTICATE;
	if (hapd->assoc_ap_state != AUTHENTICATE)
		return;

	printf("Authenticate with AP " MACSTR " SSID=",
	       MAC2STR(hapd->conf->assoc_ap_addr));
	ieee802_11_print_ssid((u8 *) hapd->assoc_ap_ssid,
			      hapd->assoc_ap_ssid_len);
	printf(" (as station)\n");

	memset(&mgmt, 0, sizeof(mgmt));
	mgmt.frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
					  WLAN_FC_STYPE_AUTH);
	/* Request TX callback */
	mgmt.frame_control |= host_to_le16(BIT(1));
	memcpy(mgmt.da, hapd->conf->assoc_ap_addr, ETH_ALEN);
	memcpy(mgmt.sa, hapd->own_addr, ETH_ALEN);
	memcpy(mgmt.bssid, hapd->conf->assoc_ap_addr, ETH_ALEN);
	mgmt.u.auth.auth_alg = host_to_le16(WLAN_AUTH_OPEN);
	mgmt.u.auth.auth_transaction = host_to_le16(1);
	mgmt.u.auth.status_code = host_to_le16(0);
	if (hostapd_send_mgmt_frame(hapd, &mgmt, IEEE80211_HDRLEN +
				    sizeof(mgmt.u.auth), 0) < 0)
		perror("ieee802_11_sta_authenticate: send");

	/* Try to authenticate again, if this attempt fails or times out. */
	eloop_register_timeout(5, 0, ieee802_11_sta_authenticate, hapd, NULL);
}


static void ieee802_11_sta_associate(void *eloop_ctx, void *timeout_ctx)
{
	hostapd *hapd = eloop_ctx;
	u8 buf[256];
	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) buf;
	u8 *p;

	if (hapd->assoc_ap_state == AUTHENTICATE)
		hapd->assoc_ap_state = ASSOCIATE;
	if (hapd->assoc_ap_state != ASSOCIATE)
		return;

	printf("Associate with AP " MACSTR " SSID=",
	       MAC2STR(hapd->conf->assoc_ap_addr));
	ieee802_11_print_ssid((u8 *) hapd->assoc_ap_ssid,
			      hapd->assoc_ap_ssid_len);
	printf(" (as station)\n");

	memset(mgmt, 0, sizeof(*mgmt));
	mgmt->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
					  WLAN_FC_STYPE_ASSOC_REQ);
	/* Request TX callback */
	mgmt->frame_control |= host_to_le16(BIT(1));
	memcpy(mgmt->da, hapd->conf->assoc_ap_addr, ETH_ALEN);
	memcpy(mgmt->sa, hapd->own_addr, ETH_ALEN);
	memcpy(mgmt->bssid, hapd->conf->assoc_ap_addr, ETH_ALEN);
	mgmt->u.assoc_req.capab_info = host_to_le16(0);
	mgmt->u.assoc_req.listen_interval = host_to_le16(1);
	p = &mgmt->u.assoc_req.variable[0];

	*p++ = WLAN_EID_SSID;
	*p++ = hapd->assoc_ap_ssid_len;
	memcpy(p, hapd->assoc_ap_ssid, hapd->assoc_ap_ssid_len);
	p += hapd->assoc_ap_ssid_len;

	p = hostapd_eid_supp_rates(hapd, p);

	if (hostapd_send_mgmt_frame(hapd, mgmt, p - (u8 *) mgmt, 0) < 0)
		perror("ieee802_11_sta_associate: send");

	/* Try to authenticate again, if this attempt fails or times out. */
	eloop_register_timeout(5, 0, ieee802_11_sta_associate, hapd, NULL);
}


static u16 auth_shared_key(hostapd *hapd, struct sta_info *sta,
			   u16 auth_transaction, u8 *challenge, int iswep)
{
	hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211,
		       HOSTAPD_LEVEL_DEBUG,
		       "authentication (shared key, transaction %d)",
		       auth_transaction);

	if (auth_transaction == 1) {
		if (!sta->challenge) {
			/* Generate a pseudo-random challenge */
			u8 key[8];
			time_t now;
			int r;
			sta->challenge = malloc(WLAN_AUTH_CHALLENGE_LEN);
			if (!sta->challenge)
				return WLAN_STATUS_UNSPECIFIED_FAILURE;
			memset(sta->challenge, 0, WLAN_AUTH_CHALLENGE_LEN);

			now = time(NULL);
			r = random();
			memcpy(key, &now, 4);
			memcpy(key + 4, &r, 4);
			rc4(sta->challenge, WLAN_AUTH_CHALLENGE_LEN,
			    key, sizeof(key));
		}
		return 0;
	}

	if (auth_transaction != 3)
		return WLAN_STATUS_UNSPECIFIED_FAILURE;

	/* Transaction 3 */
	if (!iswep || !sta->challenge || !challenge ||
	    memcmp(sta->challenge, challenge, WLAN_AUTH_CHALLENGE_LEN)) {
		hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211,
			       HOSTAPD_LEVEL_INFO,
			       "shared key authentication - invalid "
			       "challenge-response");
		return WLAN_STATUS_CHALLENGE_FAIL;
	}

	hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_IEEE80211,
		       HOSTAPD_LEVEL_DEBUG,
		       "authentication OK (shared key)");
#ifdef IEEE80211_REQUIRE_AUTH_ACK
	/* Station will be marked authenticated if it ACKs the
	 * authentication reply. */
#else
	sta->flags |= WLAN_STA_AUTH;
	wpa_sm_event(hapd, sta, WPA_AUTH);
#endif
	free(sta->challenge);
	sta->challenge = NULL;

	return 0;
}


static void send_auth_reply(hostapd *hapd, struct ieee80211_mgmt *mgmt,
			    u16 auth_alg, u16 auth_transaction, u16 resp,
			    u8 *challenge)
{
	u8 buf[IEEE80211_HDRLEN + sizeof(mgmt->u.auth) + 2 +
	       WLAN_AUTH_CHALLENGE_LEN];
	struct ieee80211_mgmt *reply;
	size_t rlen;

	memset(buf, 0, sizeof(buf));
	reply = (struct ieee80211_mgmt *) buf;
	reply->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
					   WLAN_FC_STYPE_AUTH);
	/* Request TX callback */
	reply->frame_control |= host_to_le16(BIT(1));
	memcpy(reply->da, mgmt->sa, ETH_ALEN);
	memcpy(reply->sa, hapd->own_addr, ETH_ALEN);
	memcpy(reply->bssid, mgmt->bssid, ETH_ALEN);

	reply->u.auth.auth_alg = host_to_le16(auth_alg);
	reply->u.auth.auth_transaction = host_to_le16(auth_transaction);
	reply->u.auth.status_code = host_to_le16(resp);
	rlen = IEEE80211_HDRLEN + sizeof(reply->u.auth);
	if (auth_alg == WLAN_AUTH_SHARED_KEY && auth_transaction == 2 &&
	    challenge) {
		u8 *p = reply->u.auth.variable;
		*p++ = WLAN_EID_CHALLENGE;
		*p++ = WLAN_AUTH_CHALLENGE_LEN;
		memcpy(p, challenge, WLAN_AUTH_CHALLENGE_LEN);
		rlen += 2 + WLAN_AUTH_CHALLENGE_LEN;
	} else
		challenge = NULL;

	HOSTAPD_DEBUG(HOSTAPD_DEBUG_MINIMAL,
		      "authentication reply: STA=" MACSTR " auth_alg=%d "
		      "auth_transaction=%d resp=%d%s\n",
		      MAC2STR(mgmt->sa), auth_alg, auth_transaction,
		      resp, challenge ? " challenge" : "");
	if (hostapd_send_mgmt_frame(hapd, reply, rlen, 0) < 0)
		perror("send_auth_reply: send");
}


static void handle_auth(hostapd *hapd, struct ieee80211_mgmt *mgmt, size_t len)
{
	u16 auth_alg, auth_transaction, status_code;
	u16 resp = WLAN_STATUS_SUCCESS;
	struct sta_info *sta = NULL;
	int res;
	u16 fc;
	u8 *challenge = NULL;
	u32 session_timeout, acct_interim_interval;

	if (len < IEEE80211_HDRLEN + sizeof(mgmt->u.auth)) {
		printf("handle_auth - too short payload (len=%lu)\n",
		       (unsigned long) len);
		return;
	}

	auth_alg = le_to_host16(mgmt->u.auth.auth_alg);
	auth_transaction = le_to_host16(mgmt->u.auth.auth_transaction);
	status_code = le_to_host16(mgmt->u.auth.status_code);
	fc = le_to_host16(mgmt->frame_control);

	if (len >= IEEE80211_HDRLEN + sizeof(mgmt->u.auth) +
	    2 + WLAN_AUTH_CHALLENGE_LEN &&
	    mgmt->u.auth.variable[0] == WLAN_EID_CHALLENGE &&
	    mgmt->u.auth.variable[1] == WLAN_AUTH_CHALLENGE_LEN)
		challenge = &mgmt->u.auth.variable[2];

	HOSTAPD_DEBUG(HOSTAPD_DEBUG_MINIMAL,
		      "authentication: STA=" MACSTR " auth_alg=%d "
		      "auth_transaction=%d status_code=%d wep=%d%s\n",
		      MAC2STR(mgmt->sa), auth_alg, auth_transaction,
		      status_code, !!(fc & WLAN_FC_ISWEP),
		      challenge ? " challenge" : "");

	if (hapd->assoc_ap_state == AUTHENTICATE && auth_transaction == 2 &&