radius_server.c

hostapd源代码

/*
 * hostapd / RADIUS authentication server
 * Copyright (c) 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 "includes.h"
#include <net/if.h>

#include "common.h"
#include "radius.h"
#include "eloop.h"
#include "config.h"
#include "eap.h"
#include "radius_server.h"

#define RADIUS_SESSION_TIMEOUT 60
#define RADIUS_MAX_SESSION 100
#define RADIUS_MAX_MSG_LEN 3000

static struct eapol_callbacks radius_server_eapol_cb;

struct radius_client;
struct radius_server_data;

struct radius_session {
	struct radius_session *next;
	struct radius_client *client;
	struct radius_server_data *server;
	unsigned int sess_id;
	struct eap_sm *eap;
	u8 *eapKeyData, *eapReqData;
	size_t eapKeyDataLen, eapReqDataLen;
	Boolean eapSuccess, eapRestart, eapFail, eapResp, eapReq, eapNoReq;
	Boolean portEnabled, eapTimeout;

	struct radius_msg *last_msg;
	char *last_from_addr;
	int last_from_port;
	struct sockaddr_storage last_from;
	socklen_t last_fromlen;
};

struct radius_client {
	struct radius_client *next;
	struct in_addr addr;
	struct in_addr mask;
#ifdef CONFIG_IPV6
	struct in6_addr addr6;
	struct in6_addr mask6;
#endif /* CONFIG_IPV6 */
	char *shared_secret;
	int shared_secret_len;
	struct radius_session *sessions;
};

struct radius_server_data {
	int auth_sock;
	struct radius_client *clients;
	unsigned int next_sess_id;
	void *hostapd_conf;
	int num_sess;
	void *eap_sim_db_priv;
	void *ssl_ctx;
	int ipv6;
};


extern int wpa_debug_level;

#define RADIUS_DEBUG(args...) \
wpa_printf(MSG_DEBUG, "RADIUS SRV: " args)
#define RADIUS_ERROR(args...) \
wpa_printf(MSG_ERROR, "RADIUS SRV: " args)
#define RADIUS_DUMP(args...) \
wpa_hexdump(MSG_MSGDUMP, "RADIUS SRV: " args)
#define RADIUS_DUMP_ASCII(args...) \
wpa_hexdump_ascii(MSG_MSGDUMP, "RADIUS SRV: " args)


static void radius_server_session_timeout(void *eloop_ctx, void *timeout_ctx);



static struct radius_client *
radius_server_get_client(struct radius_server_data *data, struct in_addr *addr,
			 int ipv6)
{
	struct radius_client *client = data->clients;

	while (client) {
#ifdef CONFIG_IPV6
		if (ipv6) {
			struct in6_addr *addr6;
			int i;

			addr6 = (struct in6_addr *) addr;
			for (i = 0; i < 16; i++) {
				if ((addr6->s6_addr[i] &
				     client->mask6.s6_addr[i]) !=
				    (client->addr6.s6_addr[i] &
				     client->mask6.s6_addr[i])) {
					i = 17;
					break;
				}
			}
			if (i == 16) {
				break;
			}
		}
#endif /* CONFIG_IPV6 */
		if (!ipv6 && (client->addr.s_addr & client->mask.s_addr) ==
		    (addr->s_addr & client->mask.s_addr)) {
			break;
		}

		client = client->next;
	}

	return client;
}


static struct radius_session *
radius_server_get_session(struct radius_client *client, unsigned int sess_id)
{
	struct radius_session *sess = client->sessions;

	while (sess) {
		if (sess->sess_id == sess_id) {
			break;
		}
		sess = sess->next;
	}

	return sess;
}


static void radius_server_session_free(struct radius_server_data *data,
				       struct radius_session *sess)
{
	eloop_cancel_timeout(radius_server_session_timeout, data, sess);
	free(sess->eapKeyData);
	free(sess->eapReqData);
	eap_sm_deinit(sess->eap);
	if (sess->last_msg) {
		radius_msg_free(sess->last_msg);
		free(sess->last_msg);
	}
	free(sess->last_from_addr);
	free(sess);
	data->num_sess--;
}


static void radius_server_session_remove(struct radius_server_data *data,
					 struct radius_session *sess)
{
	struct radius_client *client = sess->client;
	struct radius_session *session, *prev;

	prev = NULL;
	session = client->sessions;
	while (session) {
		if (session == sess) {
			if (prev == NULL) {
				client->sessions = sess->next;
			} else {
				prev->next = sess->next;
			}
			radius_server_session_free(data, sess);
			break;
		}
		prev = session;
		session = session->next;
	}
}


static void radius_server_session_timeout(void *eloop_ctx, void *timeout_ctx)
{
	struct radius_server_data *data = eloop_ctx;
	struct radius_session *sess = timeout_ctx;

	RADIUS_DEBUG("Timing out authentication session 0x%x", sess->sess_id);
	radius_server_session_remove(data, sess);
}


static struct radius_session *
radius_server_new_session(struct radius_server_data *data,
			  struct radius_client *client)
{
	struct radius_session *sess;

	if (data->num_sess >= RADIUS_MAX_SESSION) {
		RADIUS_DEBUG("Maximum number of existing session - no room "
			     "for a new session");
		return NULL;
	}

	sess = wpa_zalloc(sizeof(*sess));
	if (sess == NULL)
		return NULL;

	sess->server = data;
	sess->client = client;
	sess->sess_id = data->next_sess_id++;
	sess->next = client->sessions;
	client->sessions = sess;
	eloop_register_timeout(RADIUS_SESSION_TIMEOUT, 0,
			       radius_server_session_timeout, data, sess);
	data->num_sess++;
	return sess;
}


static struct radius_session *
radius_server_get_new_session(struct radius_server_data *data,
			      struct radius_client *client,
			      struct radius_msg *msg)
{
	u8 *user;
	size_t user_len;
	const struct hostapd_eap_user *eap_user;
	int res;
	struct radius_session *sess;
	struct eap_config eap_conf;

	RADIUS_DEBUG("Creating a new session");

	user = malloc(256);
	if (user == NULL) {
		return NULL;
	}
	res = radius_msg_get_attr(msg, RADIUS_ATTR_USER_NAME, user, 256);
	if (res < 0 || res > 256) {
		RADIUS_DEBUG("Could not get User-Name");
		free(user);
		return NULL;
	}
	user_len = res;
	RADIUS_DUMP_ASCII("User-Name", user, user_len);

	eap_user = hostapd_get_eap_user(data->hostapd_conf, user, user_len, 0);
	free(user);

	if (eap_user) {
		RADIUS_DEBUG("Matching user entry found");
		sess = radius_server_new_session(data, client);
		if (sess == NULL) {
			RADIUS_DEBUG("Failed to create a new session");
			return NULL;
		}
	} else {
		RADIUS_DEBUG("User-Name not found from user database");
		return NULL;
	}

	memset(&eap_conf, 0, sizeof(eap_conf));
	eap_conf.ssl_ctx = data->ssl_ctx;
	eap_conf.eap_sim_db_priv = data->eap_sim_db_priv;
	eap_conf.backend_auth = TRUE;
	sess->eap = eap_sm_init(sess, &radius_server_eapol_cb, &eap_conf);
	if (sess->eap == NULL) {
		RADIUS_DEBUG("Failed to initialize EAP state machine for the "
			     "new session");
		radius_server_session_free(data, sess);
		return NULL;
	}
	sess->eapRestart = TRUE;
	sess->portEnabled = TRUE;

	RADIUS_DEBUG("New session 0x%x initialized", sess->sess_id);

	return sess;
}


static struct radius_msg *
radius_server_encapsulate_eap(struct radius_server_data *data,
			      struct radius_client *client,
			      struct radius_session *sess,
			      struct radius_msg *request)
{
	struct radius_msg *msg;
	int code;
	unsigned int sess_id;

	if (sess->eapFail) {
		code = RADIUS_CODE_ACCESS_REJECT;
	} else if (sess->eapSuccess) {
		code = RADIUS_CODE_ACCESS_ACCEPT;
	} else {
		code = RADIUS_CODE_ACCESS_CHALLENGE;
	}

	msg = radius_msg_new(code, request->hdr->identifier);
	if (msg == NULL) {
		return NULL;
	}

	sess_id = htonl(sess->sess_id);
	if (code == RADIUS_CODE_ACCESS_CHALLENGE &&
	    !radius_msg_add_attr(msg, RADIUS_ATTR_STATE,
				 (u8 *) &sess_id, sizeof(sess_id))) {
		RADIUS_DEBUG("Failed to add State attribute");
	}

	if (sess->eapReqData &&
	    !radius_msg_add_eap(msg, sess->eapReqData, sess->eapReqDataLen)) {
		RADIUS_DEBUG("Failed to add EAP-Message attribute");
	}

	if (code == RADIUS_CODE_ACCESS_ACCEPT && sess->eapKeyData) {
		int len;
		if (sess->eapKeyDataLen > 64) {
			len = 32;
		} else {
			len = sess->eapKeyDataLen / 2;
		}
		if (!radius_msg_add_mppe_keys(msg, request->hdr->authenticator,
					      (u8 *) client->shared_secret,
					      client->shared_secret_len,
					      sess->eapKeyData + len, len,
					      sess->eapKeyData, len)) {
			RADIUS_DEBUG("Failed to add MPPE key attributes");
		}
	}

	if (radius_msg_finish_srv(msg, (u8 *) client->shared_secret,
				  client->shared_secret_len,
				  request->hdr->authenticator) < 0) {
		RADIUS_DEBUG("Failed to add Message-Authenticator attribute");
	}

	return msg;
}


static int radius_server_reject(struct radius_server_data *data,
				struct radius_client *client,
				struct radius_msg *request,
				struct sockaddr *from, socklen_t fromlen,
				const char *from_addr, int from_port)
{
	struct radius_msg *msg;
	int ret = 0;
	struct eap_hdr eapfail;

	RADIUS_DEBUG("Reject invalid request from %s:%d",
		     from_addr, from_port);

	msg = radius_msg_new(RADIUS_CODE_ACCESS_REJECT,
			     request->hdr->identifier);
	if (msg == NULL) {
		return -1;
	}

	memset(&eapfail, 0, sizeof(eapfail));
	eapfail.code = EAP_CODE_FAILURE;
	eapfail.identifier = 0;
	eapfail.length = htons(sizeof(eapfail));

	if (!radius_msg_add_eap(msg, (u8 *) &eapfail, sizeof(eapfail))) {
		RADIUS_DEBUG("Failed to add EAP-Message attribute");
	}


	if (radius_msg_finish_srv(msg, (u8 *) client->shared_secret,
				  client->shared_secret_len,
				  request->hdr->authenticator) < 0) {
		RADIUS_DEBUG("Failed to add Message-Authenticator attribute");
	}

	if (wpa_debug_level <= MSG_MSGDUMP) {
		radius_msg_dump(msg);
	}

	if (sendto(data->auth_sock, msg->buf, msg->buf_used, 0,
		   (struct sockaddr *) from, sizeof(*from)) < 0) {
		perror("sendto[RADIUS SRV]");
		ret = -1;
	}

	radius_msg_free(msg);
	free(msg);

	return ret;
}


static int radius_server_request(struct radius_server_data *data,
				 struct radius_msg *msg,
				 struct sockaddr *from, socklen_t fromlen,
				 struct radius_client *client,
				 const char *from_addr, int from_port,
				 struct radius_session *force_sess)
{
	u8 *eap = NULL;
	size_t eap_len;
	int res, state_included = 0;
	u8 statebuf[4], resp_id;
	unsigned int state;
	struct radius_session *sess;
	struct radius_msg *reply;
	struct eap_hdr *hdr;

	/* TODO: Implement duplicate packet processing */

	if (force_sess)
		sess = force_sess;
	else {
		res = radius_msg_get_attr(msg, RADIUS_ATTR_STATE, statebuf,
					  sizeof(statebuf));
		state_included = res >= 0;
		if (res == sizeof(statebuf)) {
			state = (statebuf[0] << 24) | (statebuf[1] << 16) |
				(statebuf[2] << 8) | statebuf[3];
			sess = radius_server_get_session(client, state);
		} else {
			sess = NULL;
		}
	}

	if (sess) {
		RADIUS_DEBUG("Request for session 0x%x", sess->sess_id);
	} else if (state_included) {
		RADIUS_DEBUG("State attribute included but no session found");
		radius_server_reject(data, client, msg, from, fromlen,
				     from_addr, from_port);
		return -1;
	} else {
		sess = radius_server_get_new_session(data, client, msg);
		if (sess == NULL) {
			RADIUS_DEBUG("Could not create a new session");
			radius_server_reject(data, client, msg, from, fromlen,
					     from_addr, from_port);
			return -1;
		}
	}

	eap = radius_msg_get_eap(msg, &eap_len);
	if (eap == NULL) {
		RADIUS_DEBUG("No EAP-Message in RADIUS packet from %s",
			     from_addr);
		return -1;
	}

	RADIUS_DUMP("Received EAP data", eap, eap_len);
	if (eap_len >= sizeof(*hdr)) {
		hdr = (struct eap_hdr *) eap;
		resp_id = hdr->identifier;
	} else {
		resp_id = 0;
	}

	/* FIX: if Code is Request, Success, or Failure, send Access-Reject;
	 * RFC3579 Sect. 2.6.2.
	 * Include EAP-Response/Nak with no preferred method if
	 * code == request.
	 * If code is not 1-4, discard the packet silently.
	 * Or is this already done by the EAP state machine? */

	eap_set_eapRespData(sess->eap, eap, eap_len);
	free(eap);
	eap = NULL;
	sess->eapResp = TRUE;
	eap_sm_step(sess->eap);

	if (sess->eapReqData) {
		RADIUS_DUMP("EAP data from the state machine",
			    sess->eapReqData, sess->eapReqDataLen);
	} else if (sess->eapFail) {
		RADIUS_DEBUG("No EAP data from the state machine, but eapFail "
			     "set - generate EAP-Failure");
		hdr = wpa_zalloc(sizeof(*hdr));
		if (hdr) {
			hdr->identifier = resp_id;
			hdr->length = htons(sizeof(*hdr));
			sess->eapReqData = (u8 *) hdr;
			sess->eapReqDataLen = sizeof(*hdr);
		}
	} else if (eap_sm_method_pending(sess->eap)) {
		if (sess->last_msg) {
			radius_msg_free(sess->last_msg);
			free(sess->last_msg);
		}
		sess->last_msg = msg;
		sess->last_from_port = from_port;
		free(sess->last_from_addr);
		sess->last_from_addr = strdup(from_addr);
		sess->last_fromlen = fromlen;
		memcpy(&sess->last_from, from, fromlen);
		return -2;
	} else {
		RADIUS_DEBUG("No EAP data from the state machine - ignore this"
			     " Access-Request silently (assuming it was a "
			     "duplicate)");
		return -1;
	}

	reply = radius_server_encapsulate_eap(data, client, sess, msg);

	free(sess->eapReqData);
	sess->eapReqData = NULL;
	sess->eapReqDataLen = 0;

	if (reply) {
		RADIUS_DEBUG("Reply to %s:%d", from_addr, from_port);
		if (wpa_debug_level <= MSG_MSGDUMP) {
			radius_msg_dump(reply);
		}

		res = sendto(data->auth_sock, reply->buf, reply->buf_used, 0,
			     (struct sockaddr *) from, fromlen);
		if (res < 0) {
			perror("sendto[RADIUS SRV]");
		}
		radius_msg_free(reply);
		free(reply);
	}

	if (sess->eapSuccess || sess->eapFail) {
		RADIUS_DEBUG("Removing completed session 0x%x", sess->sess_id);
		radius_server_session_remove(data, sess);
	}

	return 0;
}


static void radius_server_receive_auth(int sock, void *eloop_ctx,
				       void *sock_ctx)
{
	struct radius_server_data *data = eloop_ctx;
	u8 *buf = NULL;
	struct sockaddr_storage from;
	socklen_t fromlen;
	int len;
	struct radius_client *client = NULL;
	struct radius_msg *msg = NULL;
	char abuf[50];
	int from_port = 0;

	buf = malloc(RADIUS_MAX_MSG_LEN);
	if (buf == NULL) {
		goto fail;
	}

	fromlen = sizeof(from);
	len = recvfrom(sock, buf, RADIUS_MAX_MSG_LEN, 0,
		       (struct sockaddr *) &from, &fromlen);
	if (len < 0) {
		perror("recvfrom[radius_server]");
		goto fail;
	}

#ifdef CONFIG_IPV6
	if (data->ipv6) {
		struct sockaddr_in6 *from6 = (struct sockaddr_in6 *) &from;
		if (inet_ntop(AF_INET6, &from6->sin6_addr, abuf, sizeof(abuf))