l2tp: define tunnel specific secrets

Store tunnel secret in the l2tp_conn_t structure so that different
tunnels may use different secrets.

The new "secret" option, added to the "l2tp create tunnel" command,
let the user define the secret to be used by the new tunnel.
By default, new tunnels keep using the "secret" option defined in
accel-ppp.conf.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>

1 files changed, 60 insertions, 21 deletions

diff --git a/accel-pppd/ctrl/l2tp/l2tp.c b/accel-pppd/ctrl/l2tp/l2tp.c
index 6b81022..531fab2 100644
--- a/accel-pppd/ctrl/l2tp/l2tp.c
+++ b/accel-pppd/ctrl/l2tp/l2tp.c
@@ -116,6 +116,8 @@ struct l2tp_conn_t
 	uint16_t port_set:1;
 	uint16_t challenge_len;
 	uint8_t *challenge;
+	size_t secret_len;
+	char *secret;
 
 	int retransmit;
 	uint16_t Ns, Nr;
@@ -238,7 +240,7 @@ static int l2tp_tunnel_genchall(uint16_t chall_len,
 	int err;
 
 	if (chall_len == 0
-	    || conf_secret == NULL || conf_secret_len == 0) {
+	    || conn->secret == NULL || conn->secret_len == 0) {
 		if (conn->challenge) {
 			_free(conn->challenge);
 			conn->challenge = NULL;
@@ -306,7 +308,7 @@ static int l2tp_tunnel_storechall(struct l2tp_conn_t *conn,
 		return 0;
 	}
 
-	if (conf_secret == NULL || conf_secret_len == 0) {
+	if (conn->secret == NULL || conn->secret_len == 0) {
 		log_tunnel(log_error, conn, "authentication required by peer,"
 			   " but no secret has been set for this tunnel\n");
 		goto err;
@@ -344,21 +346,21 @@ static int l2tp_tunnel_genchallresp(uint8_t msgident,
 	uint8_t challresp[MD5_DIGEST_LENGTH];
 
 	if (conn->challenge == NULL) {
-		if (conf_secret && conf_secret_len > 0) {
+		if (conn->secret && conn->secret_len > 0) {
 			log_tunnel(log_warn, conn,
 				   "no Challenge sent by peer\n");
 		}
 		return 0;
 	}
 
-	if (conf_secret == NULL || conf_secret_len == 0) {
+	if (conn->secret == NULL || conn->secret_len == 0) {
 		log_tunnel(log_error, conn,
 			   "impossible to generate Challenge Response:"
 			   " no secret set for this tunnel\n");
 		return -1;
 	}
 
-	comp_chap_md5(challresp, msgident, conf_secret, conf_secret_len,
+	comp_chap_md5(challresp, msgident, conn->secret, conn->secret_len,
 		      conn->challenge, conn->challenge_len);
 	if (l2tp_packet_add_octets(pack, Challenge_Response, challresp,
 				   MD5_DIGEST_LENGTH, 1) < 0) {
@@ -377,7 +379,7 @@ static int l2tp_tunnel_checkchallresp(uint8_t msgident,
 {
 	uint8_t challref[MD5_DIGEST_LENGTH];
 
-	if (conf_secret == NULL || conf_secret_len == 0) {
+	if (conn->secret == NULL || conn->secret_len == 0) {
 		if (challresp) {
 			log_tunnel(log_warn, conn,
 				   "discarding unexpected Challenge Response"
@@ -404,7 +406,7 @@ static int l2tp_tunnel_checkchallresp(uint8_t msgident,
 		return -1;
 	}
 
-	comp_chap_md5(challref, msgident, conf_secret, conf_secret_len,
+	comp_chap_md5(challref, msgident, conn->secret, conn->secret_len,
 		      conn->challenge, conn->challenge_len);
 	if (memcmp(challref, challresp->val.octets, MD5_DIGEST_LENGTH) != 0) {
 		log_tunnel(log_error, conn, "impossible to authenticate peer:"
@@ -427,7 +429,7 @@ static int l2tp_send_StopCCN(struct l2tp_conn_t *conn,
 
 	pack = l2tp_packet_alloc(2, Message_Type_Stop_Ctrl_Conn_Notify,
 				 &conn->peer_addr, conn->hide_avps,
-				 conf_secret, conf_secret_len);
+				 conn->secret, conn->secret_len);
 	if (pack == NULL) {
 		log_tunnel(log_error, conn, "impossible to send StopCCN:"
 			   " packet allocation failed\n");
@@ -470,7 +472,8 @@ static int l2tp_send_CDN(struct l2tp_sess_t *sess, uint16_t res, uint16_t err)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Call_Disconnect_Notify,
 				 &sess->paren_conn->peer_addr, sess->hide_avps,
-				 conf_secret, conf_secret_len);
+				 sess->paren_conn->secret,
+				 sess->paren_conn->secret_len);
 	if (pack == NULL) {
 		log_session(log_error, sess, "impossible to send CDN:"
 			    " packet allocation failed\n");
@@ -515,7 +518,7 @@ static int l2tp_tunnel_send_CDN(uint16_t sid, uint16_t peer_sid,
 
 	pack = l2tp_packet_alloc(2, Message_Type_Call_Disconnect_Notify,
 				 &conn->peer_addr, conn->hide_avps,
-				 conf_secret, conf_secret_len);
+				 conn->secret, conn->secret_len);
 	if (pack == NULL) {
 		log_tunnel(log_error, conn, "impossible to send CDN:"
 			   " packet allocation failed\n");
@@ -725,6 +728,9 @@ static void l2tp_tunnel_free(struct l2tp_conn_t *conn)
 	if (conn->challenge)
 		_free(conn->challenge);
 
+	if (conn->secret)
+		_free(conn->secret);
+
 	log_tunnel(log_info2, conn, "destroyed\n");
 
 	mempool_free(conn);
@@ -1515,7 +1521,8 @@ static void l2tp_send_HELLO(struct triton_timer_t *t)
 	log_tunnel(log_debug, conn, "sending HELLO\n");
 
 	pack = l2tp_packet_alloc(2, Message_Type_Hello, &conn->peer_addr,
-				 conn->hide_avps, conf_secret, conf_secret_len);
+				 conn->hide_avps, conn->secret,
+				 conn->secret_len);
 	if (!pack) {
 		log_tunnel(log_error, conn, "impossible to send HELLO:"
 			   " packet allocation failed\n");
@@ -1538,7 +1545,7 @@ static void l2tp_send_SCCRQ(void *peer_addr)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Start_Ctrl_Conn_Request,
 				 &conn->peer_addr, conn->hide_avps,
-				 conf_secret, conf_secret_len);
+				 conn->secret, conn->secret_len);
 	if (pack == NULL) {
 		log_tunnel(log_error, conn, "impossible to send SCCRQ:"
 			   " packet allocation failed\n");
@@ -1618,7 +1625,7 @@ static void l2tp_send_SCCRP(struct l2tp_conn_t *conn)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Start_Ctrl_Conn_Reply,
 				 &conn->peer_addr, conn->hide_avps,
-				 conf_secret, conf_secret_len);
+				 conn->secret, conn->secret_len);
 	if (!pack) {
 		log_tunnel(log_error, conn, "impossible to send SCCRP:"
 			   " packet allocation failed\n");
@@ -1703,7 +1710,7 @@ static int l2tp_send_SCCCN(struct l2tp_conn_t *conn)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Start_Ctrl_Conn_Connected,
 				 &conn->peer_addr, conn->hide_avps,
-				 conf_secret, conf_secret_len);
+				 conn->secret, conn->secret_len);
 	if (pack == NULL) {
 		log_tunnel(log_error, conn, "impossible to send SCCCN:"
 			   " packet allocation failed\n");
@@ -1740,7 +1747,8 @@ static int l2tp_send_ICRQ(struct l2tp_sess_t *sess)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Incoming_Call_Request,
 				 &sess->paren_conn->peer_addr, sess->hide_avps,
-				 conf_secret, conf_secret_len);
+				 sess->paren_conn->secret,
+				 sess->paren_conn->secret_len);
 	if (pack == NULL) {
 		log_session(log_error, sess, "impossible to send ICRQ:"
 			    " packet allocation failed\n");
@@ -1780,7 +1788,8 @@ static int l2tp_send_ICRP(struct l2tp_sess_t *sess)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Incoming_Call_Reply,
 				 &sess->paren_conn->peer_addr, sess->hide_avps,
-				 conf_secret, conf_secret_len);
+				 sess->paren_conn->secret,
+				 sess->paren_conn->secret_len);
 	if (!pack) {
 		log_session(log_error, sess, "impossible to send ICRP:"
 			    " packet allocation failed\n");
@@ -1815,7 +1824,8 @@ static int l2tp_send_ICCN(struct l2tp_sess_t *sess)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Incoming_Call_Connected,
 				 &sess->paren_conn->peer_addr, sess->hide_avps,
-				 conf_secret, conf_secret_len);
+				 sess->paren_conn->secret,
+				 sess->paren_conn->secret_len);
 	if (pack == 0) {
 		log_session(log_error, sess, "impossible to send ICCN:"
 			    " packet allocation failed\n");
@@ -1860,7 +1870,8 @@ static int l2tp_send_OCRQ(struct l2tp_sess_t *sess)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Outgoing_Call_Request,
 				 &sess->paren_conn->peer_addr, sess->hide_avps,
-				 conf_secret, conf_secret_len);
+				 sess->paren_conn->secret,
+				 sess->paren_conn->secret_len);
 	if (!pack) {
 		log_session(log_error, sess, "impossible to send OCRQ:"
 			    " packet allocation failed\n");
@@ -1925,7 +1936,8 @@ static int l2tp_send_OCRP(struct l2tp_sess_t *sess)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Outgoing_Call_Reply,
 				 &sess->paren_conn->peer_addr, sess->hide_avps,
-				 conf_secret, conf_secret_len);
+				 sess->paren_conn->secret,
+				 sess->paren_conn->secret_len);
 	if (pack == NULL) {
 		log_session(log_error, sess, "impossible to send OCRP:"
 			    " packet allocation failed\n");
@@ -1960,7 +1972,8 @@ static int l2tp_send_OCCN(struct l2tp_sess_t *sess)
 
 	pack = l2tp_packet_alloc(2, Message_Type_Outgoing_Call_Connected,
 				 &sess->paren_conn->peer_addr, sess->hide_avps,
-				 conf_secret, conf_secret_len);
+				 sess->paren_conn->secret,
+				 sess->paren_conn->secret_len);
 	if (pack == NULL) {
 		log_session(log_error, sess, "impossible to send OCCN:"
 			    " packet allocation failed\n");
@@ -2098,6 +2111,18 @@ static int l2tp_recv_SCCRQ(const struct l2tp_serv_t *serv,
 		}
 		tid = conn->tid;
 
+		if (conf_secret) {
+			conn->secret = _strdup(conf_secret);
+			if (conn->secret == NULL) {
+				log_error("l2tp: impossible to handle SCCRQ from %s:"
+					  " secret allocation failed\n",
+					  src_addr);
+				l2tp_tunnel_free(conn);
+				return -1;
+			}
+			conn->secret_len = strlen(conn->secret);
+		}
+
 		if (l2tp_tunnel_storechall(conn, challenge) < 0) {
 			log_error("l2tp: impossible to handle SCCRQ from %s:"
 				  " storing challenge failed\n", src_addr);
@@ -3275,7 +3300,7 @@ static int l2tp_conn_read(struct triton_md_handler_t *h)
 
 	while (1) {
 		res = l2tp_recv(h->fd, &pack, NULL,
-				conf_secret, conf_secret_len);
+				conn->secret, conn->secret_len);
 		if (res) {
 			if (res == -2) {
 				log_tunnel(log_info1, conn,
@@ -3696,6 +3721,7 @@ static int l2tp_create_tunnel_exec(const char *cmd, char * const *fields,
 		.sin_addr = { htonl(INADDR_ANY) }
 	};
 	const char *opt = NULL;
+	const char *secret = conf_secret;
 	int peer_indx = -1;
 	int host_indx = -1;
 	int lns_mode = 0;
@@ -3763,6 +3789,9 @@ static int l2tp_create_tunnel_exec(const char *cmd, char * const *fields,
 		} else if (strcmp("hide-avps", fields[indx]) == 0) {
 			++indx;
 			hide_avps = atoi(fields[indx]) > 0;
+		} else if (strcmp("secret", fields[indx]) == 0) {
+			++indx;
+			secret = fields[indx];
 		} else {
 			cli_sendv(client, "invalid option: \"%s\"\r\n",
 				  fields[indx]);
@@ -3787,6 +3816,16 @@ static int l2tp_create_tunnel_exec(const char *cmd, char * const *fields,
 	}
 	tid = conn->tid;
 
+	if (secret) {
+		conn->secret = _strdup(secret);
+		if (conn->secret == NULL) {
+			cli_sendv(client, "secret allocation failed\r\n");
+			l2tp_tunnel_free(conn);
+			return CLI_CMD_FAILED;
+		}
+		conn->secret_len = strlen(conn->secret);
+	}
+
 	if (l2tp_tunnel_start(conn, l2tp_send_SCCRQ, &peer) < 0) {
 		cli_send(client, "starting tunnel failed\r\n");
 		l2tp_tunnel_free(conn);