From 288d956728ab4d4aabe9bc59b87991420dbda151 Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@tinc-vpn.org>
Date: Tue, 23 Sep 2003 20:59:01 +0000
Subject: [PATCH] Check for short packets from the tun/tap device and from
 other tinc daemons.

---
 src/net_packet.c | 18 +++++++++++++-----
 src/route.c      | 13 ++++++++++++-
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/src/net_packet.c b/src/net_packet.c
index 43b8e7c..a989b09 100644
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -17,7 +17,7 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
-    $Id: net_packet.c,v 1.1.2.40 2003/08/28 21:05:10 guus Exp $
+    $Id: net_packet.c,v 1.1.2.41 2003/09/23 20:59:01 guus Exp $
 */
 
 #include "system.h"
@@ -118,6 +118,14 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 
 	cp();
 
+	/* Check packet length */
+
+	if(inpkt->len < sizeof(inpkt->seqno) + myself->maclength) {
+		ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got too short packet from %s (%s)"),
+					n->name, n->hostname);
+		return;
+	}
+
 	/* Check the message authentication code */
 
 	if(myself->digest && myself->maclength) {
@@ -189,6 +197,9 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 		inpkt = outpkt;
 	}
 
+	if(n->connection)
+		n->connection->last_ping_time = now;
+
 	receive_packet(n, inpkt);
 }
 
@@ -401,7 +412,7 @@ void handle_incoming_vpn_data(int sock)
 
 	pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
-	if(pkt.len <= 0) {
+	if(pkt.len < 0) {
 		logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
 		return;
 	}
@@ -418,8 +429,5 @@ void handle_incoming_vpn_data(int sock)
 		return;
 	}
 
-	if(n->connection)
-		n->connection->last_ping_time = now;
-
 	receive_udppacket(n, &pkt);
 }
diff --git a/src/route.c b/src/route.c
index 16d932d..ab6a453 100644
--- a/src/route.c
+++ b/src/route.c
@@ -17,7 +17,7 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
-    $Id: route.c,v 1.1.2.64 2003/08/28 21:05:11 guus Exp $
+    $Id: route.c,v 1.1.2.65 2003/09/23 20:59:01 guus Exp $
 */
 
 #include "system.h"
@@ -532,6 +532,11 @@ void route_outgoing(vpn_packet_t *packet)
 
 	cp();
 
+	if(packet->len < 64) {
+		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Read too short packet"));
+		return;
+	}
+
 	/* FIXME: multicast? */
 
 	switch (routing_mode) {
@@ -578,6 +583,12 @@ void route_outgoing(vpn_packet_t *packet)
 
 void route_incoming(node_t *source, vpn_packet_t *packet)
 {
+	if(packet->len < 64) {
+		ifdebug(TRAFFIC) logger(LOG_WARNING, _("Got too short packet from %s (%s)"),
+					source->name, source->hostname);
+		return;
+	}
+
 	switch (routing_mode) {
 		case RMODE_ROUTER:
 			{
-- 
2.25.1