Applied Martin Kihlgren's IdentityGenerosity patch,

[tinc] / src / net_packet.c

diff --git a/src/net_packet.c b/src/net_packet.c
index 8b49b25..ae5a840 100644 (file)
--- 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 1.1.2.47 2003/12/22 11:04:16 guus Exp $
+    $Id: net_packet.c,v 1.1.2.49 2003/12/27 16:32:52 guus Exp $
 */
 
 #include "system.h"
@@ -35,6 +35,7 @@
 #include "conf.h"
 #include "connection.h"
 #include "device.h"
+#include "ethernet.h"
 #include "event.h"
 #include "graph.h"
 #include "list.h"
@@ -53,6 +54,7 @@
 
 int keylifetime = 0;
 int keyexpires = 0;
+bool strictsource = true;
 EVP_CIPHER_CTX packet_ctx;
 static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS];
 
@@ -166,6 +168,25 @@ static void receive_packet(node_t *n, vpn_packet_t *packet)
        route(n, packet);
 }
 
+static bool authenticate_udppacket(node_t *n, vpn_packet_t *inpkt) {
+       char hmac[EVP_MAX_MD_SIZE];
+
+       if(inpkt->len < sizeof(inpkt->seqno) + (myself->digest ? myself->maclength : 0))
+               return false;
+
+       /* Check the message authentication code */
+
+       if(myself->digest && myself->maclength) {
+               HMAC(myself->digest, myself->key, myself->keylength,
+                        (char *) &inpkt->seqno, inpkt->len - myself->maclength, hmac, NULL);
+
+               if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len - myself->maclength, myself->maclength))
+                       return false;
+       }
+
+       return true;
+}
+
 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
 {
        vpn_packet_t pkt1, pkt2;
@@ -173,32 +194,17 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
        int nextpkt = 0;
        vpn_packet_t *outpkt = pkt[0];
        int outlen, outpad;
-       char hmac[EVP_MAX_MD_SIZE];
        int i;
 
        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);
+       if(!authenticate_udppacket(n, inpkt)) {
+               ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
+                                          n->name, n->hostname);
                return;
        }
 
-       /* Check the message authentication code */
-
-       if(myself->digest && myself->maclength) {
-               inpkt->len -= myself->maclength;
-               HMAC(myself->digest, myself->key, myself->keylength,
-                        (char *) &inpkt->seqno, inpkt->len, hmac, NULL);
-
-               if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, myself->maclength)) {
-                       ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got unauthenticated packet from %s (%s)"),
-                                          n->name, n->hostname);
-                       return;
-               }
-       }
+       inpkt->len -= myself->digest ? myself->maclength : 0;
 
        /* Decrypt the packet */
 
@@ -352,7 +358,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
                                || !EVP_EncryptFinal_ex(&n->packet_ctx, (char *) &outpkt->seqno + outlen, &outpad)) {
                        ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s): %s"),
                                                n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
-                       return;
+                       goto end;
                }
 
                outpkt->len = outlen + outpad;
@@ -389,16 +395,16 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
 #endif
 
        if((sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, &(n->address.sa), SALEN(n->address.sa))) < 0) {
-               logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
                if(errno == EMSGSIZE) {
                        if(n->maxmtu >= origlen)
                                n->maxmtu = origlen - 1;
                        if(n->mtu >= origlen)
                                n->mtu = origlen - 1;
-               }
-               return;
+               } else
+                       logger(LOG_ERR, _("Error sending packet to %s (%s): %s"), n->name, n->hostname, strerror(errno));
        }
 
+end:
        inpkt->len = origlen;
 }
 
@@ -412,6 +418,8 @@ void send_packet(const node_t *n, vpn_packet_t *packet)
        cp();
 
        if(n == myself) {
+               if(overwrite_mac)
+                        memcpy(packet->data, mymac.x, ETH_ALEN);
                write_packet(packet);
                return;
        }
@@ -480,6 +488,7 @@ void handle_incoming_vpn_data(int sock)
        sockaddr_t from;
        socklen_t fromlen = sizeof(from);
        node_t *n;
+       static time_t lasttime = 0;
 
        cp();
 
@@ -494,10 +503,25 @@ void handle_incoming_vpn_data(int sock)
 
        n = lookup_node_udp(&from);
 
+       if(!n && !strictsource && myself->digest && myself->maclength && lasttime != now) {
+               avl_node_t *node;
+
+               lasttime = now;
+
+               for(node = node_tree->head; node; node = node->next) {
+                       n = node->data;
+
+                       if(authenticate_udppacket(n, &pkt)) {
+                               update_node_address(n, &from);
+                               logger(LOG_DEBUG, _("Updated address of node %s to %s"), n->name, n->hostname);
+                               break;
+                       }
+               }
+       }
+
        if(!n) {
                hostname = sockaddr2hostname(&from);
-               logger(LOG_WARNING, _("Received UDP packet from unknown source %s"),
-                          hostname);
+               logger(LOG_WARNING, _("Received UDP packet from unknown source %s"), hostname);
                free(hostname);
                return;
        }