Prevent SPTPS key regeneration packets from entering an UDP relay path.

[tinc] / src / net_packet.c

diff --git a/src/net_packet.c b/src/net_packet.c
index 1fdc0fe..92a3eb5 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -260,7 +260,7 @@ static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
        if(!n->status.validkey_in || !digest_active(n->indigest) || inpkt->len < sizeof(seqno_t) + digest_length(n->indigest))
                return false;
 
-       return digest_verify(n->indigest, SEQNO(inpkt), inpkt->len - digest_length(n->indigest), DATA(inpkt) + inpkt->len - digest_length(n->indigest));
+       return digest_verify(n->indigest, inpkt->data, inpkt->len - digest_length(n->indigest), inpkt->data + inpkt->len - digest_length(n->indigest));
 #endif
 }
 
@@ -735,7 +735,7 @@ bool send_sptps_data(node_t *to, node_t *from, int type, const void *data, size_
        /* Send it via TCP if it is a handshake packet, TCPOnly is in use, this is a relay packet that the other node cannot understand, or this packet is larger than the MTU. */
 
        if(type == SPTPS_HANDSHAKE || tcponly || (!direct && !relay_supported) || (type != PKT_PROBE && (len - SPTPS_DATAGRAM_OVERHEAD) > relay->minmtu)) {
-               if((from != myself || to->status.validkey) && (to->nexthop->connection->options >> 24) >= 7) {
+               if(type != SPTPS_HANDSHAKE && (to->nexthop->connection->options >> 24) >= 7) {
                        char buf[len + sizeof to->id + sizeof from->id]; char* buf_ptr = buf;
                        memcpy(buf_ptr, &to->id, sizeof to->id); buf_ptr += sizeof to->id;
                        memcpy(buf_ptr, &from->id, sizeof from->id); buf_ptr += sizeof from->id;
@@ -746,9 +746,10 @@ bool send_sptps_data(node_t *to, node_t *from, int type, const void *data, size_
 
                char buf[len * 4 / 3 + 5];
                b64encode(data, buf, len);
-               /* If no valid key is known yet, send the packets using ANS_KEY requests,
-                  to ensure we get to learn the reflexive UDP address. */
-               if(from == myself && !to->status.validkey) {
+               /* If this is a handshake packet, use ANS_KEY instead of REQ_KEY, for two reasons:
+                   - We don't want intermediate nodes to switch to UDP to relay these packets;
+                   - ANS_KEY allows us to learn the reflexive UDP address. */
+               if(type == SPTPS_HANDSHAKE) {
                        to->incompression = myself->incompression;
                        return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, from->name, to->name, buf, to->incompression);
                } else {