Automatically exchange ECDSA keys and upgrade to new authentication protocol.

[tinc] / src / protocol_auth.c

diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index d38814c..70062f3 100644 (file)
--- a/src/protocol_auth.c
+++ b/src/protocol_auth.c
@@ -43,8 +43,12 @@
 bool send_id(connection_t *c) {
        gettimeofday(&c->start, NULL);
 
+       int minor = myself->connection->protocol_minor;
+       if(c->config_tree && !read_ecdsa_public_key(c))
+               minor = 1;
+
        return send_request(c, "%d %s %d.%d", ID, myself->connection->name,
-                                               myself->connection->protocol_major, myself->connection->protocol_minor);
+                                               myself->connection->protocol_major, minor);
 }
 
 bool id_h(connection_t *c, char *request) {
@@ -110,6 +114,13 @@ bool id_h(connection_t *c, char *request) {
                                   c->name);
                        return false;
                }
+
+               if(c->protocol_minor >= 2)
+                       if(!read_ecdsa_public_key(c))
+                               return false;
+       } else {
+               if(!ecdsa_active(&c->ecdsa))
+                       c->protocol_minor = 1;
        }
 
        c->allow_request = METAKEY;
@@ -121,9 +132,6 @@ bool id_h(connection_t *c, char *request) {
 }
 
 bool send_metakey_ec(connection_t *c) {
-       if(!read_ecdsa_public_key(c))
-               return false;
-
        logger(LOG_DEBUG, "Sending ECDH metakey to %s", c->name);
 
        size_t siglen = ecdsa_size(&myself->connection->ecdsa);
@@ -149,11 +157,6 @@ bool send_metakey_ec(connection_t *c) {
 }
 
 bool send_metakey(connection_t *c) {
-       size_t len = rsa_size(&c->rsa);
-       char key[len];
-       char enckey[len];
-       char hexkey[2 * len + 1];
-
        if(!read_rsa_public_key(c))
                return false;
 
@@ -163,6 +166,11 @@ bool send_metakey(connection_t *c) {
        if(!digest_open_sha1(&c->outdigest, -1))
                return false;
 
+       size_t len = rsa_size(&c->rsa);
+       char key[len];
+       char enckey[len];
+       char hexkey[2 * len + 1];
+
        /* Create a random key */
 
        randomize(key, len);
@@ -451,7 +459,24 @@ bool chal_reply_h(connection_t *c, char *request) {
        return send_ack(c);
 }
 
+static bool send_upgrade(connection_t *c) {
+       /* Special case when protocol_minor is 1: the other end is ECDSA capable,
+        * but doesn't know our key yet. So send it now. */
+
+       char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
+
+       if(!pubkey)
+               return false;
+
+       bool result = send_request(c, "%d %s", ACK, pubkey);
+       free(pubkey);
+       return result;
+}
+
 bool send_ack(connection_t *c) {
+       if(c->protocol_minor == 1)
+               return send_upgrade(c);
+
        /* ACK message contains rest of the information the other end needs
           to create node_t and edge_t structures. */
 
@@ -516,7 +541,29 @@ static void send_everything(connection_t *c) {
        }
 }
 
+static bool upgrade_h(connection_t *c, char *request) {
+       char pubkey[MAX_STRING_SIZE];
+
+       if(sscanf(request, "%*d " MAX_STRING, pubkey) != 1) {
+               logger(LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name, c->hostname);
+               return false;
+       }
+
+       if(ecdsa_active(&c->ecdsa) || read_ecdsa_public_key(c)) {
+               logger(LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
+               return false;
+       }
+
+       logger(LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
+       append_connection_config(c, "ECDSAPublicKey", pubkey);
+       c->allow_request = TERMREQ;
+       return send_termreq(c);
+}
+
 bool ack_h(connection_t *c, char *request) {
+       if(c->protocol_minor == 1)
+               return upgrade_h(c, request);
+
        char hisport[MAX_STRING_SIZE];
        char *hisaddress;
        int weight, mtu;