Prevent oracle attacks in the legacy protocol (CVE-2018-16737, CVE-2018-16738)
[tinc] / src / protocol_auth.c
index 0904afd..9d61ab8 100644 (file)
@@ -1,7 +1,7 @@
 /*
     protocol_auth.c -- handle the meta-protocol, authentication
     Copyright (C) 1999-2005 Ivo Timmermans,
-                  2000-2014 Guus Sliepen <guus@tinc-vpn.org>
+                  2000-2017 Guus Sliepen <guus@tinc-vpn.org>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
 #include "utils.h"
 #include "xalloc.h"
 
+#include "ed25519/sha512.h"
+
+int invitation_lifetime;
 ecdsa_t *invitation_key = NULL;
 
 static bool send_proxyrequest(connection_t *c) {
        switch(proxytype) {
-               case PROXY_HTTP: {
-                       char *host;
-                       char *port;
-
-                       sockaddr2str(&c->address, &host, &port);
-                       send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
-                       free(host);
-                       free(port);
-                       return true;
+       case PROXY_HTTP: {
+               char *host;
+               char *port;
+
+               sockaddr2str(&c->address, &host, &port);
+               send_request(c, "CONNECT %s:%s HTTP/1.1\r\n\r", host, port);
+               free(host);
+               free(port);
+               return true;
+       }
+
+       case PROXY_SOCKS4: {
+               if(c->address.sa.sa_family != AF_INET) {
+                       logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
+                       return false;
                }
-               case PROXY_SOCKS4: {
-                       if(c->address.sa.sa_family != AF_INET) {
-                               logger(DEBUG_ALWAYS, LOG_ERR, "Cannot connect to an IPv6 host through a SOCKS 4 proxy!");
-                               return false;
-                       }
-                       char s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
-                       s4req[0] = 4;
-                       s4req[1] = 1;
-                       memcpy(s4req + 2, &c->address.in.sin_port, 2);
-                       memcpy(s4req + 4, &c->address.in.sin_addr, 4);
-                       if(proxyuser)
-                               memcpy(s4req + 8, proxyuser, strlen(proxyuser));
-                       s4req[sizeof s4req - 1] = 0;
-                       c->tcplen = 8;
-                       return send_meta(c, s4req, sizeof s4req);
+
+               char s4req[9 + (proxyuser ? strlen(proxyuser) : 0)];
+               s4req[0] = 4;
+               s4req[1] = 1;
+               memcpy(s4req + 2, &c->address.in.sin_port, 2);
+               memcpy(s4req + 4, &c->address.in.sin_addr, 4);
+
+               if(proxyuser) {
+                       memcpy(s4req + 8, proxyuser, strlen(proxyuser));
                }
-               case PROXY_SOCKS5: {
-                       int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
-                       c->tcplen = 2;
-                       if(proxypass)
-                               len += 3 + strlen(proxyuser) + strlen(proxypass);
-                       char s5req[len];
-                       int i = 0;
-                       s5req[i++] = 5;
-                       s5req[i++] = 1;
-                       if(proxypass) {
-                               s5req[i++] = 2;
-                               s5req[i++] = 1;
-                               s5req[i++] = strlen(proxyuser);
-                               memcpy(s5req + i, proxyuser, strlen(proxyuser));
-                               i += strlen(proxyuser);
-                               s5req[i++] = strlen(proxypass);
-                               memcpy(s5req + i, proxypass, strlen(proxypass));
-                               i += strlen(proxypass);
-                               c->tcplen += 2;
-                       } else {
-                               s5req[i++] = 0;
-                       }
-                       s5req[i++] = 5;
+
+               s4req[sizeof(s4req) - 1] = 0;
+               c->tcplen = 8;
+               return send_meta(c, s4req, sizeof(s4req));
+       }
+
+       case PROXY_SOCKS5: {
+               int len = 3 + 6 + (c->address.sa.sa_family == AF_INET ? 4 : 16);
+               c->tcplen = 2;
+
+               if(proxypass) {
+                       len += 3 + strlen(proxyuser) + strlen(proxypass);
+               }
+
+               char s5req[len];
+               int i = 0;
+               s5req[i++] = 5;
+               s5req[i++] = 1;
+
+               if(proxypass) {
+                       s5req[i++] = 2;
                        s5req[i++] = 1;
+                       s5req[i++] = strlen(proxyuser);
+                       memcpy(s5req + i, proxyuser, strlen(proxyuser));
+                       i += strlen(proxyuser);
+                       s5req[i++] = strlen(proxypass);
+                       memcpy(s5req + i, proxypass, strlen(proxypass));
+                       i += strlen(proxypass);
+                       c->tcplen += 2;
+               } else {
                        s5req[i++] = 0;
-                       if(c->address.sa.sa_family == AF_INET) {
-                               s5req[i++] = 1;
-                               memcpy(s5req + i, &c->address.in.sin_addr, 4);
-                               i += 4;
-                               memcpy(s5req + i, &c->address.in.sin_port, 2);
-                               i += 2;
-                               c->tcplen += 10;
-                       } else if(c->address.sa.sa_family == AF_INET6) {
-                               s5req[i++] = 3;
-                               memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
-                               i += 16;
-                               memcpy(s5req + i, &c->address.in6.sin6_port, 2);
-                               i += 2;
-                               c->tcplen += 22;
-                       } else {
-                               logger(DEBUG_ALWAYS, LOG_ERR, "Address family %hx not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
-                               return false;
-                       }
-                       if(i > len)
-                               abort();
-                       return send_meta(c, s5req, sizeof s5req);
                }
-               case PROXY_SOCKS4A:
-                       logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
-                       return false;
-               case PROXY_EXEC:
-                       return true;
-               default:
-                       logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
+
+               s5req[i++] = 5;
+               s5req[i++] = 1;
+               s5req[i++] = 0;
+
+               if(c->address.sa.sa_family == AF_INET) {
+                       s5req[i++] = 1;
+                       memcpy(s5req + i, &c->address.in.sin_addr, 4);
+                       i += 4;
+                       memcpy(s5req + i, &c->address.in.sin_port, 2);
+                       i += 2;
+                       c->tcplen += 10;
+               } else if(c->address.sa.sa_family == AF_INET6) {
+                       s5req[i++] = 3;
+                       memcpy(s5req + i, &c->address.in6.sin6_addr, 16);
+                       i += 16;
+                       memcpy(s5req + i, &c->address.in6.sin6_port, 2);
+                       i += 2;
+                       c->tcplen += 22;
+               } else {
+                       logger(DEBUG_ALWAYS, LOG_ERR, "Address family %x not supported for SOCKS 5 proxies!", c->address.sa.sa_family);
                        return false;
+               }
+
+               if(i > len) {
+                       abort();
+               }
+
+               return send_meta(c, s5req, sizeof(s5req));
+       }
+
+       case PROXY_SOCKS4A:
+               logger(DEBUG_ALWAYS, LOG_ERR, "Proxy type not implemented yet");
+               return false;
+
+       case PROXY_EXEC:
+               return true;
+
+       default:
+               logger(DEBUG_ALWAYS, LOG_ERR, "Unknown proxy type");
+               return false;
        }
 }
 
@@ -139,15 +160,17 @@ bool send_id(connection_t *c) {
        int minor = 0;
 
        if(experimental) {
-               if(c->outgoing && !read_ecdsa_public_key(c))
+               if(c->outgoing && !read_ecdsa_public_key(c)) {
                        minor = 1;
-               else
+               } else {
                        minor = myself->connection->protocol_minor;
+               }
        }
 
        if(proxytype && c->outgoing)
-               if(!send_proxyrequest(c))
+               if(!send_proxyrequest(c)) {
                        return false;
+               }
 
        return send_request(c, "%d %s %d.%d", ID, myself->connection->name, myself->connection->protocol_major, minor);
 }
@@ -160,85 +183,99 @@ static bool finalize_invitation(connection_t *c, const char *data, uint16_t len)
 
        // Create a new host config file
        char filename[PATH_MAX];
-       snprintf(filename, sizeof filename, "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
+       snprintf(filename, sizeof(filename), "%s" SLASH "hosts" SLASH "%s", confbase, c->name);
+
        if(!access(filename, F_OK)) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Host config file for %s (%s) already exists!\n", c->name, c->hostname);
                return false;
        }
 
        FILE *f = fopen(filename, "w");
+
        if(!f) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to create %s: %s\n", filename, strerror(errno));
                return false;
        }
 
-       fprintf(f, "ECDSAPublicKey = %s\n", data);
+       fprintf(f, "Ed25519PublicKey = %s\n", data);
        fclose(f);
 
-       logger(DEBUG_CONNECTIONS, LOG_INFO, "Key succesfully received from %s (%s)", c->name, c->hostname);
+       logger(DEBUG_CONNECTIONS, LOG_INFO, "Key successfully received from %s (%s)", c->name, c->hostname);
 
        // Call invitation-accepted script
-       char *envp[7] = {NULL};
+       environment_t env;
        char *address, *port;
 
-       xasprintf(&envp[0], "NETNAME=%s", netname ? : "");
-        xasprintf(&envp[1], "DEVICE=%s", device ? : "");
-        xasprintf(&envp[2], "INTERFACE=%s", iface ? : "");
-        xasprintf(&envp[3], "NODE=%s", c->name);
+       environment_init(&env);
+       environment_add(&env, "NODE=%s", c->name);
        sockaddr2str(&c->address, &address, &port);
-       xasprintf(&envp[4], "REMOTEADDRESS=%s", address);
-       xasprintf(&envp[5], "NAME=%s", myself->name);
+       environment_add(&env, "REMOTEADDRESS=%s", address);
+       environment_add(&env, "NAME=%s", myself->name);
 
-       execute_script("invitation-accepted", envp);
+       execute_script("invitation-accepted", &env);
 
-       for(int i = 0; envp[i] && i < 7; i++)
-               free(envp[i]);
+       environment_exit(&env);
 
        sptps_send_record(&c->sptps, 2, data, 0);
        return true;
 }
 
-static bool receive_invitation_sptps(void *handle, uint8_t type, const char *data, uint16_t len) {
+static bool receive_invitation_sptps(void *handle, uint8_t type, const void *data, uint16_t len) {
        connection_t *c = handle;
 
-       if(type == 128)
+       if(type == 128) {
                return true;
+       }
 
-       if(type == 1 && c->status.invitation_used)
+       if(type == 1 && c->status.invitation_used) {
                return finalize_invitation(c, data, len);
+       }
 
-       if(type != 0 || len != 18 || c->status.invitation_used)
+       if(type != 0 || len != 18 || c->status.invitation_used) {
                return false;
+       }
 
        // Recover the filename from the cookie and the key
-       digest_t *digest = digest_open_by_name("sha256", 18);
-       if(!digest)
-               abort();
        char *fingerprint = ecdsa_get_base64_public_key(invitation_key);
        char hashbuf[18 + strlen(fingerprint)];
-       char cookie[25];
+       char cookie[64];
        memcpy(hashbuf, data, 18);
-       memcpy(hashbuf + 18, fingerprint, sizeof hashbuf - 18);
-       digest_create(digest, hashbuf, sizeof hashbuf, cookie);
+       memcpy(hashbuf + 18, fingerprint, sizeof(hashbuf) - 18);
+       sha512(hashbuf, sizeof(hashbuf), cookie);
        b64encode_urlsafe(cookie, cookie, 18);
-       digest_close(digest);
        free(fingerprint);
 
        char filename[PATH_MAX], usedname[PATH_MAX];
-       snprintf(filename, sizeof filename, "%s" SLASH "invitations" SLASH "%s", confbase, cookie);
-       snprintf(usedname, sizeof usedname, "%s" SLASH "invitations" SLASH "%s.used", confbase, cookie);
+       snprintf(filename, sizeof(filename), "%s" SLASH "invitations" SLASH "%s", confbase, cookie);
+       snprintf(usedname, sizeof(usedname), "%s" SLASH "invitations" SLASH "%s.used", confbase, cookie);
 
        // Atomically rename the invitation file
        if(rename(filename, usedname)) {
-               if(errno == ENOENT)
+               if(errno == ENOENT) {
                        logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use non-existing invitation %s\n", c->hostname, cookie);
-               else
+               } else {
                        logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to rename invitation %s\n", cookie);
+               }
+
+               return false;
+       }
+
+       // Check the timestamp of the invitation
+       struct stat st;
+
+       if(stat(usedname, &st)) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Could not stat %s", usedname);
+               return false;
+       }
+
+       if(st.st_mtime + invitation_lifetime < now.tv_sec) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s tried to use expired invitation %s", c->hostname, cookie);
                return false;
        }
 
        // Open the renamed file
        FILE *f = fopen(usedname, "r");
+
        if(!f) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Error trying to open invitation %s\n", cookie);
                return false;
@@ -246,20 +283,24 @@ static bool receive_invitation_sptps(void *handle, uint8_t type, const char *dat
 
        // Read the new node's Name from the file
        char buf[1024];
-       fgets(buf, sizeof buf, f);
-       if(*buf)
+       fgets(buf, sizeof(buf), f);
+
+       if(*buf) {
                buf[strlen(buf) - 1] = 0;
+       }
 
        len = strcspn(buf, " \t=");
        char *name = buf + len;
        name += strspn(name, " \t");
+
        if(*name == '=') {
                name++;
                name += strspn(name, " \t");
        }
+
        buf[len] = 0;
 
-       if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name)) {
+       if(!*buf || !*name || strcasecmp(buf, "Name") || !check_id(name) || !strcmp(name, myself->name)) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Invalid invitation file %s\n", cookie);
                fclose(f);
                return false;
@@ -271,24 +312,27 @@ static bool receive_invitation_sptps(void *handle, uint8_t type, const char *dat
        // Send the node the contents of the invitation file
        rewind(f);
        size_t result;
-       while((result = fread(buf, 1, sizeof buf, f)))
+
+       while((result = fread(buf, 1, sizeof(buf), f))) {
                sptps_send_record(&c->sptps, 0, buf, result);
+       }
+
        sptps_send_record(&c->sptps, 1, buf, 0);
        fclose(f);
        unlink(usedname);
 
        c->status.invitation_used = true;
 
-       logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s succesfully sent to %s (%s)", cookie, c->name, c->hostname);
+       logger(DEBUG_CONNECTIONS, LOG_INFO, "Invitation %s successfully sent to %s (%s)", cookie, c->name, c->hostname);
        return true;
 }
 
 bool id_h(connection_t *c, const char *request) {
        char name[MAX_STRING_SIZE];
 
-       if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
+       if(sscanf(request, "%*d " MAX_STRING " %2d.%3d", name, &c->protocol_major, &c->protocol_minor) < 2) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
-                          c->hostname);
+                      c->hostname);
                return false;
        }
 
@@ -302,6 +346,10 @@ bool id_h(connection_t *c, const char *request) {
                free(c->name);
                c->name = xstrdup("<control>");
 
+               if(!c->outgoing) {
+                       send_id(c);
+               }
+
                return send_request(c, "%d %d %d", ACK, TINC_CTL_VERSION_CURRENT, getpid());
        }
 
@@ -312,6 +360,7 @@ bool id_h(connection_t *c, const char *request) {
                }
 
                c->ecdsa = ecdsa_set_base64_public_key(name + 1);
+
                if(!c->ecdsa) {
                        logger(DEBUG_ALWAYS, LOG_ERR, "Got bad invitation from %s", c->hostname);
                        return false;
@@ -319,10 +368,19 @@ bool id_h(connection_t *c, const char *request) {
 
                c->status.invitation = true;
                char *mykey = ecdsa_get_base64_public_key(invitation_key);
-               if(!mykey)
+
+               if(!mykey) {
                        return false;
-               if(!send_request(c, "%d %s", ACK, mykey))
+               }
+
+               if(!c->outgoing) {
+                       send_id(c);
+               }
+
+               if(!send_request(c, "%d %s", ACK, mykey)) {
                        return false;
+               }
+
                free(mykey);
 
                c->protocol_minor = 2;
@@ -332,9 +390,9 @@ bool id_h(connection_t *c, const char *request) {
 
        /* Check if identity is a valid name */
 
-       if(!check_id(name)) {
+       if(!check_id(name) || !strcmp(name, myself->name)) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
-                          c->hostname, "invalid name");
+                      c->hostname, "invalid name");
                return false;
        }
 
@@ -343,12 +401,14 @@ bool id_h(connection_t *c, const char *request) {
        if(c->outgoing) {
                if(strcmp(c->name, name)) {
                        logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
-                                  c->name);
+                              c->name);
                        return false;
                }
        } else {
-               if(c->name)
+               if(c->name) {
                        free(c->name);
+               }
+
                c->name = xstrdup(name);
        }
 
@@ -356,72 +416,117 @@ bool id_h(connection_t *c, const char *request) {
 
        if(c->protocol_major != myself->connection->protocol_major) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
-                       c->name, c->hostname, c->protocol_major, c->protocol_minor);
+                      c->name, c->hostname, c->protocol_major, c->protocol_minor);
                return false;
        }
 
        if(bypass_security) {
-               if(!c->config_tree)
+               if(!c->config_tree) {
                        init_configuration(&c->config_tree);
+               }
+
                c->allow_request = ACK;
+
+               if(!c->outgoing) {
+                       send_id(c);
+               }
+
                return send_ack(c);
        }
 
-       if(!experimental)
+       if(!experimental) {
                c->protocol_minor = 0;
+       }
 
        if(!c->config_tree) {
                init_configuration(&c->config_tree);
 
-               if(!read_host_config(c->config_tree, c->name)) {
+               if(!read_host_config(c->config_tree, c->name, false)) {
                        logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname, c->name);
                        return false;
                }
 
-               if(experimental)
-                       if(!read_ecdsa_public_key(c))
-                               return false;
-       } else {
-               if(c->protocol_minor && !ecdsa_active(c->ecdsa))
-                       c->protocol_minor = 1;
+               if(experimental) {
+                       read_ecdsa_public_key(c);
+               }
+
+               /* Ignore failures if no key known yet */
+       }
+
+       if(c->protocol_minor && !ecdsa_active(c->ecdsa)) {
+               c->protocol_minor = 1;
        }
 
-       /* Forbid version rollback for nodes whose ECDSA key we know */
+       /* Forbid version rollback for nodes whose Ed25519 key we know */
 
-       if(ecdsa_active(c->ecdsa) && c->protocol_minor < 2) {
+       if(ecdsa_active(c->ecdsa) && c->protocol_minor < 1) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Peer %s (%s) tries to roll back protocol version to %d.%d",
-                       c->name, c->hostname, c->protocol_major, c->protocol_minor);
+                      c->name, c->hostname, c->protocol_major, c->protocol_minor);
                return false;
        }
 
        c->allow_request = METAKEY;
 
+       if(!c->outgoing) {
+               send_id(c);
+       }
+
        if(c->protocol_minor >= 2) {
                c->allow_request = ACK;
                char label[25 + strlen(myself->name) + strlen(c->name)];
 
-               if(c->outgoing)
-                       snprintf(label, sizeof label, "tinc TCP key expansion %s %s", myself->name, c->name);
-               else
-                       snprintf(label, sizeof label, "tinc TCP key expansion %s %s", c->name, myself->name);
+               if(c->outgoing) {
+                       snprintf(label, sizeof(label), "tinc TCP key expansion %s %s", myself->name, c->name);
+               } else {
+                       snprintf(label, sizeof(label), "tinc TCP key expansion %s %s", c->name, myself->name);
+               }
 
-               return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof label, send_meta_sptps, receive_meta_sptps);
+               return sptps_start(&c->sptps, c, c->outgoing, false, myself->connection->ecdsa, c->ecdsa, label, sizeof(label), send_meta_sptps, receive_meta_sptps);
        } else {
                return send_metakey(c);
        }
 }
 
 bool send_metakey(connection_t *c) {
-       if(!read_rsa_public_key(c))
+#ifdef DISABLE_LEGACY
+       return false;
+#else
+
+       if(!myself->connection->rsa) {
+               logger(DEBUG_CONNECTIONS, LOG_ERR, "Peer %s (%s) uses legacy protocol which we don't support", c->name, c->hostname);
+               return false;
+       }
+
+       if(!read_rsa_public_key(c)) {
                return false;
+       }
+
+       /* We need to use a stream mode for the meta protocol. Use AES for this,
+          but try to match the key size with the one from the cipher selected
+          by Cipher.
+       */
+
+       int keylen = cipher_keylength(myself->incipher);
+
+       if(keylen <= 16) {
+               c->outcipher = cipher_open_by_name("aes-128-cfb");
+       } else if(keylen <= 24) {
+               c->outcipher = cipher_open_by_name("aes-192-cfb");
+       } else {
+               c->outcipher = cipher_open_by_name("aes-256-cfb");
+       }
 
-       if(!(c->outcipher = cipher_open_blowfish_ofb()))
+       if(!c) {
                return false;
+       }
+
+       c->outbudget = cipher_budget(c->outcipher);
 
-       if(!(c->outdigest = digest_open_sha1(-1)))
+       if(!(c->outdigest = digest_open_by_name("sha256", -1))) {
                return false;
+       }
 
-       size_t len = rsa_size(c->rsa);
+       const size_t len = rsa_size(c->rsa);
        char key[len];
        char enckey[len];
        char hexkey[2 * len + 1];
@@ -442,8 +547,9 @@ bool send_metakey(connection_t *c) {
 
        key[0] &= 0x7F;
 
-       if(!cipher_set_key_from_rsa(c->outcipher, key, len, true))
+       if(!cipher_set_key_from_rsa(c->outcipher, key, len, true)) {
                return false;
+       }
 
        if(debug_level >= DEBUG_SCARY_THINGS) {
                bin2hex(key, hexkey, len);
@@ -469,18 +575,27 @@ bool send_metakey(connection_t *c) {
        /* Send the meta key */
 
        bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
-                        cipher_get_nid(c->outcipher),
-                        digest_get_nid(c->outdigest), c->outmaclength,
-                        c->outcompression, hexkey);
+                                  cipher_get_nid(c->outcipher),
+                                  digest_get_nid(c->outdigest), c->outmaclength,
+                                  c->outcompression, hexkey);
 
        c->status.encryptout = true;
        return result;
+#endif
 }
 
 bool metakey_h(connection_t *c, const char *request) {
+#ifdef DISABLE_LEGACY
+       return false;
+#else
+
+       if(!myself->connection->rsa) {
+               return false;
+       }
+
        char hexkey[MAX_STRING_SIZE];
        int cipher, digest, maclength, compression;
-       size_t len = rsa_size(myself->connection->rsa);
+       const size_t len = rsa_size(myself->connection->rsa);
        char enckey[len];
        char key[len];
 
@@ -491,7 +606,7 @@ bool metakey_h(connection_t *c, const char *request) {
 
        /* Convert the challenge from hexadecimal back to binary */
 
-       int inlen = hex2bin(hexkey, enckey, sizeof enckey);
+       int inlen = hex2bin(hexkey, enckey, sizeof(enckey));
 
        /* Check if the length of the meta key is all right */
 
@@ -514,13 +629,25 @@ bool metakey_h(connection_t *c, const char *request) {
 
        /* Check and lookup cipher and digest algorithms */
 
-       if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
-               logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
+       if(cipher) {
+               if(!(c->incipher = cipher_open_by_nid(cipher)) || !cipher_set_key_from_rsa(c->incipher, key, len, false)) {
+                       logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
+                       return false;
+               }
+       } else {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "null cipher");
                return false;
        }
 
-       if(!(c->indigest = digest_open_by_nid(digest, -1))) {
-               logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
+       c->inbudget = cipher_budget(c->incipher);
+
+       if(digest) {
+               if(!(c->indigest = digest_open_by_nid(digest, -1))) {
+                       logger(DEBUG_ALWAYS, LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
+                       return false;
+               }
+       } else {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "null digest");
                return false;
        }
 
@@ -529,14 +656,17 @@ bool metakey_h(connection_t *c, const char *request) {
        c->allow_request = CHALLENGE;
 
        return send_challenge(c);
+#endif
 }
 
 bool send_challenge(connection_t *c) {
-       size_t len = rsa_size(c->rsa);
+#ifdef DISABLE_LEGACY
+       return false;
+#else
+       const size_t len = rsa_size(c->rsa);
        char buffer[len * 2 + 1];
 
-       if(!c->hischallenge)
-               c->hischallenge = xrealloc(c->hischallenge, len);
+       c->hischallenge = xrealloc(c->hischallenge, len);
 
        /* Copy random data to the buffer */
 
@@ -549,58 +679,90 @@ bool send_challenge(connection_t *c) {
        /* Send the challenge */
 
        return send_request(c, "%d %s", CHALLENGE, buffer);
+#endif
 }
 
 bool challenge_h(connection_t *c, const char *request) {
+#ifdef DISABLE_LEGACY
+       return false;
+#else
+
+       if(!myself->connection->rsa) {
+               return false;
+       }
+
        char buffer[MAX_STRING_SIZE];
-       size_t len = rsa_size(myself->connection->rsa);
-       size_t digestlen = digest_length(c->indigest);
-       char digest[digestlen];
+       const size_t len = rsa_size(myself->connection->rsa);
 
        if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
                return false;
        }
 
-       /* Convert the challenge from hexadecimal back to binary */
-
-       int inlen = hex2bin(buffer, buffer, sizeof buffer);
-
        /* Check if the length of the challenge is all right */
 
-       if(inlen != len) {
+       if(strlen(buffer) != (size_t)len * 2) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
                return false;
        }
 
+       c->mychallenge = xrealloc(c->mychallenge, len);
+
+       /* Convert the challenge from hexadecimal back to binary */
+
+       hex2bin(buffer, c->mychallenge, len);
+
+       /* The rest is done by send_chal_reply() */
+
+       c->allow_request = CHAL_REPLY;
+
+       if(c->outgoing) {
+               return send_chal_reply(c);
+       } else {
+               return true;
+       }
+
+#endif
+}
+
+bool send_chal_reply(connection_t *c) {
+       const size_t len = rsa_size(myself->connection->rsa);
+       size_t digestlen = digest_length(c->indigest);
+       char digest[digestlen * 2 + 1];
+
        /* Calculate the hash from the challenge we received */
 
-       if(!digest_create(c->indigest, buffer, len, digest))
+       if(!digest_create(c->indigest, c->mychallenge, len, digest)) {
                return false;
+       }
+
+       free(c->mychallenge);
+       c->mychallenge = NULL;
 
        /* Convert the hash to a hexadecimal formatted string */
 
-       bin2hex(digest, buffer, digestlen);
+       bin2hex(digest, digest, digestlen);
 
        /* Send the reply */
 
-       c->allow_request = CHAL_REPLY;
-
-       return send_request(c, "%d %s", CHAL_REPLY, buffer);
+       return send_request(c, "%d %s", CHAL_REPLY, digest);
 }
 
 bool chal_reply_h(connection_t *c, const char *request) {
+#ifdef DISABLE_LEGACY
+       return false;
+#else
        char hishash[MAX_STRING_SIZE];
 
        if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
-                          c->hostname);
+                      c->hostname);
                return false;
        }
 
        /* Convert the hash to binary format */
 
-       int inlen = hex2bin(hishash, hishash, sizeof hishash);
+       int inlen = hex2bin(hishash, hishash, sizeof(hishash));
 
        /* Check if the length of the hash is all right */
 
@@ -625,26 +787,37 @@ bool chal_reply_h(connection_t *c, const char *request) {
        c->hischallenge = NULL;
        c->allow_request = ACK;
 
+       if(!c->outgoing) {
+               send_chal_reply(c);
+       }
+
        return send_ack(c);
+#endif
 }
 
 static bool send_upgrade(connection_t *c) {
-       /* Special case when protocol_minor is 1: the other end is ECDSA capable,
+#ifdef DISABLE_LEGACY
+       return false;
+#else
+       /* Special case when protocol_minor is 1: the other end is Ed25519 capable,
         * but doesn't know our key yet. So send it now. */
 
        char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
 
-       if(!pubkey)
+       if(!pubkey) {
                return false;
+       }
 
        bool result = send_request(c, "%d %s", ACK, pubkey);
        free(pubkey);
        return result;
+#endif
 }
 
 bool send_ack(connection_t *c) {
-       if(c->protocol_minor == 1)
+       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. */
@@ -659,22 +832,28 @@ bool send_ack(connection_t *c) {
 
        /* Check some options */
 
-       if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
+       if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT) {
                c->options |= OPTION_INDIRECT;
+       }
 
-       if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
+       if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY) {
                c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
+       }
 
-       if(myself->options & OPTION_PMTU_DISCOVERY)
+       if(myself->options & OPTION_PMTU_DISCOVERY && !(c->options & OPTION_TCPONLY)) {
                c->options |= OPTION_PMTU_DISCOVERY;
+       }
 
        choice = myself->options & OPTION_CLAMP_MSS;
        get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
-       if(choice)
+
+       if(choice) {
                c->options |= OPTION_CLAMP_MSS;
+       }
 
-       if(!get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight))
+       if(!get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight)) {
                get_config_int(lookup_config(config_tree, "Weight"), &c->estimated_weight);
+       }
 
        return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, (c->options & 0xffffff) | (experimental ? (PROT_MINOR << 24) : 0));
 }
@@ -688,24 +867,27 @@ static void send_everything(connection_t *c) {
                        char pad[MAXBUFSIZE - MAXSIZE];
                } zeropkt;
 
-               memset(&zeropkt, 0, sizeof zeropkt);
+               memset(&zeropkt, 0, sizeof(zeropkt));
                zeropkt.pkt.len = MAXBUFSIZE;
                send_tcppacket(c, &zeropkt.pkt);
        }
 
        if(tunnelserver) {
-               for splay_each(subnet_t, s, myself->subnet_tree)
+               for splay_each(subnet_t, s, myself->subnet_tree) {
                        send_add_subnet(c, s);
+               }
 
                return;
        }
 
        for splay_each(node_t, n, node_tree) {
-               for splay_each(subnet_t, s, n->subnet_tree)
+               for splay_each(subnet_t, s, n->subnet_tree) {
                        send_add_subnet(c, s);
+               }
 
-               for splay_each(edge_t, e, n->edge_tree)
+               for splay_each(edge_t, e, n->edge_tree) {
                        send_add_edge(c, e);
+               }
        }
 }
 
@@ -718,22 +900,44 @@ static bool upgrade_h(connection_t *c, const char *request) {
        }
 
        if(ecdsa_active(c->ecdsa) || read_ecdsa_public_key(c)) {
-               logger(DEBUG_ALWAYS, LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
+               char *knownkey = ecdsa_get_base64_public_key(c->ecdsa);
+               bool different = strcmp(knownkey, pubkey);
+               free(knownkey);
+
+               if(different) {
+                       logger(DEBUG_ALWAYS, LOG_ERR, "Already have an Ed25519 public key from %s (%s) which is different from the one presented now!", c->name, c->hostname);
+                       return false;
+               }
+
+               logger(DEBUG_ALWAYS, LOG_INFO, "Already have Ed25519 public key from %s (%s), ignoring.", c->name, c->hostname);
+               c->allow_request = TERMREQ;
+               return send_termreq(c);
+       }
+
+       c->ecdsa = ecdsa_set_base64_public_key(pubkey);
+
+       if(!c->ecdsa) {
+               logger(DEBUG_ALWAYS, LOG_INFO, "Got bad Ed25519 public key from %s (%s), not upgrading.", c->name, c->hostname);
                return false;
        }
 
-       logger(DEBUG_ALWAYS, LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
-       append_config_file(c->name, "ECDSAPublicKey", pubkey);
+       logger(DEBUG_ALWAYS, LOG_INFO, "Got Ed25519 public key from %s (%s), upgrading!", c->name, c->hostname);
+       append_config_file(c->name, "Ed25519PublicKey", pubkey);
        c->allow_request = TERMREQ;
+
+       if(c->outgoing) {
+               c->outgoing->timeout = 0;
+       }
+
        return send_termreq(c);
 }
 
 bool ack_h(connection_t *c, const char *request) {
-       if(c->protocol_minor == 1)
+       if(c->protocol_minor == 1) {
                return upgrade_h(c, request);
+       }
 
        char hisport[MAX_STRING_SIZE];
-       char *hisaddress;
        int weight, mtu;
        uint32_t options;
        node_t *n;
@@ -741,7 +945,7 @@ bool ack_h(connection_t *c, const char *request) {
 
        if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
-                          c->hostname);
+                      c->hostname);
                return false;
        }
 
@@ -759,10 +963,11 @@ bool ack_h(connection_t *c, const char *request) {
                        logger(DEBUG_CONNECTIONS, LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
 
                        if(n->connection->outgoing) {
-                               if(c->outgoing)
+                               if(c->outgoing) {
                                        logger(DEBUG_ALWAYS, LOG_WARNING, "Two outgoing connections to the same node!");
-                               else
+                               } else {
                                        c->outgoing = n->connection->outgoing;
+                               }
 
                                n->connection->outgoing = NULL;
                        }
@@ -775,32 +980,36 @@ bool ack_h(connection_t *c, const char *request) {
 
        n->connection = c;
        c->node = n;
+
        if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
                c->options &= ~OPTION_PMTU_DISCOVERY;
                options &= ~OPTION_PMTU_DISCOVERY;
        }
+
        c->options |= options;
 
-       if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
+       if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu) {
                n->mtu = mtu;
+       }
 
-       if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
+       if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu) {
                n->mtu = mtu;
+       }
 
        if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
-               if(choice)
+               if(choice) {
                        c->options |= OPTION_CLAMP_MSS;
-               else
+               } else {
                        c->options &= ~OPTION_CLAMP_MSS;
+               }
        }
 
        /* Activate this connection */
 
        c->allow_request = ALL;
-       c->status.active = true;
 
        logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Connection with %s (%s) activated", c->name,
-                          c->hostname);
+              c->hostname);
 
        /* Send him everything we know */
 
@@ -811,9 +1020,18 @@ bool ack_h(connection_t *c, const char *request) {
        c->edge = new_edge();
        c->edge->from = myself;
        c->edge->to = n;
-       sockaddr2str(&c->address, &hisaddress, NULL);
-       c->edge->address = str2sockaddr(hisaddress, hisport);
-       free(hisaddress);
+       sockaddrcpy(&c->edge->address, &c->address);
+       sockaddr_setport(&c->edge->address, hisport);
+       sockaddr_t local_sa;
+       socklen_t local_salen = sizeof(local_sa);
+
+       if(getsockname(c->socket, &local_sa.sa, &local_salen) < 0) {
+               logger(DEBUG_ALWAYS, LOG_WARNING, "Could not get local socket address for connection with %s", c->name);
+       } else {
+               sockaddr_setport(&local_sa, myport);
+               c->edge->local_address = local_sa;
+       }
+
        c->edge->weight = (weight + c->estimated_weight) / 2;
        c->edge->connection = c;
        c->edge->options = c->options;
@@ -822,10 +1040,11 @@ bool ack_h(connection_t *c, const char *request) {
 
        /* Notify everyone of the new edge */
 
-       if(tunnelserver)
+       if(tunnelserver) {
                send_add_edge(c, c->edge);
-       else
+       } else {
                send_add_edge(everyone, c->edge);
+       }
 
        /* Run MST and SSSP algorithms */