/*
protocol_key.c -- handle the meta-protocol, key exchange
Copyright (C) 1999-2005 Ivo Timmermans,
- 2000-2010 Guus Sliepen <guus@tinc-vpn.org>
+ 2000-2011 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 "cipher.h"
#include "connection.h"
#include "crypto.h"
+#include "ecdh.h"
#include "logger.h"
#include "net.h"
#include "netutl.h"
#include "node.h"
+#include "prf.h"
#include "protocol.h"
#include "utils.h"
#include "xalloc.h"
static bool mykeyused = false;
-void send_key_changed() {
+void send_key_changed(void) {
splay_node_t *node;
connection_t *c;
- send_request(broadcast, "%d %x %s", KEY_CHANGED, rand(), myself->name);
+ send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name);
/* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
}
bool send_req_key(node_t *to) {
- return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
+ return send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, experimental ? 1 : 0);
}
bool req_key_h(connection_t *c, char *request) {
char from_name[MAX_STRING_SIZE];
char to_name[MAX_STRING_SIZE];
node_t *from, *to;
+ int kx_version = 0;
- if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING, from_name, to_name) != 2) {
+ if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &kx_version) < 2) {
logger(LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
c->hostname);
return false;
/* Check if this key request is for us */
if(to == myself) { /* Yes, send our own key back */
-
+ if(experimental && kx_version >= 1) {
+ logger(LOG_DEBUG, "Got ECDH key request from %s", from->name);
+ from->status.ecdh = true;
+ }
send_ans_key(from);
} else {
if(tunnelserver)
return true;
}
+bool send_ans_key_ecdh(node_t *to) {
+ int siglen = ecdsa_size(&myself->connection->ecdsa);
+ char key[(ECDH_SIZE + siglen) * 2 + 1];
+
+ if(!ecdh_generate_public(&to->ecdh, key))
+ return false;
+
+ if(!ecdsa_sign(&myself->connection->ecdsa, key, ECDH_SIZE, key + ECDH_SIZE))
+ return false;
+
+ b64encode(key, key, ECDH_SIZE + siglen);
+
+ char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
+
+ if(!pubkey)
+ return false;
+
+ int result = send_request(to->nexthop->connection, "%d %s %s ECDH:%s:%s %d %d %zu %d", ANS_KEY,
+ myself->name, to->name, key, pubkey,
+ cipher_get_nid(&myself->incipher),
+ digest_get_nid(&myself->indigest),
+ digest_length(&myself->indigest),
+ myself->incompression);
+
+ free(pubkey);
+ return result;
+}
+
bool send_ans_key(node_t *to) {
+ if(experimental && to->status.ecdh)
+ return send_ans_key_ecdh(to);
+
size_t keylen = cipher_keylength(&myself->incipher);
char key[keylen * 2 + 1];
to->incompression = myself->incompression;
randomize(key, keylen);
- cipher_set_key(&to->incipher, key, true);
+ cipher_set_key(&to->incipher, key, false);
digest_set_key(&to->indigest, key, keylen);
bin2hex(key, key, keylen);
- key[keylen * 2] = '\0';
// Reset sequence number and late packet window
mykeyused = true;
to->received_seqno = 0;
- memset(to->late, 0, sizeof(to->late));
+ if(replaywin) memset(to->late, 0, replaywin);
return send_request(to->nexthop->connection, "%d %s %s %s %d %d %zu %d", ANS_KEY,
myself->name, to->name, key,
int cipher, digest, maclength, compression, keylen;
node_t *from, *to;
- if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d",
+ if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
from_name, to_name, key, &cipher, &digest, &maclength,
&compression, address, port) < 7) {
logger(LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
return true;
}
+ if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
+ char *address, *port;
+ ifdebug(PROTOCOL) logger(LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
+ sockaddr2str(&from->address, &address, &port);
+ send_request(to->nexthop->connection, "%s %s %s", request, address, port);
+ free(address);
+ free(port);
+ return true;
+ }
+
return send_request(to->nexthop->connection, "%s", request);
}
return false;
}
- keylen = strlen(key) / 2;
-
- if(keylen != cipher_keylength(&from->outcipher)) {
- logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
- return false;
- }
-
if(!digest_open_by_nid(&from->outdigest, digest, maclength)) {
logger(LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
return false;
logger(LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
return true;
}
-
+
from->outcompression = compression;
- /* Update our copy of the origin's packet key */
+ /* ECDH or old-style key exchange? */
+
+ if(experimental && !strncmp(key, "ECDH:", 5)) {
+ char *pubkey = strchr(key + 5, ':');
+ if(pubkey)
+ *pubkey++ = 0;
+
+ /* Check if we already have an ECDSA public key for this node.
+ * If not, use the one from the key exchange, and store it. */
+
+ if(!node_read_ecdsa_public_key(from)) {
+ if(!pubkey) {
+ logger(LOG_ERR, "No ECDSA public key known for %s (%s), cannot verify ECDH key exchange!", from->name, from->hostname);
+ return true;
+ }
+
+ if(!ecdsa_set_base64_public_key(&from->ecdsa, pubkey))
+ return true;
+
+ append_config_file(from->name, "ECDSAPublicKey", pubkey);
+ }
- hex2bin(key, key, keylen);
- cipher_set_key(&from->outcipher, key, false);
- digest_set_key(&from->outdigest, key, keylen);
+ int siglen = ecdsa_size(&from->ecdsa);
+ int keylen = b64decode(key + 5, key + 5, sizeof key - 5);
+
+ if(keylen != ECDH_SIZE + siglen) {
+ logger(LOG_ERR, "Node %s (%s) uses wrong keylength! %d != %d", from->name, from->hostname, keylen, ECDH_SIZE + siglen);
+ return true;
+ }
+
+ if(ECDH_SHARED_SIZE < cipher_keylength(&from->outcipher)) {
+ logger(LOG_ERR, "ECDH key too short for cipher of %s!", from->name);
+ return true;
+ }
+
+ if(!ecdsa_verify(&from->ecdsa, key + 5, ECDH_SIZE, key + 5 + ECDH_SIZE)) {
+ logger(LOG_ERR, "Possible intruder %s (%s): %s", from->name, from->hostname, "invalid ECDSA signature");
+ return true;
+ }
+
+ if(!from->ecdh) {
+ from->status.ecdh = true;
+ if(!send_ans_key(from))
+ return true;
+ }
+
+ char shared[ECDH_SHARED_SIZE * 2 + 1];
+
+ if(!ecdh_compute_shared(&from->ecdh, key + 5, shared))
+ return true;
+
+ /* Update our crypto end */
+
+ size_t mykeylen = cipher_keylength(&myself->incipher);
+ size_t hiskeylen = cipher_keylength(&from->outcipher);
+
+ char *mykey;
+ char *hiskey;
+ char *seed;
+
+ if(strcmp(myself->name, from->name) < 0) {
+ mykey = key;
+ hiskey = key + mykeylen * 2;
+ xasprintf(&seed, "tinc UDP key expansion %s %s", myself->name, from->name);
+ } else {
+ mykey = key + hiskeylen * 2;
+ hiskey = key;
+ xasprintf(&seed, "tinc UDP key expansion %s %s", from->name, myself->name);
+ }
+
+ if(!prf(shared, ECDH_SHARED_SIZE, seed, strlen(seed), key, hiskeylen * 2 + mykeylen * 2))
+ return true;
+
+ free(seed);
+
+ cipher_open_by_nid(&from->incipher, cipher_get_nid(&myself->incipher));
+ digest_open_by_nid(&from->indigest, digest_get_nid(&myself->indigest), digest_length(&myself->indigest));
+ from->incompression = myself->incompression;
+
+ cipher_set_key(&from->incipher, mykey, false);
+ digest_set_key(&from->indigest, mykey + mykeylen, mykeylen);
+
+ cipher_set_key(&from->outcipher, hiskey, true);
+ digest_set_key(&from->outdigest, hiskey + hiskeylen, hiskeylen);
+
+ // Reset sequence number and late packet window
+ mykeyused = true;
+ from->received_seqno = 0;
+ if(replaywin)
+ memset(from->late, 0, replaywin);
+
+ if(strcmp(myself->name, from->name) < 0)
+ memmove(key, key + mykeylen * 2, hiskeylen * 2);
+ } else {
+ keylen = hex2bin(key, key, sizeof key);
+
+ if(keylen != cipher_keylength(&from->outcipher)) {
+ logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
+ return true;
+ }
+
+ /* Update our copy of the origin's packet key */
+
+ cipher_set_key(&from->outcipher, key, true);
+ digest_set_key(&from->outdigest, key, keylen);
+ }
from->status.validkey = true;
from->sent_seqno = 0;
update_node_udp(from, &sa);
}
- if(from->options & OPTION_PMTU_DISCOVERY && !from->mtuprobes)
+ if(from->options & OPTION_PMTU_DISCOVERY)
send_mtu_probe(from);
return true;
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