/*
protocol_key.c -- handle the meta-protocol, key exchange
Copyright (C) 1999-2005 Ivo Timmermans,
- 2000-2011 Guus Sliepen <guus@tinc-vpn.org>
+ 2000-2012 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
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 key_changed_h(connection_t *c, char *request) {
+bool key_changed_h(connection_t *c, const char *request) {
char name[MAX_STRING_SIZE];
node_t *n;
if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
- logger(LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
c->name, c->hostname);
return false;
}
n = lookup_node(name);
if(!n) {
- logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
"KEY_CHANGED", c->name, c->hostname, name);
return true;
}
}
bool send_req_key(node_t *to) {
- return send_request(to->nexthop->connection, "%d %s %s 1", REQ_KEY, myself->name, to->name);
+ if(experimental && OPTION_VERSION(to->options) >= 2) {
+ if(!node_read_ecdsa_public_key(to))
+ send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, REQ_PUBKEY);
+ }
+ return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
+}
+
+/* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
+
+static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, int reqno) {
+ switch(reqno) {
+ case REQ_PUBKEY: {
+ char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
+ send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
+ free(pubkey);
+ return true;
+ }
+
+ case ANS_PUBKEY: {
+ if(node_read_ecdsa_public_key(from)) {
+ logger(DEBUG_ALWAYS, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
+ return true;
+ }
+
+ char pubkey[4096];
+ if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !ecdsa_set_base64_public_key(&from->ecdsa, pubkey)) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
+ return true;
+ }
+
+ logger(DEBUG_ALWAYS, LOG_INFO, "Learned ECDSA public key from %s (%s)", from->name, from->hostname);
+ append_config_file(from->name, "ECDSAPublicKey", pubkey);
+ return true;
+ }
+
+ default:
+ logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
+ return true;
+ }
}
-bool req_key_h(connection_t *c, char *request) {
+bool req_key_h(connection_t *c, const char *request) {
char from_name[MAX_STRING_SIZE];
char to_name[MAX_STRING_SIZE];
node_t *from, *to;
- int kx_version = 0;
+ int reqno = 0;
- 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,
+ if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
c->hostname);
return false;
}
if(!check_id(from_name) || !check_id(to_name)) {
- logger(LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
return false;
}
from = lookup_node(from_name);
if(!from) {
- logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
"REQ_KEY", c->name, c->hostname, from_name);
return true;
}
to = lookup_node(to_name);
if(!to) {
- logger(LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
"REQ_KEY", c->name, c->hostname, to_name);
return true;
}
/* Check if this key request is for us */
if(to == myself) { /* Yes, send our own key back */
- if(kx_version > 0) {
- logger(LOG_DEBUG, "Got ECDH key request from %s", from->name);
- from->status.ecdh = true;
- }
+ if(experimental && reqno)
+ return req_key_ext_h(c, request, from, reqno);
+
send_ans_key(from);
} else {
if(tunnelserver)
return true;
if(!to->status.reachable) {
- logger(LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
+ logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
"REQ_KEY", c->name, c->hostname, to_name);
return true;
}
}
bool send_ans_key_ecdh(node_t *to) {
- char key[ECDH_SIZE * 2 + 1];
+ int siglen = ecdsa_size(&myself->connection->ecdsa);
+ char key[(ECDH_SIZE + siglen) * 2 + 1];
- ecdh_generate_public(&to->ecdh, key);
+ if(!ecdh_generate_public(&to->ecdh, key))
+ return false;
+
+ if(!ecdsa_sign(&myself->connection->ecdsa, key, ECDH_SIZE, key + ECDH_SIZE))
+ return false;
- bin2hex(key, key, ECDH_SIZE);
- key[ECDH_SIZE * 2] = '\0';
+ b64encode(key, key, ECDH_SIZE + siglen);
- return send_request(to->nexthop->connection, "%d %s %s ECDH:%s %d %d %zu %d", ANS_KEY,
+ int result = send_request(to->nexthop->connection, "%d %s %s %s %d %d %zu %d", ANS_KEY,
myself->name, to->name, key,
cipher_get_nid(&myself->incipher),
digest_get_nid(&myself->indigest),
digest_length(&myself->indigest),
myself->incompression);
+
+ return result;
}
bool send_ans_key(node_t *to) {
- if(to->status.ecdh)
+ if(experimental && OPTION_VERSION(to->options) >= 2)
return send_ans_key_ecdh(to);
size_t keylen = cipher_keylength(&myself->incipher);
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->incompression);
}
-bool ans_key_h(connection_t *c, char *request) {
+bool ans_key_h(connection_t *c, const char *request) {
char from_name[MAX_STRING_SIZE];
char to_name[MAX_STRING_SIZE];
char key[MAX_STRING_SIZE];
int cipher, digest, maclength, compression, keylen;
node_t *from, *to;
- if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING" %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,
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
c->hostname);
return false;
}
if(!check_id(from_name) || !check_id(to_name)) {
- logger(LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
return false;
}
from = lookup_node(from_name);
if(!from) {
- logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
"ANS_KEY", c->name, c->hostname, from_name);
return true;
}
to = lookup_node(to_name);
if(!to) {
- logger(LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
"ANS_KEY", c->name, c->hostname, to_name);
return true;
}
return true;
if(!to->status.reachable) {
- logger(LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
+ logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
"ANS_KEY", c->name, c->hostname, to_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);
+ logger(DEBUG_PROTOCOL, 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);
/* Check and lookup cipher and digest algorithms */
if(!cipher_open_by_nid(&from->outcipher, cipher)) {
- logger(LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
+ logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", 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);
+ logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
return false;
}
if(maclength != digest_length(&from->outdigest)) {
- logger(LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
+ logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
return false;
}
if(compression < 0 || compression > 11) {
- logger(LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
+ logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
return true;
}
/* ECDH or old-style key exchange? */
- if(!strncmp(key, "ECDH:", 5)) {
- keylen = (strlen(key) - 5) / 2;
+ if(experimental && OPTION_VERSION(from->options) >= 2) {
+ /* Check if we already have an ECDSA public key for this node. */
+
+ if(!node_read_ecdsa_public_key(from)) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "No ECDSA public key known for %s (%s), cannot verify ECDH key exchange!", from->name, from->hostname);
+ return true;
+ }
+
+ int siglen = ecdsa_size(&from->ecdsa);
+ int keylen = b64decode(key, key, sizeof key);
- if(keylen != ECDH_SIZE) {
- logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
- return false;
+ if(keylen != ECDH_SIZE + siglen) {
+ logger(DEBUG_ALWAYS, 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 false;
+ logger(DEBUG_ALWAYS, LOG_ERR, "ECDH key too short for cipher of %s!", from->name);
+ return true;
+ }
+
+ if(!ecdsa_verify(&from->ecdsa, key, ECDH_SIZE, key + ECDH_SIZE)) {
+ logger(DEBUG_ALWAYS, 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 false;
+ if(!send_ans_key_ecdh(from))
+ return true;
}
char shared[ECDH_SHARED_SIZE * 2 + 1];
- char hex[ECDH_SHARED_SIZE * 2 + 1];
- hex2bin(key + 5, key + 5, keylen);
- if(!ecdh_compute_shared(&from->ecdh, key + 5, shared))
- return false;
+ if(!ecdh_compute_shared(&from->ecdh, key, shared))
+ return true;
/* Update our crypto end */
}
if(!prf(shared, ECDH_SHARED_SIZE, seed, strlen(seed), key, hiskeylen * 2 + mykeylen * 2))
- return false;
+ return true;
free(seed);
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, true);
+ cipher_set_key(&from->incipher, mykey, false);
digest_set_key(&from->indigest, mykey + mykeylen, mykeylen);
- cipher_set_key(&from->outcipher, hiskey, false);
+ cipher_set_key(&from->outcipher, hiskey, true);
digest_set_key(&from->outdigest, hiskey + hiskeylen, hiskeylen);
// Reset sequence number and late packet window
if(strcmp(myself->name, from->name) < 0)
memmove(key, key + mykeylen * 2, hiskeylen * 2);
} else {
- keylen = strlen(key) / 2;
- hex2bin(key, key, keylen);
+ 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 false;
+ logger(DEBUG_ALWAYS, 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, false);
+ cipher_set_key(&from->outcipher, key, true);
digest_set_key(&from->outdigest, key, keylen);
}
from->sent_seqno = 0;
if(*address && *port) {
- ifdebug(PROTOCOL) logger(LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
+ logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
sockaddr_t sa = str2sockaddr(address, port);
update_node_udp(from, &sa);
}
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