/*
protocol_key.c -- handle the meta-protocol, key exchange
Copyright (C) 1999-2005 Ivo Timmermans,
- 2000-2012 Guus Sliepen <guus@tinc-vpn.org>
+ 2000-2014 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 "system.h"
-#include "splay_tree.h"
#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 "sptps.h"
#include "utils.h"
#include "xalloc.h"
static bool mykeyused = false;
void send_key_changed(void) {
- splay_node_t *node;
- connection_t *c;
-
+#ifndef DISABLE_LEGACY
send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name);
/* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
- for(node = connection_tree->head; node; node = node->next) {
- c = node->data;
- if(c->status.active && c->node && c->node->status.reachable)
+ for list_each(connection_t, c, connection_list)
+ if(c->edge && c->node && c->node->status.reachable && !c->node->status.sptps)
send_ans_key(c->node);
+#endif
+
+ /* Force key exchange for connections using SPTPS */
+
+ if(experimental) {
+ for splay_each(node_t, n, node_tree)
+ if(n->status.reachable && n->status.validkey && n->status.sptps)
+ sptps_force_kex(&n->sptps);
}
}
return true;
}
- n->status.validkey = false;
- n->last_req_key = 0;
+ if(!n->status.sptps) {
+ n->status.validkey = false;
+ n->last_req_key = 0;
+ }
/* Tell the others */
return true;
}
+static bool send_sptps_data_myself(void *handle, uint8_t type, const void *data, size_t len) {
+ return send_sptps_data(handle, myself, type, data, len);
+}
+
+static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
+ node_t *to = handle;
+ to->sptps.send_data = send_sptps_data_myself;
+ char buf[len * 4 / 3 + 5];
+ b64encode(data, buf, len);
+ return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_KEY, buf);
+}
+
bool send_req_key(node_t *to) {
- if(experimental && OPTION_VERSION(to->options) >= 2) {
- if(!node_read_ecdsa_public_key(to))
+ if(to->status.sptps) {
+ if(!node_read_ecdsa_public_key(to)) {
+ logger(DEBUG_PROTOCOL, LOG_DEBUG, "No Ed25519 key known for %s (%s)", to->name, to->hostname);
send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, REQ_PUBKEY);
+ return true;
+ }
+
+ char label[25 + strlen(myself->name) + strlen(to->name)];
+ snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name);
+ sptps_stop(&to->sptps);
+ to->status.validkey = false;
+ to->status.waitingforkey = true;
+ to->last_req_key = now.tv_sec;
+ to->incompression = myself->incompression;
+ return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof label, send_initial_sptps_data, receive_sptps_record);
}
+
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) {
+static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, node_t *to, int reqno) {
+ /* If this is a SPTPS packet, see if sending UDP info helps.
+ Note that we only do this if we're the destination or the static relay;
+ otherwise every hop would initiate its own UDP info message, resulting in elevated chatter. */
+ if((reqno == REQ_KEY || reqno == SPTPS_PACKET) && to->via == myself)
+ send_udp_info(myself, from);
+
+ if(reqno == SPTPS_PACKET) {
+ /* This is a SPTPS data packet. */
+
+ char buf[MAX_STRING_SIZE];
+ int len;
+ if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s) to %s (%s): %s", "SPTPS_PACKET", from->name, from->hostname, to->name, to->hostname, "invalid SPTPS data");
+ return true;
+ }
+
+ if(to != myself) {
+ /* We don't just forward the request, because we want to use UDP if it's available. */
+ send_sptps_data(to, from, 0, buf, len);
+ try_tx(to, true);
+ } else {
+ /* The packet is for us */
+ if(!sptps_receive_data(&from->sptps, buf, len)) {
+ /* Uh-oh. It might be that the tunnel is stuck in some corrupted state,
+ so let's restart SPTPS in case that helps. But don't do that too often
+ to prevent storms. */
+ if(from->last_req_key < now.tv_sec - 10) {
+ logger(DEBUG_PROTOCOL, LOG_ERR, "Failed to decode TCP packet from %s (%s), restarting SPTPS", from->name, from->hostname);
+ send_req_key(from);
+ }
+ return true;
+ }
+ send_mtu_info(myself, from, MTU);
+ }
+
+ return true;
+ }
+
+ /* Requests that are not SPTPS data packets are forwarded as-is. */
+
+ if (to != myself)
+ return send_request(to->nexthop->connection, "%s", request);
+
+ /* The request is for us */
+
switch(reqno) {
case REQ_PUBKEY: {
- char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
+ if(!node_read_ecdsa_public_key(from)) {
+ /* Request their key *before* we send our key back. Otherwise the first SPTPS packet from them will get dropped. */
+ logger(DEBUG_PROTOCOL, LOG_DEBUG, "Preemptively requesting Ed25519 key for %s (%s)", from->name, from->hostname);
+ send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, 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);
+ logger(DEBUG_PROTOCOL, 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)) {
+ char pubkey[MAX_STRING_SIZE];
+ if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(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);
+ logger(DEBUG_PROTOCOL, LOG_INFO, "Learned Ed25519 public key from %s (%s)", from->name, from->hostname);
+ append_config_file(from->name, "Ed25519PublicKey", pubkey);
+ return true;
+ }
+
+ case REQ_KEY: {
+ if(!node_read_ecdsa_public_key(from)) {
+ logger(DEBUG_PROTOCOL, LOG_DEBUG, "No Ed25519 key known for %s (%s)", from->name, from->hostname);
+ send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
+ return true;
+ }
+
+ if(from->sptps.label)
+ logger(DEBUG_ALWAYS, LOG_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
+
+ char buf[MAX_STRING_SIZE];
+ int len;
+
+ if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS_START", from->name, from->hostname, "invalid SPTPS data");
+ return true;
+ }
+
+ char label[25 + strlen(from->name) + strlen(myself->name)];
+ snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
+ sptps_stop(&from->sptps);
+ from->status.validkey = false;
+ from->status.waitingforkey = true;
+ from->last_req_key = now.tv_sec;
+ sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data_myself, receive_sptps_record);
+ sptps_receive_data(&from->sptps, buf, len);
+ send_mtu_info(myself, from, MTU);
return true;
}
/* Check if this key request is for us */
- if(to == myself) { /* Yes, send our own key back */
+ if(to == myself) { /* Yes */
+ /* Is this an extended REQ_KEY message? */
if(experimental && reqno)
- return req_key_ext_h(c, request, from, reqno);
+ return req_key_ext_h(c, request, from, to, reqno);
+ /* No, just send our key back */
send_ans_key(from);
} else {
if(tunnelserver)
return true;
if(!to->status.reachable) {
- logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
+ logger(DEBUG_PROTOCOL, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
"REQ_KEY", c->name, c->hostname, to_name);
return true;
}
+ /* Is this an extended REQ_KEY message? */
+ if(experimental && reqno)
+ return req_key_ext_h(c, request, from, to, reqno);
+
send_request(to->nexthop->connection, "%s", request);
}
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;
+bool send_ans_key(node_t *to) {
+ if(to->status.sptps)
+ abort();
- b64encode(key, key, ECDH_SIZE + siglen);
+#ifdef DISABLE_LEGACY
+ return false;
+#else
+ size_t keylen = myself->incipher ? cipher_keylength(myself->incipher) : 1;
+ char key[keylen * 2 + 1];
- int result = send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
- myself->name, to->name, key,
- cipher_get_nid(&myself->incipher),
- digest_get_nid(&myself->indigest),
- (int)digest_length(&myself->indigest),
- myself->incompression);
+ randomize(key, keylen);
- return result;
-}
+ cipher_close(to->incipher);
+ digest_close(to->indigest);
-bool send_ans_key(node_t *to) {
- if(experimental && OPTION_VERSION(to->options) >= 2)
- return send_ans_key_ecdh(to);
+ if(myself->incipher) {
+ to->incipher = cipher_open_by_nid(cipher_get_nid(myself->incipher));
+ if(!to->incipher)
+ abort();
+ if(!cipher_set_key(to->incipher, key, false))
+ abort();
+ }
- size_t keylen = cipher_keylength(&myself->incipher);
- char key[keylen * 2 + 1];
+ if(myself->indigest) {
+ to->indigest = digest_open_by_nid(digest_get_nid(myself->indigest), digest_length(myself->indigest));
+ if(!to->indigest)
+ abort();
+ if(!digest_set_key(to->indigest, key, keylen))
+ abort();
+ }
- cipher_open_by_nid(&to->incipher, cipher_get_nid(&myself->incipher));
- digest_open_by_nid(&to->indigest, digest_get_nid(&myself->indigest), digest_length(&myself->indigest));
to->incompression = myself->incompression;
- randomize(key, keylen);
- cipher_set_key(&to->incipher, key, false);
- digest_set_key(&to->indigest, key, keylen);
-
bin2hex(key, key, keylen);
// Reset sequence number and late packet window
mykeyused = true;
to->received_seqno = 0;
+ to->received = 0;
if(replaywin) memset(to->late, 0, replaywin);
+ to->status.validkey_in = true;
+
return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
myself->name, to->name, key,
- cipher_get_nid(&to->incipher),
- digest_get_nid(&to->indigest),
- (int)digest_length(&to->indigest),
+ cipher_get_nid(to->incipher),
+ digest_get_nid(to->indigest),
+ (int)digest_length(to->indigest),
to->incompression);
+#endif
}
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];
- char address[MAX_STRING_SIZE] = "";
- char port[MAX_STRING_SIZE] = "";
+ char address[MAX_STRING_SIZE] = "";
+ char port[MAX_STRING_SIZE] = "";
int cipher, digest, maclength, compression, keylen;
node_t *from, *to;
return send_request(to->nexthop->connection, "%s", request);
}
- /* Check and lookup cipher and digest algorithms */
-
- if(!cipher_open_by_nid(&from->outcipher, cipher)) {
- 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(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
- return false;
- }
-
- if(maclength != digest_length(&from->outdigest)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
- return false;
- }
+#ifndef DISABLE_LEGACY
+ /* Don't use key material until every check has passed. */
+ cipher_close(from->outcipher);
+ digest_close(from->outdigest);
+#endif
+ from->status.validkey = false;
if(compression < 0 || compression > 11) {
logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
from->outcompression = compression;
- /* ECDH or old-style key exchange? */
-
- 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 + 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(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");
+ /* SPTPS or old-style key exchange? */
+
+ if(from->status.sptps) {
+ char buf[strlen(key)];
+ int len = b64decode(key, buf, strlen(key));
+ if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
+ /* Uh-oh. It might be that the tunnel is stuck in some corrupted state,
+ so let's restart SPTPS in case that helps. But don't do that too often
+ to prevent storms.
+ Note that simply relying on handshake timeout is not enough, because
+ that doesn't apply to key regeneration. */
+ if(from->last_req_key < now.tv_sec - 10) {
+ logger(DEBUG_PROTOCOL, LOG_ERR, "Failed to decode handshake TCP packet from %s (%s), restarting SPTPS", from->name, from->hostname);
+ send_req_key(from);
+ }
return true;
}
- if(!from->ecdh) {
- if(!send_ans_key_ecdh(from))
- return true;
+ if(from->status.validkey) {
+ if(*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);
+ }
}
- char shared[ECDH_SHARED_SIZE * 2 + 1];
-
- if(!ecdh_compute_shared(&from->ecdh, key, shared))
- return true;
+ send_mtu_info(myself, from, MTU);
- /* Update our crypto end */
+ return true;
+ }
- size_t mykeylen = cipher_keylength(&myself->incipher);
- size_t hiskeylen = cipher_keylength(&from->outcipher);
+#ifdef DISABLE_LEGACY
+ logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses legacy protocol!", from->name, from->hostname);
+ return false;
+#else
+ /* Check and lookup cipher and digest algorithms */
- 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(cipher) {
+ if(!(from->outcipher = cipher_open_by_nid(cipher))) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
+ return false;
}
+ } else {
+ from->outcipher = NULL;
+ }
- 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);
+ if(digest) {
+ if(!(from->outdigest = digest_open_by_nid(digest, maclength))) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
+ return false;
+ }
+ } else {
+ from->outdigest = NULL;
+ }
- cipher_set_key(&from->outcipher, hiskey, true);
- digest_set_key(&from->outdigest, hiskey + hiskeylen, hiskeylen);
+ if(maclength != digest_length(from->outdigest)) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
+ return false;
+ }
- // Reset sequence number and late packet window
- mykeyused = true;
- from->received_seqno = 0;
- if(replaywin)
- memset(from->late, 0, replaywin);
+ /* Process key */
- if(strcmp(myself->name, from->name) < 0)
- memmove(key, key + mykeylen * 2, hiskeylen * 2);
- } else {
- keylen = hex2bin(key, key, sizeof key);
+ keylen = hex2bin(key, key, sizeof key);
- if(keylen != cipher_keylength(&from->outcipher)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
- return true;
- }
+ if(keylen != (from->outcipher ? cipher_keylength(from->outcipher) : 1)) {
+ 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 */
+ /* Update our copy of the origin's packet key */
- cipher_set_key(&from->outcipher, key, true);
- digest_set_key(&from->outdigest, key, keylen);
- }
+ if(from->outcipher && !cipher_set_key(from->outcipher, key, true))
+ return false;
+ if(from->outdigest && !digest_set_key(from->outdigest, key, keylen))
+ return false;
from->status.validkey = true;
from->sent_seqno = 0;
update_node_udp(from, &sa);
}
- if(from->options & OPTION_PMTU_DISCOVERY)
- send_mtu_probe(from);
-
return true;
+#endif
}
projects / tinc / blobdiff