X-Git-Url: https://tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fprotocol_key.c;h=c392a469846e3878a53a65b84a110f43698df02e;hp=2453975d1fb345972bcfcb292d1c6bd771f80be5;hb=3fba80174dbe29bcfe0d121a2a1d2e61be5ee57b;hpb=6f9f6779e6bd1dd7bb795b42dad550863a386ca8

diff --git a/src/protocol_key.c b/src/protocol_key.c
index 2453975d..c392a469 100644
--- a/src/protocol_key.c
+++ b/src/protocol_key.c
@@ -1,7 +1,7 @@
 /*
     protocol_key.c -- handle the meta-protocol, key exchange
-    Copyright (C) 1999-2002 Ivo Timmermans <ivo@o2w.nl>,
-                  2000-2002 Guus Sliepen <guus@sliepen.eu.org>
+    Copyright (C) 1999-2005 Ivo Timmermans,
+                  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
@@ -13,249 +13,400 @@
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-
-    $Id: protocol_key.c,v 1.1.4.14 2002/09/09 22:33:03 guus Exp $
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
-#include "config.h"
-
-#include <stdlib.h>
-#include <string.h>
-#include <syslog.h>
-#include <stdio.h>
-#include <stdarg.h>
-#include <errno.h>
-
-#include <utils.h>
-#include <xalloc.h>
-#include <avl_tree.h>
+#include "system.h"
 
-#include "conf.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 "protocol.h"
-#include "meta.h"
-#include "connection.h"
 #include "node.h"
+#include "prf.h"
+#include "protocol.h"
+#include "utils.h"
+#include "xalloc.h"
 
-#include "system.h"
-
-int mykeyused = 0;
+static bool mykeyused = false;
 
-int send_key_changed(connection_t *c, node_t *n)
-{
-	cp();
+void send_key_changed(void) {
+	splay_node_t *node;
+	connection_t *c;
 
-	/* Only send this message if some other daemon requested our key previously.
-	   This reduces unnecessary key_changed broadcasts.
-	 */
+	send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name);
 
-	if(n == myself && !mykeyused)
-		return 0;
+	/* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
 
-	return send_request(c, "%d %lx %s", KEY_CHANGED, random(), n->name);
+	for(node = connection_tree->head; node; node = node->next) {
+		c = node->data;
+		if(c->status.active && c->node && c->node->status.reachable)
+			send_ans_key(c->node);
+	}
 }
 
-int key_changed_h(connection_t *c)
-{
+bool key_changed_h(connection_t *c, char *request) {
 	char name[MAX_STRING_SIZE];
 	node_t *n;
 
-	cp();
-
-	if(sscanf(c->buffer, "%*d %*x " MAX_STRING, name) != 1) {
-		syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "KEY_CHANGED",
+	if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
+		logger(LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
 			   c->name, c->hostname);
-		return -1;
+		return false;
 	}
 
-	if(seen_request(c->buffer))
-		return 0;
+	if(seen_request(request))
+		return true;
 
 	n = lookup_node(name);
 
 	if(!n) {
-		syslog(LOG_ERR, _("Got %s from %s (%s) origin %s which does not exist"),
+		logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
 			   "KEY_CHANGED", c->name, c->hostname, name);
-		return -1;
+		return true;
 	}
 
-	n->status.validkey = 0;
-	n->status.waitingforkey = 0;
+	n->status.validkey = false;
+	n->last_req_key = 0;
 
 	/* Tell the others */
 
-	forward_request(c);
+	if(!tunnelserver)
+		forward_request(c, request);
 
-	return 0;
+	return true;
 }
 
-int send_req_key(connection_t *c, node_t *from, node_t *to)
-{
-	cp();
-
-	return send_request(c, "%d %s %s", REQ_KEY, from->name, to->name);
+bool send_req_key(node_t *to) {
+	return send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, experimental ? 1 : 0);
 }
 
-int req_key_h(connection_t *c)
-{
+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;
 
-	cp();
-
-	if(sscanf(c->buffer, "%*d " MAX_STRING " " MAX_STRING, from_name, to_name) != 2) {
-		syslog(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, &kx_version) < 2) {
+		logger(LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
 			   c->hostname);
-		return -1;
+		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");
+		return false;
 	}
 
 	from = lookup_node(from_name);
 
 	if(!from) {
-		syslog(LOG_ERR, _("Got %s from %s (%s) origin %s which does not exist in our connection list"),
+		logger(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 -1;
+		return true;
 	}
 
 	to = lookup_node(to_name);
 
 	if(!to) {
-		syslog(LOG_ERR, _("Got %s from %s (%s) destination %s which does not exist in our connection list"),
+		logger(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 -1;
+		return true;
 	}
 
 	/* Check if this key request is for us */
 
 	if(to == myself) {			/* Yes, send our own key back */
-		mykeyused = 1;
-		from->received_seqno = 0;
-		send_ans_key(c, myself, from);
+		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 {
-		send_req_key(to->nexthop->connection, from, to);
+		if(tunnelserver)
+			return true;
+
+		if(!to->status.reachable) {
+			logger(LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
+				"REQ_KEY", c->name, c->hostname, to_name);
+			return true;
+		}
+
+		send_request(to->nexthop->connection, "%s", request);
 	}
 
-	return 0;
+	return true;
 }
 
-int send_ans_key(connection_t *c, node_t *from, node_t *to)
-{
-	char key[MAX_STRING_SIZE];
+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;
 
-	cp();
+	b64encode(key, key, ECDH_SIZE + siglen);
 
-	bin2hex(from->key, key, from->keylength);
-	key[from->keylength * 2] = '\0';
+	char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
 
-	return send_request(c, "%d %s %s %s %d %d %d %d", ANS_KEY,
-						from->name, to->name, key,
-						from->cipher ? from->cipher->nid : 0,
-						from->digest ? from->digest->type : 0, from->maclength,
-						from->compression);
+	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;
 }
 
-int ans_key_h(connection_t *c)
-{
+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];
+
+	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;
+	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,
+						cipher_get_nid(&to->incipher),
+						digest_get_nid(&to->indigest),
+						digest_length(&to->indigest),
+						to->incompression);
+}
+
+bool ans_key_h(connection_t *c, char *request) {
 	char from_name[MAX_STRING_SIZE];
 	char to_name[MAX_STRING_SIZE];
 	char key[MAX_STRING_SIZE];
-	int cipher, digest, maclength, compression;
+        char address[MAX_STRING_SIZE] = "";
+        char port[MAX_STRING_SIZE] = "";
+	int cipher, digest, maclength, compression, keylen;
 	node_t *from, *to;
 
-	cp();
-
-	if(sscanf(c->buffer, "%*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) != 7) {
-		syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ANS_KEY", c->name,
+		&compression, address, port) < 7) {
+		logger(LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
 			   c->hostname);
-		return -1;
+		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");
+		return false;
 	}
 
 	from = lookup_node(from_name);
 
 	if(!from) {
-		syslog(LOG_ERR, _("Got %s from %s (%s) origin %s which does not exist in our connection list"),
+		logger(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 -1;
+		return true;
 	}
 
 	to = lookup_node(to_name);
 
 	if(!to) {
-		syslog(LOG_ERR, _("Got %s from %s (%s) destination %s which does not exist in our connection list"),
+		logger(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 -1;
+		return true;
 	}
 
 	/* Forward it if necessary */
 
 	if(to != myself) {
-		return send_request(to->nexthop->connection, "%s", c->buffer);
+		if(tunnelserver)
+			return true;
+
+		if(!to->status.reachable) {
+			logger(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);
+			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);
 	}
 
-	/* Update our copy of the origin's packet key */
+	/* Check and lookup cipher and digest algorithms */
 
-	if(from->key)
-		free(from->key);
+	if(!cipher_open_by_nid(&from->outcipher, cipher)) {
+		logger(LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
+		return false;
+	}
 
-	from->key = xstrdup(key);
-	from->keylength = strlen(key) / 2;
-	hex2bin(from->key, from->key, from->keylength);
-	from->key[from->keylength] = '\0';
+	if(!digest_open_by_nid(&from->outdigest, digest, maclength)) {
+		logger(LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
+		return false;
+	}
 
-	from->status.validkey = 1;
-	from->status.waitingforkey = 0;
-	from->sent_seqno = 0;
+	if(maclength != digest_length(&from->outdigest)) {
+		logger(LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
+		return false;
+	}
 
-	/* Check and lookup cipher and digest algorithms */
+	if(compression < 0 || compression > 11) {
+		logger(LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
+		return true;
+	}
+
+	from->outcompression = compression;
+
+	/* 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(cipher) {
-		from->cipher = EVP_get_cipherbynid(cipher);
+		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(!from->cipher) {
-			syslog(LOG_ERR, _("Node %s (%s) uses unknown cipher!"), from->name,
-				   from->hostname);
-			return -1;
+			if(!ecdsa_set_base64_public_key(&from->ecdsa, pubkey))
+				return true;
+
+			append_config_file(from->name, "ECDSAPublicKey", pubkey);
 		}
 
-		if(from->keylength != from->cipher->key_len + from->cipher->iv_len) {
-			syslog(LOG_ERR, _("Node %s (%s) uses wrong keylength!"), from->name,
-				   from->hostname);
-			return -1;
+		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;
 		}
-	} else {
-		from->cipher = NULL;
-	}
 
-	from->maclength = maclength;
+		if(ECDH_SHARED_SIZE < cipher_keylength(&from->outcipher)) {
+			logger(LOG_ERR, "ECDH key too short for cipher of %s!", from->name);
+			return true;
+		}
 
-	if(digest) {
-		from->digest = EVP_get_digestbynid(digest);
+		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->digest) {
-			syslog(LOG_ERR, _("Node %s (%s) uses unknown digest!"), from->name,
-				   from->hostname);
-			return -1;
+		if(!from->ecdh) {
+			from->status.ecdh = true;
+			if(!send_ans_key(from))
+				return true;
 		}
 
-		if(from->maclength > from->digest->md_size || from->maclength < 0) {
-			syslog(LOG_ERR, _("Node %s (%s) uses bogus MAC length!"),
-				   from->name, from->hostname);
-			return -1;
+		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 {
-		from->digest = NULL;
+		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->compression = compression;
+	from->status.validkey = true;
+	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);
+		sockaddr_t sa = str2sockaddr(address, port);
+		update_node_udp(from, &sa);
+	}
 
-	flush_queue(from);
+	if(from->options & OPTION_PMTU_DISCOVERY)
+		send_mtu_probe(from);
 
-	return 0;
+	return true;
 }