X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fprotocol_auth.c;h=21a4b7e14055bdff220424e6bddbe18ff3e53d06;hb=bbeab00f46a6c856573fe0d2b9b85bce35728403;hp=d98e5c4b1a314f0324c80a786e01260fbe5058c2;hpb=86d83bd9bd69e2129f4e4e8397f1c7e223685e2f;p=tinc

diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index d98e5c4b..21a4b7e1 100644
--- a/src/protocol_auth.c
+++ b/src/protocol_auth.c
@@ -25,13 +25,16 @@
 #include "connection.h"
 #include "control.h"
 #include "control_common.h"
+#include "cipher.h"
 #include "crypto.h"
+#include "digest.h"
 #include "edge.h"
 #include "graph.h"
 #include "logger.h"
 #include "net.h"
 #include "netutl.h"
 #include "node.h"
+#include "prf.h"
 #include "protocol.h"
 #include "rsa.h"
 #include "utils.h"
@@ -40,8 +43,16 @@
 bool send_id(connection_t *c) {
 	gettimeofday(&c->start, NULL);
 
-	return send_request(c, "%d %s %d.%d", ID, myself->connection->name,
-						myself->connection->protocol_major, myself->connection->protocol_minor);
+	int minor = 0;
+
+	if(experimental) {
+		if(c->config_tree && !read_ecdsa_public_key(c))
+			minor = 1;
+		else
+			minor = myself->connection->protocol_minor;
+	}
+
+	return send_request(c, "%d %s %d.%d", ID, myself->connection->name, myself->connection->protocol_major, minor);
 }
 
 bool id_h(connection_t *c, char *request) {
@@ -107,22 +118,54 @@ bool id_h(connection_t *c, char *request) {
 				   c->name);
 			return false;
 		}
-	}
 
-	if(!read_rsa_public_key(c)) {
-		return false;
+		if(experimental && c->protocol_minor >= 2)
+			if(!read_ecdsa_public_key(c))
+				return false;
+	} else {
+		if(!ecdsa_active(&c->ecdsa))
+			c->protocol_minor = 1;
 	}
 
+	if(!experimental)
+		c->protocol_minor = 0;
+
 	c->allow_request = METAKEY;
 
-	return send_metakey(c);
+	if(c->protocol_minor >= 2)
+		return send_metakey_ec(c);
+	else
+		return send_metakey(c);
+}
+
+bool send_metakey_ec(connection_t *c) {
+	logger(LOG_DEBUG, "Sending ECDH metakey to %s", c->name);
+
+	size_t siglen = ecdsa_size(&myself->connection->ecdsa);
+
+	char key[ECDH_SIZE];
+	char sig[siglen];
+
+	// TODO: include nonce? Use relevant parts of SSH or TLS protocol
+
+	if(!ecdh_generate_public(&c->ecdh, key))
+		return false;
+
+	if(!ecdsa_sign(&myself->connection->ecdsa, key, ECDH_SIZE, sig))
+		return false;
+
+	char out[MAX_STRING_SIZE];
+
+	bin2hex(key, out, ECDH_SIZE);
+	bin2hex(sig, out + ECDH_SIZE * 2, siglen);
+	out[(ECDH_SIZE + siglen) * 2] = 0;
+	
+	bool result = send_request(c, "%d %s", METAKEY, out);
 }
 
 bool send_metakey(connection_t *c) {
-	size_t len = rsa_size(&c->rsa);
-	char key[len];
-	char enckey[len];
-	char hexkey[2 * len + 1];
+	if(!read_rsa_public_key(c))
+		return false;
 
 	if(!cipher_open_blowfish_ofb(&c->outcipher))
 		return false;
@@ -130,6 +173,11 @@ bool send_metakey(connection_t *c) {
 	if(!digest_open_sha1(&c->outdigest, -1))
 		return false;
 
+	size_t len = rsa_size(&c->rsa);
+	char key[len];
+	char enckey[len];
+	char hexkey[2 * len + 1];
+
 	/* Create a random key */
 
 	randomize(key, len);
@@ -182,7 +230,91 @@ bool send_metakey(connection_t *c) {
 	return result;
 }
 
+static bool metakey_ec_h(connection_t *c, const char *request) {
+	size_t siglen = ecdsa_size(&c->ecdsa);
+	char in[MAX_STRING_SIZE];
+	char key[MAX_STRING_SIZE];
+	char sig[siglen];
+
+	logger(LOG_DEBUG, "Got ECDH metakey from %s", c->name);
+
+	if(sscanf(request, "%*d " MAX_STRING, in) != 1) {
+		logger(LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
+		return false;
+	}
+
+	if(strlen(in) != (ECDH_SIZE + siglen) * 2) {
+		logger(LOG_ERR, "Possible intruder %s (%s): %s %d != %d", c->name, c->hostname, "wrong keylength", strlen(in) / 2, (ECDH_SIZE + siglen));
+		return false;
+	}
+
+	hex2bin(in, key, ECDH_SIZE);
+	hex2bin(in + ECDH_SIZE * 2, sig, siglen);
+
+	if(!ecdsa_verify(&c->ecdsa, key, ECDH_SIZE, sig)) {
+		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "invalid ECDSA signature");
+		return false;
+	}
+
+	char shared[ECDH_SHARED_SIZE * 2 + 1];
+
+	if(!ecdh_compute_shared(&c->ecdh, key, shared))
+		return false;
+
+	/* Update our crypto end */
+
+	if(!cipher_open_by_name(&c->incipher, "aes-256-ofb"))
+		return false;
+	if(!digest_open_by_name(&c->indigest, "sha512", -1))
+		return false;
+	if(!cipher_open_by_name(&c->outcipher, "aes-256-ofb"))
+		return false;
+	if(!digest_open_by_name(&c->outdigest, "sha512", -1))
+		return false;
+
+	size_t mykeylen = cipher_keylength(&c->incipher);
+	size_t hiskeylen = cipher_keylength(&c->outcipher);
+
+	char *mykey;
+	char *hiskey;
+	char *seed;
+	
+	if(strcmp(myself->name, c->name) < 0) {
+		mykey = key;
+		hiskey = key + mykeylen * 2;
+		xasprintf(&seed, "tinc TCP key expansion %s %s", myself->name, c->name);
+	} else {
+		mykey = key + hiskeylen * 2;
+		hiskey = key;
+		xasprintf(&seed, "tinc TCP key expansion %s %s", c->name, myself->name);
+	}
+
+	if(!prf(shared, ECDH_SHARED_SIZE, seed, strlen(seed), key, hiskeylen * 2 + mykeylen * 2))
+		return false;
+
+	free(seed);
+
+	bin2hex(shared, shared, ECDH_SHARED_SIZE);
+	shared[ECDH_SHARED_SIZE * 2] = 0;
+	logger(LOG_DEBUG, "Shared secret is %s", shared);
+
+	cipher_set_key(&c->incipher, mykey, true);
+	digest_set_key(&c->indigest, mykey + mykeylen, mykeylen);
+
+	cipher_set_key(&c->outcipher, hiskey, false);
+	digest_set_key(&c->outdigest, hiskey + hiskeylen, hiskeylen);
+
+	c->status.decryptin = true;
+	c->status.encryptout = true;
+	c->allow_request = CHALLENGE;
+
+	return send_challenge(c);
+}
+
 bool metakey_h(connection_t *c, char *request) {
+	if(c->protocol_minor >= 2)
+		return metakey_ec_h(c, request);
+
 	char hexkey[MAX_STRING_SIZE];
 	int cipher, digest, maclength, compression;
 	size_t len = rsa_size(&myself->connection->rsa);
@@ -238,7 +370,7 @@ bool metakey_h(connection_t *c, char *request) {
 }
 
 bool send_challenge(connection_t *c) {
-	size_t len = rsa_size(&c->rsa);
+	size_t len = c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&c->rsa);
 	char buffer[len * 2 + 1];
 
 	if(!c->hischallenge)
@@ -260,7 +392,7 @@ bool send_challenge(connection_t *c) {
 
 bool challenge_h(connection_t *c, char *request) {
 	char buffer[MAX_STRING_SIZE];
-	size_t len = rsa_size(&myself->connection->rsa);
+	size_t len = c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&myself->connection->rsa);
 	size_t digestlen = digest_length(&c->indigest);
 	char digest[digestlen];
 
@@ -318,7 +450,7 @@ bool chal_reply_h(connection_t *c, char *request) {
 
 	/* Verify the hash */
 
-	if(!digest_verify(&c->outdigest, c->hischallenge, rsa_size(&c->rsa), hishash)) {
+	if(!digest_verify(&c->outdigest, c->hischallenge, c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&c->rsa), hishash)) {
 		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
 		return false;
 	}
@@ -334,7 +466,24 @@ bool chal_reply_h(connection_t *c, char *request) {
 	return send_ack(c);
 }
 
+static bool send_upgrade(connection_t *c) {
+	/* Special case when protocol_minor is 1: the other end is ECDSA capable,
+	 * but doesn't know our key yet. So send it now. */
+
+	char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
+
+	if(!pubkey)
+		return false;
+
+	bool result = send_request(c, "%d %s", ACK, pubkey);
+	free(pubkey);
+	return result;
+}
+
 bool send_ack(connection_t *c) {
+	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. */
 
@@ -399,7 +548,29 @@ static void send_everything(connection_t *c) {
 	}
 }
 
+static bool upgrade_h(connection_t *c, char *request) {
+	char pubkey[MAX_STRING_SIZE];
+
+	if(sscanf(request, "%*d " MAX_STRING, pubkey) != 1) {
+		logger(LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name, c->hostname);
+		return false;
+	}
+
+	if(ecdsa_active(&c->ecdsa) || read_ecdsa_public_key(c)) {
+		logger(LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
+		return false;
+	}
+
+	logger(LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
+	append_connection_config(c, "ECDSAPublicKey", pubkey);
+	c->allow_request = TERMREQ;
+	return send_termreq(c);
+}
+
 bool ack_h(connection_t *c, char *request) {
+	if(c->protocol_minor == 1)
+		return upgrade_h(c, request);
+
 	char hisport[MAX_STRING_SIZE];
 	char *hisaddress;
 	int weight, mtu;