X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fprotocol_auth.c;h=a542ca9ea922813b75cc741f24dbe8d1f2550c9c;hb=3fba80174dbe29bcfe0d121a2a1d2e61be5ee57b;hp=8d4dfb939eb881824e3cdd96e739f4c5190a4aca;hpb=79e46d08a46f2fef2ee4e8eac7ba487007160564;p=tinc

diff --git a/src/protocol_auth.c b/src/protocol_auth.c
index 8d4dfb93..a542ca9e 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"
@@ -40,14 +43,22 @@
 bool send_id(connection_t *c) {
 	gettimeofday(&c->start, NULL);
 
-	return send_request(c, "%d %s %d", ID, myself->connection->name,
-						myself->connection->protocol_version);
+	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) {
 	char name[MAX_STRING_SIZE];
 
-	if(sscanf(request, "%*d " MAX_STRING " %d", name, &c->protocol_version) != 2) {
+	if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
 		logger(LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
 			   c->hostname);
 		return false;
@@ -86,9 +97,9 @@ bool id_h(connection_t *c, char *request) {
 
 	/* Check if version matches */
 
-	if(c->protocol_version != myself->connection->protocol_version) {
-		logger(LOG_ERR, "Peer %s (%s) uses incompatible version %d",
-			   c->name, c->hostname, c->protocol_version);
+	if(c->protocol_major != myself->connection->protocol_major) {
+		logger(LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
+			   c->name, c->hostname, c->protocol_major, c->protocol_minor);
 		return false;
 	}
 
@@ -99,6 +110,9 @@ bool id_h(connection_t *c, char *request) {
 		return send_ack(c);
 	}
 
+	if(!experimental)
+		c->protocol_minor = 0;
+
 	if(!c->config_tree) {
 		init_configuration(&c->config_tree);
 
@@ -107,22 +121,46 @@ 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(c->protocol_minor && !ecdsa_active(&c->ecdsa))
+			c->protocol_minor = 1;
 	}
 
 	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 + siglen) * 2 + 1];
+
+	// 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, key + ECDH_SIZE))
+		return false;
+
+	b64encode(key, key, ECDH_SIZE + siglen);
+	
+	return send_request(c, "%d %s", METAKEY, key);
 }
 
 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 +168,11 @@ 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);
@@ -150,7 +193,6 @@ bool send_metakey(connection_t *c) {
 
 	ifdebug(SCARY_THINGS) {
 		bin2hex(key, hexkey, len);
-		hexkey[len * 2] = '\0';
 		logger(LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
 	}
 
@@ -169,7 +211,6 @@ bool send_metakey(connection_t *c) {
 	/* Convert the encrypted random data to a hexadecimal formatted string */
 
 	bin2hex(enckey, hexkey, len);
-	hexkey[len * 2] = '\0';
 
 	/* Send the meta key */
 
@@ -182,7 +223,84 @@ 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 key[MAX_STRING_SIZE];
+
+	logger(LOG_DEBUG, "Got ECDH metakey from %s", c->name);
+
+	if(sscanf(request, "%*d " MAX_STRING, key) != 1) {
+		logger(LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
+		return false;
+	}
+
+	int inlen = b64decode(key, key, sizeof key);
+
+	if(inlen != (ECDH_SIZE + siglen)) {
+		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
+		return false;
+	}
+
+	if(!ecdsa_verify(&c->ecdsa, key, ECDH_SIZE, key + ECDH_SIZE)) {
+		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "invalid ECDSA signature");
+		return false;
+	}
+
+	char shared[ECDH_SHARED_SIZE];
+
+	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);
+
+	cipher_set_key(&c->incipher, mykey, false);
+	digest_set_key(&c->indigest, mykey + mykeylen, mykeylen);
+
+	cipher_set_key(&c->outcipher, hiskey, true);
+	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);
@@ -194,17 +312,17 @@ bool metakey_h(connection_t *c, char *request) {
 		return false;
 	}
 
+	/* Convert the challenge from hexadecimal back to binary */
+
+	int inlen = hex2bin(hexkey, enckey, sizeof enckey);
+
 	/* Check if the length of the meta key is all right */
 
-	if(strlen(hexkey) != len * 2) {
+	if(inlen != len) {
 		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
 		return false;
 	}
 
-	/* Convert the challenge from hexadecimal back to binary */
-
-	hex2bin(hexkey, enckey, len);
-
 	/* Decrypt the meta key */
 
 	if(!rsa_private_decrypt(&myself->connection->rsa, enckey, len, key)) {
@@ -214,7 +332,6 @@ bool metakey_h(connection_t *c, char *request) {
 
 	ifdebug(SCARY_THINGS) {
 		bin2hex(key, hexkey, len);
-		hexkey[len * 2] = '\0';
 		logger(LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
 	}
 
@@ -238,7 +355,7 @@ 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)
@@ -251,7 +368,6 @@ bool send_challenge(connection_t *c) {
 	/* Convert to hex */
 
 	bin2hex(c->hischallenge, buffer, len);
-	buffer[len * 2] = '\0';
 
 	/* Send the challenge */
 
@@ -260,8 +376,8 @@ 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 digestlen = digest_length(&c->outdigest);
+	size_t len = c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&myself->connection->rsa);
+	size_t digestlen = digest_length(&c->indigest);
 	char digest[digestlen];
 
 	if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
@@ -269,17 +385,17 @@ bool challenge_h(connection_t *c, char *request) {
 		return false;
 	}
 
+	/* Convert the challenge from hexadecimal back to binary */
+
+	int inlen = hex2bin(buffer, buffer, sizeof buffer);
+
 	/* Check if the length of the challenge is all right */
 
-	if(strlen(buffer) != len * 2) {
+	if(inlen != len) {
 		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
 		return false;
 	}
 
-	/* Convert the challenge from hexadecimal back to binary */
-
-	hex2bin(buffer, buffer, len);
-
 	c->allow_request = CHAL_REPLY;
 
 	/* Calculate the hash from the challenge we received */
@@ -289,7 +405,6 @@ bool challenge_h(connection_t *c, char *request) {
 	/* Convert the hash to a hexadecimal formatted string */
 
 	bin2hex(digest, buffer, digestlen);
-	buffer[digestlen * 2] = '\0';
 
 	/* Send the reply */
 
@@ -305,20 +420,21 @@ bool chal_reply_h(connection_t *c, char *request) {
 		return false;
 	}
 
+	/* Convert the hash to binary format */
+
+	int inlen = hex2bin(hishash, hishash, sizeof hishash);
+
 	/* Check if the length of the hash is all right */
 
-	if(strlen(hishash) != digest_length(&c->outdigest) * 2) {
+	if(inlen != digest_length(&c->outdigest)) {
 		logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
 		return false;
 	}
 
-	/* Convert the hash to binary format */
-
-	hex2bin(hishash, hishash, digest_length(&c->outdigest));
 
 	/* 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 +450,24 @@ 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 +532,29 @@ 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_config_file(c->name, "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;
@@ -452,7 +607,7 @@ bool ack_h(connection_t *c, char *request) {
 	if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
 		n->mtu = mtu;
 
-	if(get_config_int(lookup_config(myself->connection->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
+	if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
 		n->mtu = mtu;
 
 	if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
@@ -462,6 +617,9 @@ bool ack_h(connection_t *c, char *request) {
 			c->options &= ~OPTION_CLAMP_MSS;
 	}
 
+	if(c->protocol_minor > 0)
+		c->node->status.ecdh = true;
+
 	/* Activate this connection */
 
 	c->allow_request = ALL;
@@ -493,7 +651,7 @@ bool ack_h(connection_t *c, char *request) {
 	if(tunnelserver)
 		send_add_edge(c, c->edge);
 	else
-		send_add_edge(broadcast, c->edge);
+		send_add_edge(everyone, c->edge);
 
 	/* Run MST and SSSP algorithms */