X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fprotocol_key.c;h=5246e7d2d8cc573c808600fdff934604154ef5ee;hb=cff27a258f3b3a97b5d2e309c264eceea41dff3a;hp=0ae95681bcbdc604de838beb1fe486dc81b67b00;hpb=bbeab00f46a6c856573fe0d2b9b85bce35728403;p=meshlink

diff --git a/src/protocol_key.c b/src/protocol_key.c
index 0ae95681..5246e7d2 100644
--- a/src/protocol_key.c
+++ b/src/protocol_key.c
@@ -145,19 +145,31 @@ bool req_key_h(connection_t *c, char *request) {
 }
 
 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;
 
-	bin2hex(key, key, ECDH_SIZE);
-	key[ECDH_SIZE * 2] = '\0';
+	if(!ecdsa_sign(&myself->connection->ecdsa, key, ECDH_SIZE, key + ECDH_SIZE))
+		return false;
 
-	return send_request(to->nexthop->connection, "%d %s %s ECDH:%s %d %d %zu %d", ANS_KEY,
-						myself->name, to->name, key,
+	b64encode(key, key, ECDH_SIZE + siglen);
+
+	char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
+
+	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;
 }
 
 bool send_ans_key(node_t *to) {
@@ -172,11 +184,10 @@ bool send_ans_key(node_t *to) {
 	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;
@@ -200,7 +211,7 @@ bool ans_key_h(connection_t *c, char *request) {
 	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,
@@ -281,30 +292,53 @@ bool ans_key_h(connection_t *c, char *request) {
 	/* ECDH or old-style key exchange? */
 	
 	if(experimental && !strncmp(key, "ECDH:", 5)) {
-		keylen = (strlen(key) - 5) / 2;
+		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(!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(!ecdsa_set_base64_public_key(&from->ecdsa, pubkey))
+				return true;
+
+			append_config_file(from->name, "ECDSAPublicKey", pubkey);
+		}
 
-		if(keylen != ECDH_SIZE) {
-			logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
-			return false;
+		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;
 		}
 
 		if(ECDH_SHARED_SIZE < cipher_keylength(&from->outcipher)) {
 			logger(LOG_ERR, "ECDH key too short for cipher of %s!", from->name);
-			return false;
+			return true;
+		}
+
+		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->ecdh) {
 			from->status.ecdh = true;
 			if(!send_ans_key(from))
-				return false;
+				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;
+			return true;
 
 		/* Update our crypto end */
 
@@ -326,7 +360,7 @@ bool ans_key_h(connection_t *c, char *request) {
 		}
 
 		if(!prf(shared, ECDH_SHARED_SIZE, seed, strlen(seed), key, hiskeylen * 2 + mykeylen * 2))
-			return false;
+			return true;
 
 		free(seed);
 
@@ -334,10 +368,10 @@ bool ans_key_h(connection_t *c, char *request) {
 		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
@@ -349,17 +383,16 @@ bool ans_key_h(connection_t *c, char *request) {
 		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;
+			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);
 	}