X-Git-Url: http://git.meshlink.io/?p=meshlink;a=blobdiff_plain;f=src%2Fprotocol_key.c;h=b614494b74b55cc2b41fdc0daaffa7f1ef00ff9a;hp=e2e4be5db8ec8e90b0e61006c19d4d6a28c8b872;hb=963c5055505f2fc117cd5efa06eaa02c9b2bf85d;hpb=f99661a4ca5bacff47239ce7978b9c9948917c54

diff --git a/src/protocol_key.c b/src/protocol_key.c
index e2e4be5d..b614494b 100644
--- a/src/protocol_key.c
+++ b/src/protocol_key.c
@@ -1,7 +1,6 @@
 /*
     protocol_key.c -- handle the meta-protocol, key exchange
-    Copyright (C) 1999-2005 Ivo Timmermans,
-                  2000-2010 Guus Sliepen <guus@tinc-vpn.org>
+    Copyright (C) 2014-2017 Guus Sliepen <guus@meshlink.io>
 
     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
@@ -20,164 +19,268 @@
 
 #include "system.h"
 
-#include <openssl/evp.h>
-#include <openssl/err.h>
-#include <openssl/rand.h>
-
-#include "avl_tree.h"
 #include "connection.h"
 #include "logger.h"
+#include "meshlink_internal.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"
 
-bool mykeyused = false;
+static const int req_key_timeout = 2;
 
-void send_key_changed() {
-	avl_node_t *node;
-	connection_t *c;
+bool key_changed_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
+	assert(request);
+	assert(*request);
 
-	send_request(broadcast, "%d %x %s", KEY_CHANGED, rand(), myself->name);
+	char name[MAX_STRING_SIZE];
+	node_t *n;
 
-	/* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
+	if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
+		logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "KEY_CHANGED", c->name);
+		return false;
+	}
 
-	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);
+	if(seen_request(mesh, request)) {
+		return true;
 	}
+
+	n = lookup_node(mesh, name);
+
+	if(!n) {
+		logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist", "KEY_CHANGED", c->name, name);
+		return true;
+	}
+
+	/* Tell the others */
+
+	forward_request(mesh, c, NULL, request);
+
+	return true;
 }
 
-bool key_changed_h(connection_t *c) {
-	char name[MAX_STRING_SIZE];
-	node_t *n;
+static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
+	(void)type;
 
-	if(sscanf(c->buffer, "%*d %*x " MAX_STRING, name) != 1) {
-		logger(LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
-			   c->name, c->hostname);
-		return false;
+	assert(data);
+	assert(len);
+
+	node_t *to = handle;
+	meshlink_handle_t *mesh = to->mesh;
+	to->sptps.send_data = send_sptps_data;
+	char buf[len * 4 / 3 + 5];
+	b64encode(data, buf, len);
+	return send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, to->name, REQ_KEY, buf);
+}
+
+bool send_req_key(meshlink_handle_t *mesh, node_t *to) {
+	if(!node_read_public_key(mesh, to)) {
+		logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", to->name);
+		send_request(mesh, to->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, to->name, REQ_PUBKEY);
+		return true;
 	}
 
-	if(!check_id(name)) {
-		logger(LOG_ERR, "Got bad %s from %s (%s): %s", "KEY_CHANGED", c->name, c->hostname, "invalid name");
-		return false;
+	if(to->sptps.label) {
+		logger(mesh, MESHLINK_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
 	}
 
-	if(seen_request(c->buffer))
+	char label[sizeof(meshlink_udp_label) + strlen(mesh->self->name) + strlen(to->name) + 2];
+	snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, mesh->self->name, to->name);
+	sptps_stop(&to->sptps);
+	to->status.validkey = false;
+	to->status.waitingforkey = true;
+	to->last_req_key = mesh->loop.now.tv_sec;
+	return sptps_start(&to->sptps, to, true, true, mesh->private_key, to->ecdsa, label, sizeof(label) - 1, send_initial_sptps_data, receive_sptps_record);
+}
+
+/* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
+
+static bool req_key_ext_h(meshlink_handle_t *mesh, connection_t *c, const char *request, node_t *from, int reqno) {
+	(void)c;
+
+	switch(reqno) {
+	case REQ_PUBKEY: {
+		char *pubkey = ecdsa_get_base64_public_key(mesh->private_key);
+
+		if(!from->nexthop || !from->nexthop->connection) {
+			return false;
+		}
+
+		send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d %s", REQ_KEY, mesh->self->name, from->name, ANS_PUBKEY, pubkey);
+		free(pubkey);
 		return true;
+	}
 
-	n = lookup_node(name);
+	case ANS_PUBKEY: {
+		if(node_read_public_key(mesh, from)) {
+			logger(mesh, MESHLINK_WARNING, "Got ANS_PUBKEY from %s even though we already have his pubkey", from->name);
+			return true;
+		}
+
+		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(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_PUBKEY", from->name, "invalid pubkey");
+			return true;
+		}
+
+		logger(mesh, MESHLINK_INFO, "Learned ECDSA public key from %s", from->name);
+		from->status.dirty = true;
+
+		/* If we are trying to form an outgoing connection to this node, retry immediately */
+		for list_each(outgoing_t, outgoing, mesh->outgoings) {
+			if(outgoing->node == from && outgoing->ev.cb) {
+				outgoing->timeout = 0;
+				timeout_set(&mesh->loop, &outgoing->ev, &(struct timespec) {
+					0, 0
+				});
+			}
+		}
+
+		/* Also reset any UTCP timers */
+		utcp_reset_timers(from->utcp);
 
-	if(!n) {
-		logger(LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
-			   "KEY_CHANGED", c->name, c->hostname, name);
 		return true;
 	}
 
-	n->status.validkey = false;
-	n->last_req_key = 0;
+	case REQ_KEY: {
+		if(!node_read_public_key(mesh, from)) {
+			logger(mesh, MESHLINK_DEBUG, "No ECDSA key known for %s", from->name);
+			send_request(mesh, from->nexthop->connection, NULL, "%d %s %s %d", REQ_KEY, mesh->self->name, from->name, REQ_PUBKEY);
+			return true;
+		}
+
+		if(from->sptps.label) {
+			logger(mesh, MESHLINK_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
 
-	/* Tell the others */
+			if(mesh->loop.now.tv_sec < from->last_req_key + req_key_timeout && strcmp(mesh->self->name, from->name) < 0) {
+				logger(mesh, MESHLINK_DEBUG, "Ignoring REQ_KEY from %s.", from->name);
+				return true;
+			}
+		}
 
-	if(!tunnelserver)
-		forward_request(c);
+		char buf[MAX_STRING_SIZE];
+		int len;
 
-	return true;
-}
+		if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
+			logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS_START", from->name, "invalid SPTPS data");
+			return true;
+		}
+
+		char label[sizeof(meshlink_udp_label) + strlen(from->name) + strlen(mesh->self->name) + 2];
+		snprintf(label, sizeof(label), "%s %s %s", meshlink_udp_label, from->name, mesh->self->name);
+		sptps_stop(&from->sptps);
+		from->status.validkey = false;
+		from->status.waitingforkey = true;
+		from->last_req_key = mesh->loop.now.tv_sec;
 
-bool send_req_key(node_t *to) {
-	return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
+		if(!sptps_start(&from->sptps, from, false, true, mesh->private_key, from->ecdsa, label, sizeof(label) - 1, send_sptps_data, receive_sptps_record)) {
+			logger(mesh, MESHLINK_ERROR, "Could not start SPTPS session with %s: %s", from->name, strerror(errno));
+			return true;
+		}
+
+		if(!sptps_receive_data(&from->sptps, buf, len)) {
+			logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
+			return true;
+		}
+
+		return true;
+	}
+
+	case REQ_SPTPS: {
+		if(!from->status.validkey) {
+			logger(mesh, MESHLINK_ERROR, "Got REQ_SPTPS from %s but we don't have a valid key yet", from->name);
+			return true;
+		}
+
+		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(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_SPTPS", from->name, "invalid SPTPS data");
+			return true;
+		}
+
+		if(!sptps_receive_data(&from->sptps, buf, len)) {
+			logger(mesh, MESHLINK_ERROR, "Could not process SPTPS data from %s: %s", from->name, strerror(errno));
+			return true;
+		}
+
+		return true;
+	}
+
+	default:
+		logger(mesh, MESHLINK_ERROR, "Unknown extended REQ_KEY request from %s: %s", from->name, request);
+		return true;
+	}
 }
 
-bool req_key_h(connection_t *c) {
+bool req_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
+	assert(request);
+	assert(*request);
+
 	char from_name[MAX_STRING_SIZE];
 	char to_name[MAX_STRING_SIZE];
 	node_t *from, *to;
+	int reqno = 0;
 
-	if(sscanf(c->buffer, "%*d " MAX_STRING " " MAX_STRING, from_name, to_name) != 2) {
-		logger(LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
-			   c->hostname);
+	if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
+		logger(mesh, MESHLINK_ERROR, "Got bad %s from %s", "REQ_KEY", c->name);
 		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");
+		logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "REQ_KEY", c->name, "invalid name");
 		return false;
 	}
 
-	from = lookup_node(from_name);
+	from = lookup_node(mesh, from_name);
 
 	if(!from) {
-		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);
+		logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
+		       "REQ_KEY", c->name, from_name);
 		return true;
 	}
 
-	to = lookup_node(to_name);
+	to = lookup_node(mesh, to_name);
 
 	if(!to) {
-		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);
+		logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
+		       "REQ_KEY", c->name, to_name);
 		return true;
 	}
 
 	/* Check if this key request is for us */
 
-	if(to == myself) {			/* Yes, send our own key back */
-		send_ans_key(from);
-	} else {
-		if(tunnelserver)
-			return true;
+	if(to == mesh->self) {                      /* Yes */
+		/* Is this an extended REQ_KEY message? */
+		if(reqno) {
+			return req_key_ext_h(mesh, c, request, from, reqno);
+		}
 
+		/* This should never happen. Ignore it, unless it came directly from the connected peer, in which case we disconnect. */
+		return from->connection != c;
+	} else {
 		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);
+			logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
+			       "REQ_KEY", c->name, to_name);
 			return true;
 		}
 
-		send_request(to->nexthop->connection, "%s", c->buffer);
+		send_request(mesh, to->nexthop->connection, NULL, "%s", request);
 	}
 
 	return true;
 }
 
-bool send_ans_key(node_t *to) {
-	// Set key parameters
-	to->incipher = myself->incipher;
-	to->inkeylength = myself->inkeylength;
-	to->indigest = myself->indigest;
-	to->inmaclength = myself->inmaclength;
-	to->incompression = myself->incompression;
-
-	// Allocate memory for key
-	to->inkey = xrealloc(to->inkey, to->inkeylength);
-
-	// Create a new key
-	RAND_pseudo_bytes((unsigned char *)to->inkey, to->inkeylength);
-	if(to->incipher)
-		EVP_DecryptInit_ex(&to->inctx, to->incipher, NULL, (unsigned char *)to->inkey, (unsigned char *)to->inkey + to->incipher->key_len);
-
-	// Reset sequence number and late packet window
-	mykeyused = true;
-	to->received_seqno = 0;
-	if(replaywin) memset(to->late, 0, replaywin);
-
-	// Convert to hexadecimal and send
-	char key[2 * to->inkeylength + 1];
-	bin2hex(to->inkey, key, to->inkeylength);
-	key[to->inkeylength * 2] = '\0';
-
-	return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
-			myself->name, to->name, key,
-			to->incipher ? to->incipher->nid : 0,
-			to->indigest ? to->indigest->type : 0, to->inmaclength,
-			to->incompression);
-}
+bool ans_key_h(meshlink_handle_t *mesh, connection_t *c, const char *request) {
+	assert(request);
+	assert(*request);
 
-bool ans_key_h(connection_t *c) {
 	char from_name[MAX_STRING_SIZE];
 	char to_name[MAX_STRING_SIZE];
 	char key[MAX_STRING_SIZE];
@@ -186,132 +289,123 @@ bool ans_key_h(connection_t *c) {
 	int cipher, digest, maclength, compression;
 	node_t *from, *to;
 
-	if(sscanf(c->buffer, "%*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,
-			   c->hostname);
+	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(mesh, MESHLINK_ERROR, "Got bad %s from %s", "ANS_KEY", c->name);
 		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");
+		logger(mesh, MESHLINK_ERROR, "Got bad %s from %s: %s", "ANS_KEY", c->name, "invalid name");
 		return false;
 	}
 
-	from = lookup_node(from_name);
+	from = lookup_node(mesh, from_name);
 
 	if(!from) {
-		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);
+		logger(mesh, MESHLINK_ERROR, "Got %s from %s origin %s which does not exist in our connection list",
+		       "ANS_KEY", c->name, from_name);
 		return true;
 	}
 
-	to = lookup_node(to_name);
+	to = lookup_node(mesh, to_name);
 
 	if(!to) {
-		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);
+		logger(mesh, MESHLINK_ERROR, "Got %s from %s destination %s which does not exist in our connection list",
+		       "ANS_KEY", c->name, to_name);
 		return true;
 	}
 
 	/* Forward it if necessary */
 
-	if(to != myself) {
-		if(tunnelserver)
+	if(to != mesh->self) {
+		if(!to->status.reachable) {
+			logger(mesh, MESHLINK_WARNING, "Got %s from %s destination %s which is not reachable",
+			       "ANS_KEY", c->name, to_name);
 			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);
+		if(from == to) {
+			logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
+			       "ANS_KEY", c->name, from_name, to_name);
 			return true;
 		}
 
-		if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
+		/* Append the known UDP address of the from node, if we have a confirmed one */
+		if(!*address && from->status.udp_confirmed && 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);
+			logger(mesh, MESHLINK_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", c->buffer, address, port);
+			send_request(mesh, to->nexthop->connection, NULL, "%s %s %s", request, address, port);
 			free(address);
 			free(port);
 			return true;
 		}
 
-		return send_request(to->nexthop->connection, "%s", c->buffer);
+		return send_request(mesh, to->nexthop->connection, NULL, "%s", request);
 	}
 
-	/* Update our copy of the origin's packet key */
-	from->outkey = xrealloc(from->outkey, strlen(key) / 2);
+	/* Is this an ANS_KEY informing us of our own reflexive UDP address? */
 
-	from->outkey = xstrdup(key);
-	from->outkeylength = strlen(key) / 2;
-	hex2bin(key, from->outkey, from->outkeylength);
+	if(from == mesh->self) {
+		if(*key == '.' && *address && *port) {
+			logger(mesh, MESHLINK_DEBUG, "Learned our own reflexive UDP address from %s: %s port %s", c->name, address, port);
 
-	/* Check and lookup cipher and digest algorithms */
+			/* Inform all other nodes we want to communicate with and which are reachable via this connection */
+			for splay_each(node_t, n, mesh->nodes) {
+				if(n->nexthop != c->node) {
+					continue;
+				}
 
-	if(cipher) {
-		from->outcipher = EVP_get_cipherbynid(cipher);
+				if(n->status.udp_confirmed) {
+					continue;
+				}
 
-		if(!from->outcipher) {
-			logger(LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name,
-				   from->hostname);
-			return true;
-		}
+				if(!n->status.waitingforkey && !n->status.validkey) {
+					continue;
+				}
 
-		if(from->outkeylength != from->outcipher->key_len + from->outcipher->iv_len) {
-			logger(LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name,
-				   from->hostname);
-			return true;
+				logger(mesh, MESHLINK_DEBUG, "Forwarding our own reflexive UDP address to %s", n->name);
+				send_request(mesh, c, NULL, "%d %s %s . -1 -1 -1 0 %s %s", ANS_KEY, mesh->self->name, n->name, address, port);
+			}
+		} else {
+			logger(mesh, MESHLINK_WARNING, "Got %s from %s from %s to %s",
+			       "ANS_KEY", c->name, from_name, to_name);
 		}
-	} else {
-		from->outcipher = NULL;
+
+		return true;
 	}
 
-	from->outmaclength = maclength;
+	/* Process SPTPS data if present */
 
-	if(digest) {
-		from->outdigest = EVP_get_digestbynid(digest);
+	if(*key != '.') {
+		/* Don't use key material until every check has passed. */
+		from->status.validkey = false;
 
-		if(!from->outdigest) {
-			logger(LOG_ERR, "Node %s (%s) uses unknown digest!", from->name,
-				   from->hostname);
+		/* Compression is not supported. */
+		if(compression != 0) {
+			logger(mesh, MESHLINK_ERROR, "Node %s uses bogus compression level!", from->name);
 			return true;
 		}
 
-		if(from->outmaclength > from->outdigest->md_size || from->outmaclength < 0) {
-			logger(LOG_ERR, "Node %s (%s) uses bogus MAC length!",
-				   from->name, from->hostname);
-			return true;
-		}
-	} else {
-		from->outdigest = NULL;
-	}
+		char buf[strlen(key)];
+		int len = b64decode(key, buf, strlen(key));
 
-	if(compression < 0 || compression > 11) {
-		logger(LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
-		return true;
+		if(!len || !sptps_receive_data(&from->sptps, buf, len)) {
+			logger(mesh, MESHLINK_ERROR, "Error processing SPTPS data from %s", from->name);
+		}
 	}
-	
-	from->outcompression = compression;
 
-	if(from->outcipher)
-		if(!EVP_EncryptInit_ex(&from->outctx, from->outcipher, NULL, (unsigned char *)from->outkey, (unsigned char *)from->outkey + from->outcipher->key_len)) {
-			logger(LOG_ERR, "Error during initialisation of key from %s (%s): %s",
-					from->name, from->hostname, ERR_error_string(ERR_get_error(), NULL));
-			return true;
+	if(from->status.validkey) {
+		if(*address && *port) {
+			logger(mesh, MESHLINK_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
+			sockaddr_t sa = str2sockaddr(address, port);
+			update_node_udp(mesh, from, &sa);
 		}
 
-	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);
+		send_mtu_probe(mesh, from);
 	}
 
-	if(from->options & OPTION_PMTU_DISCOVERY && !from->mtuevent)
-		send_mtu_probe(from);
-
 	return true;
 }