/*
protocol_key.c -- handle the meta-protocol, key exchange
- Copyright (C) 1999-2002 Ivo Timmermans <itimmermans@bigfoot.com>,
- 2000-2002 Guus Sliepen <guus@sliepen.warande.net>
+ 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
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 1.1.4.1 2002/02/11 10:05:58 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 "edge.h"
-\
-#include "system.h"
+#include "prf.h"
+#include "protocol.h"
+#include "utils.h"
+#include "xalloc.h"
+
+static bool mykeyused = false;
-int mykeyused = 0;
-
-int send_key_changed(connection_t *c, node_t *n)
-{
- connection_t *other;
- avl_node_t *node;
-cp
- /* Only send this message if some other daemon requested our key previously.
- This reduces unnecessary key_changed broadcasts.
- */
-
- if(n == myself && !mykeyused)
- return 0;
-
- for(node = connection_tree->head; node; node = node->next)
- {
- other = (connection_t *)node->data;
- if(other->status.active && other->status.mst && other != c)
- send_request(other, "%d %s", KEY_CHANGED, n->name);
- }
-cp
- return 0;
+void send_key_changed(void) {
+ splay_node_t *node;
+ connection_t *c;
+
+ send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name);
+
+ /* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
+
+ 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)
-{
- char name[MAX_STRING_SIZE];
- node_t *n;
-cp
- if(sscanf(c->buffer, "%*d "MAX_STRING, name) != 1)
- {
- syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "KEY_CHANGED",
- c->name, c->hostname);
- return -1;
- }
-
- n = lookup_node(name);
-
- if(!n)
- {
- syslog(LOG_ERR, _("Got %s from %s (%s) origin %s which does not exist"), "KEY_CHANGED",
- c->name, c->hostname, name);
- return -1;
- }
-
- n->status.validkey = 0;
- n->status.waitingforkey = 0;
- n->sent_seqno = 0;
-
- send_key_changed(c, n);
-cp
- return 0;
+bool key_changed_h(connection_t *c, char *request) {
+ char name[MAX_STRING_SIZE];
+ node_t *n;
+
+ 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 false;
+ }
+
+ if(seen_request(request))
+ return true;
+
+ n = lookup_node(name);
+
+ 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;
+
+ /* Tell the others */
+
+ if(!tunnelserver)
+ forward_request(c, request);
+
+ 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)
-{
- char from_name[MAX_STRING_SIZE];
- char to_name[MAX_STRING_SIZE];
- node_t *from, *to;
-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, c->hostname);
- return -1;
- }
-
- 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"), "REQ_KEY",
- c->name, c->hostname, from_name);
- return -1;
- }
-
- 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"), "REQ_KEY",
- c->name, c->hostname, to_name);
- return -1;
- }
-
- /* 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);
- }
- else
- {
-/* Proxy keys
- if(to->status.validkey)
- {
- send_ans_key(c, to, from);
- }
- else
-*/
- send_req_key(to->nexthop->connection, from, to);
- }
+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;
+
+ 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 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) {
+ 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 true;
+ }
+
+ to = lookup_node(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);
+ return true;
+ }
+
+ /* Check if this key request is for us */
+
+ if(to == myself) { /* Yes, send our own key back */
+ 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 {
+ 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 true;
+}
+
+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;
+
+ b64encode(key, key, ECDH_SIZE + siglen);
-cp
- return 0;
+ 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;
}
-int send_ans_key(connection_t *c, node_t *from, node_t *to)
-{
- char key[MAX_STRING_SIZE];
-cp
- bin2hex(from->key, key, from->keylength);
- key[from->keylength * 2] = '\0';
-cp
- return send_request(c, "%d %s %s %s %d %d %d", ANS_KEY,
- from->name, to->name, key, from->cipher?from->cipher->nid:0, from->digest?from->digest->type:0, from->maclength);
+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);
}
-int ans_key_h(connection_t *c)
-{
- char from_name[MAX_STRING_SIZE];
- char to_name[MAX_STRING_SIZE];
- char key[MAX_STRING_SIZE];
- int cipher, digest, maclength;
- node_t *from, *to;
-cp
- if(sscanf(c->buffer, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d", from_name, to_name, key, &cipher, &digest, &maclength) != 6)
- {
- syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ANS_KEY",
- c->name, c->hostname);
- return -1;
- }
-
- 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"), "ANS_KEY",
- c->name, c->hostname, from_name);
- return -1;
- }
-
- 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"), "ANS_KEY",
- c->name, c->hostname, to_name);
- return -1;
- }
-
- /* Forward it if necessary */
-
- if(to != myself)
- {
- return send_request(to->nexthop->connection, c->buffer);
- }
-
- /* Update our copy of the origin's packet key */
-
- if(from->key)
- free(from->key);
-
- from->key = xstrdup(key);
- from->keylength = strlen(key) / 2;
- hex2bin(from->key, from->key, from->keylength);
- from->key[from->keylength] = '\0';
-
- from->status.validkey = 1;
- from->status.waitingforkey = 0;
-
- /* Check and lookup cipher and digest algorithms */
-
- if(cipher)
- {
- from->cipher = EVP_get_cipherbynid(cipher);
- if(!from->cipher)
- {
- syslog(LOG_ERR, _("Node %s (%s) uses unknown cipher!"), from->name, from->hostname);
- return -1;
+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];
+ char address[MAX_STRING_SIZE] = "";
+ char port[MAX_STRING_SIZE] = "";
+ 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,
+ 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);
+ 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) {
+ 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 true;
}
- 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;
- }
- }
- else
- {
- from->cipher = NULL;
- }
-
- if(digest)
- {
- from->digest = EVP_get_digestbynid(digest);
- if(!from->digest)
- {
- syslog(LOG_ERR, _("Node %s (%s) uses unknown digest!"), from->name, from->hostname);
- return -1;
+
+ to = lookup_node(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);
+ return true;
+ }
+
+ /* Forward it if necessary */
+
+ if(to != myself) {
+ 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);
+ }
+
+ /* Check and lookup cipher and digest algorithms */
+
+ if(!cipher_open_by_nid(&from->outcipher, cipher)) {
+ logger(LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
+ return false;
}
- from->maclength = maclength;
- 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;
+
+ if(!digest_open_by_nid(&from->outdigest, digest, maclength)) {
+ logger(LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
+ return false;
+ }
+
+ if(maclength != digest_length(&from->outdigest)) {
+ logger(LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
+ return false;
}
- }
- else
- {
- from->digest = NULL;
- from->maclength = maclength;
- }
-
- flush_queue(from);
-cp
- return 0;
+
+ 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(!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);
+ }
+
+ 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 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 true;
+ }
+
+ 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 {
+ 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->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);
+ }
+
+ if(from->options & OPTION_PMTU_DISCOVERY)
+ send_mtu_probe(from);
+
+ return true;
}
projects / tinc / blobdiff