X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fprotocol_key.c;h=c392a469846e3878a53a65b84a110f43698df02e;hb=3fba80174dbe29bcfe0d121a2a1d2e61be5ee57b;hp=029b41a4da848593b0687be23cdba68c7e8b048e;hpb=8b2b67e26c5b971761f5015764d5e188f6343bc4;p=meshlink diff --git a/src/protocol_key.c b/src/protocol_key.c index 029b41a4..c392a469 100644 --- a/src/protocol_key.c +++ b/src/protocol_key.c @@ -1,7 +1,7 @@ /* protocol_key.c -- handle the meta-protocol, key exchange - Copyright (C) 1999-2002 Ivo Timmermans , - 2000-2002 Guus Sliepen + Copyright (C) 1999-2005 Ivo Timmermans, + 2000-2011 Guus Sliepen 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 @@ -13,257 +13,400 @@ 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 1.1.4.10 2002/09/04 16:26:45 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 -#include -#include -#include -#include -#include - -#include -#include -#include +#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 "prf.h" +#include "protocol.h" +#include "utils.h" +#include "xalloc.h" -#include "system.h" +static bool mykeyused = false; + +void send_key_changed(void) { + splay_node_t *node; + connection_t *c; -int mykeyused = 0; + send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name); -int send_key_changed(connection_t *c, node_t *n) -{ -cp - /* Only send this message if some other daemon requested our key previously. - This reduces unnecessary key_changed broadcasts. - */ + /* Immediately send new keys to directly connected nodes to keep UDP mappings alive */ - if(n == myself && !mykeyused) - return 0; -cp - return send_request(c, "%d %lx %s", KEY_CHANGED, random(), n->name); + 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 %*x "MAX_STRING, name) != 1) - { - syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "KEY_CHANGED", - c->name, c->hostname); - return -1; - } - - if(seen_request(c->buffer)) - return 0; - - 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; - - /* Tell the others */ - - forward_request(c); -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->sent_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); -cp - return 0; + 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; } -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 %d", ANS_KEY, - from->name, to->name, key, from->cipher?from->cipher->nid:0, from->digest?from->digest->type:0, from->maclength, from->compression); +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); + + 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) { + 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, compression; - node_t *from, *to; -cp - if(sscanf(c->buffer, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d", from_name, to_name, key, &cipher, &digest, &maclength, &compression) != 7) - { - 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, "%s", 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; - from->received_seqno = 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; + } + + 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; + } + + 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(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; - } - - from->maclength = maclength; - - 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; + + if(maclength != digest_length(&from->outdigest)) { + logger(LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname); + return false; } - 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(compression < 0 || compression > 11) { + logger(LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname); + return true; } - } - else - { - from->digest = NULL; - } - - from->compression = compression; - - flush_queue(from); -cp - return 0; + + 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; }