X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fprotocol_key.c;h=a18cefc917b50a706f23e48d54c5bc61cb6cbf20;hp=22692bb614e97632d2224bedbd77b1fb28647976;hb=af81c436d6e11a53803747af7cc8ecfd449ccd4c;hpb=4b6a9f1c1f645ce5989692655337d9e23ca28648 diff --git a/src/protocol_key.c b/src/protocol_key.c index 22692bb6..a18cefc9 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) 1999-2005 Ivo Timmermans, - 2000-2010 Guus Sliepen + 2000-2017 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 @@ -20,98 +20,243 @@ #include "system.h" -#include -#include -#include - -#include "avl_tree.h" +#include "cipher.h" #include "connection.h" +#include "crypto.h" #include "logger.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; - -void send_key_changed() { - avl_node_t *node; - connection_t *c; +static bool mykeyused = false; - send_request(broadcast, "%d %x %s", KEY_CHANGED, rand(), myself->name); +void send_key_changed(void) { +#ifndef DISABLE_LEGACY + 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) + for list_each(connection_t, c, connection_list) + if(c->edge && c->node && c->node->status.reachable && !c->node->status.sptps) send_ans_key(c->node); +#endif + + /* Force key exchange for connections using SPTPS */ + + if(experimental) { + for splay_each(node_t, n, node_tree) + if(n->status.reachable && n->status.validkey && n->status.sptps) + sptps_force_kex(&n->sptps); } } -bool key_changed_h(connection_t *c) { +bool key_changed_h(connection_t *c, const char *request) { char name[MAX_STRING_SIZE]; node_t *n; - if(sscanf(c->buffer, "%*d %*x " MAX_STRING, name) != 1) { - logger(LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED", + if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) { + logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED", c->name, c->hostname); return false; } - 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(seen_request(c->buffer)) + 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", + logger(DEBUG_ALWAYS, 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; + if(!n->status.sptps) { + n->status.validkey = false; + n->last_req_key = 0; + } /* Tell the others */ if(!tunnelserver) - forward_request(c); + forward_request(c, request); return true; } +static bool send_sptps_data_myself(void *handle, uint8_t type, const void *data, size_t len) { + return send_sptps_data(handle, myself, type, data, len); +} + +static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) { + node_t *to = handle; + to->sptps.send_data = send_sptps_data_myself; + char buf[len * 4 / 3 + 5]; + b64encode(data, buf, len); + return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_KEY, buf); +} + bool send_req_key(node_t *to) { + if(to->status.sptps) { + if(!node_read_ecdsa_public_key(to)) { + logger(DEBUG_PROTOCOL, LOG_DEBUG, "No Ed25519 key known for %s (%s)", to->name, to->hostname); + send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, REQ_PUBKEY); + return true; + } + + char label[25 + strlen(myself->name) + strlen(to->name)]; + snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name); + sptps_stop(&to->sptps); + to->status.validkey = false; + to->status.waitingforkey = true; + to->last_req_key = now.tv_sec; + to->incompression = myself->incompression; + return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof label, send_initial_sptps_data, receive_sptps_record); + } + return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name); } -bool req_key_h(connection_t *c) { +/* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */ + +static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, node_t *to, int reqno) { + /* If this is a SPTPS packet, see if sending UDP info helps. + Note that we only do this if we're the destination or the static relay; + otherwise every hop would initiate its own UDP info message, resulting in elevated chatter. */ + if((reqno == REQ_KEY || reqno == SPTPS_PACKET) && to->via == myself) + send_udp_info(myself, from); + + if(reqno == SPTPS_PACKET) { + /* This is a SPTPS data packet. */ + + 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(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s) to %s (%s): %s", "SPTPS_PACKET", from->name, from->hostname, to->name, to->hostname, "invalid SPTPS data"); + return true; + } + + if(to != myself) { + /* We don't just forward the request, because we want to use UDP if it's available. */ + send_sptps_data(to, from, 0, buf, len); + try_tx(to, true); + } else { + /* The packet is for us */ + if(!sptps_receive_data(&from->sptps, buf, len)) { + /* Uh-oh. It might be that the tunnel is stuck in some corrupted state, + so let's restart SPTPS in case that helps. But don't do that too often + to prevent storms. */ + if(from->last_req_key < now.tv_sec - 10) { + logger(DEBUG_PROTOCOL, LOG_ERR, "Failed to decode TCP packet from %s (%s), restarting SPTPS", from->name, from->hostname); + send_req_key(from); + } + return true; + } + send_mtu_info(myself, from, MTU); + } + + return true; + } + + /* Requests that are not SPTPS data packets are forwarded as-is. */ + + if (to != myself) + return send_request(to->nexthop->connection, "%s", request); + + /* The request is for us */ + + switch(reqno) { + case REQ_PUBKEY: { + if(!node_read_ecdsa_public_key(from)) { + /* Request their key *before* we send our key back. Otherwise the first SPTPS packet from them will get dropped. */ + logger(DEBUG_PROTOCOL, LOG_DEBUG, "Preemptively requesting Ed25519 key for %s (%s)", from->name, from->hostname); + send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY); + } + char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa); + send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey); + free(pubkey); + return true; + } + + case ANS_PUBKEY: { + if(node_read_ecdsa_public_key(from)) { + logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname); + 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(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey"); + return true; + } + + logger(DEBUG_PROTOCOL, LOG_INFO, "Learned Ed25519 public key from %s (%s)", from->name, from->hostname); + append_config_file(from->name, "Ed25519PublicKey", pubkey); + return true; + } + + case REQ_KEY: { + if(!node_read_ecdsa_public_key(from)) { + logger(DEBUG_PROTOCOL, LOG_DEBUG, "No Ed25519 key known for %s (%s)", from->name, from->hostname); + send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY); + return true; + } + + if(from->sptps.label) + logger(DEBUG_ALWAYS, LOG_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name); + + 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(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS_START", from->name, from->hostname, "invalid SPTPS data"); + return true; + } + + char label[25 + strlen(from->name) + strlen(myself->name)]; + snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name); + sptps_stop(&from->sptps); + from->status.validkey = false; + from->status.waitingforkey = true; + from->last_req_key = now.tv_sec; + sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data_myself, receive_sptps_record); + sptps_receive_data(&from->sptps, buf, len); + send_mtu_info(myself, from, MTU); + return true; + } + + default: + logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request); + return true; + } +} + +bool req_key_h(connection_t *c, const char *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, + if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) { + logger(DEBUG_ALWAYS, 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"); + logger(DEBUG_ALWAYS, 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", + logger(DEBUG_ALWAYS, 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; } @@ -119,67 +264,93 @@ bool req_key_h(connection_t *c) { 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", + logger(DEBUG_ALWAYS, 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(to == myself) { /* Yes */ + /* Is this an extended REQ_KEY message? */ + if(experimental && reqno) + return req_key_ext_h(c, request, from, to, reqno); + + /* No, just send our key back */ 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", + logger(DEBUG_PROTOCOL, 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", c->buffer); + /* Is this an extended REQ_KEY message? */ + if(experimental && reqno) + return req_key_ext_h(c, request, from, to, reqno); + + send_request(to->nexthop->connection, "%s", request); } return true; } bool send_ans_key(node_t *to) { - char *key; + if(to->status.sptps) + abort(); + +#ifdef DISABLE_LEGACY + return false; +#else + size_t keylen = myself->incipher ? cipher_keylength(myself->incipher) : 1; + char key[keylen * 2 + 1]; + + randomize(key, keylen); + + cipher_close(to->incipher); + digest_close(to->indigest); + + if(myself->incipher) { + to->incipher = cipher_open_by_nid(cipher_get_nid(myself->incipher)); + if(!to->incipher) + abort(); + if(!cipher_set_key(to->incipher, key, false)) + abort(); + } - // Set key parameters - to->incipher = myself->incipher; - to->inkeylength = myself->inkeylength; - to->indigest = myself->indigest; - to->inmaclength = myself->inmaclength; - to->incompression = myself->incompression; + if(myself->indigest) { + to->indigest = digest_open_by_nid(digest_get_nid(myself->indigest), digest_length(myself->indigest)); + if(!to->indigest) + abort(); + if(!digest_set_key(to->indigest, key, keylen)) + abort(); + } - // Allocate memory for key - to->inkey = xrealloc(to->inkey, to->inkeylength); + to->incompression = myself->incompression; - // 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); + bin2hex(key, key, keylen); // Reset sequence number and late packet window mykeyused = true; to->received_seqno = 0; - memset(to->late, 0, sizeof(to->late)); + to->received = 0; + if(replaywin) memset(to->late, 0, replaywin); - // Convert to hexadecimal and send - key = alloca(2 * to->inkeylength + 1); - bin2hex(to->inkey, key, to->inkeylength); - key[to->inkeylength * 2] = '\0'; + to->status.validkey_in = true; 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); + myself->name, to->name, key, + cipher_get_nid(to->incipher), + digest_get_nid(to->indigest), + (int)digest_length(to->indigest), + to->incompression); +#endif } -bool ans_key_h(connection_t *c) { +bool ans_key_h(connection_t *c, const char *request) { char from_name[MAX_STRING_SIZE]; char to_name[MAX_STRING_SIZE]; char key[MAX_STRING_SIZE]; @@ -188,23 +359,23 @@ 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, + 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, + logger(DEBUG_ALWAYS, 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"); + logger(DEBUG_ALWAYS, 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", + logger(DEBUG_ALWAYS, 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; } @@ -212,7 +383,7 @@ bool ans_key_h(connection_t *c) { 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", + logger(DEBUG_ALWAYS, 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; } @@ -224,96 +395,123 @@ bool ans_key_h(connection_t *c) { 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); + logger(DEBUG_ALWAYS, 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) { + if(!*address && from->address.sa.sa_family != AF_UNSPEC && to->minmtu) { char *address, *port; - ifdebug(PROTOCOL) logger(LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name); + logger(DEBUG_PROTOCOL, 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", c->buffer, 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", c->buffer); + return send_request(to->nexthop->connection, "%s", request); } - /* Update our copy of the origin's packet key */ - from->outkey = xrealloc(from->outkey, strlen(key) / 2); - - from->outkey = xstrdup(key); - from->outkeylength = strlen(key) / 2; - hex2bin(key, from->outkey, from->outkeylength); +#ifndef DISABLE_LEGACY + /* Don't use key material until every check has passed. */ + cipher_close(from->outcipher); + digest_close(from->outdigest); +#endif + if (!from->status.sptps) from->status.validkey = false; - /* Check and lookup cipher and digest algorithms */ + if(compression < 0 || compression > 11) { + logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname); + return true; + } - if(cipher) { - from->outcipher = EVP_get_cipherbynid(cipher); + from->outcompression = compression; - if(!from->outcipher) { - logger(LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, - from->hostname); + /* SPTPS or old-style key exchange? */ + + if(from->status.sptps) { + char buf[strlen(key)]; + int len = b64decode(key, buf, strlen(key)); + if(!len || !sptps_receive_data(&from->sptps, buf, len)) { + /* Uh-oh. It might be that the tunnel is stuck in some corrupted state, + so let's restart SPTPS in case that helps. But don't do that too often + to prevent storms. + Note that simply relying on handshake timeout is not enough, because + that doesn't apply to key regeneration. */ + if(from->last_req_key < now.tv_sec - 10) { + logger(DEBUG_PROTOCOL, LOG_ERR, "Failed to decode handshake TCP packet from %s (%s), restarting SPTPS", from->name, from->hostname); + send_req_key(from); + } return true; } - 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; + if(from->status.validkey) { + if(*address && *port) { + logger(DEBUG_PROTOCOL, 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); + } } - } else { - from->outcipher = NULL; - } - from->outmaclength = maclength; + send_mtu_info(myself, from, MTU); - if(digest) { - from->outdigest = EVP_get_digestbynid(digest); + return true; + } - if(!from->outdigest) { - logger(LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, - from->hostname); - return true; +#ifdef DISABLE_LEGACY + logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses legacy protocol!", from->name, from->hostname); + return false; +#else + /* Check and lookup cipher and digest algorithms */ + + if(cipher) { + if(!(from->outcipher = cipher_open_by_nid(cipher))) { + logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname); + return false; } + } else { + from->outcipher = NULL; + } - 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; + if(digest) { + if(!(from->outdigest = digest_open_by_nid(digest, maclength))) { + logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname); + return false; } } else { from->outdigest = NULL; } - if(compression < 0 || compression > 11) { - logger(LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname); + if(maclength != digest_length(from->outdigest)) { + logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname); + return false; + } + + /* Process key */ + + int keylen = hex2bin(key, key, sizeof key); + + if(keylen != (from->outcipher ? cipher_keylength(from->outcipher) : 1)) { + logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname); return true; } - - 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; - } + /* Update our copy of the origin's packet key */ + + if(from->outcipher && !cipher_set_key(from->outcipher, key, true)) + return false; + if(from->outdigest && !digest_set_key(from->outdigest, key, keylen)) + return false; 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); + logger(DEBUG_PROTOCOL, 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 && !from->mtuprobes) - send_mtu_probe(from); - return true; +#endif }