X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fprotocol.c;h=492f2893878f11910cdc6084981c9649c1523125;hp=cd63ad0b094ac5b684d57c4e01a03defd3be8c51;hb=fcc3ded75fe9f831aeb8678ee5e3926bf4168906;hpb=e4f3d93ec62871d1ae11b460627aef0da1b23cd2 diff --git a/src/protocol.c b/src/protocol.c index cd63ad0b..492f2893 100644 --- a/src/protocol.c +++ b/src/protocol.c @@ -17,7 +17,7 @@ along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - $Id: protocol.c,v 1.28.4.87 2001/05/07 19:08:46 guus Exp $ + $Id: protocol.c,v 1.28.4.108 2001/10/08 15:37:14 guus Exp $ */ #include "config.h" @@ -40,25 +40,14 @@ #include -#ifdef HAVE_OPENSSL_SHA_H -# include -#else -# include -#endif - -#ifdef HAVE_OPENSSL_RAND_H -# include -#else -# include -#endif +#include +#include +#include -#ifdef HAVE_OPENSSL_EVP_H -# include -#else -# include +#ifndef HAVE_RAND_PSEUDO_BYTES +#define RAND_pseudo_bytes RAND_bytes #endif - #include "conf.h" #include "net.h" #include "netutl.h" @@ -68,6 +57,8 @@ #include "system.h" +int mykeyused = 0; + int check_id(char *id) { int i; @@ -104,11 +95,15 @@ cp return -1; } - len++; - if(debug_lvl >= DEBUG_PROTOCOL) - syslog(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request], cl->name, cl->hostname); + { + if(debug_lvl >= DEBUG_META) + syslog(LOG_DEBUG, _("Sending %s to %s (%s): %s"), request_name[request], cl->name, cl->hostname, buffer); + else + syslog(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request], cl->name, cl->hostname); + } + buffer[len++] = '\n'; cp return send_meta(cl, buffer, len); } @@ -116,20 +111,31 @@ cp int receive_request(connection_t *cl) { int request; -cp +cp if(sscanf(cl->buffer, "%d", &request) == 1) { if((request < 0) || (request >= LAST) || (request_handlers[request] == NULL)) { - syslog(LOG_ERR, _("Unknown request from %s (%s)"), - cl->name, cl->hostname); + if(debug_lvl >= DEBUG_META) + syslog(LOG_DEBUG, _("Unknown request from %s (%s): %s"), + cl->name, cl->hostname, cl->buffer); + else + syslog(LOG_ERR, _("Unknown request from %s (%s)"), + cl->name, cl->hostname); + return -1; } else { if(debug_lvl >= DEBUG_PROTOCOL) - syslog(LOG_DEBUG, _("Got %s from %s (%s)"), - request_name[request], cl->name, cl->hostname); + { + if(debug_lvl >= DEBUG_META) + syslog(LOG_DEBUG, _("Got %s from %s (%s): %s"), + request_name[request], cl->name, cl->hostname, cl->buffer); + else + syslog(LOG_DEBUG, _("Got %s from %s (%s)"), + request_name[request], cl->name, cl->hostname); + } } if((cl->allow_request != ALL) && (cl->allow_request != request)) @@ -156,34 +162,8 @@ cp return 0; } -/* Connection protocol: - - Client Server - send_id(u) - send_challenge(R) - send_chal_reply(H) - send_id(u) - send_challenge(R) - send_chal_reply(H) - --------------------------------------- - send_metakey(R) - send_metakey(R) - --------------------------------------- - send_ack(u) - send_ack(u) - --------------------------------------- - Other requests(E)... - - (u) Unencrypted, - (R) RSA, - (H) SHA1, - (E) Encrypted with symmetric cipher. - - Part of the challenge is directly used to set the symmetric cipher - key and the initial vector. Since a man-in-the-middle cannot - decrypt the RSA challenges, this means that he cannot get or forge - the key for the symmetric cipher. -*/ +/* The authentication protocol is described in detail in doc/SECURITY2, + the rest will be described in doc/PROTOCOL. */ int send_id(connection_t *cl) { @@ -193,12 +173,9 @@ cp int id_h(connection_t *cl) { - connection_t *old; - unsigned short int port; char name[MAX_STRING_SIZE]; - avl_node_t *node; cp - if(sscanf(cl->buffer, "%*d "MAX_STRING" %d %lx %hd", name, &cl->protocol_version, &cl->options, &port) != 4) + if(sscanf(cl->buffer, "%*d "MAX_STRING" %d %lx %hd", name, &cl->protocol_version, &cl->options, &cl->port) != 4) { syslog(LOG_ERR, _("Got bad ID from %s"), cl->hostname); return -1; @@ -223,6 +200,9 @@ cp /* Copy string to cl */ + if(cl->name) + free(cl->name); + cl->name = xstrdup(name); /* Load information about peer */ @@ -233,34 +213,6 @@ cp return -1; } - /* First check if the host we connected to is already in our - connection list. If so, we are probably making a loop, which - is not desirable. - */ - - if(cl->status.outgoing) - { - if((old = lookup_id(cl->name))) - { - if(debug_lvl >= DEBUG_CONNECTIONS) - syslog(LOG_NOTICE, _("Uplink %s (%s) is already in our connection list"), cl->name, cl->hostname); - cl->status.outgoing = 0; - old->status.outgoing = 1; - terminate_connection(cl); - return 0; - } - } - - /* Now we can add the name to the id tree */ - - id_add(cl); - - /* And uhr... cl->port just changed so we have to unlink it from the connection tree and re-insert... */ - - node = avl_unlink(connection_tree, cl); - cl->port = port; - avl_insert_node(connection_tree, node); - /* Read in the public key, so that we can send a metakey */ if(read_rsa_public_key(cl)) @@ -283,26 +235,45 @@ cp old connection that has timed out but we don't know it yet. */ - while((old = lookup_id(cl->name))) + if((old = lookup_id(cl->name))) { if(debug_lvl >= DEBUG_CONNECTIONS) - syslog(LOG_NOTICE, _("Removing old entry for %s at %s in favour of new connection from %s"), - cl->name, old->hostname, cl->hostname); + syslog(LOG_NOTICE, _("Removing old connection for %s at %s in favour of new connection at %s"), + old->name, old->hostname, cl->hostname); + if(old->status.outgoing) + { + cl->status.outgoing = 1; + old->status.outgoing = 0; + } - terminate_connection(old); + terminate_connection(old, 0); } - + + /* Also check if no other tinc daemon uses the same IP and port for UDP traffic */ + + old = avl_search(active_tree, cl); + if(old) + { + syslog(LOG_ERR, _("%s is listening on %s:%hd, which is already in use by %s!"), + cl->name, cl->hostname, cl->port, old->name); + return -1; + } + /* Activate this connection */ cl->allow_request = ALL; - cl->status.active = 1; cl->nexthop = cl; + cl->prevhop = myself; cl->cipher_pkttype = EVP_bf_cbc(); cl->cipher_pktkeylength = cl->cipher_pkttype->key_len + cl->cipher_pkttype->iv_len; + active_add(cl); + if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), cl->name, cl->hostname); + if(cl->status.outgoing) + seconds_till_retry = 5; /* Reset retry timeout */ cp /* Check some options */ @@ -318,6 +289,11 @@ cp cl->options |= OPTION_TCPONLY; } + if((myself->options | cl->options) & OPTION_INDIRECT) + cl->via = myself; + else + cl->via = cl; + /* Send him our subnets */ for(node = myself->subnet_tree->head; node; node = node->next) @@ -328,11 +304,11 @@ cp /* And send him all the hosts and their subnets we know... */ - for(node = connection_tree->head; node; node = node->next) + for(node = active_tree->head; node; node = node->next) { p = (connection_t *)node->data; - if(p != cl && p->status.active) + if(p != cl) { /* Notify others of this connection */ @@ -349,7 +325,7 @@ cp send_add_subnet(cl, subnet); } } - } + } cp return 0; } @@ -645,10 +621,7 @@ int send_add_subnet(connection_t *cl, subnet_t *subnet) char *netstr; char *owner; cp - if((cl->options | myself->options | subnet->owner->options) & OPTION_INDIRECT) - owner = myself->name; - else - owner = subnet->owner->name; + owner = subnet->owner->name; x = send_request(cl, "%d %s %s", ADD_SUBNET, owner, netstr = net2str(subnet)); @@ -715,7 +688,7 @@ cp for(node = connection_tree->head; node; node = node->next) { p = (connection_t *)node->data; - if(p->status.meta && p->status.active && p!= cl) + if(p->status.active && p!= cl) send_add_subnet(p, subnet); } cp @@ -728,10 +701,7 @@ int send_del_subnet(connection_t *cl, subnet_t *subnet) char *netstr; char *owner; cp - if(cl->options & OPTION_INDIRECT) - owner = myself->name; - else - owner = subnet->owner->name; + owner = subnet->owner->name; x = send_request(cl, "%d %s %s", DEL_SUBNET, owner, netstr = net2str(subnet)); free(netstr); @@ -799,7 +769,7 @@ cp for(node = connection_tree->head; node; node = node->next) { p = (connection_t *)node->data; - if(p->status.meta && p->status.active && p!= cl) + if(p->status.active && p!= cl) send_del_subnet(p, subnet); } cp @@ -811,22 +781,19 @@ cp int send_add_host(connection_t *cl, connection_t *other) { cp - if(!((cl->options | myself->options | other->options) & OPTION_INDIRECT)) - return send_request(cl, "%d %s %lx:%d %lx", ADD_HOST, - other->name, other->address, other->port, other->options); - else - return 0; + return send_request(cl, "%d %s %lx:%d %lx %s", ADD_HOST, + other->name, other->address, other->port, other->options, other->prevhop->name); } int add_host_h(connection_t *cl) { connection_t *old, *new, *p; - char name[MAX_STRING_SIZE]; + char name[MAX_STRING_SIZE], prevhop[MAX_STRING_SIZE]; avl_node_t *node; cp new = new_connection(); - if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%hd %lx", name, &new->address, &new->port, &new->options) != 4) + if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%hd %lx "MAX_STRING, name, &new->address, &new->port, &new->options, prevhop) != 5) { syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s)"), cl->name, cl->hostname); return -1; @@ -841,63 +808,81 @@ cp return -1; } + if(check_id(prevhop)) + { + syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s): invalid prevhop name"), cl->name, cl->hostname); + free_connection(new); + return -1; + } + /* Check if somebody tries to add ourself */ if(!strcmp(name, myself->name)) { - syslog(LOG_ERR, _("Warning: got ADD_HOST from %s (%s) for ourself, restarting"), cl->name, cl->hostname); - sighup = 1; + syslog(LOG_ERR, _("Got ADD_HOST from %s (%s) for ourself!"), cl->name, cl->hostname); free_connection(new); - return 0; + return -1; } /* Fill in more of the new connection structure */ new->hostname = hostlookup(htonl(new->address)); + new->prevhop = lookup_id(prevhop); + + if(!new->prevhop) + { + syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s): unknown prevhop"), cl->name, cl->hostname); + free_connection(new); + return -1; + } + /* Check if the new host already exists in the connnection list */ if((old = lookup_id(name))) { - if((new->address == old->address) && (new->port == old->port)) + if((new->address == old->address) && (new->port == old->port) && (cl->nexthop == old->nexthop)) { if(debug_lvl >= DEBUG_CONNECTIONS) syslog(LOG_NOTICE, _("Got duplicate ADD_HOST for %s (%s) from %s (%s)"), - old->name, old->hostname, name, new->hostname); + old->name, old->hostname, cl->name, cl->hostname); free_connection(new); return 0; } else { if(debug_lvl >= DEBUG_CONNECTIONS) - syslog(LOG_NOTICE, _("Removing old entry for %s (%s) in favour of new connection"), - old->name, old->hostname); + syslog(LOG_NOTICE, _("Removing old entry for %s (%s) from %s in favour of new connection from %s"), + old->name, old->hostname, old->nexthop->name, cl->nexthop->name); - terminate_connection(old); + terminate_connection(old, 0); } } - /* Hook it up into the connection */ + /* Hook it up into the active tree */ new->name = xstrdup(name); - connection_add(new); - id_add(new); + active_add(new); /* Tell the rest about the new host */ for(node = connection_tree->head; node; node = node->next) { p = (connection_t *)node->data; - if(p->status.meta && p->status.active && p!=cl) + if(p->status.active && p!=cl) send_add_host(p, new); } /* Fill in rest of connection structure */ new->nexthop = cl; - new->status.active = 1; new->cipher_pkttype = EVP_bf_cbc(); new->cipher_pktkeylength = cl->cipher_pkttype->key_len + cl->cipher_pkttype->iv_len; + + if(new->options & OPTION_INDIRECT || new->prevhop->via != new->prevhop) + new->via = new->prevhop->via; + else + new->via = new; cp return 0; } @@ -905,23 +890,20 @@ cp int send_del_host(connection_t *cl, connection_t *other) { cp - if(!((cl->options | myself->options) & OPTION_INDIRECT)) - return send_request(cl, "%d %s %lx:%d %lx", DEL_HOST, - other->name, other->address, other->port, other->options); - else - return 0; + return send_request(cl, "%d %s %lx:%d %lx %s", DEL_HOST, + other->name, other->address, other->port, other->options, other->prevhop->name); } int del_host_h(connection_t *cl) { - char name[MAX_STRING_SIZE]; + char name[MAX_STRING_SIZE], prevhop[MAX_STRING_SIZE]; ipv4_t address; port_t port; long int options; connection_t *old, *p; avl_node_t *node; cp - if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%hd %lx", name, &address, &port, &options) != 4) + if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%hd %lx "MAX_STRING, name, &address, &port, &options, prevhop) != 5) { syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s)"), cl->name, cl->hostname); @@ -936,28 +918,33 @@ cp return -1; } + if(check_id(prevhop)) + { + syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s): invalid prevhop name"), cl->name, cl->hostname); + return -1; + } + /* Check if somebody tries to delete ourself */ if(!strcmp(name, myself->name)) { - syslog(LOG_ERR, _("Warning: got DEL_HOST from %s (%s) for ourself, restarting"), + syslog(LOG_ERR, _("Got DEL_HOST from %s (%s) for ourself!"), cl->name, cl->hostname); - sighup = 1; - return 0; + return -1; } - /* Check if the new host already exists in the connnection list */ + /* Check if the deleted host already exists in the connnection list */ if(!(old = lookup_id(name))) { syslog(LOG_ERR, _("Got DEL_HOST from %s (%s) for %s which is not in our connection list"), - name, cl->name, cl->hostname); + cl->name, cl->hostname, name); return -1; } /* Check if the rest matches */ - if(address!=old->address || port!=old->port || options!=old->options || cl!=old->nexthop) + if(address!=old->address || port!=old->port || options!=old->options || cl!=old->nexthop || strcmp(prevhop, old->prevhop->name)) { syslog(LOG_WARNING, _("Got DEL_HOST from %s (%s) for %s which doesn't match"), cl->name, cl->hostname, old->name); return 0; @@ -965,15 +952,14 @@ cp /* Ok, since EVERYTHING seems to check out all right, delete it */ - old->status.active = 0; - terminate_connection(old); + terminate_connection(old, 0); - /* Tell the rest about the new host */ + /* Tell the rest about the deleted host */ for(node = connection_tree->head; node; node = node->next) { p = (connection_t *)node->data; - if(p->status.meta && p->status.active && p!=cl) + if(p->status.active && p!=cl) send_del_host(p, old); } cp @@ -1039,7 +1025,7 @@ cp cl->name, cl->hostname, strerror(err), errorstring); } - terminate_connection(cl); + terminate_connection(cl, cl->status.meta); cp return 0; } @@ -1053,18 +1039,22 @@ cp int termreq_h(connection_t *cl) { cp - terminate_connection(cl); + terminate_connection(cl, cl->status.meta); cp return 0; } int send_ping(connection_t *cl) { + char salt[SALTLEN*2+1]; cp cl->status.pinged = 1; cl->last_ping_time = time(NULL); + RAND_pseudo_bytes(salt, SALTLEN); + bin2hex(salt, salt, SALTLEN); + salt[SALTLEN*2] = '\0'; cp - return send_request(cl, "%d", PING); + return send_request(cl, "%d %s", PING, salt); } int ping_h(connection_t *cl) @@ -1075,8 +1065,13 @@ cp int send_pong(connection_t *cl) { + char salt[SALTLEN*2+1]; +cp + RAND_pseudo_bytes(salt, SALTLEN); + bin2hex(salt, salt, SALTLEN); + salt[SALTLEN*2] = '\0'; cp - return send_request(cl, "%d", PONG); + return send_request(cl, "%d %s", PONG, salt); } int pong_h(connection_t *cl) @@ -1094,12 +1089,18 @@ int send_key_changed(connection_t *from, connection_t *cl) connection_t *p; avl_node_t *node; cp + /* Only send this message if some other daemon requested our key previously. + This reduces unnecessary key_changed broadcasts. + */ + + if(from==myself && !mykeyused) + return 0; + for(node = connection_tree->head; node; node = node->next) { p = (connection_t *)node->data; - if(p != cl && p->status.meta && p->status.active) - if(!(p->options & OPTION_INDIRECT) || from == myself) - send_request(p, "%d %s", KEY_CHANGED, from->name); + if(p != cl && p->status.active) + send_request(p, "%d %s", KEY_CHANGED, from->name); } cp return 0; @@ -1127,8 +1128,7 @@ cp from->status.validkey = 0; from->status.waitingforkey = 0; - if(!(from->options | cl->options | myself->options) & OPTION_INDIRECT) - send_key_changed(from, cl); + send_key_changed(from, cl); cp return 0; } @@ -1163,11 +1163,12 @@ cp /* Check if this key request is for us */ - if(!strcmp(to_id, myself->name)) + if(!strcmp(to_id, myself->name)) /* Yes, send our own key back */ { bin2hex(myself->cipher_pktkey, pktkey, myself->cipher_pktkeylength); pktkey[myself->cipher_pktkeylength*2] = '\0'; send_ans_key(myself, from, pktkey); + mykeyused = 1; } else { @@ -1267,53 +1268,29 @@ int send_tcppacket(connection_t *cl, vpn_packet_t *packet) { int x; cp + /* Evil hack. */ + x = send_request(cl->nexthop, "%d %hd", PACKET, packet->len); if(x) return x; - - return send_meta(cl->nexthop, packet->data, packet->len); +cp + return send_meta(cl, packet->data, packet->len); } int tcppacket_h(connection_t *cl) { - vpn_packet_t packet; - char *p; - int todo, x; + short int len; cp - if(sscanf(cl->buffer, "%*d %hd", &packet.len) != 1) + if(sscanf(cl->buffer, "%*d %hd", &len) != 1) { syslog(LOG_ERR, _("Got bad PACKET from %s (%s)"), cl->name, cl->hostname); return -1; } - /* Evil hack. */ - - p = packet.data; - todo = packet.len; - - while(todo) - { - x = read(cl->meta_socket, p, todo); - - if(x<=0) - { - if(x==0) - syslog(LOG_NOTICE, _("Connection closed by %s (%s)"), cl->name, cl->hostname); - else - if(errno==EINTR || errno==EAGAIN) /* FIXME: select() or poll() or reimplement this evil hack */ - continue; - else - syslog(LOG_ERR, _("Error during reception of PACKET from %s (%s): %m"), cl->name, cl->hostname); - - return -1; - } - - todo -= x; - p += x; - } + /* Set reqlen to len, this will tell receive_meta() that a tcppacket is coming. */ - receive_packet(cl, &packet); + cl->tcplen = len; cp return 0; }