From: Guus Sliepen Date: Fri, 22 Sep 2000 15:06:28 +0000 (+0000) Subject: - Severe code reduction and simplification of challenge requests X-Git-Tag: release-1.0pre3~107 X-Git-Url: https://tinc-vpn.org/git/browse?a=commitdiff_plain;h=5afc1e98f436c4a2ed5da4b64293275b09632c79;p=tinc - Severe code reduction and simplification of challenge requests - "Finished" [add|del]_subnet_h - Added lots of sanity checks to [add|del]_host_h --- diff --git a/src/protocol.c b/src/protocol.c index 35b07882..78ab00d7 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 1.28.4.33 2000/09/17 21:42:05 guus Exp $ + $Id: protocol.c,v 1.28.4.34 2000/09/22 15:06:28 guus Exp $ */ #include "config.h" @@ -133,17 +133,21 @@ cp int send_id(conn_list_t *cl) { + int x; + char *optstr; +cp + x = send_request(cl, "%d %s %d %s", ID, myself->name, myself->protocol_version, optstr=opt2str(myself->options)); + free(optstr); cp - return send_request(cl, "%d %s %d %s", ID, - myself->name, myself->protocol_version, opt2str(myself->options)); + return x; } int id_h(conn_list_t *cl) { conn_list_t *old; - char *options; + char *optstr; cp - if(sscanf(cl->buffer, "%*d %as %d %as", &cl->name, &cl->protocol_version, &options) != 3) + if(sscanf(cl->buffer, "%*d %as %d %as", &cl->name, &cl->protocol_version, &optstr) != 3) { syslog(LOG_ERR, _("Got bad ID from %s"), cl->hostname); return -1; @@ -160,12 +164,15 @@ cp /* Check if option string is valid */ - if((cl->options = str2opt(options)) == -1) + if((cl->options = str2opt(optstr)) == -1) { syslog(LOG_ERR, _("Peer %s uses invalid option string"), cl->hostname); + free(optstr); return -1; } + free(optstr); + /* Check if identity is a valid name */ if(!check_id(cl->name)) @@ -210,111 +217,76 @@ cp int send_challenge(conn_list_t *cl) { - char *buffer; - int keylength; - int x; + char buffer[CHAL_LENGTH*2+1]; cp - if(cl->chal_answer) - free(cl->chal_answer); - - /* Allocate buffers for the challenge and the hash */ + /* Allocate buffers for the challenge */ - cl->chal_answer = xmalloc(SHA_DIGEST_LENGTH); - keylength = BN_num_bytes(cl->rsakey->length); - buffer = xmalloc(keylength*2); + if(!cl->hischallenge) + cl->hischallenge = xmalloc(CHAL_LENGTH); - /* Copy random data and the public key to the buffer */ + /* Copy random data to the buffer */ - RAND_bytes(buffer, keylength); - BN_bn2bin(cl->rsakey->length, buffer+keylength); - - /* If we don't have a blowfish key set yet, use the random data from the challenge to do so. */ - - if(!cl->status.encryptin) - { - set_metakey(cl, buffer, keylength); - } - - /* Calculate the hash from that */ - - SHA1(buffer, keylength*2, cl->chal_answer); + RAND_bytes(cl->hischallenge, CHAL_LENGTH); /* Convert the random data to a hexadecimal formatted string */ - bin2hex(buffer,buffer,keylength); + bin2hex(cl->hischallenge,buffer,CHAL_LENGTH); buffer[keylength*2] = '\0'; /* Send the challenge */ cl->allow_request = CHAL_REPLY; - x = send_request(cl, "%d %s", CHALLENGE, buffer); - free(buffer); - cl->status.encryptout = 1; cp - return x; + return send_request(cl, "%d %s", CHALLENGE, buffer); } int challenge_h(conn_list_t *cl) { - char *challenge; - int x; - + char *buffer; cp - if(sscanf(cl->buffer, "%*d %as", &cl->name, &challenge) != 1) + if(sscanf(cl->buffer, "%*d %as", &buffer) != 1) { syslog(LOG_ERR, _("Got bad CHALLENGE from %s (%s)"), cl->name, cl->hostname); return -1; } - /* Rest is done by send_chal_reply() */ - - x = send_chal_reply(cl, challenge); - free(challenge); -cp - return x; -} - -int send_chal_reply(conn_list_t *cl, char *challenge) -{ - char *buffer; - int keylength; - char *hash; - int x; - -cp - keylength = BN_num_bytes(myself->rsakey->length); - /* Check if the length of the challenge is all right */ - if(strlen(challenge) != keylength*2) + if(strlen(buffer) != CHAL_LENGTH*2) { syslog(LOG_ERR, _("Intruder: wrong challenge length from %s (%s)"), cl->name, cl->hostname); + free(buffer); return -1; } - /* Allocate buffers for the challenge and the hash */ - - buffer = xmalloc(keylength*2); - hash = xmalloc(SHA_DIGEST_LENGTH*2+1); - - /* Copy the incoming random data and our public key to the buffer */ - - hex2bin(challenge, buffer, keylength); - BN_bn2bin(myself->rsakey->length, buffer+keylength); + /* Allocate buffers for the challenge */ - /* Calculate the hash from that */ + if(!cl->mychallenge) + cl->mychallenge = xmalloc(CHAL_LENGTH); - SHA1(buffer, keylength*2, hash); + /* Convert the challenge from hexadecimal back to binary */ - /* If we don't have a blowfish key set yet, use the random data from the challenge to do so. */ + hex2bin(buffer,cl->mychallenge,CHAL_LENGTH); + free(buffer); + + /* Rest is done by send_chal_reply() */ +cp + return send_chal_reply(cl); +} - if(!cl->status.encrypted) +int send_chal_reply(conn_list_t *cl) +{ + char hash[SHA_DIGEST_LENGTH*2+1]; +cp + if(!cl->mychallenge) { - set_metakey(cl, buffer, keylength); - cl->status.encrypted = 1; + syslog(LOG_ERR, _("Trying to send CHAL_REPLY to %s (%s) without a valid CHALLENGE"), cl->name, cl->hostname); + return -1; } + + /* Calculate the hash from the challenge we received */ - free(buffer); + SHA1(cl->mychallenge, CHAL_LENGTH, hash); /* Convert the hash to a hexadecimal formatted string */ @@ -328,17 +300,16 @@ cp else cl->allow_request = ACK; - x = send_request(cl, "%d %s", CHAL_REPLY, hash); - free(hash); cp - return x; + return send_request(cl, "%d %s", CHAL_REPLY, hash); } int chal_reply_h(conn_list_t *cl) { - char *hash; + char *hishash; + char myhash[SHA_DIGEST_LENGTH]; cp - if(sscanf(cl->buffer, "%*d %as", &cl->name, &hash) != 2) + if(sscanf(cl->buffer, "%*d %as", &hishash) != 2) { syslog(LOG_ERR, _("Got bad CHAL_REPLY from %s (%s)"), cl->name, cl->hostname); return -1; @@ -346,7 +317,7 @@ cp /* Check if the length of the hash is all right */ - if(strlen(hash) != SHA_DIGEST_LENGTH*2) + if(strlen(hishash) != SHA_DIGEST_LENGTH*2) { syslog(LOG_ERR, _("Intruder: wrong challenge reply length from %s (%s)"), cl->name, cl->hostname); return -1; @@ -354,24 +325,27 @@ cp /* Convert the hash to binary format */ - hex2bin(hash, hash, SHA_DIGEST_LENGTH); + hex2bin(hishash, hishash, SHA_DIGEST_LENGTH); + + /* Calculate the hash from the challenge we sent */ + + SHA1(cl->hischallenge, CHAL_LENGTH, myhash); /* Verify the incoming hash with the calculated hash */ - if(!memcmp(hash, cl->chal_answer, SHA_DIGEST_LENGTH)) + if(!memcmp(hishash, myhash, SHA_DIGEST_LENGTH)) { syslog(LOG_ERR, _("Intruder: wrong challenge reply from %s (%s)"), cl->name, cl->hostname); + free(hishash); return -1; } + free(hishash); + /* Identity has now been positively verified. If we are accepting this new connection, then send our identity, if we are making this connecting, acknowledge. */ - - free(hash); - free(cl->chal_answer); - cp if(cl->status.outgoing) { @@ -394,10 +368,9 @@ cp int ack_h(conn_list_t *cl) { conn_list_t *old; - cp /* Okay, before we active the connection, we check if there is another entry - in the connection list with the same vpn_ip. If so, it presumably is an + in the connection list with the same name. If so, it presumably is an old connection that has timed out but we don't know it yet. */ @@ -436,9 +409,14 @@ cp int send_add_subnet(conn_list_t *cl, conn_list_t *other, subnet_t *subnet) { + int x; + char *netstr; cp - return send_request(cl, "%d %s %s", ADD_SUBNET, - other->name, net2str(subnet)); + x = send_request(cl, "%d %s %s", ADD_SUBNET, + other->name, netstr = net2str(subnet)); + free(netstr); +cp + return x; } int add_subnet_h(conn_list_t *cl) @@ -450,8 +428,9 @@ int add_subnet_h(conn_list_t *cl) cp if(sscanf(cl->buffer, "%*d %as %as", &name, &subnetstr) != 3) { - syslog(LOG_ERR, _("Got bad ADD_SUBNET from %s (%s)"), cl->name, cl->hostname); - return -1; + syslog(LOG_ERR, _("Got bad ADD_SUBNET from %s (%s)"), cl->name, cl->hostname); + free(name); free(subnetstr); + return -1; } /* Check if owner name is a valid */ @@ -459,6 +438,7 @@ cp if(!check_id(name)) { syslog(LOG_ERR, _("Got bad ADD_SUBNET from %s (%s): invalid identity name"), cl->name, cl->hostname); + free(name); free(subnetstr); return -1; } @@ -467,8 +447,11 @@ cp if((subnet = str2net(subnetstr)) == -1) { syslog(LOG_ERR, _("Got bad ADD_SUBNET from %s (%s): invalid subnet string"), cl->name, cl->hostname); + free(name); free(subnetstr); return -1; } + + free(subnetstr); /* Check if somebody tries to add a subnet of ourself */ @@ -476,6 +459,7 @@ cp { syslog(LOG_ERR, _("Warning: got ADD_SUBNET from %s (%s) for ourself, restarting"), cl->name, cl->hostname); + free(name); sighup = 1; return 0; } @@ -484,11 +468,15 @@ cp if(!(owner = lookup_id(name)) { - syslog(LOG_NOTICE, _("Got ADD_SUBNET for %s from %s (%s) which is not in our connection list"), + syslog(LOG_ERR, _("Got ADD_SUBNET for %s from %s (%s) which is not in our connection list"), name, cl->name, cl->hostname); + free(name); + return -1; } - + /* If everything is correct, add the subnet to the list of the owner */ +cp + return subnet_add(owner, subnet); } int send_del_subnet(conn_list_t *cl, conn_list_t *other, subnet_t *subnet) @@ -506,8 +494,9 @@ int del_subnet_h(conn_list_t *cl) cp if(sscanf(cl->buffer, "%*d %as %as", &name, &subnetstr) != 3) { - syslog(LOG_ERR, _("Got bad DEL_SUBNET from %s (%s)"), cl->name, cl->hostname); - return -1; + syslog(LOG_ERR, _("Got bad DEL_SUBNET from %s (%s)"), cl->name, cl->hostname); + free(name); free(subnetstr); + return -1; } /* Check if owner name is a valid */ @@ -515,6 +504,7 @@ cp if(!check_id(name)) { syslog(LOG_ERR, _("Got bad DEL_SUBNET from %s (%s): invalid identity name"), cl->name, cl->hostname); + free(name); free(subnetstr); return -1; } @@ -523,15 +513,19 @@ cp if((subnet = str2net(subnetstr)) == -1) { syslog(LOG_ERR, _("Got bad DEL_SUBNET from %s (%s): invalid subnet string"), cl->name, cl->hostname); + free(name); free(subnetstr); return -1; } - /* Check if somebody tries to delete a subnet of ourself */ + free(subnetstr); + + /* Check if somebody tries to add a subnet of ourself */ if(!strcmp(name, myself->name)) { syslog(LOG_ERR, _("Warning: got DEL_SUBNET from %s (%s) for ourself, restarting"), cl->name, cl->hostname); + free(name); sighup = 1; return 0; } @@ -540,27 +534,40 @@ cp if(!(owner = lookup_id(name)) { - syslog(LOG_NOTICE, _("Got DEL_SUBNET for %s from %s (%s) which is not in our connection list"), + syslog(LOG_ERR, _("Got DEL_SUBNET for %s from %s (%s) which is not in our connection list"), name, cl->name, cl->hostname); + free(name); + return -1; } + + /* If everything is correct, add the subnet to the list of the owner */ +cp + return subnet_del(owner, subnet); } /* New and closed connections notification */ int send_add_host(conn_list_t *cl, conn_list_t *other) { + char *optstr; + int x; +cp + x = send_request(cl, "%d %s %s %lx:%d %s", ADD_HOST, + myself->name, other->name, other->real_ip, other->port, optstr = opt2str(other->options)); + free(optstr); cp - return send_request(cl, "%d %s %lx:%d %s", ADD_HOST, other->name, other->real_ip, other->port, opt2str(other->options)); + return x; } int add_host_h(conn_list_t *cl) { - char *options; - conn_list_t *old, *new; + char *optstr; + char *sender; + conn_list_t *old, *new, *hisuplink; cp new = new_conn_list(); - if(sscanf(cl->buffer, "%*d %as %lx:%d %as", &new->name, &new->real_ip, &new->port, &options) != 4) + if(sscanf(cl->buffer, "%*d %as %as %lx:%d %as", &sender, &new->name, &new->address, &new->port, &optstr) != 5) { syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s)"), cl->name, cl->hostname); return -1; @@ -568,17 +575,21 @@ cp /* Check if option string is valid */ - if((new->options = str2opt(options)) == -1) + if((new->options = str2opt(optstr)) == -1) { syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s): invalid option string"), cl->name, cl->hostname); + free(optstr); free(sender); return -1; } + free(optstr); + /* Check if identity is a valid name */ - if(!check_id(new->name)) + if(!check_id(new->name) || !check_id(sender)) { syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s): invalid identity name"), cl->name, cl->hostname); + free(sender); return -1; } @@ -588,9 +599,32 @@ cp { syslog(LOG_ERR, _("Warning: got ADD_HOST from %s (%s) for ourself, restarting"), cl->name, cl->hostname); sighup = 1; + free(sender); return 0; } + /* We got an ADD_HOST from ourself!? */ + + if(!strcmp(sender, myself->name)) + { + syslog(LOG_ERR, _("Warning: got ADD_HOST from %s (%s) from ourself, restarting"), cl->name, cl->hostname); + sighup = 1; + free(sender); + return 0; + } + + /* Lookup his uplink */ + + if(!(new->hisuplink = lookup_id(sender)) + { + syslog(LOG_ERR, _("Got ADD_HOST from %s (%s) with origin %s which is not in our connection list"), + sender, cl->name, cl->hostname); + free(sender); + return -1; + } + + free(sender); + /* Fill in more of the new conn_list structure */ new->hostname = hostlookup(htonl(new->real_ip)); @@ -618,7 +652,7 @@ cp /* Fill in rest of conn_list structure */ - new->nexthop = cl; + new->myuplink = cl; new->status.active = 1; /* Hook it up into the conn_list */ @@ -635,58 +669,111 @@ cp int send_del_host(conn_list_t *cl, conn_list_t *other) { + char *optstr; + int x; cp - return send_request(cl, "%d %s %lx:%d", DEL_HOST, - other->name, other->real_ip, other->port); + x = send_request(cl, "%d %s %s %lx:%d %s", DEL_HOST, + myself->name, other->name, other->real_ip, other->port, optstr = opt2str(other->options)); + free(optstr); +cp + return x; } int del_host_h(conn_list_t *cl) { - char *id; + char *name; + char *sender; + char *opstr; ip_t address; port_t port; - conn_list_t *old; + int options; + conn_list_t *old, *hisuplink; cp - if(sscanf(cl->buffer, "%*d %as %lx:%d", &id, &address, &port) != 3) + if(sscanf(cl->buffer, "%*d %as %as %lx:%d %as", &sender, &name, &address, &port, &optstr) != 5) { syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s)"), cl->name, cl->hostname); return -1; } + /* Check if option string is valid */ + + if((options = str2opt(optstr)) == -1) + { + syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s): invalid option string"), cl->name, cl->hostname); + free(optstr); free(sender); free(name); + return -1; + } + + free(optstr); + + /* Check if identity is a valid name */ + + if(!check_id(name) || !check_id(sender)) + { + syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s): invalid identity name"), cl->name, cl->hostname); + free(name); free(sender); + return -1; + } + /* Check if somebody tries to delete ourself */ - if(!strcmp(id, myself->name)) + if(!strcmp(name, myself->name)) { syslog(LOG_ERR, _("Warning: got DEL_HOST from %s (%s) for ourself, restarting"), cl->name, cl->hostname); + free(name); free(sender); sighup = 1; return 0; } - /* Check if the new host already exists in the connnection list */ + /* We got an ADD_HOST from ourself!? */ - if((old = lookup_id(id))) + if(!strcmp(sender, myself->name)) { - if((address == old->real_ip) && (port == old->port)) - { - notify_others(old, cl, send_del_host); + syslog(LOG_ERR, _("Warning: got DEL_HOST from %s (%s) from ourself, restarting"), cl->name, cl->hostname); + sighup = 1; + free(name); free(sender); + return 0; + } - old->status.termreq = 1; - old->status.active = 0; + /* Lookup his uplink */ - terminate_connection(old); -cp - return 0; - } + if(!(hisuplink = lookup_id(sender)) + { + syslog(LOG_ERR, _("Got DEL_HOST from %s (%s) with origin %s which is not in our connection list"), + cl->name, cl->hostname, sender); + free(name); free(sender); + return -1; } + + free(sender); - if(debug_lvl > DEBUG_CONNECTIONS) + /* Check if the new host already exists in the connnection list */ + + if(!(old = lookup_id(name))) { - syslog(LOG_NOTICE, _("Got DEL_HOST for %s from %s (%s) which is not in our connection list"), - id, cl->name, cl->hostname); + syslog(LOG_ERR, _("Got DEL_HOST from %s (%s) for %s which is not in our connection list"), + name, cl->name, cl->hostname); + free(name); + return -1; } + + /* Check if the rest matches */ + + if(address!=old->address || port!=old->port || options!=old->options || hisuplink!=old->hisuplink || cl!=old->myuplink) + { + syslog(LOG_WARNING, _("Got DEL_HOST from %s (%s) for %s which doesn't match"), cl->name, cl->hostname, old->name); + return 0; + } + + /* Ok, since EVERYTHING seems to check out all right, delete it */ + + old->status.termreq = 1; + old->status.active = 0; + + terminate_connection(old); cp return 0; }