From: Guus Sliepen Date: Sun, 17 Sep 2000 21:42:05 +0000 (+0000) Subject: - Updated authentication scheme. X-Git-Tag: release-1.0pre3~108 X-Git-Url: https://git.tinc-vpn.org/git/browse?a=commitdiff_plain;h=5d0b3516d5e8a46ca2268bdb32657b72295501ec;p=tinc - Updated authentication scheme. - Removed all trailing spaces from all lines. - Added things to add_ and del_subnet_h. --- diff --git a/src/protocol.c b/src/protocol.c index 43638941..35b07882 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 1.28.4.32 2000/09/15 12:58:40 zarq Exp $ + $Id: protocol.c,v 1.28.4.33 2000/09/17 21:42:05 guus Exp $ */ #include "config.h" @@ -53,9 +53,9 @@ int check_id(char *id) for (i = 0; i < strlen(id); i++) { if(!isalpha(id[i]) && id[i] != '_') - { - return 0; - } + { + return 0; + } } return 1; @@ -66,26 +66,29 @@ int check_id(char *id) int send_request(conn_list_t *cl, const char *format, int request, /*args*/ ...) { va_list args; - char *buffer = NULL; + char buffer[MAXBUFSIZE+1]; int len; - + cp - if(debug_lvl >= DEBUG_PROTOCOL) - syslog(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request], cl->name, cl->hostname); + /* Use vsnprintf instead of vasprintf: faster, no memory fragmentation, cleanup is automatic, + and there is a limit on the input buffer anyway */ va_start(args, request); - len = vasprintf(&buffer, format, args); + len = vsnprintf(buffer, MAXBUFSIZE+1, format, args); va_end(args); - if(len < 0 || !buffer) + if(len < 0 || len > MAXBUFSIZE) { - syslog(LOG_ERR, _("Error during vasprintf(): %m")); + syslog(LOG_ERR, _("Output buffer overflow while sending %s to %s (%s)"), request_name[request], cl->name, cl->hostname); return -1; } if(debug_lvl >= DEBUG_META) - syslog(LOG_DEBUG, _("Sending meta data to %s (%s): %s"), - cl->name, cl->hostname, buffer); + syslog(LOG_DEBUG, _("Sending %s to %s (%s): %s"), request_name[request], + cl->name, cl->hostname, buffer); + else if(debug_lvl >= DEBUG_PROTOCOL) + syslog(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request], cl->name, cl->hostname); + if(cl->status.encryptin) { @@ -97,7 +100,7 @@ cp syslog(LOG_ERR, _("Sending meta data failed: %m")); return -1; } -cp +cp } /* Connection protocol: @@ -105,27 +108,34 @@ cp Client Server send_id(u) send_challenge(R) - send_chal_reply(BH) - send_id(B) - send_challenge(BR) - send_chal_reply(BH) - send_ack(B) - send_ack(B) + send_chal_reply(H) + send_id(u) + send_challenge(R) + send_chal_reply(H) + --------------------------------------- + Any negotations about the meta protocol + encryption go here(u). + --------------------------------------- + send_ack(u) + send_ack(u) + --------------------------------------- + Other requests(E)... (u) Unencrypted, (R) RSA, (H) SHA1, - (B) Blowfish. + (E) Encrypted with symmetric cipher. - Part of the challenge is directly used to set the blowfish key and the initial vector. - (Twee vliegen in één klap!) -*/ + 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. +*/ int send_id(conn_list_t *cl) { cp return send_request(cl, "%d %s %d %s", ID, - myself->name, myself->protocol_version, opt2str(myself->options)); + myself->name, myself->protocol_version, opt2str(myself->options)); } int id_h(conn_list_t *cl) @@ -138,34 +148,34 @@ cp syslog(LOG_ERR, _("Got bad ID from %s"), cl->hostname); return -1; } - + /* Check if version matches */ - + if(cl->protocol_version != myself->protocol_version) { syslog(LOG_ERR, _("Peer %s (%s) uses incompatible version %d"), - cl->name, cl->hostname, cl->protocol_version); + cl->name, cl->hostname, cl->protocol_version); return -1; } /* Check if option string is valid */ - + if((cl->options = str2opt(options)) == -1) { syslog(LOG_ERR, _("Peer %s uses invalid option string"), cl->hostname); return -1; } - + /* Check if identity is a valid name */ - + if(!check_id(cl->name)) { syslog(LOG_ERR, _("Peer %s uses invalid identity name"), cl->hostname); return -1; } - + /* Load information about peer */ - + if(!read_id(cl)) { syslog(LOG_ERR, _("Peer %s had unknown identity (%s)"), cl->hostname, cl->name); @@ -206,20 +216,20 @@ int send_challenge(conn_list_t *cl) cp if(cl->chal_answer) free(cl->chal_answer); - + /* Allocate buffers for the challenge and the hash */ - + cl->chal_answer = xmalloc(SHA_DIGEST_LENGTH); keylength = BN_num_bytes(cl->rsakey->length); buffer = xmalloc(keylength*2); /* Copy random data and the public key 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); @@ -235,7 +245,7 @@ cp buffer[keylength*2] = '\0'; /* Send the challenge */ - + cl->allow_request = CHAL_REPLY; x = send_request(cl, "%d %s", CHALLENGE, buffer); free(buffer); @@ -248,7 +258,7 @@ int challenge_h(conn_list_t *cl) { char *challenge; int x; - + cp if(sscanf(cl->buffer, "%*d %as", &cl->name, &challenge) != 1) { @@ -257,7 +267,7 @@ cp } /* Rest is done by send_chal_reply() */ - + x = send_chal_reply(cl, challenge); free(challenge); cp @@ -270,7 +280,7 @@ int send_chal_reply(conn_list_t *cl, char *challenge) int keylength; char *hash; int x; - + cp keylength = BN_num_bytes(myself->rsakey->length); @@ -283,21 +293,21 @@ cp } /* 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); + hex2bin(challenge, buffer, keylength); BN_bn2bin(myself->rsakey->length, buffer+keylength); /* Calculate the hash from that */ - + SHA1(buffer, keylength*2, hash); /* If we don't have a blowfish key set yet, use the random data from the challenge to do so. */ - + if(!cl->status.encrypted) { set_metakey(cl, buffer, keylength); @@ -322,7 +332,7 @@ cp free(hash); cp return x; -} +} int chal_reply_h(conn_list_t *cl) { @@ -335,19 +345,19 @@ cp } /* Check if the length of the hash is all right */ - + if(strlen(hash) != SHA_DIGEST_LENGTH*2) { syslog(LOG_ERR, _("Intruder: wrong challenge reply length from %s (%s)"), cl->name, cl->hostname); return -1; } - + /* Convert the hash to binary format */ - + hex2bin(hash, hash, SHA_DIGEST_LENGTH); - + /* Verify the incoming hash with the calculated hash */ - + if(!memcmp(hash, cl->chal_answer, SHA_DIGEST_LENGTH)) { syslog(LOG_ERR, _("Intruder: wrong challenge reply from %s (%s)"), cl->name, cl->hostname); @@ -358,7 +368,7 @@ cp If we are accepting this new connection, then send our identity, if we are making this connecting, acknowledge. */ - + free(hash); free(cl->chal_answer); @@ -384,14 +394,14 @@ 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 old connection that has timed out but we don't know it yet. */ - while((old = lookup_id(cl->name))) + while((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"), @@ -427,14 +437,58 @@ cp int send_add_subnet(conn_list_t *cl, conn_list_t *other, subnet_t *subnet) { cp -/* return send_request(cl, "%d %s %d %s", ADD_SUBNET, - other->name, subnet->type, net2str(subnet)); */ return send_request(cl, "%d %s %s", ADD_SUBNET, - other->name, net2str(subnet)); + other->name, net2str(subnet)); } int add_subnet_h(conn_list_t *cl) { + char *subnetstr; + char *name; + conn_list_t *owner; + subnet_t *subnet, *old; +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; + } + + /* Check if owner name is a valid */ + + if(!check_id(name)) + { + syslog(LOG_ERR, _("Got bad ADD_SUBNET from %s (%s): invalid identity name"), cl->name, cl->hostname); + return -1; + } + + /* Check if subnet string is valid */ + + if((subnet = str2net(subnetstr)) == -1) + { + syslog(LOG_ERR, _("Got bad ADD_SUBNET from %s (%s): invalid subnet string"), cl->name, cl->hostname); + return -1; + } + + /* Check if somebody tries to add a subnet of ourself */ + + if(!strcmp(name, myself->name)) + { + syslog(LOG_ERR, _("Warning: got ADD_SUBNET from %s (%s) for ourself, restarting"), + cl->name, cl->hostname); + sighup = 1; + return 0; + } + + /* Check if the owner of the new subnet is in the connection list */ + + if(!(owner = lookup_id(name)) + { + syslog(LOG_NOTICE, _("Got ADD_SUBNET for %s from %s (%s) which is not in our connection list"), + name, cl->name, cl->hostname); + } + + } int send_del_subnet(conn_list_t *cl, conn_list_t *other, subnet_t *subnet) @@ -445,6 +499,50 @@ cp int del_subnet_h(conn_list_t *cl) { + char *subnetstr; + char *name; + conn_list_t *owner; + subnet_t *subnet, *old; +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; + } + + /* Check if owner name is a valid */ + + if(!check_id(name)) + { + syslog(LOG_ERR, _("Got bad DEL_SUBNET from %s (%s): invalid identity name"), cl->name, cl->hostname); + return -1; + } + + /* Check if subnet string is valid */ + + if((subnet = str2net(subnetstr)) == -1) + { + syslog(LOG_ERR, _("Got bad DEL_SUBNET from %s (%s): invalid subnet string"), cl->name, cl->hostname); + return -1; + } + + /* Check if somebody tries to delete 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); + sighup = 1; + return 0; + } + + /* Check if the owner of the new subnet is in the connection list */ + + if(!(owner = lookup_id(name)) + { + syslog(LOG_NOTICE, _("Got DEL_SUBNET for %s from %s (%s) which is not in our connection list"), + name, cl->name, cl->hostname); + } } /* New and closed connections notification */ @@ -466,10 +564,10 @@ cp { syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s)"), cl->name, cl->hostname); return -1; - } + } /* Check if option string is valid */ - + if((new->options = str2opt(options)) == -1) { syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s): invalid option string"), cl->name, cl->hostname); @@ -477,15 +575,15 @@ cp } /* Check if identity is a valid name */ - + if(!check_id(new->name)) { syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s): invalid identity name"), cl->name, cl->hostname); return -1; } - + /* Check if somebody tries to add ourself */ - + if(!strcmp(new->name, myself->name)) { syslog(LOG_ERR, _("Warning: got ADD_HOST from %s (%s) for ourself, restarting"), cl->name, cl->hostname); @@ -496,7 +594,7 @@ cp /* Fill in more of the new conn_list structure */ new->hostname = hostlookup(htonl(new->real_ip)); - + /* Check if the new host already exists in the connnection list */ if((old = lookup_id(new->name))) @@ -505,14 +603,14 @@ cp { if(debug_lvl > DEBUG_CONNECTIONS) syslog(LOG_NOTICE, _("Got duplicate ADD_HOST for %s (%s) from %s (%s)"), - old->name, old->hostname, new->name, new->hostname); - return 0; + old->name, old->hostname, new->name, new->hostname); + return 0; } else { if(debug_lvl > DEBUG_CONNECTIONS) syslog(LOG_NOTICE, _("Removing old entry for %s (%s)"), - old->name, old->hostname); + old->name, old->hostname); old->status.active = 0; terminate_connection(old); } @@ -522,15 +620,15 @@ cp new->nexthop = cl; new->status.active = 1; - + /* Hook it up into the conn_list */ conn_list_add(conn_list, new); /* Tell the rest about the new host */ - + notify_others(new, cl, send_add_host); - + cp return 0; } @@ -539,7 +637,7 @@ int send_del_host(conn_list_t *cl, conn_list_t *other) { cp return send_request(cl, "%d %s %lx:%d", DEL_HOST, - other->name, other->real_ip, other->port); + other->name, other->real_ip, other->port); } int del_host_h(conn_list_t *cl) @@ -548,21 +646,21 @@ int del_host_h(conn_list_t *cl) ip_t address; port_t port; conn_list_t *old; - + cp if(sscanf(cl->buffer, "%*d %as %lx:%d", &id, &address, &port) != 3) { syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s)"), - cl->name, cl->hostname); + cl->name, cl->hostname); return -1; - } + } /* Check if somebody tries to delete ourself */ - + if(!strcmp(id, myself->name)) { syslog(LOG_ERR, _("Warning: got DEL_HOST from %s (%s) for ourself, restarting"), - cl->name, cl->hostname); + cl->name, cl->hostname); sighup = 1; return 0; } @@ -587,7 +685,7 @@ cp if(debug_lvl > DEBUG_CONNECTIONS) { syslog(LOG_NOTICE, _("Got DEL_HOST for %s from %s (%s) which is not in our connection list"), - id, cl->name, cl->hostname); + id, cl->name, cl->hostname); } cp return 0; @@ -612,14 +710,14 @@ cp if(sscanf(cl->buffer, "%*d %d %as", &statusno, &statusstring) != 2) { syslog(LOG_ERR, _("Got bad STATUS from %s (%s)"), - cl->name, cl->hostname); + cl->name, cl->hostname); return -1; } if(debug_lvl > DEBUG_STATUS) { syslog(LOG_NOTICE, _("Status message from %s (%s): %s: %s"), - cl->name, cl->hostname, status_text[statusno], statusstring); + cl->name, cl->hostname, status_text[statusno], statusstring); } cp @@ -643,14 +741,14 @@ cp if(sscanf(cl->buffer, "%*d %d %as", &errno, &errorstring) != 2) { syslog(LOG_ERR, _("Got bad error from %s (%s)"), - cl->name, cl->hostname); + cl->name, cl->hostname); return -1; } if(debug_lvl > DEBUG_error) { syslog(LOG_NOTICE, _("Error message from %s (%s): %s: %s"), - cl->name, cl->hostname, strerror(errno), errorstring); + cl->name, cl->hostname, strerror(errno), errorstring); } free(errorstring); @@ -714,7 +812,7 @@ cp { if(p!=cl && p->status.meta && p->status.active) send_request(p, "%d %s", KEY_CHANGED, - from->name); + from->name); } cp return 0; @@ -728,33 +826,33 @@ cp if(sscanf(cl->buffer, "%*d %as", &from_id) != 1) { syslog(LOG_ERR, _("Got bad KEY_CHANGED from %s (%s)"), - cl->name, cl->hostname); + cl->name, cl->hostname); return -1; - } + } if(!(from = lookup_id(from_id))) { syslog(LOG_ERR, _("Got KEY_CHANGED from %s (%s) origin %s which does not exist in our connection list"), - cl->name, cl->hostname, from_id); + cl->name, cl->hostname, from_id); free(from_id); return -1; } free(from_id); - + from->status.validkey = 0; from->status.waitingforkey = 0; - + send_key_changed(from, cl); cp return 0; } - + int send_req_key(conn_list_t *from, conn_list_t *to) { cp return send_request(to->nexthop, "%d %s %s", REQ_KEY, - from->name, to->name); + from->name, to->name); } int req_key_h(conn_list_t *cl) @@ -765,14 +863,14 @@ cp if(sscanf(cl->buffer, "%*d %as %as", &from_id, &to_id) != 2) { syslog(LOG_ERR, _("Got bad REQ_KEY from %s (%s)"), - cl->name, cl->hostname); + cl->name, cl->hostname); return -1; - } + } if(!(from = lookup_id(from_id))) { syslog(LOG_ERR, _("Got REQ_KEY from %s (%s) origin %s which does not exist in our connection list"), - cl->name, cl->hostname, from_id); + cl->name, cl->hostname, from_id); free(from_id); free(to_id); return -1; } @@ -788,7 +886,7 @@ cp if(!(to = lookup_id(to_id))) { syslog(LOG_ERR, _("Got REQ_KEY from %s (%s) destination %s which does not exist in our connection list"), - cl->name, cl->hostname, to_id); + cl->name, cl->hostname, to_id); free(from_id); free(to_id); return -1; } @@ -804,7 +902,7 @@ int send_ans_key(conn_list_t *from, conn_list_t *to, char *datakey) { cp return send_request(to->nexthop, "%d %s %s %s", ANS_KEY, - from->name, to->name, datakey); + from->name, to->name, datakey); } int ans_key_h(conn_list_t *cl) @@ -816,14 +914,14 @@ cp if(sscanf(cl->buffer, "%*d %as %as %as", &from_id, &to_id, &datakey) != 3) { syslog(LOG_ERR, _("Got bad ANS_KEY from %s (%s)"), - cl->name, cl->hostname); + cl->name, cl->hostname); return -1; - } + } if(!(from = lookup_id(from_id))) { syslog(LOG_ERR, _("Got ANS_KEY from %s (%s) origin %s which does not exist in our connection list"), - cl->name, cl->hostname, from_id); + cl->name, cl->hostname, from_id); free(from_id); free(to_id); free(datakey); return -1; } @@ -833,13 +931,13 @@ cp if(!strcmp(to_id, myself->name)) { /* It is for us, convert it to binary and set the key with it. */ - + keylength = strlen(datakey); - + if((keylength%2) || (keylength <= 0)) { syslog(LOG_ERR, _("Got bad ANS_KEY from %s (%s) origin %s: invalid key"), - cl->name, cl->hostname, from->name); + cl->name, cl->hostname, from->name); free(from_id); free(to_id); free(datakey); return -1; } @@ -852,7 +950,7 @@ cp if(!(to = lookup_id(to_id))) { syslog(LOG_ERR, _("Got ANS_KEY from %s (%s) destination %s which does not exist in our connection list"), - cl->name, cl->hostname, to_id); + cl->name, cl->hostname, to_id); free(from_id); free(to_id); free(datakey); return -1; } @@ -873,7 +971,7 @@ cp */ int notify_others(conn_list_t *new, conn_list_t *source, - int (*function)(conn_list_t*, conn_list_t*)) + int (*function)(conn_list_t*, conn_list_t*)) { conn_list_t *p; cp