- if(request_handlers[request](cl))
- /* Something went wrong. Probably scriptkiddies. Terminate. */
- {
- syslog(LOG_ERR, _("Error while processing %s from %s (%s)"),
- request_name[request], cl->name, cl->hostname);
- return -1;
- }
- }
- else
- {
- syslog(LOG_ERR, _("Bogus data received from %s (%s)"),
- cl->name, cl->hostname);
- return -1;
- }
-}
-
-/* Connection protocol:
-
- Client Server
- send_id(u)
- send_challenge(R)
- 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,
- (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.
-*/
-
-int send_id(conn_list_t *cl)
-{
-cp
- cl->allow_request = CHALLENGE;
-cp
- return send_request(cl, "%d %s %d %lx %hd", ID, myself->name, myself->protocol_version, myself->options, myself->port);
-}
-
-int id_h(conn_list_t *cl)
-{
- conn_list_t *old;
- config_t *cfg;
-cp
- if(sscanf(cl->buffer, "%*d %as %d %lx %hd", &cl->name, &cl->protocol_version, &cl->options, &cl->port) != 4)
- {
- 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);
- 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 */
-cp
- if(read_host_config(cl))
- {
- syslog(LOG_ERR, _("Peer %s had unknown identity (%s)"), cl->hostname, cl->name);
- 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.
- */
-cp
- 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;
- }
- }
-cp
- if(!(cfg = get_config_val(cl->config, publickey)))
- {
- syslog(LOG_ERR, _("No public key known for %s (%s)"), cl->name, cl->hostname);
- return -1;
- }
- else
- {
-cp
- cl->rsa_key = RSA_new();
- BN_hex2bn(&cl->rsa_key->n, cfg->data.ptr);
- BN_hex2bn(&cl->rsa_key->e, "FFFF");
- }
-
-cp
- return send_challenge(cl);
-}
-
-int send_challenge(conn_list_t *cl)
-{
- char *buffer;
- int len, x;
-cp
- len = RSA_size(cl->rsa_key);
-
- /* Allocate buffers for the challenge */
-
- buffer = xmalloc(len*2+1);
-
- if(cl->hischallenge)
- free(cl->hischallenge);
-
- cl->hischallenge = xmalloc(len);
-cp
- /* Seed the PRNG with urandom (can't afford to block) */
-
- RAND_load_file("/dev/urandom", 1024);
-
- /* Copy random data to the buffer */
-
- RAND_bytes(cl->hischallenge, len);
-
- cl->hischallenge[0] &= 0x7F; /* Somehow if the first byte is more than 0xD0 or something like that, decryption fails... */
-
- if(debug_lvl >= DEBUG_SCARY_THINGS)
- {
- bin2hex(cl->hischallenge, buffer, len);
- buffer[len*2] = '\0';
- syslog(LOG_DEBUG, _("Generated random challenge (unencrypted): %s"), buffer);
- }
-
- /* Encrypt the random data */
-
- if(RSA_public_encrypt(len, cl->hischallenge, buffer, cl->rsa_key, RSA_NO_PADDING) != len) /* NO_PADDING because the message size equals the RSA key size and it is totally random */
- {
- syslog(LOG_ERR, _("Error during encryption of challenge for %s (%s)"), cl->name, cl->hostname);
- free(buffer);
- return -1;
- }
-cp
- /* Convert the encrypted random data to a hexadecimal formatted string */
-
- bin2hex(buffer, buffer, len);
- buffer[len*2] = '\0';
-
- /* Send the challenge */
-
- cl->allow_request = CHAL_REPLY;
- x = send_request(cl, "%d %s", CHALLENGE, buffer);
- free(buffer);
-cp
- return x;
-}
-
-int challenge_h(conn_list_t *cl)
-{
- char *buffer;
- int len;
-cp
- if(sscanf(cl->buffer, "%*d %as", &buffer) != 1)
- {
- syslog(LOG_ERR, _("Got bad CHALLENGE from %s (%s)"), cl->name, cl->hostname);
- return -1;
- }
-
- len = RSA_size(myself->rsa_key);
-
- /* Check if the length of the challenge is all right */
-
- if(strlen(buffer) != len*2)
- {
- syslog(LOG_ERR, _("Intruder: wrong challenge length from %s (%s)"), cl->name, cl->hostname);
- free(buffer);
- return -1;
- }
-
- /* Allocate buffers for the challenge */
-
- if(!cl->mychallenge)
- cl->mychallenge = xmalloc(len);
-
- /* Convert the challenge from hexadecimal back to binary */
-
- hex2bin(buffer,buffer,len);
-
- /* Decrypt the challenge */
-
- if(RSA_private_decrypt(len, buffer, cl->mychallenge, myself->rsa_key, RSA_NO_PADDING) != len) /* See challenge() */
- {
- syslog(LOG_ERR, _("Error during encryption of challenge for %s (%s)"), cl->name, cl->hostname);
- free(buffer);
- return -1;
- }
-
- if(debug_lvl >= DEBUG_SCARY_THINGS)
- {
- bin2hex(cl->mychallenge, buffer, len);
- buffer[len*2] = '\0';
- syslog(LOG_DEBUG, _("Received random challenge (unencrypted): %s"), buffer);
- }
-
- free(buffer);
-
- /* Rest is done by send_chal_reply() */
-cp
- return send_chal_reply(cl);
-}
-
-int send_chal_reply(conn_list_t *cl)
-{
- char hash[SHA_DIGEST_LENGTH*2+1];
-cp
- if(!cl->mychallenge)
- {
- 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 */
-
- SHA1(cl->mychallenge, RSA_size(myself->rsa_key), hash);
-
- /* Convert the hash to a hexadecimal formatted string */
-
- bin2hex(hash,hash,SHA_DIGEST_LENGTH);
- hash[SHA_DIGEST_LENGTH*2] = '\0';
-
- /* Send the reply */
-
- if(cl->status.outgoing)
- cl->allow_request = ID;
- else
- cl->allow_request = ACK;
-
-cp
- return send_request(cl, "%d %s", CHAL_REPLY, hash);
-}
-
-int chal_reply_h(conn_list_t *cl)
-{
- char *hishash;
- char myhash[SHA_DIGEST_LENGTH];
-cp
- if(sscanf(cl->buffer, "%*d %as", &hishash) != 1)
- {
- syslog(LOG_ERR, _("Got bad CHAL_REPLY from %s (%s)"), cl->name, cl->hostname);
- free(hishash);
- return -1;
- }
-
- /* Check if the length of the hash is all right */
-
- if(strlen(hishash) != SHA_DIGEST_LENGTH*2)
- {
- syslog(LOG_ERR, _("Intruder: wrong challenge reply length from %s (%s)"), cl->name, cl->hostname);
- free(hishash);
- return -1;
- }
-
- /* Convert the hash to binary format */
-
- hex2bin(hishash, hishash, SHA_DIGEST_LENGTH);
-
- /* Calculate the hash from the challenge we sent */
-
- SHA1(cl->hischallenge, RSA_size(cl->rsa_key), myhash);
-
- /* Verify the incoming hash with the calculated hash */
-
- if(memcmp(hishash, myhash, SHA_DIGEST_LENGTH))
- {
- syslog(LOG_ERR, _("Intruder: wrong challenge reply from %s (%s)"), cl->name, cl->hostname);
- if(debug_lvl >= DEBUG_SCARY_THINGS)
- {
- bin2hex(myhash, hishash, SHA_DIGEST_LENGTH);
- hishash[SHA_DIGEST_LENGTH*2] = '\0';
- syslog(LOG_DEBUG, _("Expected challenge reply: %s"), hishash);
- }
- 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.
- */
-cp
- if(cl->status.outgoing)
- return send_ack(cl);
- else
- return send_id(cl);
-}
-
-int send_ack(conn_list_t *cl)
-{
-cp
- cl->allow_request = ACK;
-cp
- return send_request(cl, "%d", ACK);
-}
-
-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 name. 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)))
- {
- 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);
- old->status.active = 0;
- terminate_connection(old);
- }
-
- /* Activate this connection */
-
- cl->allow_request = ALL;
- cl->status.active = 1;
-
- if(debug_lvl >= DEBUG_CONNECTIONS)
- syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), cl->name, cl->hostname);
-
- /* Exchange information about other tinc daemons */
-
-/* FIXME: reprogram this.
- notify_others(cl, NULL, send_add_host);
- notify_one(cl);
-*/
-
-cp
- if(cl->status.outgoing)
- return 0;
- else
- return send_ack(cl);
-}
-
-/* Address and subnet information exchange */
-
-int send_add_subnet(conn_list_t *cl, conn_list_t *other, subnet_t *subnet)
-{
- int x;
- char *netstr;
-cp
- 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)
-{
- 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);
- free(name); free(subnetstr);
- 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);
- free(name); free(subnetstr);
- return -1;
- }
-
- /* Check if subnet string is valid */
-
- if(!(subnet = str2net(subnetstr)))
- {
- 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 */
-
- if(!strcmp(name, myself->name))
- {
- syslog(LOG_ERR, _("Warning: got ADD_SUBNET from %s (%s) for ourself, restarting"),
- cl->name, cl->hostname);
- free(name);
- sighup = 1;
- return 0;
- }
-
- /* Check if the owner of the new subnet is in the connection list */
-
- if(!(owner = lookup_id(name)))
- {
- 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 */