2 protocol_auth.c -- handle the meta-protocol, authentication
3 Copyright (C) 1999-2002 Ivo Timmermans <itimmermans@bigfoot.com>,
4 2000-2002 Guus Sliepen <guus@sliepen.warande.net>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 $Id: protocol_auth.c,v 1.2 2002/05/02 11:50:07 zarq Exp $
35 #include <openssl/sha.h>
36 #include <openssl/rand.h>
37 #include <openssl/evp.h>
39 #ifndef HAVE_RAND_PSEUDO_BYTES
40 #define RAND_pseudo_bytes RAND_bytes
44 #include "interface.h"
49 #include "connection.h"
57 int send_id(connection_t *c)
60 return send_request(c, "%d %s %d", ID, myself->connection->name, myself->connection->protocol_version);
63 int id_h(connection_t *c)
65 char name[MAX_STRING_SIZE];
68 if(sscanf(c->buffer, "%*d "MAX_STRING" %d", name, &c->protocol_version) != 2)
70 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ID", c->name, c->hostname);
74 /* Check if identity is a valid name */
78 syslog(LOG_ERR, _("Got bad %s from %s (%s): %s"), "ID", c->name, c->hostname, "invalid name");
82 /* If we set c->name in advance, make sure we are connected to the right host */
86 if(strcmp(c->name, name))
88 syslog(LOG_ERR, _("Peer %s is %s instead of %s"), c->hostname, name, c->name);
93 c->name = xstrdup(name);
95 /* Check if version matches */
97 if(c->protocol_version != myself->connection->protocol_version)
99 syslog(LOG_ERR, _("Peer %s (%s) uses incompatible version %d"),
100 c->name, c->hostname, c->protocol_version);
107 init_configuration(&c->config_tree);
108 c->allow_request = ACK;
114 init_configuration(&c->config_tree);
116 if((bla = read_connection_config(c)))
118 syslog(LOG_ERR, _("Peer %s had unknown identity (%s)"), c->hostname, c->name);
123 if(read_rsa_public_key(c))
128 /* Check some options */
130 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &bla) && bla) || myself->options & OPTION_INDIRECT)
131 c->options |= OPTION_INDIRECT;
133 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &bla) && bla) || myself->options & OPTION_TCPONLY)
134 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
136 c->allow_request = METAKEY;
138 return send_metakey(c);
141 int send_metakey(connection_t *c)
143 char buffer[MAX_STRING_SIZE];
146 len = RSA_size(c->rsa_key);
148 /* Allocate buffers for the meta key */
151 c->outkey = xmalloc(len);
154 c->outctx = xmalloc(sizeof(*c->outctx));
156 /* Copy random data to the buffer */
158 RAND_bytes(c->outkey, len);
160 /* The message we send must be smaller than the modulus of the RSA key.
161 By definition, for a key of k bits, the following formula holds:
163 2^(k-1) <= modulus < 2^(k)
165 Where ^ means "to the power of", not "xor".
166 This means that to be sure, we must choose our message < 2^(k-1).
167 This can be done by setting the most significant bit to zero.
170 c->outkey[0] &= 0x7F;
172 if(debug_lvl >= DEBUG_SCARY_THINGS)
174 bin2hex(c->outkey, buffer, len);
175 buffer[len*2] = '\0';
176 syslog(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"), buffer);
179 /* Encrypt the random data
181 We do not use one of the PKCS padding schemes here.
182 This is allowed, because we encrypt a totally random string
183 with a length equal to that of the modulus of the RSA key.
186 if(RSA_public_encrypt(len, c->outkey, buffer, c->rsa_key, RSA_NO_PADDING) != len)
188 syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
192 /* Convert the encrypted random data to a hexadecimal formatted string */
194 bin2hex(buffer, buffer, len);
195 buffer[len*2] = '\0';
197 /* Send the meta key */
199 x = send_request(c, "%d %d %d %d %d %s", METAKEY,
200 c->outcipher?c->outcipher->nid:0, c->outdigest?c->outdigest->type:0,
201 c->outmaclength, c->outcompression, buffer);
203 /* Further outgoing requests are encrypted with the key we just generated */
207 EVP_EncryptInit(c->outctx, c->outcipher,
208 c->outkey + len - c->outcipher->key_len,
209 c->outkey + len - c->outcipher->key_len - c->outcipher->iv_len);
211 c->status.encryptout = 1;
217 int metakey_h(connection_t *c)
219 char buffer[MAX_STRING_SIZE];
220 int cipher, digest, maclength, compression;
223 if(sscanf(c->buffer, "%*d %d %d %d %d "MAX_STRING, &cipher, &digest, &maclength, &compression, buffer) != 5)
225 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "METAKEY", c->name, c->hostname);
229 len = RSA_size(myself->connection->rsa_key);
231 /* Check if the length of the meta key is all right */
233 if(strlen(buffer) != len*2)
235 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong keylength");
239 /* Allocate buffers for the meta key */
242 c->inkey = xmalloc(len);
245 c->inctx = xmalloc(sizeof(*c->inctx));
247 /* Convert the challenge from hexadecimal back to binary */
249 hex2bin(buffer,buffer,len);
251 /* Decrypt the meta key */
253 if(RSA_private_decrypt(len, buffer, c->inkey, myself->connection->rsa_key, RSA_NO_PADDING) != len) /* See challenge() */
255 syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
259 if(debug_lvl >= DEBUG_SCARY_THINGS)
261 bin2hex(c->inkey, buffer, len);
262 buffer[len*2] = '\0';
263 syslog(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
266 /* All incoming requests will now be encrypted. */
268 /* Check and lookup cipher and digest algorithms */
272 c->incipher = EVP_get_cipherbynid(cipher);
275 syslog(LOG_ERR, _("%s (%s) uses unknown cipher!"), c->name, c->hostname);
279 EVP_DecryptInit(c->inctx, c->incipher,
280 c->inkey + len - c->incipher->key_len,
281 c->inkey + len - c->incipher->key_len - c->incipher->iv_len);
283 c->status.decryptin = 1;
290 c->inmaclength = maclength;
294 c->indigest = EVP_get_digestbynid(digest);
297 syslog(LOG_ERR, _("Node %s (%s) uses unknown digest!"), c->name, c->hostname);
301 if(c->inmaclength > c->indigest->md_size || c->inmaclength < 0)
303 syslog(LOG_ERR, _("%s (%s) uses bogus MAC length!"), c->name, c->hostname);
312 c->incompression = compression;
314 c->allow_request = CHALLENGE;
316 return send_challenge(c);
319 int send_challenge(connection_t *c)
321 char buffer[MAX_STRING_SIZE];
324 /* CHECKME: what is most reasonable value for len? */
326 len = RSA_size(c->rsa_key);
328 /* Allocate buffers for the challenge */
331 c->hischallenge = xmalloc(len);
333 /* Copy random data to the buffer */
335 RAND_bytes(c->hischallenge, len);
340 bin2hex(c->hischallenge, buffer, len);
341 buffer[len*2] = '\0';
344 /* Send the challenge */
346 x = send_request(c, "%d %s", CHALLENGE, buffer);
351 int challenge_h(connection_t *c)
353 char buffer[MAX_STRING_SIZE];
356 if(sscanf(c->buffer, "%*d "MAX_STRING, buffer) != 1)
358 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHALLENGE", c->name, c->hostname);
362 len = RSA_size(myself->connection->rsa_key);
364 /* Check if the length of the challenge is all right */
366 if(strlen(buffer) != len*2)
368 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong challenge length");
372 /* Allocate buffers for the challenge */
375 c->mychallenge = xmalloc(len);
377 /* Convert the challenge from hexadecimal back to binary */
379 hex2bin(buffer,c->mychallenge,len);
381 c->allow_request = CHAL_REPLY;
383 /* Rest is done by send_chal_reply() */
385 return send_chal_reply(c);
388 int send_chal_reply(connection_t *c)
390 char hash[EVP_MAX_MD_SIZE*2+1];
393 /* Calculate the hash from the challenge we received */
395 EVP_DigestInit(&ctx, c->indigest);
396 EVP_DigestUpdate(&ctx, c->mychallenge, RSA_size(myself->connection->rsa_key));
397 EVP_DigestFinal(&ctx, hash, NULL);
399 /* Convert the hash to a hexadecimal formatted string */
401 bin2hex(hash,hash,c->indigest->md_size);
402 hash[c->indigest->md_size*2] = '\0';
407 return send_request(c, "%d %s", CHAL_REPLY, hash);
410 int chal_reply_h(connection_t *c)
412 char hishash[MAX_STRING_SIZE];
413 char myhash[EVP_MAX_MD_SIZE];
416 if(sscanf(c->buffer, "%*d "MAX_STRING, hishash) != 1)
418 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHAL_REPLY", c->name, c->hostname);
422 /* Check if the length of the hash is all right */
424 if(strlen(hishash) != c->outdigest->md_size*2)
426 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply length"));
430 /* Convert the hash to binary format */
432 hex2bin(hishash, hishash, c->outdigest->md_size);
434 /* Calculate the hash from the challenge we sent */
436 EVP_DigestInit(&ctx, c->outdigest);
437 EVP_DigestUpdate(&ctx, c->hischallenge, RSA_size(c->rsa_key));
438 EVP_DigestFinal(&ctx, myhash, NULL);
440 /* Verify the incoming hash with the calculated hash */
442 if(memcmp(hishash, myhash, c->outdigest->md_size))
444 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply"));
445 if(debug_lvl >= DEBUG_SCARY_THINGS)
447 bin2hex(myhash, hishash, SHA_DIGEST_LENGTH);
448 hishash[SHA_DIGEST_LENGTH*2] = '\0';
449 syslog(LOG_DEBUG, _("Expected challenge reply: %s"), hishash);
454 /* Identity has now been positively verified.
455 Send an acknowledgement with the rest of the information needed.
458 c->allow_request = ACK;
463 int send_ack(connection_t *c)
465 /* ACK message contains rest of the information the other end needs
466 to create node_t and edge_t structures. */
469 char *address, *port;
472 /* Estimate weight */
474 gettimeofday(&now, NULL);
475 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
476 sockaddr2str(&c->address, &address, &port);
477 x = send_request(c, "%d %s %s %d %lx", ACK, myport, address, c->estimated_weight, c->options);
484 void send_everything(connection_t *c)
486 avl_node_t *node, *node2;
491 /* Send all known subnets */
493 for(node = node_tree->head; node; node = node->next)
495 n = (node_t *)node->data;
497 for(node2 = n->subnet_tree->head; node2; node2 = node2->next)
499 s = (subnet_t *)node2->data;
500 send_add_subnet(c, s);
504 /* Send all known edges */
506 for(node = edge_tree->head; node; node = node->next)
508 e = (edge_t *)node->data;
517 int ack_h(connection_t *c)
519 char myaddress[MAX_STRING_SIZE];
520 char hisport[MAX_STRING_SIZE];
521 char *hisaddress, *dummy;
528 if(sscanf(c->buffer, "%*d "MAX_STRING" "MAX_STRING" %d %lx", hisport, myaddress, &weight, &options) != 4)
530 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ACK", c->name, c->hostname);
534 /* Check if we already have a node_t for him */
536 n = lookup_node(c->name);
541 n->name = xstrdup(c->name);
548 /* Oh dear, we already have a connection to this node. */
549 log(DEBUG_CONNECTIONS, TLOG_DEBUG,
550 _("Established a second connection with %s (%s), closing old connection"),
551 n->name, n->hostname);
552 terminate_connection(n->connection, 0);
555 /* FIXME: check if information in existing node matches that of the other end of this connection */
560 c->options |= options;
562 /* Create an edge_t for this connection */
564 c->edge = new_edge();
566 c->edge->from.node = myself;
567 /* c->edge->from.tcpaddress = str2sockaddr(address, port);*/
568 c->edge->from.udpaddress = str2sockaddr(myaddress, myport);
569 c->edge->to.node = n;
570 /* c->edge->to.tcpaddress = c->address; */
571 sockaddr2str(&c->address, &hisaddress, &dummy);
572 c->edge->to.udpaddress = str2sockaddr(hisaddress, hisport);
575 c->edge->weight = (weight + c->estimated_weight) / 2;
576 c->edge->connection = c;
577 c->edge->options = c->options;
581 /* Activate this connection */
583 c->allow_request = ALL;
584 c->status.active = 1;
586 if(debug_lvl >= DEBUG_CONNECTIONS)
587 syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), c->name, c->hostname);
590 /* Send him everything we know */
594 /* Notify others of this connection */
596 for(node = connection_tree->head; node; node = node->next)
598 other = (connection_t *)node->data;
600 if(other->status.active && other != c)
601 send_add_edge(other, c->edge);
604 /* Run MST and SSSP algorithms */