2 protocol_auth.c -- handle the meta-protocol, authentication
3 Copyright (C) 1999-2002 Ivo Timmermans <ivo@o2w.nl>,
4 2000-2002 Guus Sliepen <guus@sliepen.eu.org>
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 1.1.4.10 2002/09/03 20:43:25 guus Exp $
36 #include <openssl/sha.h>
37 #include <openssl/rand.h>
38 #include <openssl/evp.h>
40 #ifndef HAVE_RAND_PSEUDO_BYTES
41 #define RAND_pseudo_bytes RAND_bytes
49 #include "connection.h"
54 int send_id(connection_t *c)
57 return send_request(c, "%d %s %d", ID, myself->connection->name, myself->connection->protocol_version);
60 int id_h(connection_t *c)
62 char name[MAX_STRING_SIZE];
65 if(sscanf(c->buffer, "%*d "MAX_STRING" %d", name, &c->protocol_version) != 2)
67 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ID", c->name, c->hostname);
71 /* Check if identity is a valid name */
75 syslog(LOG_ERR, _("Got bad %s from %s (%s): %s"), "ID", c->name, c->hostname, "invalid name");
79 /* If we set c->name in advance, make sure we are connected to the right host */
83 if(strcmp(c->name, name))
85 syslog(LOG_ERR, _("Peer %s is %s instead of %s"), c->hostname, name, c->name);
90 c->name = xstrdup(name);
92 /* Check if version matches */
94 if(c->protocol_version != myself->connection->protocol_version)
96 syslog(LOG_ERR, _("Peer %s (%s) uses incompatible version %d"),
97 c->name, c->hostname, c->protocol_version);
104 init_configuration(&c->config_tree);
105 c->allow_request = ACK;
111 init_configuration(&c->config_tree);
113 if((bla = read_connection_config(c)))
115 syslog(LOG_ERR, _("Peer %s had unknown identity (%s)"), c->hostname, c->name);
120 if(read_rsa_public_key(c))
125 /* Check some options */
127 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &bla) && bla) || myself->options & OPTION_INDIRECT)
128 c->options |= OPTION_INDIRECT;
130 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &bla) && bla) || myself->options & OPTION_TCPONLY)
131 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
133 c->allow_request = METAKEY;
135 return send_metakey(c);
138 int send_metakey(connection_t *c)
140 char buffer[MAX_STRING_SIZE];
143 len = RSA_size(c->rsa_key);
145 /* Allocate buffers for the meta key */
148 c->outkey = xmalloc(len);
151 c->outctx = xmalloc(sizeof(*c->outctx));
153 /* Copy random data to the buffer */
155 RAND_bytes(c->outkey, len);
157 /* The message we send must be smaller than the modulus of the RSA key.
158 By definition, for a key of k bits, the following formula holds:
160 2^(k-1) <= modulus < 2^(k)
162 Where ^ means "to the power of", not "xor".
163 This means that to be sure, we must choose our message < 2^(k-1).
164 This can be done by setting the most significant bit to zero.
167 c->outkey[0] &= 0x7F;
169 if(debug_lvl >= DEBUG_SCARY_THINGS)
171 bin2hex(c->outkey, buffer, len);
172 buffer[len*2] = '\0';
173 syslog(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"), buffer);
176 /* Encrypt the random data
178 We do not use one of the PKCS padding schemes here.
179 This is allowed, because we encrypt a totally random string
180 with a length equal to that of the modulus of the RSA key.
183 if(RSA_public_encrypt(len, c->outkey, buffer, c->rsa_key, RSA_NO_PADDING) != len)
185 syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
189 /* Convert the encrypted random data to a hexadecimal formatted string */
191 bin2hex(buffer, buffer, len);
192 buffer[len*2] = '\0';
194 /* Send the meta key */
196 x = send_request(c, "%d %d %d %d %d %s", METAKEY,
197 c->outcipher?c->outcipher->nid:0, c->outdigest?c->outdigest->type:0,
198 c->outmaclength, c->outcompression, buffer);
200 /* Further outgoing requests are encrypted with the key we just generated */
204 EVP_EncryptInit(c->outctx, c->outcipher,
205 c->outkey + len - c->outcipher->key_len,
206 c->outkey + len - c->outcipher->key_len - c->outcipher->iv_len);
208 c->status.encryptout = 1;
214 int metakey_h(connection_t *c)
216 char buffer[MAX_STRING_SIZE];
217 int cipher, digest, maclength, compression;
220 if(sscanf(c->buffer, "%*d %d %d %d %d "MAX_STRING, &cipher, &digest, &maclength, &compression, buffer) != 5)
222 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "METAKEY", c->name, c->hostname);
226 len = RSA_size(myself->connection->rsa_key);
228 /* Check if the length of the meta key is all right */
230 if(strlen(buffer) != len*2)
232 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong keylength");
236 /* Allocate buffers for the meta key */
239 c->inkey = xmalloc(len);
242 c->inctx = xmalloc(sizeof(*c->inctx));
244 /* Convert the challenge from hexadecimal back to binary */
246 hex2bin(buffer,buffer,len);
248 /* Decrypt the meta key */
250 if(RSA_private_decrypt(len, buffer, c->inkey, myself->connection->rsa_key, RSA_NO_PADDING) != len) /* See challenge() */
252 syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
256 if(debug_lvl >= DEBUG_SCARY_THINGS)
258 bin2hex(c->inkey, buffer, len);
259 buffer[len*2] = '\0';
260 syslog(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
263 /* All incoming requests will now be encrypted. */
265 /* Check and lookup cipher and digest algorithms */
269 c->incipher = EVP_get_cipherbynid(cipher);
272 syslog(LOG_ERR, _("%s (%s) uses unknown cipher!"), c->name, c->hostname);
276 EVP_DecryptInit(c->inctx, c->incipher,
277 c->inkey + len - c->incipher->key_len,
278 c->inkey + len - c->incipher->key_len - c->incipher->iv_len);
280 c->status.decryptin = 1;
287 c->inmaclength = maclength;
291 c->indigest = EVP_get_digestbynid(digest);
294 syslog(LOG_ERR, _("Node %s (%s) uses unknown digest!"), c->name, c->hostname);
298 if(c->inmaclength > c->indigest->md_size || c->inmaclength < 0)
300 syslog(LOG_ERR, _("%s (%s) uses bogus MAC length!"), c->name, c->hostname);
309 c->incompression = compression;
311 c->allow_request = CHALLENGE;
313 return send_challenge(c);
316 int send_challenge(connection_t *c)
318 char buffer[MAX_STRING_SIZE];
321 /* CHECKME: what is most reasonable value for len? */
323 len = RSA_size(c->rsa_key);
325 /* Allocate buffers for the challenge */
328 c->hischallenge = xmalloc(len);
330 /* Copy random data to the buffer */
332 RAND_bytes(c->hischallenge, len);
337 bin2hex(c->hischallenge, buffer, len);
338 buffer[len*2] = '\0';
341 /* Send the challenge */
343 x = send_request(c, "%d %s", CHALLENGE, buffer);
348 int challenge_h(connection_t *c)
350 char buffer[MAX_STRING_SIZE];
353 if(sscanf(c->buffer, "%*d "MAX_STRING, buffer) != 1)
355 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHALLENGE", c->name, c->hostname);
359 len = RSA_size(myself->connection->rsa_key);
361 /* Check if the length of the challenge is all right */
363 if(strlen(buffer) != len*2)
365 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong challenge length");
369 /* Allocate buffers for the challenge */
372 c->mychallenge = xmalloc(len);
374 /* Convert the challenge from hexadecimal back to binary */
376 hex2bin(buffer,c->mychallenge,len);
378 c->allow_request = CHAL_REPLY;
380 /* Rest is done by send_chal_reply() */
382 return send_chal_reply(c);
385 int send_chal_reply(connection_t *c)
387 char hash[EVP_MAX_MD_SIZE*2+1];
390 /* Calculate the hash from the challenge we received */
392 EVP_DigestInit(&ctx, c->indigest);
393 EVP_DigestUpdate(&ctx, c->mychallenge, RSA_size(myself->connection->rsa_key));
394 EVP_DigestFinal(&ctx, hash, NULL);
396 /* Convert the hash to a hexadecimal formatted string */
398 bin2hex(hash,hash,c->indigest->md_size);
399 hash[c->indigest->md_size*2] = '\0';
404 return send_request(c, "%d %s", CHAL_REPLY, hash);
407 int chal_reply_h(connection_t *c)
409 char hishash[MAX_STRING_SIZE];
410 char myhash[EVP_MAX_MD_SIZE];
413 if(sscanf(c->buffer, "%*d "MAX_STRING, hishash) != 1)
415 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHAL_REPLY", c->name, c->hostname);
419 /* Check if the length of the hash is all right */
421 if(strlen(hishash) != c->outdigest->md_size*2)
423 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply length"));
427 /* Convert the hash to binary format */
429 hex2bin(hishash, hishash, c->outdigest->md_size);
431 /* Calculate the hash from the challenge we sent */
433 EVP_DigestInit(&ctx, c->outdigest);
434 EVP_DigestUpdate(&ctx, c->hischallenge, RSA_size(c->rsa_key));
435 EVP_DigestFinal(&ctx, myhash, NULL);
437 /* Verify the incoming hash with the calculated hash */
439 if(memcmp(hishash, myhash, c->outdigest->md_size))
441 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply"));
442 if(debug_lvl >= DEBUG_SCARY_THINGS)
444 bin2hex(myhash, hishash, SHA_DIGEST_LENGTH);
445 hishash[SHA_DIGEST_LENGTH*2] = '\0';
446 syslog(LOG_DEBUG, _("Expected challenge reply: %s"), hishash);
451 /* Identity has now been positively verified.
452 Send an acknowledgement with the rest of the information needed.
455 c->allow_request = ACK;
460 int send_ack(connection_t *c)
462 /* ACK message contains rest of the information the other end needs
463 to create node_t structures. */
466 char *address, *port;
469 /* Estimate weight */
471 gettimeofday(&now, NULL);
472 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
473 sockaddr2str(&c->address, &address, &port);
474 x = send_request(c, "%d %s %s %lx", ACK, myport, address, c->options);
481 void send_everything(connection_t *c)
483 avl_node_t *node, *node2;
488 /* Send all known nodes and subnets */
490 for(node = node_tree->head; node; node = node->next)
492 n = (node_t *)node->data;
494 if(n != c->node && n != myself)
497 for(node2 = n->subnet_tree->head; node2; node2 = node2->next)
499 s = (subnet_t *)node2->data;
500 send_add_subnet(c, s);
504 /* Inform others of this new node */
506 for(node = connection_tree->head; node; node = node->next)
508 other = (connection_t *)node->data;
510 if(other->status.active && other != c)
511 send_add_node(other, c->node);
515 int ack_h(connection_t *c)
517 char myaddress[MAX_STRING_SIZE];
518 char hisport[MAX_STRING_SIZE];
519 char *hisaddress, *dummy;
524 if(sscanf(c->buffer, "%*d "MAX_STRING" "MAX_STRING" %lx", hisport, myaddress, &options) != 3)
526 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ACK", c->name, c->hostname);
530 /* Check if we already have a node_t for him */
532 n = lookup_node(c->name);
537 n->name = xstrdup(c->name);
544 /* Oh dear, we already have a connection to this node. */
545 if(debug_lvl >= DEBUG_CONNECTIONS)
546 syslog(LOG_DEBUG, _("Established a second connection with %s (%s), closing old connection"), n->name, n->hostname);
547 terminate_connection(n->connection, 0);
552 c->options |= options;
553 c->myaddress = str2sockaddr(myaddress, myport);
556 sockaddr2str(&c->address, &hisaddress, &dummy);
557 node = avl_unlink(node_udp_tree, n);
558 n->address = str2sockaddr(hisaddress, hisport);
559 avl_insert_node(node_udp_tree, node);
562 n->hostname = sockaddr2hostname(&n->address);
563 n->options = c->options;
565 n->via = n->nexthop = n;
566 n->status.reachable = 1;
567 n->status.validkey = 0;
568 n->status.waitingforkey = 0;
570 /* Activate this connection */
572 c->allow_request = ALL;
573 c->status.active = 1;
575 if(debug_lvl >= DEBUG_CONNECTIONS)
576 syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), c->name, c->hostname);
579 /* Send him everything we know and tell the others about him */