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 1.1.4.15 2002/09/09 19:39:59 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"
56 int send_id(connection_t *c)
59 return send_request(c, "%d %s %d", ID, myself->connection->name, myself->connection->protocol_version);
62 int id_h(connection_t *c)
64 char name[MAX_STRING_SIZE];
67 if(sscanf(c->buffer, "%*d "MAX_STRING" %d", name, &c->protocol_version) != 2)
69 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ID", c->name, c->hostname);
73 /* Check if identity is a valid name */
77 syslog(LOG_ERR, _("Got bad %s from %s (%s): %s"), "ID", c->name, c->hostname, "invalid name");
81 /* If we set c->name in advance, make sure we are connected to the right host */
85 if(strcmp(c->name, name))
87 syslog(LOG_ERR, _("Peer %s is %s instead of %s"), c->hostname, name, c->name);
92 c->name = xstrdup(name);
94 /* Check if version matches */
96 if(c->protocol_version != myself->connection->protocol_version)
98 syslog(LOG_ERR, _("Peer %s (%s) uses incompatible version %d"),
99 c->name, c->hostname, c->protocol_version);
106 init_configuration(&c->config_tree);
107 c->allow_request = ACK;
113 init_configuration(&c->config_tree);
115 bla = read_connection_config(c);
119 syslog(LOG_ERR, _("Peer %s had unknown identity (%s)"), c->hostname, c->name);
124 if(read_rsa_public_key(c))
129 /* Check some options */
131 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &bla) && bla) || myself->options & OPTION_INDIRECT)
132 c->options |= OPTION_INDIRECT;
134 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &bla) && bla) || myself->options & OPTION_TCPONLY)
135 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
137 c->allow_request = METAKEY;
139 return send_metakey(c);
142 int send_metakey(connection_t *c)
144 char buffer[MAX_STRING_SIZE];
147 len = RSA_size(c->rsa_key);
149 /* Allocate buffers for the meta key */
152 c->outkey = xmalloc(len);
155 c->outctx = xmalloc(sizeof(*c->outctx));
157 /* Copy random data to the buffer */
159 RAND_bytes(c->outkey, len);
161 /* The message we send must be smaller than the modulus of the RSA key.
162 By definition, for a key of k bits, the following formula holds:
164 2^(k-1) <= modulus < 2^(k)
166 Where ^ means "to the power of", not "xor".
167 This means that to be sure, we must choose our message < 2^(k-1).
168 This can be done by setting the most significant bit to zero.
171 c->outkey[0] &= 0x7F;
173 if(debug_lvl >= DEBUG_SCARY_THINGS)
175 bin2hex(c->outkey, buffer, len);
176 buffer[len*2] = '\0';
177 syslog(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"), buffer);
180 /* Encrypt the random data
182 We do not use one of the PKCS padding schemes here.
183 This is allowed, because we encrypt a totally random string
184 with a length equal to that of the modulus of the RSA key.
187 if(RSA_public_encrypt(len, c->outkey, buffer, c->rsa_key, RSA_NO_PADDING) != len)
189 syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
193 /* Convert the encrypted random data to a hexadecimal formatted string */
195 bin2hex(buffer, buffer, len);
196 buffer[len*2] = '\0';
198 /* Send the meta key */
200 x = send_request(c, "%d %d %d %d %d %s", METAKEY,
201 c->outcipher?c->outcipher->nid:0, c->outdigest?c->outdigest->type:0,
202 c->outmaclength, c->outcompression, buffer);
204 /* Further outgoing requests are encrypted with the key we just generated */
208 EVP_EncryptInit(c->outctx, c->outcipher,
209 c->outkey + len - c->outcipher->key_len,
210 c->outkey + len - c->outcipher->key_len - c->outcipher->iv_len);
212 c->status.encryptout = 1;
218 int metakey_h(connection_t *c)
220 char buffer[MAX_STRING_SIZE];
221 int cipher, digest, maclength, compression;
224 if(sscanf(c->buffer, "%*d %d %d %d %d "MAX_STRING, &cipher, &digest, &maclength, &compression, buffer) != 5)
226 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "METAKEY", c->name, c->hostname);
230 len = RSA_size(myself->connection->rsa_key);
232 /* Check if the length of the meta key is all right */
234 if(strlen(buffer) != len*2)
236 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong keylength");
240 /* Allocate buffers for the meta key */
243 c->inkey = xmalloc(len);
246 c->inctx = xmalloc(sizeof(*c->inctx));
248 /* Convert the challenge from hexadecimal back to binary */
250 hex2bin(buffer,buffer,len);
252 /* Decrypt the meta key */
254 if(RSA_private_decrypt(len, buffer, c->inkey, myself->connection->rsa_key, RSA_NO_PADDING) != len) /* See challenge() */
256 syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
260 if(debug_lvl >= DEBUG_SCARY_THINGS)
262 bin2hex(c->inkey, buffer, len);
263 buffer[len*2] = '\0';
264 syslog(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
267 /* All incoming requests will now be encrypted. */
269 /* Check and lookup cipher and digest algorithms */
273 c->incipher = EVP_get_cipherbynid(cipher);
276 syslog(LOG_ERR, _("%s (%s) uses unknown cipher!"), c->name, c->hostname);
280 EVP_DecryptInit(c->inctx, c->incipher,
281 c->inkey + len - c->incipher->key_len,
282 c->inkey + len - c->incipher->key_len - c->incipher->iv_len);
284 c->status.decryptin = 1;
291 c->inmaclength = maclength;
295 c->indigest = EVP_get_digestbynid(digest);
298 syslog(LOG_ERR, _("Node %s (%s) uses unknown digest!"), c->name, c->hostname);
302 if(c->inmaclength > c->indigest->md_size || c->inmaclength < 0)
304 syslog(LOG_ERR, _("%s (%s) uses bogus MAC length!"), c->name, c->hostname);
313 c->incompression = compression;
315 c->allow_request = CHALLENGE;
317 return send_challenge(c);
320 int send_challenge(connection_t *c)
322 char buffer[MAX_STRING_SIZE];
325 /* CHECKME: what is most reasonable value for len? */
327 len = RSA_size(c->rsa_key);
329 /* Allocate buffers for the challenge */
332 c->hischallenge = xmalloc(len);
334 /* Copy random data to the buffer */
336 RAND_bytes(c->hischallenge, len);
341 bin2hex(c->hischallenge, buffer, len);
342 buffer[len*2] = '\0';
345 /* Send the challenge */
347 x = send_request(c, "%d %s", CHALLENGE, buffer);
352 int challenge_h(connection_t *c)
354 char buffer[MAX_STRING_SIZE];
357 if(sscanf(c->buffer, "%*d "MAX_STRING, buffer) != 1)
359 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHALLENGE", c->name, c->hostname);
363 len = RSA_size(myself->connection->rsa_key);
365 /* Check if the length of the challenge is all right */
367 if(strlen(buffer) != len*2)
369 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong challenge length");
373 /* Allocate buffers for the challenge */
376 c->mychallenge = xmalloc(len);
378 /* Convert the challenge from hexadecimal back to binary */
380 hex2bin(buffer,c->mychallenge,len);
382 c->allow_request = CHAL_REPLY;
384 /* Rest is done by send_chal_reply() */
386 return send_chal_reply(c);
389 int send_chal_reply(connection_t *c)
391 char hash[EVP_MAX_MD_SIZE*2+1];
394 /* Calculate the hash from the challenge we received */
396 EVP_DigestInit(&ctx, c->indigest);
397 EVP_DigestUpdate(&ctx, c->mychallenge, RSA_size(myself->connection->rsa_key));
398 EVP_DigestFinal(&ctx, hash, NULL);
400 /* Convert the hash to a hexadecimal formatted string */
402 bin2hex(hash,hash,c->indigest->md_size);
403 hash[c->indigest->md_size*2] = '\0';
408 return send_request(c, "%d %s", CHAL_REPLY, hash);
411 int chal_reply_h(connection_t *c)
413 char hishash[MAX_STRING_SIZE];
414 char myhash[EVP_MAX_MD_SIZE];
417 if(sscanf(c->buffer, "%*d "MAX_STRING, hishash) != 1)
419 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHAL_REPLY", c->name, c->hostname);
423 /* Check if the length of the hash is all right */
425 if(strlen(hishash) != c->outdigest->md_size*2)
427 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply length"));
431 /* Convert the hash to binary format */
433 hex2bin(hishash, hishash, c->outdigest->md_size);
435 /* Calculate the hash from the challenge we sent */
437 EVP_DigestInit(&ctx, c->outdigest);
438 EVP_DigestUpdate(&ctx, c->hischallenge, RSA_size(c->rsa_key));
439 EVP_DigestFinal(&ctx, myhash, NULL);
441 /* Verify the incoming hash with the calculated hash */
443 if(memcmp(hishash, myhash, c->outdigest->md_size))
445 syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply"));
446 if(debug_lvl >= DEBUG_SCARY_THINGS)
448 bin2hex(myhash, hishash, SHA_DIGEST_LENGTH);
449 hishash[SHA_DIGEST_LENGTH*2] = '\0';
450 syslog(LOG_DEBUG, _("Expected challenge reply: %s"), hishash);
455 /* Identity has now been positively verified.
456 Send an acknowledgement with the rest of the information needed.
459 c->allow_request = ACK;
464 int send_ack(connection_t *c)
466 /* ACK message contains rest of the information the other end needs
467 to create node_t and edge_t structures. */
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 x = send_request(c, "%d %s %d %lx", ACK, myport, c->estimated_weight, c->options);
481 void send_everything(connection_t *c)
483 avl_node_t *node, *node2;
488 /* Send all known subnets and edges */
490 for(node = node_tree->head; node; node = node->next)
492 n = (node_t *)node->data;
494 for(node2 = n->subnet_tree->head; node2; node2 = node2->next)
496 s = (subnet_t *)node2->data;
497 send_add_subnet(c, s);
500 for(node2 = n->edge_tree->head; node2; node2 = node2->next)
502 e = (edge_t *)node2->data;
508 int ack_h(connection_t *c)
510 char hisport[MAX_STRING_SIZE];
511 char *hisaddress, *dummy;
516 if(sscanf(c->buffer, "%*d "MAX_STRING" %d %lx", hisport, &weight, &options) != 3)
518 syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ACK", c->name, c->hostname);
522 /* Check if we already have a node_t for him */
524 n = lookup_node(c->name);
529 n->name = xstrdup(c->name);
536 /* Oh dear, we already have a connection to this node. */
537 if(debug_lvl >= DEBUG_CONNECTIONS)
538 syslog(LOG_DEBUG, _("Established a second connection with %s (%s), closing old connection"), n->name, n->hostname);
539 terminate_connection(n->connection, 0);
545 c->options |= options;
547 /* Activate this connection */
549 c->allow_request = ALL;
550 c->status.active = 1;
552 if(debug_lvl >= DEBUG_CONNECTIONS)
553 syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), c->name, c->hostname);
555 /* Send him everything we know */
559 /* Create an edge_t for this connection */
561 c->edge = new_edge();
563 c->edge->from = myself;
565 sockaddr2str(&c->address, &hisaddress, &dummy);
566 c->edge->address = str2sockaddr(hisaddress, hisport);
569 c->edge->weight = (weight + c->estimated_weight) / 2;
570 c->edge->connection = c;
571 c->edge->options = c->options;
576 /* Notify everyone of the new edge */
578 send_add_edge(broadcast, c->edge);
580 /* Run MST and SSSP algorithms */