2 protocol_auth.c -- handle the meta-protocol, authentication
3 Copyright (C) 1999-2003 Ivo Timmermans <ivo@o2w.nl>,
4 2000-2003 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 1.1.4.24 2003/07/17 15:06:26 guus Exp $
25 #include <openssl/sha.h>
26 #include <openssl/rand.h>
27 #include <openssl/evp.h>
31 #include "connection.h"
42 int send_id(connection_t *c)
46 return send_request(c, "%d %s %d", ID, myself->connection->name,
47 myself->connection->protocol_version);
50 int id_h(connection_t *c)
52 char name[MAX_STRING_SIZE];
57 if(sscanf(c->buffer, "%*d " MAX_STRING " %d", name, &c->protocol_version) != 2) {
58 logger(LOG_ERR, _("Got bad %s from %s (%s)"), "ID", c->name,
63 /* Check if identity is a valid name */
66 logger(LOG_ERR, _("Got bad %s from %s (%s): %s"), "ID", c->name,
67 c->hostname, "invalid name");
71 /* If we set c->name in advance, make sure we are connected to the right host */
74 if(strcmp(c->name, name)) {
75 logger(LOG_ERR, _("Peer %s is %s instead of %s"), c->hostname, name,
80 c->name = xstrdup(name);
82 /* Check if version matches */
84 if(c->protocol_version != myself->connection->protocol_version) {
85 logger(LOG_ERR, _("Peer %s (%s) uses incompatible version %d"),
86 c->name, c->hostname, c->protocol_version);
92 init_configuration(&c->config_tree);
93 c->allow_request = ACK;
98 init_configuration(&c->config_tree);
100 bla = read_connection_config(c);
103 logger(LOG_ERR, _("Peer %s had unknown identity (%s)"), c->hostname,
109 if(read_rsa_public_key(c)) {
113 /* Check some options */
115 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &bla) && bla) || myself->options & OPTION_INDIRECT)
116 c->options |= OPTION_INDIRECT;
118 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &bla) && bla) || myself->options & OPTION_TCPONLY)
119 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
121 c->allow_request = METAKEY;
123 return send_metakey(c);
126 int send_metakey(connection_t *c)
128 char buffer[MAX_STRING_SIZE];
133 len = RSA_size(c->rsa_key);
135 /* Allocate buffers for the meta key */
138 c->outkey = xmalloc(len);
141 c->outctx = xmalloc_and_zero(sizeof(*c->outctx));
143 /* Copy random data to the buffer */
145 RAND_bytes(c->outkey, len);
147 /* The message we send must be smaller than the modulus of the RSA key.
148 By definition, for a key of k bits, the following formula holds:
150 2^(k-1) <= modulus < 2^(k)
152 Where ^ means "to the power of", not "xor".
153 This means that to be sure, we must choose our message < 2^(k-1).
154 This can be done by setting the most significant bit to zero.
157 c->outkey[0] &= 0x7F;
159 ifdebug(SCARY_THINGS) {
160 bin2hex(c->outkey, buffer, len);
161 buffer[len * 2] = '\0';
162 logger(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"),
166 /* Encrypt the random data
168 We do not use one of the PKCS padding schemes here.
169 This is allowed, because we encrypt a totally random string
170 with a length equal to that of the modulus of the RSA key.
173 if(RSA_public_encrypt(len, c->outkey, buffer, c->rsa_key, RSA_NO_PADDING) != len) {
174 logger(LOG_ERR, _("Error during encryption of meta key for %s (%s)"),
175 c->name, c->hostname);
179 /* Convert the encrypted random data to a hexadecimal formatted string */
181 bin2hex(buffer, buffer, len);
182 buffer[len * 2] = '\0';
184 /* Send the meta key */
186 x = send_request(c, "%d %d %d %d %d %s", METAKEY,
187 c->outcipher ? c->outcipher->nid : 0,
188 c->outdigest ? c->outdigest->type : 0, c->outmaclength,
189 c->outcompression, buffer);
191 /* Further outgoing requests are encrypted with the key we just generated */
194 EVP_EncryptInit(c->outctx, c->outcipher,
195 c->outkey + len - c->outcipher->key_len,
196 c->outkey + len - c->outcipher->key_len -
197 c->outcipher->iv_len);
199 c->status.encryptout = 1;
205 int metakey_h(connection_t *c)
207 char buffer[MAX_STRING_SIZE];
208 int cipher, digest, maclength, compression;
213 if(sscanf(c->buffer, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, buffer) != 5) {
214 logger(LOG_ERR, _("Got bad %s from %s (%s)"), "METAKEY", c->name,
219 len = RSA_size(myself->connection->rsa_key);
221 /* Check if the length of the meta key is all right */
223 if(strlen(buffer) != len * 2) {
224 logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong keylength");
228 /* Allocate buffers for the meta key */
231 c->inkey = xmalloc(len);
234 c->inctx = xmalloc_and_zero(sizeof(*c->inctx));
236 /* Convert the challenge from hexadecimal back to binary */
238 hex2bin(buffer, buffer, len);
240 /* Decrypt the meta key */
242 if(RSA_private_decrypt(len, buffer, c->inkey, myself->connection->rsa_key, RSA_NO_PADDING) != len) { /* See challenge() */
243 logger(LOG_ERR, _("Error during encryption of meta key for %s (%s)"),
244 c->name, c->hostname);
248 ifdebug(SCARY_THINGS) {
249 bin2hex(c->inkey, buffer, len);
250 buffer[len * 2] = '\0';
251 logger(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
254 /* All incoming requests will now be encrypted. */
256 /* Check and lookup cipher and digest algorithms */
259 c->incipher = EVP_get_cipherbynid(cipher);
262 logger(LOG_ERR, _("%s (%s) uses unknown cipher!"), c->name, c->hostname);
266 EVP_DecryptInit(c->inctx, c->incipher,
267 c->inkey + len - c->incipher->key_len,
268 c->inkey + len - c->incipher->key_len -
269 c->incipher->iv_len);
271 c->status.decryptin = 1;
276 c->inmaclength = maclength;
279 c->indigest = EVP_get_digestbynid(digest);
282 logger(LOG_ERR, _("Node %s (%s) uses unknown digest!"), c->name, c->hostname);
286 if(c->inmaclength > c->indigest->md_size || c->inmaclength < 0) {
287 logger(LOG_ERR, _("%s (%s) uses bogus MAC length!"), c->name, c->hostname);
294 c->incompression = compression;
296 c->allow_request = CHALLENGE;
298 return send_challenge(c);
301 int send_challenge(connection_t *c)
303 char buffer[MAX_STRING_SIZE];
308 /* CHECKME: what is most reasonable value for len? */
310 len = RSA_size(c->rsa_key);
312 /* Allocate buffers for the challenge */
315 c->hischallenge = xmalloc(len);
317 /* Copy random data to the buffer */
319 RAND_bytes(c->hischallenge, len);
323 bin2hex(c->hischallenge, buffer, len);
324 buffer[len * 2] = '\0';
326 /* Send the challenge */
328 x = send_request(c, "%d %s", CHALLENGE, buffer);
333 int challenge_h(connection_t *c)
335 char buffer[MAX_STRING_SIZE];
340 if(sscanf(c->buffer, "%*d " MAX_STRING, buffer) != 1) {
341 logger(LOG_ERR, _("Got bad %s from %s (%s)"), "CHALLENGE", c->name,
346 len = RSA_size(myself->connection->rsa_key);
348 /* Check if the length of the challenge is all right */
350 if(strlen(buffer) != len * 2) {
351 logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name,
352 c->hostname, "wrong challenge length");
356 /* Allocate buffers for the challenge */
359 c->mychallenge = xmalloc(len);
361 /* Convert the challenge from hexadecimal back to binary */
363 hex2bin(buffer, c->mychallenge, len);
365 c->allow_request = CHAL_REPLY;
367 /* Rest is done by send_chal_reply() */
369 return send_chal_reply(c);
372 int send_chal_reply(connection_t *c)
374 char hash[EVP_MAX_MD_SIZE * 2 + 1];
379 /* Calculate the hash from the challenge we received */
381 EVP_DigestInit(&ctx, c->indigest);
382 EVP_DigestUpdate(&ctx, c->mychallenge,
383 RSA_size(myself->connection->rsa_key));
384 EVP_DigestFinal(&ctx, hash, NULL);
386 /* Convert the hash to a hexadecimal formatted string */
388 bin2hex(hash, hash, c->indigest->md_size);
389 hash[c->indigest->md_size * 2] = '\0';
393 return send_request(c, "%d %s", CHAL_REPLY, hash);
396 int chal_reply_h(connection_t *c)
398 char hishash[MAX_STRING_SIZE];
399 char myhash[EVP_MAX_MD_SIZE];
404 if(sscanf(c->buffer, "%*d " MAX_STRING, hishash) != 1) {
405 logger(LOG_ERR, _("Got bad %s from %s (%s)"), "CHAL_REPLY", c->name,
410 /* Check if the length of the hash is all right */
412 if(strlen(hishash) != c->outdigest->md_size * 2) {
413 logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name,
414 c->hostname, _("wrong challenge reply length"));
418 /* Convert the hash to binary format */
420 hex2bin(hishash, hishash, c->outdigest->md_size);
422 /* Calculate the hash from the challenge we sent */
424 EVP_DigestInit(&ctx, c->outdigest);
425 EVP_DigestUpdate(&ctx, c->hischallenge, RSA_size(c->rsa_key));
426 EVP_DigestFinal(&ctx, myhash, NULL);
428 /* Verify the incoming hash with the calculated hash */
430 if(memcmp(hishash, myhash, c->outdigest->md_size)) {
431 logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name,
432 c->hostname, _("wrong challenge reply"));
434 ifdebug(SCARY_THINGS) {
435 bin2hex(myhash, hishash, SHA_DIGEST_LENGTH);
436 hishash[SHA_DIGEST_LENGTH * 2] = '\0';
437 logger(LOG_DEBUG, _("Expected challenge reply: %s"), hishash);
443 /* Identity has now been positively verified.
444 Send an acknowledgement with the rest of the information needed.
447 c->allow_request = ACK;
452 int send_ack(connection_t *c)
454 /* ACK message contains rest of the information the other end needs
455 to create node_t and edge_t structures. */
462 /* Estimate weight */
464 gettimeofday(&now, NULL);
465 c->estimated_weight =
466 (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec -
467 c->start.tv_usec) / 1000;
468 x = send_request(c, "%d %s %d %lx", ACK, myport, c->estimated_weight,
474 static void send_everything(connection_t *c)
476 avl_node_t *node, *node2;
481 /* Send all known subnets and edges */
483 for(node = node_tree->head; node; node = node->next) {
484 n = (node_t *) node->data;
486 for(node2 = n->subnet_tree->head; node2; node2 = node2->next) {
487 s = (subnet_t *) node2->data;
488 send_add_subnet(c, s);
491 for(node2 = n->edge_tree->head; node2; node2 = node2->next) {
492 e = (edge_t *) node2->data;
498 int ack_h(connection_t *c)
500 char hisport[MAX_STRING_SIZE];
501 char *hisaddress, *dummy;
508 if(sscanf(c->buffer, "%*d " MAX_STRING " %d %lx", hisport, &weight, &options) != 3) {
509 logger(LOG_ERR, _("Got bad %s from %s (%s)"), "ACK", c->name,
514 /* Check if we already have a node_t for him */
516 n = lookup_node(c->name);
520 n->name = xstrdup(c->name);
524 /* Oh dear, we already have a connection to this node. */
525 ifdebug(CONNECTIONS) logger(LOG_DEBUG, _("Established a second connection with %s (%s), closing old connection"),
526 n->name, n->hostname);
527 terminate_connection(n->connection, 0);
528 /* Run graph algorithm to purge key and make sure up/down scripts are rerun with new IP addresses and stuff */
535 c->options |= options;
537 /* Activate this connection */
539 c->allow_request = ALL;
540 c->status.active = 1;
542 ifdebug(CONNECTIONS) logger(LOG_NOTICE, _("Connection with %s (%s) activated"), c->name,
545 /* Send him everything we know */
549 /* Create an edge_t for this connection */
551 c->edge = new_edge();
553 c->edge->from = myself;
555 sockaddr2str(&c->address, &hisaddress, &dummy);
556 c->edge->address = str2sockaddr(hisaddress, hisport);
559 c->edge->weight = (weight + c->estimated_weight) / 2;
560 c->edge->connection = c;
561 c->edge->options = c->options;
565 /* Notify everyone of the new edge */
567 send_add_edge(broadcast, c->edge);
569 /* Run MST and SSSP algorithms */