+/*
+ protocol_auth.c -- handle the meta-protocol, authentication
+ Copyright (C) 1999-2002 Ivo Timmermans <itimmermans@bigfoot.com>,
+ 2000-2002 Guus Sliepen <guus@sliepen.warande.net>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ $Id: protocol_auth.c,v 1.1 2002/04/28 12:46:26 zarq Exp $
+*/
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <errno.h>
+
+#include <utils.h>
+#include <xalloc.h>
+#include <avl_tree.h>
+
+#include <openssl/sha.h>
+#include <openssl/rand.h>
+#include <openssl/evp.h>
+
+#ifndef HAVE_RAND_PSEUDO_BYTES
+#define RAND_pseudo_bytes RAND_bytes
+#endif
+
+#include "conf.h"
+#include "interface.h"
+#include "net.h"
+#include "netutl.h"
+#include "protocol.h"
+#include "meta.h"
+#include "connection.h"
+#include "node.h"
+#include "edge.h"
+#include "graph.h"
+#include "logging.h"
+
+#include "system.h"
+
+int send_id(connection_t *c)
+{
+cp
+ return send_request(c, "%d %s %d", ID, myself->connection->name, myself->connection->protocol_version);
+}
+
+int id_h(connection_t *c)
+{
+ char name[MAX_STRING_SIZE];
+ int bla;
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING" %d", name, &c->protocol_version) != 2)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ID", c->name, c->hostname);
+ return -1;
+ }
+
+ /* Check if identity is a valid name */
+
+ if(check_id(name))
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s): %s"), "ID", c->name, c->hostname, "invalid name");
+ return -1;
+ }
+
+ /* If we set c->name in advance, make sure we are connected to the right host */
+
+ if(c->name)
+ {
+ if(strcmp(c->name, name))
+ {
+ syslog(LOG_ERR, _("Peer %s is %s instead of %s"), c->hostname, name, c->name);
+ return -1;
+ }
+ }
+ else
+ c->name = xstrdup(name);
+
+ /* Check if version matches */
+
+ if(c->protocol_version != myself->connection->protocol_version)
+ {
+ syslog(LOG_ERR, _("Peer %s (%s) uses incompatible version %d"),
+ c->name, c->hostname, c->protocol_version);
+ return -1;
+ }
+
+ if(bypass_security)
+ {
+ if(!c->config_tree)
+ init_configuration(&c->config_tree);
+ c->allow_request = ACK;
+ return send_ack(c);
+ }
+
+ if(!c->config_tree)
+ {
+ init_configuration(&c->config_tree);
+
+ if((bla = read_connection_config(c)))
+ {
+ syslog(LOG_ERR, _("Peer %s had unknown identity (%s)"), c->hostname, c->name);
+ return -1;
+ }
+ }
+
+ if(read_rsa_public_key(c))
+ {
+ return -1;
+ }
+
+ /* Check some options */
+
+ if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &bla) && bla) || myself->options & OPTION_INDIRECT)
+ c->options |= OPTION_INDIRECT;
+
+ if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &bla) && bla) || myself->options & OPTION_TCPONLY)
+ c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
+
+ c->allow_request = METAKEY;
+cp
+ return send_metakey(c);
+}
+
+int send_metakey(connection_t *c)
+{
+ char buffer[MAX_STRING_SIZE];
+ int len, x;
+cp
+ len = RSA_size(c->rsa_key);
+
+ /* Allocate buffers for the meta key */
+
+ if(!c->outkey)
+ c->outkey = xmalloc(len);
+
+ if(!c->outctx)
+ c->outctx = xmalloc(sizeof(*c->outctx));
+cp
+ /* Copy random data to the buffer */
+
+ RAND_bytes(c->outkey, len);
+
+ /* The message we send must be smaller than the modulus of the RSA key.
+ By definition, for a key of k bits, the following formula holds:
+
+ 2^(k-1) <= modulus < 2^(k)
+
+ Where ^ means "to the power of", not "xor".
+ This means that to be sure, we must choose our message < 2^(k-1).
+ This can be done by setting the most significant bit to zero.
+ */
+
+ c->outkey[0] &= 0x7F;
+
+ if(debug_lvl >= DEBUG_SCARY_THINGS)
+ {
+ bin2hex(c->outkey, buffer, len);
+ buffer[len*2] = '\0';
+ syslog(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"), buffer);
+ }
+
+ /* Encrypt the random data
+
+ We do not use one of the PKCS padding schemes here.
+ This is allowed, because we encrypt a totally random string
+ with a length equal to that of the modulus of the RSA key.
+ */
+
+ if(RSA_public_encrypt(len, c->outkey, buffer, c->rsa_key, RSA_NO_PADDING) != len)
+ {
+ syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
+ return -1;
+ }
+cp
+ /* Convert the encrypted random data to a hexadecimal formatted string */
+
+ bin2hex(buffer, buffer, len);
+ buffer[len*2] = '\0';
+
+ /* Send the meta key */
+
+ x = send_request(c, "%d %d %d %d %d %s", METAKEY,
+ c->outcipher?c->outcipher->nid:0, c->outdigest?c->outdigest->type:0,
+ c->outmaclength, c->outcompression, buffer);
+
+ /* Further outgoing requests are encrypted with the key we just generated */
+
+ if(c->outcipher)
+ {
+ EVP_EncryptInit(c->outctx, c->outcipher,
+ c->outkey + len - c->outcipher->key_len,
+ c->outkey + len - c->outcipher->key_len - c->outcipher->iv_len);
+
+ c->status.encryptout = 1;
+ }
+cp
+ return x;
+}
+
+int metakey_h(connection_t *c)
+{
+ char buffer[MAX_STRING_SIZE];
+ int cipher, digest, maclength, compression;
+ int len;
+cp
+ if(sscanf(c->buffer, "%*d %d %d %d %d "MAX_STRING, &cipher, &digest, &maclength, &compression, buffer) != 5)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "METAKEY", c->name, c->hostname);
+ return -1;
+ }
+cp
+ len = RSA_size(myself->connection->rsa_key);
+
+ /* Check if the length of the meta key is all right */
+
+ if(strlen(buffer) != len*2)
+ {
+ syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong keylength");
+ return -1;
+ }
+
+ /* Allocate buffers for the meta key */
+cp
+ if(!c->inkey)
+ c->inkey = xmalloc(len);
+
+ if(!c->inctx)
+ c->inctx = xmalloc(sizeof(*c->inctx));
+
+ /* Convert the challenge from hexadecimal back to binary */
+cp
+ hex2bin(buffer,buffer,len);
+
+ /* Decrypt the meta key */
+cp
+ if(RSA_private_decrypt(len, buffer, c->inkey, myself->connection->rsa_key, RSA_NO_PADDING) != len) /* See challenge() */
+ {
+ syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
+ return -1;
+ }
+
+ if(debug_lvl >= DEBUG_SCARY_THINGS)
+ {
+ bin2hex(c->inkey, buffer, len);
+ buffer[len*2] = '\0';
+ syslog(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
+ }
+
+ /* All incoming requests will now be encrypted. */
+cp
+ /* Check and lookup cipher and digest algorithms */
+
+ if(cipher)
+ {
+ c->incipher = EVP_get_cipherbynid(cipher);
+ if(!c->incipher)
+ {
+ syslog(LOG_ERR, _("%s (%s) uses unknown cipher!"), c->name, c->hostname);
+ return -1;
+ }
+
+ EVP_DecryptInit(c->inctx, c->incipher,
+ c->inkey + len - c->incipher->key_len,
+ c->inkey + len - c->incipher->key_len - c->incipher->iv_len);
+
+ c->status.decryptin = 1;
+ }
+ else
+ {
+ c->incipher = NULL;
+ }
+
+ c->inmaclength = maclength;
+
+ if(digest)
+ {
+ c->indigest = EVP_get_digestbynid(digest);
+ if(!c->indigest)
+ {
+ syslog(LOG_ERR, _("Node %s (%s) uses unknown digest!"), c->name, c->hostname);
+ return -1;
+ }
+
+ if(c->inmaclength > c->indigest->md_size || c->inmaclength < 0)
+ {
+ syslog(LOG_ERR, _("%s (%s) uses bogus MAC length!"), c->name, c->hostname);
+ return -1;
+ }
+ }
+ else
+ {
+ c->indigest = NULL;
+ }
+
+ c->incompression = compression;
+
+ c->allow_request = CHALLENGE;
+cp
+ return send_challenge(c);
+}
+
+int send_challenge(connection_t *c)
+{
+ char buffer[MAX_STRING_SIZE];
+ int len, x;
+cp
+ /* CHECKME: what is most reasonable value for len? */
+
+ len = RSA_size(c->rsa_key);
+
+ /* Allocate buffers for the challenge */
+
+ if(!c->hischallenge)
+ c->hischallenge = xmalloc(len);
+cp
+ /* Copy random data to the buffer */
+
+ RAND_bytes(c->hischallenge, len);
+
+cp
+ /* Convert to hex */
+
+ bin2hex(c->hischallenge, buffer, len);
+ buffer[len*2] = '\0';
+
+cp
+ /* Send the challenge */
+
+ x = send_request(c, "%d %s", CHALLENGE, buffer);
+cp
+ return x;
+}
+
+int challenge_h(connection_t *c)
+{
+ char buffer[MAX_STRING_SIZE];
+ int len;
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING, buffer) != 1)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHALLENGE", c->name, c->hostname);
+ return -1;
+ }
+
+ len = RSA_size(myself->connection->rsa_key);
+
+ /* Check if the length of the challenge is all right */
+
+ if(strlen(buffer) != len*2)
+ {
+ syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong challenge length");
+ return -1;
+ }
+
+ /* Allocate buffers for the challenge */
+
+ if(!c->mychallenge)
+ c->mychallenge = xmalloc(len);
+
+ /* Convert the challenge from hexadecimal back to binary */
+
+ hex2bin(buffer,c->mychallenge,len);
+
+ c->allow_request = CHAL_REPLY;
+
+ /* Rest is done by send_chal_reply() */
+cp
+ return send_chal_reply(c);
+}
+
+int send_chal_reply(connection_t *c)
+{
+ char hash[EVP_MAX_MD_SIZE*2+1];
+ EVP_MD_CTX ctx;
+cp
+ /* Calculate the hash from the challenge we received */
+
+ EVP_DigestInit(&ctx, c->indigest);
+ EVP_DigestUpdate(&ctx, c->mychallenge, RSA_size(myself->connection->rsa_key));
+ EVP_DigestFinal(&ctx, hash, NULL);
+
+ /* Convert the hash to a hexadecimal formatted string */
+
+ bin2hex(hash,hash,c->indigest->md_size);
+ hash[c->indigest->md_size*2] = '\0';
+
+ /* Send the reply */
+
+cp
+ return send_request(c, "%d %s", CHAL_REPLY, hash);
+}
+
+int chal_reply_h(connection_t *c)
+{
+ char hishash[MAX_STRING_SIZE];
+ char myhash[EVP_MAX_MD_SIZE];
+ EVP_MD_CTX ctx;
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING, hishash) != 1)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "CHAL_REPLY", c->name, c->hostname);
+ return -1;
+ }
+
+ /* Check if the length of the hash is all right */
+
+ if(strlen(hishash) != c->outdigest->md_size*2)
+ {
+ syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply length"));
+ return -1;
+ }
+
+ /* Convert the hash to binary format */
+
+ hex2bin(hishash, hishash, c->outdigest->md_size);
+
+ /* Calculate the hash from the challenge we sent */
+
+ EVP_DigestInit(&ctx, c->outdigest);
+ EVP_DigestUpdate(&ctx, c->hischallenge, RSA_size(c->rsa_key));
+ EVP_DigestFinal(&ctx, myhash, NULL);
+
+ /* Verify the incoming hash with the calculated hash */
+
+ if(memcmp(hishash, myhash, c->outdigest->md_size))
+ {
+ syslog(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply"));
+ 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);
+ }
+ return -1;
+ }
+
+ /* Identity has now been positively verified.
+ Send an acknowledgement with the rest of the information needed.
+ */
+
+ c->allow_request = ACK;
+cp
+ return send_ack(c);
+}
+
+int send_ack(connection_t *c)
+{
+ /* ACK message contains rest of the information the other end needs
+ to create node_t and edge_t structures. */
+
+ int x;
+ char *address, *port;
+ struct timeval now;
+cp
+ /* Estimate weight */
+
+ gettimeofday(&now, NULL);
+ c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
+ sockaddr2str(&c->address, &address, &port);
+ x = send_request(c, "%d %s %s %d %lx", ACK, myport, address, c->estimated_weight, c->options);
+ free(address);
+ free(port);
+cp
+ return x;
+}
+
+void send_everything(connection_t *c)
+{
+ avl_node_t *node, *node2;
+ node_t *n;
+ subnet_t *s;
+ edge_t *e;
+
+ /* Send all known subnets */
+
+ for(node = node_tree->head; node; node = node->next)
+ {
+ n = (node_t *)node->data;
+
+ for(node2 = n->subnet_tree->head; node2; node2 = node2->next)
+ {
+ s = (subnet_t *)node2->data;
+ send_add_subnet(c, s);
+ }
+ }
+
+ /* Send all known edges */
+
+ for(node = edge_tree->head; node; node = node->next)
+ {
+ e = (edge_t *)node->data;
+
+ if(e == c->edge)
+ continue;
+
+ send_add_edge(c, e);
+ }
+}
+
+int ack_h(connection_t *c)
+{
+ char myaddress[MAX_STRING_SIZE];
+ char hisport[MAX_STRING_SIZE];
+ char *hisaddress, *dummy;
+ int weight;
+ long int options;
+ node_t *n;
+ connection_t *other;
+ avl_node_t *node;
+cp
+ if(sscanf(c->buffer, "%*d "MAX_STRING" "MAX_STRING" %d %lx", hisport, myaddress, &weight, &options) != 4)
+ {
+ syslog(LOG_ERR, _("Got bad %s from %s (%s)"), "ACK", c->name, c->hostname);
+ return -1;
+ }
+
+ /* Check if we already have a node_t for him */
+
+ n = lookup_node(c->name);
+
+ if(!n)
+ {
+ n = new_node();
+ n->name = xstrdup(c->name);
+ node_add(n);
+ }
+ else
+ {
+ if(n->connection)
+ {
+ /* Oh dear, we already have a connection to this node. */
+ log(DEBUG_CONNECTIONS, TLOG_DEBUG,
+ _("Established a second connection with %s (%s), closing old connection"),
+ n->name, n->hostname);
+ terminate_connection(n->connection, 0);
+ }
+
+ /* FIXME: check if information in existing node matches that of the other end of this connection */
+ }
+
+ n->connection = c;
+ c->node = n;
+ c->options |= options;
+
+ /* Create an edge_t for this connection */
+
+ c->edge = new_edge();
+cp
+ c->edge->from.node = myself;
+// c->edge->from.tcpaddress = str2sockaddr(address, port);
+ c->edge->from.udpaddress = str2sockaddr(myaddress, myport);
+ c->edge->to.node = n;
+// c->edge->to.tcpaddress = c->address;
+ sockaddr2str(&c->address, &hisaddress, &dummy);
+ c->edge->to.udpaddress = str2sockaddr(hisaddress, hisport);
+ free(hisaddress);
+ free(dummy);
+ c->edge->weight = (weight + c->estimated_weight) / 2;
+ c->edge->connection = c;
+ c->edge->options = c->options;
+cp
+ edge_add(c->edge);
+
+ /* Activate this connection */
+
+ c->allow_request = ALL;
+ c->status.active = 1;
+
+ if(debug_lvl >= DEBUG_CONNECTIONS)
+ syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), c->name, c->hostname);
+
+cp
+ /* Send him everything we know */
+
+ send_everything(c);
+
+ /* Notify others of this connection */
+
+ for(node = connection_tree->head; node; node = node->next)
+ {
+ other = (connection_t *)node->data;
+
+ if(other->status.active && other != c)
+ send_add_edge(other, c->edge);
+ }
+
+ /* Run MST and SSSP algorithms */
+
+ graph();
+cp
+ return 0;
+}
projects / oweals / tinc.git / commitdiff