X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fpokey%2Fprotocol_auth.c;fp=src%2Fpokey%2Fprotocol_auth.c;h=f45a4634cade540ddb7f577f89050260b68b59a5;hp=0000000000000000000000000000000000000000;hb=04d33be4bd102de67bb6dba5c449e12fea0db4d2;hpb=b0a676988a8da3120e64ef0e1a4ea4c28b1511e1 diff --git a/src/pokey/protocol_auth.c b/src/pokey/protocol_auth.c new file mode 100644 index 00000000..f45a4634 --- /dev/null +++ b/src/pokey/protocol_auth.c @@ -0,0 +1,609 @@ +/* + protocol_auth.c -- handle the meta-protocol, authentication + Copyright (C) 1999-2002 Ivo Timmermans , + 2000-2002 Guus Sliepen + + 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 +#include +#include +#include +#include + +#include +#include +#include + +#include +#include +#include + +#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; +}