1 |
/* |
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* ircd-hybrid: an advanced Internet Relay Chat Daemon(ircd). |
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* m_cryptlink.c: Used to negotiate an encrypted link. |
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* |
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* Copyright (C) 2002 by the past and present ircd coders, and others. |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; either version 2 of the License, or |
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* (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 |
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* USA |
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* |
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* $Id$ |
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*/ |
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|
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/* |
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* CRYPTLINK protocol. |
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* |
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* Please see doc/cryptlink.txt for a description of this protocol. |
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* |
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*/ |
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|
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#include "stdinc.h" |
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#include "handlers.h" |
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#include "client.h" /* client struct */ |
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#include "ircd.h" /* me */ |
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#include "modules.h" |
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#include "numeric.h" /* ERR_xxx */ |
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#include "send.h" /* sendto_one */ |
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#include <openssl/rsa.h> /* rsa.h is implicit when building this */ |
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#include "rsa.h" |
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#include "msg.h" |
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#include "parse.h" |
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#include "irc_string.h" /* strncpy_irc */ |
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#include "tools.h" |
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#include "memory.h" |
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#include "common.h" /* TRUE bleah */ |
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#include "event.h" |
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#include "hash.h" /* add_to_client_hash_table */ |
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#include "list.h" /* make_server */ |
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#include "s_conf.h" /* struct AccessItem */ |
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#include "s_log.h" /* log level defines */ |
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#include "s_serv.h" /* server_estab, check_server, my_name_for_link */ |
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#include "s_stats.h" /* ServerStats */ |
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#include "motd.h" |
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|
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static int bogus_host(char *host); |
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static char *parse_cryptserv_args(struct Client *client_p, |
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char *parv[], int parc, char *info, |
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char *key); |
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|
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static void mr_cryptlink(struct Client *, struct Client *, int, char **); |
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static void cryptlink_serv(struct Client *, struct Client *, int, char **); |
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static void cryptlink_auth(struct Client *, struct Client *, int, char **); |
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|
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struct Message cryptlink_msgtab = { |
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"CRYPTLINK", 0, 0, 4, 0, MFLG_SLOW | MFLG_UNREG, 0, |
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{mr_cryptlink, m_ignore, m_error, m_ignore, m_ignore, m_ignore} |
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}; |
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|
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struct CryptLinkStruct |
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{ |
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const char *cmd; /* CRYPTLINK <command> to match */ |
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void (*handler)(); /* Function to call */ |
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}; |
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|
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static struct CryptLinkStruct cryptlink_cmd_table[] = |
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{ |
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/* command function */ |
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{ "AUTH", cryptlink_auth, }, |
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{ "SERV", cryptlink_serv, }, |
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/* End of table */ |
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{ (char *)0, (void (*)())0, } |
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}; |
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|
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#ifndef STATIC_MODULES |
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void |
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_modinit(void) |
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{ |
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mod_add_cmd(&cryptlink_msgtab); |
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} |
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|
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void |
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_moddeinit(void) |
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{ |
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mod_del_cmd(&cryptlink_msgtab); |
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} |
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|
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const char *_version = "$Revision$"; |
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#endif |
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|
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|
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/* mr_cryptlink - CRYPTLINK message handler |
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* parv[0] == CRYPTLINK |
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* parv[1] = command (SERV, AUTH) |
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* parv[2] = Parameters specific to each command (parv[1]): |
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* SERV - parc must be >= 5 |
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* parv[0] == CRYPTLINK |
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* parv[1] == SERV |
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* parv[2] == server name |
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* parv[3] == keyphrase |
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* parv[4] == :server info (M-line) |
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* AUTH - parc must be >= 4 |
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* parv[0] == CRYPTLINK |
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* parv[1] == AUTH |
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* parv[2] == cipher (eg. BF/168) |
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* parv[3] == keyphrase |
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*/ |
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static void |
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mr_cryptlink(struct Client *client_p, struct Client *source_p, |
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int parc, char *parv[]) |
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{ |
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int i; |
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|
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for (i = 0; cryptlink_cmd_table[i].handler; i++) |
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{ |
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/* Traverse through the command table */ |
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if (!irccmp(cryptlink_cmd_table[i].cmd, parv[1])) |
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{ |
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/* |
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* Match found. Time to execute the function |
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*/ |
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cryptlink_cmd_table[i].handler(client_p, source_p, parc, parv); |
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} |
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} |
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} |
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|
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/* |
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* cryptlink_auth - CRYPTLINK AUTH message handler |
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* parv[1] = secret key |
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*/ |
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static void |
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cryptlink_auth(struct Client *client_p, struct Client *source_p, |
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int parc, char *parv[]) |
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{ |
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struct EncCapability *ecap; |
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struct ConfItem *conf; |
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struct AccessItem *aconf; |
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int enc_len; |
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int len; |
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unsigned char *enc; |
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unsigned char *key; |
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|
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if (parc < 4) |
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{ |
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cryptlink_error(client_p, "AUTH", "Invalid params", |
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"CRYPTLINK AUTH - Invalid params"); |
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return; |
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} |
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|
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if (!IsWaitAuth(client_p)) |
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return; |
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|
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for (ecap = CipherTable; ecap->name; ecap++) |
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{ |
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if ((!irccmp(ecap->name, parv[2])) && |
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(IsCapableEnc(client_p, ecap->cap))) |
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{ |
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client_p->localClient->in_cipher = ecap; |
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break; |
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} |
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} |
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|
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if (client_p->localClient->in_cipher == NULL) |
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{ |
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cryptlink_error(client_p, "AUTH", "Invalid cipher", "Invalid cipher"); |
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return; |
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} |
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|
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if (!(enc_len = unbase64_block(&enc, parv[3], strlen(parv[3])))) |
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{ |
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cryptlink_error(client_p, "AUTH", |
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"Could not base64 decode response", |
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"Malformed CRYPTLINK AUTH reply"); |
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return; |
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} |
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|
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if (verify_private_key() == -1) |
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{ |
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sendto_realops_flags(UMODE_ALL, L_ADMIN, |
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"verify_private_key() returned -1. Check log for information."); |
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} |
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|
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key = MyMalloc(RSA_size(ServerInfo.rsa_private_key)); |
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len = RSA_private_decrypt(enc_len, (unsigned char *)enc,(unsigned char *)key, |
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ServerInfo.rsa_private_key, |
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RSA_PKCS1_PADDING); |
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|
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if (len < client_p->localClient->in_cipher->keylen) |
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{ |
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report_crypto_errors(); |
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if (len < 0) |
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{ |
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cryptlink_error(client_p, "AUTH", |
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"Decryption failed", |
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"Malformed CRYPTLINK AUTH reply"); |
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} |
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else |
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{ |
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cryptlink_error(client_p, "AUTH", |
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"Not enough random data sent", |
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"Malformed CRYPTLINK AUTH reply"); |
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} |
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MyFree(enc); |
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MyFree(key); |
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return; |
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} |
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|
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if (memcmp(key, client_p->localClient->in_key, |
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client_p->localClient->in_cipher->keylen) != 0) |
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{ |
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cryptlink_error(client_p, "AUTH", |
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"Unauthorized server connection attempt", |
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"Malformed CRYPTLINK AUTH reply"); |
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return; |
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} |
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|
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conf = find_conf_name(&client_p->localClient->confs, |
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client_p->name, SERVER_TYPE); |
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|
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if (conf == NULL) |
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{ |
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cryptlink_error(client_p, "AUTH", |
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"Lost C-line for server", |
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"Lost C-line"); |
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return; |
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} |
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|
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aconf = (struct AccessItem *)map_to_conf(conf); |
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|
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if (!(client_p->localClient->out_cipher || |
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(client_p->localClient->out_cipher = check_cipher(client_p, aconf)))) |
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{ |
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cryptlink_error(client_p, "AUTH", |
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"Couldn't find compatible cipher", |
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"Couldn't find compatible cipher"); |
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return; |
247 |
} |
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|
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/* set hopcount */ |
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client_p->hopcount = 1; |
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|
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SetCryptIn(client_p); |
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ClearWaitAuth(client_p); |
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server_estab(client_p); |
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} |
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|
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/* |
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* cryptlink_serv - CRYPTLINK SERV message handler |
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* parv[0] == CRYPTLINK |
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* parv[1] == SERV |
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* parv[2] == server name |
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* parv[3] == keyphrase |
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* parv[4] == :server info (M-line) |
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*/ |
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static void |
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cryptlink_serv(struct Client *client_p, struct Client *source_p, |
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int parc, char *parv[]) |
268 |
{ |
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char info[REALLEN + 1]; |
270 |
char *name; |
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struct Client *target_p; |
272 |
char *key = client_p->localClient->out_key; |
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unsigned char *b64_key; |
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struct ConfItem *conf; |
275 |
struct AccessItem *aconf; |
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char *encrypted; |
277 |
const char *p; |
278 |
int enc_len; |
279 |
|
280 |
/* |
281 |
if (client_p->name[0] != 0) |
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return; |
283 |
*/ |
284 |
|
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if ((parc < 5) || (*parv[4] == '\0')) |
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{ |
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cryptlink_error(client_p, "SERV", "Invalid params", |
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"CRYPTLINK SERV - Invalid params"); |
289 |
return; |
290 |
} |
291 |
|
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if ((name = parse_cryptserv_args(client_p, parv, parc, info, key)) == NULL) |
293 |
{ |
294 |
cryptlink_error(client_p, "SERV", "Invalid params", |
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"CRYPTLINK SERV - Invalid params"); |
296 |
return; |
297 |
} |
298 |
|
299 |
/* CRYPTLINK SERV support => TS support */ |
300 |
client_p->tsinfo = TS_DOESTS; |
301 |
|
302 |
if (bogus_host(name)) |
303 |
{ |
304 |
exit_client(client_p, client_p, "Bogus server name"); |
305 |
return; |
306 |
} |
307 |
|
308 |
/* Now we just have to call check_server and everything should be |
309 |
* checked for us... -A1kmm. */ |
310 |
switch (check_server(name, client_p, CHECK_SERVER_CRYPTLINK)) |
311 |
{ |
312 |
case -1: |
313 |
if (ConfigFileEntry.warn_no_nline) |
314 |
{ |
315 |
cryptlink_error(client_p, "SERV", |
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"Unauthorized server connection attempt: No entry for server", |
317 |
NULL); |
318 |
} |
319 |
exit_client(client_p, client_p, "Invalid server name"); |
320 |
return; |
321 |
break; |
322 |
case -2: |
323 |
cryptlink_error(client_p, "SERV", |
324 |
"Unauthorized server connection attempt: CRYPTLINK not " |
325 |
"enabled on remote server", |
326 |
"CRYPTLINK not enabled"); |
327 |
return; |
328 |
break; |
329 |
case -3: |
330 |
cryptlink_error(client_p, "SERV", |
331 |
"Unauthorized server connection attempt: Invalid host", |
332 |
"Invalid host"); |
333 |
return; |
334 |
break; |
335 |
} |
336 |
|
337 |
if ((target_p = find_server(name))) |
338 |
{ |
339 |
/* |
340 |
* This link is trying feed me a server that I already have |
341 |
* access through another path -- multiple paths not accepted |
342 |
* currently, kill this link immediately!! |
343 |
* |
344 |
* Rather than KILL the link which introduced it, KILL the |
345 |
* youngest of the two links. -avalon |
346 |
* |
347 |
* Definitely don't do that here. This is from an unregistered |
348 |
* connect - A1kmm. |
349 |
*/ |
350 |
cryptlink_error(client_p, "SERV", |
351 |
"Attempt to re-introduce existing server", |
352 |
"Server Exists"); |
353 |
return; |
354 |
} |
355 |
|
356 |
if (ServerInfo.hub && IsCapable(client_p, CAP_LL)) |
357 |
{ |
358 |
if (IsCapable(client_p, CAP_HUB)) |
359 |
{ |
360 |
ClearCap(client_p,CAP_LL); |
361 |
sendto_realops_flags(UMODE_ALL, L_ALL, |
362 |
"*** LazyLinks to a hub from a hub, that's a no-no."); |
363 |
} |
364 |
else |
365 |
{ |
366 |
client_p->localClient->serverMask = nextFreeMask(); |
367 |
|
368 |
if(!client_p->localClient->serverMask) |
369 |
{ |
370 |
sendto_realops_flags(UMODE_ALL, L_ALL, |
371 |
"serverMask is full!"); |
372 |
/* try and negotiate a non LL connect */ |
373 |
ClearCap(client_p,CAP_LL); |
374 |
} |
375 |
} |
376 |
} |
377 |
else if (IsCapable(client_p, CAP_LL)) |
378 |
{ |
379 |
if (!IsCapable(client_p, CAP_HUB)) |
380 |
{ |
381 |
ClearCap(client_p,CAP_LL); |
382 |
sendto_realops_flags(UMODE_ALL, L_ALL, |
383 |
"*** LazyLinks to a leaf from a leaf, that's a no-no."); |
384 |
} |
385 |
} |
386 |
|
387 |
conf = find_conf_name(&client_p->localClient->confs, |
388 |
name, SERVER_TYPE); |
389 |
if (conf == NULL) |
390 |
{ |
391 |
cryptlink_error(client_p, "AUTH", |
392 |
"Lost C-line for server", |
393 |
"Lost C-line" ); |
394 |
return; |
395 |
} |
396 |
|
397 |
/* |
398 |
* if we are connecting (Handshake), we already have the name from the |
399 |
* connect {} block in client_p->name |
400 |
*/ |
401 |
strlcpy(client_p->name, name, sizeof(client_p->name)); |
402 |
|
403 |
p = info; |
404 |
|
405 |
if (!strncmp(info, "(H)", 3)) |
406 |
{ |
407 |
SetHidden(client_p); |
408 |
|
409 |
if ((p = strchr(info, ' ')) != NULL) |
410 |
{ |
411 |
p++; |
412 |
if (*p == '\0') |
413 |
p = "(Unknown Location)"; |
414 |
} |
415 |
else |
416 |
p = "(Unknown Location)"; |
417 |
} |
418 |
|
419 |
strlcpy(client_p->info, p, sizeof(client_p->info)); |
420 |
client_p->hopcount = 0; |
421 |
|
422 |
aconf = (struct AccessItem *)map_to_conf(conf); |
423 |
|
424 |
if (!(client_p->localClient->out_cipher || |
425 |
(client_p->localClient->out_cipher = check_cipher(client_p, aconf)))) |
426 |
{ |
427 |
cryptlink_error(client_p, "AUTH", |
428 |
"Couldn't find compatible cipher", |
429 |
"Couldn't find compatible cipher"); |
430 |
return; |
431 |
} |
432 |
|
433 |
encrypted = MyMalloc(RSA_size(ServerInfo.rsa_private_key)); |
434 |
enc_len = RSA_public_encrypt(client_p->localClient->out_cipher->keylen, |
435 |
(unsigned char *)key, |
436 |
(unsigned char *)encrypted, |
437 |
aconf->rsa_public_key, |
438 |
RSA_PKCS1_PADDING); |
439 |
|
440 |
if (enc_len <= 0) |
441 |
{ |
442 |
report_crypto_errors(); |
443 |
MyFree(encrypted); |
444 |
cryptlink_error(client_p, "AUTH", |
445 |
"Couldn't encrypt data", |
446 |
"Couldn't encrypt data"); |
447 |
return; |
448 |
} |
449 |
|
450 |
base64_block(&b64_key, encrypted, enc_len); |
451 |
|
452 |
MyFree(encrypted); |
453 |
|
454 |
if (!IsWaitAuth(client_p)) |
455 |
{ |
456 |
cryptlink_init(client_p, conf, NULL); |
457 |
} |
458 |
|
459 |
sendto_one(client_p, "CRYPTLINK AUTH %s %s", |
460 |
client_p->localClient->out_cipher->name, |
461 |
b64_key); |
462 |
|
463 |
/* needed for old servers that can't shove data back into slink */ |
464 |
send_queued_write(client_p); |
465 |
|
466 |
SetCryptOut(client_p); |
467 |
MyFree(b64_key); |
468 |
} |
469 |
|
470 |
/* parse_cryptserv_args() |
471 |
* |
472 |
* inputs - parv parameters |
473 |
* - parc count |
474 |
* - info string (to be filled in by this routine) |
475 |
* - key (to be filled in by this routine) |
476 |
* output - NULL if invalid params, server name otherwise |
477 |
* side effects - parv[2] is trimmed to HOSTLEN size if needed. |
478 |
*/ |
479 |
static char * |
480 |
parse_cryptserv_args(struct Client *client_p, char *parv[], |
481 |
int parc, char *info, char *key) |
482 |
{ |
483 |
char *name; |
484 |
unsigned char *tmp, *out; |
485 |
int len; |
486 |
int decoded_len; |
487 |
|
488 |
info[0] = '\0'; |
489 |
|
490 |
name = parv[2]; |
491 |
|
492 |
/* parv[2] contains encrypted auth data */ |
493 |
if (!(decoded_len = unbase64_block(&tmp, parv[3], |
494 |
strlen(parv[3])))) |
495 |
{ |
496 |
cryptlink_error(client_p, "SERV", |
497 |
"Couldn't base64 decode data", |
498 |
NULL); |
499 |
return(NULL); |
500 |
} |
501 |
|
502 |
if (verify_private_key() == -1) |
503 |
{ |
504 |
sendto_realops_flags(UMODE_ALL, L_ADMIN, |
505 |
"verify_private_key() returned -1. Check log for information."); |
506 |
} |
507 |
|
508 |
if (ServerInfo.rsa_private_key == NULL) |
509 |
{ |
510 |
cryptlink_error(client_p, "SERV", "No local private key found", NULL); |
511 |
return(NULL); |
512 |
} |
513 |
|
514 |
out = MyMalloc(RSA_size(ServerInfo.rsa_private_key)); |
515 |
len = RSA_private_decrypt(decoded_len, tmp, out, |
516 |
ServerInfo.rsa_private_key, |
517 |
RSA_PKCS1_PADDING); |
518 |
|
519 |
MyFree(tmp); |
520 |
|
521 |
if (len < CIPHERKEYLEN) |
522 |
{ |
523 |
report_crypto_errors(); |
524 |
if (len < 0) |
525 |
{ |
526 |
cryptlink_error(client_p, "AUTH", "Decryption failed", NULL); |
527 |
} |
528 |
else |
529 |
{ |
530 |
cryptlink_error(client_p, "AUTH", "Not enough random data sent", NULL); |
531 |
} |
532 |
MyFree(out); |
533 |
return(NULL); |
534 |
} |
535 |
|
536 |
memcpy(key, out, CIPHERKEYLEN); |
537 |
MyFree(out); |
538 |
|
539 |
strlcpy(info, parv[4], REALLEN + 1); |
540 |
|
541 |
if (strlen(name) > HOSTLEN) |
542 |
name[HOSTLEN] = '\0'; |
543 |
|
544 |
return(name); |
545 |
} |
546 |
|
547 |
/* bogus_host() |
548 |
* |
549 |
* inputs - hostname |
550 |
* output - 1 if a bogus hostname input, 0 if its valid |
551 |
* side effects - none |
552 |
*/ |
553 |
static int |
554 |
bogus_host(char *host) |
555 |
{ |
556 |
unsigned int length = 0; |
557 |
unsigned int dots = 0; |
558 |
char *s = host; |
559 |
|
560 |
for (; *s; s++) |
561 |
{ |
562 |
if (!IsServChar(*s)) |
563 |
return(1); |
564 |
|
565 |
++length; |
566 |
|
567 |
if ('.' == *s) |
568 |
++dots; |
569 |
} |
570 |
|
571 |
return(!dots || length > HOSTLEN); |
572 |
} |