elemental-ircd/modules/m_challenge.c

318 lines
8.9 KiB
C

/*
* ircd-ratbox: A slightly useful ircd.
* m_challenge.c: Allows an IRC Operator to securely authenticate.
*
* Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
* Copyright (C) 1996-2002 Hybrid Development Team
* Copyright (C) 2002-2005 ircd-ratbox development team
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*
* $Id: m_challenge.c 3161 2007-01-25 07:23:01Z nenolod $
*/
#include "stdinc.h"
#ifdef HAVE_LIBCRYPTO
#include <openssl/pem.h>
#include <openssl/rand.h>
#include <openssl/rsa.h>
#include <openssl/md5.h>
#include <openssl/bn.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#endif
#include "client.h"
#include "ircd.h"
#include "modules.h"
#include "numeric.h"
#include "send.h"
#include "s_conf.h"
#include "msg.h"
#include "parse.h"
#include "irc_string.h"
#include "s_log.h"
#include "s_user.h"
#include "cache.h"
#include "s_newconf.h"
#define CHALLENGE_WIDTH BUFSIZE - (NICKLEN + HOSTLEN + 12)
#define CHALLENGE_EXPIRES 180 /* 180 seconds should be more than long enough */
#define CHALLENGE_SECRET_LENGTH 128 /* how long our challenge secret should be */
#ifndef HAVE_LIBCRYPTO
/* Maybe this should be an error or something?-davidt */
/* now it is -larne */
static int challenge_load(void)
{
#ifndef STATIC_MODULES
sendto_realops_snomask(SNO_GENERAL, L_ALL,
"Challenge module not loaded because OpenSSL is not available.");
ilog(L_MAIN, "Challenge module not loaded because OpenSSL is not available.");
return -1;
#else
return 0;
#endif
}
DECLARE_MODULE_AV1(challenge, challenge_load, NULL, NULL, NULL, NULL, "$Revision: 3161 $");
#else
static int m_challenge(struct Client *, struct Client *, int, const char **);
/* We have openssl support, so include /CHALLENGE */
struct Message challenge_msgtab = {
"CHALLENGE", 0, 0, 0, MFLG_SLOW,
{mg_unreg, {m_challenge, 2}, mg_ignore, mg_ignore, mg_ignore, {m_challenge, 2}}
};
mapi_clist_av1 challenge_clist[] = { &challenge_msgtab, NULL };
DECLARE_MODULE_AV1(challenge, NULL, NULL, challenge_clist, NULL, NULL, "$Revision: 3161 $");
static int generate_challenge(char **r_challenge, char **r_response, RSA * key);
static void
cleanup_challenge(struct Client *target_p)
{
if(target_p->localClient == NULL)
return;
MyFree(target_p->localClient->challenge);
MyFree(target_p->localClient->opername);
target_p->localClient->challenge = NULL;
target_p->localClient->opername = NULL;
target_p->localClient->chal_time = 0;
}
/*
* m_challenge - generate RSA challenge for wouldbe oper
* parv[0] = sender prefix
* parv[1] = operator to challenge for, or +response
*
*/
static int
m_challenge(struct Client *client_p, struct Client *source_p, int parc, const char *parv[])
{
struct oper_conf *oper_p;
char *challenge = NULL; /* to placate gcc */
char chal_line[CHALLENGE_WIDTH];
unsigned char *b_response;
size_t cnt;
int len = 0;
/* if theyre an oper, reprint oper motd and ignore */
if(IsOper(source_p))
{
sendto_one(source_p, form_str(RPL_YOUREOPER), me.name, source_p->name);
send_oper_motd(source_p);
return 0;
}
if(*parv[1] == '+')
{
/* Ignore it if we aren't expecting this... -A1kmm */
if(!source_p->localClient->challenge)
return 0;
if((CurrentTime - source_p->localClient->chal_time) > CHALLENGE_EXPIRES)
{
sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
ilog(L_FOPER, "EXPIRED CHALLENGE (%s) by (%s!%s@%s) (%s)",
source_p->localClient->opername, source_p->name,
source_p->username, source_p->host, source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Expired CHALLENGE attempt by %s (%s@%s)",
source_p->name, source_p->username,
source_p->host);
cleanup_challenge(source_p);
return 0;
}
b_response = ircd_base64_decode((const unsigned char *)++parv[1], strlen(parv[1]), &len);
if(len != SHA_DIGEST_LENGTH ||
memcmp(source_p->localClient->challenge, b_response, SHA_DIGEST_LENGTH))
{
sendto_one(source_p, form_str(ERR_PASSWDMISMATCH), me.name, source_p->name);
ilog(L_FOPER, "FAILED CHALLENGE (%s) by (%s!%s@%s) (%s)",
source_p->localClient->opername, source_p->name,
source_p->username, source_p->host, source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Failed CHALLENGE attempt by %s (%s@%s)",
source_p->name, source_p->username,
source_p->host);
MyFree(b_response);
cleanup_challenge(source_p);
return 0;
}
MyFree(b_response);
oper_p = find_oper_conf(source_p->username, source_p->orighost,
source_p->sockhost,
source_p->localClient->opername);
if(oper_p == NULL)
{
sendto_one(source_p, form_str(ERR_NOOPERHOST),
me.name, source_p->name);
ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
source_p->localClient->opername, source_p->name,
source_p->username, source_p->host,
source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
source_p->name, source_p->username,
source_p->host);
return 0;
}
cleanup_challenge(source_p);
oper_up(source_p, oper_p);
ilog(L_OPERED, "OPER %s by %s!%s@%s (%s)",
source_p->localClient->opername, source_p->name,
source_p->username, source_p->host, source_p->sockhost);
return 0;
}
cleanup_challenge(source_p);
oper_p = find_oper_conf(source_p->username, source_p->orighost,
source_p->sockhost, parv[1]);
if(oper_p == NULL)
{
sendto_one(source_p, form_str(ERR_NOOPERHOST), me.name, source_p->name);
ilog(L_FOPER, "FAILED OPER (%s) by (%s!%s@%s) (%s)",
parv[1], source_p->name,
source_p->username, source_p->host, source_p->sockhost);
if(ConfigFileEntry.failed_oper_notice)
sendto_realops_snomask(SNO_GENERAL, L_NETWIDE,
"Failed CHALLENGE attempt - host mismatch by %s (%s@%s)",
source_p->name, source_p->username, source_p->host);
return 0;
}
if(!oper_p->rsa_pubkey)
{
sendto_one_notice(source_p, ":I'm sorry, PK authentication is not enabled for your oper{} block.");
return 0;
}
if(!generate_challenge(&challenge, &(source_p->localClient->challenge), oper_p->rsa_pubkey))
{
char *chal = challenge;
source_p->localClient->chal_time = CurrentTime;
for(;;)
{
cnt = strlcpy(chal_line, chal, CHALLENGE_WIDTH);
sendto_one(source_p, form_str(RPL_RSACHALLENGE2), me.name, source_p->name, chal_line);
if(cnt > CHALLENGE_WIDTH)
chal += CHALLENGE_WIDTH - 1;
else
break;
}
sendto_one(source_p, form_str(RPL_ENDOFRSACHALLENGE2),
me.name, source_p->name);
MyFree(challenge);
DupString(source_p->localClient->opername, oper_p->name);
}
else
sendto_one_notice(source_p, ":Failed to generate challenge.");
return 0;
}
static int
get_randomness(unsigned char *buf, int length)
{
/* Seed OpenSSL PRNG with EGD enthropy pool -kre */
if(ConfigFileEntry.use_egd && (ConfigFileEntry.egdpool_path != NULL))
{
if(RAND_egd(ConfigFileEntry.egdpool_path) == -1)
return -1;
}
if(RAND_status())
{
if(RAND_bytes(buf, length) > 0)
return 1;
}
else {
if(RAND_pseudo_bytes(buf, length) >= 0)
return 1;
}
return 0;
}
static int
generate_challenge(char **r_challenge, char **r_response, RSA * rsa)
{
SHA_CTX ctx;
unsigned char secret[CHALLENGE_SECRET_LENGTH], *tmp;
unsigned long length;
unsigned long e = 0;
unsigned long cnt = 0;
int ret;
if(!rsa)
return -1;
if(get_randomness(secret, CHALLENGE_SECRET_LENGTH))
{
SHA1_Init(&ctx);
SHA1_Update(&ctx, (u_int8_t *)secret, CHALLENGE_SECRET_LENGTH);
*r_response = MyMalloc(SHA_DIGEST_LENGTH);
SHA1_Final((u_int8_t *)*r_response, &ctx);
length = RSA_size(rsa);
tmp = MyMalloc(length);
ret = RSA_public_encrypt(CHALLENGE_SECRET_LENGTH, secret, tmp, rsa, RSA_PKCS1_OAEP_PADDING);
if (ret >= 0)
{
*r_challenge = (char *)ircd_base64_encode(tmp, ret);
MyFree(tmp);
return 0;
}
MyFree(tmp);
MyFree(*r_response);
*r_response = NULL;
}
ERR_load_crypto_strings();
while ((cnt < 100) && (e = ERR_get_error()))
{
ilog(L_MAIN, "SSL error: %s", ERR_error_string(e, 0));
cnt++;
}
return (-1);
}
#endif /* HAVE_LIBCRYPTO */