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ircu2/ircd/ircd_cloaking.c

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/*
* IRC - Internet Relay Chat, ircd/ircd_cloaking.c
* Copyright (C) 1999 Thomas Helvey
*
* 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 1, 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.
*/
/** @file
* @brief Implementation of IP and host cloaking functions..
* @version $Id$
*/
#include "config.h"
#include "ircd_chattr.h"
#include "ircd_cloaking.h"
#include "ircd_defs.h"
#include "ircd_features.h"
#include "ircd_md5.h"
#include "ircd_snprintf.h"
#include "res.h"
#include <netinet/in.h>
#include <string.h>
#undef KEY1
#undef KEY2
#undef KEY3
#undef PREFIX
#define KEY1 feature_str(FEAT_HOST_HIDING_KEY1)
#define KEY2 feature_str(FEAT_HOST_HIDING_KEY2)
#define KEY3 feature_str(FEAT_HOST_HIDING_KEY3)
#define PREFIX feature_str(FEAT_HOST_HIDING_PREFIX)
/** Downsamples a 128bit result to 32bits (md5 -> unsigned int) */
static inline unsigned int downsample(unsigned char *i)
{
unsigned char r[4];
r[0] = i[0] ^ i[1] ^ i[2] ^ i[3];
r[1] = i[4] ^ i[5] ^ i[6] ^ i[7];
r[2] = i[8] ^ i[9] ^ i[10] ^ i[11];
r[3] = i[12] ^ i[13] ^ i[14] ^ i[15];
return ( ((unsigned int)r[0] << 24) +
((unsigned int)r[1] << 16) +
((unsigned int)r[2] << 8) +
(unsigned int)r[3]);
}
/** Downsamples a 128bit result to 24bits (md5 -> unsigned int) */
static inline unsigned int downsample24(unsigned char *i)
{
unsigned char r[4];
r[0] = i[0] ^ i[1] ^ i[2] ^ i[3] ^ i[4];
r[1] = i[5] ^ i[6] ^ i[7] ^ i[8] ^ i[9] ^ i[10];
r[2] = i[11] ^ i[12] ^ i[13] ^ i[14] ^ i[15];
return ( ((unsigned int)r[0] << 16) +
((unsigned int)r[1] << 8) +
(unsigned int)r[2]);
}
char *hidehost_ipv4(struct irc_in_addr *ip)
{
unsigned int a, b, c, d;
static char buf[512], res[512], res2[512], result[128];
unsigned long n;
unsigned int alpha, beta, gamma, delta;
unsigned char *pch;
/*
* Output: ALPHA.BETA.GAMMA.DELTA.IP
* ALPHA is unique for a.b.c.d
* BETA is unique for a.b.c.*
* GAMMA is unique for a.b.*
* We cloak like this:
* ALPHA = downsample24(md5(md5("KEY2:A.B.C.D:KEY3")+"KEY1"));
* BETA = downsample24(md5(md5("KEY3:A.B.C:KEY1")+"KEY2"));
* GAMMA = downsample24(md5(md5("KEY1:A.B:KEY2")+"KEY3"));
* DELTA = downsample24(md5(md5("KEY2:A:KEY1:KEY3")+"KEY1"));
*/
if (!irc_in_addr_is_ipv4(ip))
return hidehost_ipv6(ip);
pch = (unsigned char*)&ip->in6_16[6];
a = *pch++;
b = *pch;
pch = (unsigned char*)&ip->in6_16[7];
c = *pch++;
d = *pch;
/* ALPHA... */
ircd_snprintf(0, buf, 512, "%s:%d.%d.%d.%d:%s", KEY2, a, b, c, d, KEY3);
DoMD5((unsigned char *)&res, (unsigned char *)&buf, strlen(buf));
strcpy(res+16, KEY1); /* first 16 bytes are filled, append our key.. */
n = strlen(res+16) + 16;
DoMD5((unsigned char *)&res2, (unsigned char *)&res, n);
alpha = downsample24((unsigned char *)&res2);
/* BETA... */
ircd_snprintf(0, buf, 512, "%s:%d.%d.%d:%s", KEY3, a, b, c, KEY1);
DoMD5((unsigned char *)&res, (unsigned char *)&buf, strlen(buf));
strcpy(res+16, KEY2); /* first 16 bytes are filled, append our key.. */
n = strlen(res+16) + 16;
DoMD5((unsigned char *)&res2, (unsigned char *)&res, n);
beta = downsample24((unsigned char *)&res2);
/* GAMMA... */
ircd_snprintf(0, buf, 512, "%s:%d.%d:%s", KEY1, a, b, KEY2);
DoMD5((unsigned char *)&res, (unsigned char *)&buf, strlen(buf));
strcpy(res+16, KEY3); /* first 16 bytes are filled, append our key.. */
n = strlen(res+16) + 16;
DoMD5((unsigned char *)&res2, (unsigned char *)&res, n);
gamma = downsample24((unsigned char *)&res2);
/* DELTA... */
ircd_snprintf(0, buf, 512, "%s:%d:%s:%s", KEY2, a, KEY1, KEY3);
DoMD5((unsigned char *)&res, (unsigned char *)&buf, strlen(buf));
strcpy(res+16, KEY1); /* first 16 bytes are filled, append our key.. */
n = strlen(res+16) + 16;
DoMD5((unsigned char *)&res2, (unsigned char *)&res, n);
delta = downsample24((unsigned char *)&res2);
ircd_snprintf(0, result, HOSTLEN, "%X.%X.%X.%X.IP", alpha, beta, gamma, delta);
return result;
}
char *hidehost_ipv6(struct irc_in_addr *ip)
{
unsigned int a, b, c, d, e, f, g, h;
static char buf[512], res[512], res2[512], result[128];
unsigned long n;
unsigned int alpha, beta, gamma, delta;
/*
* Output: ALPHA:BETA:GAMMA:IP
* ALPHA is unique for a:b:c:d:e:f:g:h
* BETA is unique for a:b:c:d:e:f:g
* GAMMA is unique for a:b:c:d
* We cloak like this:
* ALPHA = downsample24(md5(md5("KEY2:a:b:c:d:e:f:g:h:KEY3")+"KEY1"));
* BETA = downsample24(md5(md5("KEY3:a:b:c:d:e:f:g:KEY1")+"KEY2"));
* GAMMA = downsample24(md5(md5("KEY1:a:b:c:d:KEY2")+"KEY3"));
* DELTA = downsample24(md5(md5("KEY2:a:b:KEY1:KEY3")+"KEY1"));
*/
if (irc_in_addr_is_ipv4(ip))
return hidehost_ipv4(ip);
a = ntohs(ip->in6_16[0]);
b = ntohs(ip->in6_16[1]);
c = ntohs(ip->in6_16[2]);
d = ntohs(ip->in6_16[3]);
e = ntohs(ip->in6_16[4]);
f = ntohs(ip->in6_16[5]);
g = ntohs(ip->in6_16[6]);
h = ntohs(ip->in6_16[7]);
/* ALPHA... */
ircd_snprintf(0, buf, 512, "%s:%x:%x:%x:%x:%x:%x:%x:%x:%s", KEY2, a, b, c, d, e, f, g, h, KEY3);
DoMD5((unsigned char *)&res, (unsigned char *)&buf, strlen(buf));
strcpy(res+16, KEY1); /* first 16 bytes are filled, append our key.. */
n = strlen(res+16) + 16;
DoMD5((unsigned char *)&res2, (unsigned char *)&res, n);
alpha = downsample24((unsigned char *)&res2);
/* BETA... */
ircd_snprintf(0, buf, 512, "%s:%x:%x:%x:%x:%x:%x:%x:%s", KEY3, a, b, c, d, e, f, g, KEY1);
DoMD5((unsigned char *)&res, (unsigned char *)&buf, strlen(buf));
strcpy(res+16, KEY2); /* first 16 bytes are filled, append our key.. */
n = strlen(res+16) + 16;
DoMD5((unsigned char *)&res2, (unsigned char *)&res, n);
beta = downsample24((unsigned char *)&res2);
/* GAMMA... */
ircd_snprintf(0, buf, 512, "%s:%x:%x:%x:%x:%s", KEY1, a, b, c, d, KEY2);
DoMD5((unsigned char *)&res, (unsigned char *)&buf, strlen(buf));
strcpy(res+16, KEY3); /* first 16 bytes are filled, append our key.. */
n = strlen(res+16) + 16;
DoMD5((unsigned char *)&res2, (unsigned char *)&res, n);
gamma = downsample24((unsigned char *)&res2);
/* DELTA... */
ircd_snprintf(0, buf, 512, "%s:%x:%x:%s:%s", KEY2, a, b, KEY1, KEY3);
DoMD5((unsigned char *)&res, (unsigned char *)&buf, strlen(buf));
strcpy(res+16, KEY1); /* first 16 bytes are filled, append our key.. */
n = strlen(res+16) + 16;
DoMD5((unsigned char *)&res2, (unsigned char *)&res, n);
delta = downsample24((unsigned char *)&res2);
ircd_snprintf(0, result, HOSTLEN, "%X:%X:%X:%X:IP", alpha, beta, gamma, delta);
return result;
}
char *hidehost_normalhost(char *host, int components)
{
char *p, *c;
static char buf[512], res[512], res2[512], result[HOSTLEN+1];
unsigned int alpha, n;
int comps = 0;
ircd_snprintf(0, buf, 512, "%s:%s:%s", KEY1, host, KEY2);
DoMD5((unsigned char *)&res, (unsigned char *)&buf, strlen(buf));
strcpy(res+16, KEY3); /* first 16 bytes are filled, append our key.. */
n = strlen(res+16) + 16;
DoMD5((unsigned char *)&res2, (unsigned char *)&res, n);
alpha = downsample((unsigned char *)&res2);
for (p = host; *p; p++) {
if (*p == '.') {
comps++;
if ((comps >= components) && IsHostChar(*(p + 1)))
break;
}
}
if (*p)
{
unsigned int len;
p++;
ircd_snprintf(0, result, HOSTLEN, "%s-%X.", PREFIX, alpha);
len = strlen(result) + strlen(p);
if (len <= HOSTLEN)
strcat(result, p);
else
{
c = p + (len - HOSTLEN);
if ((*c == '.') && *(c+1))
c++;
strcat(result, c);
}
} else
ircd_snprintf(0, result, HOSTLEN, "%s-%X", PREFIX, alpha);
return result;
}
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