elemental-ircd/extensions/ip_cloaking.c

220 lines
5.4 KiB
C

/* $Id: ip_cloaking.c 3526 2007-07-06 07:56:14Z nenolod $ */
#include "stdinc.h"
#include "modules.h"
#include "hook.h"
#include "client.h"
#include "ircd.h"
#include "send.h"
#include "s_conf.h"
#include "s_user.h"
#include "s_serv.h"
#include "numeric.h"
/* if you're modifying this module, you'll probably to change this */
#define KEY 0x13748cfa
static int
_modinit(void)
{
/* add the usermode to the available slot */
user_modes['h'] = find_umode_slot();
construct_umodebuf();
return 0;
}
static void
_moddeinit(void)
{
/* disable the umode and remove it from the available list */
user_modes['h'] = 0;
construct_umodebuf();
}
static void check_umode_change(void *data);
static void check_new_user(void *data);
mapi_hfn_list_av1 ip_cloaking_hfnlist[] = {
{ "umode_changed", (hookfn) check_umode_change },
{ "new_local_user", (hookfn) check_new_user },
{ NULL, NULL }
};
DECLARE_MODULE_AV1(ip_cloaking, _modinit, _moddeinit, NULL, NULL,
ip_cloaking_hfnlist, "$Revision: 3526 $");
static void
distribute_hostchange(struct Client *client)
{
if (irccmp(client->host, client->orighost))
sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :is now your hidden host",
client->host);
else
sendto_one_numeric(client, RPL_HOSTHIDDEN, "%s :hostname reset",
client->host);
sendto_server(NULL, NULL,
CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
use_id(&me), use_id(client), client->host);
sendto_server(NULL, NULL,
CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
use_id(&me), use_id(client), client->host);
sendto_server(NULL, NULL,
NOCAPS, CAP_TS6, ":%s ENCAP * CHGHOST %s :%s",
me.name, client->name, client->host);
if (irccmp(client->host, client->orighost))
SetDynSpoof(client);
else
ClearDynSpoof(client);
}
#define Nval 0x8c3a48ac
#define HOSTLEN 63
#define INITDATA "98fwqefnoiqefv03f423t34gbv3vb89tg432t3b8" /* change this */
static inline unsigned int
get_string_entropy(const char *inbuf)
{
unsigned int accum = 1;
while(*inbuf != '\0')
accum += *inbuf++;
return accum;
}
/* calls get_string_entropy() and toasts it against INITDATA */
static inline unsigned int
get_string_weighted_entropy(const char *inbuf)
{
static int base_entropy = 0;
unsigned int accum = get_string_entropy(inbuf);
/* initialize the algorithm if it is not yet ready */
if (base_entropy == 0)
base_entropy = get_string_entropy(INITDATA);
return (Nval * accum) ^ base_entropy;
}
static void
do_host_cloak_ip(const char *inbuf, char *outbuf)
{
char *tptr;
unsigned int accum = get_string_weighted_entropy(inbuf);
char buf[HOSTLEN];
strncpy(buf, inbuf, HOSTLEN);
tptr = strrchr(buf, '.');
if (tptr == NULL)
{
strncpy(outbuf, inbuf, HOSTLEN);
return;
}
*tptr++ = '\0';
snprintf(outbuf, HOSTLEN, "%s.%x", buf, accum);
}
static void
do_host_cloak_host(const char *inbuf, char *outbuf)
{
char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
char *tptr;
unsigned int accum = get_string_weighted_entropy(inbuf);
strncpy(outbuf, inbuf, HOSTLEN);
/* pass 1: scramble first section of hostname using base26
* alphabet toasted against the weighted entropy of the string.
*
* numbers are not changed at this time, only letters.
*/
for (tptr = outbuf; *tptr != '\0'; tptr++)
{
if (*tptr == '.')
break;
if (isdigit(*tptr) || *tptr == '-')
continue;
*tptr = b26_alphabet[(*tptr * accum) % 26];
}
/* pass 2: scramble each number in the address */
for (tptr = outbuf; *tptr != '\0'; tptr++)
{
if (isdigit(*tptr))
{
*tptr = 48 + ((*tptr * accum) % 10);
}
}
}
static void
check_umode_change(void *vdata)
{
hook_data_umode_changed *data = (hook_data_umode_changed *)vdata;
struct Client *source_p = data->client;
if (!MyClient(source_p))
return;
/* didn't change +h umode, we don't need to do anything */
if (!((data->oldumodes ^ source_p->umodes) & user_modes['h']))
return;
if (source_p->umodes & user_modes['h'])
{
if (IsIPSpoof(source_p) || source_p->localClient->mangledhost == NULL || (IsDynSpoof(source_p) && strcmp(source_p->host, source_p->localClient->mangledhost)))
{
source_p->umodes &= ~user_modes['h'];
return;
}
if (strcmp(source_p->host, source_p->localClient->mangledhost))
{
strlcpy(source_p->host, source_p->localClient->mangledhost, HOSTLEN);
distribute_hostchange(source_p);
}
else /* not really nice, but we need to send this numeric here */
sendto_one_numeric(source_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
source_p->host);
}
else if (!(source_p->umodes & user_modes['h']))
{
if (source_p->localClient->mangledhost != NULL &&
!strcmp(source_p->host, source_p->localClient->mangledhost))
{
strlcpy(source_p->host, source_p->orighost, HOSTLEN);
distribute_hostchange(source_p);
}
}
}
static void
check_new_user(void *vdata)
{
struct Client *source_p = (void *)vdata;
if (IsIPSpoof(source_p))
{
source_p->umodes &= ~user_modes['h'];
return;
}
source_p->localClient->mangledhost = rb_malloc(HOSTLEN);
if (!irccmp(source_p->orighost, source_p->sockhost))
do_host_cloak_ip(source_p->orighost, source_p->localClient->mangledhost);
else
do_host_cloak_host(source_p->orighost, source_p->localClient->mangledhost);
if (IsDynSpoof(source_p))
source_p->umodes &= ~user_modes['h'];
if (source_p->umodes & user_modes['h'])
{
strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host));
if (irccmp(source_p->host, source_p->orighost))
SetDynSpoof(source_p);
}
}