elemental-ircd/extensions/ip_cloaking.c

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/*
* Charybdis: an advanced ircd
* ip_cloaking.c: provide user hostname cloaking
*
* Written originally by nenolod, altered to use FNV by Elizabeth in 2008
*/
#include "stdinc.h"
#include "modules.h"
#include "hook.h"
#include "client.h"
#include "ircd.h"
#include "send.h"
#include "hash.h"
#include "s_conf.h"
#include "s_user.h"
#include "s_serv.h"
#include "numeric.h"
static int
_modinit(void)
{
/* add the usermode to the available slot */
user_modes['x'] = find_umode_slot();
construct_umodebuf();
return 0;
}
static void
_moddeinit(void)
{
/* disable the umode and remove it from the available list */
user_modes['x'] = 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_p, char *newhost)
{
if (newhost != client_p->orighost)
sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :is now your hidden host",
newhost);
else
sendto_one_numeric(client_p, RPL_HOSTHIDDEN, "%s :hostname reset",
newhost);
sendto_server(NULL, NULL,
CAP_EUID | CAP_TS6, NOCAPS, ":%s CHGHOST %s :%s",
use_id(&me), use_id(client_p), newhost);
sendto_server(NULL, NULL,
CAP_TS6, CAP_EUID, ":%s ENCAP * CHGHOST %s :%s",
use_id(&me), use_id(client_p), newhost);
change_nick_user_host(client_p, client_p->name, client_p->username, newhost, 0, "Changing host");
if (newhost != client_p->orighost)
SetDynSpoof(client_p);
else
ClearDynSpoof(client_p);
}
static void
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do_host_cloak_ip(const char *inbuf, char *outbuf)
{
/* None of the characters in this table can be valid in an IP */
char chartable[] = "ghijklmnopqrstuvwxyz";
char *tptr;
uint32_t accum = fnv_hash((const unsigned char*) inbuf, 32);
int sepcount = 0;
int totalcount = 0;
int ipv6 = 0;
rb_strlcpy(outbuf, inbuf, HOSTLEN + 1);
if (strchr(outbuf, ':')) {
ipv6 = 1;
/* Damn you IPv6...
* We count the number of colons so we can calculate how much
* of the host to cloak. This is because some hostmasks may not
* have as many octets as we'd like.
*
* We have to do this ahead of time because doing this during
* the actual cloaking would get ugly
*/
for (tptr = outbuf; *tptr != '\0'; tptr++)
if (*tptr == ':')
totalcount++;
} else if (!strchr(outbuf, '.'))
return;
for (tptr = outbuf; *tptr != '\0'; tptr++) {
if (*tptr == ':' || *tptr == '.') {
sepcount++;
continue;
}
if (ipv6 && sepcount < totalcount / 2)
continue;
if (!ipv6 && sepcount < 2)
continue;
*tptr = chartable[(*tptr + accum) % 20];
accum = (accum << 1) | (accum >> 31);
}
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}
static void
do_host_cloak_host(const char *inbuf, char *outbuf)
{
char b26_alphabet[] = "abcdefghijklmnopqrstuvwxyz";
char *tptr;
uint32_t accum = fnv_hash((const unsigned char*) inbuf, 32);
rb_strlcpy(outbuf, inbuf, HOSTLEN + 1);
/* pass 1: scramble first section of hostname using base26
* alphabet toasted against the FNV hash 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];
/* Rotate one bit to avoid all digits being turned odd or even */
accum = (accum << 1) | (accum >> 31);
}
/* pass 2: scramble each number in the address */
for (tptr = outbuf; *tptr != '\0'; tptr++) {
if (isdigit(*tptr))
*tptr = '0' + (*tptr + accum) % 10;
accum = (accum << 1) | (accum >> 31);
}
}
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['x']))
return;
if (source_p->umodes & user_modes['x']) {
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['x'];
return;
}
if (strcmp(source_p->host, source_p->localClient->mangledhost)) {
distribute_hostchange(source_p, source_p->localClient->mangledhost);
} 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['x'])) {
if (source_p->localClient->mangledhost != NULL &&
!strcmp(source_p->host, source_p->localClient->mangledhost)) {
distribute_hostchange(source_p, source_p->orighost);
}
}
}
static void
check_new_user(void *vdata)
{
struct Client *source_p = (void *)vdata;
if (IsIPSpoof(source_p)) {
source_p->umodes &= ~user_modes['x'];
return;
}
source_p->localClient->mangledhost = rb_malloc(HOSTLEN + 1);
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['x'];
if (source_p->umodes & user_modes['x']) {
rb_strlcpy(source_p->host, source_p->localClient->mangledhost, sizeof(source_p->host));
if (irccmp(source_p->host, source_p->orighost))
SetDynSpoof(source_p);
}
}