/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
* Copyright (C) 2006-2008 Robin Burchell <robin+git@viroteck.net>
* Copyright (C) 2008 Pippijn van Steenhoven <pip88nl@gmail.com>
* Copyright (C) 2003-2008 Craig Edwards <craigedwards@brainbox.cc>
* Copyright (C) 2007 John Brooks <john.brooks@dereferenced.net>
* Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
* Copyright (C) 2006 Oliver Lupton <oliverlupton@gmail.com>
*
* This file is part of InspIRCd. InspIRCd 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, version 2.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include "inspircd.h"
#include "hash.h"
/* $ModDesc: Provides masking of user hostnames */
enum CloakMode
{
/** 1.2-compatible host-based cloak */
MODE_COMPAT_HOST,
/** 1.2-compatible IP-only cloak */
MODE_COMPAT_IPONLY,
/** 2.0 cloak of "half" of the hostname plus the full IP hash */
MODE_HALF_CLOAK,
/** 2.0 cloak of IP hash, split at 2 common CIDR range points */
MODE_OPAQUE
};
// lowercase-only encoding similar to base64, used for hash output
static const char base32[] = "0123456789abcdefghijklmnopqrstuv";
/** Handles user mode +x
*/
class CloakUser : public ModeHandler
{
public:
LocalStringExt ext;
std::string debounce_uid;
time_t debounce_ts;
int debounce_count;
CloakUser(Module* source)
: ModeHandler(source, "cloak", 'x', PARAM_NONE, MODETYPE_USER),
ext("cloaked_host", source), debounce_ts(0), debounce_count(0)
{
}
ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string ¶meter, bool adding)
{
LocalUser* user = IS_LOCAL(dest);
/* For remote clients, we don't take any action, we just allow it.
* The local server where they are will set their cloak instead.
* This is fine, as we will receive it later.
*/
if (!user)
{
dest->SetMode('x',adding);
return MODEACTION_ALLOW;
}
if (user->uuid == debounce_uid && debounce_ts == ServerInstance->Time())
{
// prevent spamming using /mode user +x-x+x-x+x-x
if (++debounce_count > 2)
return MODEACTION_DENY;
}
else
{
debounce_uid = user->uuid;
debounce_count = 1;
debounce_ts = ServerInstance->Time();
}
if (adding == user->IsModeSet('x'))
return MODEACTION_DENY;
/* don't allow this user to spam modechanges */
if (source == dest)
user->CommandFloodPenalty += 5000;
if (adding)
{
std::string* cloak = ext.get(user);
if (!cloak)
{
/* Force creation of missing cloak */
creator->OnUserConnect(user);
cloak = ext.get(user);
}
if (cloak)
{
user->ChangeDisplayedHost(cloak->c_str());
user->SetMode('x',true);
return MODEACTION_ALLOW;
}
else
return MODEACTION_DENY;
}
else
{
/* User is removing the mode, so restore their real host
* and make it match the displayed one.
*/
user->SetMode('x',false);
user->ChangeDisplayedHost(user->host.c_str());
return MODEACTION_ALLOW;
}
}
};
class CommandCloak : public Command
{
public:
CommandCloak(Module* Creator) : Command(Creator, "CLOAK", 1)
{
flags_needed = 'o';
syntax = "<host>";
}
CmdResult Handle(const std::vector<std::string> ¶meters, User *user);
};
class ModuleCloaking : public Module
{
public:
CloakUser cu;
CloakMode mode;
CommandCloak ck;
std::string prefix;
std::string suffix;
std::string key;
unsigned int compatkey[4];
const char* xtab[4];
dynamic_reference<HashProvider> Hash;
ModuleCloaking() : cu(this), mode(MODE_OPAQUE), ck(this), Hash(this, "hash/md5")
{
}
void init()
{
OnRehash(NULL);
ServerInstance->Modules->AddService(cu);
ServerInstance->Modules->AddService(ck);
ServerInstance->Modules->AddService(cu.ext);
Implementation eventlist[] = { I_OnRehash, I_OnCheckBan, I_OnUserConnect, I_OnChangeHost };
ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
}
/** This function takes a domain name string and returns just the last two domain parts,
* or the last domain part if only two are available. Failing that it just returns what it was given.
*
* For example, if it is passed "svn.inspircd.org" it will return ".inspircd.org".
* If it is passed "brainbox.winbot.co.uk" it will return ".co.uk",
* and if it is passed "localhost.localdomain" it will return ".localdomain".
*
* This is used to ensure a significant part of the host is always cloaked (see Bug #216)
*/
std::string LastTwoDomainParts(const std::string &host)
{
int dots = 0;
std::string::size_type splitdot = host.length();
for (std::string::size_type x = host.length() - 1; x; --x)
{
if (host[x] == '.')
{
splitdot = x;
dots++;
}
if (dots >= 3)
break;
}
if (splitdot == host.length())
return "";
else
return host.substr(splitdot);
}
/**
* 2.0-style cloaking function
* @param item The item to cloak (part of an IP or hostname)
* @param id A unique ID for this type of item (to make it unique if the item matches)
* @param len The length of the output. Maximum for MD5 is 16 characters.
*/
std::string SegmentCloak(const std::string& item, char id, int len)
{
std::string input;
input.reserve(key.length() + 3 + item.length());
input.append(1, id);
input.append(key);
input.append(1, '\0'); // null does not terminate a C++ string
input.append(item);
std::string rv = Hash->sum(input).substr(0,len);
for(int i=0; i < len; i++)
{
// this discards 3 bits per byte. We have an
// overabundance of bits in the hash output, doesn't
// matter which ones we are discarding.
rv[i] = base32[rv[i] & 0x1F];
}
return rv;
}
std::string CompatCloak4(const char* ip)
{
irc::sepstream seps(ip, '.');
std::string octet[4];
int i[4];
for (int j = 0; j < 4; j++)
{
seps.GetToken(octet[j]);
i[j] = atoi(octet[j].c_str());
}
octet[3] = octet[0] + "." + octet[1] + "." + octet[2] + "." + octet[3];
octet[2] = octet[0] + "." + octet[1] + "." + octet[2];
octet[1] = octet[0] + "." + octet[1];
/* Reset the Hash module and send it our IV */
std::string rv;
/* Send the Hash module a different hex table for each octet group's Hash sum */
for (int k = 0; k < 4; k++)
{
rv.append(Hash->sumIV(compatkey, xtab[(compatkey[k]+i[k]) % 4], octet[k]).substr(0,6));
if (k < 3)
rv.append(".");
}
/* Stick them all together */
return rv;
}
std::string CompatCloak6(const char* ip)
{
std::vector<std::string> hashies;
std::string item;
int rounds = 0;
/* Reset the Hash module and send it our IV */
for (const char* input = ip; *input; input++)
{
item += *input;
if (item.length() > 7)
{
hashies.push_back(Hash->sumIV(compatkey, xtab[(compatkey[0]+rounds) % 4], item).substr(0,8));
item.clear();
}
rounds++;
}
if (!item.empty())
{
hashies.push_back(Hash->sumIV(compatkey, xtab[(compatkey[0]+rounds) % 4], item).substr(0,8));
}
/* Stick them all together */
return irc::stringjoiner(":", hashies, 0, hashies.size() - 1).GetJoined();
}
std::string SegmentIP(const irc::sockets::sockaddrs& ip, bool full)
{
std::string bindata;
int hop1, hop2, hop3;
int len1, len2;
std::string rv;
if (ip.sa.sa_family == AF_INET6)
{
bindata = std::string((const char*)ip.in6.sin6_addr.s6_addr, 16);
hop1 = 8;
hop2 = 6;
hop3 = 4;
len1 = 6;
len2 = 4;
// pfx s1.s2.s3. (xxxx.xxxx or s4) sfx
// 6 4 4 9/6
rv.reserve(prefix.length() + 26 + suffix.length());
}
else
{
bindata = std::string((const char*)&ip.in4.sin_addr, 4);
hop1 = 3;
hop2 = 0;
hop3 = 2;
len1 = len2 = 3;
// pfx s1.s2. (xxx.xxx or s3) sfx
rv.reserve(prefix.length() + 15 + suffix.length());
}
rv.append(prefix);
rv.append(SegmentCloak(bindata, 10, len1));
rv.append(1, '.');
bindata.erase(hop1);
rv.append(SegmentCloak(bindata, 11, len2));
if (hop2)
{
rv.append(1, '.');
bindata.erase(hop2);
rv.append(SegmentCloak(bindata, 12, len2));
}
if (full)
{
rv.append(1, '.');
bindata.erase(hop3);
rv.append(SegmentCloak(bindata, 13, 6));
rv.append(suffix);
}
else
{
char buf[50];
if (ip.sa.sa_family == AF_INET6)
{
snprintf(buf, 50, ".%02x%02x.%02x%02x%s",
ip.in6.sin6_addr.s6_addr[2], ip.in6.sin6_addr.s6_addr[3],
ip.in6.sin6_addr.s6_addr[0], ip.in6.sin6_addr.s6_addr[1], suffix.c_str());
}
else
{
const unsigned char* ip4 = (const unsigned char*)&ip.in4.sin_addr;
snprintf(buf, 50, ".%d.%d%s", ip4[1], ip4[0], suffix.c_str());
}
rv.append(buf);
}
return rv;
}
ModResult OnCheckBan(User* user, Channel* chan, const std::string& mask)
{
LocalUser* lu = IS_LOCAL(user);
if (!lu)
return MOD_RES_PASSTHRU;
OnUserConnect(lu);
std::string* cloak = cu.ext.get(user);
/* Check if they have a cloaked host, but are not using it */
if (cloak && *cloak != user->dhost)
{
char cmask[MAXBUF];
snprintf(cmask, MAXBUF, "%s!%s@%s", user->nick.c_str(), user->ident.c_str(), cloak->c_str());
if (InspIRCd::Match(cmask,mask))
return MOD_RES_DENY;
}
return MOD_RES_PASSTHRU;
}
void Prioritize()
{
/* Needs to be after m_banexception etc. */
ServerInstance->Modules->SetPriority(this, I_OnCheckBan, PRIORITY_LAST);
}
// this unsets umode +x on every host change. If we are actually doing a +x
// mode change, we will call SetMode back to true AFTER the host change is done.
void OnChangeHost(User* u, const std::string& host)
{
if(u->IsModeSet('x'))
{
u->SetMode('x', false);
u->WriteServ("MODE %s -x", u->nick.c_str());
}
}
~ModuleCloaking()
{
}
Version GetVersion()
{
std::string testcloak = "broken";
if (Hash)
{
switch (mode)
{
case MODE_COMPAT_HOST:
testcloak = prefix + "-" + Hash->sumIV(compatkey, xtab[0], "*").substr(0,10);
break;
case MODE_COMPAT_IPONLY:
testcloak = Hash->sumIV(compatkey, xtab[0], "*").substr(0,10);
break;
case MODE_HALF_CLOAK:
testcloak = prefix + SegmentCloak("*", 3, 8) + suffix;
break;
case MODE_OPAQUE:
testcloak = prefix + SegmentCloak("*", 4, 8) + suffix;
}
}
return Version("Provides masking of user hostnames", VF_COMMON|VF_VENDOR, testcloak);
}
void OnRehash(User* user)
{
ConfigTag* tag = ServerInstance->Config->ConfValue("cloak");
prefix = tag->getString("prefix");
suffix = tag->getString("suffix", ".IP");
std::string modestr = tag->getString("mode");
if (modestr == "compat-host")
mode = MODE_COMPAT_HOST;
else if (modestr == "compat-ip")
mode = MODE_COMPAT_IPONLY;
else if (modestr == "half")
mode = MODE_HALF_CLOAK;
else if (modestr == "full")
mode = MODE_OPAQUE;
else
throw ModuleException("Bad value for <cloak:mode>; must be one of compat-host, compat-ip, half, full");
if (mode == MODE_COMPAT_HOST || mode == MODE_COMPAT_IPONLY)
{
bool lowercase = tag->getBool("lowercase");
/* These are *not* using the need_positive parameter of ReadInteger -
* that will limit the valid values to only the positive values in a
* signed int. Instead, accept any value that fits into an int and
* cast it to an unsigned int. That will, a bit oddly, give us the full
* spectrum of an unsigned integer. - Special
*
* We must limit the keys or else we get different results on
* amd64/x86 boxes. - psychon */
const unsigned int limit = 0x80000000;
compatkey[0] = (unsigned int) tag->getInt("key1");
compatkey[1] = (unsigned int) tag->getInt("key2");
compatkey[2] = (unsigned int) tag->getInt("key3");
compatkey[3] = (unsigned int) tag->getInt("key4");
if (!lowercase)
{
xtab[0] = "F92E45D871BCA630";
xtab[1] = "A1B9D80C72E653F4";
xtab[2] = "1ABC078934DEF562";
xtab[3] = "ABCDEF5678901234";
}
else
{
xtab[0] = "f92e45d871bca630";
xtab[1] = "a1b9d80c72e653f4";
xtab[2] = "1abc078934def562";
xtab[3] = "abcdef5678901234";
}
if (prefix.empty())
prefix = ServerInstance->Config->Network;
if (!compatkey[0] || !compatkey[1] || !compatkey[2] || !compatkey[3] ||
compatkey[0] >= limit || compatkey[1] >= limit || compatkey[2] >= limit || compatkey[3] >= limit)
{
std::string detail;
if (!compatkey[0] || compatkey[0] >= limit)
detail = "<cloak:key1> is not valid, it may be set to a too high/low value, or it may not exist.";
else if (!compatkey[1] || compatkey[1] >= limit)
detail = "<cloak:key2> is not valid, it may be set to a too high/low value, or it may not exist.";
else if (!compatkey[2] || compatkey[2] >= limit)
detail = "<cloak:key3> is not valid, it may be set to a too high/low value, or it may not exist.";
else if (!compatkey[3] || compatkey[3] >= limit)
detail = "<cloak:key4> is not valid, it may be set to a too high/low value, or it may not exist.";
throw ModuleException("You have not defined cloak keys for m_cloaking!!! THIS IS INSECURE AND SHOULD BE CHECKED! - " + detail);
}
}
else
{
key = tag->getString("key");
if (key.empty() || key == "secret")
throw ModuleException("You have not defined cloak keys for m_cloaking. Define <cloak:key> as a network-wide secret.");
}
}
std::string GenCloak(const irc::sockets::sockaddrs& ip, const std::string& ipstr, const std::string& host)
{
std::string chost;
switch (mode)
{
case MODE_COMPAT_HOST:
{
if (ipstr != host)
{
std::string tail = LastTwoDomainParts(host);
// xtab is not used here due to a bug in 1.2 cloaking
chost = prefix + "-" + Hash->sumIV(compatkey, "0123456789abcdef", host).substr(0,8) + tail;
/* Fix by brain - if the cloaked host is > the max length of a host (64 bytes
* according to the DNS RFC) then they get cloaked as an IP.
*/
if (chost.length() <= 64)
break;
}
// fall through to IP cloak
}
case MODE_COMPAT_IPONLY:
if (ip.sa.sa_family == AF_INET6)
chost = CompatCloak6(ipstr.c_str());
else
chost = CompatCloak4(ipstr.c_str());
break;
case MODE_HALF_CLOAK:
{
if (ipstr != host)
chost = prefix + SegmentCloak(host, 1, 6) + LastTwoDomainParts(host);
if (chost.empty() || chost.length() > 50)
chost = SegmentIP(ip, false);
break;
}
case MODE_OPAQUE:
default:
chost = SegmentIP(ip, true);
}
return chost;
}
void OnUserConnect(LocalUser* dest)
{
std::string* cloak = cu.ext.get(dest);
if (cloak)
return;
cu.ext.set(dest, GenCloak(dest->client_sa, dest->GetIPString(), dest->host));
}
};
CmdResult CommandCloak::Handle(const std::vector<std::string> ¶meters, User *user)
{
ModuleCloaking* mod = (ModuleCloaking*)(Module*)creator;
irc::sockets::sockaddrs sa;
std::string cloak;
if (irc::sockets::aptosa(parameters[0], 0, sa))
cloak = mod->GenCloak(sa, parameters[0], parameters[0]);
else
cloak = mod->GenCloak(sa, "", parameters[0]);
user->WriteServ("NOTICE %s :*** Cloak for %s is %s", user->nick.c_str(), parameters[0].c_str(), cloak.c_str());
return CMD_SUCCESS;
}
MODULE_INIT(ModuleCloaking)
