/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2021 Herman <GermanAizek@yandex.ru>
* Copyright (C) 2017, 2019 B00mX0r <b00mx0r@aureus.pw>
* Copyright (C) 2017 Sheogorath <sheogorath@shivering-isles.com>
* Copyright (C) 2016 Adam <Adam@anope.org>
* Copyright (C) 2014 Thomas Fargeix <t.fargeix@gmail.com>
* Copyright (C) 2013, 2018 Attila Molnar <attilamolnar@hush.com>
* Copyright (C) 2013, 2016-2021 Sadie Powell <sadie@witchery.services>
* Copyright (C) 2012 Robby <robby@chatbelgie.be>
* Copyright (C) 2011 jackmcbarn <jackmcbarn@inspircd.org>
* Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
* Copyright (C) 2007-2009 Robin Burchell <robin+git@viroteck.net>
* Copyright (C) 2007-2008 Dennis Friis <peavey@inspircd.org>
* Copyright (C) 2007 John Brooks <special@inspircd.org>
* Copyright (C) 2006 Oliver Lupton <om@inspircd.org>
* Copyright (C) 2003, 2007-2008, 2010 Craig Edwards <brain@inspircd.org>
*
* 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 "modules/hash.h"
enum CloakMode
{
/** 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";
// The minimum length of a cloak key.
static const size_t minkeylen = 30;
struct CloakInfo
{
// The method used for cloaking users.
CloakMode mode;
// The number of parts of the hostname shown when using half cloaking.
unsigned int domainparts;
// Whether to ignore the case of a hostname when cloaking it.
bool ignorecase;
// The secret used for generating cloaks.
std::string key;
// The prefix for cloaks (e.g. MyNet-).
std::string prefix;
// The suffix for IP cloaks (e.g. .IP).
std::string suffix;
CloakInfo(CloakMode Mode, const std::string& Key, const std::string& Prefix, const std::string& Suffix, bool IgnoreCase, unsigned int DomainParts = 0)
: mode(Mode)
, domainparts(DomainParts)
, ignorecase(IgnoreCase)
, key(Key)
, prefix(Prefix)
, suffix(Suffix)
{
}
};
typedef std::vector<std::string> CloakList;
class CloakExtItem : public SimpleExtItem<CloakList>
{
public:
CloakExtItem(Module* Creator)
: SimpleExtItem("cloaks", ExtensionItem::EXT_USER, Creator)
{
}
std::string ToHuman(const Extensible* container, void* item) const CXX11_OVERRIDE
{
return stdalgo::string::join(*static_cast<CloakList*>(item), ' ');
}
};
class CloakUser : public ModeHandler
{
public:
bool active;
CloakExtItem ext;
std::string debounce_uid;
time_t debounce_ts;
int debounce_count;
CloakUser(Module* source)
: ModeHandler(source, "cloak", 'x', PARAM_NONE, MODETYPE_USER)
, active(false)
, ext(source)
, debounce_ts(0)
, debounce_count(0)
{
}
ModeAction OnModeChange(User* source, User* dest, Channel* channel, std::string& parameter, bool adding) CXX11_OVERRIDE
{
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)
{
// Remote setters broadcast mode before host while local setters do the opposite, so this takes that into account
active = IS_LOCAL(source) ? adding : !adding;
dest->SetMode(this, 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(this))
return MODEACTION_DENY;
/* don't allow this user to spam modechanges */
if (source == dest)
user->CommandFloodPenalty += 5000;
if (adding)
{
// assume this is more correct
if (user->registered != REG_ALL && user->GetRealHost() != user->GetDisplayedHost())
return MODEACTION_DENY;
CloakList* cloaks = ext.get(user);
if (!cloaks)
{
/* Force creation of missing cloak */
try
{
creator->OnUserConnect(user);
cloaks = ext.get(user);
}
catch (CoreException& modexcept)
{
ServerInstance->Logs->Log(MODNAME, LOG_DEFAULT, "Exception caught when generating cloak: " + modexcept.GetReason());
return MODEACTION_DENY;
}
}
// If we have a cloak then set the hostname.
if (cloaks && !cloaks->empty())
{
user->ChangeDisplayedHost(cloaks->front());
user->SetMode(this, 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(this, false);
user->ChangeDisplayedHost(user->GetRealHost());
return MODEACTION_ALLOW;
}
}
};
class CommandCloak : public Command
{
public:
CommandCloak(Module* Creator) : Command(Creator, "CLOAK", 1)
{
flags_needed = 'o';
syntax = "<host>";
}
CmdResult Handle(User* user, const Params& parameters) CXX11_OVERRIDE;
};
class ModuleCloaking : public Module
{
public:
CloakUser cu;
CommandCloak ck;
std::vector<CloakInfo> cloaks;
dynamic_reference<HashProvider> Hash;
ModuleCloaking()
: cu(this)
, ck(this)
, Hash(this, "hash/md5")
{
}
/** Takes a domain name and retrieves the subdomain which should be visible.
* This is usually the last \p domainparts labels but if not enough are
* present then all but the most specific label are used. If the domain name
* consists of one label only then none are used.
*
* Here are some examples for how domain names will be shortened assuming
* \p domainparts is set to the default of 3.
*
* "this.is.an.example.com" => ".an.example.com"
* "an.example.com" => ".example.com"
* "example.com" => ".com"
* "localhost" => ""
*
* @param host The hostname to cloak.
* @param domainparts The number of domain labels that should be visible.
* @return The visible segment of the hostname.
*/
std::string VisibleDomainParts(const std::string& host, unsigned int domainparts)
{
// The position at which we found the last dot.
std::string::const_reverse_iterator dotpos;
// The number of dots we have seen so far.
unsigned int seendots = 0;
for (std::string::const_reverse_iterator iter = host.rbegin(); iter != host.rend(); ++iter)
{
if (*iter != '.')
continue;
// We have found a dot!
dotpos = iter;
seendots += 1;
// Do we have enough segments to stop?
if (seendots >= domainparts)
break;
}
// We only returns a domain part if more than one label is
// present. See above for a full explanation.
if (!seendots)
return "";
return std::string(dotpos.base() - 1, host.end());
}
/**
* 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 CloakInfo& info, const std::string& item, char id, size_t len)
{
std::string input;
input.reserve(info.key.length() + 3 + item.length());
input.append(1, id);
input.append(info.key);
input.append(1, '\0'); // null does not terminate a C++ string
if (info.ignorecase)
std::transform(item.begin(), item.end(), std::back_inserter(input), ::tolower);
else
input.append(item);
std::string rv = Hash->GenerateRaw(input).substr(0,len);
for(size_t 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 SegmentIP(const CloakInfo& info, const irc::sockets::sockaddrs& ip, bool full)
{
std::string bindata;
size_t hop1, hop2, hop3;
size_t len1, len2;
std::string rv;
if (ip.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(info.prefix.length() + 26 + info.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(info.prefix.length() + 15 + info.suffix.length());
}
rv.append(info.prefix);
rv.append(SegmentCloak(info, bindata, 10, len1));
rv.append(1, '.');
bindata.erase(hop1);
rv.append(SegmentCloak(info, bindata, 11, len2));
if (hop2)
{
rv.append(1, '.');
bindata.erase(hop2);
rv.append(SegmentCloak(info, bindata, 12, len2));
}
if (full)
{
rv.append(1, '.');
bindata.erase(hop3);
rv.append(SegmentCloak(info, bindata, 13, 6));
rv.append(info.suffix);
}
else
{
if (ip.family() == AF_INET6)
{
rv.append(InspIRCd::Format(".%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], info.suffix.c_str()));
}
else
{
const unsigned char* ip4 = (const unsigned char*)&ip.in4.sin_addr;
rv.append(InspIRCd::Format(".%d.%d%s", ip4[1], ip4[0], info.suffix.c_str()));
}
}
return rv;
}
ModResult OnCheckBan(User* user, Channel* chan, const std::string& mask) CXX11_OVERRIDE
{
LocalUser* lu = IS_LOCAL(user);
if (!lu)
return MOD_RES_PASSTHRU;
// Force the creation of cloaks if not already set.
OnUserConnect(lu);
// If the user has no cloaks (i.e. UNIX socket) then we do nothing here.
CloakList* cloaklist = cu.ext.get(user);
if (!cloaklist || cloaklist->empty())
return MOD_RES_PASSTHRU;
// Check if they have a cloaked host but are not using it.
for (CloakList::const_iterator iter = cloaklist->begin(); iter != cloaklist->end(); ++iter)
{
const std::string& cloak = *iter;
if (cloak != user->GetDisplayedHost())
{
const std::string cloakMask = user->nick + "!" + user->ident + "@" + cloak;
if (InspIRCd::Match(cloakMask, mask))
return MOD_RES_DENY;
}
}
return MOD_RES_PASSTHRU;
}
void Prioritize() CXX11_OVERRIDE
{
/* 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) CXX11_OVERRIDE
{
if (u->IsModeSet(cu) && !cu.active)
{
u->SetMode(cu, false);
LocalUser* luser = IS_LOCAL(u);
if (!luser)
return;
Modes::ChangeList modechangelist;
modechangelist.push_remove(&cu);
ClientProtocol::Events::Mode modeevent(ServerInstance->FakeClient, NULL, u, modechangelist);
luser->Send(modeevent);
}
cu.active = false;
}
Version GetVersion() CXX11_OVERRIDE
{
std::string testcloak = "broken";
if (Hash && !cloaks.empty())
{
const CloakInfo& info = cloaks.front();
switch (info.mode)
{
case MODE_HALF_CLOAK:
// Use old cloaking verification to stay compatible with 2.0
// But verify domainparts and ignorecase when use 3.0-only features
if (info.domainparts == 3 && !info.ignorecase)
testcloak = info.prefix + SegmentCloak(info, "*", 3, 8) + info.suffix;
else
{
irc::sockets::sockaddrs sa;
testcloak = GenCloak(info, sa, "", testcloak + ConvToStr(info.domainparts)) + (info.ignorecase ? "-ci" : "");
}
break;
case MODE_OPAQUE:
testcloak = info.prefix + SegmentCloak(info, "*", 4, 8) + info.suffix + (info.ignorecase ? "-ci" : "");
}
}
return Version("Adds user mode x (cloak) which allows user hostnames to be hidden.", VF_COMMON|VF_VENDOR, testcloak);
}
void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
{
ConfigTagList tags = ServerInstance->Config->ConfTags("cloak");
if (tags.first == tags.second)
throw ModuleException("You have loaded the cloaking module but not configured any <cloak> tags!");
std::vector<CloakInfo> newcloaks;
for (ConfigIter i = tags.first; i != tags.second; ++i)
{
ConfigTag* tag = i->second;
// Ensure that we have the <cloak:key> parameter.
const std::string key = tag->getString("key");
if (key.empty())
throw ModuleException("You have not defined a cloaking key. Define <cloak:key> as a " + ConvToStr(minkeylen) + "+ character network-wide secret, at " + tag->getTagLocation());
// If we are the first cloak method then mandate a strong key.
if (i == tags.first && key.length() < minkeylen)
throw ModuleException("Your cloaking key is not secure. It should be at least " + ConvToStr(minkeylen) + " characters long, at " + tag->getTagLocation());
const bool ignorecase = tag->getBool("ignorecase");
const std::string mode = tag->getString("mode");
const std::string prefix = tag->getString("prefix");
const std::string suffix = tag->getString("suffix", ".IP");
if (stdalgo::string::equalsci(mode, "half"))
{
unsigned int domainparts = tag->getUInt("domainparts", 3, 1, 10);
newcloaks.push_back(CloakInfo(MODE_HALF_CLOAK, key, prefix, suffix, ignorecase, domainparts));
}
else if (stdalgo::string::equalsci(mode, "full"))
newcloaks.push_back(CloakInfo(MODE_OPAQUE, key, prefix, suffix, ignorecase));
else
throw ModuleException(mode + " is an invalid value for <cloak:mode>; acceptable values are 'half' and 'full', at " + tag->getTagLocation());
}
// The cloak configuration was valid so we can apply it.
cloaks.swap(newcloaks);
}
std::string GenCloak(const CloakInfo& info, const irc::sockets::sockaddrs& ip, const std::string& ipstr, const std::string& host)
{
std::string chost;
irc::sockets::sockaddrs hostip;
bool host_is_ip = irc::sockets::aptosa(host, ip.port(), hostip) && hostip == ip;
switch (info.mode)
{
case MODE_HALF_CLOAK:
{
if (!host_is_ip)
chost = info.prefix + SegmentCloak(info, host, 1, 6) + VisibleDomainParts(host, info.domainparts);
if (chost.empty() || chost.length() > 50)
chost = SegmentIP(info, ip, false);
break;
}
case MODE_OPAQUE:
default:
chost = SegmentIP(info, ip, true);
}
return chost;
}
void OnSetUserIP(LocalUser* user) CXX11_OVERRIDE
{
// Connecting users are handled in OnUserConnect not here.
if (user->registered != REG_ALL || user->quitting)
return;
// Remove the cloaks and generate new ones.
cu.ext.unset(user);
OnUserConnect(user);
// If a user is using a cloak then update it.
if (user->IsModeSet(cu))
{
CloakList* cloaklist = cu.ext.get(user);
user->ChangeDisplayedHost(cloaklist->front());
}
}
void OnUserConnect(LocalUser* dest) CXX11_OVERRIDE
{
if (cu.ext.get(dest))
return;
// TODO: decide how we are going to cloak AF_UNIX hostnames.
if (dest->client_sa.family() != AF_INET && dest->client_sa.family() != AF_INET6)
return;
CloakList cloaklist;
for (std::vector<CloakInfo>::const_iterator iter = cloaks.begin(); iter != cloaks.end(); ++iter)
cloaklist.push_back(GenCloak(*iter, dest->client_sa, dest->GetIPString(), dest->GetRealHost()));
cu.ext.set(dest, cloaklist);
}
};
CmdResult CommandCloak::Handle(User* user, const Params& parameters)
{
ModuleCloaking* mod = (ModuleCloaking*)(Module*)creator;
// If we're cloaking an IP address we pass it in the IP field too.
irc::sockets::sockaddrs sa;
const char* ipaddr = irc::sockets::aptosa(parameters[0], 0, sa) ? parameters[0].c_str() : "";
unsigned int id = 0;
for (std::vector<CloakInfo>::const_iterator iter = mod->cloaks.begin(); iter != mod->cloaks.end(); ++iter)
{
const std::string cloak = mod->GenCloak(*iter, sa, ipaddr, parameters[0]);
user->WriteNotice(InspIRCd::Format("*** Cloak #%u for %s is %s", ++id, parameters[0].c_str(), cloak.c_str()));
}
return CMD_SUCCESS;
}
MODULE_INIT(ModuleCloaking)
