/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2019 B00mX0r <b00mx0r@aureus.pw>
* Copyright (C) 2017 Sheogorath <sheogorath@shivering-isles.com>
* Copyright (C) 2016 Adam <Adam@anope.org>
* Copyright (C) 2013, 2017-2019, 2021-2023 Sadie Powell <sadie@witchery.services>
* Copyright (C) 2012 Robby <robby@chatbelgie.be>
* Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
* Copyright (C) 2008 Robin Burchell <robin+git@viroteck.net>
* Copyright (C) 2007-2008 Craig Edwards <brain@inspircd.org>
* Copyright (C) 2007 John Brooks <special@inspircd.org>
* Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
* Copyright (C) 2006 Oliver Lupton <om@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/cloak.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 constexpr char base32[] = "0123456789abcdefghijklmnopqrstuv";
// The minimum length of a cloak key.
static constexpr size_t minkeylen = 30;
struct CloakInfo final
: public Cloak::Method
{
// 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;
// Dynamic reference to the md5 implementation.
dynamic_reference_nocheck<HashProvider> md5;
// The prefix for cloaks (e.g. MyNet-).
std::string prefix;
// The suffix for IP cloaks (e.g. .IP).
std::string suffix;
CloakInfo(const Cloak::Engine* engine, const std::shared_ptr<ConfigTag>& tag, CloakMode Mode, const std::string& Key)
: Cloak::Method(engine, tag)
, mode(Mode)
, domainparts(tag->getNum<unsigned int>("domainparts", 3, 1, 10))
, ignorecase(tag->getBool("ignorecase"))
, key(Key)
, md5(engine->creator, "hash/md5")
, prefix(tag->getString("prefix"))
, suffix(tag->getString("suffix", ".IP"))
{
}
/*
* 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, size_t 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
if (ignorecase)
std::transform(item.begin(), item.end(), std::back_inserter(input), ::tolower);
else
input.append(item);
std::string rv = md5->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 irc::sockets::sockaddrs& ip, bool full)
{
std::string bindata;
size_t hop1;
size_t hop2;
size_t hop3;
size_t len1;
size_t 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(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
{
if (ip.family() == AF_INET6)
{
rv.append(INSP_FORMAT(".{:02x}{:02x}.{:02x}{:02x}{}",
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));
}
else
{
const unsigned char* ip4 = (const unsigned char*)&ip.in4.sin_addr;
rv.append(INSP_FORMAT(".{}.{}{}", ip4[1], ip4[0], suffix));
}
}
return rv;
}
std::string GetCompatLinkData()
{
std::string data = "broken";
if (md5)
{
switch (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 (domainparts == 3 && !ignorecase)
data = prefix + SegmentCloak("*", 3, 8) + suffix;
else
{
irc::sockets::sockaddrs sa;
data = GenCloak(sa, "", data + ConvToStr(domainparts)) + (ignorecase ? "-ci" : "");
}
break;
case MODE_OPAQUE:
data = prefix + SegmentCloak("*", 4, 8) + suffix + (ignorecase ? "-ci" : "");
}
}
return data;
}
void GetLinkData(Module::LinkData& data, std::string& compatdata) override
{
data["domain-parts"] = ConvToStr(domainparts);
data["ignore-case"] = ignorecase ? "yes" : "no";
data["prefix"] = prefix;
data["suffix"] = suffix;
// IMPORTANT: link data is sent over unauthenticated server links so we
// can't directly send the key here. Instead we use dummy cloaks that
// allow verification of or less the same thing.
const std::string broken = "missing-md5-module";
data["cloak-v4"] = md5 ? Generate("123.123.123.123") : broken;
data["cloak-v6"] = md5 ? Generate("dead:beef:cafe::") : broken;
data["cloak-host"] = md5 ? Generate("extremely.long.inspircd.cloak.example") : broken;
compatdata = GetCompatLinkData();
}
bool IsLinkSensitive() const override
{
// This method always wants to be at the front.
return true;
}
std::string GenCloak(const irc::sockets::sockaddrs& ip, const std::string& ipstr, const std::string& host)
{
std::string chost;
irc::sockets::sockaddrs hostip(false);
bool host_is_ip = hostip.from_ip_port(host, ip.port()) && hostip == ip;
switch (mode)
{
case MODE_HALF_CLOAK:
{
if (!host_is_ip)
chost = prefix + SegmentCloak(host, 1, 6) + "." + Cloak::VisiblePart(host, domainparts, '.');
if (chost.empty() || chost.length() > 50)
chost = SegmentIP(ip, false);
break;
}
case MODE_OPAQUE:
chost = SegmentIP(ip, true);
break;
}
return chost;
}
std::string Generate(LocalUser* user) override ATTR_NOT_NULL(2)
{
if (!md5 || !user->client_sa.is_ip() || !MatchesUser(user))
return {};
return GenCloak(user->client_sa, user->GetAddress(), user->GetRealHost());
}
std::string Generate(const std::string& hostip) override
{
if (!md5)
return {};
irc::sockets::sockaddrs sa;
const char* ipaddr = sa.from_ip(hostip) ? hostip.c_str() : "";
return GenCloak(sa, ipaddr, hostip);
}
};
class MD5Engine final
: public Cloak::Engine
{
private:
// Dynamic reference to the md5 implementation.
dynamic_reference_nocheck<HashProvider> md5;
// The method used for cloaking users.
CloakMode mode;
public:
MD5Engine(Module* Creator, const std::string& Name, CloakMode cm)
: Cloak::Engine(Creator, Name)
, md5(Creator, "hash/md5")
, mode(cm)
{
}
Cloak::MethodPtr Create(const std::shared_ptr<ConfigTag>& tag, bool primary) override
{
// Check any dependent modules are loaded.
if (!md5)
throw ModuleException(creator, "Unable to create a " + name.substr(6) + " cloak without the md5 module, at" + tag->source.str());
// Ensure that we have the <cloak:key> parameter.
const std::string key = tag->getString("key");
if (key.empty())
throw ModuleException(creator, "You have not defined a cloaking key. Define <cloak:key> as a " + ConvToStr(minkeylen) + "+ character network-wide secret, at " + tag->source.str());
// If we are the first cloak method then mandate a strong key.
if (primary && key.length() < minkeylen)
throw ModuleException(creator, "Your cloaking key is not secure. It should be at least " + ConvToStr(minkeylen) + " characters long, at " + tag->source.str());
return std::make_shared<CloakInfo>(this, tag, mode, key);
}
};
class ModuleCloakMD5 final
: public Module
{
private:
MD5Engine halfcloak;
MD5Engine fullcloak;
public:
ModuleCloakMD5()
: Module(VF_VENDOR, "Adds the half and full cloaking methods for use with the cloak module.")
, halfcloak(this, "half", MODE_HALF_CLOAK)
, fullcloak(this, "full", MODE_OPAQUE)
{
}
};
MODULE_INIT(ModuleCloakMD5)
