/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2021 Dominic Hamon
* Copyright (C) 2017-2024 Sadie Powell <sadie@witchery.services>
* Copyright (C) 2014 md_5 <git@md-5.net>
* Copyright (C) 2014 Googolplexed <googol@googolplexed.net>
* Copyright (C) 2012 Robby <robby@chatbelgie.be>
* Copyright (C) 2012 Attila Molnar <attilamolnar@hush.com>
* Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
* Copyright (C) 2009 Uli Schlachter <psychon@znc.in>
* Copyright (C) 2008 Robin Burchell <robin+git@viroteck.net>
* Copyright (C) 2006-2007, 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 "extension.h"
#include "modules/extban.h"
#include "modules/hash.h"
#include "modules/ssl.h"
#include "modules/webirc.h"
#include "modules/whois.h"
// One or more hostmask globs or CIDR ranges.
typedef std::vector<std::string> MaskList;
// Encapsulates information about a username gateway.
class UserHost final
{
private:
MaskList hostmasks;
std::string newuser;
public:
UserHost(const MaskList& masks, const std::string& user)
: hostmasks(masks)
, newuser(user)
{
}
const std::string& GetUser() const
{
return newuser;
}
bool Matches(LocalUser* user) const
{
for (const auto& mask : hostmasks)
{
// Does the user's hostname match this hostmask?
if (InspIRCd::Match(user->GetRealHost(), mask, ascii_case_insensitive_map))
return true;
// Does the user's IP address match this hostmask?
if (InspIRCd::MatchCIDR(user->GetAddress(), mask, ascii_case_insensitive_map))
return true;
}
// The user didn't match any hostmasks.
return false;
}
};
// Encapsulates information about a WebIRC gateway.
class WebIRCHost final
{
private:
MaskList hostmasks;
std::string fingerprint;
std::string password;
std::string passhash;
TokenList trustedflags;
public:
WebIRCHost(const MaskList& masks, const std::string& fp, const std::string& pass, const std::string& hash, const std::string& flags)
: hostmasks(masks)
, fingerprint(fp)
, password(pass)
, passhash(hash)
, trustedflags(flags)
{
}
bool IsFlagTrusted(const std::string& flag) const
{
return trustedflags.Contains(flag);
}
bool Matches(LocalUser* user, const std::string& pass, UserCertificateAPI& sslapi) const
{
// Did the user send a valid password?
if (!password.empty() && !Hash::CheckPassword(password, passhash, pass))
return false;
// Does the user have a valid fingerprint?
if (!fingerprint.empty())
{
if (!sslapi)
return false;
bool okay = false;
for (const auto& fp : sslapi->GetFingerprints(user))
{
if (InspIRCd::TimingSafeCompare(fp, fingerprint))
{
okay = true;
break;
}
}
if (!okay)
return false;
}
for (const auto& mask : hostmasks)
{
// Does the user's hostname match this hostmask?
if (InspIRCd::Match(user->GetRealHost(), mask, ascii_case_insensitive_map))
return true;
// Does the user's IP address match this hostmask?
if (InspIRCd::MatchCIDR(user->GetAddress(), mask, ascii_case_insensitive_map))
return true;
}
// The user didn't match any hostmasks.
return false;
}
};
class CommandHexIP final
: public SplitCommand
{
public:
CommandHexIP(Module* Creator)
: SplitCommand(Creator, "HEXIP", 1)
{
penalty = 2000;
syntax = { "<hex-ip|raw-ip>" };
}
CmdResult HandleLocal(LocalUser* user, const Params& parameters) override
{
irc::sockets::sockaddrs sa(false);
if (sa.from_ip(parameters[0]))
{
if (sa.family() != AF_INET)
{
user->WriteNotice("*** HEXIP: You can only hex encode an IPv4 address!");
return CmdResult::FAILURE;
}
uint32_t addr = sa.in4.sin_addr.s_addr;
user->WriteNotice("*** HEXIP: {} encodes to {:02x}{:02x}{:02x}{:02x}.",
sa.addr(), (addr & 0xFF), ((addr >> 8) & 0xFF), ((addr >> 16) & 0xFF),
((addr >> 24) & 0xFF));
return CmdResult::SUCCESS;
}
if (ParseIP(parameters[0], sa))
{
user->WriteNotice("*** HEXIP: {} decodes to {}.", parameters[0], sa.addr());
return CmdResult::SUCCESS;
}
user->WriteNotice("*** HEXIP: {} is not a valid raw or hex encoded IPv4 address.",
parameters[0]);
return CmdResult::FAILURE;
}
static bool ParseIP(const std::string& in, irc::sockets::sockaddrs& out)
{
const char* username = nullptr;
if (in.length() == 8)
{
// The username is an IPv4 address encoded in hexadecimal with two characters
// per address segment.
username = in.c_str();
}
else if (in.length() == 9 && in[0] == '~')
{
// The same as above but m_ident got to this user before we did. Strip the
// username prefix and continue as normal.
username = in.c_str() + 1;
}
else
{
// The user either does not have an IPv4 in their username or the gateway server
// is also running an identd. In the latter case there isn't really a lot we
// can do so we just assume that the client in question is not connecting via
// a username gateway.
return false;
}
// Try to convert the IP address to a string. If this fails then the user
// does not have an IPv4 address in their username.
errno = 0;
unsigned long address = strtoul(username, nullptr, 16);
if (errno)
return false;
// If the converted IP address is > 32 bits then it's not valid so bail.
if (address > UINT32_MAX)
return false;
out.in4.sin_family = AF_INET;
out.in4.sin_addr.s_addr = htonl(uint32_t(address));
return true;
}
};
class GatewayExtBan final
: public ExtBan::MatchingBase
{
public:
StringExtItem gateway;
GatewayExtBan(Module* Creator)
: ExtBan::MatchingBase(Creator, "gateway", 'w')
, gateway(Creator, "webirc-gateway", ExtensionType::USER, true)
{
}
bool IsMatch(User* user, Channel* channel, const std::string& text, bool full) override
{
const std::string* gatewayname = gateway.Get(user);
return gatewayname ? InspIRCd::Match(*gatewayname, text) : false;
}
};
class CommandWebIRC final
: public SplitCommand
{
public:
std::vector<WebIRCHost> hosts;
GatewayExtBan extban;
StringExtItem realhost;
StringExtItem realip;
UserCertificateAPI sslapi;
Events::ModuleEventProvider webircevprov;
CommandWebIRC(Module* Creator)
: SplitCommand(Creator, "WEBIRC", 4)
, extban(Creator)
, realhost(Creator, "gateway-realhost", ExtensionType::USER, true)
, realip(Creator, "gateway-realip", ExtensionType::USER, true)
, sslapi(Creator)
, webircevprov(Creator, "event/webirc")
{
works_before_reg = true;
syntax = { "<password> <gateway> <hostname> <ip> [<flags>]" };
}
CmdResult HandleLocal(LocalUser* user, const Params& parameters) override
{
if (user->IsFullyConnected() || realhost.Get(user))
return CmdResult::FAILURE;
for (const auto& host : hosts)
{
// If we don't match the host then skip to the next host.
if (!host.Matches(user, parameters[0], sslapi))
continue;
irc::sockets::sockaddrs ipaddr(false);
if (!ipaddr.from_ip_port(parameters[3], user->client_sa.port()))
{
ServerInstance->SNO.WriteGlobalSno('w', "Connecting user {} ({}) tried to use WEBIRC but gave an invalid IP address.",
user->uuid, user->GetAddress());
ServerInstance->Users.QuitUser(user, "WEBIRC: IP address is invalid: " + parameters[3]);
return CmdResult::FAILURE;
}
// The user matched a WebIRC block!
extban.gateway.Set(user, parameters[1]);
realhost.Set(user, user->GetRealHost());
realip.Set(user, user->GetAddress());
ServerInstance->SNO.WriteGlobalSno('w', "Connecting user {} is using the {} WebIRC gateway; changing their IP from {} to {}.",
user->uuid, parameters[1], user->GetAddress(), parameters[3]);
// If we have custom flags then deal with them.
WebIRC::FlagMap flags;
const bool hasflags = (parameters.size() > 4);
if (hasflags)
{
std::string flagname;
std::string flagvalue;
// Parse the flags.
irc::spacesepstream flagstream(parameters[4]);
for (std::string flag; flagstream.GetToken(flag); )
{
// Does this flag have a value?
const size_t separator = flag.find('=');
if (separator == std::string::npos)
{
// It does not; just use the flag.
flagname = flag;
flagvalue.clear();
}
else
{
// It does; extract the value.
flagname = flag.substr(0, separator);
flagvalue = flag.substr(separator + 1);
}
if (host.IsFlagTrusted(flagname))
flags[flagname] = flagvalue;
}
}
// Inform modules about the WebIRC attempt.
webircevprov.Call(&WebIRC::EventListener::OnWebIRCAuth, user, (hasflags ? &flags : nullptr));
// Set the IP address sent via WEBIRC. We ignore the hostname and lookup
// instead do our own DNS lookups because of unreliable gateways.
user->ChangeRemoteAddress(ipaddr);
return CmdResult::SUCCESS;
}
ServerInstance->SNO.WriteGlobalSno('w', "Connecting user {} ({}) tried to use WEBIRC but didn't match any configured WebIRC hosts.",
user->uuid, user->GetAddress());
ServerInstance->Users.QuitUser(user, "WEBIRC: you don't match any configured WebIRC hosts.");
return CmdResult::FAILURE;
}
};
class ModuleGateway final
: public Module
, public WebIRC::EventListener
, public Whois::EventListener
{
private:
CommandHexIP cmdhexip;
CommandWebIRC cmdwebirc;
std::vector<UserHost> hosts;
public:
ModuleGateway()
: Module(VF_VENDOR, "Adds the ability for IRC gateways to forward the real IP address of users connecting through them.")
, WebIRC::EventListener(this)
, Whois::EventListener(this)
, cmdhexip(this)
, cmdwebirc(this)
{
}
void init() override
{
ServerInstance->SNO.EnableSnomask('w', "GATEWAY");
}
void ReadConfig(ConfigStatus& status) override
{
std::vector<UserHost> userhosts;
std::vector<WebIRCHost> webirchosts;
for (const auto& [_, tag] : ServerInstance->Config->ConfTags("gateway", ServerInstance->Config->ConfTags("cgihost")))
{
MaskList masks;
irc::spacesepstream maskstream(tag->getString("mask"));
for (std::string mask; maskstream.GetToken(mask); )
masks.push_back(mask);
// Ensure that we have the <gateway:mask> parameter.
if (masks.empty())
throw ModuleException(this, "<" + tag->name + ":mask> is a mandatory field, at " + tag->source.str());
// Determine what lookup type this host uses.
const std::string type = tag->getString("type");
if (insp::equalsci(type, "username") || insp::equalsci(type, "ident"))
{
// The IP address should be looked up from the hex IP address.
const std::string newuser = tag->getString("newusername", "gateway", ServerInstance->Users.IsUser);
userhosts.emplace_back(masks, newuser);
}
else if (insp::equalsci(type, "webirc"))
{
// The IP address will be received via the WEBIRC command.
const std::string fingerprint = tag->getString("fingerprint");
const std::string password = tag->getString("password");
const std::string passwordhash = tag->getString("hash", "plaintext", 1);
const std::string trustedflags = tag->getString("trustedflags", "*", 1);
// WebIRC blocks require a password.
if (fingerprint.empty() && password.empty())
throw ModuleException(this, "When using <" + tag->name + " type=\"webirc\"> either the fingerprint or password field is required, at " + tag->source.str());
if (!password.empty() && insp::equalsci(passwordhash, "plaintext"))
{
ServerInstance->Logs.Normal(MODNAME, "<{}> tag at {} contains an plain text password, this is insecure!",
tag->name, tag->source.str());
}
webirchosts.emplace_back(masks, fingerprint, password, passwordhash, trustedflags);
}
else
{
throw ModuleException(this, type + " is an invalid <" + tag->name + ":mask> type, at " + tag->source.str());
}
}
// The host configuration was valid so we can apply it.
hosts.swap(userhosts);
cmdwebirc.hosts.swap(webirchosts);
}
ModResult OnPreChangeConnectClass(LocalUser* user, const std::shared_ptr<ConnectClass>& klass, std::optional<Numeric::Numeric>& errnum) override
{
// If <connect:webirc> is not set then we have nothing to do.
const std::string webirc = klass->config->getString("webirc");
if (webirc.empty())
return MOD_RES_PASSTHRU;
// If the user is not connecting via a WebIRC gateway then they
// cannot match this connect class.
const std::string* gateway = cmdwebirc.extban.gateway.Get(user);
if (!gateway)
{
ServerInstance->Logs.Debug("CONNECTCLASS", "The {} connect class is not suitable as it requires a connection via a WebIRC gateway.",
klass->GetName());
return MOD_RES_DENY;
}
// If the gateway matches the <connect:webirc> constraint then
// allow the check to continue. Otherwise, reject it.
if (!InspIRCd::Match(*gateway, webirc))
{
ServerInstance->Logs.Debug("CONNECTCLASS", "The {} connect class is not suitable as the WebIRC gateway name ({}) does not match {}.",
klass->GetName(), *gateway, webirc);
return MOD_RES_DENY;
}
return MOD_RES_PASSTHRU;
}
ModResult OnUserRegister(LocalUser* user) override
{
// There is no need to check for gateways if one is already being used.
if (cmdwebirc.realhost.Get(user))
return MOD_RES_PASSTHRU;
for (const auto& host : hosts)
{
// If we don't match the host then skip to the next host.
if (!host.Matches(user))
continue;
// We have matched an gateway block! Try to parse the encoded IPv4 address
// out of the user.
irc::sockets::sockaddrs address(user->client_sa);
if (!CommandHexIP::ParseIP(user->GetRealUser(), address))
return MOD_RES_PASSTHRU;
// Store the hostname and IP of the gateway for later use.
cmdwebirc.realhost.Set(user, user->GetRealHost());
cmdwebirc.realip.Set(user, user->GetAddress());
const std::string& newuser = host.GetUser();
ServerInstance->SNO.WriteGlobalSno('w', "Connecting user {} is using a username gateway; changing their IP from {} to {} and their real username from {} to {}.",
user->uuid, user->GetAddress(), address.addr(), user->GetRealUser(), newuser);
user->ChangeRealUser(newuser, user->GetDisplayedUser() == user->GetRealUser());
user->ChangeRemoteAddress(address);
break;
}
return MOD_RES_PASSTHRU;
}
void OnWebIRCAuth(LocalUser* user, const WebIRC::FlagMap* flags) override
{
// We are only interested in connection flags. If none have been
// given then we have nothing to do.
if (!flags)
return;
WebIRC::FlagMap::const_iterator cport = flags->find("remote-port");
if (cport != flags->end())
{
// If we can't parse the port then just give up.
in_port_t port = ConvToNum<in_port_t>(cport->second);
if (port)
{
switch (user->client_sa.family())
{
case AF_INET:
user->client_sa.in4.sin_port = htons(port);
break;
case AF_INET6:
user->client_sa.in6.sin6_port = htons(port);
break;
default:
// If we have reached this point then we have encountered a bug.
ServerInstance->Logs.Debug(MODNAME, "BUG: OnWebIRCAuth({}): socket type {} is unknown!",
user->uuid, user->client_sa.family());
return;
}
}
}
WebIRC::FlagMap::const_iterator sport = flags->find("local-port");
if (sport != flags->end())
{
// If we can't parse the port then just give up.
in_port_t port = ConvToNum<in_port_t>(sport->second);
if (port)
{
switch (user->server_sa.family())
{
case AF_INET:
user->server_sa.in4.sin_port = htons(port);
break;
case AF_INET6:
user->server_sa.in6.sin6_port = htons(port);
break;
default:
// If we have reached this point then we have encountered a bug.
ServerInstance->Logs.Debug(MODNAME, "BUG: OnWebIRCAuth({}): socket type {} is unknown!",
user->uuid, user->server_sa.family());
return;
}
}
}
}
void OnWhois(Whois::Context& whois) override
{
// If these fields are not set then the client is not using a gateway.
std::string* realhost = cmdwebirc.realhost.Get(whois.GetTarget());
std::string* realip = cmdwebirc.realip.Get(whois.GetTarget());
if (!realhost || !realip)
return;
// If the source doesn't have the right privs then only show the gateway name.
std::string hidden = "*";
if (!whois.GetSource()->HasPrivPermission("users/auspex"))
realhost = realip = &hidden;
const std::string* gateway = cmdwebirc.extban.gateway.Get(whois.GetTarget());
if (gateway)
whois.SendLine(RPL_WHOISGATEWAY, *realhost, *realip, "is connected via the " + *gateway + " WebIRC gateway");
else
whois.SendLine(RPL_WHOISGATEWAY, *realhost, *realip, "is connected via a username gateway");
}
};
MODULE_INIT(ModuleGateway)
