Shuffle the modules about a bit.

1 files changed, 566 insertions, 0 deletions

diff --git a/modules/gateway.cpp b/modules/gateway.cpp
new file mode 100644
index 000000000..00d2b7cfb
--- /dev/null
+++ b/modules/gateway.cpp
@@ -0,0 +1,566 @@
+/*
+ * 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) 2007-2009 Robin Burchell <robin+git@viroteck.net>
+ *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
+ *   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/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() && !InspIRCd::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(fmt::format("*** 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(fmt::format("*** HEXIP: {} decodes to {}.", parameters[0], sa.addr()));
+			return CmdResult::SUCCESS;
+		}
+
+		user->WriteNotice(fmt::format("*** 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) 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->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)