Add the m_ircv3_sts module which implements the IRCv3 STS spec.

docs/conf/modules.conf.example

@@ -1013,6 +1013,27 @@
 # another user into a channel. This respects <options:announceinvites>.
 #<module name="ircv3_invitenotify">
 
+#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
+# IRCv3 Strict Transport Security module: Provides the sts IRCv3.2
+# extension which allows clients connecting insecurely to upgrade their
+# connections to TLS.
+#<module name="ircv3_sts">
+#
+# If using the ircv3_sts module you MUST define a STS policy to send
+# to clients using the <sts> tag. This tag takes the following
+# attributes:
+#
+# host     - A glob match for the SNI hostname to apply this policy to.
+# duration - The amount of time that the policy lasts for. Defaults to
+#            approximately two months by default.
+# port     - The port on which TLS connections to the server are being
+#            accepted. You MUST have a CA-verified certificate on this
+#            port. Self signed certificates are not acceptable.
+# preload  - Whether client developers can include your certificate in
+#            preload lists.
+#
+# <sts host="*.example.com" duration="60d" port="6697" preload="yes">
+
 #-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
 # Join flood module: Adds support for join flood protection +j X:Y.
 # Closes the channel for N seconds if X users join in Y seconds.

src/modules/m_ircv3_sts.cpp

@@ -0,0 +1,181 @@
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2015 Attila Molnar <attilamolnar@hush.com>
+ *   Copyright (C) 2017 Peter Powell <petpow@saberuk.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 "modules/cap.h"
+#include "modules/ssl.h"
+
+class STSCap : public Cap::Capability
+{
+ private:
+	std::string host;
+	std::string plaintextpolicy;
+	std::string securepolicy;
+
+	bool OnList(LocalUser* user) CXX11_OVERRIDE
+	{
+		// Don't send the cap to clients that only support cap-3.1.
+		if (GetProtocol(user) == Cap::CAP_LEGACY)
+			return false;
+
+		// Plaintext listeners have their own policy.
+		SSLIOHook* sslhook = SSLIOHook::IsSSL(&user->eh);
+		if (!sslhook)
+			return true;
+
+		// If no hostname has been provided for the connection, an STS persistence policy SHOULD NOT be advertised.
+		std::string snihost;
+		if (!sslhook->GetServerName(snihost))
+			return false;
+
+		// Before advertising an STS persistence policy over a secure connection, servers SHOULD verify whether the
+		// hostname provided by clients, for example, via TLS Server Name Indication (SNI), has been whitelisted by
+		// administrators in the server configuration.
+		return InspIRCd::Match(snihost, host, ascii_case_insensitive_map);
+	}
+
+	bool OnRequest(LocalUser* user, bool adding) CXX11_OVERRIDE
+	{
+		// Clients MUST NOT request this capability with CAP REQ. Servers MAY reply with a CAP NAK message if a
+		// client requests this capability.
+		return false;
+	}
+
+	const std::string* GetValue(LocalUser* user) const CXX11_OVERRIDE
+	{
+		return SSLIOHook::IsSSL(&user->eh) ? &securepolicy : &plaintextpolicy;
+	}
+
+ public:
+	STSCap(Module* mod)
+		: Cap::Capability(mod, "sts")
+	{
+	}
+
+	~STSCap()
+	{
+		// TODO: Send duration=0 when STS vanishes.
+	}
+
+	void SetPolicy(const std::string& newhost, unsigned long duration, unsigned int port, bool preload)
+	{
+		// To enforce an STS upgrade policy, servers MUST send this key to insecurely connected clients. Servers
+		// MAY send this key to securely connected clients, but it will be ignored.
+		std::string newplaintextpolicy("port=");
+		newplaintextpolicy.append(ConvToStr(port));
+
+		// To enforce an STS persistence policy, servers MUST send this key to securely connected clients. Servers
+		// MAY send this key to all clients, but insecurely connected clients MUST ignore it.
+		std::string newsecurepolicy("duration=");
+		newsecurepolicy.append(ConvToStr(duration));
+
+		// Servers MAY send this key to all clients, but insecurely connected clients MUST ignore it.
+		if (preload)
+			newsecurepolicy.append(",preload");
+
+		// Apply the new policy.
+		bool changed = false;
+		if (!irc::equals(host, newhost))
+		{
+			ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Changing STS SNI hostname from \"%s\" to \"%s\"", host.c_str(), newhost.c_str());
+			host = newhost;
+			changed = true;
+		}
+
+		if (plaintextpolicy != newplaintextpolicy)
+		{
+			ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Changing plaintext STS policy from \"%s\" to \"%s\"", plaintextpolicy.c_str(), newplaintextpolicy.c_str());
+			plaintextpolicy.swap(newplaintextpolicy);
+			changed = true;
+		}
+
+		if (securepolicy != newsecurepolicy)
+		{
+			ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Changing secure STS policy from \"%s\" to \"%s\"", securepolicy.c_str(), newsecurepolicy.c_str());
+			securepolicy.swap(newsecurepolicy);
+			changed = true;
+		}
+
+		// If the policy has changed then notify all clients via cap-notify.
+		if (changed)
+			NotifyValueChange();
+	}
+};
+
+class ModuleIRCv3STS : public Module
+{
+ private:
+	STSCap cap;
+
+	// The IRCv3 STS specification requires that the server is listening using SSL using a valid certificate.
+	bool HasValidSSLPort(unsigned int port)
+	{
+		for (std::vector<ListenSocket*>::const_iterator iter = ServerInstance->ports.begin(); iter != ServerInstance->ports.end(); ++iter)
+		{
+			ListenSocket* ls = *iter;
+			
+			// Is this listener on the right port?
+			unsigned int saport = ls->bind_sa.port();
+			if (saport != port)
+				continue;
+
+			// Is this listener using SSL?
+			if (ls->bind_tag->getString("ssl").empty())
+				continue;
+
+			// TODO: Add a way to check if a listener's TLS cert is CA-verified.
+			return true;
+		}
+		return false;
+	}
+
+ public:
+	ModuleIRCv3STS()
+		: cap(this)
+	{
+	}
+
+	void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
+	{
+		// TODO: Multiple SNI profiles
+		ConfigTag* tag = ServerInstance->Config->ConfValue("sts");
+		if (tag == ServerInstance->Config->EmptyTag)
+			throw ModuleException("You must define a STS policy!");
+
+		const std::string host = tag->getString("host");
+		if (host.empty())
+			throw ModuleException("<sts:host> must contain a hostname, at " + tag->getTagLocation());
+
+		int port = tag->getInt("port");
+		if (!HasValidSSLPort(port))
+			throw ModuleException("<sts:port> must be a TLS port, at " + tag->getTagLocation());
+
+		unsigned long duration = tag->getDuration("duration", 60*60*24*30*2, 0, LONG_MAX);
+		bool preload = tag->getBool("preload");
+		cap.SetPolicy(host, duration, port, preload);
+	}
+
+	Version GetVersion() CXX11_OVERRIDE
+	{
+		return Version("Provides IRCv3 Strict Transport Security policy advertisement", VF_OPTCOMMON);
+	}
+};
+
+MODULE_INIT(ModuleIRCv3STS)