summaryrefslogtreecommitdiff
path: root/src/modules/m_ircv3_sts.cpp
blob: 86ea159c185a92c0f206cdf961245e2db3a6aa51 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2017-2019 Sadie Powell <sadie@witchery.services>
 *
 * 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;

		// Don't send the cap to clients in a class which has STS disabled.
		if (!user->GetClass()->config->getBool("usests", true))
			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")
	{
		DisableAutoRegister();
	}

	~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());

		unsigned int port = tag->getUInt("port", 0, 0, UINT16_MAX);
		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);
		bool preload = tag->getBool("preload");
		cap.SetPolicy(host, duration, port, preload);

		if (!cap.IsRegistered())
			ServerInstance->Modules->AddService(cap);
	}

	Version GetVersion() CXX11_OVERRIDE
	{
		return Version("Provides IRCv3 Strict Transport Security policy advertisement", VF_OPTCOMMON|VF_VENDOR);
	}
};

MODULE_INIT(ModuleIRCv3STS)