Shuffle the modules about a bit.

1 files changed, 683 insertions, 0 deletions

diff --git a/modules/dnsbl.cpp b/modules/dnsbl.cpp
new file mode 100644
index 000000000..5e63d2280
--- /dev/null
+++ b/modules/dnsbl.cpp
@@ -0,0 +1,683 @@
+/*
+ * InspIRCd -- Internet Relay Chat Daemon
+ *
+ *   Copyright (C) 2021 Dominic Hamon
+ *   Copyright (C) 2020 Matt Schatz <genius3000@g3k.solutions>
+ *   Copyright (C) 2018-2019 linuxdaemon <linuxdaemon.irc@gmail.com>
+ *   Copyright (C) 2017-2024 Sadie Powell <sadie@witchery.services>
+ *   Copyright (C) 2013, 2016 Adam <Adam@anope.org>
+ *   Copyright (C) 2013, 2015-2016 Attila Molnar <attilamolnar@hush.com>
+ *   Copyright (C) 2012 Robby <robby@chatbelgie.be>
+ *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
+ *   Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
+ *   Copyright (C) 2007 Craig Edwards <brain@inspircd.org>
+ *   Copyright (C) 2006-2007, 2009 Robin Burchell <robin+git@viroteck.net>
+ *
+ * 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/>.
+ */
+
+
+#ifndef _WIN32
+# include <arpa/inet.h>
+#endif
+
+#include "inspircd.h"
+#include "extension.h"
+#include "modules/dns.h"
+#include "modules/shun.h"
+#include "modules/stats.h"
+#include "numerichelper.h"
+#include "timeutils.h"
+#include "xline.h"
+
+class DNSBLEntry final
+{
+public:
+	enum class Action
+		: uint8_t
+	{
+		// G-line users who's IP address is in the DNSBL.
+		GLINE,
+
+		// Kill users who's IP address is in the DNSBL.
+		KILL,
+
+		// K-line users who's IP address is in the DNSBL.
+		KLINE,
+
+		// Mark users who's IP address is in the DNSBL.
+		MARK,
+
+		// Shun users who's IP address is in the DNSBL.
+		SHUN,
+
+		// Z-line users who's IP address is in the DNSBL.
+		ZLINE,
+	};
+
+	enum class Type
+		: uint8_t
+	{
+		// DNSBL results will be compared against the specified bit mask.
+		BITMASK,
+
+		// DNSBL results will be compared against a numeric range of values.
+		RECORD,
+	};
+
+	// The action to take against users who's IP address is in this DNSBL.
+	Action action;
+
+	// A bitmask of DNSBL result types to match against.
+	unsigned int bitmask;
+
+	// The domain name of this DNSBL.
+	std::string domain;
+
+	// If action is set to mark then a new hostname to set on users who's IP address is in this DNSBL.
+	std::string markhost;
+
+	// If action is set to mark then a new username to set on users who's IP address is in this DNSBL.
+	std::string markuser;
+
+	// The human readable name of this DNSBL.
+	std::string name;
+
+	// A range of DNSBL result types to match against.
+	CharState records;
+
+	// The message to send to users who's IP address is in a DNSBL.
+	std::string reason;
+
+	// The number of seconds to wait for a DNSBL request before assuming it has failed.
+	unsigned int timeout;
+
+	// The type of result that this DNSBL will provide.
+	Type type;
+
+	// The number of errors which have occurred when querying this DNSBL.
+	unsigned long stats_errors = 0;
+
+	// The number of hits which have occurred when querying this DNSBL.
+	unsigned long stats_hits = 0;
+
+	// The number of misses which have occurred when querying this DNSBL.
+	unsigned long stats_misses = 0;
+
+	// If action is set to gline, kline, or zline then the duration for an X-line to last for.
+	unsigned long xlineduration;
+
+	DNSBLEntry(const Module* mod, const std::shared_ptr<ConfigTag>& tag)
+	{
+		name = tag->getString("name");
+		if (name.empty())
+			throw ModuleException(mod, "<dnsbl:name> can not be empty at " + tag->source.str());
+
+		domain = tag->getString("domain");
+		if (domain.empty())
+			throw ModuleException(mod, "<dnsbl:domain> can not be empty at " + tag->source.str());
+
+		action = tag->getEnum("action", Action::KILL, {
+			{ "gline", Action::GLINE },
+			{ "kill",  Action::KILL  },
+			{ "kline", Action::KLINE },
+			{ "mark",  Action::MARK  },
+			{ "shun",  Action::SHUN  },
+			{ "zline", Action::ZLINE },
+		});
+
+		const std::string typestr = tag->getString("type");
+		if (insp::equalsci(typestr, "bitmask"))
+		{
+			type = Type::BITMASK;
+
+			bitmask = tag->getNum<unsigned int>("bitmask", 0);
+			records = 0;
+		}
+		else if (insp::equalsci(typestr, "record"))
+		{
+			type = Type::RECORD;
+
+			irc::portparser recordrange(tag->getString("records"), false);
+			for (long record = 0; (record = recordrange.GetToken()); )
+			{
+				if (record < 0 || record > UCHAR_MAX)
+					throw ModuleException(mod, "<dnsbl:records> can only hold records between 0 and 255 at " + tag->source.str());
+
+				records.set(record);
+			}
+		}
+		else
+		{
+			throw ModuleException(mod, typestr + " is an invalid value for <dnsbl:type>; acceptable values are 'bitmask' or 'records' at "
+				+ tag->source.str());
+		}
+
+		reason = tag->getString("reason", "Your IP (%ip%) has been blacklisted by the %dnsbl% DNSBL.", 1, ServerInstance->Config->Limits.MaxLine);
+		timeout = static_cast<unsigned int>(tag->getDuration("timeout", 0, 1, 60));
+		markuser = tag->getString("user");
+		markhost = tag->getString("host");
+		xlineduration = tag->getDuration("duration", 60*60, 1);
+	}
+};
+
+class DNSBLMask final
+{
+public:
+	// The username to give a user because they were in a DNSBL (<dnsbl:user>).
+	std::string user;
+
+	// The hostname to give a user because they were in a DNSBL (<dnsbl:host>).
+	std::string host;
+
+	// The reason why the user was given this user@host (<dnsbl:reason>).
+	std::string reason;
+
+	DNSBLMask(const std::shared_ptr<DNSBLEntry>& cfg, const std::string& msg)
+		: user(cfg->markuser)
+		, host(cfg->markhost)
+		, reason(msg)
+	{
+	}
+};
+
+typedef std::vector<std::shared_ptr<DNSBLEntry>> DNSBLEntries;
+typedef SimpleExtItem<DNSBLMask> MaskExtItem;
+typedef ListExtItem<std::vector<std::string>> MarkExtItem;
+
+// Data which is shared with DNS lookup classes.
+class SharedData final
+{
+private:
+	std::string ReverseIP(const irc::sockets::sockaddrs& sa)
+	{
+		switch (sa.family())
+		{
+			case AF_INET:
+			{
+				auto a = (unsigned int) sa.in4.sin_addr.s_addr & 0xFF;
+				auto b = (unsigned int) (sa.in4.sin_addr.s_addr >> 8) & 0xFF;
+				auto c = (unsigned int) (sa.in4.sin_addr.s_addr >> 16) & 0xFF;
+				auto d = (unsigned int) (sa.in4.sin_addr.s_addr >> 24) & 0xFF;
+				return fmt::format("{}.{}.{}.{}", d, c, b, a);
+			}
+
+			case AF_INET6:
+			{
+				const std::string hexaddr = Hex::Encode(sa.in6.sin6_addr.s6_addr, 16);
+				std::string reversedip;
+				reversedip.reserve(hexaddr.length() * 2);
+				for (const auto hexchr : insp::reverse_range(hexaddr))
+				{
+					reversedip.push_back(hexchr);
+					reversedip.push_back('.');
+				}
+				reversedip.pop_back();
+				return reversedip;
+			}
+
+			default:
+				break;
+		}
+
+		// Clients can't be in a DNSBL if they aren't connected via IPv4 or IPv6.
+		return {};
+	}
+
+public:
+	// Counts the number of DNSBL lookups waiting for this user.
+	IntExtItem countext;
+
+	// Reference to the DNS manager.
+	DNS::ManagerRef dns;
+
+	// The DNSBL entries from the config.
+	DNSBLEntries dnsbls;
+
+	// The DNSBL marks which are set on a user.
+	MarkExtItem markext;
+
+	// The user@host to set on a marked user when they are connected.
+	MaskExtItem maskext;
+
+	SharedData(Module* mod)
+		: countext(mod, "dnsbl-pending", ExtensionType::USER)
+		, dns(mod)
+		, markext(mod, "dnsbl-match", ExtensionType::USER)
+		, maskext(mod, "dnsbl-mask", ExtensionType::USER)
+	{
+	}
+
+	// Performs one or more DNSBL lookups on the specified user.
+	void Lookup(LocalUser* user);
+};
+
+class DNSBLResolver final
+	: public DNS::Request
+{
+private:
+	std::shared_ptr<DNSBLEntry> config;
+	SharedData& data;
+	const irc::sockets::sockaddrs sa;
+	const std::string uuid;
+
+	template <typename Line, typename... Extra>
+	void AddLine(const char* type, const std::string& reason, unsigned long duration, LocalUser* user, Extra&&... extra)
+	{
+		if (user->exempt)
+			return; // This user shouldn't be banned.
+
+		auto line = new Line(ServerInstance->Time(), duration, MODNAME "@" + ServerInstance->Config->ServerName, reason, std::forward<Extra>(extra)...);
+		if (!ServerInstance->XLines->AddLine(line, nullptr))
+		{
+			ServerInstance->Users.QuitUser(user, "Killed (" + reason + ")");
+			delete line;
+			return;
+		}
+
+		ServerInstance->SNO.WriteToSnoMask('x', "{} added a timed {} on {}, expires in {} (on {}): {}",
+			line->source, type, line->Displayable(), Duration::ToString(line->duration),
+			Time::ToString(line->expiry), line->reason);
+		ServerInstance->XLines->ApplyLines();
+	}
+
+public:
+	DNSBLResolver(Module* mod, SharedData& sd, const std::string& hostname, LocalUser* u, const std::shared_ptr<DNSBLEntry>& cfg)
+		: DNS::Request(*sd.dns, mod, hostname, DNS::QUERY_A, true, cfg->timeout)
+		, config(cfg)
+		, data(sd)
+		, sa(u->client_sa)
+		, uuid(u->uuid)
+	{
+	}
+
+	/* Note: This may be called multiple times for multiple A record results */
+	void OnLookupComplete(const DNS::Query* r) override
+	{
+		/* Check the user still exists */
+		LocalUser* them = ServerInstance->Users.FindUUID<LocalUser>(uuid);
+		if (!them || them->client_sa != sa)
+		{
+			config->stats_misses++;
+			return;
+		}
+
+		intptr_t i = data.countext.Get(them);
+		if (i)
+			data.countext.Set(them, i - 1);
+
+		// The DNSBL reply must contain an A result.
+		const DNS::ResourceRecord* const ans_record = r->FindAnswerOfType(DNS::QUERY_A);
+		if (!ans_record)
+		{
+			config->stats_errors++;
+			ServerInstance->SNO.WriteGlobalSno('d', "{} returned an result with no IPv4 address.",
+				config->name);
+			return;
+		}
+
+		// The DNSBL reply must be a valid IPv4 address.
+		in_addr resultip;
+		if (inet_pton(AF_INET, ans_record->rdata.c_str(), &resultip) != 1)
+		{
+			config->stats_errors++;
+			ServerInstance->SNO.WriteGlobalSno('d', "{} returned an invalid IPv4 address: {}",
+				config->name, ans_record->rdata);
+			return;
+		}
+
+		// The DNSBL reply should be in the 127.0.0.0/8 range.
+		if ((resultip.s_addr & 0xFF) != 127)
+		{
+			config->stats_errors++;
+			ServerInstance->SNO.WriteGlobalSno('d', "{} returned an IPv4 address which is outside of the 127.0.0.0/8 subnet: {}",
+				config->name, ans_record->rdata);
+			return;
+		}
+
+		bool match = false;
+		unsigned int result = 0;
+		switch (config->type)
+		{
+			case DNSBLEntry::Type::BITMASK:
+			{
+				result = (resultip.s_addr >> 24) & config->bitmask;
+				match = (result != 0);
+				break;
+			}
+			case DNSBLEntry::Type::RECORD:
+			{
+				result = resultip.s_addr >> 24;
+				match = (config->records[result] == 1);
+				break;
+			}
+		}
+
+		if (match)
+		{
+			const std::string reason = Template::Replace(config->reason, {
+				{ "dnsbl",       config->name                                     },
+				{ "dnsbl.url",   Percent::Encode(config->name)                    },
+				{ "ip",          them->GetAddress()                               },
+				{ "network",     ServerInstance->Config->Network                  },
+				{ "network.url", Percent::Encode(ServerInstance->Config->Network) },
+				{ "result",      ConvToStr(result)                                },
+			});
+
+			config->stats_hits++;
+
+			switch (config->action)
+			{
+				case DNSBLEntry::Action::KILL:
+				{
+					if (!them->exempt)
+						ServerInstance->Users.QuitUser(them, "Killed (" + reason + ")");
+					break;
+				}
+				case DNSBLEntry::Action::MARK:
+				{
+					if (!config->markuser.empty() || !config->markhost.empty())
+					{
+						// Store the u@h mask for later to avoid being overwritten by username/hostname lookups.
+						data.maskext.SetFwd(them, config, reason);
+
+						// If the user is already connected we should just do this now.
+						if (them->IsFullyConnected())
+							creator->OnUserConnect(them);
+					}
+
+					data.markext.GetRef(them).push_back(config->name);
+					break;
+				}
+				case DNSBLEntry::Action::KLINE:
+				{
+					AddLine<KLine>("K-line", reason, config->xlineduration, them, them->GetBanUser(true), them->GetAddress());
+					break;
+				}
+				case DNSBLEntry::Action::GLINE:
+				{
+					AddLine<GLine>("G-line", reason, config->xlineduration, them, them->GetBanUser(true), them->GetAddress());
+					break;
+				}
+				case DNSBLEntry::Action::ZLINE:
+				{
+					AddLine<ZLine>("Z-line", reason, config->xlineduration, them, them->GetAddress());
+					break;
+				}
+				case DNSBLEntry::Action::SHUN:
+				{
+					AddLine<Shun>("Shun", reason, config->xlineduration, them, them->GetAddress());
+					break;
+				}
+			}
+
+			ServerInstance->SNO.WriteGlobalSno('d', "{} {} ({}) detected as being on the '{}' DNSBL with result {}{}",
+				them->IsFullyConnected() ? "User" : "Connecting user", them->GetRealMask(), them->GetAddress(),
+				config->name, result, them->exempt ? " -- exempt" : "");
+		}
+		else
+			config->stats_misses++;
+	}
+
+	void OnError(const DNS::Query* q) override
+	{
+		bool is_miss = true;
+		switch (q->error)
+		{
+			case DNS::ERROR_NO_RECORDS:
+			case DNS::ERROR_DOMAIN_NOT_FOUND:
+				config->stats_misses++;
+				break;
+
+			default:
+				config->stats_errors++;
+				is_miss = false;
+				break;
+		}
+
+		LocalUser* them = ServerInstance->Users.FindUUID<LocalUser>(uuid);
+		if (!them || them->client_sa != sa)
+			return;
+
+		intptr_t i = data.countext.Get(them);
+		if (i)
+			data.countext.Set(them, i - 1);
+
+		if (is_miss)
+			return;
+
+		ServerInstance->SNO.WriteGlobalSno('d', "An error occurred whilst checking whether {} ({}) is on the '{}' DNSBL: {}",
+			them->GetRealMask(), them->GetAddress(), config->name, data.dns->GetErrorStr(q->error));
+	}
+};
+
+class CommandDNSBL final
+	: public Command
+{
+private:
+	SharedData& data;
+
+public:
+	CommandDNSBL(Module* mod, SharedData& sd)
+		: Command(mod, "DNSBL", 1, 2)
+		, data(sd)
+	{
+		access_needed = CmdAccess::OPERATOR;
+		syntax = { "[<nick> [<reason>]]" };
+		translation = { TR_NICK, TR_TEXT };
+	}
+
+	CmdResult Handle(User* user, const Params& parameters) override
+	{
+		User* target;
+		if (IS_LOCAL(user))
+			target = ServerInstance->Users.FindNick(parameters[0], true);
+		else
+			target = ServerInstance->Users.FindUUID(parameters[0], true);
+
+		// We couldn't find the user so just give up.
+		if (!target)
+		{
+			user->WriteNumeric(Numerics::NoSuchNick(parameters[0]));
+			return CmdResult::FAILURE;
+		}
+
+		auto* ltarget = IS_LOCAL(target);
+		if (!ltarget)
+			return CmdResult::SUCCESS; // The user is on another server so just let it forward.
+
+		intptr_t count = data.countext.Get(ltarget);
+		if (count)
+		{
+			// TODO: replace this with a FAIL stdrpl when we can network those.
+			user->WriteRemoteNotice(fmt::format("*** DNSBL: Unable to recheck {}: still waiting on {} DNSBLs from the previous check.",
+				ltarget->nick, count));
+			return CmdResult::FAILURE;
+		}
+
+		// TODO: replace this with a NOTE stdrpl when we can network those.
+		user->WriteRemoteNotice(fmt::format("*** DNSBL: Rechecking {} against {} DNSBLs.", ltarget->nick, data.dnsbls.size()));
+
+		const bool has_reason = parameters.size() > 1;
+		ServerInstance->SNO.WriteGlobalSno('d', "{} is rechecking whether {} ({}) is in a DNSBL{}{}", user->nick,
+			ltarget->nick, ltarget->GetAddress(),  has_reason ? ": " : "", has_reason ? parameters[1] : ".");
+
+		data.Lookup(ltarget);
+		return CmdResult::SUCCESS;
+	}
+
+	RouteDescriptor GetRouting(User* user, const Params& parameters) override
+	{
+		return ROUTE_OPT_UCAST(parameters[0]);
+	}
+};
+
+void SharedData::Lookup(LocalUser* user)
+{
+	if (!dns)
+		return; // The core_dns module is not loaded.
+
+	if (!user->GetClass()->config->getBool("usednsbl", true))
+		return; // The user's class is exempt from DNSBL lookups.
+
+	const std::string reversedip = ReverseIP(user->client_sa);
+	ServerInstance->Logs.Debug(MODNAME, "Reversed IP {} => {}", user->GetAddress(), reversedip);
+
+	countext.Set(user, dnsbls.size());
+
+	// For each DNSBL, we will run through this lookup
+	for (const auto& dnsbl : dnsbls)
+	{
+		// Fill hostname with a dnsbl style host (d.c.b.a.domain.tld)
+		const std::string hostname = reversedip + "." + dnsbl->domain;
+
+		// Try to do the DNSBL lookup.
+		auto* r = new DNSBLResolver(dns->creator, *this, hostname, user, dnsbl);
+		try
+		{
+			dns->Process(r);
+		}
+		catch (const DNS::Exception& ex)
+		{
+			delete r;
+			ServerInstance->Logs.Debug(MODNAME, "DNSBL lookup error: {}", ex.GetReason());
+		}
+
+		if (user->quitting)
+			break; // DNS resolver found a cached hit.
+	}
+}
+
+class ModuleDNSBL final
+	: public Module
+	, public Stats::EventListener
+{
+private:
+	SharedData data;
+	CommandDNSBL cmd;
+
+public:
+	ModuleDNSBL()
+		: Module(VF_VENDOR, "Allows the server administrator to check the IP address of connecting users against a DNSBL.")
+		, Stats::EventListener(this)
+		, data(this)
+		, cmd(this, data)
+	{
+	}
+
+	void init() override
+	{
+		ServerInstance->SNO.EnableSnomask('d', "DNSBL");
+	}
+
+	void Prioritize() override
+	{
+		Module* corexline = ServerInstance->Modules.Find("core_xline");
+		ServerInstance->Modules.SetPriority(this, I_OnChangeRemoteAddress, PRIORITY_AFTER, corexline);
+	}
+
+	void ReadConfig(ConfigStatus& status) override
+	{
+		DNSBLEntries newdnsbls;
+		for (const auto& [_, tag] : ServerInstance->Config->ConfTags("dnsbl"))
+		{
+			auto entry = std::make_shared<DNSBLEntry>(this, tag);
+			newdnsbls.push_back(entry);
+		}
+		data.dnsbls.swap(newdnsbls);
+	}
+
+	void OnChangeRemoteAddress(LocalUser* user) override
+	{
+		if (!user->quitting && user->GetClass())
+			data.Lookup(user);
+	}
+
+	ModResult OnPreChangeConnectClass(LocalUser* user, const std::shared_ptr<ConnectClass>& klass, std::optional<Numeric::Numeric>& errnum) override
+	{
+		const std::string dnsbl = klass->config->getString("dnsbl");
+		if (dnsbl.empty())
+			return MOD_RES_PASSTHRU;
+
+		MarkExtItem::List* match = data.markext.Get(user);
+		if (!match)
+		{
+			ServerInstance->Logs.Debug("CONNECTCLASS", "The {} connect class is not suitable as it requires a DNSBL mark.",
+				klass->GetName());
+			return MOD_RES_DENY;
+		}
+
+		for (const auto& mark : *match)
+		{
+			if (InspIRCd::Match(mark, dnsbl))
+				return MOD_RES_PASSTHRU;
+		}
+
+		ServerInstance->Logs.Debug("CONNECTCLASS", "The {} connect class is not suitable as the DNSBL marks ({}) do not match {}.",
+			klass->GetName(), insp::join(*match, ", "), dnsbl);
+		return MOD_RES_DENY;
+	}
+
+	ModResult OnCheckReady(LocalUser* user) override
+	{
+		// Block until all of the DNSBL lookups are complete.
+		return data.countext.Get(user) ? MOD_RES_DENY : MOD_RES_PASSTHRU;
+	}
+
+	void OnUserConnect(LocalUser* user) override
+	{
+		DNSBLMask* ih = data.maskext.Get(user);
+		if (ih)
+		{
+			if (!ih->user.empty())
+			{
+				user->ChangeDisplayedUser(ih->user);
+				user->WriteNotice("Your username has been set to " + ih->user + ": " + ih->reason);
+			}
+
+			if (!ih->host.empty())
+			{
+				user->ChangeDisplayedHost(ih->host);
+				user->WriteNotice("Your hostname has been set to " + ih->host + ": " + ih->reason);
+			}
+
+			data.maskext.Unset(user);
+		}
+	}
+
+	ModResult OnStats(Stats::Context& stats) override
+	{
+		if (stats.GetSymbol() != 'd')
+			return MOD_RES_PASSTHRU;
+
+		unsigned long total_hits = 0;
+		unsigned long total_misses = 0;
+		unsigned long total_errors = 0;
+		for (const auto& dnsbl : data.dnsbls)
+		{
+			total_hits += dnsbl->stats_hits;
+			total_misses += dnsbl->stats_misses;
+			total_errors += dnsbl->stats_errors;
+
+			stats.AddGenericRow(fmt::format("The \"{}\" DNSBL had {} hits, {} misses, and {} errors",
+				dnsbl->name, dnsbl->stats_hits, dnsbl->stats_misses, dnsbl->stats_errors));
+		}
+
+		stats.AddGenericRow("Total DNSBL hits: " + ConvToStr(total_hits));
+		stats.AddGenericRow("Total DNSBL misses: " + ConvToStr(total_misses));
+		stats.AddGenericRow("Total DNSBL errors: " + ConvToStr(total_errors));
+		return MOD_RES_DENY;
+	}
+};
+
+MODULE_INIT(ModuleDNSBL)