/* * InspIRCd -- Internet Relay Chat Daemon * * Copyright (C) 2009-2010 Daniel De Graaf * Copyright (C) 2007, 2009 John Brooks * Copyright (C) 2006-2008 Robin Burchell * Copyright (C) 2005-2008 Craig Edwards * Copyright (C) 2008 Thomas Stagner * Copyright (C) 2007 Dennis Friis * * 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 . */ #include "inspircd.h" /* -------------------------------------------------------------- * Note that this is the third incarnation of m_ident. The first * two attempts were pretty crashy, mainly due to the fact we tried * to use InspSocket/BufferedSocket to make them work. This class * is ok for more heavyweight tasks, it does a lot of things behind * the scenes that are not good for ident sockets and it has a huge * memory footprint! * * To fix all the issues that we had in the old ident modules (many * nasty race conditions that would cause segfaults etc) we have * rewritten this module to use a simplified socket object based * directly off EventHandler. As EventHandler only has low level * readability, writeability and error events tied directly to the * socket engine, this makes our lives easier as nothing happens to * our ident lookup class that is outside of this module, or out- * side of the control of the class. There are no timers, internal * events, or such, which will cause the socket to be deleted, * queued for deletion, etc. In fact, theres not even any queueing! * * Using this framework we have a much more stable module. * * A few things to note: * * O The only place that may *delete* an active or inactive * ident socket is OnUserDisconnect in the module class. * Because this is out of scope of the socket class there is * no possibility that the socket may ever try to delete * itself. * * O Closure of the ident socket with the Close() method will * not cause removal of the socket from memory or detatchment * from its 'parent' User class. It will only flag it as an * inactive socket in the socket engine. * * O Timeouts are handled in OnCheckReaady at the same time as * checking if the ident socket has a result. This is done * by checking if the age the of the class (its instantiation * time) plus the timeout value is greater than the current time. * * O The ident socket is able to but should not modify its * 'parent' user directly. Instead the ident socket class sets * a completion flag and during the next call to OnCheckReady, * the completion flag will be checked and any result copied to * that user's class. This again ensures a single point of socket * deletion for safer, neater code. * * O The code in the constructor of the ident socket is taken from * BufferedSocket but majorly thinned down. It works for both * IPv4 and IPv6. * * O In the event that the ident socket throws a ModuleException, * nothing is done. This is counted as total and complete * failure to create a connection. * -------------------------------------------------------------- */ class IdentRequestSocket : public EventHandler { public: LocalUser *user; /* User we are attached to */ std::string result; /* Holds the ident string if done */ time_t age; bool done; /* True if lookup is finished */ IdentRequestSocket(LocalUser* u) : user(u) { age = ServerInstance->Time(); SetFd(socket(user->server_sa.sa.sa_family, SOCK_STREAM, 0)); if (GetFd() == -1) throw ModuleException("Could not create socket"); done = false; irc::sockets::sockaddrs bindaddr; irc::sockets::sockaddrs connaddr; memcpy(&bindaddr, &user->server_sa, sizeof(bindaddr)); memcpy(&connaddr, &user->client_sa, sizeof(connaddr)); if (connaddr.sa.sa_family == AF_INET6) { bindaddr.in6.sin6_port = 0; connaddr.in6.sin6_port = htons(113); } else { bindaddr.in4.sin_port = 0; connaddr.in4.sin_port = htons(113); } /* Attempt to bind (ident requests must come from the ip the query is referring to */ if (SocketEngine::Bind(GetFd(), bindaddr) < 0) { this->Close(); throw ModuleException("failed to bind()"); } SocketEngine::NonBlocking(GetFd()); /* Attempt connection (nonblocking) */ if (SocketEngine::Connect(this, &connaddr.sa, connaddr.sa_size()) == -1 && errno != EINPROGRESS) { this->Close(); throw ModuleException("connect() failed"); } /* Add fd to socket engine */ if (!SocketEngine::AddFd(this, FD_WANT_NO_READ | FD_WANT_POLL_WRITE)) { this->Close(); throw ModuleException("out of fds"); } } void OnEventHandlerWrite() CXX11_OVERRIDE { SocketEngine::ChangeEventMask(this, FD_WANT_POLL_READ | FD_WANT_NO_WRITE); char req[32]; /* Build request in the form 'localport,remoteport\r\n' */ int req_size; if (user->client_sa.sa.sa_family == AF_INET6) req_size = snprintf(req, sizeof(req), "%d,%d\r\n", ntohs(user->client_sa.in6.sin6_port), ntohs(user->server_sa.in6.sin6_port)); else req_size = snprintf(req, sizeof(req), "%d,%d\r\n", ntohs(user->client_sa.in4.sin_port), ntohs(user->server_sa.in4.sin_port)); /* Send failed if we didnt write the whole ident request -- * might as well give up if this happens! */ if (SocketEngine::Send(this, req, req_size, 0) < req_size) done = true; } void Close() { /* Remove ident socket from engine, and close it, but dont detatch it * from its parent user class, or attempt to delete its memory. */ if (GetFd() > -1) { ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Close ident socket %d", GetFd()); SocketEngine::Close(this); } } bool HasResult() { return done; } void OnEventHandlerRead() CXX11_OVERRIDE { /* We don't really need to buffer for incomplete replies here, since IDENT replies are * extremely short - there is *no* sane reason it'd be in more than one packet */ char ibuf[256]; int recvresult = SocketEngine::Recv(this, ibuf, sizeof(ibuf)-1, 0); /* Close (but don't delete from memory) our socket * and flag as done since the ident lookup has finished */ Close(); done = true; /* Cant possibly be a valid response shorter than 3 chars, * because the shortest possible response would look like: '1,1' */ if (recvresult < 3) return; ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "ReadResponse()"); /* Truncate at the first null character, but first make sure * there is at least one null char (at the end of the buffer). */ ibuf[recvresult] = '\0'; std::string buf(ibuf); /* <2 colons: invalid * 2 colons: reply is an error * >3 colons: there is a colon in the ident */ if (std::count(buf.begin(), buf.end(), ':') != 3) return; std::string::size_type lastcolon = buf.rfind(':'); /* Truncate the ident at any characters we don't like, skip leading spaces */ for (std::string::const_iterator i = buf.begin()+lastcolon+1; i != buf.end(); ++i) { if (result.size() == ServerInstance->Config->Limits.IdentMax) /* Ident is getting too long */ break; if (*i == ' ') continue; /* Add the next char to the result and see if it's still a valid ident, * according to IsIdent(). If it isn't, then erase what we just added and * we're done. */ result += *i; if (!ServerInstance->IsIdent(result)) { result.erase(result.end()-1); break; } } } void OnEventHandlerError(int errornum) CXX11_OVERRIDE { Close(); done = true; } CullResult cull() CXX11_OVERRIDE { Close(); return EventHandler::cull(); } }; class ModuleIdent : public Module { int RequestTimeout; bool NoLookupPrefix; SimpleExtItem ext; public: ModuleIdent() : ext("ident_socket", ExtensionItem::EXT_USER, this) { } Version GetVersion() CXX11_OVERRIDE { return Version("Provides support for RFC1413 ident lookups", VF_VENDOR); } void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE { ConfigTag* tag = ServerInstance->Config->ConfValue("ident"); RequestTimeout = tag->getDuration("timeout", 5, 1); NoLookupPrefix = tag->getBool("nolookupprefix", false); } void OnUserInit(LocalUser *user) CXX11_OVERRIDE { ConfigTag* tag = user->MyClass->config; if (!tag->getBool("useident", true)) return; user->WriteNotice("*** Looking up your ident..."); try { IdentRequestSocket *isock = new IdentRequestSocket(user); ext.set(user, isock); } catch (ModuleException &e) { ServerInstance->Logs->Log(MODNAME, LOG_DEBUG, "Ident exception: " + e.GetReason()); } } /* This triggers pretty regularly, we can use it in preference to * creating a Timer object and especially better than creating a * Timer per ident lookup! */ ModResult OnCheckReady(LocalUser *user) CXX11_OVERRIDE { /* Does user have an ident socket attached at all? */ IdentRequestSocket *isock = ext.get(user); if (!isock) { if ((NoLookupPrefix) && (user->ident[0] != '~')) user->ident.insert(user->ident.begin(), 1, '~'); return MOD_RES_PASSTHRU; } time_t compare = isock->age; compare += RequestTimeout; /* Check for timeout of the socket */ if (ServerInstance->Time() >= compare) { /* Ident timeout */ user->WriteNotice("*** Ident request timed out."); } else if (!isock->HasResult()) { // time still good, no result yet... hold the registration return MOD_RES_DENY; } /* wooo, got a result (it will be good, or bad) */ if (isock->result.empty()) { user->ident.insert(user->ident.begin(), 1, '~'); user->WriteNotice("*** Could not find your ident, using " + user->ident + " instead."); } else { user->ident = isock->result; user->WriteNotice("*** Found your ident, '" + user->ident + "'"); } user->InvalidateCache(); isock->Close(); ext.unset(user); return MOD_RES_PASSTHRU; } ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass) CXX11_OVERRIDE { if (myclass->config->getBool("requireident") && user->ident[0] == '~') return MOD_RES_DENY; return MOD_RES_PASSTHRU; } }; MODULE_INIT(ModuleIdent)