/* +------------------------------------+ * | Inspire Internet Relay Chat Daemon | * +------------------------------------+ * * InspIRCd: (C) 2002-2009 InspIRCd Development Team * See: http://wiki.inspircd.org/Credits * * This program is free but copyrighted software; see * the file COPYING for details. * * --------------------------------------------------- */ #include "inspircd.h" /* $ModDesc: Provides support for RFC1413 ident lookups */ /* -------------------------------------------------------------- * 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 { private: User *user; /* User we are attached to */ bool done; /* True if lookup is finished */ std::string result; /* Holds the ident string if done */ public: time_t age; IdentRequestSocket(User* u) : user(u), result(u->ident) { age = ServerInstance->Time(); socklen_t size = 0; 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 (ServerInstance->SE->Bind(GetFd(), &bindaddr.sa, size) < 0) { this->Close(); throw ModuleException("failed to bind()"); } ServerInstance->SE->NonBlocking(GetFd()); /* Attempt connection (nonblocking) */ if (ServerInstance->SE->Connect(this, &connaddr.sa, size) == -1 && errno != EINPROGRESS) { this->Close(); throw ModuleException("connect() failed"); } /* Add fd to socket engine */ if (!ServerInstance->SE->AddFd(this, FD_WANT_NO_READ | FD_WANT_POLL_WRITE)) { this->Close(); throw ModuleException("out of fds"); } } virtual void OnConnected() { ServerInstance->Logs->Log("m_ident",DEBUG,"OnConnected()"); ServerInstance->SE->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 (ServerInstance->SE->Send(this, req, req_size, 0) < req_size) done = true; } virtual void HandleEvent(EventType et, int errornum = 0) { switch (et) { case EVENT_READ: /* fd readable event, received ident response */ ReadResponse(); break; case EVENT_WRITE: /* fd writeable event, successfully connected! */ OnConnected(); break; case EVENT_ERROR: /* fd error event, ohshi- */ ServerInstance->Logs->Log("m_ident",DEBUG,"EVENT_ERROR"); /* We *must* Close() here immediately or we get a * huge storm of EVENT_ERROR events! */ Close(); done = true; break; } } 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("m_ident",DEBUG,"Close ident socket %d", GetFd()); ServerInstance->SE->DelFd(this); ServerInstance->SE->Close(GetFd()); ServerInstance->SE->Shutdown(GetFd(), SHUT_WR); this->SetFd(-1); } } bool HasResult() { return done; } /* Note: if the lookup succeeded, will contain 'ident', otherwise * will contain '~ident'. Use *GetResult() to determine lookup success. */ const char* GetResult() { return result.c_str(); } void ReadResponse() { /* 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[MAXBUF]; int recvresult = ServerInstance->SE->Recv(this, ibuf, MAXBUF-1, 0); /* Cant possibly be a valid response shorter than 3 chars, * because the shortest possible response would look like: '1,1' */ if (recvresult < 3) { Close(); done = true; return; } ServerInstance->Logs->Log("m_ident",DEBUG,"ReadResponse()"); irc::sepstream sep(ibuf, ':'); std::string token; for (int i = 0; sep.GetToken(token); i++) { /* We only really care about the 4th portion */ if (i < 3) continue; std::string ident; /* Truncate the ident at any characters we don't like, skip leading spaces */ size_t k = 0; for (const char *j = token.c_str(); *j && (k < ServerInstance->Config->Limits.IdentMax + 1); j++) { if (*j == ' ') continue; /* Rules taken from InspIRCd::IsIdent */ if (((*j >= 'A') && (*j <= '}')) || ((*j >= '0') && (*j <= '9')) || (*j == '-') || (*j == '.')) { ident += *j; continue; } break; } /* Re-check with IsIdent, in case that changes and this doesn't (paranoia!) */ if (!ident.empty() && ServerInstance->IsIdent(ident.c_str())) { result = ident; } break; } /* Close (but dont delete from memory) our socket * and flag as done */ Close(); done = true; return; } }; class ModuleIdent : public Module { int RequestTimeout; ConfigReader *Conf; SimpleExtItem ext; public: ModuleIdent() : ext("ident_socket", this) { Conf = new ConfigReader; OnRehash(NULL); Implementation eventlist[] = { I_OnRehash, I_OnUserRegister, I_OnCheckReady, I_OnUserDisconnect }; ServerInstance->Modules->Attach(eventlist, this, 4); } ~ModuleIdent() { delete Conf; } virtual Version GetVersion() { return Version("Provides support for RFC1413 ident lookups", VF_VENDOR, API_VERSION); } virtual void OnRehash(User *user) { delete Conf; Conf = new ConfigReader; RequestTimeout = Conf->ReadInteger("ident", "timeout", 0, true); if (!RequestTimeout) RequestTimeout = 5; } virtual ModResult OnUserRegister(User *user) { for (int j = 0; j < Conf->Enumerate("connect"); j++) { std::string hostn = Conf->ReadValue("connect","allow",j); /* XXX: Fixme: does not respect port, limit, etc */ if ((InspIRCd::MatchCIDR(user->GetIPString(),hostn, ascii_case_insensitive_map)) || (InspIRCd::Match(user->host,hostn, ascii_case_insensitive_map))) { bool useident = Conf->ReadFlag("connect", "useident", "yes", j); if (!useident) return MOD_RES_PASSTHRU; } } /* User::ident is currently the username field from USER; with m_ident loaded, that * should be preceded by a ~. The field is actually IdentMax+2 characters wide. */ if (user->ident.length() > ServerInstance->Config->Limits.IdentMax + 1) user->ident.assign(user->ident, 0, ServerInstance->Config->Limits.IdentMax); user->ident.insert(0, "~"); user->WriteServ("NOTICE Auth :*** Looking up your ident..."); try { IdentRequestSocket *isock = new IdentRequestSocket(user); ext.set(user, isock); } catch (ModuleException &e) { ServerInstance->Logs->Log("m_ident",DEBUG,"Ident exception: %s", e.GetReason()); } return MOD_RES_PASSTHRU; } /* 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! */ virtual ModResult OnCheckReady(User *user) { /* Does user have an ident socket attached at all? */ IdentRequestSocket *isock = ext.get(user); if (!isock) { ServerInstance->Logs->Log("m_ident",DEBUG, "No ident socket :("); return MOD_RES_PASSTHRU; } ServerInstance->Logs->Log("m_ident",DEBUG, "Has ident_socket"); time_t compare = isock->age; compare += RequestTimeout; /* Check for timeout of the socket */ if (ServerInstance->Time() >= compare) { /* Ident timeout */ user->WriteServ("NOTICE Auth :*** Ident request timed out."); ServerInstance->Logs->Log("m_ident",DEBUG, "Timeout"); /* The user isnt actually disconnecting, * we call this to clean up the user */ OnUserDisconnect(user); return MOD_RES_PASSTHRU; } /* Got a result yet? */ if (!isock->HasResult()) { ServerInstance->Logs->Log("m_ident",DEBUG, "No result yet"); return MOD_RES_DENY; } ServerInstance->Logs->Log("m_ident",DEBUG, "Yay, result!"); /* wooo, got a result (it will be good, or bad) */ if (*(isock->GetResult()) != '~') user->WriteServ("NOTICE Auth :*** Found your ident, '%s'", isock->GetResult()); else user->WriteServ("NOTICE Auth :*** Could not find your ident, using %s instead.", isock->GetResult()); /* Copy the ident string to the user */ user->ChangeIdent(isock->GetResult()); /* The user isnt actually disconnecting, we call this to clean up the user */ OnUserDisconnect(user); return MOD_RES_PASSTHRU; } virtual void OnCleanup(int target_type, void *item) { /* Module unloading, tidy up users */ if (target_type == TYPE_USER) OnUserDisconnect((User*)item); } virtual void OnUserDisconnect(User *user) { /* User disconnect (generic socket detatch event) */ IdentRequestSocket *isock = ext.get(user); if (isock) { isock->Close(); ext.unset(user); } } }; MODULE_INIT(ModuleIdent)