/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
* Copyright (C) 2007, 2009 John Brooks <john.brooks@dereferenced.net>
* Copyright (C) 2006-2008 Robin Burchell <robin+git@viroteck.net>
* Copyright (C) 2005-2008 Craig Edwards <craigedwards@brainbox.cc>
* Copyright (C) 2008 Thomas Stagner <aquanight@inspircd.org>
* Copyright (C) 2007 Dennis Friis <peavey@inspircd.org>
*
* 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"
/* $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
{
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 (ServerInstance->SE->Bind(GetFd(), bindaddr) < 0)
{
this->Close();
throw ModuleException("failed to bind()");
}
ServerInstance->SE->NonBlocking(GetFd());
/* Attempt connection (nonblocking) */
if (ServerInstance->SE->Connect(this, &connaddr.sa, 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());
this->SetFd(-1);
}
}
bool HasResult()
{
return done;
}
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;
SimpleExtItem<IdentRequestSocket> ext;
public:
ModuleIdent() : ext("ident_socket", this)
{
OnRehash(NULL);
Implementation eventlist[] = {
I_OnRehash, I_OnUserInit, I_OnCheckReady,
I_OnUserDisconnect, I_OnSetConnectClass
};
ServerInstance->Modules->Attach(eventlist, this, 5);
}
~ModuleIdent()
{
}
virtual Version GetVersion()
{
return Version("Provides support for RFC1413 ident lookups", VF_VENDOR);
}
virtual void OnRehash(User *user)
{
ConfigReader Conf;
RequestTimeout = Conf.ReadInteger("ident", "timeout", 0, true);
if (!RequestTimeout)
RequestTimeout = 5;
}
void OnUserInit(LocalUser *user)
{
ConfigTag* tag = user->MyClass->config;
if (!tag->getBool("useident", true))
return;
user->WriteServ("NOTICE Auth :*** Looking up your ident...");
try
{
IdentRequestSocket *isock = new IdentRequestSocket(IS_LOCAL(user));
ext.set(user, isock);
}
catch (ModuleException &e)
{
ServerInstance->Logs->Log("m_ident",DEBUG,"Ident exception: %s", 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!
*/
virtual ModResult OnCheckReady(LocalUser *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");
}
else if (!isock->HasResult())
{
// time still good, no result yet... hold the registration
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->result.empty())
{
user->ident.insert(0, 1, '~');
user->WriteServ("NOTICE Auth :*** Could not find your ident, using %s instead.", user->ident.c_str());
}
else
{
user->ident = isock->result;
user->WriteServ("NOTICE Auth :*** Found your ident, '%s'", user->ident.c_str());
}
isock->Close();
ext.unset(user);
return MOD_RES_PASSTHRU;
}
ModResult OnSetConnectClass(LocalUser* user, ConnectClass* myclass)
{
if (myclass->config->getBool("requireident") && user->ident[0] == '~')
return MOD_RES_DENY;
return MOD_RES_PASSTHRU;
}
virtual void OnCleanup(int target_type, void *item)
{
/* Module unloading, tidy up users */
if (target_type == TYPE_USER)
OnUserDisconnect((LocalUser*)item);
}
virtual void OnUserDisconnect(LocalUser *user)
{
/* User disconnect (generic socket detatch event) */
IdentRequestSocket *isock = ext.get(user);
if (isock)
{
isock->Close();
ext.unset(user);
}
}
};
MODULE_INIT(ModuleIdent)
