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Created November 19, 2018 13:14
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Revisited m_filter.cpp
/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2009 Daniel De Graaf <[email protected]>
* Copyright (C) 2004, 2008 Craig Edwards <[email protected]>
* Copyright (C) 2007 Dennis Friis <[email protected]>
* Copyright (C) 2007 Robin Burchell <[email protected]>
*
* 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 "xline.h"
#include "m_regex.h"
/* $ModDesc: Text (spam) filtering */
class ModuleFilter;
enum FilterFlags
{
FLAG_PART = 2,
FLAG_QUIT = 4,
FLAG_PRIVMSG = 8,
FLAG_NOTICE = 16
};
enum FilterAction
{
FA_GLINE,
FA_BLOCK,
FA_SILENT,
FA_KILL,
FA_WARN
};
class FilterResult
{
public:
std::string freeform;
std::string reason;
FilterAction action;
long gline_time;
bool flag_no_opers;
bool flag_part_message;
bool flag_quit_message;
bool flag_privmsg;
bool flag_notice;
bool flag_strip_color;
FilterResult(const std::string& free, const std::string& rea, FilterAction act, long gt, const std::string& fla) :
freeform(free), reason(rea), action(act), gline_time(gt)
{
this->FillFlags(fla);
}
char FillFlags(const std::string &fl)
{
flag_no_opers = flag_part_message = flag_quit_message = flag_privmsg =
flag_notice = flag_strip_color = false;
for (std::string::const_iterator n = fl.begin(); n != fl.end(); ++n)
{
switch (*n)
{
case 'o':
flag_no_opers = true;
break;
case 'P':
flag_part_message = true;
break;
case 'q':
flag_quit_message = true;
break;
case 'p':
flag_privmsg = true;
break;
case 'n':
flag_notice = true;
break;
case 'c':
flag_strip_color = true;
break;
case '*':
flag_no_opers = flag_part_message = flag_quit_message =
flag_privmsg = flag_notice = flag_strip_color = true;
break;
default:
return *n;
break;
}
}
return 0;
}
std::string GetFlags()
{
std::string flags;
if (flag_no_opers)
flags.push_back('o');
if (flag_part_message)
flags.push_back('P');
if (flag_quit_message)
flags.push_back('q');
if (flag_privmsg)
flags.push_back('p');
if (flag_notice)
flags.push_back('n');
/* Order is important here, 'c' must be the last char in the string as it is unsupported
* on < 2.0.10, and the logic in FillFlags() stops parsing when it ecounters an unknown
* character.
*/
if (flag_strip_color)
flags.push_back('c');
if (flags.empty())
flags.push_back('-');
return flags;
}
FilterResult()
{
}
};
class CommandFilter : public Command
{
public:
CommandFilter(Module* f)
: Command(f, "FILTER", 1, 5)
{
flags_needed = 'o';
this->syntax = "<filter-definition> <action> <flags> [<gline-duration>] :<reason>";
}
CmdResult Handle(const std::vector<std::string>&, User*);
RouteDescriptor GetRouting(User* user, const std::vector<std::string>& parameters)
{
return ROUTE_BROADCAST;
}
};
class ImplFilter : public FilterResult
{
public:
Regex* regex;
ImplFilter(ModuleFilter* mymodule, const std::string &rea, FilterAction act, long glinetime, const std::string &pat, const std::string &flgs);
};
class ModuleFilter : public Module
{
bool initing;
RegexFactory* factory;
void FreeFilters();
public:
CommandFilter filtcommand;
dynamic_reference<RegexFactory> RegexEngine;
std::vector<ImplFilter> filters;
int flags;
std::set<std::string> exemptfromfilter; // List of channel names excluded from filtering.
ModuleFilter();
void init();
CullResult cull();
ModResult OnUserPreMessage(User* user,void* dest,int target_type, std::string &text, char status, CUList &exempt_list);
FilterResult* FilterMatch(User* user, const std::string &text, int flags);
bool DeleteFilter(const std::string &freeform);
std::pair<bool, std::string> AddFilter(const std::string &freeform, FilterAction type, const std::string &reason, long duration, const std::string &flags);
ModResult OnUserPreNotice(User* user,void* dest,int target_type, std::string &text, char status, CUList &exempt_list);
void OnRehash(User* user);
Version GetVersion();
std::string EncodeFilter(FilterResult* filter);
FilterResult DecodeFilter(const std::string &data);
void OnSyncNetwork(Module* proto, void* opaque);
void OnDecodeMetaData(Extensible* target, const std::string &extname, const std::string &extdata);
ModResult OnStats(char symbol, User* user, string_list &results);
ModResult OnPreCommand(std::string &command, std::vector<std::string> &parameters, LocalUser *user, bool validated, const std::string &original_line);
void OnUnloadModule(Module* mod);
bool AppliesToMe(User* user, FilterResult* filter, int flags);
void ReadFilters();
static bool StringToFilterAction(const std::string& str, FilterAction& fa);
static std::string FilterActionToString(FilterAction fa);
};
CmdResult CommandFilter::Handle(const std::vector<std::string> &parameters, User *user)
{
if (parameters.size() == 1)
{
/* Deleting a filter */
Module *me = creator;
if (static_cast<ModuleFilter *>(me)->DeleteFilter(parameters[0]))
{
user->WriteServ("NOTICE %s :*** Removed filter '%s'", user->nick.c_str(), parameters[0].c_str());
ServerInstance->SNO->WriteToSnoMask(IS_LOCAL(user) ? 'a' : 'A', "FILTER: "+user->nick+" removed filter '"+parameters[0]+"'");
return CMD_SUCCESS;
}
else
{
user->WriteServ("NOTICE %s :*** Filter '%s' not found in list, try /stats s.", user->nick.c_str(), parameters[0].c_str());
return CMD_FAILURE;
}
}
else
{
/* Adding a filter */
if (parameters.size() >= 4)
{
const std::string& freeform = parameters[0];
FilterAction type;
const std::string& flags = parameters[2];
unsigned int reasonindex;
long duration = 0;
if (!ModuleFilter::StringToFilterAction(parameters[1], type))
{
user->WriteServ("NOTICE %s :*** Invalid filter type '%s'. Supported types are 'gline', 'warn', 'block', 'silent' and 'kill'.", user->nick.c_str(), parameters[1].c_str());
return CMD_FAILURE;
}
if (type == FA_GLINE)
{
if (parameters.size() >= 5)
{
duration = ServerInstance->Duration(parameters[3]);
reasonindex = 4;
}
else
{
user->WriteServ("NOTICE %s :*** Not enough parameters: When setting a gline type filter, a gline duration must be specified as the third parameter.", user->nick.c_str());
return CMD_FAILURE;
}
}
else
{
reasonindex = 3;
}
Module *me = creator;
std::pair<bool, std::string> result = static_cast<ModuleFilter *>(me)->AddFilter(freeform, type, parameters[reasonindex], duration, flags);
if (result.first)
{
user->WriteServ("NOTICE %s :*** Added filter '%s', type '%s'%s%s, flags '%s', reason: '%s'", user->nick.c_str(), freeform.c_str(),
parameters[1].c_str(), (duration ? ", duration " : ""), (duration ? parameters[3].c_str() : ""),
flags.c_str(), parameters[reasonindex].c_str());
ServerInstance->SNO->WriteToSnoMask(IS_LOCAL(user) ? 'a' : 'A', "FILTER: "+user->nick+" added filter '"+freeform+"', type '"+parameters[1]+"', "+(duration ? "duration "+parameters[3]+", " : "")+"flags '"+flags+"', reason: "+parameters[reasonindex]);
return CMD_SUCCESS;
}
else
{
user->WriteServ("NOTICE %s :*** Filter '%s' could not be added: %s", user->nick.c_str(), freeform.c_str(), result.second.c_str());
return CMD_FAILURE;
}
}
else
{
user->WriteServ("NOTICE %s :*** Not enough parameters.", user->nick.c_str());
return CMD_FAILURE;
}
}
}
bool ModuleFilter::AppliesToMe(User* user, FilterResult* filter, int iflags)
{
if ((filter->flag_no_opers) && IS_OPER(user))
return false;
if ((iflags & FLAG_PRIVMSG) && (!filter->flag_privmsg))
return false;
if ((iflags & FLAG_NOTICE) && (!filter->flag_notice))
return false;
if ((iflags & FLAG_QUIT) && (!filter->flag_quit_message))
return false;
if ((iflags & FLAG_PART) && (!filter->flag_part_message))
return false;
return true;
}
ModuleFilter::ModuleFilter()
: initing(true), filtcommand(this), RegexEngine(this, "regex")
{
}
void ModuleFilter::init()
{
ServerInstance->Modules->AddService(filtcommand);
Implementation eventlist[] = { I_OnPreCommand, I_OnStats, I_OnSyncNetwork, I_OnDecodeMetaData, I_OnUserPreMessage, I_OnUserPreNotice, I_OnRehash, I_OnUnloadModule };
ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
OnRehash(NULL);
}
CullResult ModuleFilter::cull()
{
FreeFilters();
return Module::cull();
}
void ModuleFilter::FreeFilters()
{
for (std::vector<ImplFilter>::const_iterator i = filters.begin(); i != filters.end(); ++i)
delete i->regex;
filters.clear();
}
ModResult ModuleFilter::OnUserPreMessage(User* user,void* dest,int target_type, std::string &text, char status, CUList &exempt_list)
{
if (!IS_LOCAL(user))
return MOD_RES_PASSTHRU;
flags = FLAG_PRIVMSG;
return OnUserPreNotice(user,dest,target_type,text,status,exempt_list);
}
ModResult ModuleFilter::OnUserPreNotice(User* user,void* dest,int target_type, std::string &text, char status, CUList &exempt_list)
{
/* Leave ulines alone */
if ((ServerInstance->ULine(user->server)) || (!IS_LOCAL(user)))
return MOD_RES_PASSTHRU;
if (!flags)
flags = FLAG_NOTICE;
FilterResult* f = this->FilterMatch(user, text, flags);
if (f)
{
std::string target;
if (target_type == TYPE_USER)
{
User* t = (User*)dest;
target = t->nick;
}
else if (target_type == TYPE_CHANNEL)
{
Channel* t = (Channel*)dest;
if (exemptfromfilter.find(t->name) != exemptfromfilter.end())
return MOD_RES_PASSTHRU;
target = t->name;
}
if (f->action == FA_BLOCK)
{
ServerInstance->SNO->WriteGlobalSno('a', "FILTER: "+user->nick+" LINE BLOCKED, Target: "+target+" ("+f->reason+") Message: "+text+" Match: "+f->freeform);
if (target_type == TYPE_CHANNEL)
user->WriteNumeric(404, "%s %s :Message to channel blocked (%s)",user->nick.c_str(), target.c_str(), f->reason.c_str());
else
user->WriteServ("NOTICE "+user->nick+" :Your message to "+target+" was blocked: "+f->reason);
}
else if (f->action == FA_SILENT)
{
ServerInstance->SNO->WriteGlobalSno('a', "FILTER: "+user->nick+" LINE BLOCKED (silent), Target: "+target+" ("+f->reason+") Message: "+text+" Match: "+f->freeform);
}
else if (f->action == FA_WARN)
{
ServerInstance->SNO->WriteGlobalSno('a', "FILTER WARN: "+user->nick+", Target: "+target+" ("+f->reason+") Message: "+text+" Match: "+f->freeform);
}
else if (f->action == FA_KILL)
{
ServerInstance->Users->QuitUser(user, "Filtered: " + f->reason);
ServerInstance->SNO->WriteGlobalSno('a', "FILTER: "+user->nick+" KILLED, Target: "+target+" ("+f->reason+") Message: "+text+" Match: "+f->freeform);
}
else if (f->action == FA_GLINE)
{
GLine* gl = new GLine(ServerInstance->Time(), f->gline_time, ServerInstance->Config->ServerName.c_str(), f->reason.c_str(), "*", user->GetIPString());
if (ServerInstance->XLines->AddLine(gl,NULL))
{
ServerInstance->XLines->ApplyLines();
ServerInstance->SNO->WriteGlobalSno('a', "FILTER: "+user->nick+" GLINED (*@"+user->GetIPString()+") Target: "+target+" ("+f->reason+") Message: "+text+" Match: "+f->freeform);
}
else
delete gl;
}
ServerInstance->Logs->Log("FILTER",DEFAULT,"FILTER: "+ user->nick + " had their message filtered, target was " + target + ": " + f->reason + " Action: " + ModuleFilter::FilterActionToString(f->action));
if (f->action != FA_WARN) {
return MOD_RES_DENY;
}
}
return MOD_RES_PASSTHRU;
}
ModResult ModuleFilter::OnPreCommand(std::string &command, std::vector<std::string> &parameters, LocalUser *user, bool validated, const std::string &original_line)
{
if (validated && IS_LOCAL(user))
{
flags = 0;
bool parting;
if (command == "QUIT")
{
/* QUIT with no reason: nothing to do */
if (parameters.size() < 1)
return MOD_RES_PASSTHRU;
parting = false;
flags = FLAG_QUIT;
}
else if (command == "PART")
{
/* PART with no reason: nothing to do */
if (parameters.size() < 2)
return MOD_RES_PASSTHRU;
if (exemptfromfilter.find(parameters[0]) != exemptfromfilter.end())
return MOD_RES_PASSTHRU;
parting = true;
flags = FLAG_PART;
}
else
/* We're only messing with PART and QUIT */
return MOD_RES_PASSTHRU;
FilterResult* f = this->FilterMatch(user, parameters[parting ? 1 : 0], flags);
if (!f)
/* PART or QUIT reason doesnt match a filter */
return MOD_RES_PASSTHRU;
/* We cant block a part or quit, so instead we change the reason to 'Reason filtered' */
parameters[parting ? 1 : 0] = "Reason filtered";
/* We're blocking, OR theyre quitting and its a KILL action
* (we cant kill someone whos already quitting, so filter them anyway)
*/
if ((f->action == FA_BLOCK) || (((!parting) && (f->action == FA_KILL))) || (f->action == FA_SILENT))
{
return MOD_RES_PASSTHRU;
}
else
{
/* Are they parting, if so, kill is applicable */
if ((parting) && (f->action == FA_KILL))
{
user->WriteServ("NOTICE %s :*** Your PART message was filtered: %s", user->nick.c_str(), f->reason.c_str());
ServerInstance->Users->QuitUser(user, "Filtered: " + f->reason);
}
if (f->action == FA_GLINE)
{
/* Note: We gline *@IP so that if their host doesnt resolve the gline still applies. */
GLine* gl = new GLine(ServerInstance->Time(), f->gline_time, ServerInstance->Config->ServerName.c_str(), f->reason.c_str(), "*", user->GetIPString());
if (ServerInstance->XLines->AddLine(gl,NULL))
{
ServerInstance->XLines->ApplyLines();
}
else
delete gl;
}
return MOD_RES_DENY;
}
}
return MOD_RES_PASSTHRU;
}
void ModuleFilter::OnRehash(User* user)
{
ConfigTagList tags = ServerInstance->Config->ConfTags("exemptfromfilter");
exemptfromfilter.clear();
for (ConfigIter i = tags.first; i != tags.second; ++i)
{
std::string chan = i->second->getString("channel");
if (!chan.empty())
exemptfromfilter.insert(chan);
}
std::string newrxengine = ServerInstance->Config->ConfValue("filteropts")->getString("engine");
factory = RegexEngine ? (RegexEngine.operator->()) : NULL;
if (newrxengine.empty())
RegexEngine.SetProvider("regex");
else
RegexEngine.SetProvider("regex/" + newrxengine);
if (!RegexEngine)
{
if (newrxengine.empty())
ServerInstance->SNO->WriteGlobalSno('a', "WARNING: No regex engine loaded - Filter functionality disabled until this is corrected.");
else
ServerInstance->SNO->WriteGlobalSno('a', "WARNING: Regex engine '%s' is not loaded - Filter functionality disabled until this is corrected.", newrxengine.c_str());
initing = false;
FreeFilters();
return;
}
if ((!initing) && (RegexEngine.operator->() != factory))
{
ServerInstance->SNO->WriteGlobalSno('a', "Dumping all filters due to regex engine change");
FreeFilters();
}
initing = false;
ReadFilters();
}
Version ModuleFilter::GetVersion()
{
return Version("Text (spam) filtering", VF_VENDOR | VF_COMMON, RegexEngine ? RegexEngine->name : "");
}
std::string ModuleFilter::EncodeFilter(FilterResult* filter)
{
std::ostringstream stream;
std::string x = filter->freeform;
/* Hax to allow spaces in the freeform without changing the design of the irc protocol */
for (std::string::iterator n = x.begin(); n != x.end(); n++)
if (*n == ' ')
*n = '\7';
stream << x << " " << FilterActionToString(filter->action) << " " << filter->GetFlags() << " " << filter->gline_time << " :" << filter->reason;
return stream.str();
}
FilterResult ModuleFilter::DecodeFilter(const std::string &data)
{
std::string filteraction;
FilterResult res;
irc::tokenstream tokens(data);
tokens.GetToken(res.freeform);
tokens.GetToken(filteraction);
if (!StringToFilterAction(filteraction, res.action))
throw ModuleException("Invalid action: " + filteraction);
std::string filterflags;
tokens.GetToken(filterflags);
char c = res.FillFlags(filterflags);
if (c != 0)
throw ModuleException("Invalid flag: '" + std::string(1, c) + "'");
tokens.GetToken(res.gline_time);
tokens.GetToken(res.reason);
/* Hax to allow spaces in the freeform without changing the design of the irc protocol */
for (std::string::iterator n = res.freeform.begin(); n != res.freeform.end(); n++)
if (*n == '\7')
*n = ' ';
return res;
}
void ModuleFilter::OnSyncNetwork(Module* proto, void* opaque)
{
for (std::vector<ImplFilter>::iterator i = filters.begin(); i != filters.end(); ++i)
{
proto->ProtoSendMetaData(opaque, NULL, "filter", EncodeFilter(&(*i)));
}
}
void ModuleFilter::OnDecodeMetaData(Extensible* target, const std::string &extname, const std::string &extdata)
{
if ((target == NULL) && (extname == "filter"))
{
try
{
FilterResult data = DecodeFilter(extdata);
this->AddFilter(data.freeform, data.action, data.reason, data.gline_time, data.GetFlags());
}
catch (ModuleException& e)
{
ServerInstance->Logs->Log("m_filter", DEBUG, "Error when unserializing filter: " + std::string(e.GetReason()));
}
}
}
ImplFilter::ImplFilter(ModuleFilter* mymodule, const std::string &rea, FilterAction act, long glinetime, const std::string &pat, const std::string &flgs)
: FilterResult(pat, rea, act, glinetime, flgs)
{
if (!mymodule->RegexEngine)
throw ModuleException("Regex module implementing '"+mymodule->RegexEngine.GetProvider()+"' is not loaded!");
regex = mymodule->RegexEngine->Create(pat);
}
FilterResult* ModuleFilter::FilterMatch(User* user, const std::string &text, int flgs)
{
static std::string stripped_text;
stripped_text.clear();
for (std::vector<ImplFilter>::iterator index = filters.begin(); index != filters.end(); index++)
{
FilterResult* filter = dynamic_cast<FilterResult*>(&(*index));
/* Skip ones that dont apply to us */
if (!AppliesToMe(user, filter, flgs))
continue;
if ((filter->flag_strip_color) && (stripped_text.empty()))
{
stripped_text = text;
InspIRCd::StripColor(stripped_text);
}
//ServerInstance->Logs->Log("m_filter", DEBUG, "Match '%s' against '%s'", text.c_str(), index->freeform.c_str());
if (index->regex->Matches(filter->flag_strip_color ? stripped_text : text))
{
//ServerInstance->Logs->Log("m_filter", DEBUG, "MATCH");
return &*index;
}
//ServerInstance->Logs->Log("m_filter", DEBUG, "NO MATCH");
}
return NULL;
}
bool ModuleFilter::DeleteFilter(const std::string &freeform)
{
for (std::vector<ImplFilter>::iterator i = filters.begin(); i != filters.end(); i++)
{
if (i->freeform == freeform)
{
delete i->regex;
filters.erase(i);
return true;
}
}
return false;
}
std::pair<bool, std::string> ModuleFilter::AddFilter(const std::string &freeform, FilterAction type, const std::string &reason, long duration, const std::string &flgs)
{
for (std::vector<ImplFilter>::iterator i = filters.begin(); i != filters.end(); i++)
{
if (i->freeform == freeform)
{
return std::make_pair(false, "Filter already exists");
}
}
try
{
filters.push_back(ImplFilter(this, reason, type, duration, freeform, flgs));
}
catch (ModuleException &e)
{
ServerInstance->Logs->Log("m_filter", DEFAULT, "Error in regular expression '%s': %s", freeform.c_str(), e.GetReason());
return std::make_pair(false, e.GetReason());
}
return std::make_pair(true, "");
}
bool ModuleFilter::StringToFilterAction(const std::string& str, FilterAction& fa)
{
irc::string s(str.c_str());
if (s == "gline")
fa = FA_GLINE;
else if (s == "block")
fa = FA_BLOCK;
else if (s == "silent")
fa = FA_SILENT;
else if (s == "kill")
fa = FA_KILL;
else if (s == "warn")
fa = FA_WARN;
else
return false;
return true;
}
std::string ModuleFilter::FilterActionToString(FilterAction fa)
{
switch (fa)
{
case FA_GLINE: return "gline";
case FA_BLOCK: return "block";
case FA_SILENT: return "silent";
case FA_KILL: return "kill";
default: return "warn";
}
}
void ModuleFilter::ReadFilters()
{
ConfigTagList tags = ServerInstance->Config->ConfTags("keyword");
for (ConfigIter i = tags.first; i != tags.second; ++i)
{
std::string pattern = i->second->getString("pattern");
this->DeleteFilter(pattern);
std::string reason = i->second->getString("reason");
std::string action = i->second->getString("action");
std::string flgs = i->second->getString("flags");
long gline_time = ServerInstance->Duration(i->second->getString("duration"));
if (flgs.empty())
flgs = "*";
FilterAction fa;
if (!StringToFilterAction(action, fa))
fa = FA_WARN;
try
{
filters.push_back(ImplFilter(this, reason, fa, gline_time, pattern, flgs));
ServerInstance->Logs->Log("m_filter", DEFAULT, "Regular expression %s loaded.", pattern.c_str());
}
catch (ModuleException &e)
{
ServerInstance->Logs->Log("m_filter", DEFAULT, "Error in regular expression '%s': %s", pattern.c_str(), e.GetReason());
}
}
}
ModResult ModuleFilter::OnStats(char symbol, User* user, string_list &results)
{
if (symbol == 's')
{
for (std::vector<ImplFilter>::iterator i = filters.begin(); i != filters.end(); i++)
{
results.push_back(ServerInstance->Config->ServerName+" 223 "+user->nick+" :"+RegexEngine.GetProvider()+":"+i->freeform+" "+i->GetFlags()+" "+FilterActionToString(i->action)+" "+ConvToStr(i->gline_time)+" :"+i->reason);
}
for (std::set<std::string>::iterator i = exemptfromfilter.begin(); i != exemptfromfilter.end(); ++i)
{
results.push_back(ServerInstance->Config->ServerName+" 223 "+user->nick+" :EXEMPT "+(*i));
}
}
return MOD_RES_PASSTHRU;
}
void ModuleFilter::OnUnloadModule(Module* mod)
{
// If the regex engine became unavailable or has changed, remove all filters
if (!RegexEngine)
{
FreeFilters();
}
else if (RegexEngine.operator->() != factory)
{
factory = RegexEngine.operator->();
FreeFilters();
}
}
MODULE_INIT(ModuleFilter)
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